[Federal Register Volume 85, Number 60 (Friday, March 27, 2020)]
[Proposed Rules]
[Pages 17382-17431]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2020-05914]



[[Page 17381]]

Vol. 85

Friday,

No. 60

March 27, 2020

Part II





Environmental Protection Agency





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40 CFR Part 52





Clean Air Plans; 2006 Fine Particulate Matter Nonattainment Area 
Requirements; San Joaquin Valley, California; Proposed Rule

  Federal Register / Vol. 85 , No. 60 / Friday, March 27, 2020 / 
Proposed Rules  

[[Page 17382]]


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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 52

[EPA-R09-OAR-2019-0318; FRL-10006-40-Region 9]


Clean Air Plans; 2006 Fine Particulate Matter Nonattainment Area 
Requirements; San Joaquin Valley, California

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.

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SUMMARY: The Environmental Protection Agency (EPA or ``Agency'') 
proposes to approve portions of two state implementation plan (SIP) 
revisions submitted by the State of California to meet Clean Air Act 
(CAA or ``Act'') requirements for the 2006 fine particulate matter 
(PM2.5) national ambient air quality standards (NAAQS or 
``standards'') in the San Joaquin Valley (SJV) Serious nonattainment 
area. Specifically, the EPA proposes to approve those portions of the 
``2018 Plan for the 1997, 2006, and 2012 PM2.5 Standards'' 
and the ``San Joaquin Valley Supplement to the 2016 State Strategy for 
the State Implementation Plan'' that pertain to the 2006 
PM2.5 NAAQS and address CAA requirements for Serious 
PM2.5 nonattainment areas. The EPA also proposes to approve 
inter-pollutant trading ratios for use in transportation conformity 
analyses for the 2006 PM2.5 NAAQS. As part of this action, 
the EPA proposes to grant an extension of the Serious area attainment 
date for the 2006 PM2.5 NAAQS in the San Joaquin Valley from 
December 31, 2019, to December 31, 2024 based on a proposed 
determination that the State has satisfied the statutory criteria for 
this extension. We may, however, reconsider this proposal or deny 
California's request for extension of the attainment date if, based on 
new information or public comments, we find that the State has not 
satisfied the statutory criteria for this extension.

DATES: Any comments must arrive by April 27, 2020.

ADDRESSES: Submit your comments, identified by Docket ID No. EPA-R09-
OAR-2019-0318, at https://www.regulations.gov. For comments submitted 
at Regulations.gov, follow the online instructions for submitting 
comments. Once submitted, comments cannot be edited or removed from 
Regulations.gov. The EPA may publish any comment received to its public 
docket. Do not submit electronically any information you consider to be 
Confidential Business Information (CBI) or other information whose 
disclosure is restricted by statute. Multimedia submissions (audio, 
video, etc.) must be accompanied by a written comment. The written 
comment is considered the official comment and should include 
discussion of all points you wish to make. The EPA will generally not 
consider comments or comment contents located outside of the primary 
submission (i.e., on the web, cloud, or other file sharing system). For 
additional submission methods, please contact the person identified in 
the FOR FURTHER INFORMATION CONTACT section. For the full EPA public 
comment policy, information about CBI or multimedia submissions, and 
general guidance on making effective comments, please visit https://www.epa.gov/dockets/commenting-epa-dockets.

FOR FURTHER INFORMATION CONTACT: Rory Mays, Air Planning Office (AIR-
2), EPA Region IX, (415) 972-3227, [email protected].

SUPPLEMENTARY INFORMATION:  Throughout this document, ``we,'' ``us,'' 
and ``our'' refer to the EPA.

Table of Contents

I. Background
II. Summary and Completeness Review of the San Joaquin Valley 
PM2.5 Plan
    A. 2018 PM2.5 Plan
    B. Valley State SIP Strategy
III. Clean Air Act Requirements for PM2.5 Serious Area 
Plans
    A. Requirements for PM2.5 Serious Area Plans
    B. Requirements for Extension of a Serious Area Attainment Date
IV. Review of the San Joaquin Valley PM2.5 Serious Area 
Plan and Extension Application
    A. Emissions Inventory
    B. PM2.5 Precursors
    C. Best Available Control Measures and Most Stringent Measures
    D. Extension of Serious Area Attainment Date Under CAA Section 
188(e)
    E. Reasonable Further Progress and Quantitative Milestones
    F. Motor Vehicle Emission Budgets
    G. Major Stationary Source Control Requirements Under CAA 
Section 189(e)
V. Summary of Proposed Actions and Request for Public Comment
VI. Statutory and Executive Order Reviews

I. Background

    On October 17, 2006, the EPA strengthened the 24-hour (daily) NAAQS 
for particles less than or equal to 2.5 micrometers ([micro]m) in 
diameter (PM2.5) by lowering the level from 65 micrograms 
([micro]g) per cubic meter (m\3\) to 35 [micro]g/m\3\.\1\ The 24-hour 
standards are based on a three-year average of 98th percentile 24-hour 
PM2.5 concentrations. The EPA established these standards 
after considering substantial evidence from numerous health studies 
demonstrating that serious health effects are associated with exposures 
to PM2.5 concentrations above these levels.
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    \1\ 71 Federal Register (FR) 61144 (October 17, 2006) and 40 CFR 
50.13. In promulgating the 2006 PM2.5 NAAQS, the EPA 
retained the level of the 1997 annual average PM2.5 NAAQS 
of 15.0 [micro]g/m\3\. 62 FR 36852 (July 18, 1997) and 40 CFR 50.7. 
Subsequently, the EPA strengthened the primary annual 
PM2.5 NAAQS by lowering the level to 12.0 [micro]g/m\3\ 
while retaining the secondary annual PM2.5 NAAQS at the 
level of 15.0 [micro]g/m\3\. 78 FR 3086 (January 15, 2013) and 40 
CFR 50.18. In this preamble, all references to the PM2.5 
NAAQS, unless otherwise specified, are to the 2006 24-hour standards 
(35 [micro]g/m\3\) as codified in 40 CFR 50.13.
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    Epidemiological studies have shown statistically significant 
correlations between elevated PM2.5 levels and premature 
mortality. Other important health effects associated with 
PM2.5 exposure include aggravation of respiratory and 
cardiovascular disease (as indicated by increased hospital admissions, 
emergency room visits, absences from school or work, and restricted 
activity days), changes in lung function and increased respiratory 
symptoms, and new evidence for more subtle indicators of cardiovascular 
health. Individuals particularly sensitive to PM2.5 exposure 
include older adults, people with heart and lung disease, and 
children.\2\
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    \2\ EPA, Air Quality Criteria for Particulate Matter, No. EPA/
600/P-99/002aF and EPA/600/P-99/002bF, October 2004.
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    PM2.5 can be emitted directly into the atmosphere as a 
solid or liquid particle (primary PM2.5 or direct 
PM2.5) or can be formed in the atmosphere as a result of 
various chemical reactions from precursor emissions of nitrogen oxides, 
sulfur oxides, volatile organic compounds, and ammonia (secondary 
PM2.5).\3\
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    \3\ 81 FR 58010, 58011 (August 24, 2016).
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    Following promulgation of a new or revised NAAQS, the EPA is 
required under CAA section 107(d) to designate areas throughout the 
nation as attaining or not attaining the NAAQS. Effective December 14, 
2009, the EPA finalized initial air quality designations for the 2006 
PM2.5 NAAQS, using air quality monitoring data for the 
three-year periods of 2005-2007 and 2006-2008.\4\ The EPA designated 
the San Joaquin Valley as a nonattainment area for the 2006 
PM2.5 NAAQS.\5\ On June 2, 2014, the EPA classified the San 
Joaquin Valley as a Moderate nonattainment area for these NAAQS, 
thereby establishing December 31, 2015 as the

[[Page 17383]]

latest permissible attainment date for the area under section 188(c)(1) 
of the CAA.\6\ Effective February 19, 2016, the EPA reclassified the 
San Joaquin Valley as a Serious nonattainment area for these NAAQS.\7\ 
Shortly thereafter, the EPA approved the State's demonstration that it 
was impracticable to attain the 2006 PM2.5 NAAQS by the 
December 31, 2015 Moderate area attainment date and related plan 
elements addressing the Moderate area requirements for the 2006 
PM2.5 NAAQS.\8\
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    \4\ 74 FR 58688 (November 13, 2009).
    \5\ Id. (codified at 40 CFR 81.305). The most recent 24-hour 
design value (2016-2018) for the San Joaquin Valley is 65 [micro]g/
m\3\. EPA design value workbook dated July 18, 2019, worksheet 
``Table 1b.''
    \6\ 79 FR 31566 (June 2, 2014). The EPA promulgated these 
PM2.5 nonattainment area classifications in response to a 
2013 decision of the Court of Appeals for the D.C. Circuit remanding 
the EPA's prior implementation rule for the PM2.5 NAAQS 
and directing the EPA to repromulgate implementation rules pursuant 
to subpart 4 of part D, title I of the Act. Natural Resources 
Defense Council v. EPA, 706 F.3d 428 (D.C. Cir. 2013).
    \7\ 81 FR 2993 (January 20, 2016).
    \8\ 81 FR 59876 (August 31, 2016).
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    Upon reclassification as a Serious PM2.5 nonattainment 
area, the San Joaquin Valley became subject to a new statutory 
attainment date no later than the end of the tenth calendar year 
following designation (i.e., December 31, 2019) and the requirement to 
submit a Serious area plan satisfying the requirements of CAA Title I, 
part D, including the requirements of subpart 4, for the 2006 
PM2.5 NAAQS.\9\ As explained in the EPA's final 
reclassification action, the Serious area plan for the San Joaquin 
Valley must include, among other things, provisions to assure that, 
under CAA section 189(b)(1)(B), the best available control measures 
(BACM) for the control of direct PM2.5 and PM2.5 
precursors shall be implemented no later than four years after the area 
is reclassified and a demonstration (including air quality modeling) 
that the plan provides for attainment as expeditiously as practicable 
and no later than the applicable attainment date. The EPA established 
an August 21, 2017 deadline for California to adopt and submit a SIP 
submission addressing the Serious nonattainment area requirements for 
the 2006 PM2.5 NAAQS.\10\ The EPA also noted that California 
may choose to submit a request for an extension of the December 31, 
2019, Serious area attainment date pursuant to CAA section 188(e) 
simultaneously with its submission of a Serious area plan for the 
area.\11\
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    \9\ 81 FR 2993, 2998.
    \10\ Id. at 3000 and 81 FR 42263 (June 29, 2016) (codified at 40 
CFR 52.247(f)).
    \11\ 81 FR 2993, 2998.
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    As described further in section III.B of this preamble, CAA section 
188(e) allows the EPA to extend the attainment date for a Serious area 
by up to five years if attainment by the Serious area attainment date 
is impracticable. However, before the Agency may grant an extension of 
the attainment date, the State must first:
    (1) Apply to the EPA for an extension of the PM2.5 
attainment date beyond 2019,
    (2) demonstrate that attainment by 2019 is impracticable,
    (3) have complied with all requirements and commitments applying to 
the area in its implementation plan,
    (4) demonstrate to the Administrator's satisfaction that its 
Serious area plan includes the most stringent measures that are 
achieved in practice in any state and are feasible for the area, and
    (5) submit SIP revisions containing a demonstration of attainment 
by the most expeditious alternative date practicable.
    The San Joaquin Valley PM2.5 nonattainment area 
encompasses over 23,000 square miles and includes all or part of eight 
counties: San Joaquin, Stanislaus, Merced, Madera, Fresno, Tulare, 
Kings, and the valley portion of Kern.\12\ The area is home to four 
million people and is the nation's leading agricultural region. 
Stretching over 250 miles from north to south and averaging 80 miles 
wide, it is partially enclosed by the Coast Mountain range to the west, 
the Tehachapi Mountains to the south, and the Sierra Nevada range to 
the east. The San Joaquin Valley Unified Air Pollution Control District 
(SJVUAPCD or District) has primary responsibility for developing plans 
to provide for attainment of the NAAQS in this area. The District works 
cooperatively with the California Air Resources Board (CARB) in 
preparing attainment plans. Authority for regulating sources under 
state jurisdiction in the San Joaquin Valley is split between the 
District, which has responsibility for regulating stationary and most 
area sources, and CARB, which has responsibility for regulating most 
mobile sources.
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    \12\ For a precise description of the geographic boundaries of 
the San Joaquin Valley PM2.5 nonattainment area, see 40 
CFR 81.305.
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    On November 16, 2018, CARB submitted to the EPA substantial 
portions of the Serious area plan for the 2006 PM2.5 NAAQS 
following CARB's adoption of one component of the plan on October 25, 
2018 and the SJVUAPCD's adoption of a second component of it on 
November 15, 2018.\13\ Because CARB had not yet adopted this submission 
in its entirety, the EPA determined that it did not meet the EPA's 
completeness requirements for SIP submissions under 40 CFR part 51, 
Appendix V, section 2.1.\14\ The EPA's incompleteness findings became 
effective on January 7, 2019, and triggered clocks for the application 
of emissions offset sanctions for new or modified major stationary 
sources in the San Joaquin Valley 18 months after the effective date of 
the findings and highway funding sanctions six months thereafter, 
unless the EPA affirmatively determines that the State has submitted a 
complete SIP addressing the deficiency that was the basis for these 
findings, consistent with CAA section 179(b) and the EPA's sanctions 
sequencing rule in 40 CFR 52.31.\15\ These findings also triggered the 
obligation under CAA section 110(c) on the EPA to promulgate a federal 
implementation plan no later than two years after the effective date of 
the findings, unless the State has submitted, and the EPA has approved, 
the required SIP submittal.\16\
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    \13\ Letter dated November 16, 2018, from Kurt Karperos, Deputy 
Executive Officer, CARB, to Mike Stoker, Regional Administrator, EPA 
Region IX.
    \14\ 83 FR 62720 (December 6, 2018). The EPA made these findings 
in response to a court order issued in Committee for a Better Arvin, 
et al., v. Andrew Wheeler, et al., Case No. 18-cv-05700-RS (N.D. 
Cal., October 24, 2018).
    \15\ 83 FR 62720, 62723.
    \16\ Id.
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II. Summary and Completeness Review of the San Joaquin Valley PM2.5 
Plan

    The EPA is proposing action on portions of two SIP revisions 
submitted by CARB to meet the Serious nonattainment area requirements 
for the 2006 24-hour PM2.5 NAAQS in the San Joaquin Valley. 
Specifically, the EPA is proposing to act on those portions of the 
following two plan submissions that pertain to the 2006 24-hour 
PM2.5 NAAQS: The ``2018 Plan for the 1997, 2006, and 2012 
PM2.5 Standards,'' adopted by the SJVUAPCD on November 15, 
2018, and by CARB on January 24, 2019 (``2018 PM2.5 Plan'') 
\17\; and the ``San Joaquin Valley Supplement to the 2016 State 
Strategy for the State Implementation Plan,'' adopted by CARB on 
October 25, 2018 (``Valley State SIP Strategy''). We refer to the 
relevant portions of these SIP submissions collectively as the ``SJV 
PM2.5 Plan'' or ``Plan.'' The SJV PM2.5 Plan 
addresses the Serious area attainment plan requirements for the 2006 
24-hour PM2.5 NAAQS in the San Joaquin Valley and includes a 
request under CAA section 188(e) for an extension of the Serious area 
attainment date for the area for this NAAQS. CARB submitted the SJV 
PM2.5 Plan to the EPA

[[Page 17384]]

as a revision to the SIP on May 10, 2019.\18\
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    \17\ The 2018 PM2.5 Plan was developed jointly by 
CARB and the District.
    \18\ Letter dated May 9, 2019, from Richard Corey, Executive 
Officer, CARB, to Mike Stoker, Regional Administrator, EPA Region 9. 
The EPA is not, at this time, proposing to act on those portions of 
the ``2018 Plan for the 1997, 2006, and 2012 PM2.5 
Standards'' or the ``San Joaquin Valley Supplement to the 2016 State 
Strategy for the State Implementation Plan'' that pertain to the 
1997 PM2.5 NAAQS, the 2012 PM2.5 NAAQS, or 
Serious area contingency measures. We intend to act on these 
portions of the submitted SIP revisions in subsequent rulemakings.
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    CAA sections 110(a)(1) and (2) and 110(l) require each state to 
provide reasonable public notice and opportunity for public hearing 
prior to the adoption and submission of a SIP or SIP revision to the 
EPA. To meet this requirement, every SIP submission should include 
evidence that adequate public notice was given and that an opportunity 
for a public hearing was provided consistent with the EPA's 
implementing regulations in 40 CFR 51.102.
    CAA section 110(k)(1)(B) requires the EPA to determine whether a 
SIP submission is complete within 60 days of receipt. This section also 
provides that any plan that the EPA has not affirmatively determined to 
be complete or incomplete will become complete by operation of law six 
months after the date of submission. The EPA's SIP completeness 
criteria are found in 40 CFR part 51, Appendix V.

A. 2018 PM2.5 Plan

    The following portions of the 2018 PM2.5 Plan and 
related support documents address the Serious area requirements for the 
2006 PM2.5 NAAQS in the San Joaquin Valley: (i) Chapter 4 
(``Attainment Strategy for PM2.5''); (ii) Chapter 6 
(``Demonstration of Federal Requirements for the 2006 PM2.5 
Standard: Serious Plan and Extension Request''); \19\ (iii) numerous 
appendices to the 2018 PM2.5 Plan; (iv) CARB's ``Staff 
Report, Review of the San Joaquin Valley 2018 Plan for the 1997, 2006, 
and 2012 PM2.5 Standards,'' release date December 21, 2018 
(``CARB Staff Report''); \20\ and (v) the State's and District's board 
resolutions adopting the 2018 PM2.5 Plan (CARB Resolution 
19-1 and SJVUAPCD Governing Board Resolution 18-11-16).\21\ The 
SJVUAPCD Governing Board Resolution 18-11-16 includes emission 
reduction commitments on which the SJV PM2.5 Plan 
relies.\22\
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    \19\ Chapter 5 (``Demonstration of Federal Requirements for the 
1997 PM2.5 Standard'') and Chapter 7 (``Demonstration of 
Federal Requirements for the 2012 PM2.5 Standard'') of 
the 2018 PM2.5 Plan pertain to the 1997 PM2.5 
NAAQS and 2012 PM2.5 NAAQS, respectively. The EPA intends 
to act on these portions of the 2018 PM2.5 Plan in 
separate rulemakings.
    \20\ The CARB Staff Report includes CARB's review of, among 
other things, the 2018 PM2.5 Plan's control strategy and 
attainment demonstration. Letter dated December 11, 2019 from 
Richard Corey, Executive Officer, CARB to Mike Stoker, Regional 
Administrator, EPA Region IX, transmitting the CARB Staff Report [on 
the 2018 PM2.5 Plan].
    \21\ CARB Resolution 19-1, ``2018 PM2.5 State 
Implementation Plan for the San Joaquin Valley,'' January 24, 2019, 
and SJVUAPCD Governing Board Resolution 18-11-16, ``Adopting the 
[SJVUAPCD] 2018 Plan for the 1997, 2006, and 2012 PM2.5 
Standards,'' November 15, 2018.
    \22\ SJVUAPCD Governing Board Resolution 18-11-16, paragraph 6, 
10-11.
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    The appendices to the 2018 PM2.5 Plan, in order of their 
evaluation in this preamble, include: (i) App. B (``Emissions 
Inventory''); (ii) App. A (``Ambient PM2.5 Data Analysis''); 
(iii) a plan precursor demonstration and clarifications, including App. 
G (``Precursor Demonstration'') and Attachment A (``Clarifying 
information for the San Joaquin Valley 2018 Plan regarding model 
sensitivity related to ammonia and ammonia controls'') to the CARB 
Staff Report; (iv) control strategy appendices, including App. C 
(``Stationary Source Control Measure Analyses''), App. D (``Mobile 
Source Control Measures Analyses''), and App. E (``Incentive-Based 
Strategy''); (v) modeling appendices, including App. J (``Modeling 
Emission Inventory''), App. K (``Modeling Attainment Demonstration''), 
and App. L (``Modeling Protocol''); (vi) App. H (``RFP, Quantitative 
Milestones, and Contingency''); and (vii) App. I (``New Source Review 
and Emission Reduction Credits''). The 2018 PM2.5 Plan 
addresses motor vehicle emission budget (MVEB) requirements in the 
``Transportation Conformity'' section of App. D (pages D-119 to D-131). 
The 2018 PM2.5 Plan also includes an Executive Summary, 
Introduction (Ch. 1), chapters on ``Air Quality Challenges and Trends'' 
(Ch. 2) and ``Health Impacts and Health Risk Reduction Strategy'' (Ch. 
3), and an appendix on ``Public Education and Technology Advancement'' 
(App. F).
    The District provided public notice and opportunity for public 
comment prior to its November 15, 2018 public hearing on and adoption 
of the 2018 PM2.5 Plan.\23\ CARB also provided public notice 
and opportunity for public comment prior to its January 24, 2019 public 
hearing on and adoption of the 2018 PM2.5 Plan.\24\ The SIP 
submission includes proof of publication of notices for the respective 
public hearings. It also includes copies of the written and oral 
comments received during the State's and District's public review 
processes and the agencies' responses thereto.\25\ Therefore, we find 
that the 2018 PM2.5 Plan meets the procedural requirements 
for public notice and hearing in CAA sections 110(a) and 110(l) and 40 
CFR 51.102. The 2018 PM2.5 Plan became complete by operation 
of law on November 10, 2019. The sanctions clocks that were triggered 
by our December 6, 2018 findings that the State had failed to submit 
complete SIP submissions addressing the statutory requirements that 
apply to areas designated nonattainment for the PM2.5 NAAQS, 
however, will continue to run until the EPA affirmatively determines, 
by letter to the Governor of California, that CARB has submitted a 
complete SIP submission addressing the identified deficiencies.\26\
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    \23\ SJVUAPCD, ``Notice of Public Hearing for Adoption of 
Proposed 2018 PM2.5 Plan for the 1997, 2006, and 2012 
Standards,'' October 16, 2018, and SJVUAPCD Governing Board 
Resolution 18-11-16.
    \24\ CARB, ``Notice of Public Meeting to Consider the 2018 
PM2.5 State Implementation Plan for the San Joaquin 
Valley,'' December 21, 2018, and CARB Resolution 19-1.
    \25\ CARB, ``Board Meeting Comments Log,'' March 29, 2019; J&K 
Court Reporting, LLC, ``Meeting, State of California Air Resources 
Board,'' January 24, 2019 (transcript of CARB's public hearing), and 
2018 PM2.5 Plan, App. M (``Summary of Significant 
Comments and Responses'').
    \26\ 83 FR 62720 (citing required process for termination of 
sanctions clocks in 40 CFR 52.31(d)(5)).
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B. Valley State SIP Strategy

    CARB developed the ``Revised Proposed 2016 State Strategy for the 
State Implementation Plan'' (``2016 State Strategy'') to support 
attainment planning in the San Joaquin Valley and Los Angeles-South 
Coast Air Basin (``South Coast'') ozone nonattainment areas.\27\ In its 
resolution adopting the 2016 State Strategy (CARB Resolution 17-7), the 
Board found that the 2016 State Strategy would achieve 6 tons per day 
(tpd) of NOX emission reductions and 0.1 tpd of direct 
PM2.5 emission reductions in the San Joaquin Valley by 2025 
and directed CARB staff to work with the SJVUAPCD to identify 
additional reductions from sources under District regulatory authority 
as part of a comprehensive plan to attain the PM2.5 
standards for the San Joaquin Valley and to return to the Board with a 
commitment to achieve additional emission reductions from mobile 
sources.\28\
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    \27\ The EPA has approved certain commitments made by CARB in 
the 2016 State Strategy for purposes of attaining the ozone NAAQS in 
the San Joaquin Valley and South Coast ozone nonattainment areas. 
See, e.g., 84 FR 3302 (February 12, 2019) and 84 FR 52005 (October 
1, 2019).
    \28\ CARB Resolution 17-7, ``2016 State Strategy for the State 
Implementation Plan,'' March 23, 2017, 6-7.

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[[Page 17385]]

    CARB responded to this resolution by developing and adopting the 
``San Joaquin Valley Supplement to the 2016 State Strategy for the 
State Implementation Plan'' (``Valley State SIP Strategy'') to support 
the 2018 PM2.5 Plan. The State's May 10, 2019 SIP submission 
incorporates by reference the Valley State SIP Strategy as adopted by 
CARB on October 25, 2018 and submitted to the EPA on November 16, 
2018.\29\
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    \29\ Letter dated May 9, 2019, from Richard Corey, Executive 
Officer, CARB, to Mike Stoker, Regional Administrator, EPA Region 9, 
2.
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    The Valley State SIP Strategy includes an Introduction (Ch. 1), a 
chapter on ``Measures'' (Ch. 2), and a ``Supplemental State Commitment 
from the Proposed State Measures for the Valley'' (Ch. 3). Much of the 
content of the Valley State SIP Strategy is reproduced in Chapter 4 
(``Attainment Strategy for PM2.5'') of the 2018 
PM2.5 Plan.\30\ The Valley State SIP Strategy also includes 
CARB Resolution 18-49, which, among other things, commits CARB to 
achieve specific amounts of NOX and PM2.5 
emission reductions by specific years, for purposes of attaining the 
PM2.5 NAAQS in the San Joaquin Valley.\31\
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    \30\ For example, Table 2 (proposed mobile source measures and 
schedule), Table 3 (emissions reductions from proposed mobile source 
measures), and Table 4 (summary of emission reduction measures) of 
the Valley State SIP Strategy correspond to Tables 4-8, 4-9, and 4-
7, respectively, of the 2018 PM2.5 Plan, Chapter 4.
    \31\ CARB Resolution 18-49, ``San Joaquin Valley Supplement to 
the 2016 State Strategy for the State Implementation Plan,'' October 
25, 2018, 5.
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    CARB provided the required public notice and opportunity for public 
comment prior to its October 25, 2018 public hearing on and adoption of 
the Valley State SIP Strategy.\32\ The SIP submission includes proof of 
publication of the public notice for this public hearing. It also 
includes copies of the written and oral comments received during the 
State's public review process and CARB's responses thereto.\33\ 
Therefore, we find that the Valley State SIP Strategy meets the 
procedural requirements for public notice and hearing in CAA sections 
110(a) and 110(l) and 40 CFR 51.102.
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    \32\ CARB, ``Notice of Public Meeting to Consider the San 
Joaquin Valley Supplement to the 2016 State Strategy for the State 
Implementation Plan,'' September 21, 2018, and CARB Resolution 18-
49.
    \33\ CARB, ``Board Meeting Comments Log,'' November 2, 2018 and 
compilation of written comments; and J&K Court Reporting, LLC, 
``Meeting, State of California Air Resources Board,'' October 25, 
2018 (transcript of CARB's public hearing).
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    The Valley State SIP Strategy became complete by operation of law 
on November 10, 2019. The sanctions clocks that were triggered by our 
December 6, 2018 findings that the State had failed to submit complete 
SIP submissions addressing the statutory requirements that apply to 
areas designated nonattainment for the PM2.5 NAAQS, however, 
will continue to run until the EPA affirmatively determines, by letter 
to the Governor of California, that CARB has submitted a complete SIP 
submission addressing the identified deficiencies.\34\
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    \34\ 83 FR 62720 (citing required process for termination of 
sanctions clocks in 40 CFR 52.31(d)(5)).
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III. Clean Air Act Requirements for PM2.5 Serious Area Plans

A. Requirements for PM2.5 Serious Area Plans

    Upon reclassification of a Moderate nonattainment area as a Serious 
nonattainment area under subpart 4 of part D, title I of the CAA, the 
Act requires the state to make a SIP submission that addresses the 
following Serious nonattainment area requirements: \35\
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    \35\ 81 FR 58010, 58074-58075.
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    (1) A comprehensive, accurate, current inventory of actual 
emissions from all sources of PM2.5 and PM2.5 
precursors in the area (CAA section 172(c)(3));
    (2) Provisions to assure that the best available control measures 
(BACM), including best available control technology (BACT), for the 
control of direct PM2.5 and PM2.5 precursors 
shall be implemented no later than four years after the area is 
reclassified (CAA section 189(b)(1)(B));
    (3) A demonstration (including air quality modeling) that the plan 
provides for attainment as expeditiously as practicable but no later 
than the end of the tenth calendar year after designation as a 
nonattainment area (i.e., December 31, 2019, for the San Joaquin Valley 
for the 2006 PM2.5 NAAQS), or where the state is seeking an 
extension of the attainment date under section 188(e), a demonstration 
that attainment by such date is impracticable and that the plan 
provides for attainment by the most expeditious alternative date 
practicable that is no more than five years later (CAA sections 
188(c)(2) and 189(b)(1)(A));
    (4) Plan provisions that require reasonable further progress (RFP) 
(CAA section 172(c)(2));
    (5) Quantitative milestones which are to be achieved every three 
years until the area is redesignated attainment and which demonstrate 
RFP toward attainment by the applicable date (CAA section 189(c));
    (6) Provisions to assure that control requirements applicable to 
major stationary sources of PM2.5 also apply to major 
stationary sources of PM2.5 precursors, except where the 
state demonstrates to the EPA's satisfaction that such sources do not 
contribute significantly to PM2.5 levels that exceed the 
standard in the area (CAA section 189(e));
    (7) Contingency measures to be implemented if the area fails to 
meet RFP or to attain by the applicable attainment date (CAA section 
172(c)(9)); and
    (8) A revision to the nonattainment new source review (NSR) program 
to lower the applicable ``major stationary source'' \36\ thresholds 
from 100 tons per year (tpy) to 70 tpy (CAA section 189(b)(3)).
---------------------------------------------------------------------------

    \36\ For any Serious area, the terms ``major source'' and 
``major stationary source'' include any stationary source that emits 
or has the potential to emit at least 70 tons per year of 
PM2.5. CAA section 189(b)(3) and 40 CFR 
51.165(a)(1)(iv)(A)(1)(vii) and (viii) (defining ``major stationary 
source'' in serious PM2.5 nonattainment areas).
---------------------------------------------------------------------------

    Serious area plans must also satisfy the requirements for Moderate 
area plans in CAA section 189(a), to the extent the state has not 
already met those requirements in the Moderate area plan submitted for 
the area. In addition, the Serious area plan must meet the general 
requirements applicable to all SIP submissions under section 110 of the 
CAA, including the requirement to provide necessary assurances that the 
implementing agencies have adequate personnel, funding, and authority 
under section 110(a)(2)(E); and the requirements concerning enforcement 
provisions in section 110(a)(2)(C).
    The EPA provided its preliminary views on the CAA's requirements 
for particulate matter plans under part D, title I of the Act in the 
following guidance documents: (1) ``State Implementation Plans; General 
Preamble for the Implementation of Title I of the Clean Air Act 
Amendments of 1990'' (``General Preamble''); \37\ (2) ``State 
Implementation Plans; General Preamble for the Implementation of Title 
I of the Clean Air Act Amendments of 1990; Supplemental'' (``General 
Preamble Supplement''); \38\ and (3) ``State Implementation Plans for 
Serious PM-10 Nonattainment Areas, and Attainment Date Waivers for PM-
10 Nonattainment Areas Generally; Addendum to the General Preamble for 
the Implementation of Title I of the Clean Air Act Amendments of 1990'' 
(``General Preamble Addendum'').\39\

[[Page 17386]]

More recently, in an August 24, 2016 final rule entitled, ``Fine 
Particulate Matter National Ambient Air Quality Standards: State 
Implementation Plan Requirements'' (``PM2.5 SIP Requirements 
Rule''), the EPA established regulatory requirements and provided 
further interpretive guidance on the statutory SIP requirements that 
apply to areas designated nonattainment for the PM2.5 
standards.\40\ We discuss these regulatory requirements and 
interpretations of the Act as appropriate in our evaluation of the SJV 
PM2.5 Plan below.
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    \37\ 57 FR 13498 (April 16, 1992).
    \38\ 57 FR 18070 (April 28, 1992).
    \39\ 59 FR 41998 (August 16, 1994).
    \40\ 81 FR 58010 (August 24, 2016).
---------------------------------------------------------------------------

B. Requirements for Extension of a Serious Area Attainment Date

    Under section 188(e) of the Act, a state may apply to the EPA for a 
single extension of the Serious area attainment date by up to five 
years, which the EPA may grant if the state satisfies certain 
conditions. Before the EPA may extend the attainment date for a Serious 
area under section 188(e), the state must:
    (1) Apply for an extension of the attainment date beyond the 
statutory attainment date;
    (2) demonstrate that attainment by the statutory attainment date is 
impracticable;
    (3) demonstrate that it has complied with all requirements and 
commitments pertaining to the area in the implementation plan;
    (4) demonstrate to the satisfaction of the Administrator that the 
plan for the area includes the ``most stringent measures'' that are 
included in the implementation plan of any state or are achieved in 
practice in any state, and can feasibly be implemented in the area; and
    (5) submit a demonstration of attainment by the most expeditious 
alternative date practicable.\41\
---------------------------------------------------------------------------

    \41\ CAA section 188(e) and 40 CFR 51.1005(b). For a discussion 
of EPA's interpretation of the requirements of section 188(e), see 
the preamble to the PM2.5 SIP Requirements Rule, 81 FR 
58010, 58094-58097, and the General Preamble Addendum, 59 FR 41998, 
42002.
---------------------------------------------------------------------------

    A state must seek an extension of the Serious area attainment date 
at the same time it submits the Serious area attainment plan, if the 
state cannot demonstrate attainment by the otherwise applicable 
statutory attainment date.\42\
---------------------------------------------------------------------------

    \42\ 40 CFR 51.1005(b)(2).
---------------------------------------------------------------------------

    Under the PM2.5 SIP Requirements Rule, a state seeking 
an extension of the Serious area attainment date under section 188(e) 
must submit a Serious area attainment plan that meets the following 
requirements:
    (1) Base year and attainment projected emissions inventory 
requirements in 40 CFR 51.1008(b);
    (2) the most stringent measure requirement in 40 CFR 
51.1005(b)(1)(iii) and 51.1010(b), and best available control measures 
not previously submitted;
    (3) attainment demonstration and modeling requirements in 40 CFR 
51.1011 and 40 CFR 51.1005(b)(1)(i);
    (4) reasonable further progress requirements in 40 CFR 51.1012;
    (5) quantitative milestone requirements in 40 CFR 51.1013;
    (6) contingency measure requirements in 40 CFR 51.1014; and
    (7) nonattainment new source review plan requirements pursuant to 
40 CFR 51.165.\43\
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    \43\ 40 CFR 51.1005(b)(2). With respect to contingency measures 
and nonattainment new source review plan provisions, the EPA 
interprets section 51.1005(b)(2) to require submission of complete 
plan provisions addressing these requirements but not to require the 
EPA to approve such provisions before granting a section 188(e) 
extension request. 81 FR 58010, 58094-58095.
---------------------------------------------------------------------------

    In addition to establishing specific preconditions for an extension 
of the Serious area attainment date, section 188(e) provides that the 
EPA may consider a number of factors in determining whether to grant an 
extension and the appropriate length of time for any such extension. 
These factors are: (1) The nature and extent of nonattainment in the 
area, (2) the types and numbers of sources or other emitting activities 
in the area (including the influence of uncontrollable natural sources 
and trans-boundary emissions from foreign countries), (3) the 
population exposed to concentrations in excess of the standard in the 
area, (4) the presence and concentrations of potentially toxic 
substances in the mix of particulate emissions in the area, and (5) the 
technological and economic feasibility of various control measures.\44\ 
Notably, neither the statutory requirements nor the discretionary 
factors identified in section 188(e) include the specific ambient air 
quality conditions in section 188(d)(2), which must be met for an area 
to qualify for an extension of a Moderate area attainment date.
---------------------------------------------------------------------------

    \44\ CAA section 188(e).
---------------------------------------------------------------------------

    We evaluate the state's request for an extension of the Serious 
area attainment date in accordance with these statutory criteria and 
regulatory requirements, as described below.
    Step 1: Demonstrate that attainment by the statutory Serious area 
attainment date is impracticable.
    Section 188(e) authorizes the EPA to grant a state request for an 
extension of the Serious area attainment date if, among other things, 
attainment by the date established under section 188(c) would be 
impracticable. In order to demonstrate impracticability, the plan must 
show that the implementation of BACM and BACT (and additional feasible 
measures) on relevant source categories will not bring the area into 
attainment by the statutory Serious area attainment date.\45\ For the 
San Joaquin Valley, the Serious area attainment date for the 2006 
PM2.5 NAAQS under section 188(c)(2) was December 31, 
2019.\46\ BACM, including BACT, is the required level of control for a 
Serious area that must be in place before the Serious area attainment 
date. Therefore, we interpret the Act as requiring that a state provide 
for at least the implementation of BACM, including BACT, before it can 
claim that is impracticable to attain by the statutory deadline. The 
statutory provision for demonstrating impracticability requires that 
the demonstration be based on air quality modeling.\47\
---------------------------------------------------------------------------

    \45\ 81 FR 58010, 58094.
    \46\ Under CAA section 188(c)(2), the attainment date for a 
Serious area ``shall be as expeditiously as practicable but no later 
than the end of the tenth calendar year beginning after the area's 
designation as nonattainment. . . .'' The EPA designated the San 
Joaquin Valley as nonattainment for the 2006 PM2.5 NAAQS 
effective December 14, 2009. 74 FR 58688. Therefore, the latest 
permissible attainment date under section 188(c)(2), for purposes of 
the 2006 PM2.5 NAAQS in this area, is December 31, 2019.
    \47\ CAA section 189(b)(1)(A).
---------------------------------------------------------------------------

    Step 2: Comply with all requirements and commitments in the 
applicable implementation plan.
    A second precondition for an extension of the Serious area 
attainment under section 188(e) is a showing that the state has 
complied with all requirements and commitments pertaining to that area 
in the implementation plan. We interpret this criterion to mean that 
the state has implemented the control measures and commitments in the 
SIP revisions it has submitted to address the applicable requirements 
in CAA sections 172 and 189 for PM2.5 nonattainment areas. 
For a Serious area attainment date extension request being submitted 
simultaneously with the initial Serious area attainment plan for the 
area, the EPA interprets section 188(e) not to require the area to have 
a fully approved Moderate area attainment plan, and to allow for 
extension of the attainment date if the area has complied with all 
Moderate area requirements and commitments pertaining to that area in 
the state's submitted Moderate area implementation plan.\48\ This

[[Page 17387]]

interpretation is based on the plain language of section 188(e), which 
requires the state to comply with all requirements and commitments 
pertaining to the area in the implementation plan.\49\
---------------------------------------------------------------------------

    \48\ 81 FR 58010, 58095.
    \49\ The Ninth Circuit Court of Appeals upheld this 
interpretation of section 188(e) in Vigil v. Leavitt, 366 F.3d 1025, 
amended at 381 F.3d 826 (9th Cir. 2004).
---------------------------------------------------------------------------

    Step 3: Demonstrate the inclusion of the most stringent measures.
    A third precondition for an extension of the Serious area 
attainment under section 188(e) is for the state to demonstrate to the 
satisfaction of the Administrator that the plan for the area includes 
the most stringent measures that are included in the implementation 
plan of any state, or are achieved in practice in any state, and can 
feasibly be implemented in the area. The EPA has defined the term 
``most stringent measure'' (MSM) as ``any permanent and enforceable 
control measure that achieves the most stringent emissions reductions 
in direct PM2.5 emissions and/or emissions of 
PM2.5 plan precursors from among those control measures 
which are either included in the SIP for any other NAAQS, or have been 
achieved in practice in any state, and that can feasibly be implemented 
in the relevant PM2.5 NAAQS nonattainment area.'' \50\ The 
Act does not specify an implementation deadline for MSM, but because 
the clear intent of section 188(e) is to minimize the length of any 
attainment date extension, the EPA has interpreted the Act to require 
implementation of MSM as expeditiously as practicable and no later than 
one year before the extended Serious area attainment date identified by 
the state in its extension request.\51\
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    \50\ 40 CFR 51.1000 and 81 FR 58010, 58096-58097; see also 
General Preamble Addendum, 42010 and 65 FR 19964, 19968 (April 13, 
2000).
    \51\ 81 FR 58010, 58097.
---------------------------------------------------------------------------

    An MSM demonstration must satisfy the requirements of the 
PM2.5 SIP Requirements Rule as described in the preamble to 
the rule, as follows: \52\
---------------------------------------------------------------------------

    \52\ 40 CFR 51.1010(b) and 81 FR 58010, 58095-58097.
---------------------------------------------------------------------------

    (1) Update the emission inventory to identify all sources of direct 
PM2.5 and all PM2.5 precursor emissions in the 
nonattainment area;
    (2) Identify all potential MSM to reduce emissions from sources of 
direct PM2.5 and PM2.5 plan precursors that are 
approved into any state implementation plan or used in practice in any 
state;
    (3) Compare the potential MSM for each relevant source category to 
the measures, if any, already adopted for that source category in the 
nonattainment area to determine whether such potential MSM would 
further reduce emissions and, where the state chooses to reject a 
measure from further consideration, demonstrate that it is not 
technologically or economically feasible to implement the measure in 
whole or in part within five years after the applicable attainment date 
for the area; and
    (4) Adopt and implement all potential MSM identified through this 
process that collectively will achieve attainment as expeditiously as 
practicable and no later than five years after the applicable 
attainment date, except those measures for which the state has provided 
reasoned justification for rejection, based on technological or 
economic feasibility.
    The level of control required under the MSM standard may depend on 
how well other areas have chosen to control their sources. If a source 
category has not been well controlled in other areas, MSM could 
theoretically result in a low level of control. This contrasts with 
BACM and BACT, which represent the ``best'' level of control feasible 
for an area, regardless of whether it has been implemented elsewhere. 
Thus, in some cases the MSM requirement may result in no more controls 
or emission reductions than those that result from implementing BACM 
and BACT. However, given the strategy in the nonattainment provisions 
of the Act to offset longer attainment timeframes with more stringent 
emission control requirements, we interpret the MSM provision so as to 
increase the potential that it will result in additional controls 
beyond the set of measures adopted as BACM and BACT. Accordingly, 
states are required to reanalyze any measures that were rejected during 
the state's BACM and BACT analysis to see if they have become feasible 
in the area given the longer attainment date sought under CAA section 
188(e) and changes that have occurred in the interim that improve the 
feasibility of such measures.\53\ MSM may also involve increasing the 
coverage of measures that were previously adopted as BACM and BACT.\54\
---------------------------------------------------------------------------

    \53\ Id.
    \54\ Id. at 58096.
---------------------------------------------------------------------------

    Notably, the ``to the satisfaction of the Administrator'' qualifier 
on the MSM requirement indicates that Congress granted the EPA 
considerable discretion in determining whether a plan in fact includes 
MSM, recognizing that the overall intent of section 188(e) is that the 
Agency grant as short an extension as practicable, consistent with the 
objective of expeditious attainment of the NAAQS. For this reason, the 
EPA will apply greater scrutiny to the evaluation of MSM for source 
categories that contribute the most to the PM2.5 problem in 
the SJV and less scrutiny to source categories that contribute less to 
the PM2.5 problem.
    Step 4: Demonstrate attainment by the most expeditious alternative 
date practicable.
    Section 189(b)(1)(A) requires that the Serious area plan 
demonstrate attainment, using air quality modeling, by the most 
expeditious date practicable after the statutory Serious area 
attainment date.\55\ Evaluation of a modeled attainment demonstration 
consists of two parts: Evaluation of the technical adequacy of the 
modeling itself and evaluation of the control measures that are relied 
on to demonstrate attainment. The EPA's determination of whether the 
plan provides for attainment by the most expeditious date practicable 
depends on whether the plan provides for implementation of BACM and 
BACT no later than the statutory implementation deadline, MSM as 
expeditiously as practicable and no later than one year before the 
extended attainment date requested by the state, and any other 
technologically and economically feasible measures that will result in 
attainment as expeditiously as practicable.
---------------------------------------------------------------------------

    \55\ Id. at 58097.
---------------------------------------------------------------------------

    Step 5: Apply for an attainment date extension.
    Finally, the state must apply in writing to the EPA for an 
extension of a Serious area attainment date, and this request must 
accompany the modeled attainment demonstration showing attainment by 
the most expeditious alternative date practicable. Additionally, the 
state must provide the public reasonable notice and opportunity for a 
public hearing on the attainment date extension request before 
submitting it to the EPA, in accordance with the requirements for SIP 
revisions in CAA section 110.

IV. Review of the San Joaquin Valley PM2.5 Serious Area Plan and 
Extension Application

A. Emissions Inventory

1. Statutory and Regulatory Requirements
    CAA section 172(c)(3) requires that each SIP include a 
comprehensive, accurate, current inventory of actual emissions from all 
sources of the relevant pollutant or pollutants in the nonattainment 
area. The EPA discussed the emissions inventory requirements that apply 
to PM2.5 nonattainment areas,

[[Page 17388]]

including Serious area requirements, in the PM2.5 SIP 
Requirements Rule and codified these requirements in 40 CFR 
51.1008.\56\ The EPA has also issued guidance concerning emissions 
inventories for PM2.5 nonattainment areas.\57\
---------------------------------------------------------------------------

    \56\ 81 FR 58010, 58078-58079.
    \57\ ``Emissions Inventory Guidance for Implementation of Ozone 
and Particulate Matter National Ambient Air Quality Standards 
(NAAQS) and Regional Haze Regulations,'' U.S. EPA, May 2017 
(``Emissions Inventory Guidance''), available at https://www.epa.gov/air-emissions-inventories/air-emissions-inventory-guidance-implementation-ozone-and-particulate.
---------------------------------------------------------------------------

    The base year emissions inventory should provide a state's best 
estimate of actual emissions from all sources of the relevant 
pollutants in the area, i.e., all emissions that contribute to the 
formation of a particular NAAQS pollutant. For the PM2.5 
NAAQS, the base year inventory must include direct PM2.5 
emissions, separately reported filterable and condensable 
PM2.5 emissions,\58\ and emissions of all chemical 
precursors to the formation of secondary PM2.5: nitrogen 
oxides (NOX), sulfur dioxide (SO2), volatile 
organic compounds (VOC), and ammonia (NH3).\59\ In addition, 
the emissions inventory base year for a Serious PM2.5 
nonattainment area must be one of the three years for which monitored 
data were used to reclassify the area to Serious, or another 
technically appropriate year justified by the state in its Serious area 
SIP submission.\60\
---------------------------------------------------------------------------

    \58\ The Emissions Inventory Guidance identifies the types of 
sources for which the EPA expects states to provide condensable PM 
emission inventories. Emissions Inventory Guidance, section 4.2.1 
(``Condensable PM Emissions''), 63-65.
    \59\ 40 CFR 51.1008.
    \60\ 40 CFR 51.1008(b)(1).
---------------------------------------------------------------------------

    A state's SIP submission must include documentation explaining how 
it calculated emissions data for the inventory. In estimating mobile 
source emissions, a state should use the latest emissions models and 
planning assumptions available at the time the SIP is developed. The 
latest EPA-approved version of California's mobile source emission 
factor model for estimating tailpipe, brake, and tire wear emissions 
from on-road mobile sources that was available during the State's and 
District's development of the SJV PM2.5 Plan was 
EMFAC2014.\61\ Following CARB's submission of the Plan, the EPA 
approved EMFAC2017, the latest revision to this mobile source emissions 
model, and established grace periods during which EMFAC2014 may 
continue to be used for transportation conformity purposes (i.e., new 
regional emissions analyses and CO, PM10, and 
PM2.5 hot-spot analyses).\62\ States are also required to 
use the EPA's ``Compilation of Air Pollutant Emission Factors'' (``AP-
42'') road dust method for calculating re-entrained road dust emissions 
from paved roads.63 64
---------------------------------------------------------------------------

    \61\ 80 FR 77337 (December 14, 2015). EMFAC is short for 
EMission FACtor. The EPA announced the availability of the EMFAC2014 
model, effective on the date of publication in the Federal Register, 
for use in state implementation plan development and transportation 
conformity in California. Upon that action, EMFAC2014 was required 
to be used for all new regional emissions analyses and CO, 
PM10, and PM2.5 hot-spot analyses that were 
started on or after December 14, 2017, which was the end of the 
grace period for using the prior mobile source emissions model, 
EMFAC2011.
    \62\ 84 FR 41717 (August 15, 2019). The grace period for new 
regional emissions analyses begins on August 15, 2019 and ends on 
August 16, 2021, while the grace period for hot-spot analyses begins 
on August 15, 2019 and ends on August 17, 2020. 84 FR 41717, 41720.
    \63\ The EPA released an update to AP-42 in January 2011 that 
revised the equation for estimating paved road dust emissions based 
on an updated data regression that included new emission tests 
results. 76 FR 6328 (February 4, 2011). CARB used the revised 2011 
AP-42 methodology in developing on-road mobile source emissions; see 
https://www.arb.ca.gov/ei/areasrc/fullpdf/full7-9_2016.pdf.
    \64\ AP-42 has been published since 1972 as the primary source 
of the EPA's emission factor information. https://www.epa.gov/air-emissions-factors-and-quantification/ap-42-compilation-air-emissions-factors. It contains emission factors and process 
information for more than 200 air pollution source categories. A 
source category is a specific industry sector or group of similar 
emitting sources. The emission factors have been developed and 
compiled from source test data, material balance studies, and 
engineering estimates.
---------------------------------------------------------------------------

    In addition to the base year inventory submitted to meet the 
requirements of CAA section 172(c)(3), the state must also submit a 
projected attainment year inventory and emissions projections for each 
RFP milestone year.\65\ These future emissions projections are 
necessary components of the attainment demonstration required under CAA 
section 189(a)(1) and (b)(1) and the demonstration of RFP required 
under section 172(c)(2).\66\ Emissions projections for future years 
(which are referred to in the Plan as ``forecasted inventories'') 
should account for, among other things, the ongoing effects of economic 
growth and adopted emissions control requirements. The state's SIP 
submission should include documentation to explain how the emissions 
projections were calculated. Where a state chooses to allow new major 
stationary sources or major modifications to use emission reductions 
credits (ERCs) that were generated through shutdown or curtailed 
emissions units occuring before the base year of an attainment plan, 
the projected emissions inventory used to develop the attainment 
demonstration must explicitly include the emissions from such 
previously shutdown or curtailed emissions units.\67\
---------------------------------------------------------------------------

    \65\ 40 CFR 51.1008 and 51.1012. Also, see Emissions Inventory 
Guidance, section 3 (``SIP Inventory Requirements and 
Recommendations'').
    \66\ 40 CFR 51.1004, 51.1008, 51.1011, and 51.1012.
    \67\ 40 CFR 51.165(a)(3)(ii)(C)(1).
---------------------------------------------------------------------------

2. Summary of State's Submission
    Summaries of the planning emissions inventories for direct 
PM2.5 and PM2.5 precursors (NOX, 
SOX,\68\ VOC,\69\ and ammonia) and the documentation for the 
inventories for the San Joaquin Valley PM2.5 nonattainment 
area are located in Appendix B (``Emissions Inventory'') and Appendix I 
(``New Source Review and Emission Reduction Credits'') of the 2018 
PM2.5 Plan.
---------------------------------------------------------------------------

    \68\ The SJV PM2.5 Plan generally uses ``sulfur 
oxides'' or ``SOX'' in reference to SO2 as a 
precursor to the formation of PM2.5. We use 
SOX and SO2 interchangeably throughout this 
notice.
    \69\ The SJV PM2.5 Plan generally uses ``reactive 
organic gasses'' or ``ROG'' in reference to VOC as a precursor to 
the formation of PM2.5. We use ROG and VOC 
interchangeably throughout this notice.
---------------------------------------------------------------------------

    CARB and District staff worked together to develop the emissions 
inventories for the San Joaquin Valley PM2.5 nonattainment 
area. The District worked with operators of the stationary facilities 
in the nonattainment area to develop the stationary source emissions 
estimates. The responsibility for developing estimates for the area 
sources such as agricultural burning and paved road dust was shared by 
the District and CARB. CARB staff developed the emissions inventories 
for both on-road and non-road mobile sources.\70\
---------------------------------------------------------------------------

    \70\ The EPA regulations refer to ``non-road'' vehicles and 
engines whereas CARB regulations refer to ``Other Mobile Sources'' 
or ``off-road'' vehicles and engines. These terms refer to the same 
types of vehicles and engines. We refer herein to such vehicles and 
engines as ``non-road'' sources.
---------------------------------------------------------------------------

    The Plan includes winter (24-hour) average and annual average daily 
planning inventories for the 2013 base year, which were modeled from 
the 2012 emissions inventory, and estimated emissions for forecasted 
years from 2017 through 2028 for the attainment and RFP demonstrations 
for the 1997, 2006, and 2012 PM2.5 NAAQS.\71\ Today we are 
proposing action on those winter average and annual average emissions 
inventories necessary to support the attainment plan and section 188(e) 
extension

[[Page 17389]]

request for the 2006 PM2.5 NAAQS--i.e., the 2013 base year 
inventory, forecasted inventories for the RFP milestone years of 2017, 
2020, 2023, and 2026, and the forecasted 2024 attainment year 
inventory. Each inventory includes emissions from stationary, area, on-
road, and non-road sources.
---------------------------------------------------------------------------

    \71\ 2018 PM2.5 Plan, App. B, B-18 to B-19. The 
winter average daily planning inventory corresponds to the months of 
November through April, when daily, ambient PM2.5 
concentrations are typically highest. The base year inventory is 
from the California Emissions Inventory Development and Reporting 
System (CEIDARS) and future year inventories were estimated using 
the California Emission Projection Analysis Model (CEPAM), 2016 SIP 
Baseline Emission Projections, version 1.05.
---------------------------------------------------------------------------

    The base year inventories for stationary sources were developed 
using actual emissions reports made by facility operators. The State 
developed the base year emissions inventory for area sources using the 
most recent models and methodologies available at the time the State 
was developing the Plan.\72\ The Plan also includes background, 
methodology, and inventories of condensable and filterable 
PM2.5 emissions from stationary point and non-point 
combustion sources that are expected to generate condensable 
PM2.5.\73\ CARB used EMFAC2014 to estimate on-road motor 
vehicle emissions based on transportation activity data from the 2014 
Regional Transportation Plan (2014 RTP) adopted by the transportation 
planning agencies in the San Joaquin Valley.\74\ Re-entrained paved 
road dust emissions were calculated using a CARB methodology consistent 
with the EPA's AP-42 road dust methodology.\75\
---------------------------------------------------------------------------

    \72\ 2018 PM2.5 Plan, App. B, section B.2 
(``Emissions Inventory Summary and Methodology'').
    \73\ Id. at B-42 to B-44.
    \74\ Id. at B-37.
    \75\ Id. at B-28.
---------------------------------------------------------------------------

    CARB developed the emissions forecasts by applying growth and 
control profiles to the base year inventory. CARB's mobile source 
emissions projections take into account predicted activity rates and 
vehicle fleet turnover by vehicle model year and adopted controls.\76\ 
In addition, the Plan states that the District is providing for use of 
pre-base year ERCs as offsets by accounting for such ERCs in the 
projected 2025 emissions inventory.\77\ The 2018 PM2.5 Plan 
identifies growth factors, control factors, and estimated offset use 
between 2013 and 2025 for direct PM2.5, NOX, 
SOX, and VOC emissions by source category and lists all pre-
base year ERCs issued by the District for PM10, 
NOX, SOX, and VOC emissions, by facility.\78\
---------------------------------------------------------------------------

    \76\ Id. at B-18, B-19.
    \77\ 2018 PM2.5 Plan, App. I, I-1 through I-5.
    \78\ Id. at App. I, Tables I-1 through I-5.
---------------------------------------------------------------------------

    Table 1 provides a summary of the winter (24-hour) average 
inventories in tons per day (tpd) of direct PM2.5 and 
NOX emissions for the 2013 base year. Table 2 provides a 
summary of annual average inventories of direct PM2.5 and 
NOX emissions for the 2013 base year. These annual average 
inventories provide the basis for the control measure analysis and the 
RFP and attainment demonstrations in the SJV PM2.5 Plan.

  Table 1--San Joaquin Valley Winter Average Emissions Inventory for Direct PM2.5 and PM2.5 Precursors for the
                                                 2013 Base Year
                                                      [tpd]
----------------------------------------------------------------------------------------------------------------
                                   Direct PM2.5
            Category                                    NOX             SOX             VOC           Ammonia
----------------------------------------------------------------------------------------------------------------
Stationary Sources..............             8.5            35.0             6.9            86.6            13.9
Area Sources....................            41.4            11.5             0.5           156.8           291.5
On-Road Mobile Sources..........             6.4           188.7             0.6            51.1             4.4
Non-Road Mobile Sources.........             4.4            65.3             0.3            27.4             0.0
                                 -------------------------------------------------------------------------------
    Totals \a\..................            60.8           300.5             8.4           321.9           309.8
----------------------------------------------------------------------------------------------------------------
Source: 2018 PM2.5 Plan, Appendix B, Tables B-1 through B-5.
\a\ Totals reflect disaggregated emissions and may not add exactly as shown here due to rounding.


  Table 2--San Joaquin Valley Annual Average Emissions Inventory for Direct PM2.5 and PM2.5 Precursors for the
                                                 2013 Base Year
                                                      [tpd]
----------------------------------------------------------------------------------------------------------------
                                   Direct PM2.5
            Category                                    NOX             SOX             VOC           Ammonia
----------------------------------------------------------------------------------------------------------------
Stationary Sources..............             8.8            38.6             7.2            87.1            13.9
Area Sources....................            41.5             8.1             0.3           153.4           310.9
On-Road Mobile Sources..........             6.4           183.1             0.6            49.8             4.4
Non-Road Mobile Sources.........             5.8            87.4             0.3            33.8             0.0
                                 -------------------------------------------------------------------------------
    Totals \a\..................            62.5           317.2             8.5           324.1           329.2
----------------------------------------------------------------------------------------------------------------
Source: 2018 PM2.5 Plan, Appendix B, Tables B-1 through B-5.
\a\ Totals reflect disaggregated emissions and may not add exactly as shown here due to rounding.

3. EPA's Evaluation and Proposed Action
    The inventories in the 2018 PM2.5 Plan are based on the 
most current and accurate information available to the State and 
District at the time they were developing the Plan and inventories, 
including the latest version of California's mobile source emissions 
model that had been approved by the EPA at the time, EMFAC2014. The 
inventories comprehensively address all source categories in the San 
Joaquin Valley PM2.5 nonattainment area and are consistent 
with the EPA's inventory guidance.
    In accordance with 40 CFR 51.1008(b)(1), the 2013 base year is one 
of the three years for which monitored data were used for reclassifying 
the San Joaquin Valley to Serious for the 2006 PM2.5 
NAAQS,\79\ and it represents actual annual average emissions of all 
sources within the nonattainment area. Direct PM2.5 and 
PM2.5 precursors are included in the inventories, and 
filterable and condensable direct PM2.5 emissions are 
identified separately.
---------------------------------------------------------------------------

    \79\ 81 FR 2993, 2994.
---------------------------------------------------------------------------

    With respect to future year baseline projections, we have reviewed 
the growth and control factors and find them acceptable and thus 
conclude that

[[Page 17390]]

the future baseline emissions projections in the 2018 PM2.5 
Plan reflect appropriate calculation methods and the latest planning 
assumptions. Also, as a general matter, the EPA will approve a SIP 
submission that takes emissions reduction credit for a control measure 
only where the EPA has approved the measure as part of the SIP. Thus, 
for example, to take credit for the emissions reductions from newly-
adopted or amended District rules for stationary sources, the related 
rules must be approved by the EPA into the SIP. See the EPA's 
``Technical Support Document, General Evaluation, San Joaquin Valley 
PM2.5 Plan for the 2006 PM2.5 NAAQS,'' February 
2020 (``EPA's General Evaluation TSD''). Table III-A of EPA's General 
Evaluation TSD shows District rules with post-2013 compliance dates 
that are reflected in the future year baseline inventories, along with 
information on the EPA's approval of these rules, and shows that 
stationary source emissions reductions assumed by the SJV 
PM2.5 Plan for future years are supported by rules approved 
as part of the California SIP for the San Joaquin Valley. With respect 
to mobile sources, the EPA has taken action in recent years to approve 
CARB mobile source regulations into the state-wide portion of the 
California SIP. We therefore find that the future year baseline 
projections in the 2018 PM2.5 Plan are properly supported by 
SIP-approved stationary and mobile source measures.\80\
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    \80\ The future year emissions projections in the SJV 
PM2.5 Plan assume implementation of CARB's Zero Emissions 
Vehicle (ZEV) sales mandate and greenhouse gas (GHG) standards. On 
September 27, 2019, the U.S. Department of Transportation and the 
EPA issued a notice of final rulemaking for the Safer Affordable 
Fuel-Efficient (SAFE) Vehicles Rule Part One: One National Program 
that, among other things, withdrew the EPA's 2013 waiver of 
preemption for the ZEV sales mandate and GHG standards. 84 FR 51310. 
See also proposed SAFE rule at 83 FR 42986 (August 24, 2018). 
However, the agencies' final rule withdrawing the 2013 waiver did 
not include final action on the federal fuel economy and GHG vehicle 
emissions standards from the SAFE proposal. If the fuel economy and 
GHG standards are finalized prior to our final rulemaking on the SJV 
PM2.5 Plan, we will evaluate and address, as appropriate, 
the impact of the SAFE action on our proposed action.
---------------------------------------------------------------------------

    For these reasons, we are proposing to approve the 2013 base year 
emissions inventory in the 2018 PM2.5 Plan as meeting the 
requirements of CAA section 172(c)(3) and 40 CFR 51.1008. We are also 
proposing to find that the forecasted inventories in the Plan provide 
an adequate basis for the BACM, MSM, RFP, and attainment demonstrations 
in the SJV PM2.5 Plan.

B. PM2.5 Precursors

1. Statutory and Regulatory Requirements
    The composition of PM2.5 is complex and highly variable 
due in part to the large contribution of secondary PM2.5 to 
total fine particle mass in most locations, and to the complexity of 
secondary particle formation processes. A large number of possible 
chemical reactions, often non-linear in nature, can convert gaseous 
SO2, NOX, VOC, and ammonia to PM2.5, 
making them precursors to PM2.5.\81\ Formation of secondary 
PM2.5 may also depend on atmospheric conditions, including 
solar radiation, temperature, and relative humidity, and the 
interactions of precursors with preexisting particles and with cloud or 
fog droplets.\82\
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    \81\ ``Air Quality Criteria for Particulate Matter'' (EPA/600/P-
99/002aF), EPA, October 2004, Ch. 3.
    \82\ ``Regulatory Impact Analysis for the Final Revisions to the 
National Ambient Air Quality Standards for Particulate Matter'' 
(EPA/452/R-12-005), EPA, December 2012), 2-1.
---------------------------------------------------------------------------

    Under subpart 4 of part D, title I of the CAA and the 
PM2.5 SIP Requirements Rule, each state containing a 
PM2.5 nonattainment area must evaluate all PM2.5 
precursors for regulation unless, for any given PM2.5 
precursor, the state demonstrates to the Administrator's satisfaction 
that such precursor does not contribute significantly to 
PM2.5 levels that exceed the NAAQS in the nonattainment 
area.\83\ The provisions of subpart 4 do not define the term 
``precursor'' for purposes of PM2.5, nor do they explicitly 
require the control of any specifically identified PM2.5 
precursor. The statutory definition of ``air pollutant,'' however, 
provides that the term ``includes any precursors to the formation of 
any air pollutant, to the extent the Administrator has identified such 
precursor or precursors for the particular purpose for which the term 
`air pollutant' is used.'' \84\ The EPA has identified SO2, 
NOX, VOC, and ammonia as precursors to the formation of 
PM2.5.\85\ Accordingly, the attainment plan requirements of 
subpart 4 apply to emissions of all four precursor pollutants and 
direct PM2.5 from all types of stationary, area, and mobile 
sources, except as otherwise provided in the Act (e.g., CAA section 
189(e)).
---------------------------------------------------------------------------

    \83\ 81 FR 58010, 58017-58020.
    \84\ CAA section 302(g).
    \85\ 81 FR 58010, 58015.
---------------------------------------------------------------------------

    Section 189(e) of the Act requires that the control requirements 
for major stationary sources of direct PM10 also apply to 
major stationary sources of PM10 precursors, except where 
the Administrator determines that such sources do not contribute 
significantly to PM10 levels that exceed the standard in the 
area. Section 189(e) contains the only express exception to the control 
requirements under subpart 4 [e.g., requirements for reasonably 
available control measures (RACM) and reasonably available control 
technology (RACT), BACM and BACT, MSM, and NSR] for sources of direct 
PM2.5 and PM2.5 precursor emissions. Although 
section 189(e) explicitly addresses only major stationary sources, the 
EPA interprets the Act as authorizing it also to determine, under 
appropriate circumstances, that regulation of specific PM2.5 
precursors from other source categories in a given nonattainment area 
is not necessary.\86\ For example, under the EPA's longstanding 
interpretation of the control requirements that apply to stationary, 
area, and mobile sources of PM10 precursors in the 
nonattainment area under CAA section 172(c)(1) and subpart 4,\87\ a 
state may demonstrate in a SIP submission that control of a certain 
precursor pollutant is not necessary in light of its insignificant 
contribution to ambient PM10 levels in the nonattainment 
area.\88\
---------------------------------------------------------------------------

    \86\ Id. at 58018-58019.
    \87\ General Preamble, 57 FR 13498, 13539-42.
    \88\ Courts have upheld this approach to the requirements of 
subpart 4 for PM10. See, e.g., Assoc. of Irritated 
Residents v. EPA, et al., 423 F.3d 989 (9th Cir. 2005).
---------------------------------------------------------------------------

    Under the PM2.5 SIP Requirements Rule, a state may elect 
to submit to the EPA a ``comprehensive precursor demonstration'' for a 
specific nonattainment area to show that emissions of a particular 
precursor from all existing sources located in the nonattainment area 
do not contribute significantly to PM2.5 levels that exceed 
the standard in the area.\89\ If the EPA determines that the 
contribution of the precursor to PM2.5 levels in the area is 
not significant and approves the demonstration, the state is not 
required to control emissions of the relevant precursor from existing 
sources in the attainment plan.\90\
---------------------------------------------------------------------------

    \89\ 40 CFR 51.1006(a)(1).
    \90\ Id.
---------------------------------------------------------------------------

    In addition, in May 2019, the EPA issued the ``PM2.5 
Precursor Demonstration Guidance'' (``PM2.5 Precursor 
Guidance''), which provides recommendations to states for analyzing 
nonattainment area PM2.5 emissions and developing such 
optional precursor demonstrations, consistent with the PM2.5 
SIP Requirements Rule.\91\ The

[[Page 17391]]

PM2.5 Precursor Guidance builds upon the draft version of 
the guidance, released on November 17, 2016 (``Draft PM2.5 
Precursor Guidance''), which CARB referenced in developing its 
precursor demonstration in the SJV PM2.5 Plan.\92\ The EPA's 
recommendations in the PM2.5 Precursor Guidance are 
generally consistent with those in the Draft PM2.5 Precursor 
Guidance, with some exceptions, including that the EPA's recommended 
contribution threshold for the 24-hour PM2.5 NAAQS changed 
from 1.3 [micro]g/m\3\ in the draft guidance to 1.5 [micro]g/m\3\ in 
the final guidance.
---------------------------------------------------------------------------

    \91\ ``PM2.5 Precursor Demonstration Guidance,'' EPA-
454/R-19-004, May 2019, including Memo dated May 30, 2019 from Scott 
Mathias, Acting Director, Air Quality Policy Division and Richard 
Wayland, Director, Air Quality Assessment Division, Office of Air 
Quality Planning and Standards (OAQPS), EPA to Regional Air Division 
Directors, Regions 1-10, EPA.
    \92\ ``PM2.5 Precursor Demonstration Guidance, Draft 
for Public Review and Comments,'' EPA-454/P-16-001, November 17, 
2016, including Memo dated November 17, 2016 from Stephen D. Page, 
Director, OAQPS, EPA to Regional Air Division Directors, Regions 1-
10, EPA.
---------------------------------------------------------------------------

    We are evaluating the SJV PM2.5 Plan in accordance with 
the presumption embodied within subpart 4 that all PM2.5 
precursors must be addressed in the State's evaluation of potential 
control measures, unless the State adequately demonstrates that 
emissions of a particular precursor or precursors do not contribute 
significantly to ambient PM2.5 levels that exceed the 
PM2.5 NAAQS in the nonattainment area. In reviewing any 
determination by the State to exclude a PM2.5 precursor from 
the required evaluation of potential control measures, we consider both 
the magnitude of the precursor's contribution to ambient 
PM2.5 concentrations in the nonattainment area and the 
sensitivity of ambient PM2.5 concentrations in the area to 
reductions in emissions of that precursor.\93\
---------------------------------------------------------------------------

    \93\ 40 CFR 51.1006(a)(1)(i) and (ii).
---------------------------------------------------------------------------

2. Summary of State's Submission
    The State presents a brief summary of its PM2.5 
precursor analysis in Chapter 6 of the 2018 PM2.5 Plan and 
the full precursor demonstration in Appendix G of the 2018 
PM2.5 Plan.\94\ CARB also provided clarifying information on 
its precursor assessment, including an Attachment A to its letter 
transmitting the SJV PM2.5 Plan to the EPA \95\ and further 
clarifications in three email transmittals.\96\
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    \94\ A copy of the contents of App. G appears in the CARB Staff 
Report, App. C4 (``Precursor Demonstrations for Ammonia, 
SOX, and ROG'').
    \95\ Letter dated May 9, 2019, from Richard Corey, Executive 
Officer, CARB, to Michael Stoker, Regional Administrator, EPA Region 
IX, Attachment A (``Clarifying information for the San Joaquin 
Valley 2018 Plan regarding model sensitivity related to ammonia and 
ammonia controls'').
    \96\ Email dated June 20, 2019, ``RE: SJV model disbenefit from 
SOX reduction,'' from Jeremy Avise, CARB, to Scott 
Bohning, EPA Region IX, with attachment (``CARB's June 2019 
Precursor Clarification''); email dated September 19, 2019, ``FW: 
SJV species responses,'' from Jeremy Avise, CARB, to Scott Bohning, 
EPA Region IX, with attachments (``CARB's September 2019 Precursor 
Clarification''); and email dated October 18, 2019, from Laura Carr, 
CARB to Scott Bohning, Jeanhee Hong, and Rory Mays, EPA Region IX, 
with attachment ``Clarifying Information on Ammonia'' (``CARB's 
October 2019 Precursor Clarification'').
---------------------------------------------------------------------------

    The Plan provides both concentration-based and sensitivity-based 
analyses of precursor contributions to ambient PM2.5 
concentrations in the San Joaquin Valley. These analyses led the State 
to conclude that direct PM2.5 and NOX emissions 
contribute significantly to ambient PM2.5 levels that exceed 
the PM2.5 NAAQS in the San Joaquin Valley while ammonia, 
SOX, and VOC do not contribute significantly to such 
exceedances, as discussed below.\97\ We summarize the State's analysis 
and conclusions below. For a more detailed summary of the precursor 
demonstration in the Plan, please refer to the EPA's ``Technical 
Support Document, EPA Evaluation of PM2.5 Precursor 
Demonstration, San Joaquin Valley PM2.5 Plan for the 2006 
PM2.5 NAAQS,'' February 2020 (``EPA's PM2.5 
Precursor TSD'').
---------------------------------------------------------------------------

    \97\ Direct PM2.5 emissions are considered a primary 
source of ambient PM2.5 (i.e., no further formation in 
the atmosphere is required), and therefore is not considered a 
precursor pollutant under subpart 4, which may differ from a more 
generalized understanding of what contributes to ambient 
PM2.5.
---------------------------------------------------------------------------

    For direct PM2.5 and NOX, the State modeled 
the sensitivity of ambient PM2.5 in the San Joaquin Valley 
to a 30 percent (%) reduction in anthropogenic emissions of each 
pollutant in 2013, 2020, and 2024.\98\ The State concluded that direct 
PM2.5 and NOX emissions reductions will continue 
to have a significant impact on annual and 24-hour PM2.5 
design values in the San Joaquin Valley, with NOX reductions 
being particularly important.\99\ Consistent with this conclusion, the 
State focused the control strategy and attainment demonstration on 
these two pollutants, as described in section IV.D of this preamble.
---------------------------------------------------------------------------

    \98\ SJV PM2.5 Plan, Ch. 6, 6-11 to 6-12. CARB 
modeled the impacts of both NOX reductions and direct 
PM2.5 reductions but the direct PM2.5 results 
were used only as a point of comparison, as direct PM2.5 
emissions must be regulated in all PM2.5 nonattainment 
areas.
    \99\ Id. Ch. 6, 6-12; and 2018 PM2.5 Plan, App. G, 2. 
CARB presents its sensitivity analysis for emission reductions in 
direct PM2.5 and NOX in the Plan's attainment 
demonstration appendix. 2018 PM2.5 Plan, App. K, Table 46 
(annual average design values) and Table 50 (24-hour average design 
values).
---------------------------------------------------------------------------

    For ammonia, SOX, and VOC, CARB assessed the 2015 annual 
average concentration of each precursor in ambient PM2.5 at 
Bakersfield, for which the necessary speciated PM2.5 data is 
available and where the highest PM2.5 design values have 
been recorded in most years, and compared those concentrations to the 
recommended annual average contribution threshold of 0.2 [micro]g/m\3\ 
from the Draft PM2.5 Precursor Guidance, which was available 
at the time the State developed the SIP.\100\ The contributions of 
ammonia, SOX, and VOC were 5.2 [micro]g/m\3\, 1.6 [micro]g/
m\3\ and 6.2 [micro]g/m\3\, respectively.
---------------------------------------------------------------------------

    \100\ SJV PM2.5 Plan, App. G, 3. The Plan does not 
present a concentration-based analysis for the 24-hour average 
concentrations in the San Joaquin Valley. Instead, CARB relied on 
the annual average concentration based analysis as an interim step 
to the sensitivity-based analysis, for which CARB assessed the 
sensitivity of both 24-hour average and annual average ambient 
PM2.5 concentrations to precursor emission reductions. 
Separately, the Plan presents a graphical representation of annual 
average ambient PM2.5 components (i.e., crustal 
particulate matter, elemental carbon, organic matter, ammonium 
sulfate, and ammonium nitrate) for 2011-2013 for Bakersfield, 
Fresno, and Modesto. SJV PM2.5 Plan, Ch. 3, 3-3 to 3-4.
---------------------------------------------------------------------------

    Given that these levels are well above the EPA's recommended 
contribution threshold in the Draft PM2.5 Precursor 
Guidance, CARB then modeled the sensitivity of ambient PM2.5 
in the San Joaquin Valley to 30% and 70% reductions in anthropogenic 
emissions of each precursor pollutant in 2013 (the Plan's base year), 
2020 (the modeled attainment year for the 1997 PM2.5 NAAQS), 
and 2024 (the modeled attainment year for the 2006 PM2.5 
NAAQS).\101\ CARB supplemented the sensitivity analysis with 
consideration of additional information, including factors identified 
in the Draft PM2.5 Precursor Guidance, such as emission 
trends, the appropriateness of future year versus base year 
sensitivity, available emission controls, and the severity of 
nonattainment.\102\ The final version of the PM2.5 Precursor 
Guidance confirms the relevance of these factors in a sensitivity 
analysis.\103\
---------------------------------------------------------------------------

    \101\ SJV PM2.5 Plan, Ch. 6, 6-11 to 6-12.
    \102\ Id. at App. G, 5.
    \103\ PM2.5 Precursor Guidance, 18-19 (consideration 
of additional information), 31 (available emission controls), and 
35-36 (appropriateness of future year versus base year sensitivity).
---------------------------------------------------------------------------

    The State's sensitivity-based analysis used the same modeling 
platform as that used for the Plan's attainment demonstration. The 
State modeled the sensitivity of ambient PM2.5 
concentrations in San Joaquin Valley to 30% and 70% emission reductions 
in 2013, 2020, and 2024 for each of ammonia, SOX, and VOC. 
The State estimated base case (2013, 2020, and 2024) design values for 
PM2.5 using Relative Response Factors and

[[Page 17392]]

calculated the ammonia precursor contribution for a given year and for 
each sensitivity scenario (30% and 70% emissions reductions) as the 
difference between its base case design value and the design value for 
each sensitivity scenario.\104\
---------------------------------------------------------------------------

    \104\ This procedure is the procedure recommended by the EPA. 
PM2.5 Precursor Guidance, 37.
---------------------------------------------------------------------------

    We summarize the State's sensitivity-based analysis and additional 
information in the sections that follow for ammonia, SOX, 
and VOC.
a. Ammonia
    For ammonia, the State compared the 24-hour precursor contributions 
to 1.3 [micro]g/m\3\, the recommended contribution threshold in the 
Draft PM2.5 Precursor Guidance. For a modeled 30% ammonia 
emission reduction, the ambient PM2.5 responses in 2013 
ranged from 0.9 to 3.3 [micro]g/m\3\ across 15 monitoring sites, with a 
majority of sites above the 1.3 [micro]g/m\3\ contribution threshold 
(and also above the 1.5 [micro]g/m\3\ contribution threshold in the 
final PM2.5 Precursor Guidance), whereas the 
PM2.5 responses in 2024 were all below both recommended 
thresholds. For a modeled 70% ammonia emission reduction, the ambient 
PM2.5 responses in 2013 ranged from 3.5 to 12.4 [micro]g/
m\3\, with all monitoring sites above the 1.3 [micro]g/m\3\ threshold 
(and above the 1.5 [micro]g/m\3\ threshold), and the PM2.5 
responses in 2024 ranged from 1.2 to 3.0 [micro]g/m\3\, with most sites 
above both recommended thresholds. For further detail, please see the 
EPA's PM2.5 Precursor TSD, Table 2, and the 2018 
PM2.5 Plan, Appendix G, Tables 2, 3, 5, and 7.
    The State bases its ammonia precursor determination on the 
sensitivity analysis for the 2024 attainment year with a 30% ammonia 
emission reduction. These respectively reflect its assessment of 
research studies and the Plan's projected emission reductions, and on 
its assessment of available emission controls. As explained in the 
PM2.5 Precursor Guidance, precursor responses may be above 
the recommend contribution threshold and yet not contribute 
significantly to levels that exceed the standard in the area. 
Therefore, as recommended by the EPA, the State considered additional 
information to consider whether its identified PM2.5 
responses constituted a significant contribution to ambient 
PM2.5 in the San Joaquin Valley. The additional information 
included research studies, emission trends, and information to support 
the State's conclusion that a 30% ammonia emission reduction 
represented a reasonable upper bound on the ammonia emission reductions 
to model in estimating its contribution to ambient PM2.5 
levels. We summarize this additional information below and provide a 
more detailed evaluation in the EPA's PM2.5 Precursor TSD.
    The State describes previous research that supports its finding 
that ammonium nitrate PM2.5 formation in the San Joaquin 
Valley is NOX-limited rather than ammonia-limited.\105\ 
Essentially, ammonia is so abundant that even with large ammonia 
emission reductions there would still be enough ammonia to combine with 
the available NOX to readily form particulate ammonium 
nitrate. Therefore, ammonia emissions reductions would lead to only 
small decreases in PM2.5 concentrations. In contrast, 
because emissions of NOX are less abundant (i.e., more 
limited relative to emissions of ammonia after normalizing for their 
differing molecular weights), the PM2.5 concentrations in 
the atmosphere are more responsive to reductions in NOX than 
to reductions of ammonia. Hence, the area is considered NOX-
limited. The State points to the conclusions of Lurmann et al. based on 
ambient measurements during the winter 2000-2001 CRPAQS (California 
Regional Particulate Air Quality Study) intensive field study.\106\ 
That study found that most areas of the San Joaquin Valley were 
NOX-limited with respect to ammonium nitrate formation. And 
since that time, large additional NOX emission reductions 
have occurred, which would increase the degree to which ammonium 
nitrate formation in the San Joaquin Valley is NOX-limited. 
Based on more recent aircraft-borne measurements during the 2013 
DISCOVER-AQ campaign,\107\ the State similarly concluded that ammonium 
nitrate formation is NOX-limited based on the large amount 
of ``excess ammonia,'' which is defined as the amount of measured 
ammonia left over if all the nitrate and sulfate present were to 
combine with available ammonia to form particulate.\108\ The CARB Staff 
Report describes these conclusions in more detail and lists results 
from multiple other recent studies with similar conclusions.\109\
---------------------------------------------------------------------------

    \105\ 2018 PM2.5 Plan, App. G, G-9 to G-10; CARB 
Staff Report, App. C, 12-15; and Attachment A to CARB's submittal 
letter of May 9, 2019.
    \106\ Frederick W. Lurmann, Steven G. Brown, Michael C. 
McCarthy, and Paul T. Roberts, ``Processes Influencing Secondary 
Aerosol Formation in the San Joaquin Valley during Winter,'' Journal 
of the Air & Waste Management Association, (2006), 56:12, 1679-1693, 
DOI: 10.1080/10473289.2006.10464573.
    \107\ ``Deriving Information on Surface conditions from COlumn 
and VERtically Resolved Observations Relevant to Air Quality'', 
https://www.nasa.gov/mission_pages/discover-aq/index.html.
    \108\ 2018 PM2.5 Plan, App. G, Figure 2.
    \109\ CARB Staff Report, App. C, 12.
---------------------------------------------------------------------------

    Regarding emission trends, the CARB Staff Report presents an 
emission inventory-based argument on the relative insensitivity of 
PM2.5 to ammonia reductions.\110\ CARB compared the size of 
the ammonia and NOX emission inventories in tons per day, 
after normalizing for their differing molecular weights, and found that 
ammonia was roughly three times as abundant as NOX in 2013 
and is projected to be about six times as abundant in 2025, due to the 
continuing decline in NOX emissions (while ammonia emissions 
are generally constant into the future).\111\ While the State 
recognized that this is only a ``first-level assessment,'' it provides 
additional support for the State's conclusion that NOX, and 
not ammonia, is the limiting precursor for ammonium nitrate formation, 
and that the ammonium nitrate portion of ambient PM2.5 would 
be expected to be relatively insensitive to ammonia emission 
reductions. This is also consistent with the ammonia sensitivity 
modeling for the San Joaquin Valley, which showed that PM2.5 
concentrations will be less sensitive to ammonia reductions as 
NOX emissions go down in the future (i.e., the 
PM2.5 impacts were much smaller in the 2024 future modeled 
case compared to the 2013 base year).
---------------------------------------------------------------------------

    \110\ Id. App. C, 15.
    \111\ Annual average ammonia emissions are projected to decrease 
4.6 tpd (1.4%) from 2013 to 2024. 2018 PM2.5 Plan, App. 
B, Table B-5.
---------------------------------------------------------------------------

    The State finds that NOX emissions in the San Joaquin 
Valley are projected to decrease by 53% from 2013 to 2024 while ammonia 
emissions are projected to remain relatively flat, thereby increasing 
the relative abundance of ammonia.\112\ Based on the Plan's emission 
reduction projections combined with the research study conclusions, the 
State relies on the modeled responses for the 2024 future year, rather 
than the 2013 base year, stating that the future year NOX 
emissions are more representative of San Joaquin Valley emission 
conditions.\113\ The State references the Draft PM2.5 
Precursor Guidance, which notes that it may be appropriate to model 
future conditions that are more representative of current atmospheric 
conditions and those conditions expected closer to the attainment date. 
The State concludes states that this in

[[Page 17393]]

fact applies to the San Joaquin Valley.\114\
---------------------------------------------------------------------------

    \112\ 2018 PM2.5 Plan, App. G, 8-9.
    \113\ Id. App. G, 9.
    \114\ Id (referencing Draft PM2.5 Precursor Guidance, 
33). See also PM2.5 Precursor Guidance, 35.
---------------------------------------------------------------------------

    With respect to the State's selection of 30% as an upper bound on 
the ammonia reductions to model, the State described its review of the 
most important ammonia source categories in the San Joaquin Valley, 
existing control measures that affect ammonia emissions from these 
sources, additional mitigation options for these sources, and 
information provided in the PM2.5 Precursor Guidance about 
ammonia reductions achieved nationwide from 2011 to 2017.\115\ The 
primary sources of ammonia emissions identified in the 2018 
PM2.5 Plan are: (1) Confined animal facilities (CAFs), (2) 
agricultural fertilizer, (3) biosolids, animal manure, and poultry 
litter operations, and (4) organic material composting operations.\116\ 
CAFs are subject to District Rule 4570; biosolids, animal manure, and 
poultry litter operations are subject to District Rule 4565; and 
organic material composting operations are subject to District Rule 
4566. Although these District rules explicitly apply only to VOC 
emissions from these sources, the State concludes that these rules also 
reduce ammonia emissions. Appendix C of the 2018 PM2.5 Plan 
cites a number of scientific studies that address the correlation 
between VOC and ammonia emissions from these emission sources.\117\ 
Based on these evaluations, the State concludes that ammonia control 
measures achieving even the low end of the range (30%) are not feasible 
for implementation in the San Joaquin Valley and that it is therefore 
reasonable to treat a 30% ammonia reduction as an upper bound for 
modeling in the precursor demonstration.
---------------------------------------------------------------------------

    \115\ 2018 PM2.5 Plan, App. G, 13 and App. C, section 
C-25 and email dated October 18, 2019, from Laura Carr, CARB to 
Scott Bohning, EPA Region IX, attaching document entitled 
``Clarifying Information on Ammonia.''
    \116\ 2018 PM2.5 Plan, App. C, section C-25.
    \117\ Id. at C-314 and following.
---------------------------------------------------------------------------

    In sum, the State's sensitivity analysis presents a range of 
PM2.5 responses to ammonia emission reductions depending on 
base year versus future year and depending on the scale of emission 
reductions that may be possible. The Plan provides the State's bases 
for finding that the sensitivity result for 2024 better represents 
conditions in the San Joaquin Valley than the 2013 base year and for 
finding a 30% ammonia reduction to be a reasonable upper bound for 
modeled ammonia emission reductions in assessing the ammonia 
contribution. Based on these analyses, the State concludes that ammonia 
does not contribute significantly to levels above the 2006 
PM2.5 NAAQS in the San Joaquin Valley.
b. SOX
    For SOX, the State compared the 24-hour precursor 
contributions to the recommended draft contribution threshold of 1.3 
[micro]g/m\3\ in the Draft PM2.5 Precursor Guidance. For 
modeled SOX emission reductions of 30% and 70%, the ambient 
PM2.5 responses in 2013 ranged from -1.4 to +0.5 [micro]g/
m\3\ across 15 monitoring sites, which all fall below the 1.3 [micro]g/
m\3\ draft contribution threshold, and hence also below the 
contribution threshold of 1.5 [micro]g/m\3\ in the final version of the 
PM2.5 Precursor Guidance. The response was below zero at 
most monitoring sites, indicating an increase, rather than decrease, in 
ambient PM2.5 in response to SOX emission 
reductions (i.e., a disbenefit). Only the Stockton and Manteca sites 
had slightly positive responses to 30 and 70% emission reductions, and 
the Tranquillity site also had a slightly positive response only to a 
30% reduction. For 2024, the response ranged from -0.3 [micro]g/m\3\ to 
+0.3 [micro]g/m\3\; these are also all below the contribution 
threshold, with most sites showing a disbenefit from SOX 
reductions. For further detail, please see EPA's PM2.5 
Precursor TSD, Table 3, and the 2018 PM2.5 Plan, Appendix G, 
Tables 8 and 9.
    CARB also included additional information regarding emission trends 
and an evaluation of the SOX emission reduction disbenefit. 
We summarize this additional information below and provide a more 
detailed evaluation in the EPA's PM2.5 Precursor TSD.
    In terms of emission trends, the State found that SOX 
emissions decreased from 2013 to 2014 and then very gradually rise to 
8.0 tpd in 2024.\118\ On the basis of SOX emissions being 
very similar in 2020 and 2024 (7.8 tpd and 8.0 tpd, respectively), the 
State concluded that the 2020 and 2024 sensitivity results were 
redundant. Comparing the ambient responses in 2013 and 2024, the State 
found that the responses were slightly less negative or, for a small 
number of sites, slightly more positive in 2024, but still no more than 
0.6 [micro]g/m\3\ in response to a 70% SOX emission 
reduction. This supports the State's conclusion as to the overall 
disbenefit of reducing SOX emissions.
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    \118\ 2018 PM2.5 Plan, App. G, Figure 4.
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    To explain the SOX emission reduction disbenefit, CARB 
refers to the non-linearity of inorganic aerosol thermodynamics, as 
described in a study by West et al.\119\ That paper discusses how, 
under certain conditions, reducing SOX could free ammonia to 
combine with nitrate, increasing overall PM2.5 mass. To 
investigate this issue further, CARB conducted simulations with the 
ISORROPIA inorganic aerosol thermodynamic equilibrium model used within 
the Community Multiscale Air Quality (CMAQ) model and provided 
clarifications to the EPA.\120\ In essence, CARB states that for some 
conditions typical of San Joaquin Valley, ISORROPIA switches to a 
different chemical regime in which the disbenefit occurs. CARB states 
that it is not known how well this model behavior reflects the actual 
atmosphere, but CARB accepts the results because is it a well-known and 
widely used chemical model.
---------------------------------------------------------------------------

    \119\ 2018 PM2.5 Plan, App. K, section 5.6 
(``PM2.5 Precursor Sensitivity Analysis''); and West, 
J.J., Ansari, A.S., Pandis, S.N., 1999, Marginal PM2.5: 
Nonlinear aerosol mass response to sulfate reductions in the eastern 
United States, Journal of the Air & Waste Management Association, 
49, 1415-1424. https://doi.org/10.1080/10473289.1999.10463973.
    \120\ CARB's June 2019 Precursor Clarification.
---------------------------------------------------------------------------

    Based on the small and mostly negative modeled response of ambient 
PM2.5 to SOX emission reductions, and based on 
its scientific understanding of sulfate interactions with other 
molecules in the air, the State concludes that SOX does not 
contribute significantly to ambient PM2.5 levels that exceed 
the 2006 PM2.5 NAAQS in the San Joaquin Valley.
c. VOC
    For VOC, CARB compared the 24-hour precursor contributions to the 
EPA's recommended draft contribution threshold of 1.3 [micro]g/m\3\. 
For a modeled 30% VOC emission reduction, the ambient PM2.5 
responses in 2013 ranged from 0.1 to 1.9 [micro]g/m\3\ across 15 
monitoring sites, with two sites above the 1.3 [micro]g/m\3\ draft 
contribution threshold.\121\ The PM2.5 responses to a 70% 
VOC emission reduction in 2013 ranged from 0.2 [micro]g/m\3\ to 4.8 
[micro]g/m\3\, including responses above the 1.3 [micro]g/m\3\ draft 
contribution threshold at a majority of sites. For a modeled 30% VOC 
emission reduction, the ambient PM2.5 responses in 2024 
ranged from -0.4 to 0.0 [micro]g/m\3\, with all monitoring sites below 
the 1.3 [micro]g/m\3\ draft

[[Page 17394]]

contribution threshold, and hence also below the contribution threshold 
of 1.5 [micro]g/m\3\ that was finalized the PM2.5 SIP 
Requirements Rule. The PM2.5 responses to a 70% VOC emission 
reduction in 2024 ranged from -1.0 to 0.0 [micro]g/m\3\, with all 
monitoring sites below the 1.3 [micro]g/m\3\ draft contribution 
threshold. In other words, CARB models a decrease in ambient 
PM2.5 levels in 2013 in response to either a 30% or 70% VOC 
emission reduction, whereas CARB models an increase in ambient 
PM2.5 levels in 2024 in response to either a 30% or 70% 
reduction in VOC emissions, i.e., a disbenefit. For further detail, 
please see EPA's PM2.5 Precursor TSD, Table 4, and the 2018 
PM2.5 Plan, Appendix G, Tables 10, 11, 13, and 15.
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    \121\ We note that one site (Visalia) has a modeled response 
above the EPA's final recommended contribution threshold of 1.5 
[micro]g/m\3\ and one additional site (Bakersfield-California 
Avenue) has a modeled response below the 1.5 [micro]g/m\3\ threshold 
but above the EPA's draft threshold of 1.3 [micro]g/m\3\.
---------------------------------------------------------------------------

    CARB then considered additional information to consider whether 
these PM2.5 responses constituted a significant contribution 
to ambient PM2.5 in the San Joaquin Valley, including 
emission trends and an assessment of the modeled disbenefit of VOC 
emission reductions in 2024. CARB bases its precursor determination on 
sensitivity analysis for the 2024 attainment year, reflecting its 
assessment of the Plan's projected emission reductions. We summarize 
this additional information below and present greater detail in the 
EPA's PM2.5 Precursor TSD.
    Regarding emission trends, CARB found that VOC emissions would 
decrease approximately 30 tpd (or 9%) from 2013 to 2024.\122\ The State 
concludes that the formation of ambient PM2.5 from VOC may 
therefore differ in base and future years and that the sensitivity 
analysis for 2013 is not representative of current or future 
conditions.
---------------------------------------------------------------------------

    \122\ 2018 PM2.5 Plan, App. G, 19 and Figure 5.
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    CARB explained the modeled disbenefit of VOC reductions as follows: 
Emissions of VOC and NOX react in the atmosphere to form 
organic nitrate species, such as peroxyacetyl nitrate (PAN), meaning 
that some portion of the NOX emissions is not available to 
react with ammonia to form ammonium nitrate. In other words, VOC 
emissions are a ``sink'' for NOX emissions. Reducing VOC 
emissions therefore reduces the formation of organic nitrates, so the 
sink is smaller and nitrate molecules are freed to react with ammonia 
to form particulate ammonium nitrate.\123\ The State further explored 
the VOC disbenefit based on a 2016 CARB modeling assessment provided in 
Appendix A (``Air Quality Modeling'') of the ``2016 Moderate Area Plan 
for the 2012 PM2.5 Standard'' for the San Joaquin Valley 
(``2016 PM2.5 Plan''), which CARB submitted to the EPA as a 
SIP revision on May 10, 2019.\124\
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    \123\ 2018 PM2.5 Plan, App. K, 72 (citing Meng, Z., 
D. Dabdub, D., Seinfeld, J.H., Chemical Coupling Between Atmospheric 
Ozone and Particulate Matter, Science 277, 116 (1997). DOI: 10.1126/
science.277.5322.116).
    \124\ 2016 PM2.5 Plan, App. A, A-57. See also 2018 
PM2.5 Plan, App. K, section 5.6 (``PM2.5 
Precursor Sensitivity Analysis''), 71-72.
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    Based on its sensitivity-based analysis of VOC emission reductions 
in the 2013 base and 2024 future years, VOC emission trends, and the 
scientific understanding of atmospheric VOC chemistry in the San 
Joaquin Valley, CARB concludes that VOC emissions do not contribute 
significantly to PM2.5 levels that exceed the 2006 
PM2.5 NAAQS in the San Joaquin Valley.
3. EPA's Evaluation and Proposed Action
    The EPA has evaluated the State's precursor demonstration 
consistent with the PM2.5 SIP Requirements Rule and the 
recommendations in the PM2.5 Precursor Guidance. Based on 
this evaluation, the EPA agrees that NOX emissions 
contribute significantly to ambient PM2.5 levels that exceed 
the 2006 PM2.5 NAAQS in the San Joaquin Valley and that 
NOX emission sources, therefore, remain subject to control 
requirements under subparts 1 and 4 of part D, title I of the Act. For 
the reasons provided below, the EPA proposes to approve the State's 
demonstration that ammonia, SOX, and VOC emissions do not 
contribute significantly to ambient PM2.5 levels that exceed 
the 2006 PM2.5 NAAQS in the San Joaquin Valley.
    Regarding the State's analytical approach, the EPA finds that the 
State based its analyses on the latest available data and studies 
concerning ambient PM2.5 formation in the San Joaquin Valley 
from precursor emissions. Regarding the required concentration-based 
analysis, the EPA finds that the State assessed the absolute annual 
average contribution of each precursor in ambient PM2.5 
(i.e., in 2015). On the basis of the absolute concentrations being well 
above the EPA's recommended contribution thresholds for both the 24-
hour and annual average NAAQS, the State proceeded with its 
sensitivity-based analysis, which is an acceptable progression of 
analyses under the PM2.5 SIP Requirements Rule.\125\
---------------------------------------------------------------------------

    \125\ For further discussion of the EPA's evaluation of the 
State's concentration-based analysis, see EPA's PM2.5 
Precursor TSD, sections entitled ``Concentration-based analysis'' 
within the EPA's evaluation for each of ammonia, SOX, and 
VOC.
---------------------------------------------------------------------------

    With respect to the sensitivity-based analysis, we find that the 
State performed its analyses in a straightforward application of the 
EPA's recommended approach--i.e., for each modeled year and percent 
precursor emission reduction, the State estimated the ambient 
PM2.5 response using the procedure recommended in the 
PM2.5 Precursor Guidance, and compared the result to the 
recommended contribution threshold. The EPA also finds that the 
performance of the photochemical model was adequate for use in 
estimating the ambient PM2.5 responses, as discussed in 
section J (``Air Quality Model Performance'') of the EPA's ``Technical 
Support Document, EPA Evaluation of Air Quality Modeling, San Joaquin 
Valley PM2.5 Plan for the 2006 PM2.5 NAAQS,'' 
February 2020 (``EPA's Modeling TSD''). The State considered the EPA's 
recommended range of emission reductions (30% to 70%) for the 2013 base 
year, an interim year (2020), and the projected 2024 attainment year 
for the 2006 PM2.5 NAAQS, and quantified the estimated 
response of ambient PM2.5 concentrations to precursor 
emission changes for the first time in a PM2.5 SIP 
submission for the San Joaquin Valley. The EPA finds that such 
quantification and CARB's consideration of additional information 
provide an informed basis on which to make a determination as to 
whether ammonia, SOX, and VOC do or do not contribute 
significantly to ambient PM2.5 levels that exceed the 2006 
PM2.5 NAAQS in the San Joaquin Valley. Therefore, we turn to 
our evaluation of the State's determination for each of these three 
precursor pollutants.
a. Ammonia
    For ammonia, as detailed above, CARB estimated the ambient 
PM2.5 response to both a 30% and a 70% emission reduction. 
We find that it was appropriate for the State to consider additional 
information to interpret those results to determine whether the ammonia 
contribution is significant. We have evaluated CARB's determination 
that the projected 2024 attainment year is more representative of 
conditions in the San Joaquin Valley for sensitivity-based analyses and 
that 30% is a reasonable upper bound for ammonia emission reductions to 
assess the precursor contribution, as discussed below.
    The State provided ample information from scientific studies based 
on ambient measurements to help assess the estimated sensitivity of 
ambient PM2.5 to ammonia reductions. Conclusions based on 
ambient data are particularly relevant because they provide direct 
evidence of the chemical state of the atmosphere, and are not dependent 
on modeled estimates of emissions or

[[Page 17395]]

ambient PM2.5 concentrations. Measurements represent the 
``real world'' result of the pollutants' differing geographic 
distributions, the various meteorological and chemical factors 
influencing their conversion to particulate, and their removal from the 
atmosphere by deposition and other processes. The observed abundance of 
ammonia relative to nitric acid, and the positive amount of chemically 
excess ammonia, both provide strong evidence that ammonia is not the 
limiting pollutant for particulate ammonium nitrate formation. They 
also support the State's conclusion that PM2.5 is likely to 
be insensitive to ammonia emission reductions.
    We note that the model response to precursor reductions may be 
unrealistically large. There is some evidence that ammonia emissions 
may be underestimated based on direct measurements of ammonia emissions 
flux during two measurement campaigns, as discussed in the EPA's 
PM2.5 Precursor TSD. If ammonia emissions were higher in the 
modeling, then ammonia would be more abundant relative to nitrate and 
particulate nitrate formation would be more NOX-limited, and 
less sensitive to ammonia reductions. This would make the model 
response more consistent with the ambient measurement studies, which 
suggest a very low sensitivity to ammonia. The ammonia contribution to 
PM2.5 levels above the standard may therefore be less than 
estimated by the State modeling. The 2024 year modeling incorporates 
lower NOX emissions and so has a larger abundance of ammonia 
relative to nitrate, more similar to the studies' ambient measurements. 
The 2024 response to ammonia reductions may thus be more reliable than 
the 2013 and 2020 responses, and may be more representative of current 
atmospheric conditions despite its use of emission projections for a 
future year.
    The relative sizes of the ammonia and NOX precursor 
emission inventories after accounting for their differing molecular 
weights are a rough indicator of which is the limiting pollutant for 
production of ammonium nitrate, because it forms from a one-to-one 
ratio of molecules derived from each precursor (i.e., one ammonium 
nitrate forms from one ammonium and one nitrate). However, unlike 
measurements and photochemical modeling, a simple emissions ratio does 
not account for the various processes mentioned above; it just assumes 
all the emitted molecules find each other and fully react. The State 
found ammonia to be roughly three times as abundant as NOX 
currently after accounting for their differing molecular weights, and 
even more so in the future. The EPA repeated the exercise to account 
for SOX as well, and found that the ratio of total ammonia 
to that needed to react with both nitrate and sulfate ranged from 2.7 
in 2013 to 5.6 in 2028. These are about the same as the CARB 
NOX-only results, because SOX emissions are very 
small relative to those of NOX and ammonia (e.g., in 2013, 
winter daily emissions were 8.4 tpd SOX, vs. 300.5 tpd for 
NOX and 309.8 tpd for ammonia).\126\ These observations 
support the State's finding that PM2.5 is expected to be 
relatively insensitive to ammonia reductions, though it is not 
definitive.
---------------------------------------------------------------------------

    \126\ 2018 PM2.5 Plan, App. B, Tables B-2, B-3, and 
B-4.
---------------------------------------------------------------------------

    The State also concludes that there are continuing large decreases 
in NOX emissions in the San Joaquin Valley from 2013 to 
2024, including 53% reductions from baseline measures and 10-11% 
reductions from additional new measures, while ammonia emissions are 
projected to remain roughly constant (i.e., decreasing 1-2%).\127\ In 
conjunction with the ambient evidence that ammonia is already 
chemically overabundant relative to NOX in the San Joaquin 
Valley, this shows that in the future the overabundance will become 
even greater, and thus ambient PM2.5 would be even less 
responsive to ammonia reductions. This adds conservatism to the State's 
conclusions about ammonia insensitivity based on the scientific 
studies.
---------------------------------------------------------------------------

    \127\ For further discussion of the SJV PM2.5 Plan's 
control strategy, see section IV.D.4.b of this preamble.
---------------------------------------------------------------------------

    While the base year for an attainment plan for a given 
nonattainment area is generally more representative of current 
conditions, the EPA believes that either a base year or a future year 
may be used for modeling an ambient PM2.5 response to 
precursor emission reductions, provided the state explains how the 
choice of analysis year and associated assumptions are 
appropriate.\128\ The State relied on 2024 model responses mainly on 
the grounds that large NOX emissions reductions will occur 
during 2013-2024, so that the 2024 results will continue to be 
representative, unlike earlier model years. These reductions are the 
result of regulations put in place by past air quality planning 
decisions, and they will occur regardless of decisions about additional 
NOX or ammonia controls in the SJV PM2.5 Plan. In 
assessing the effect of potential ammonia reductions, the EPA believes 
it is reasonable to account for these NOX reductions and the 
effect that ammonia reductions would have in the attainment year and 
after. In addition, as noted above, the greater abundance of ammonia 
relative to NOX in the 2024 year modeling is more consistent 
with recent ambient measurements, and may make the 2024 responses more 
representative of current atmospheric conditions than the other model 
years for assessing sensitivity to ammonia reductions. Therefore, in 
consideration of the scientific studies and emission trends, including 
the projected large amount of NOX emission reductions 
through the attainment period, the EPA agrees that the modeled 2024 
year is acceptable and representative of conditions in the San Joaquin 
Valley.
---------------------------------------------------------------------------

    \128\ PM2.5 Precursor Guidance, 35-36.
---------------------------------------------------------------------------

    In the context of interpreting the full set of modeling results for 
ammonia emissions reductions, the EPA also considered the State's 
conclusion that the absence of available ammonia controls for sources 
in the San Joaquin Valley supports its decision to treat a 30% 
reduction as a reasonable upper bound on the ammonia emission 
reductions to model in estimating the precursor contribution. As the 
State correctly notes, the 30% to 70% range recommended by the EPA is 
based on historical NOX and SOX emission 
reductions, and changes in ammonia emission levels nationally from 2011 
to 2017 ranged from a 9% decrease to a 6% increase.\129\ The State's 
descriptions of both the past research relied upon to develop existing 
rules that apply to ammonia emission sources and ongoing research show 
that it has considered the availability of ammonia controls both in the 
past and in the present context, and that the State has a basis for its 
conclusion that 30% is a reasonable upper bound on achievable 
reductions for ammonia.
---------------------------------------------------------------------------

    \129\ PM2.5 Precursor Guidance, Table 2, page 30.
---------------------------------------------------------------------------

    In sum, we find that the State quantified the sensitivity of 
ambient PM2.5 levels to reductions in ammonia using 
appropriate modeling techniques, which performed well, and that the 
State's choice of 2024 as the reference point for purposes of 
evaluating the sensitivity of ambient PM2.5 levels to 
ammonia emission reductions is well-supported. We also find that the 
State adequately documented its bases for using a 30% reduction in 
ammonia emissions as an upper bound in the modeling to assess ambient 
sensitivity to ammonia emission reductions. Based on all of these 
considerations, the EPA proposes to approve the State's demonstration 
that ammonia emissions do not contribute significantly to ambient 
PM2.5 levels that exceed the 2006 PM2.5 NAAQS in 
the San Joaquin Valley.

[[Page 17396]]

b. SOX
    For SOX, the State found that the ambient 
PM2.5 responses to SOX emission reductions were 
below the EPA's recommended contribution threshold of 1.3 [micro]g/m\3\ 
in the Draft PM2.5 Precursor Guidance (and below the EPA's 
recommended threshold of 1.5 [micro]g/m\3\ in the (final) 
PM2.5 Precursor Guidance) and, indeed, that for most sites 
there would be an increase in ambient PM2.5 levels in 
response to such reductions (i.e., a disbenefit). The EPA has evaluated 
the State's determination as to this disbenefit and the State's 
resulting conclusion as to the precursor's significance.
    Because the results of the sensitivity analysis were all below the 
EPA's recommended 24-hour contribution thresholds at both the 30% and 
70% emission reductions, and in both the 2013 base year and 2024 
attainment year, it is not necessary to distinguish between the timing 
and scale of emission reductions with respect to the response of 
ambient PM2.5 levels, as in the ammonia evaluation where the 
results diverged according to scale and timing of modeled emission 
reductions. The EPA's PM2.5 Precursor TSD contains 
additional detail on the EPA's evaluation of SOX as a 
PM2.5 precursor, including the unexpected disbenefit of 
reducing SOX emissions. Accordingly, we find that the 
State's decision to rely on the 2013 sensitivity modeling results for a 
30% SOX reduction is acceptable.
    Therefore, on the basis of the modeled ambient PM2.5 
response to both a 30% and 70% reduction in SOX emissions in 
2013, and the facts and circumstances of the area, the EPA proposes to 
approve the State's demonstration that SOX emissions do not 
contribute significantly to ambient PM2.5 levels that exceed 
the 2006 PM2.5 NAAQS in the San Joaquin Valley.
c. VOC
    For VOC, the State found that the ambient PM2.5 response 
to VOC emission reductions were generally below the EPA's recommended 
contribution threshold of 1.3 [micro]g/m\3\ in the Draft 
PM2.5 Precursor Guidance (and below the EPA's recommended 
threshold of 1.5 [micro]g/m\3\ in the final PM2.5 Precursor 
Guidance), and often predicted an increase in ambient PM2.5 
levels in response to such reductions (i.e., a disbenefit), except for 
a 70% emission reduction for the 2013 base year, where the State 
predicted the ambient PM2.5 response to be above both 
recommended thresholds at a majority of sites. The EPA has evaluated 
and agrees with the State's determination that the projected 2024 
attainment year is more representative of conditions in the San Joaquin 
Valley for sensitivity-based analyses and that VOC reductions in 2024 
would mostly result in a disbenefit to ambient PM2.5 levels, 
as well as the State's resulting conclusion as to whether VOC's 
contribution is significant.
    Regarding emission trends, the EPA agrees that the 9% VOC emissions 
decrease from 2013 to 2024 favors reliance on the 2024 modeling 
results. Furthermore, there is a large decrease in NOX 
emissions over this period, as discussed in the EPA's evaluation of 
ammonia in section IV.B.3.a of this preamble, which affects the 
atmospheric chemistry with respect to ambient PM2.5 
formation from VOC emissions. The 9% VOC emission reductions and the 
vast majority of NOX emissions will result from baseline 
measures that are projected to occur, even absent any further action by 
the State. We therefore find it reasonable to rely on future year 2024 
modeled responses to VOC reductions. The EPA also finds that the State 
provided a reasonable explanation for the VOC reduction disbenefit and 
evidence that it occurs in the San Joaquin Valley.
    For all of these reasons, we propose to approve the State's 
demonstration that VOC emissions do not contribute significantly to 
ambient PM2.5 levels that exceed the 2006 PM2.5 
NAAQS in the San Joaquin Valley.

C. Best Available Control Measures and Most Stringent Measures

1. Statutory and Regulatory Requirements
    Section 189(b)(1)(B) of the Act requires for any serious 
PM2.5 nonattainment area that the state submit provisions to 
assure that the best available control measures (BACM) for the control 
of PM2.5 and PM2.5 precursors shall be 
implemented no later than four years after the date the area is 
reclassified as a serious area. The EPA has defined BACM in the 
PM2.5 SIP Requirements Rule to mean ``any technologically 
and economically feasible control measure that can be implemented in 
whole or in part within 4 years after the date of reclassification of a 
Moderate PM2.5 nonattainment area to Serious and that 
generally can achieve greater permanent and enforceable emissions 
reductions in direct PM2.5 emissions and/or emissions of 
PM2.5 plan precursors from sources in the area than can be 
achieved through the implementation of RACM on the same source(s). BACM 
includes best available control technology (BACT).'' \130\
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    \130\ 40 CFR 51.1000 (definitions). In longstanding guidance, 
the EPA has similarly defined BACM to mean, ``among other things, 
the maximum degree of emissions reduction achievable for a source or 
source category, which is determined on a case-by-case basis 
considering energy, environmental, and economic impacts.'' General 
Preamble Addendum, 42010, 42013.
---------------------------------------------------------------------------

    The EPA generally considers BACM a control level that goes beyond 
existing RACM-level controls, for example by expanding the use of RACM 
controls or by requiring preventative measures instead of 
remediation.\131\ Indeed, as implementation of BACM and BACT is 
required when a Moderate nonattainment area is reclassified as Serious 
due to its inability to attain the NAAQS through implementation of 
``reasonable'' measures, it is logical that ``best'' control measures 
should represent a more stringent and potentially more costly level of 
control.\132\ If RACM and RACT level controls of emissions have been 
insufficient to reach attainment, the CAA contemplates the 
implementation of more stringent controls, controls on more sources, or 
other adjustments to the control strategy necessary to attain the NAAQS 
in the area.
---------------------------------------------------------------------------

    \131\ 81 FR 58010, 58081 and General Preamble Addendum, 42011, 
42013.
    \132\ Id. and General Preamble Addendum, 42009-42010.
---------------------------------------------------------------------------

    Consistent with longstanding guidance provided in the General 
Preamble Addendum, the preamble to the PM2.5 SIP 
Requirements Rule discusses the following steps for determining BACM 
and BACT:
    (1) Develop a comprehensive emission inventory of the sources of 
PM2.5 and PM2.5 precursors;
    (2) Identify potential control measures;
    (3) Determine whether an available control measure or technology is 
technologically feasible;
    (4) Determine whether an available control measure or technology is 
economically feasible; and
    (5) Determine the earliest date by which a control measure or 
technology can be implemented in whole or in part.\133\
---------------------------------------------------------------------------

    \133\ 81 FR 58010, 58083-58085.
---------------------------------------------------------------------------

    The EPA allows consideration of factors such as physical plant 
layout, energy requirements, needed infrastructure, and workforce type 
and habits when considering technological feasibility. For purposes of 
evaluating economic feasibility, the EPA allows consideration of 
factors such as the capital costs, operating and maintenance costs, and 
cost effectiveness (i.e., cost per ton of

[[Page 17397]]

pollutant reduced by a measure or technology) associated with the 
measure or control.\134\
---------------------------------------------------------------------------

    \134\ 40 CFR 51.1010(a)(3) and 81 FR 58010, 58041-58042.
---------------------------------------------------------------------------

    Once these analyses are complete, the state must use this 
information to develop enforceable control measures and submit them to 
the EPA for evaluation as SIP provisions to meet the basic requirements 
of CAA section 110 and any other applicable substantive provisions of 
the Act. The EPA is using these steps as guidelines in the evaluation 
of the BACM and BACT measures and related analyses in the SJV 
PM2.5 Plan.
    Because the EPA reclassified the San Joaquin Valley as Serious 
nonattainment for the 2006 PM2.5 NAAQS effective February 
19, 2016,\135\ the date four years after reclassification is February 
19, 2020. In this case, however, the Serious area attainment date for 
the 2006 PM2.5 NAAQS in the San Joaquin Valley under section 
188(c) is no later than December 31, 2019, and to qualify for an 
extension of this date under section 188(e), the state must, among 
other things, demonstrate that implementation of BACM and BACT for 
relevant source categories will not bring the area into attainment by 
this date. Given these circumstances, the EPA is evaluating the Plan's 
control strategy for implementation of BACM and BACT as expeditiously 
as practicable and no later than December 31, 2019.\136\
---------------------------------------------------------------------------

    \135\ 81 FR 2993.
    \136\ CAA section 189(b)(1)(B) establishes an outermost deadline 
(``no later than four years after the date the area is 
reclassified'') and does not preclude an earlier implementation 
deadline for BACM where necessary to satisfy the attainment 
requirements of the Act.
---------------------------------------------------------------------------

    In addition, before the EPA may extend the attainment date for a 
Serious nonattainment area under CAA section 188(e), the state must, 
among other things, demonstrate to the satisfaction of the 
Administrator that the plan for the area includes the most stringent 
measures (MSM) that are included in the implementation plan of any 
state or are achieved in practice in any state, and can feasibly be 
implemented in the area. The state must implement MSM as expeditiously 
as practicable and no later than the beginning of the year containing 
the attainment date identified by the state in its extension request, 
i.e., in this case, by January 1, 2024, because the State is seeking an 
extension of the attainment date to December 31, 2024, under section 
188(e).\137\ Section III.B of this preamble contains a more detailed 
discussion of the MSM requirement in CAA section 188(e).
---------------------------------------------------------------------------

    \137\ 40 CFR 51.1011(b)(5) (requiring implementation of all 
control measures needed for attainment as expeditiously as 
practicable and no later than the beginning of the year containing 
the applicable attainment date).
---------------------------------------------------------------------------

2. Summary of State's Submission
    As discussed in section IV.A of this proposed rule, Appendix B of 
the 2018 PM2.5 Plan contains the planning inventories for 
direct PM2.5 and all PM2.5 precursors 
(NOX, SOX, VOC, and ammonia) for the San Joaquin 
Valley nonattainment area together with documentation to support these 
inventories. Each inventory includes emissions from stationary, area, 
on-road, and non-road emission sources, and the State specifically 
identifies the condensable component of direct PM2.5 for 
relevant stationary and area source categories. As discussed in section 
IV.B of this preamble, the State's analysis indicates that the Plan 
should control emissions of PM2.5 and NOX in 
order to reach attainment. Accordingly, the Plan evaluates potential 
controls for those pollutants in the analysis of what is necessary to 
meet the BACM (including BACT) and MSM requirements.
    For stationary and area sources, the District identifies the 
sources of direct PM2.5 and NOX in the San 
Joaquin Valley that are subject to District emission control measures 
and provides its evaluation of these regulations for compliance with 
BACM and MSM requirements in Appendix C of the 2018 PM2.5 
Plan. As part of its process for identifying candidate BACM and MSM and 
considering the technical and economic feasibility of additional 
control measures, the District reviewed the EPA's guidance documents on 
BACM, additional guidance documents on control measures for direct 
PM2.5 and NOX emission sources, and control 
measures implemented in other ozone and PM2.5 nonattainment 
areas in California and other states.\138\
---------------------------------------------------------------------------

    \138\ 2018 PM2.5 Plan, Chapter 4, section 4.3.1.
---------------------------------------------------------------------------

    For mobile sources, CARB identifies the sources of direct 
PM2.5 and NOX in the San Joaquin Valley that are 
subject to the State's emission control measures and provides its 
evaluation of these regulations for compliance with BACM and MSM 
requirements in Appendix D of the 2018 PM2.5 Plan. Appendix 
D describes CARB's process for determining BACM and MSM, including 
identification of the sources of direct PM2.5 and 
NOX in the San Joaquin Valley, identification of potential 
control measures for such sources, assessment of the stringency and 
feasibility of the potential control measures, and adoption and 
implementation of feasible control measures.\139\ CARB further 
discusses its current mobile source control program and additional 
mobile source measures in the Valley State SIP Strategy. Appendix D of 
the 2018 PM2.5 Plan also describes the current efforts of 
the eight local jurisdiction metropolitan planning organizations (MPOs) 
to implement cost-effective transportation control measures (TCMs) in 
the San Joaquin Valley.\140\
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    \139\ Id. at App. D, Ch. II.
    \140\ Id. at App. D, D-127 and D-128.
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3. EPA's Evaluation and Proposed Action
    As discussed in sections III.B and IV.D of this preamble, the EPA 
has established a process for evaluating potential BACM (including 
BACT) in serious area plans and a similar process for evaluating MSM. 
Because of the substantial overlap in the source categories and 
controls evaluated for BACM and those evaluated for MSM, we present our 
evaluation of the SJV PM2.5 Plan's provisions for including 
MSM alongside our evaluation of the Plan's provisions for implementing 
BACM and BACT for each identified source category.
    The first step in determining BACM and MSM is to develop a 
comprehensive emissions inventory of the sources of direct 
PM2.5 and relevant PM2.5 precursors that can be 
used with modeling to determine the effects of these sources on ambient 
PM2.5 levels. Based on our review of the emission 
inventories provided in Appendix B of the 2018 PM2.5 Plan 
and the State's and District's identification of the sources subject to 
control in Appendix C and Appendix D, the EPA is proposing to find that 
the Plan appropriately identifies all sources of direct 
PM2.5 and NOX that are subject to evaluation for 
potential control consistent with the requirements of subpart 4 of part 
D, title I of the Act.
    The remaining steps are to identify potential control measures for 
each source category, determine whether available control measures or 
technologies are technologically and economically feasible for 
implementation in the area, and determine the earliest date by which 
those control measures or technologies found to be feasible can be 
implemented, in whole or in part.\141\
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    \141\ 81 FR 58010, 58083-58085. The EPA's recommended steps for 
a BACM demonstration are substantively similar to the required steps 
for an MSM demonstration in 40 CFR 51.1010(b).
---------------------------------------------------------------------------

    We discuss below key components of the BACM and MSM evaluations 
provided by the District, CARB, and the

[[Page 17398]]

local jurisdiction MPOs in the SJV PM2.5 Plan in accordance 
with these steps. We provide a more detailed evaluation of many of the 
District's control measures for stationary and area sources in the 
EPA's ``Technical Support Document, EPA Evaluation of BACM/MSM, San 
Joaquin Valley PM2.5 Plan for the 2006 PM2.5 
NAAQS,'' February 2020 (``EPA's BACM/MSM TSD''), together with 
recommendations for possible future improvements to these rules.
a. District Measures for Stationary and Area Sources
Open Burning
    SJVUAPCD Rule 4103 (``Open Burning''), as amended April 15, 2010, 
is designed to minimize impacts of smoke and other air pollutants from 
open burning of agricultural waste and other materials.\142\ The rule 
restricts the type of materials that may be burned and establishes 
other conditions and procedures for open burning in conjunction with 
the District's Smoke Management Program.\143\ The EPA approved Rule 
4103 into the California SIP on January 4, 2012.\144\
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    \142\ SJVUAPCD Rule 4103, as amended April 15, 2010.
    \143\ Id.
    \144\ 77 FR 214 (January 4, 2012).
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    The District compared Rule 4103 to several other open burning rules 
implemented in other parts of California and found that no other rules 
are more stringent, as a whole, than Rule 4103. According to the 
information provided, although the South Coast Air Quality Management 
District (SCAQMD) implements a rule that restricts burning on 
residential wood combustion (RWC) curtailment days (Rule 444) and 
District Rule 4103 does not contain the same restriction, in practice 
the District generally limits burning on RWC curtailment days through 
implementation of its Smoke Management Program, which specifically 
allocates allowable burn acreage for 97 geographic zones based on local 
meteorology. We note that a restriction on burning on RWC curtailment 
days by itself may not consistently reduce wintertime PM2.5 
emission levels as it could shift more waste burning activity to days 
with more favorable meteorology. On balance we find that Rule 4103's 
general prohibitions on the burning of specific agricultural crops and 
burn permitting program are more effective means for reducing 
PM2.5 emissions than targeted restrictions on RWC 
curtailment days.
    Sections 41855.5 and 41855.6 of the California Health and Safety 
Code require the District to prohibit open burning of specific crop 
categories unless the District determines either that there is no 
economically feasible alternative means of eliminating the waste or 
that there is no long-term federal or state funding commitment for the 
continued operation of biomass facilities in the San Joaquin Valley or 
for the development of alternatives to burning.\145\ The District has 
considered the technical and economic feasibility of alternatives to 
burning several times in the last several years and concluded that such 
alternatives are not feasible for selected crop categories at this 
time.\146\
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    \145\ California Health & Safety Code, sections 41855.5 and 
41855.6.
    \146\ 2018 PM2.5 Plan, App. C, C-18 and C-23 to C-29.
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Boilers, Steam Generators, and Process Heaters Greater Than 5.0 Million 
British Thermal Units per Hour (MMBtu/hr)
    SJVUAPCD Rule 4306 (``Boilers, Steam Generators, and Process 
Heaters--Phase 3''), as amended October 16, 2008, establishes 
NOX emission limits ranging from 5 to 30 parts per million 
(ppm) and related operational requirements for gaseous fuel- or liquid 
fuel-fired boilers, steam generators, and process heaters with total 
rated heat input greater than 5 MMBtu/hr.\147\ The EPA approved Rule 
4306 into the California SIP on January 13, 2010.\148\ SJVUAPCD Rule 
4320 (``Advanced Emission Reduction Options for Boilers, Steam 
Generators, and Process Heaters Greater Than 5.0 MMBtu/hr''), as 
adopted October 16, 2008, establishes more stringent NOX 
emission limits (5 to 12 ppm) and related operational requirements for 
these units but allows sources to pay an emission fee in lieu of 
compliance with the NOX emission limits.\149\ The EPA 
approved Rule 4320 into the California SIP on March 25, 2011, but 
determined that this rule, as approved, may not be credited for 
attainment planning purposes because the fee provision renders the 
NOX emission limits unenforceable.\150\
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    \147\ SJVUAPCD Rule 4306, as amended October 16, 2008.
    \148\ 75 FR 1715 (January 13, 2010).
    \149\ SJVUAPCD Rule 4320, as adopted October 16, 2008.
    \150\ 76 FR 16696 (March 25, 2011).
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    The District compared both Rule 4306 and Rule 4320 to several other 
analogous rules implemented in other parts of California, including the 
Sacramento Metro area, the South Coast, and the Bay Area.\151\ 
According to the information provided in Appendix C of the 2018 
PM2.5 Plan, the NOX emission limits in Rule 4306 
are generally within the same range as, and in some cases are more 
stringent than, those contained in analogous rules implemented by these 
other California agencies, except that the SCAQMD implements a rule 
containing NOX emission limits that are potentially more 
stringent for units of certain sizes (SCAQMD Rule 1146, as amended 
November 1, 2013).\152\
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    \151\ 2018 PM2.5 Plan, App. C, C-71 to C-79.
    \152\ Id. and 79 FR 57442 (September 25, 2014) (final action 
approving Rule 1146 into California SIP). The SCAQMD amended Rule 
1146 on December 8, 2018 and CARB submitted the amended rule to the 
EPA on February 6, 2020. The amended rule is available at http://www.aqmd.gov/docs/default-source/rule-book/reg-xi/rule-1146.pdf?sfvrsn=4.
---------------------------------------------------------------------------

    SCAQMD Rule 1146 establishes a 5 ppm NOX emission limit 
for larger units (i.e., those with heat rate inputs above 75 MMBtu/hr), 
whereas Rule 4320 establishes a 7 ppm limit and Rule 4306 establishes a 
9 ppm limit for such units.\153\ SCAQMD Regulation XX (``Regional Clean 
Air Incentives Market'' or ``RECLAIM'') also applies to units within 
the same range of sizes as Rule 4320 but allows sources to comply with 
emission caps by purchasing RECLAIM Trading Credits.\154\ Because 
SCAQMD Rule 1146 allows individual units with rated heat inputs above 
75 MMBtu/hr to comply with RECLAIM in lieu of compliance with the 5 ppm 
emission limit in the rule,\155\ the SIP-approved NOX 
emission limit for these units in the South Coast is either the 
applicable limit in SCAQMD Rule 1146 or the applicable provision of the 
RECLAIM program, which may allow for emission levels higher than 5 ppm 
at individual units.\156\ We do not have information

[[Page 17399]]

about the rated heat input of the units subject to RECLAIM in the South 
Coast and, therefore, have no information confirming that any unit with 
a rated heat input above 75 MMBtu/hr has achieved the 5 ppm 
NOX emission limit in Rule 1146.
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    \153\ Compare SCAQMD Rule 1146 (as amended November 1, 2013) at 
section (c)(1)(F) to SJVUAPCD Rule 4320 at Table 1, category B.a and 
SJVUAPCD Rule 4306 at Table 1, category B; see also 2018 
PM2.5 Plan, App. C, C-73. The SCAQMD's December 8, 2018 
amendments to Rule 1146 did not alter the provisions of section 
(c)(1)(F).
    \154\ RECLAIM is a market incentive program designed to allow 
facilities flexibility in achieving emission reduction requirements 
for NOX and SOX through, among other things, 
add-on controls, equipment modifications, reformulated products, 
operational changes, shutdowns, and the purchase of excess emission 
reductions. SCAQMD Rule 2000, section (a). The SCAQMD is currently 
transitioning the RECLAIM program to a command-and-control 
regulatory structure requiring ``best available retrofit control 
technology'' as soon as practicable. See, e.g., SCAQMD, Draft Staff 
Report, ``Proposed Amended Rule 1110.2--Emissions from Gaseous- and 
Liquid-Fueled Engines, Proposed Amended Rule 1100--Implementation 
Schedule for NOX Facilities,'' September 2019, Chapter 1.
    \155\ SCAQMD Rule 1146, ``Emissions of NOX from 
Industrial, Institutional, and Commercial Boilers and Steam 
Generators, and Process Heaters'' (amended November 1, 2013), Table 
1146-1, section (a)(4) and SCAQMD Rule 2001, ``Applicability'' 
(amended May 6, 2005), section (j) and Table 1.
    \156\ The EPA's most recent action approving revisions to the 
RECLAIM program into the California SIP published on September 14, 
2017. 82 FR 43176.
---------------------------------------------------------------------------

    The District also considered the technical and economic feasibility 
of alternative NOX and PM2.5 control techniques 
for this source category, such as low temperature oxidation and 
EMX system for NOX control, and alternative 
fuels, electrostatic precipitators (ESP) and wet scrubbers for direct 
PM2.5 control.\157\ Based on its consideration of the 
technical constraints and costs associated with each of these control 
options, as explained in Appendix C of the 2018 PM2.5 Plan, 
the District concluded that these additional controls are not feasible 
for implementation in the San Joaquin Valley at this time.\158\
---------------------------------------------------------------------------

    \157\ 2018 PM2.5 Plan, App. C, C-88 to C-92.
    \158\ Id.
---------------------------------------------------------------------------

    Although the NOX emission limits in Rule 4320 do not 
satisfy the Act's enforceability requirements because of the option to 
pay an emission fee, we note that the requirement to pay the emission 
fee itself is an enforceable requirement and that the fee provision 
appears to function effectively as a pollution deterrent.\159\
---------------------------------------------------------------------------

    \159\ EPA's BACM/MSM TSD at section 3.b.5.
---------------------------------------------------------------------------

Flares
    SJVUAPCD Rule 4311 (``Flares''), as amended June 18, 2009, 
establishes specific operational and administrative requirements to 
limit emissions of NOX, SOX, and VOCs from the 
operation of flares.\160\ Under Rule 4311, for each refinery flare and 
other flare with a capacity above 5 MMBtu/hr, the operator must submit 
a flare minimization plan (FMP) to the District describing relevant 
equipment and preventative measures and demonstrating that the operator 
appropriately minimized flaring activity.\161\ The EPA approved Rule 
4311 into the California SIP on November 3, 2011.\162\
---------------------------------------------------------------------------

    \160\ SJVUAPCD Rule 4311, as amended June 18, 2009.
    \161\ Id.
    \162\ 76 FR 68106 (November 3, 2011).
---------------------------------------------------------------------------

    The District compared Rule 4311 with several other analogous rules 
implemented in other parts of California, including the South Coast, 
Bay Area, and Santa Barbara, all of which require regulated sources to 
submit FMPs to the local air districts.\163\ The District also compared 
Rule 4311 with North Dakota's Century Code 38-08-06.4, which requires, 
among other things, that after one year of uncontrolled operations each 
oil well be equipped with a control system that captures at least 75% 
of the gas (i.e., allowing up to 25% of the gas to be flared).\164\ 
According to the information provided, the average volume of gas flared 
at facilities in the San Joaquin Valley between 2009 and 2013 was 3.8%, 
well below both the amount of flaring allowed under the North Dakota 
rule and the amount allowed in the Santa Barbara Air Pollution Control 
District's Rule 359, which requires that each FMP list a targeted 
maximum monthly flared gas volume of 5% of the average monthly gas 
handled/produced/treated, with limited exceptions.\165\ As described in 
Appendix C of the 2018 PM2.5 Plan, the District concluded 
that, because of wide variation in flaring operations in the San 
Joaquin Valley, requirements to submit detailed FMPs, as in Rule 4311, 
are the most effective means of reducing NOX emissions from 
flaring and that additional control techniques are not technologically 
and economically feasible for implementation in the San Joaquin Valley 
at this time.\166\
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    \163\ 2018 PM2.5 Plan, App. C, C-150 to C-156.
    \164\ Id. at C-155 and North Dakota Century Code 38-08-06.4, 
section 2.d (as in effect February 13, 2015), available at https://www.legis.nd.gov/cencode/t38c08.pdf?20150213153521.
    \165\ 2018 PM2.5 Plan, C-154 and C-155.
    \166\ Id. at C-147 to C-148 and C-156 to C-161.
---------------------------------------------------------------------------

    Consistent with a commitment in a prior PM2.5 attainment 
plan to evaluate the technological and economic feasibility of 
additional flare minimization practices, the District recently 
conducted a comprehensive evaluation of the most effective flare 
minimization practices included in approved FMPs and additional 
NOX control information and published two reports containing 
its findings and recommendations.\167\ As part of its final report in 
2016, the District identified flare minimization practices in use at 
certain facilities that could be employed at other facilities to reduce 
flaring and stated its intent to propose potential rule amendments to 
require use of these practices where technologically and economically 
feasible.\168\ Additionally, the District found that ultra-low 
NOX control technologies have recently become available and 
stated its intent to thoroughly evaluate this control option and to 
then propose potential rule amendments to require use of these controls 
where technologically and economically feasible.\169\ In the 2018 
PM2.5 Plan, the District provided a summary economic 
analysis indicating that the annualized cost-effectiveness of ultra-low 
NOX control technology would range from $23,000 to $1 
million per ton of NOX reduced.\170\ Finally, the District 
considered a number of alternatives to flaring, preventative 
maintenance measures, procedures to reduce flaring during maintenance 
and shutdowns, and procedures to prevent or mitigate effects of power 
outages that would further reduce NOX emissions from this 
source category.\171\
---------------------------------------------------------------------------

    \167\ SJVUAPCD, ``Rule 4311 (Flares) Further Study, 2014,'' 
September 16, 2014 and SJVUAPCD, ``Further Study, Rule 4311 Flare 
Minimization Plans, 2015,'' March 31, 2016.
    \168\ SJVUAPCD, ``Further Study, Rule 4311 Flare Minimization 
Plans, 2015,'' March 31, 2016, 16-17.
    \169\ Id.
    \170\ 2018 PM2.5 Plan, C-156 and C-157.
    \171\ Id. at C-157 to C-161.
---------------------------------------------------------------------------

Solid Fuel-Fired Boilers
    SJVUAPCD Rule 4352 (``Solid Fuel-Fired Boilers, Steam Generators, 
and Process Heaters''), as amended December 15, 2011, establishes 
NOX emission limits and related operational requirements for 
boilers, steam generators, and process heaters that burn municipal 
solid waste (MSW), biomass, and other solid fuels.\172\ Specifically, 
the rule establishes NOX emission limits of 165 parts per 
million volume (ppmv) for units burning MSW, 90 ppmv for units burning 
biomass, and 65 ppmv for units burning other solid fuels.\173\ The EPA 
approved the District's 2011 amendments to this rule into the 
California SIP on November 6, 2012.\174\
---------------------------------------------------------------------------

    \172\ SJVUAPCD Rule 4352, as amended December 15, 2011.
    \173\ Id.
    \174\ 77 FR 66548 (November 6, 2012).
---------------------------------------------------------------------------

    As described in Appendix C of the 2018 PM2.5 Plan, the 
NOX emission limits in Rule 4352 have been lowered 
significantly over time and are at least as stringent as analogous 
requirements implemented in other parts of California. The District 
compared the provisions of Rule 4352 to potentially more stringent 
rules implemented in the South Coast Air Quality Management District 
(SCAQMD) (Rule 1146), Bay Area Air Quality Management District (BAAQMD) 
(Regulation 9 Rule 7) and Sacramento Metropolitan Air Quality 
Management District (SMAQMD) (Rule 411) and found that the lower 
NOX emission limits in these rules are not comparable to the 
provisions of Rule 4352. According to the District, all of remaining 
solid fuel-fired boilers operating in the San Joaquin Valley are used 
by electric utilities to generate electricity, a category that is 
specifically exempted from the requirements of SCAQMD Rule 1146, BAAQMD 
Regulation 9 Rule 7, and SMAQMD

[[Page 17400]]

Rule 411.\175\ The District also compared Rule 4352 to analogous rules 
implemented by three other California air districts that apply to 
active biomass-fueled units, the Yolo-Solano Air Quality Management 
District (YSAQMD), El Dorado County Air Quality Management District 
(EDAQMD), and Placer County Air Pollution Control District (PCAPCD), 
and found that the NOX emission limits for biomass-fueled 
units in these regulations are all within the same range as the limits 
in SJVUAPCD Rule 4352.\176\
---------------------------------------------------------------------------

    \175\ 2018 PM2.5 Plan, App. C, C-165 to C-167.
    \176\ Id. at C-168 to C-169.
---------------------------------------------------------------------------

    The District also considered the technological and economic 
feasibility of alternative control techniques for this source category, 
such as selective catalytic reduction (SCR) and ``Covanta LN'' 
technology for NOX control and catalytic baghouse filter 
bags (``Gore De-NOX systems'') for direct PM2.5 
control.\177\ Based primarily on its consideration of the costs 
associated with retrofitting these controls onto existing MSW-fired or 
biomass-fired units, the District concluded in the 2018 
PM2.5 Plan that none of these control options is 
economically feasible for sources in the San Joaquin Valley at this 
time.\178\ The District noted, however, that in May 2018 it issued a 
construction permit requiring installation of Covanta LN technology to 
limit NOX emissions from certain MSW-fired units and that it 
would continue to monitor the implementation of this control technology 
to determine whether it is feasible for implementation on a continuous 
basis.\179\
---------------------------------------------------------------------------

    \177\ Id. at C-170 to C-179.
    \178\ Id.
    \179\ Id. at C-179. The permitted source had not yet begun 
construction at the time the District adopted the 2018 
PM2.5 Plan.
---------------------------------------------------------------------------

    We have reviewed the relevant provisions of BAAQMD Regulation 9-7, 
SCAQMD Rule 1146 and SMAQMD Rule 411 and agree with the District's 
conclusion that these SIP-approved regulations exempt from their 
NOX emission limits boilers used at electric utilities to 
generate electricity.\180\
---------------------------------------------------------------------------

    \180\ BAAQMD Regulation 9-7, section 110.4, SCAQMD Rule 1146, 
section 110, and SMAQMD Rule 41, section (f)(1).
---------------------------------------------------------------------------

Glass Melting Furnaces
    SJVUAPCD Rule 4354 (``Glass Melting Furnaces''), as amended May 19, 
2011, establishes NOX, VOC, SOX, and 
PM10 emission limits and related operational requirements 
for glass melting furnaces.\181\ Specifically, the rule establishes 
NOX emission limits of 1.5 to 3.7 lb. NOX/ton 
glass, depending on glass product and averaging time, and 
SOX emission limits of 0.9 to 1.7 lb. SOX/ton 
glass.\182\ The EPA approved the District's 2011 amendments to Rule 
4354 into the California SIP on January 31, 2013.\183\
---------------------------------------------------------------------------

    \181\ SJVUAPCD Rule 4354, as amended May 19, 2011.
    \182\ Id. at 5, 7.
    \183\ 78 FR 6740 (January 31, 2013).
---------------------------------------------------------------------------

    According to information provided in Appendix C of the 2018 
PM2.5 Plan, the NOX emission limits in Rule 4354 
require implementation of oxy-fuel firing or SCR systems, which are the 
best available NOX control techniques for this source 
category and are at least as stringent as analogous requirements 
implemented in the South Coast and Bay Area.\184\ We are not aware of 
prohibitory rules for glass melting furnaces in other areas that are 
more stringent than Rule 4354.
---------------------------------------------------------------------------

    \184\ 2018 PM2.5 Plan, App. C, C-189 to C-194.
---------------------------------------------------------------------------

    As part of our review of a previous PM2.5 attainment 
plan submitted for the San Joaquin Valley, we also considered whether 
NOX emission levels lower than the limits in Rule 4354 may 
be feasible for container glass manufacturing facilities. Specifically, 
under the SCAQMD's RECLAIM Program, the SCAQMD determined in 2000 that 
a NOX limit of 1.2 lbs NOX/ton of glass pulled 
represented Best Available Retrofit Control Technology (BARCT),\185\ 
and in 2015 the SCAQMD determined that a lower NOX limit of 
0.24 lbs NOX/ton of glass pulled represents BARCT for this 
source category based on use of SCR or the ``Ultra Cat ceramic filter 
system,'' which has been installed or is under construction at a number 
of glass manufacturing locations worldwide.\186\ The EPA obtained 
information from the SCAQMD indicating that the Owens-Brockway 
Container Glass facility in the South Coast (now operated by Owens-
Illinois Glass Company) operated at 90% production capacity in February 
2015 and consistently emitted below 0.72 lbs NOX/ton of 
glass pulled during that month, using oxyfuel firing to control 
NOX emissions.\187\
---------------------------------------------------------------------------

    \185\ BARCT is defined as ``an emission limitation that is based 
on the maximum degree of reduction achievable taking into account 
environmental, energy, and economic impacts by each class or 
category of source.'' California Health & Safety Code Section 40406.
    \186\ SCAQMD, Draft Final Staff Report, ``Proposed Amendments to 
Regulation XX, Regional Clean Air Incentives Market (RECLAIM), 
NOX RECLAIM,'' December 4, 2015, 170-171. The RECLAIM 
program requires that container glass melting facilities achieve 
NOX reductions consistent with the 2015 BARCT 
determination (0.24 lbs NOX/ton of glass pulled) by 2022. 
SCAQMD Rule 2002 (as amended October 5, 2018), subparagraph 
(f)(1)(K) and Table 6 (``RECLAIM NOX 2022 Ending Emission 
Factors'').
    \187\ 81 FR 69396, 69399 (October 6, 2016) (citing email dated 
April 13, 2016, from Kevin Orellana, SCAQMD to Idalia Perez, EPA 
Region IX).
---------------------------------------------------------------------------

    Given this information, the EPA requested additional information 
from the District about the technological and economic feasibility of 
additional NOX control techniques for container glass 
manufacturing facilities, and on January 28, 2020, the District 
submitted a document entitled ``Further Information for EPA Regarding 
the MSM Analysis for District Rule 4354 (Glass Melting Furnaces)'' 
(referred to herein as the ``Rule 4354 Additional Analysis'').\188\ The 
information provided by the District indicates that, because the costs 
due to lost production can be significant if a glass melting furnace is 
taken off-line during the middle of its campaign, retrofits to install 
additional combustion controls are generally performed only when a 
furnace is shut down for rebricking, which occurs once every 10 to 15 
years.\189\ Because of wide variations in the costs and technical 
difficulties associated with installation of NOX controls 
depending on the physical layout of each furnace and the time of its 
last re-bricking, the District concluded that generic economic 
feasibility analyses are not possible and that extensive facility-
specific evaluations would be necessary to determine whether additional 
control technologies are feasible for implementation at the three 
container glass melting facilities currently operating in the San 
Joaquin Valley.\190\
---------------------------------------------------------------------------

    \188\ Email dated January 28, 2020, from John Klassen, SJVUAPCD 
to Doris Lo, EPA Region IX, Subject: ``RE: Follow up questions on 
glass melting and IC engines for MSM analysis,'' attaching ``Further 
Information for EPA Regarding the MSM Analysis for District Rule 
4354 (Glass Melting Furnaces)'' (``Rule 4354 Additional Analysis'').
    \189\ Rule 4354 Additional Analysis, 5-7.
    \190\ Id.
---------------------------------------------------------------------------

    Further, the District also stated in Appendix C of the 2018 
PM2.5 Plan that the Owens-Brockway (now Owens-Illinois) 
facility in the South Coast has experienced wide-ranging spikes in the 
NOX emissions from its glass furnaces while operating its 
new control systems and that it is not known at this time whether the 
facility will be able to consistently achieve emission rates as low as 
0.20 lbs of NOX/ton of glass produced as shown by the 
facility's preliminary source test data from 2018.\191\
---------------------------------------------------------------------------

    \191\ 2018 PM2.5 Plan, App. C, C-195.
---------------------------------------------------------------------------

    We agree with the District's conclusion that the feasibility of 
retrofits to install additional NOX controls at the existing 
glass melting facilities in the San Joaquin Valley is

[[Page 17401]]

highly dependent on timing and site-specific factors, as the real costs 
of installing post-combustion controls or oxy-fuel firing retrofits and 
the lost revenue resulting from early furnace shutdowns may vary 
significantly from facility to facility.
Stationary Internal Combustion Engines
    SJVUAPCD Rule 4702 (``Internal Combustion Engines''), as amended 
November 14, 2013, establishes NOX, CO, VOC, and 
SOX emission limits and related operational requirements for 
internal combustion (IC) engines.\192\ The rule contains separate 
emission limits for spark-ignited IC engines used in agricultural 
operations (SI AO engines), spark-ignited IC engines used in non-
agricultural operations (SI non-AO engines), and compression-ignited IC 
engines.\193\ The EPA approved the District's 2013 amendments to this 
rule into the California SIP on April 25, 2016.\194\
---------------------------------------------------------------------------

    \192\ SJVUAPCD Rule 4702, as amended November 14, 2013.
    \193\ Id.
    \194\ 81 FR 24029 (April 25, 2016).
---------------------------------------------------------------------------

    For SI non-AO engines, Rule 4702 establishes NOX 
emission limits ranging from 11 to 75 ppmv, depending on the type of 
engine.\195\ According to Appendix C of the 2018 PM2.5 Plan, 
these NOX emission limits are at least as stringent as many 
analogous control requirements implemented in the Bay Area, Sacramento 
Metro, and Ventura County areas.\196\ We also note that the Rule 4702 
limits for these engines are at least as stringent as analogous 
requirements in the Feather River, Placer County, Mojave Desert, and 
San Diego areas.\197\
---------------------------------------------------------------------------

    \195\ SJVUAPCD Rule 4702, as amended November 14, 2013, section 
5.2.2 and tables 1 and 2.
    \196\ 2018 PM2.5 Plan, App. C, C-214 to C-221.
    \197\ Feather River AQMD Rule 3.22; Placer County APCD Rule 242; 
Mojave Desert AQMD Rule 1160; and San Diego APCD Rule 69.4.1.
---------------------------------------------------------------------------

    Some of the emission limits for specific types of SI non-AO engines 
in Rule 4702 are, however, less stringent than those implemented in the 
South Coast, El Dorado, and Antelope Valley areas for similar engines. 
Specifically, the SCAQMD has adopted an 11 ppmv limit for all IC 
engines;\198\ El Dorado has adopted a 25 ppmv limit for SI ``rich-
burn'' engines and a 65 ppmv limit for SI ``lean-burn'' engines (except 
those used exclusively in agricultural operations); \199\ and Antelope 
Valley has adopted a 36 ppmv limit for IC engines (except those used 
exclusively in agricultural operations).\200\ As explained in Appendix 
C of the 2018 PM2.5 Plan, the District considered the 
technical and economic feasibility of alternative control techniques 
for certain SI non-AO engines (e.g., waste gas engines, cyclic loaded 
field gas-fueled engines, limited use engines, two-stroke gaseous 
fueled engines, and lean-burn engines used in gas compression) that 
would lower the emission levels for these engines to 11 ppmv but found 
that these NOX controls are not feasible for implementation 
in the San Joaquin Valley at this time.\201\
---------------------------------------------------------------------------

    \198\ SCAQMD Rule 1110.2, as amended February 1, 2008.
    \199\ El Dorado County AQMD Rule 233, as amended June 2, 2006.
    \200\ Antelope Valley AQMD Rule 1110.2, as amended January 21, 
2003.
    \201\ 2018 PM2.5 Plan, App. C, C-221 to C-227.
---------------------------------------------------------------------------

    For SI AO engines, Rule 4702 establishes NOX emission 
limits ranging from 90 to 150 ppmv.\202\ These NOX emission 
limits are more stringent than analogous control requirements 
implemented in the Sacramento Metro, Placer County, El Dorado, and 
Antelope Valley areas, which exempt AO engines from control 
requirements altogether, and are equivalent to analogous control 
requirements implemented in the Mojave Desert area.\203\ The SCAQMD, 
however, has adopted an 11 ppmv NOX emission limit for all 
stationary SI and CI engines rated over 50 bhp, effective July 1, 2011, 
with limited exceptions for agricultural engines that meet certain 
conditions.\204\ Additionally, the Feather River Air Quality Management 
District (FRAQMD) Rule 3.22, as amended October 6, 2014, establishes 
NOX emission limits of 25 parts per million (ppm) and 65 ppm 
for rich-burn and lean-burn agricultural engines in southern FRAQMD, 
respectively, except for engines located at agricultural sources that 
emit less than 50% of the major source thresholds for regulated air 
pollutants and/or hazardous air pollutants.\205\ These NOX 
emission limits in SCAQMD Rule 1110.2 and FRAQMD Rule 3.22 thus appear 
to be more stringent in some respects than the 90 ppmv and 150 ppmv 
limits applicable to agricultural engines in SJVUAPCD Rule 4702. As of 
June 2016, staff at the FRAQMD were unaware of any stationary SI 
engines currently operating at agricultural facilities in the Feather 
River area that have demonstrated compliance with the 25 ppm or 65 ppm 
NOX emission limits in FRAQMD Rule 3.22.\206\ Nonetheless, 
because these NOX emission limits are approved into the 
California SIP,\207\ they are required as MSM if they can feasibly be 
implemented in the San Joaquin Valley.
---------------------------------------------------------------------------

    \202\ SJVUAPCD Rule 4702, as amended November 14, 2013, section 
5.2.3 and Table 3.
    \203\ SMAQMD Rule 412, as amended June 1, 1995; Placer County 
APCD Rule 242, as adopted April 10, 2003; El Dorado County AQMD Rule 
233, as amended June 2, 2006; Antelope Valley AQMD Rule 1110.2, as 
amended January 21, 2003; and Mojave Desert AQMD Rule 1160.1, as 
adopted January 23, 2012.
    \204\ SCAQMD Rule 1110.2, as amended February 1, 2008, section 
(d)(1) (referencing Tables I and II). Rule 1110.2 provides an 
exemption from the 11 ppmv emission limit for agricultural engines 
that meet EPA Tier 4 emission standards and either of two additional 
conditions: (1) The engine operator submits documentation to the 
SCAQMD, by the deadline for a permit application, that the 
applicable electric utility has rejected an application for an 
electrical line extension to the location of the engines, or (2) the 
SCAQMD determines that the operator does not qualify for funding 
under California Health and Safety Code Section 44229 to replace, 
retrofit or repower the engine. SCAQMD Rule 1110.2 at section 
(h)(9).
    \205\ FRAQMD Rule 3.22, as amended October 6, 2014, section D.1, 
Table 2 (South FRAQMD Emission Limits) and section B.1.e 
(Exemptions).
    \206\ Email dated June 2, 2016, from Alamjit Mangat, FRAQMD to 
Nicole Law, EPA Region IX, regarding ``Engines in FRAQMD'' (stating 
that all 423 agricultural engines currently operating in the Feather 
River area qualify for an exemption from the NOX emission 
limits in FRAQMD Rule 3.22). The 25 ppm and 65 ppm NOX 
emission limits in SIP-approved Rule 3.22 apply only to engines 
located at agricultural sources that emit at least 50% of the major 
source thresholds for regulated air pollutants and/or hazardous air 
pollutants. FRAQMD Rule 3.22, as amended October 6, 2014, section 
D.1, Table 2 (South FRAQMD Emission Limits) and section B.1.e 
(Exemptions).
    \207\ 80 FR 22646 (April 23, 2015) (final rule approving FRAQMD 
Rule 3.22 into California SIP).
---------------------------------------------------------------------------

    The District considered the technical and economic feasibility of 
alternative control techniques for SI AO engines that would lower the 
emission levels for certain engines to 11 ppmv but found that these 
NOX controls are not feasible for implementation within San 
Joaquin Valley's agricultural industry at this time.\208\ Based on our 
understanding that three natural gas-fired SI AO engines in the South 
Coast are currently subject to the 11 ppmv NOX emission 
limit in SCAQMD Rule 1110.2 and use nonselective catalytic reduction 
(NSCR, also called ``three-way catalysts'') control technology to 
comply with this emission limit,\209\ the EPA requested additional 
information from the District regarding the technological and economic 
feasibility of additional NOX control techniques for SI AO 
engines, and on October 7, 2019, the District submitted a document 
entitled ``Further Information for EPA Regarding the MSM Analysis for 
Agricultural Operation Engines'' (referred to herein as the ``AO Engine 
Additional Analysis'').\210\

[[Page 17402]]

According to the District, the NOX controls that would be 
necessary to achieve a 11 ppmv emission limit at SI AO engines in the 
San Joaquin Valley are not economically feasible because of factors 
such as increased fuel costs, increased engine maintenance costs, and 
the costs of engine overhaul/replacement,\211\ and installation of 
control equipment on an SI AO engine generally is not technologically 
feasible without substantial and costly engine retrofits.\212\ The AO 
Engine Additional Analysis explains the District's cost-effectiveness 
calculations.\213\ The District also provided information regarding 
technical feasibility challenges related to the specific type of 
workforce, and physical size and location of agricultural operations in 
the San Joaquin Valley.
---------------------------------------------------------------------------

    \208\ 2018 PM2.5 Plan, App. C, C-231 to C-238.
    \209\ 81 FR 69396, 69398 (October 6, 2016) (citing email dated 
May 3, 2016, from Kevin Orellana, SCAQMD to Nicole Law, EPA Region 
IX).
    \210\ Email dated October 7, 2019, from John Klassen, SJVUAPCD 
to Doris Lo, EPA Region IX, Subject: ``RE: Follow up questions on 
glass melting and IC engines for MSM analysis,'' attaching ``Further 
Information for EPA Regarding the MSM Analysis for Agricultural 
Operation Engines'' (``AO Engine Additional Analysis'').
    \211\ AO Engine Additional Analysis, 9-12.
    \212\ Id. at 10-11.
    \213\ Id. at 9-11.
---------------------------------------------------------------------------

    We note that the SCAQMD, like SJVUAPCD, has provided economic 
incentive grants for agricultural engine retrofits and replacement in 
recognition of unique economic and technical circumstances in the 
agricultural industry.\214\
---------------------------------------------------------------------------

    \214\ SCAQMD Final Staff Report for Rule 1110.2, May 2005, App. 
B (``Incentive Funding Available for Agricultural Engine Emission 
Reductions'').
---------------------------------------------------------------------------

    Finally, for compression-ignited IC engines (both those used in 
agricultural operations and those used in non-agricultural operations), 
Rule 4702 requires compliance by specified dates with EPA Tier 3 or 
Tier 4 NOX emission standards for non-road CI engines in 40 
CFR part 89 or part 1039, as applicable, or an 80 ppmv NOX 
emission limit, depending on engine type.\215\
---------------------------------------------------------------------------

    \215\ SJVUAPCD Rule 4702, as amended November 14, 2013, section 
5.2.4, Table 4, and section 3.37 (defining Tier 1, Tier 2, Tier 3, 
and Tier 4 engines).
---------------------------------------------------------------------------

Conservation Management Practices
    SJVUAPCD Rule 4550 (``Conservation Management Practices''), as 
adopted August 19, 2004, establishes requirements for owners and 
operators of agricultural sites to implement conservation management 
practices (CMPs) to control PM10 emissions from on-field 
crop and animal feeding operations.\216\ Under the rule, each owner/
operator of an agricultural site must select and implement a CMP for 
each category of operations, including unpaved roads and unpaved 
vehicle/equipment traffic areas, and submit a CMP application to the 
District for its review and approval.\217\ The EPA approved this rule 
into the California SIP on February 14, 2006.\218\
---------------------------------------------------------------------------

    \216\ SJVUAPCD Rule 4550, as adopted August 19, 2004.
    \217\ Id.
    \218\ 71 FR 7683 (February 14, 2006).
---------------------------------------------------------------------------

    According to Appendix C of the 2018 PM2.5 Plan, Rule 
4550 was the first rule of its kind in the nation to reduce fugitive 
particulate emissions from agricultural operations through 
implementation of conservation practices.\219\ The District compared 
the provisions of Rule 4550 to analogous regulations implemented by air 
agencies in other parts of California (Imperial County and South Coast) 
and in Arizona, and found that Rule 4550 is at least as stringent as 
each of these other regulations.\220\ We note that it is difficult to 
directly compare the requirements among these rules because of the 
widely varying rule structures and operations of the affected 
agricultural sites.
---------------------------------------------------------------------------

    \219\ 2018 PM2.5 Plan, App. C, C-196.
    \220\ Id. at C-202, C-203.
---------------------------------------------------------------------------

    The 2018 PM2.5 Plan states that additional CMPs and 
other controls for windblown dust would not substantially impact 
PM2.5 design values in the San Joaquin Valley because 
windblown dust events typically do not coincide with the winter period 
during which PM2.5 concentrations in the San Joaquin Valley 
are the highest.\221\ According to the District, PM2.5 
design values in the San Joaquin Valley are driven primarily by high 
winter-time concentrations, mostly due to organic carbon and the 
secondary formation of ammonium nitrate, while the geologic component 
of peak PM2.5 concentrations is a fraction (less than 6%) of 
the mass formed by secondary processes and other sources.\222\ 
Additionally, the District states that PM2.5 comprises a 
small fraction (approximately 6% to 12%) of total PM10 
emissions from agricultural field operations in the San Joaquin 
Valley.\223\
---------------------------------------------------------------------------

    \221\ Id. at C-200, C-201.
    \222\ Id. at C-201.
    \223\ Id. at C-200.
---------------------------------------------------------------------------

Commercial Charbroiling
    SJVUAPCD Rule 4692 (``Commercial Charbroiling''), as amended 
September 17, 2009, establishes control requirements to reduce 
PM10 (including PM2.5) and VOC emissions from 
chain-driven charbroilers.\224\ Specifically, the rule requires that 
chain-driven charbroilers be equipped and operated with a catalytic 
oxidizer with a control efficiency of at least 83% for PM10 
emissions and 86% for VOC emissions.\225\ The rule does not require 
controls for under-fired charbroilers (UFCs). The EPA approved the 
District's 2009 amendments to Rule 4692 into the California SIP on 
November 3, 2011.\226\
---------------------------------------------------------------------------

    \224\ SJVUAPCD Rule 4692, as amended September 17, 2009.
    \225\ Id.
    \226\ 76 FR 68103.
---------------------------------------------------------------------------

    Appendix C of the 2018 PM2.5 Plan includes a comparison 
of the requirements in Rule 4692 to analogous requirements for chain-
driven charbroilers implemented by the SCAQMD, Ventura County Air 
Pollution Control District (VCAPCD), BAAQMD, and New York Department of 
Environmental Protection (NYDEP) and found no requirements for chain-
driven charbroilers in these rules that are more stringent than those 
contained in Rule 4692.\227\ With respect to UFCs, the District noted 
that two regulations, the BAAQMD's Regulation 6 Rule 2 and title 24, 
section 24-149.4 of the New York City Administrative Code, contain 
control requirements for UFCs. According to the District, however, the 
majority of the UFCs in the Bay Area are not subject to the 
requirements for UFCs in BAAQMD Regulation 6 Rule 2 because they fall 
below the rule's applicability thresholds, and the BAAQMD has not 
enforced its UFC requirements because no control technologies have yet 
been certified.\228\ Similarly, the District states in Appendix C of 
the 2018 PM2.5 Plan that NYDEP staff are in the introductory 
stages of establishing an inventory and planning for inspections at 
charbroiling facilities, and that installation of controls for new UFCs 
is not yet required under title 24, section 24-149.4 of the New York 
City Administrative Code.\229\ The SJVUAPCD therefore concluded that 
control requirements for UFCs are not technologically and economically 
feasible at this time.
---------------------------------------------------------------------------

    \227\ 2018 PM2.5 Plan, App. C, C-205 to C-208.
    \228\ Id. at C-206. We note that the BAAQMD and NYDEP 
charbroiler rules have not been approved into the California SIP and 
New York SIP, respectively.
    \229\ Id.
---------------------------------------------------------------------------

    We are not aware of requirements for chain-driven charbroilers in 
other areas that are more stringent than the requirements of Rule 4692. 
Although the BAAQMD and NYDEP implement rules that require controls for 
UFCs, neither agency has yet confirmed that any regulated sources have 
successfully installed and operated certified UFC control 
technologies.\230\ Staff at the

[[Page 17403]]

BAAQMD recently noted that electrostatic precipitators (ESPs) have been 
installed in commercial kitchens in San Francisco and San Jose but that 
the BAAQMD has not yet enforced control requirements for UFCs.\231\ We 
note that the 2018 PM2.5 Plan identifies several restaurants 
inside and outside of the San Joaquin Valley that have installed UFC 
control technologies, and that these installations may inform the 
District's ongoing feasibility analyses.\232\ For example, the District 
has implemented a first-of-its-kind pilot project to install and assess 
the feasibility of UFC controls at an operating restaurant.\233\ We 
encourage the District to continue monitoring the operation of these 
control technologies to determine whether they can feasibly be 
implemented at other charbroiling sources in the San Joaquin Valley.
---------------------------------------------------------------------------

    \230\ Email dated July 11, 2019, from Stanley Tong, EPA Region 
IX to Krishnan Balakrishnan, BAAQMD, Subject: ``Underfired 
charbroiler updates'' and email dated June 17, 2019, from Ronald 
Vaughn, NYDEP to Stanley Tong, EPA Region IX, Subject: ``RE New 
Charbroiler Registrations NYC.''
    \231\ Email dated January 9, 2020, from Virginia Lau, BAAQMD to 
Stanley Tong, EPA Region IX, Subject: ``RE: Underfired charbroiler--
Q: SJ discussion about BA rule'' (noting that the BAAQMD has 
conducted enforcement inspections concerning food throughput and 
grill size).
    \232\ 2018 PM2.5 Plan, App. C, C-209.
    \233\ Id. at App. E, E-20.
---------------------------------------------------------------------------

    The District revised Rule 4692 on June 21, 2018, to require owners 
and operators of commercial cooking operations with UFCs to submit, by 
January 1, 2019, a one-time informational report providing information 
about the UFC and its operations--including, e.g., information about 
the cooking surface area, type and quantity of meat cooked on the UFC 
on a weekly basis during the previous 12-month period, daily operating 
hours, and the manufacturer and model number of any installed pollution 
control device designed to reduce particulates, kitchen smoke, or 
odor.\234\ The revisions to Rule 4692 also require such owners and 
operators to register with the District and keep weekly records 
relating to the quantity of meat cooked, but exempt from the 
registration and recordkeeping requirements UFCs that cook quantities 
of meat below certain thresholds provided the owner or operator 
complied with the one-time informational reporting requirement. CARB 
submitted the amended rule to the EPA on November 21, 2018, via a 
letter dated November 16, 2018.\235\
---------------------------------------------------------------------------

    \234\ SJVUAPCD Rule 4692, as amended June 21, 2018. The 
revisions to Rule 4692 provide that commercial cooking operations 
with UFCs that are operated outdoors and are not connected to an 
exhaust hood or other form of ventilation system are exempt from the 
requirements of the rule. Id. at sections 3.9 and 4.3.
    \235\ Letter dated November 16, 2018, from Richard W. Corey, 
Executive Officer, CARB, to Mike Stoker, Regional Administrator, EPA 
Region IX (transmitting amended Rule 4692).
---------------------------------------------------------------------------

Stationary Gas Turbines
    SJVUAPCD Rule 4703 (``Stationary Gas Turbines''), as amended 
September 20, 2007, establishes NOX emission limits and 
related operational requirements for stationary gas turbines with 
greater than 0.3 MW capacity or a maximum heat input rating of more 
than 3 million Btu/hr.\236\ The NOX emission limits in the 
rule range from 3 to 25 ppm for gas-fired operations and from 25 to 42 
ppm for liquid-fired operations.\237\ These units operate primarily in 
the oil and gas production and utility industries, with some also 
operating in manufacturing and government facilities.\238\ The EPA 
approved this rule into the California SIP on October 21, 2009.\239\
---------------------------------------------------------------------------

    \236\ SJVUAPCD Rule 4703, as amended September 20, 2007.
    \237\ Id. at Table 5-3.
    \238\ 2018 PM2.5 Plan, App. C, C-243 to C-247.
    \239\ 74 FR 53888 (October 21, 2009).
---------------------------------------------------------------------------

    According to information provided in Appendix C of the 2018 
PM2.5 Plan, the NOX emission limits in Rule 4703 
are at least as stringent as analogous control requirements implemented 
in the Bay Area, South Coast, and Ventura County.\240\ We note that the 
SCAQMD recently revised its rule for stationary gas turbines (Rule 
1134) to establish, among other things, a NOX emission limit 
of 2 ppmv for natural gas-fired combined cycle turbines, which is more 
stringent than the 3 ppmv limit in SJVUAPCD Rule 4703 for these 
units.\241\ Because the compliance date for this requirement in SCAQMD 
Rule 1134 is December 31, 2023, however, it is not clear that the 
controls necessary to achieve a 2 ppmv emission level are 
technologically and economically feasible at this time.
---------------------------------------------------------------------------

    \240\ 2018 PM2.5 Plan, App. C, C-243 to C-247.
    \241\ SCAQMD Rule 1134, as amended April 5, 2019, section (d) 
and table I (``Emission Limits for Stationary Gas Turbines'').
---------------------------------------------------------------------------

Wood Burning Fireplaces and Wood Burning Heaters
    SJVUAPCD Rule 4901 (``Wood Burning Fireplaces and Wood Burning 
Heaters''), as amended June 20, 2019, is designed to limit emissions of 
PM, including PM2.5 and PM10, and other 
pollutants generated by the use of wood burning fireplaces, wood 
burning heaters, and outdoor wood burning devices. The rule establishes 
requirements for the sale/transfer, operation, and installation of wood 
burning devices and on the advertising of wood for sale within the San 
Joaquin Valley. The EPA proposed to approve the District's 2019 
amendments to the rule into the SIP on January 9, 2020.\242\
---------------------------------------------------------------------------

    \242\ 85 FR 1131 (January 9, 2020).
---------------------------------------------------------------------------

    As part of the evaluation supporting our proposed approval,\243\ we 
found that Rule 4901 and the related Check Before You Burn program 
(http://valleyair.org/rule4901) implemented by the District provide for 
a comprehensive residential wood smoke program that incorporates all of 
the elements outlined in EPA's ``Strategies for Reducing Wood Smoke.'' 
\244\ Among the key elements of the rule are a wood burning curtailment 
program (triggered by forecasted PM2.5 concentrations for 
the next day), opacity and visible emission limits, requirements 
regarding wood moisture content, removal of uncertified wood burning 
stoves upon home resale, restrictions on installation of wood burning 
devices, requirement that all wood burning stoves sold or transferred 
within the District meet New Source Performance Standards (NSPS), a 
wood burning change-out program and education and outreach. In the 
Technical Support Document to support our separate proposal on Rule 
4901, we compare this rule to analogous rules implemented elsewhere and 
conclude that Rule 4901, as a whole, is as or more stringent than 
analogous local, state, and federal rules and guidance.\245\
---------------------------------------------------------------------------

    \243\ Technical Support Document for the EPA's Proposed 
Rulemaking for the California State Implementation Plan, San Joaquin 
Valley Unified Air Pollution Control District Rule 4901 (``Wood 
Burning Fireplaces and Wood Burning Heaters''), December 2019.
    \244\ Strategies for Reducing Wood Smoke, EPA-456/B-13-01, March 
2013.
    \245\ Id. The SJVUAPCD provides its comparisons of Rule 4901 to 
analogous rules implemented elsewhere in Appendix C of the Plan. 
2018 PM2.5 Plan, App. C, C-259 to C-280.
---------------------------------------------------------------------------

    Of particular relevance for reducing PM2.5 emissions, 
Rule 4901 includes a tiered mandatory curtailment program that 
establishes different curtailment thresholds based on the type of 
device and county. During a level one episodic woodburning curtailment, 
operation of wood burning fireplaces and unregistered wood burning 
heaters is prohibited, but properly operated, registered \246\ wood 
burning devices may be used. During a level two episodic woodburning 
curtailment, operation of any wood burning device is prohibited. 
However, the rule includes an exemption from the curtailment provisions 
for (1) locations where natural gas service is not available and (2) 
residences for which a wood burning

[[Page 17404]]

fireplace or wood burning heater is the sole available source of heat. 
In the ``hot spot'' counties of Madera, Fresno, and Kern, the level one 
PM2.5 threshold is 12 [mu]g/m\3\, and the level two 
PM2.5 threshold is 35 [mu]g/m\3\. In the remaining counties 
in the District (San Joaquin, Stanislaus, Merced, Kings, and Tulare), 
the level one PM2.5 threshold is 20 [mu]g/m\3\, and the 
level two PM2.5 threshold is 65 [mu]g/m\3\. These 
curtailment thresholds in Rule 4901 are collectively as stringent as or 
more stringent than those in any other rule.
---------------------------------------------------------------------------

    \246\ In order to be registered, a device must either be 
certified under the NSPS at time of purchase or installation and at 
least as stringent as Phase II requirements or be a pellet-fueled 
wood burning heater exempt from EPA certification requirements at 
the time of purchase or installation. The rule includes requirements 
for documentation and inspection to verify compliance with these 
standards.
---------------------------------------------------------------------------

b. State Measures for Mobile Sources
    Mobile source categories for which CARB has primary responsibility 
for reducing emissions in California include most new and existing on- 
and non-road engines and vehicles and motor vehicle fuels. The 2018 
PM2.5 Plan's BACM and MSM demonstration provides a general 
description of CARB's key mobile source programs and regulations and a 
comprehensive table listing on-road and non-road mobile source 
regulatory actions taken by CARB since 1985.\247\ Given the need for 
substantial emissions reductions from mobile sources to meet the NAAQS 
in California's nonattainment areas, CARB has established stringent 
control measures for on-road and non-road mobile sources and the fuels 
that power them. California has unique authority under CAA section 209 
(subject to a waiver by the EPA) to adopt and implement new emission 
standards for many categories of on-road vehicles and engines, and new 
and in-use non-road vehicles and engines. The EPA has approved such 
mobile source regulations for which waiver authorizations have been 
issued as revisions to the California SIP.\248\
---------------------------------------------------------------------------

    \247\ 2018 PM2.5 Plan, App. D, Table 17.
    \248\ See, e.g., 81 FR 39424 (June 16, 2016), 82 FR 14447 (March 
21, 2017), and 83 FR 23232 (May 18, 2018).
---------------------------------------------------------------------------

    CARB's mobile source program extends beyond regulations that are 
subject to the waiver or authorization process set forth in CAA section 
209 to include standards and other requirements to control emissions 
from in-use heavy-duty trucks and buses, gasoline and diesel fuel 
specifications, and many other types of mobile sources. Generally, 
these regulations have also been submitted and approved as revisions to 
the California SIP.\249\
---------------------------------------------------------------------------

    \249\ See, e.g., the EPA's approval of standards and other 
requirements to control emissions from in-use heavy-duty diesel-
powered trucks, at 77 FR 20308 (April 4, 2012), revisions to the 
California on-road reformulated gasoline and diesel fuel regulations 
at 75 FR 26653 (May 12, 2010), and revisions to the California motor 
vehicle inspection and maintenance program at 75 FR 38023 (July 1, 
2010).
---------------------------------------------------------------------------

    During its development of the Valley State SIP Strategy, CARB 
identified measures that would achieve additional NOX and 
direct PM2.5 emissions reductions from sources under CARB 
jurisdiction, including more stringent in-use performance standards for 
heavy-duty vehicles, a low-NOX engine standard for vehicles 
with new heavy-duty engines, and a low-emission diesel fuel 
requirement.\250\ The Valley State SIP Strategy includes a commitment 
by CARB to bring a list of defined measures to the Board for action 
according to the schedule provided in Table 7 of the Valley State SIP 
Strategy.\251\
---------------------------------------------------------------------------

    \250\ Valley State SIP Strategy, Chapter 2 (``Measures''), 2018 
PM2.5 Plan, section 4.4 and App. D, Chapter IV 
(``Identification and Evaluation of Potential Measures'').
    \251\ CARB Resolution 18-49 (October 25, 2018), 5.
---------------------------------------------------------------------------

    We find that the process conducted by CARB to develop the Valley 
State SIP Strategy was reasonably designed to identify additional 
available measures within CARB's jurisdiction, and that CARB's programs 
constitute the most stringent emission control programs currently 
available for the mobile source and fuels categories, taking into 
account economic and technological feasibility.
c. Local Jurisdiction Transportation Control Measures (TCMs)
    TCMs are projects that reduce air pollutants from transportation 
sources by reducing vehicle use, traffic congestion, or vehicle miles 
traveled. TCMs are currently being implemented in the San Joaquin 
Valley as part of the Congestion Mitigation and Air Quality cost 
effectiveness policy adopted by the eight local jurisdiction MPOs and 
in the development of each Regional Transportation Plan (RTP). The 
Congestion Mitigation and Air Quality policy, which is included in a 
number of the District's prior attainment plan submissions for the 
ozone and PM2.5 NAAQS, provides a standardized process for 
distributing 20 percent of the Congestion Mitigation and Air Quality 
funds to projects that meet a minimum cost effectiveness threshold 
beginning in fiscal year 2011. The MPOs revisited the minimum cost 
effectiveness standard during the development of their 2018 RTPs and 
2019 Federal Transportation Improvement Program and concluded that they 
were implementing all reasonable transportation control measures.\252\ 
Appendix D of the District's ``2016 Ozone Plan for 2008 8-Hour Ozone 
Standard,'' adopted June 16, 2016, contains a listing of adopted TCMs 
for the San Joaquin Valley.\253\
---------------------------------------------------------------------------

    \252\ 2018 PM2.5 Plan, App. D, D-127.
    \253\ Id. and SJVUAPCD, ``2016 Ozone Plan for 2008 8-Hour Ozone 
Standard'' (adopted June 16, 2016), App. D, Attachment D, tables D-
10 through D-17.
---------------------------------------------------------------------------

d. Conclusion and Proposed Action
    We find that the evaluation process followed by CARB and the 
District in the SJV PM2.5 Plan to identify potential BACM 
and MSM were generally consistent with the requirements of the 
PM2.5 SIP Requirements Rule, the State's and District's 
evaluation of potential measures is appropriate, and the State and 
District have provided reasoned justifications for their rejection of 
potential measures based on technological or economic infeasibility. We 
also agree with the District's conclusion that all reasonable TCMs are 
being implemented in the San Joaquin Valley and propose to find that 
these TCMs implement BACM and MSM for transportation sources.
    For the foregoing reasons, we propose to find that the SJV 
PM2.5 Plan provides for the implementation of BACM for 
sources of direct PM2.5 and NOX as expeditiously 
as practicable and no later than December 31, 2019, and for the 
implementation of MSM for such sources as expeditiously as practicable 
and no later than December 31, 2023, in accordance with the 
requirements of CAA sections 189(b)(1)(B) and 188(e).

D. Extension of Serious Area Attainment Date Under CAA Section 188(e)

    In this section of the preamble, we present our evaluation of the 
State's request to extend the Serious area attainment date from 
December 31, 2019, to December 31, 2024, under CAA section 188(e) and, 
given the section 188(e) requirement to demonstrate expeditious 
attainment of the NAAQS, our evaluation of the SJV PM2.5 
Plan's attainment demonstration, including the Plan's air quality 
modeling approach and results and control strategy.
1. Demonstration That Attainment by Serious Area Attainment Date Is 
Impracticable
a. Summary of State's Impracticability Demonstration
    The SJV PM2.5 Plan includes a demonstration, based on 
air quality modeling, that even with the implementation of BACM and 
BACT for all appropriate sources, attainment by December 31, 2019, is 
not practicable. The impracticability demonstration is included in 
Appendix K of the 2018 PM2.5 Plan.

[[Page 17405]]

    Table 26 in Appendix K presents base year and modeled 2020 future 
year 24-hour average PM2.5 concentrations at 15 
PM2.5 monitoring sites in the San Joaquin Valley 
nonattainment area. The demonstration is summarized in Table 3.

  Table 3--Impracticability Demonstration, 24-Hour Average PM2.5 Design
                          Value Concentrations
                             [[micro]g/m\3\]
------------------------------------------------------------------------
                                                         2020 (projected
           Monitoring Site            2013 (base year)    future year)
------------------------------------------------------------------------
Bakersfield--California.............              64.1              47.6
Fresno--Garland.....................              60.0              44.3
Hanford.............................              60.0              43.7
Fresno--Hamilton & Winery...........              59.3              45.6
Clovis..............................              55.8              41.1
Visalia.............................              55.5              42.8
Bakersfield--Planz..................              55.5              41.2
Madera..............................              51.0              38.9
Turlock.............................              50.7              37.8
Modesto.............................              47.9              35.8
Merced--Main Street.................              46.9              32.9
Stockton............................              42.0              33.5
Merced--S Coffee....................              41.1              30.0
Manteca.............................              36.9              30.1
Tranquility.........................              29.5              21.5
------------------------------------------------------------------------
Source: 2018 PM2.5 Plan, Appendix K, Table 26.

b. EPA's Evaluation and Proposed Action
    The impracticability demonstration in the SJV PM2.5 Plan is based 
on air quality modeling that is generally consistent with applicable 
EPA guidance. We find the modeling, described in section IV.D.4.a of 
this preamble, adequate to support the impracticability demonstration 
in the Plan. We note that the modeled year of the impracticability 
demonstration is 2020, the year following the December 31, 2019 
attainment date. However, as the projected 24-hour average 
concentration in 2020 is 48 [micro]g/m\3\, well above the 35 [micro]g/
m\3\ level of the 2006 24-hour PM2.5 NAAQS, we find it 
reasonable to conclude based on this evaluation that attainment by the 
end of 2019 is impracticable.
    In addition to the information in the 2018 PM2.5 Plan, 
we have reviewed recent PM2.5 monitoring data from the San 
Joaquin Valley. These data show that 24-hour average PM2.5 
levels in the San Joaquin Valley, with a 2016-2018 design value of 65 
[micro]g/m\3\, continue to be above the 35 [micro]g/m\3\ level of the 
2006 24-hour PM2.5 standard. Recent trends in annual 
PM2.5 levels in the San Joaquin Valley are not consistent 
with a projection of attainment by the end of 2019. A more detailed 
analysis, including 24-hour PM2.5 trend data in the San 
Joaquin Valley for years 2004-2018, is contained in section II of the 
EPA's General Evaluation TSD.\254\
---------------------------------------------------------------------------

    \254\ See also, Attachment A to the EPA's General Evaluation 
TSD, ``Practicability of San Joaquin Valley Attaining 2006 24-hour 
PM2.5 NAAQS by December 31, 2019,'' October 9, 2019.
---------------------------------------------------------------------------

    We discuss in section IV.C of this proposed rule our evaluation of 
the BACM and BACT demonstration and the bases for our proposal to find 
that the SJV PM2.5 Plan provides for the implementation of 
all BACM and BACT by the statutory implementation deadline. Based on 
our evaluation of the State's impracticability demonstration, including 
the demonstration concerning BACM and BACT, and our review of the 
available ambient air quality data, we propose to approve the State's 
demonstration in the 2018 PM2.5 Plan that attainment of the 
2006 24-hour PM2.5 NAAQS in the San Joaquin Valley by the 
Serious area attainment date of December 31, 2019, is impracticable.
2. Compliance With All Requirements and Commitments in the 
Implementation Plan
    We interpret this criterion to mean that the State has implemented 
the control measures and commitments in the plan revisions it has 
submitted to address the applicable requirements in CAA sections 172 
and 189 for PM2.5 nonattainment areas. For the San Joaquin 
Valley, the EPA has approved the control measure requirements and 
commitments of the 2008 PM2.5 Plan (for the 1997 
PM2.5 NAAQS) and the 2012 PM2.5 Plan and 
Supplement (for the 2006 PM2.5 NAAQS) into the California 
SIP. The EPA has not yet taken action on the State's SIP revisions for 
the 2012 PM2.5 NAAQS. Therefore, we describe below the 
State's and District's implementation of the control measures and 
commitments for the 1997 PM2.5 NAAQS and 2006 
PM2.5 NAAQS. For more detail on our evaluation for the 1997 
PM2.5 NAAQS, please refer to section III of the EPA's 
General Evaluation TSD.
a. Requirements and Commitments for the 1997 PM2.5 NAAQS
    Between 2007 and 2011, California made six SIP submissions to 
address nonattainment area planning requirements for the 1997 
PM2.5 NAAQS in the SJV,\255\ which we refer to collectively 
as the ``2008 PM2.5 Plan.'' On November 9, 2011, the EPA 
approved most elements of the 2008 PM2.5 Plan, including 
commitments by CARB and the SJVUAPCD to take specific actions with 
respect to identified control measures and to achieve specific amounts 
of direct PM2.5, NOX, and SOX emission 
reductions by 2014.\256\
---------------------------------------------------------------------------

    \255\ 76 FR 69896, n. 2 (November 9, 2011).
    \256\ Id. at 69926 (codified at 40 CFR 52.220(c)(356)(ii)(B)(2), 
52.220(c)(392)(ii)(A)(2), and 52.220(c)(395)(ii)(A)(2).
---------------------------------------------------------------------------

    The specific State and District commitments that the EPA approved 
into the California SIP as part of the 2008 PM2.5 Plan are 
as follows:
    (1) A commitment by CARB to propose specific measures identified in 
Appendix B of the ``Progress Report on Implementation of 
PM2.5 State Implementation Plans (SIP) for the South Coast 
and San Joaquin Valley Air Basins and Proposed SIP Revisions,'' dated 
April 28, 2011 (``2011 Progress

[[Page 17406]]

Report''), in accordance with the timetable specified therein; \257\
---------------------------------------------------------------------------

    \257\ 40 CFR 52.220(c)(395)(ii)(A)(2), CARB Resolution No. 07-
28, Attachment B (September 27, 2007), CARB Resolution No. 09-34 
(April 24, 2009), and CARB Resolution No. 11-24 (April 28, 2011); 
see also 76 FR 69896 at 69921-69922, Table 2.
---------------------------------------------------------------------------

    (2) A commitment by the District to ``adopt and implement the rules 
and measures in the 2008 PM2.5 Plan'' in accordance with the 
timetable specified in Table 6-2 of the 2008 PM2.5 Plan, as 
amended June 17, 2010, and to submit these rules and measures to CARB 
for transmittal to EPA as SIP revisions; \258\
---------------------------------------------------------------------------

    \258\ 40 CFR 52.220(c)(392)(ii)(A)(2), SJVUAPCD Governing Board 
Resolution No. 08-04-10 (April 30, 2008), and SJVUAPCD Governing 
Board Resolution No. 10-06-18 (June 17, 2010); see also 76 FR 69896 
at 69921, Table 1.
---------------------------------------------------------------------------

    (3) A commitment by CARB to achieve a total of 17.1 tons per day 
(tpd) of NOX emission reductions and 2.3 tpd of direct 
PM2.5 emission reductions by 2014 as described in CARB 
Resolution No. 07-28, Attachment B, as amended in 2009 and 2011; \259\ 
and
---------------------------------------------------------------------------

    \259\ 40 CFR 52.220(c)(356)(ii)(B)(2).
---------------------------------------------------------------------------

    (4) A commitment by the District to achieve a total of 8.97 tpd of 
NOX emission reductions, 6.7 tpd of direct PM2.5 
emission reductions, and 0.92 tpd of SOX emission reductions 
by 2014 as described in Table 6-3a, Table 6-3b, and Table 6-3c, 
respectively, of the 2008 PM2.5 Plan.\260\
---------------------------------------------------------------------------

    \260\ 40 CFR 52.220(c)(392)(ii)(A)(2).
---------------------------------------------------------------------------

    As of November 9, 2011, the date of the EPA's final action on the 
2008 PM2.5 Plan, CARB and the District had each satisfied 
substantial portions of these control measure and emission reduction 
commitments. Specifically, CARB had proposed action on six of the seven 
measures it had committed to propose for Board consideration, leaving 
one additional measure that was scheduled for proposal in 2013 (``New 
Emissions Standards for Recreational Boats'').\261\ The District had 
adopted 12 of the 13 measures it had committed to adopt and implement, 
leaving one additional measure that was scheduled for adoption in 2014, 
amendments to Rule 4905 (``Natural Gas-Fired, Fan-Type Central 
Furnaces'').\262\ Finally, together CARB and the SJVUAPCD had achieved 
all of the SOX emission reduction commitments and 
substantial portions of the direct PM2.5 and NOX 
emission reduction commitments through implementation of State and 
District control strategy measures, leaving 3.0 tpd of direct 
PM2.5 emission reductions and 12.9 tpd of NOX 
emission reductions yet to be achieved by the beginning of 2014.\263\
---------------------------------------------------------------------------

    \261\ 76 FR 69896, 69922, Table 2 (``2007 State Strategy Defined 
Measures Schedule for Consideration and Current Status'').
    \262\ Id. at 69921, Table 1 (``San Joaquin Valley Air Pollution 
Control District 2008 PM2.5 Plan Specific Rule 
Commitments'').
    \263\ Id. at 69923, Table 4 (``Reductions Needed for Attainment 
Remaining as Commitments Based on SIP-Creditable Measures'').
---------------------------------------------------------------------------

    Subsequently, CARB submitted a staff report, entitled ``Review of 
San Joaquin Valley PM2.5 State Implementation Plan'' (``2015 
CARB Compliance Demonstration''), that contains CARB's demonstration 
that both CARB and the District have satisfied the commitments in the 
2008 PM2.5 Plan that remained outstanding as of November 9, 
2011, as follows.\264\ First, on January 22, 2015, the District adopted 
amendments to Rule 4905 and on April 7, 2015, CARB submitted this rule 
to the EPA as a revision to the California SIP.\265\ Second, on 
February 19, 2015, CARB proposed for Board consideration, and the Board 
adopted, new emission standards for recreational boats entitled 
``Evaporative Emissions Control Requirements for Spark-Ignition Marine 
Watercraft.'' \266\ These State and District rulemaking actions 
satisfied the last remaining control measure commitments in the 2008 
PM2.5 Plan. All of these measures have been submitted to the 
EPA and approved into the California SIP, as summarized in Table III-A 
of EPA's General Evaluation TSD.
---------------------------------------------------------------------------

    \264\ CARB, ``Review of San Joaquin Valley PM2.5 
State Implementation Plan,'' released April 20, 2015 (``2015 CARB 
Compliance Demonstration''), transmitted by email dated February 5, 
2020, from Michael Benjamin, CARB to Meredith Kurpius, EPA Region 
IX, 17-22 and App. B.
    \265\ 2015 CARB Compliance Demonstration at 19, Table 7 and 
letter dated April 7, 2015, from Richard Corey, Executive Officer, 
CARB, to Jared Blumenfeld, Regional Administrator, EPA Region 9 
(transmitting air district regulations to the EPA as California SIP 
revisions).
    \266\ 2015 CARB Compliance Demonstration at 20, Table 8 and 
CARB, Resolution 15-3, ``Evaporative Emissions Control Requirements 
for Spark-Ignition Marine Watercraft,'' February 19, 2015, available 
at http://www.arb.ca.gov/regact/2015/simw2015/simw2015.htm.
---------------------------------------------------------------------------

    With respect to the remaining emission reduction commitments (also 
called ``aggregate tonnage commitments''), the 2015 CARB Compliance 
Demonstration, as amended by CARB's ``Technical Clarifications to the 
2015 San Joaquin Valley PM2.5 State Implementation Plan'' 
(``Technical Clarifications''), identifies nine State and District 
control measures that, according to CARB, achieved emission reductions 
beyond those already credited towards the 2008 PM2.5 Plan 
and satisfy the State's remaining 2014 emission reduction 
obligations.\267\ We have reviewed the State's demonstration with 
respect to each of these nine measures and propose to find that all but 
one achieved emission reductions that may be credited towards the 
remaining 2014 emission reduction obligation, because the State has 
adequately documented its bases for concluding that each measure either 
contains enforceable, SIP-approved requirements or otherwise achieved 
specified amounts of emission reductions by January 1, 2014. The one 
measure identified in the 2015 CARB Compliance Demonstration that did 
not achieve any SIP-creditable emission reductions is the District's 
Rule 9510 (``Indirect Source Review'').\268\ The EPA's General 
Evaluation TSD contains a more detailed evaluation of each of the eight 
measures that we are proposing to credit toward the emission reduction 
commitments in the 2008 PM2.5 Plan.
---------------------------------------------------------------------------

    \267\ 2015 CARB Compliance Demonstration at 21-22 and CARB, 
``Technical Clarifications to the 2015 San Joaquin Valley 
PM2.5 State Implementation Plan,'' transmitted by email 
dated February 5, 2020, from Michael Benjamin, CARB to Meredith 
Kurpius, EPA Region IX, 1-4.
    \268\ The EPA approved SJVUAPCD Rule 9510, as adopted December 
15, 2005, into the California SIP on May 9, 2011 but identified a 
number of concerns about the enforceability of the rule's provisions 
that the District would need to resolve before relying on this rule 
for credit in an attainment plan. 76 FR 26609 (May 9, 2011).
---------------------------------------------------------------------------

    According to the 2015 CARB Compliance Demonstration and Technical 
Clarifications, implementation of these control measures achieved, by 
the beginning of 2014, 26.4 tpd of additional NOX emission 
reductions and 2.1 tpd of direct PM2.5 emission reductions 
beyond those already credited toward the 2008 PM2.5 
Plan.\269\ These NOX emission reductions exceeded the 
State's outstanding NOX commitment (12.9 tpd) by 13.9 tpd, 
and the direct PM2.5 emission reductions fell short of the 
State's outstanding PM2.5 commitment (3.0 tpd) by 0.9 
tpd.\270\ Citing air quality modeling conducted as part of the 2008 
PM2.5 Plan, CARB stated that a reduction of 9 tpd of 
NOX emissions provides an air quality improvement equivalent 
to a 1 tpd reduction in directly emitted PM2.5. On this 
basis, CARB concluded that the approximately 13 tpd of surplus 
NOX reductions achieved through implementation of the 
identified State and District measures would adequately cover the 0.9 
tpd shortfall in required reductions of direct PM2.5.\271\
---------------------------------------------------------------------------

    \269\ 2015 CARB Compliance Demonstration at 21-22 and Technical 
Clarifications at 1-4.
    \270\ Id.
    \271\ Id.
---------------------------------------------------------------------------

    We find the technical bases for a 9:1 NOX for direct 
PM2.5 trading ratio are generally sound and therefore 
propose to use this trading ratio to credit the State with an 
additional 1.07 tpd of PM2.5 emission reduction, rounding to

[[Page 17407]]

the nearest hundredth (based on 9.63 tpd of ``excess'' NOX 
emission reductions) toward its outstanding 2014 commitment.\272\
---------------------------------------------------------------------------

    \272\ For further discussion of our evaluation of the 9:1 
NOX to direct PM2.5 trading ratio for purposes 
of the aggregate commitment, please see section IV of the EPA's 
General Evaluation TSD.

 Table 4--2008 PM2.5 Plan Aggregate Commitment--EPA Proposed Emission Reduction Credit for Measures in the 2015
                                          CARB Compliance Demonstration
----------------------------------------------------------------------------------------------------------------
                                                                                     2014 Emission reductions
                                                                                       (annual average tpd)
                                                         Measure                 -------------------------------
                                                                                                   Direct PM2.5
                                                                                        NOX
----------------------------------------------------------------------------------------------------------------
A.....................................  Rule 4320 (``Advanced Emission Reduction             1.8             0.0
                                         Options for Boilers, Steam Generators,
                                         and Process Heaters Greater than 5.0
                                         MMBtu/hr'').
B.....................................  Rule 9510 (``Indirect Source Review'')..             0.0             0.0
C.....................................  Woodstove Replacements..................             0.0             0.1
D.....................................  District Funded Incentive-Based Emission             1.5             0.1
                                         Reduction Measures.
E.....................................  Rule 9410 (``Employer Based Trip                     0.3             0.0
                                         Reduction'').
F.....................................  Rule 4901 (``Wood Burning Fireplaces and             0.0             1.3
                                         Wood Burning Heaters'').
G.....................................  State Funded Incentive-Based Emission                5.0            0.13
                                         Reduction Measures \a\.
H.....................................  CARB Cleaner In-Use Heavy Duty Trucks               11.5             0.1
                                         Measure.
I.....................................  CARB Portable Equipment Registration                 2.5             0.2
                                         Program (PERP) and Portable Engine ATCM.
J.....................................  TOTAL SIP-Creditable Emission Reductions            22.6            1.93
                                         from State and District Measures (Sum
                                         of A through I).
K.....................................  NOX to PM2.5 Emissions Equivalence at              -9.63            1.07
                                         9:1 Ratio.
L.....................................  TOTAL Emission Reductions Achieved (J+K)           12.97             3.0
----------------------------------------------------------------------------------------------------------------
\a\ On August 12, 2016, the EPA finalized a limited approval and limited disapproval of CARB's demonstration
  concerning the emission reductions achieved by the State-Funded Emission Reduction Measure (also referred to
  as the ``Emission Reduction Report''). 81 FR 53300. As part of that action, the EPA determined that the
  incentive projects identified in the Emission Reduction Report achieved a total of 4.971 tpd of NOX emission
  reductions and 0.134 tpd of direct PM2.5 emission reductions by the beginning of 2014, slightly less than the
  7.8 tpd of NOX emission reductions and 0.2 tpd of direct PM2.5 emission reductions that CARB had identified in
  this submission. Id. at 53306.

    In sum, the CARB Compliance Demonstration and Technical 
Clarifications demonstrate that implementation of State and District 
measures achieved a total of 12.97 tpd of NOX emission 
reductions and 3.0 tpd of direct PM2.5 emission reductions 
that have not previously been credited as part of the attainment 
demonstration in the 2008 PM2.5 Plan and that may, 
therefore, be credited toward the State's outstanding obligation to 
achieve 12.9 tpd of NOX emission reductions and 3.0 tpd of 
direct PM2.5 emission reductions by the beginning of 2014.
    Based on these evaluations, we propose to find that the State has 
complied with all requirements and commitments pertaining to the San 
Joaquin Valley nonattainment area in the implementation plan for the 
1997 PM2.5 NAAQS.
b. Requirements and Commitments for the 2006 PM2.5 NAAQS
    In 2013 and 2014, California made two SIP submissions to address 
nonattainment area planning requirements for the 2006 PM2.5 
NAAQS in the SJV, which we refer to collectively herein as the ``2012 
PM2.5 Plan and Supplement.'' \273\ On August 31, 2016, the 
EPA approved most elements of the 2012 PM2.5 Plan and 
Supplement into the California SIP.\274\ As part of this action, the 
EPA approved, among other things, commitments by the District to take 
specific actions with respect to identified control measures and to 
achieve specific amounts of direct PM2.5 emission reductions 
from these or substitute measures by 2017.\275\ The specific District 
commitments that the EPA approved into the California SIP as part of 
the 2012 PM2.5 Plan and Supplement are as follows:
---------------------------------------------------------------------------

    \273\ SJVUAPCD, ``2012 PM2.5 Plan,'' December 20, 
2012 (``2012 PM2.5 Plan'') and SJVUAPCD, ``Supplemental 
Document, Clean Air Act Subpart 4: The 2012 PM2.5 Plan 
for the 2006 PM2.5 Standard and District Rule 2201 (New 
and Modified Stationary Source Review),'' September 18, 2014 
(``Supplement'').
    \274\ 81 FR 59876 (August 31, 2016).
    \275\ 40 CFR 52.220(c)(478)(ii)(A)(3) and SJVUAPCD Governing 
Board Resolution 2012-12-19 (December 20, 2012). See also 81 FR 
59876, 59893, Table 5. CARB did not make any separate commitments in 
this SIP submission. CARB Resolution 13-2 (adopting the 2012 
PM2.5 Plan) and CARB Resolution 14-37 (adopting the 
Supplement).
---------------------------------------------------------------------------

    (1) A commitment by the District to ``adopt and implement the rules 
and measures in the Plan by the dates specified in Chapter 5'' of the 
2012 PM2.5 Plan and to submit these rules and measures to 
CARB within 30 days of adoption for transmittal to the EPA as SIP 
revisions; and
    (2) A commitment by the District to ``achieve the emission 
reductions shown in Chapter 5'' of the 2012 PM2.5 Plan, 
which are 1.9 tpd of direct PM2.5 by 2017, through the rules 
and measures identified in Chapter 5 of the 2012 PM2.5 Plan 
or through substitute measures.\276\
---------------------------------------------------------------------------

    \276\ Id.
---------------------------------------------------------------------------

    In Chapter 6, section 6.2 of the 2018 PM2.5 Plan 
(``Compliance with the Applicable SIP''), the District discusses its 
compliance with these rulemaking and emission reduction commitments as 
of October 16, 2018, when the Plan was made available for public 
review.
    Table 5 provides the current status of the District's compliance 
with its rulemaking commitments in the Moderate area plan for the 2006 
PM2.5 NAAQS. We note that although Table 5 includes specific 
projected emission reductions associated with two rules, Rule 4692 
(``Commercial Charbroiling'') and Rule 4901 (``Wood Burning Fireplaces 
and Wood Burning Heaters''), the District's emissions reduction 
commitment was an aggregate commitment that could be met through the 
identified measures or substitute measures.\277\
---------------------------------------------------------------------------

    \277\ 40 CFR 52.220(c)(478)(ii)(A)(3).

[[Page 17408]]



                  Table 5--EPA Review of the San Joaquin Valley 2012 PM2.5 Plan's Specific SJVUAPCD Commitments To Adopt or Amend Rules
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                            District Commitment                                      District Action
                                          --------------------------------------------------------------------------------------------------------------
           Rule Number (Title)              Amendment  Compliance
                                              year        year          Emission reductions         Amendment date                   Notes
--------------------------------------------------------------------------------------------------------------------------------------------------------
Rule 4308 (``Boilers, Steam Generators,          2013        2015  TBD                              November 14, 2013  EPA approval, 80 FR 7803
 and Process Heaters 0.075 to <2 MMBtu/                                                                                 (February 12, 2015).
 hr'').
Rule 4692 (``Commercial Charbroiling'')..        2016        2017  0.4 tpd direct PM2.5........         June 21, 2018  Submitted to the EPA November 21,
                                                                                                                        2018; Amended rule does not
                                                                                                                        establish control requirement
                                                                                                                        for under-fired commercial
                                                                                                                        charbroilers.
Rule 4901 (``Wood Burning Fireplaces and         2016   2016/2017  1.5 tpd direct PM2.5........    September 18, 2014  EPA approval, 81 FR 69393
 Wood Burning Heaters'').                                                                                               (October 6, 2016).
Rule 4905 (``Natural Gas-Fired, Fan-Type         2014        2015  TBD                               January 22, 2015  EPA approval, 81 FR 17390 (March
 Residential Central Furnaces'').                                                                                       29, 2016).
Rule 9610 (``SIP-creditability of                2013        2013  TBD                                  June 20, 2013  EPA limited approval and limited
 Incentives'').                                                                                                         disapproval, 80 FR 19020 (April
                                                                                                                        9, 2015).
--------------------------------------------------------------------------------------------------------------------------------------------------------
Source: 2012 PM2.5 Plan (for the 2006 PM2.5 NAAQS), Chapter 5, Table 5-3 (``Regulatory Control Measure Commitments'').

    In sum, the District has adopted and submitted to the EPA all five 
of the regulatory measures specified in Chapter 5 of the 2012 
PM2.5 Plan that it had committed to adopt and implement by 
specified dates. Based on our review of this information, we propose to 
find that the District has satisfied all of its rulemaking commitments 
in the 2012 PM2.5 Plan and Supplement.
    With respect to the District's aggregate tonnage commitment to 
achieve 1.9 tpd of direct PM2.5 by 2017, the District states 
that measures adopted after the State's adoption of the 2012 
PM2.5 Plan achieved emission reductions in excess of those 
committed to in the 2012 PM2.5 Plan and Supplement.\278\ 
Specifically, the District states that its commitment has been achieved 
through amendments to Rule 4901 (``Wood Burning Fireplaces and Wood 
Burning Heaters'').\279\ We have reviewed the District's and CARB's 
explanations of how the District fulfilled this commitment through 
implementation of revisions to its residential wood burning rule during 
the relevant time period.\280\
---------------------------------------------------------------------------

    \278\ 2018 PM2.5 Plan, Chapter 6, 6-3 to 6-4.
    \279\ Id. at 6-5 to 6-6.
    \280\ 2018 PM2.5 Plan, Table 6-2; email dated 
November 27, 2019, from Jon Klassen, SJVUAPCD, to Rory Mays, EPA 
Region IX, Subject: Emissions Reductions from 2014 Amendment to Rule 
4901; and letter dated February 4, 2020 from Kurt Karperos, CARB, to 
Elizabeth Adams, EPA Region IX.
---------------------------------------------------------------------------

    The District has amended Rule 4901 several times since its original 
adoption in 2003. As of the date the District adopted the 2012 
PM2.5 Plan, the October 16, 2008 amendment to Rule 4901 
applied and the District committed to further amend the rule. The 
District further amended the rule on September 18, 2014, and the 
amended rule took effect in the November 2014-February 2015 period. The 
District's staff report for the 2014 amendment to Rule 4901 projected 
that the amendment would achieve 24-hour winter-season average emission 
reductions by 2018 of 2.2 tpd of direct PM2.5.\281\ The EPA 
approved this rule into the SIP on October 6, 2016.\282\ In our final 
action, we noted that the District had projected that the rule revision 
would achieve 3.27 tpd of direct PM2.5 reductions during 
November through February (120-day) (equivalent to a winter-season 
average reduction of 2.2 tpd).\283\ This approval did not include an 
evaluation of whether the rule had achieved any particular level of 
emissions reductions, or whether the District had fulfilled its 
commitment to achieve 1.9 tpd of emissions reductions through revisions 
to Rule 4901.
---------------------------------------------------------------------------

    \281\ SJVUAPCD, ``Final Staff Report for Amendments to the 
District's Residential Wood Burning Program,'' September 18, 2014 
(``2014 Rule 4901 Staff Report''), App. B, B-12. We note that the 
2.2 tpd is based on a 180-day season that reflects the November 
through April (180-day) period used by the State for ``winter-
season,'' 24-hour average emissions inventories for the San Joaquin 
Valley. This District staff report estimates that the 2014 amendment 
would achieve emission reductions of 3.27 tpd of direct 
PM2.5 during the November through February (120-day) 
period in which it applies. See also 80 FR 58637, 58639 (September 
30, 2015) (proposed approval of 2014 amendment to Rule 4901) and 81 
FR 69393 (October 6, 2016) (final approval of 2014 amendment).
    \282\ 81 FR 69393.
    \283\ Id., at 69393-69394.
---------------------------------------------------------------------------

    We note that the 2018 PM2.5 Plan included updated 
emissions inventories for this source category.\284\ Consistent with 
CAA section 172(c)(3), which requires nonattainment plans to include 
inventories that are ``comprehensive, accurate, [and] current,'' 
attainment plans often include updated emission inventories that rely 
on information developed since an earlier plan. The 2018 
PM2.5 Plan's updated emission inventories for wood burning 
devices may be relevant to a determination of whether the 2014 
amendments to Rule 4901 resulted in 1.9 tpd of direct PM2.5 
emissions reductions by 2017. In particular, the 2018 PM2.5 
Plan's control measure analyses differ from previous inventory 
estimates in the following ways:
---------------------------------------------------------------------------

    \284\ Appendix B Table B-1 of the 2018 PM2.5 Plan 
contains a summary of direct PM2.5 emissions inventories 
from various source categories, including Residential Fuel 
Combustion, but does not include emissions values specific to wood-
burning devices. The emissions inventories for wood burning devices 
are found in Appendix C of the 2018 PM2.5 Plan, at C-257.
---------------------------------------------------------------------------

     The 2018 PM2.5 Plan inventories estimate that 
2013 winter season emissions from residential wood burning devices were 
6.35 tpd, compared with the 2015 winter season estimate of 8.037 tpd in 
the 2014 Rule 4901 Staff Report.\285\
---------------------------------------------------------------------------

    \285\ 2014 Rule 4901 Staff Report, App. B, B-5.
---------------------------------------------------------------------------

     The 2018 PM2.5 Plan inventories estimate that 
2017 winter season emissions from residential wood burning devices were 
5.49 tpd,

[[Page 17409]]

compared with the 2017 winter season inventory of 8.35 tpd estimated in 
the 2012 PM2.5 Plan and Supplement.
    Overall, the more recent inventories presented in the 2018 
PM2.5 Plan show a 0.86 tpd reduction in winter season direct 
PM2.5 emissions from wood burning devices between 2013 and 
2017.\286\ Similarly, the State's August 12, 2019 clarification to its 
2017 quantitative milestone report states that a 0.86 tpd reduction in 
these emissions occurred from 2013 to 2017.\287\
---------------------------------------------------------------------------

    \286\ 2018 PM2.5 Plan, App. C, C-257.
    \287\ Letter dated August 12, 2019, from Richard W. Corey, 
Executive Officer, CARB, to Mike Stoker, Regional Administrator, EPA 
Region IX, transmitting ``Attachment: Supplemental Information and 
Clarifications to 2017 Quantitative Milestones.''
---------------------------------------------------------------------------

    This difference between the emission reductions projected in the 
2014 Rule 4901 Staff Report and the emission reductions reflected in 
the inventories in Appendix C of the 2018 PM2.5 Plan appears 
to be due to an update to emissions inventory methods in 2015-2016. The 
updated methodology indicates that emissions from this source category 
are lower than emissions as calculated by the methodology used to 
develop the emissions inventory in the 2012 PM2.5 Plan.\288\ 
The updated methodology is based on a 2014 survey of San Joaquin Valley 
residents, which provided more representative data regarding fuel usage 
rates and the number of wood burning devices in use in the 
District.\289\
---------------------------------------------------------------------------

    \288\ SJVUAPCD, ``2015 Area Source Emissions Inventory 
Methodology 610--Residential Wood Combustion,'' (dated October 18, 
2016), 27, Table 12 (showing decrease in estimated 2015 annual 
emissions from woodstoves and fireplaces of 461 tons per year).
    \289\ Id. at 22.
---------------------------------------------------------------------------

    In light of this difference between the emission reductions 
projected in the 2014 Rule 4901 Staff Report and the emission 
reductions reflected in the inventories in Appendix C of the 2018 
PM2.5 Plan, the EPA sought clarification from CARB and the 
District regarding the reductions achieved by the 2014 rule amendment. 
In response, CARB pointed to the analysis of emissions reductions in 
the 2014 Rule 4901 Staff Report as demonstrating compliance with the 
commitment to achieve 1.9 tpd of emissions reductions.\290\ CARB and 
the District also noted that the 2012 PM2.5 Plan projected 
that 2017 emissions from wood burning devices would be 8.35 tpd and the 
2018 PM2.5 Plan inventory estimates that 2017 emissions from 
wood burning devices were 5.49 tpd, and concluded that this comparison 
reflects emission reductions of 2.86 tpd for this source category.\291\
---------------------------------------------------------------------------

    \290\ Email dated November 27, 2019, from Jon Klassen, SJVUAPCD, 
to Rory Mays, EPA Region IX, Subject: Emissions Reductions from 2014 
Amendment to Rule 4901; Letter dated February 4, 2020 from Kurt 
Karperos, CARB, to Elizabeth Adams, EPA Region IX, 2-3.
    \291\ Id.
---------------------------------------------------------------------------

    We propose to find, based upon the analysis of projected emission 
reductions in the 2014 Rule 4901 Staff Report, that the District has 
complied with the aggregate commitment in the 2012 PM2.5 
Plan to achieve total emission reductions of 1.9 tpd of direct 
PM2.5 by 2017. Given the differences between the inventories 
used to create the commitment and the current inventories, we also seek 
comment as to whether the State and District have met the commitment to 
achieve total emission reductions of 1.9 tpd of direct PM2.5 
by 2017.
3. Demonstration That the Implementation Plan Includes the Most 
Stringent Measures
    We interpret this criterion to mean that the State must demonstrate 
to the EPA's satisfaction that its Serious area plan includes the most 
stringent measures that are included in the implementation plan of any 
state, or achieved in practice in any state, and can feasibly be 
implemented in the area.
    As discussed in section IV.C of this preamble, because of the 
substantial overlap in the source categories and controls evaluated for 
BACM and those evaluated for MSM, we present our evaluation of the 2018 
PM2.5 Plan's provisions for including MSM alongside our 
evaluation of the Plan's provisions for implementing BACM for each 
identified source category. For the reasons provided in section IV.C 
and further in the EPA's BACM/MSM TSD, we propose to determine that the 
SJV PM2.5 Plan provides for the implementation of MSM for 
sources of direct PM2.5 and PM2.5 plan precursors 
as expeditiously as practicable and no later than January 1, 2024, in 
accordance with the requirements of CAA section 188(e) and the 
PM2.5 SIP Requirements Rule.
4. Demonstration of Attainment by the Most Expeditious Alternative Date 
Practicable
    Section 189(b)(1)(A) of the CAA requires that each Serious area 
plan include a demonstration (including air quality modeling) that the 
plan provides for attainment of the PM2.5 NAAQS by the 
applicable attainment date or, where the State is seeking an extension 
of the attainment date under section 188(e), a demonstration that 
attainment by that date is impracticable and that the plan provides for 
attainment by the most expeditious alternative date practicable. We 
discuss below our evaluation of the modeling approach in the Plan, the 
State's basis for excluding one 24-hour data point from the modeling 
analysis, and the control strategy in the Plan for attaining the 2006 
24-hour PM2.5 NAAQS by the most expeditious alternative date 
practicable.
a. Air Quality Modeling Approach and Results
    The EPA's recommended procedures for modeling ambient 
PM2.5 as part of an attainment demonstration are contained 
in the EPA's ``Modeling Guidance for Demonstrating Attainment of Air 
Quality Goals for Ozone, PM2.5, and Regional Haze'' 
(``Modeling Guidance'').\292\ This guidance recommends that a state use 
a photochemical model, such as the Comprehensive Air-quality Model with 
extensions (CAMx) or CMAQ, to simulate a base case, with meteorological 
and emissions inputs reflecting a base case year, to replicate 
concentrations monitored in that year. The model application to the 
base case year undergoes a performance evaluation to ensure that it 
corroborates concentrations monitored in that year. States may then use 
the model to simulate emissions occurring in other years required for 
an attainment plan, namely the base year (which may differ from the 
base case year) and a future year. The modeled response to the emission 
changes between those years is used to calculate Relative Response 
Factors (RRFs), which are applied to the design value in the base year 
to estimate the projected design value in the future year for 
comparison against the NAAQS. Separate RRFs are estimated for each 
chemical species component of PM2.5, and for each quarter of 
the year, to reflect their differing responses to seasonal 
meteorological conditions and emissions. Since each species is handled 
separately, before applying an RRF the base year design value must be 
speciated using available chemical species measurements, that is, each

[[Page 17410]]

day's measured PM2.5 comprising the design value must be 
split into its species components. The Modeling Guidance provides 
additional detail on the recommended approach.
---------------------------------------------------------------------------

    \292\ ``Modeling Guidance for Demonstrating Air Quality Goals 
for Ozone, PM2.5, and Regional Haze,'' EPA-454/R-18-009, 
November 2018; available at: https://www.epa.gov/scram/state-implementation-plan-sip-attainment-demonstration-guidance. During 
development of the SJV PM2.5 Plan, CARB relied on the 
draft version of this guidance update, ``Draft Modeling Guidance for 
Demonstrating Attainment of Air Quality Goals for Ozone, 
PM2.5, and Regional Haze,'' OAQPS, EPA, December 3, 2014 
Draft,; 2018 PM2.5 Plan, App. K, 11. Additional EPA 
modeling guidance can be found in 40 CFR 51 App. W (``Guideline on 
Air Quality Models''), 82 FR 5182 (January 17, 2017); available at 
https://www.epa.gov/scram/clean-air-act-permit-modeling-guidance.
---------------------------------------------------------------------------

    The 2018 PM2.5 Plan includes a modeled demonstration 
projecting that the San Joaquin Valley will attain the 2006 24-hour 
PM2.5 NAAQS by December 31, 2024. Specifically, CARB 
conducted photochemical modeling with the CMAQ model using inputs 
developed from routinely available meteorological and air quality data, 
as well as more detailed and extensive data from the DISCOVER-AQ field 
study conducted in January to February 2013.\293\
---------------------------------------------------------------------------

    \293\ NASA, ``Deriving Information on Surface conditions from 
COlumn and VERtically Resolved Observations Relevant to Air 
Quality,'' available at https://www.nasa.gov/mission_pages/discover-aq/index.html.
---------------------------------------------------------------------------

    The Plan's primary discussion of the photochemical modeling appears 
in Appendix K (``Modeling Attainment Demonstration'') of the 2018 
PM2.5 Plan. The State briefly summarizes the area's air 
quality problem in Chapter 2.2 (``Air Quality Challenges And Trends'') 
and summarizes the modeling results in Chapter 6.4 (``Attainment 
Demonstration and Modeling'') of the 2018 PM2.5 Plan. The 
State provides a conceptual model of PM2.5 formation in the 
San Joaquin Valley as part of the modeling protocol in Appendix L 
(``Modeling Protocol''). Appendix J (``Modeling Emission Inventory'') 
describes emission input preparation procedures. The State presents 
additional relevant information in Appendix C (``Weight of Evidence 
Analysis'') of the CARB Staff Report, which includes ambient trends and 
other data in support of the attainment demonstration.
    CARB's air quality modeling approach investigated the many inter-
connected facets of modeling ambient PM2.5 in the San 
Joaquin Valley, including model input preparation, model performance 
evaluation, use of the model output for the numerical NAAQS attainment 
test, and modeling documentation. Specifically, this required the 
development and evaluation of a conceptual model, modeling protocol, 
episode (i.e., base year) selection, modeling domain, CMAQ model 
selection, initial and boundary condition procedures, meteorological 
model choice and performance, modeling emissions inventory preparation 
procedures, model performance, attainment test procedure, adjustments 
to baseline air quality for modeling, the 2024 attainment test, and an 
unmonitored area analysis. CARB's supplemental weight of evidence 
analysis further supports the Plan's demonstration of attainment by the 
end of 2024. These analyses are generally consistent with the EPA's 
recommendations in the Modeling Guidance.
    The model performance evaluation in Appendix K included statistical 
and graphical measures of model performance. The magnitude and timing 
of predicted concentrations of total PM2.5, as well as of 
its ammonium and nitrate components, generally match the occurrence of 
elevated PM2.5 levels in the measured observations. A 
comparison to other recent modeling efforts shows good model 
performance on bias, error, and correlation with measurements, for 
total PM2.5 and for most of its chemical components. The 
Weight of Evidence Analysis\294\ shows the downward trend in 
NOX emissions along with a 50% decrease between 1999 and 
2017 in the number of days above the 2006 PM2.5 NAAQS.\295\ 
The analysis also shows decreases in daily PM2.5 
concentrations during winter, and in the frequency of high 
PM2.5 concentrations generally. Available ambient air 
quality data shows that total PM2.5 and ammonium nitrate 
concentrations have clearly declined over the 2001-2015 period, despite 
some increases from time to time.\296\ These air quality trends show 
that there has been a substantial improvement in air quality due to 
emission reductions in the SJV, although that point is not fully 
reflected in the 98th percentile statistic, which is the basis for the 
regulatory design value.\297\ These lines of evidence all lend 
confidence in the modeling and the attainment demonstration.
---------------------------------------------------------------------------

    \294\ CARB Staff Report, Appendix C.
    \295\ Id. at 28.
    \296\ An increase in 2013 and 2014 is attributed to severe 
drought-related conditions during the winter of 2013-2014. Id. at 
27.
    \297\ Letter dated May 9, 2019, from Richard Corey, Executive 
Officer, CARB, to Mike Stoker, Regional Administrator, EPA Region 9 
(transmitting SJV PM2.5 Plan to EPA), Attachment A, 3.
---------------------------------------------------------------------------

    Given the State's extensive discussion of modeling procedures, 
tests, and performance analyses in the Modeling Protocol, and the good 
model performance, the EPA finds that the modeling in the SJV 
PM2.5 Plan is adequate for purposes of supporting the 
demonstration of attainment by 2024. For further detail, please see the 
EPA's Modeling TSD.
b. Control Strategy
    The SJV PM2.5 Plan's control strategy to reduce 
emissions from sources of NOX and direct PM2.5 is 
presented in Chapter 4 (``Attainment Strategy for PM2.5'') 
\298\ and related supporting information in the Plan's control strategy 
appendices, including Appendix C (``Stationary Source Control Measure 
Analyses''), Appendix D (``Mobile Source Control Measures Analyses''), 
and Appendix E (``Incentive-Based Strategy''). Most of the projected 
emission reductions are achieved by baseline measures--i.e., the 
combination of State and District measures adopted prior to the State's 
and District's adoption of the Plan--that will achieve ongoing emission 
reductions from the 2013 base year to the 2024 projected attainment 
year.
---------------------------------------------------------------------------

    \298\ Consistent with the State and District's determination 
that ammonia, SOX, and VOC do not contribute 
significantly to PM2.5 levels exceeding the NAAQS in the 
San Joaquin Valley, the Plan's control strategy focuses on 
reductions in emissions of direct PM2.5 and 
NOX. CARB Staff Report, 12. Nonetheless, the Plan 
projects the following annual average emission reductions from the 
2013 base year to 2024: 0.5 tpd reductions in SOX (5.9%), 
30.3 tpd reductions in VOC (9.3%), and 4.6 tpd reductions in ammonia 
(1.4%). 2018 PM2.5 Plan, App. B, Tables B-3, B-4, and B-
5.
---------------------------------------------------------------------------

    The remainder of the emission reductions are achieved by an 
incentive-based measure adopted by CARB in December 2019, a regulatory 
measures adopted by the District in June 2019, and a number of 
additional measures to be adopted and implemented by CARB and the 
District, including regulatory measures and incentive-based measures. 
In addition, both the 2018 PM2.5 Plan and the Valley State 
SIP Strategy include commitments to take action on specific measures by 
specific dates and to achieve specified amounts of NOX and 
PM2.5 emission reductions by certain dates.\299\ We refer to 
these commitments herein as ``aggregate commitments.''
---------------------------------------------------------------------------

    \299\ CARB Resolution 18-49, paragraph 2 and SJVUAPCD Governing 
Board Resolution 18-11-16, paragraph 6.
---------------------------------------------------------------------------

    We note that the SJV PM2.5 Plan generally relies on 
annual average emission inventory and control strategy estimates 
because it was designed to address requirements for the 1997 annual and 
24-hour PM2.5 NAAQS, the 2006 24-hour PM2.5 
NAAQS, and the 2012 annual PM2.5 NAAQS. The State views the 
control strategy for the annual average attainment needs as providing 
sufficient emission reductions for 24-hour average (winter average) 
attainment and RFP needs.\300\ We agree with this assessment and have 
evaluated the control strategy in the Plan by reference to annual 
average emission reductions. Table 6 provides a summary

[[Page 17411]]

of the 2013 base year emissions and the reductions from baseline 
measures, additional State measures, and additional District measures 
that are necessary for the San Joaquin Valley to attain the 2006 
PM2.5 NAAQS by December 31, 2024.\301\
---------------------------------------------------------------------------

    \300\ See, e.g., Letter dated August 12, 2019 from Richard 
Corey, Executive Officer, CARB to Mike Stoker, Regional 
Administrator, EPA Region IX, regarding the State's ``2017 
Quantitative Milestone Report for the 1997 and 2006 NAAQS,'' 2, n. 
3.
    \301\ Emission reductions from baseline measures are calculated 
as the sum of all stationary, area, and mobile source emission 
reductions from 2013 to 2024 in App. B of the 2018 PM2.5 
Plan.

               Table 6--Summary of SJV PM2.5 Plan's Annual Average Emission Reductions to Attain the 2006 PM2.5 NAAQS by December 31, 2024
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                                            % of 2013-
                                                                                                          % of 2013 base   Direct PM2.5      base year
                                                                                             NOX (tpd)    year emissions       (tpd)         emissions
                                                                                                             (percent)                       (percent)
--------------------------------------------------------------------------------------------------------------------------------------------------------
A..............................................  2013 Base Year Emissions...............           317.2  ..............            62.5  ..............
B..............................................  Baseline Measure Emission Reductions              168.3            53.1             4.2             6.7
                                                  (2013-2024).
C..............................................  Additional State Measures..............              32            10.1             0.9             1.4
D..............................................  Additional District Measures...........            1.88             0.6             1.3             2.1
E..............................................  Total 2013-2024 Emission Reductions               202.2            63.7             6.4            10.2
                                                  (B+C+D).
--------------------------------------------------------------------------------------------------------------------------------------------------------
Source: 2018 PM2.5 Plan, Appendix B, Tables B-1 and B-2, and Ch. 4, Tables 4-3 and 4-7.

i. Baseline Measures
    Baseline measures will provide the majority of emissions reductions 
needed to attain the 2006 24-hour PM2.5 NAAQS in the San 
Joaquin Valley, amounting to approximately 83.2% of the NOX 
emission reductions and 65.6% of the direct PM2.5 emission 
reductions necessary for attainment.\302\
---------------------------------------------------------------------------

    \302\ The EPA calculated these percentages as follows: Annual 
average baseline NOX reductions are 168.3 tpd of 202.2 
tpd necessary for attainment (83.2%) and annual average baseline 
direct PM2.5 reductions are 4.2 tpd of 6.4 tpd necessary 
for attainment (65.6%). 2018 PM2.5 Plan, Ch. 4 and App. 
B.
---------------------------------------------------------------------------

    The 2018 PM2.5 Plan states that mobile sources emit over 
85% of the NOX in the San Joaquin Valley and that CARB has 
adopted and amended regulations to reduce public exposure to diesel 
particulate matter, which includes direct PM2.5, and 
NOX, from ``fuel sources, freight transport sources like 
heavy-duty diesel trucks, transportation sources like passenger cars 
and buses, and non-road sources like large construction equipment.'' 
\303\
---------------------------------------------------------------------------

    \303\ 2018 PM2.5 Plan, Ch. 4, 4-9 and Valley State 
SIP Strategy, 4. For CARB's analysis of its mobile source measures 
for BACM and MSM, see 2018 PM2.5 Plan, App. D, including 
analyses for on-road light-duty vehicles and fuels (starting page D-
17), on-road heavy-duty vehicles and fuels (starting page D-35), and 
non-road sources (starting page D-64).
---------------------------------------------------------------------------

    Given the need for substantial emissions reductions from mobile and 
area sources to meet the NAAQS in California nonattainment areas, the 
State of California has developed stringent control measures for on-
road and non-road mobile sources and the fuels that power them. 
California has unique authority under CAA section 209 (subject to a 
waiver by the EPA) to adopt and implement new emissions standards for 
many categories of on-road vehicles and engines and new and in-use non-
road vehicles and engines. The EPA has approved such mobile source 
regulations for which waiver authorizations have been issued as 
revisions to the California SIP.\304\
---------------------------------------------------------------------------

    \304\ See e.g., 81 FR 39424 (June 16, 2016); 82 FR 14447 (March 
21, 2017); and 83 FR 23232 (May 18, 2018).
---------------------------------------------------------------------------

    CARB's mobile source program extends beyond regulations that are 
subject to the waiver or authorization process set forth in CAA section 
209 to include standards and other requirements to control emissions 
from in-use heavy-duty trucks and buses, gasoline and diesel fuel 
specifications, and many other types of mobile sources. Generally, 
these regulations have also been submitted and approved as revisions to 
the California SIP.\305\
---------------------------------------------------------------------------

    \305\ See e.g., the EPA's approval of standards and other 
requirements to control emissions from in-use heavy-duty diesel 
trucks, 77 FR 20308 (April 4, 2012), and revisions to the California 
on-road reformulated gasoline and diesel fuel regulations, 75 FR 
26653 (May 12, 2010).
---------------------------------------------------------------------------

    As to stationary sources, the 2018 PM2.5 Plan states 
that stringent regulations adopted for prior attainment plans continue 
to reduce emissions of NOX and direct PM2.5.\306\ 
Specifically, Table 4-1 of the 2018 PM2.5 Plan (``District 
Rules Reducing PM and NOX Emissions in the Valley'') 
identifies 33 District measures that limit NOX and direct 
PM2.5 emissions.\307\ The EPA has approved each of the 
identified measures into the California SIP,\308\ with four exceptions.
---------------------------------------------------------------------------

    \306\ 2018 PM2.5 Plan, Ch. 4, 4-3. For the District's 
analysis of its stationary source measures for BACM and MSM, see 
2018 PM2.5 Plan, App. C.
    \307\ Id. Ch. 4, Table 4-1.
    \308\ See EPA Region IX's website for information on District 
control measures that have been approved into the California SIP, 
available at: https://www.epa.gov/sips-ca/epa-approved-san-joaquin-valley-unified-air-district-regulations-california-sip.
---------------------------------------------------------------------------

    First, the District amended Rule 4692 (``Commercial Charbroiling'') 
on June 21, 2018, to establish new registration and reporting 
requirements for certain types of charbroiling operations. These 
amendments to Rule 4692 require commercial cooking operations with UFCs 
to report by January 1, 2019, on the type and quantity, in pounds, of 
meat cooked on the UFCs on a weekly basis for the previous 12-month 
period as well as other information regarding the nature of their 
operations, and for certain such operations to register with the 
District and keep weekly records relating to the quantities of meat 
cooked.\309\ CARB submitted the amended rule to the EPA on November 21, 
2018, and the EPA has not yet proposed any action on this submission. 
The EPA approved a prior version of this rule into the SIP on November 
3, 2011.\310\ The District states that the 2018 amendment was an 
important first step in its ongoing process to develop a new control 
measure that will include financial incentives to help fund accelerated 
deployment of under-fired charbroiler emission control 
technologies.\311\ The 2018 amendments do not, however, establish any 
new control requirements and therefore do not achieve additional 
emission reductions beyond those that continue to be achieved by the 
SIP-approved version of Rule 4692.
---------------------------------------------------------------------------

    \309\ SJVUAPCD Rule 4692, as amended June 21, 2018, and 
SJVUAPCD, Final Draft Staff Report, ``Amendments to Rule 4692 
(Commercial Charbroiling),'' June 21, 2018, 1 and 5-6.
    \310\ 76 FR 68103 (November 3, 2011) (approving Rule 4692 as 
amended September 17, 2009).
    \311\ SJVUAPCD, Final Draft Staff Report, ``Amendments to Rule 
4692 (Commercial Charbroiling),'' June 21, 2018, 1.
---------------------------------------------------------------------------

    Second, the District amended Rule 4905 (``Natural Gas-fired, Fan-
type, Residential Central Furnaces'') on June 21, 2018, to extend the 
period during which manufacturers may pay emission fees in lieu of 
meeting the rule's NOX

[[Page 17412]]

emission limits.\312\ CARB submitted the amended rule to the EPA on 
November 21, 2018, and the EPA has not yet proposed any action on this 
submission. The EPA approved a prior version of Rule 4905 into the 
California SIP on March 29, 2016.\313\ As part of that rulemaking, the 
EPA noted that because of the option in Rule 4905 to pay mitigation 
fees in lieu of compliance with emission limits, emission reductions 
associated with the rule's emission limits would not be creditable in 
any attainment plan without additional documentation.\314\ Until the 
District submits the necessary documentation to credit emission 
reductions achieved by Rule 4905 toward an attainment control strategy, 
this rule is not creditable for SIP purposes. The 2018 PM2.5 
Plan indicates that the District attributed 0.26 tpd of NOX 
reductions between 2013 and 2024 to Rule 4905.\315\ These emission 
reductions have de minimis impacts on the attainment demonstration in 
the SJV PM2.5 Plan.
---------------------------------------------------------------------------

    \312\ SJVUAPCD, Final Draft Staff Report, ``Proposed Amendments 
to Rule 4905 (Natural Gas-fired, Fan-type Central Furnaces),'' 2.
    \313\ 81 FR 17390 (March 29, 2016) (approving Rule 4905 as 
amended January 22, 2015).
    \314\ EPA, Region IX Air Division, ``Technical Support Document 
for EPA's Proposed Rulemaking for the California State 
Implementation Plan (SIP), San Joaquin Valley Unified Air Pollution 
Control District's Rule 4905, Natural Gas-Fired, Fan-Type Central 
Furnaces,'' October 5, 2015, n. 8.
    \315\ 2018 PM2.5 Plan, App. C, C-290.
---------------------------------------------------------------------------

    Third, the District amended Rule 9510 (``Indirect Source Review'') 
on December 21, 2017, to eliminate inconsistencies in its applicability 
provisions and to ensure that all large development projects are 
subject to the rule.\316\ CARB submitted this rule to the EPA on May 
23, 2018, and the EPA has not yet proposed any action on the 
submission. The EPA approved a prior version of this rule into the 
California SIP on May 9, 2011.\317\ As part of that rulemaking, the EPA 
noted that emission reductions associated with this rule would not be 
creditable in any attainment or RFP demonstration unless the District 
revises the rule to address the EPA's enforceability concerns.\318\ 
Until the District adopts such revisions to the rule, Rule 9510 is not 
creditable for SIP purposes. The 2018 PM2.5 Plan does not, 
however, appear to rely on this rule to any measurable extent in the 
projected attainment inventory.\319\ Therefore, the District's 
inclusion of this rule in Table 4-1 of the 2018 PM2.5 Plan 
has no impact on our evaluation of the attainment demonstration.
---------------------------------------------------------------------------

    \316\ SJVUAPCD, Final Draft Staff Report, ``Rule 9510 Indirect 
Source Review.'' December 21, 2017, 1.
    \317\ 76 FR 26609 (May 9, 2011) (approving Rule 9510 as amended 
December 15, 2005).
    \318\ 76 FR 26609, 26612-26614.
    \319\ The District's control analysis states that there is no 
emissions inventory specific to Rule 9510. 2018 PM2.5 
Plan, App. C, C-302.
---------------------------------------------------------------------------

    Finally, the 2018 PM2.5 Plan lists Rule 4203 
(``Particulate Matter Emissions from Incineration of Combustible 
Refuse'') as a baseline measure. This rule has not been approved into 
the California SIP.\320\ Appendix C of the 2018 PM2.5 Plan 
states, however, that the emissions inventory for incineration of 
combustible refuse is 0.00 tpd of NOX and 0.00 direct 
PM2.5 from 2013 through 2024.\321\ Thus, to the extent the 
District relied upon emission reductions achieved by this rule in its 
future baseline emissions estimates, those emission reductions have de 
minimis impacts on the attainment demonstration in the SJV 
PM2.5 Plan.
---------------------------------------------------------------------------

    \320\ The EPA does not have any pending SIP submission for Rule 
4203.
    \321\ 2018 PM2.5 Plan, App. C, C-46.
---------------------------------------------------------------------------

    In sum, although Table 4-1 of the 2018 PM2.5 Plan 
identifies four baseline measures that are not creditable for SIP 
purposes at this time, we find that the total emission reductions 
attributed to these four measures in the future baseline inventories 
have de minimis impacts on the attainment demonstration in the Plan.
ii. Additional Measures and Aggregate Commitments
    The SJV PM2.5 Plan relies on an incentive-based measure 
recently adopted by CARB to achieve 5.9 tpd of NOX 
reductions and 0.3 tpd of direct PM2.5 reductions--2.9% and 
4.7%, respectively, of the total NOX and direct 
PM2.5 emission reductions necessary for the San Joaquin 
Valley to attain the 2006 PM2.5 NAAQS by December 31, 
2024.\322\ Under longstanding guidance, the EPA has recommended 
presumptive limits on the amounts of emission reductions from certain 
voluntary and other nontraditional measures that may be credited in a 
SIP. Specifically, for voluntary mobile source emission reduction 
programs, the EPA has identified a presumptive limit of three percent 
(3%) of the total projected future year emission reductions required to 
attain the appropriate NAAQS, and for any particular SIP submittal to 
demonstrate attainment or maintenance of the NAAQS or progress toward 
attainment (RFP), 3% of the specific statutory requirement.\323\ The 
EPA may, however, approve measures for SIP credit in amounts exceeding 
the presumptive limits where a clear and convincing justification is 
made by the State as to why a higher limit should apply in its 
case.\324\
---------------------------------------------------------------------------

    \322\ The 2018 PM2.5 Plan shows that 202.2 tpd of 
NOX and 6.4 tpd of PM2.5 emission reductions 
are necessary for San Joaquin Valley to attain the 2006 
PM2.5 NAAQS by December 31, 2024. 2018 PM2.5 
Plan, revised App. H, Table H-6. For further discussion of Appendix 
H, see section IV.E of this preamble.
    \323\ EPA, ``Guidance on Incorporating Voluntary Mobile Source 
Emission Reduction Programs in State Implementation Plans (SIPs),'' 
October 24, 1997, 5.
    \324\ EPA, ``Incorporating Emerging and Voluntary Measure in a 
State Implementation Plan (SIP),'' October 4, 2004, 9; see also EPA, 
``Guidance on Incorporating Bundled Measures in a State 
Implementation Plan,'' August 16, 2005, 8, n. 6, and EPA, ``Diesel 
Retrofits: Quantifying and Using Their Emission Benefits in SIPs and 
Conformity: Guidance for State and Local Air and Transportation 
Agencies,'' March 2018, 12.
---------------------------------------------------------------------------

    The San Joaquin Valley's topography and meteorology present 
significant challenges for air quality. As stated in the 2018 
PM2.5 Plan, ``the surrounding mountains trap pollution and 
block airflow'' and ``[t]emperature inversions, while present to some 
degree throughout the year, can last for days during the winter, 
holding in nighttime accumulations of pollutants.'' \325\ In addition, 
the population of the area continues to grow at a rate higher than the 
statewide growth rate, leading to increased vehicular traffic along 
major highways that run through the San Joaquin Valley.\326\ Given 
these unique challenges, both the State and District continue to 
implement both traditional and non-traditional emission reduction 
strategies to attain the PM2.5 standards in the San Joaquin 
Valley, including regulatory programs, incentive programs, and rigorous 
outreach and education efforts.\327\ Over the past several decades, the 
State and District have developed and implemented several comprehensive 
plans to address attainment of the NAAQS for ozone and particulate 
matter.\328\ These attainment plans have resulted in the State's and 
District's adoption of numerous regulations for stationary, area, and 
mobile sources, many of which are among the most stringent control 
measures in the nation. Given the air quality needs of the area and the 
numerous control measures that both the State and District have adopted 
and

[[Page 17413]]

implemented in the San Joaquin Valley to date, we believe it is 
appropriate to allow the State to rely on the Valley Incentive Measure 
to achieve 2.9% (5.9 tpd) of the NOX reductions and 4.7% 
(0.3 tpd) of the direct PM2.5 reductions necessary for the 
area to attain the 2006 PM2.5 NAAQS by the end of 2024.
---------------------------------------------------------------------------

    \325\ 2018 PM2.5 Plan, Ch. 2, 2-1.
    \326\ Id. at 2-4.
    \327\ Id. at 2-2.
    \328\ See, e.g., 69 FR 30005 (May 26, 2004) (approving plan to 
attain the 1987 PM10 NAAQS), 76 FR 69896 (November 9, 
2011) (partially approving and partially disapproving plan to attain 
the 1997 PM2.5 NAAQS), 77 FR 12652 (March 1, 2012) 
(approving plan to attain the 1997 8-hour ozone NAAQS), and 81 FR 
19492 (April 5, 2016) (approving plan to attain the 1979 1-hour 
ozone NAAQS).
---------------------------------------------------------------------------

    For the remainder of the emission reductions necessary for 
attainment, the SJV PM2.5 Plan identifies a series of 
additional State and District commitments to achieve emission 
reductions through additional control measures beyond baseline measures 
that will contribute to expeditious attainment of the 2006 
PM2.5 NAAQS. For mobile sources, CARB's commitment 
identifies a list of 12 State regulatory measures and three incentive-
based measures that CARB has committed to propose to its Board for 
consideration by specific dates.\329\ For stationary sources, the 
District's commitment identifies a list of nine regulatory measures and 
three incentive-based measures that the District has committed to 
propose to its Board for consideration by specific dates.\330\ The Plan 
contains CARB's and the District's estimates of the emission reductions 
that would be achieved by each of these additional measures, if 
adopted.\331\
---------------------------------------------------------------------------

    \329\ CARB Resolution 18-49 (October 25, 2018), Attachment A and 
Valley State SIP Strategy, Table 7 (``State Measures and Schedule 
for the San Joaquin Valley''). The EPA is excluding two State 
measures listed in Table 7 of the Valley State SIP Strategy--the 
``Advanced Clean Cars 2'' measure and the ``Cleaner In-Use 
Agricultural Equipment'' measure--because these measures are 
scheduled for implementation in 2026 and 2030, respectively, well 
after the January 1, 2024 implementation deadline for control 
measures necessary for attainment by December 31, 2024. 40 CFR 
51.1011(b)(5).
    \330\ SJVUAPCD Governing Board Resolution 18-11-16 (November 15, 
2018) and 2018 PM2.5 Plan, Table 4-4 (``Proposed 
Regulatory Measures'') and Table 4-5 (``Proposed Incentive-Based 
Measures'').
    \331\ 2018 PM2.5 Plan, Ch. 4, Table 4-3 (''Emission 
Reductions from District Measures'') and Table 4-9 (''San Joaquin 
Valley Expected Emission Reductions from State Measures'') and 
Valley State SIP Strategy, Table 8 (``San Joaquin Valley Expected 
Emission Reductions from State Measures'').
---------------------------------------------------------------------------

    CARB's commitments are contained in CARB Resolution 18-49 (October 
25, 2018) and the Valley State SIP Strategy and consist of two parts: A 
control measure commitment and a tonnage commitment. First, CARB has 
committed to ``begin the measure's public process and bring to the 
Board for consideration the list of proposed SIP measures outlined in 
the Valley State SIP Strategy and included in Attachment A, according 
to the schedule set forth.'' \332\ By email dated November 12, 2019, 
CARB confirmed that it intended to begin the public process on each 
measure by discussing the proposed regulation or program at a public 
meeting (workshop, working group, or Board hearing) or in a publicly-
released document and to then propose the regulation or program to its 
Board.\333\ Second, CARB has committed ``to achieve the aggregate 
emissions reductions outlined in the Valley State SIP Strategy of 32 
tpd of NOX and 0.9 tpd of PM2.5 emissions 
reductions in the San Joaquin Valley by 2024.'' \334\ The Valley State 
SIP Strategy explains that CARB's overall commitment is to ``achieve 
the total emission reductions necessary to attain the federal air 
quality standards, reflecting the combined reductions from the existing 
control strategy and new measures'' and that ``if a particular measure 
does not get its expected emissions reductions, the State is still 
committed to achieving the total aggregate emission reductions.'' \335\
---------------------------------------------------------------------------

    \332\ CARB Resolution 18-49 (October 25, 2018), 5.
    \333\ Email dated November 12, 2019, from Sylvia Vanderspek, 
CARB to Anita Lee, EPA Region IX, ``RE: SJV PM2.5 
information'' (attaching ``Valley State SIP Strategy Progress'') and 
CARB Staff Report, 14.
    \334\ CARB Resolution 18-49 (October 25, 2018), 5.
    \335\ Valley State SIP Strategy, 7.
---------------------------------------------------------------------------

    The District's commitments are contained in SJVUAPCD Governing 
Board Resolution 18-11-16 (November 15, 2018) and Chapter 4 of the 2018 
PM2.5 Plan and similarly consist of two parts: A control 
measure commitment and a tonnage commitment. First, the District has 
committed to ``take action on the rules and measures committed to in 
Chapter 4 of the Plan by the dates specified therein, and to submit 
these rules and measures, as appropriate, to CARB within 30 days of 
adoption for transmittal to EPA as a revision to the [SIP].'' \336\ By 
email dated November 12, 2019, the District confirmed that it intended 
to take action on the listed rules and measures by beginning the public 
process on each measure, i.e., discussing the proposed regulation or 
program at a public meeting, including a workshop, working group, or 
Board hearing, or in a publicly-released document, and then proposing 
the rule or measure to the SJVUAPCD Governing Board.\337\ Second, the 
District has committed to ``achieve the aggregate emissions reductions 
of 1.88 tpd of NOX and 1.3 tpd of PM2.5 by 2024/
2025'' through adoption and implementation of these measures or, if the 
total emission reductions from these rules or measures are less than 
these amounts, ``to adopt, submit, and implement substitute rules and 
measures that achieve equivalent reductions in emissions of direct 
PM2.5 or PM2.5 precursors'' in the same 
implementation timeframes.\338\
---------------------------------------------------------------------------

    \336\ SJVUAPCD Governing Board Resolution 18-11-16 (November 15, 
2018), 10-11.
    \337\ Email dated November 12, 2019, from Jon Klassen, SJVUAPCD 
to Wienke Tax, EPA Region IX, ``RE: follow up on aggregate 
commitments in SJV PM2.5 plan'' (attaching ``District 
Progress In Implementing Commitments with 2018 PM2.5 
Plan'').
    \338\ SJVUAPCD Governing Board Resolution 18-11-16 (November 15, 
2018), 10-11.
---------------------------------------------------------------------------

    In November 2019, CARB provided status updates on its progress to 
date on developing and adopting the additional mobile source measures 
identified in its control measure commitment.\339\ Table 7 lists each 
measure and provides a summary of the anticipated emission reductions 
and the current status for each measure. As shown in the ``Current 
Status'' column, CARB has adopted five measures and begun the public 
process on seven of the remaining 10 measures listed in its control 
measure commitment.
---------------------------------------------------------------------------

    \339\ Email dated November 12, 2019, from Sylvia Vanderspek, 
CARB to Anita Lee, EPA Region IX, ``RE: SJV PM2.5 
information'' (attaching ``Valley State SIP Strategy Progress'').

                             Table 7--Status of CARB Compliance With Control Measure Commitments for the San Joaquin Valley
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                          Direct PM2.5
                                                                                                         NOX emission       emission
            Count                     Measure         Public process      Action       Implementation     reductions       reductions     Current status
                                                          begins                           begins           (tpd)            (tpd)             \a\
 
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                            2016 State SIP Strategy Measures
--------------------------------------------------------------------------------------------------------------------------------------------------------
1............................  Lower Opacity Limits             2016            2018  2018-2024......  6.8............  <0.1...........  Adopted July
                                for Heavy-Duty                                                                                            25, 2018.
                                Vehicles.
2............................  Amended Warranty                 2016            2018  2022...........  ...............  ...............  Adopted June
                                Requirements for                                                                                          28, 2018.
                                Heavy-Duty Vehicles.
3............................  Heavy-Duty Vehicle               2019            2020  2022 +.........  ...............  ...............  Public process
                                Inspection and                                                                                            began February
                                Maintenance (I/M)                                                                                         11, 2019.
                                Program.
4............................  Heavy-Duty Low-NOX               2016            2019  2023...........  0.7............  ...............  Public process
                                Engine Standard--                                                                                         began November
                                California Action.                                                                                        3, 2016.

[[Page 17414]]

 
5............................  Innovative Clean                 2015       2018-2019  2020...........  <0.1...........  <0.1...........  Adopted
                                Transit.                                                                                                  December 14,
                                                                                                                                          2018.
6............................  Advanced Clean Local             2016            2019  2020...........  <0.1...........  <0.1...........  Public process
                                Trucks (Last Mile                                                                                         began November
                                Delivery).                                                                                                1, 2016.
7............................  Zero-Emission Airport            2017            2018  2023...........  NYQ............  NYQ............  Adopted June
                                Shuttle Buses.                                                                                            27, 2019.
8............................  Zero-Emission Off-               2020            2020  2023...........  ...............  ...............  Public process
                                Road Forklift                                                                                             to begin 2020.
                                Regulation Phase 1.
9............................  Zero-Emission Airport            2018            2019  2023...........  <0.1...........  <0.1...........  Public process
                                Ground Support                                                                                            began June 6,
                                Equipment.                                                                                                2018.
10...........................  Small Off-Road                   2016       2018-2020  2022...........  0.1............  <0.1...........  Public process
                                Engines.                                                                                                  began May 23,
                                                                                                                                          2016.
11...........................  Transport                        2016       2018-2019  2020 +.........  NYQ............  NYQ............  Public process
                                Refrigeration Units                                                                                       began April
                                Used for Cold                                                                                             13, 2016.
                                Storage.
12...........................  Low-Emission Diesel              2019            2021  2023...........  0.8............  0.1............  Public process
                                Fuel Requirement.                                                                                         began October
                                                                                                                                          18, 2019.
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                           Proposed State Measures for the Valley (Valley State SIP Strategy)
--------------------------------------------------------------------------------------------------------------------------------------------------------
13...........................  Accelerated Turnover             2018         by 2021  Ongoing........  10.............  NYQ............  Public process
                                of Trucks and Buses                                                                                       to begin by
                                Incentive Projects                                                                                        2021.
                                \b\.
14...........................  Accelerated Turnover             2018         by 2020  Ongoing........  Existing 3; New  Existing 0.2;    CARB adopted
                                of Agricultural                                                         8.               New 0.6.         December 12,
                                Equipment Incentive                                                                                       2019.
                                Projects \b\.
15...........................  Accelerated Turnover             2020         by 2021  Ongoing........  2..............  NYQ............  Public process
                                of Off-Road                                                                                               to begin by
                                Equipment Incentive                                                                                       2021.
                                Projects \b\.
                                                                                                      --------------------------------------------------
                              Total Estimated Emission Reductions (tpd)                                32.............  1
--------------------------------------------------------------------------------------------------------------------------------------------------------
Sources: 2018 PM2.5 Plan, Tables 4-8 and 4-9 and email dated November 12, 2019, from Sylvia Vanderspek, CARB to Anita Lee, EPA Region IX, ``RE: SJV
  PM2.5 information'' (attaching ``Valley State SIP Strategy Progress'').
NYQ means ``not yet quantified.''
\a\ For references on the current status of these measures, see section VIII of the EPA's General Evaluation TSD.
\b\ Indicates that CARB intends to develop a SIP-creditable measure to demonstrate that the emission reductions from incentive projects can be credited
  towards the aggregate commitment.

    In November 2019, the District also provided status updates on its 
progress to date on developing and adopting the additional stationary 
source measures identified in its control measure commitment.\340\ 
Table 8 lists each measure and provides a summary of the anticipated 
emission reductions and the current status for each measure. As shown 
in the ``Current Status'' column, the District has adopted and 
submitted one of these measures (the 2019 amendment to Rule 4901) to 
the EPA for approval into the SIP and has begun the public process on 
five of the remaining 11 measures listed in its control measure 
commitment.\341\
---------------------------------------------------------------------------

    \340\ Email dated November 12, 2019, from Jon Klassen, SJVUAPCD 
to Wienke Tax, EPA Region IX, ``RE: follow up on aggregate 
commitments in SJV PM2.5 plan'' (attaching ``District 
Progress In Implementing Commitments with 2018 PM2.5 
Plan'').
    \341\ The EPA has recently proposed to approve amended Rule 4901 
into the California SIP. 85 FR 1131.

                           Table 8--Status of SJVUAPCD Compliance with Control Measure Commitments for the San Joaquin Valley
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                          Direct PM2.5
                                                                                                         NOX emission       emission
            Count                     Measure         Public process    Action date    Implementation     reductions       reductions     Current status
                                                          begins                           begins           (tpd)            (tpd)             \a\
 
--------------------------------------------------------------------------------------------------------------------------------------------------------
1............................  Rule 4311                        2018            2020  2023...........  0.05...........  ...............  Public workshop
                                (``Flares'').                                                                                             held November
                                                                                                                                          13, 2019.
2............................  Rule 4306 (``Boilers,            2019            2020  2023...........  0.76...........  0.03...........  Public scoping
                                Steam Generators,                                                                                         meeting held
                                and Process Heaters--                                                                                     December 5,
                                Phase 3'').                                                                                               2019.
3............................  Rule 4320 (``Advanced  ..............  ..............  ...............  ...............  ...............  Public scoping
                                Emission Reduction                                                                                        meeting held
                                Options for Boilers,                                                                                      December 5,
                                Steam Generators,                                                                                         2019.
                                and Process Heaters
                                Greater than 5.0
                                MMBtu/hr'').
4............................  Rule 4354 (``Glass               2020            2021  2023...........  ...............  ...............  Public process
                                Melting Furnaces'').                                                                                      to begin in
                                                                                                                                          2020.
5............................  Rule 4352 (``Solid               2020            2021  2023...........  ...............  ...............  Public process
                                Fuel-Fired Boilers,                                                                                       to begin in
                                Steam Generators and                                                                                      2020.
                                Process Heaters'').
6............................  Rule 4702 (``Internal            2019            2020  2024...........  ...............  ...............  Public scoping
                                Combustion                                                                                                meeting held
                                Engines'').                                                                                               December 5,
                                                                                                                                          2019.
7............................  Rule 4550                        2021            2022  2024...........  ...............  0.32...........  Public process
                                (``Conservation                                                                                           to begin in
                                Management                                                                                                2021.
                                Practices'').
8............................  Rule 4692                        2019            2020  2024...........  ...............  ...............  Public scoping
                                (``Commercial Under-                                                                                      meeting held
                                fired                                                                                                     December 12,
                                Charbroilers'').                                                                                          2019.

[[Page 17415]]

 
9............................  Rule 4901                        2019            2019  2019...........  ...............  0.26...........  Rule adopted
                                (``Woodburning                                                                                            June 20, 2019
                                Fireplaces and Wood                                                                                       and submitted
                                Burning Heaters'')                                                                                        to EPA July
                                (Hot-spot strategy).                                                                                      22, 2019.
10...........................  Agricultural                     2019            2020  Ongoing........  1.07...........  ...............  Public process
                                Operation Internal                                                                                        pending.
                                Combustion Engines
                                Incentive Projects.
11...........................  Commercial Under-                2019            2020  Ongoing........  ...............  0.53...........  Public process
                                fired.                                                                                                    pending.
                               Charbroiling
                                Incentive Projects.
12...........................  Residential Wood                 2019            2020  Ongoing........  ...............  0.16...........  Public process
                                Burning Devices                                                                                           pending.
                                Incentive Projects.
                                                                                                      --------------------------------------------------
                              Total Estimated Emission Reductions (tpd)                                1.88...........  1.3
--------------------------------------------------------------------------------------------------------------------------------------------------------
Sources: 2018 PM2.5 Plan, Chapter 4, Tables 4-3, 4-4, and 4-5 and Appendix E, Table E-3; SJVUAPCD, Final Draft Staff Report, ``Amendments to District's
  Residential Wood Burning Emission Reduction Strategy,'' June 20, 2019 (``2019 Rule 4901 Staff Report''); and email dated November 12, 2019, from Jon
  Klassen, SJVUAPCD to Wienke Tax, EPA Region IX, ``RE: follow up on aggregate commitments in SJV PM2.5 plan'' (attaching ``District Progress In
  Implementing Commitments with 2018 PM2.5 Plan'').
\a\ For references on the current status of these measures, see section VIII of the EPA's General Evaluation TSD.

    With respect to Rule 4901 (``Wood Burning Fireplaces and Wood 
Burning Heaters''), the District amended this rule on June 20, 2019, to 
establish more stringent limitations on the use of residential wood 
burning devices. Specifically, the June 20, 2019 amendment to Rule 4901 
lowered the thresholds at which ``No Burn'' days will be imposed to 
limit direct PM2.5 emissions from residential wood burning 
during the November through February timeframe in three ``hot spot'' 
counties (Fresno, Kern, and Madera).\342\ CARB submitted this amended 
rule to the EPA on July 22, 2019, and the EPA has proposed to approve 
the amended rule into the California SIP.\343\ The EPA approved a prior 
version of this rule into the SIP on October 6, 2016.\344\ The 
District's control measure commitment for 2024 and 2025 in Chapter 4 of 
the 2018 PM2.5 Plan indicates that the District expects to 
achieve 0.42 tpd of direct PM2.5 emission reductions through 
implementation of its residential wood burning strategy, including 
implementation of the ``No Burn'' provisions in amended Rule 4901.\345\ 
Upon the EPA's final action to approve amended Rule 4901 into the SIP, 
the additional emission reductions resulting from the ``No Burn'' 
provisions of the amended rule may be credited toward the attainment 
demonstration in the Plan.
---------------------------------------------------------------------------

    \342\ The revised rule adds additional restrictions on the 
installation of wood burning devices, new requirements for fireplace 
and chimney remodel projects, additional requirements for 
residential real estate sales, non-seasoned wood to the list of 
prohibited fuel types, a new visible emissions limit for fireplaces 
and non-registered devices, and other editorial revisions to improve 
rule clarity. The emission reductions from these additional 
revisions were not quantified.
    \343\ 85 FR 1131.
    \344\ 81 FR 69393 (October 6, 2016) (approving Rule 4901 as 
amended September 18, 2014).
    \345\ 2018 PM2.5 Plan, Ch. 4, Table 4-3.
---------------------------------------------------------------------------

    We note that the District's current estimate of direct 
PM2.5 emission reductions to be achieved through the ``No 
Burn'' provisions of amended Rule 4901 (0.26 tpd) is based on a 
compliance rate (referred to as a ``control efficiency'') of 100%. The 
District estimates an actual control efficiency of 97% to 99%, based on 
the District's surveillance of neighborhoods in the San Joaquin 
Valley.\346\ This control efficiency is significantly higher than the 
75% control efficiency that EPA guidance attributes to wood burning 
curtailment programs.\347\ Because the District has not provided 
adequate support for a 97-100% rule effectiveness rate, we are 
crediting the amended rule at this time with 0.20 tpd of direct 
PM2.5 emission reductions toward the attainment control 
strategy, based on a 75% control efficiency. We have factored this 
amount into the direct PM2.5 emission reductions from 
approved measures, shown in Row C of Table 9.
---------------------------------------------------------------------------

    \346\ Email dated October 9, 2019 from Jon Klassen, SJVUAPCD to 
Meredith Kurpius, EPA Region IX, Subject: ``RE: Info to support Rule 
4901.''
    \347\ Strategies for Reducing Wood Smoke, EPA-456/B-13-01, March 
2013, 42.
---------------------------------------------------------------------------

    Table 9 provides a summary of the total NOX and direct 
PM2.5 emission reductions necessary for attainment in the 
San Joaquin Valley by December 31, 2024, the emission reductions 
attributed to baseline measures and new control strategy measures, and 
the emission reductions remaining as aggregate tonnage commitments. 
Approximately 13.8% of the NOX reductions necessary for 
attainment and 26.6% of the direct PM2.5 reductions 
necessary for attainment remain as aggregate tonnage commitments.

                   Table 9--Reductions Needed for Attainment and Aggregate Tonnage Commitments
                                                   [tpd, 2024]
----------------------------------------------------------------------------------------------------------------
                                                                                                   Direct PM2.5
                                                                                        NOX
----------------------------------------------------------------------------------------------------------------
A.....................................  Total reductions needed from baseline              202.2             6.4
                                         and control strategy measures.
B.....................................  Reductions from baseline measures.......           168.3             4.2
C.....................................  Total reductions from approved measures.             5.9             0.5
D.....................................  Total reductions remaining as                       28.0             1.7
                                         commitments (A-B-C).
E.....................................  Percent of total reductions needed                 13.8%           26.6%
                                         remaining as commitments (D/A).
----------------------------------------------------------------------------------------------------------------
Sources: 2018 PM2.5 Plan, Ch. 4, Tables 4-3 and 4-7, and Appendix B, Tables B-1 and B-2; 2019 Rule 4901 Staff
  Report, 34; and ``Air Plan Approval; California; San Joaquin Valley Unified Air Pollution Control District''
  (proposed rule to approve ``San Joaquin Valley Agricultural Equipment Incentive Measure''), pre-publication
  notice signed February 13, 2020.


[[Page 17416]]

    The CAA allows for approval of enforceable commitments that are 
limited in scope where circumstances exist that warrant the use of such 
commitments in place of adopted measures.\348\ Specifically, CAA 
section 110(a)(2)(A) provides that each SIP ``shall include enforceable 
emission limitations and other control measures, means or techniques . 
. . as well as schedules and timetables for compliance, as may be 
necessary or appropriate to meet the applicable requirement of the 
Act.'' Section 172(c)(6) of the Act, which applies to nonattainment 
SIPs, is virtually identical to section 110(a)(2)(A). The language in 
these sections of the CAA is quite broad, allowing a SIP to contain any 
``means or techniques'' that the EPA determines are ``necessary or 
appropriate'' to meet CAA requirements, such that the area will attain 
as expeditiously as practicable, but no later than the designated date. 
Furthermore, the express allowance for ``schedules and timetables'' 
demonstrates that Congress understood that all required controls might 
not have to be in place before a SIP could be fully approved.
---------------------------------------------------------------------------

    \348\ Commitments approved by the EPA under CAA section 
110(k)(3) are enforceable by the EPA and citizens under CAA sections 
113 and 304, respectively. In the past, the EPA has approved 
enforceable commitments and courts have enforced these actions 
against states that failed to comply with those commitments. See, 
e.g., American Lung Ass'n of N.J. v. Kean, 670 F. Supp. 1285 (D.N.J. 
1987), aff'd, 871 F.2d 319 (3rd Cir. 1989); NRDC, Inc. v. N.Y. State 
Dept. of Env. Cons., 668 F. Supp. 848 (S.D.N.Y. 1987); Citizens for 
a Better Env't v. Deukmejian, 731 F. Supp. 1448, recon. granted in 
par, 746 F. Supp. 976 (N.D. Cal. 1990); Coalition for Clean Air v. 
South Coast Air Quality Mgt. Dist., No. CV 97-6916-HLH, (C.D. Cal. 
Aug. 27, 1999). Further, if a state fails to meet its commitments, 
the EPA could make a finding of failure to implement the SIP under 
CAA section 179(a), which starts an 18-month period for the State to 
correct the non-implementation before mandatory sanctions are 
imposed.
---------------------------------------------------------------------------

    Once the EPA determines that circumstances warrant consideration of 
an enforceable commitment to satisfy a CAA requirement, it considers 
three factors in determining whether to approve the enforceable 
commitment: (a) Does the commitment address a limited portion of the 
CAA requirement; (b) is the state capable of fulfilling its commitment; 
and (c) is the commitment for a reasonable and appropriate period of 
time.\349\
---------------------------------------------------------------------------

    \349\ The Fifth Circuit Court of Appeals upheld the EPA's 
interpretation of CAA sections 110(a)(2)(A) and 172(c)(6) and the 
Agency's use and application of the three factor test in approving 
enforceable commitments in the 1-hour ozone SIP for Houston-
Galveston. BCCA Appeal Group et al. v. EPA et al., 355 F.3d 817 (5th 
Cir. 2003). More recently, the Ninth Circuit Court of Appeals upheld 
the EPA's approval of enforceable commitments in ozone and 
PM2.5 SIPs for the San Joaquin Valley, based on the same 
three factor test. Committee for a Better Arvin, et al. v. EPA, 786 
F.3d 1169 (9th Cir. 2015).
---------------------------------------------------------------------------

    With respect to the SJV PM2.5 Plan, circumstances 
warrant the consideration of enforceable commitments as part of the 
attainment demonstration for this area. As shown in Table 9 of this 
preamble, the majority of the emissions reductions needed to 
demonstrate attainment and RFP in the San Joaquin Valley are achieved 
by rules and regulations adopted prior to the State's development of 
the SJV PM2.5 Plan, i.e., baseline measures. As a result of 
these already-adopted State and District measures, most air pollution 
sources in the San Joaquin Valley were already subject to stringent 
rules prior to the development of the SJV PM2.5 Plan, 
leaving fewer and more technologically-challenging opportunities to 
reduce emissions. Despite these significant emission reductions, as 
shown in Table 6 of this preamble, the San Joaquin Valley area needs to 
reduce NOX and direct PM2.5 emission levels by a 
total of 63.7% and 10.2%, respectively, from 2013 base year levels in 
order to attain the 2006 PM2.5 NAAQS by the end of 2024.
    As part of their respective control measure commitments in the SJV 
PM2.5 Plan, CARB and the District each have identified 
potential control measures that are expected to achieve the additional 
emissions reductions needed for attainment. The timeline needed to 
develop, adopt, and implement these measures, however, goes well beyond 
the December 31, 2019 serious area attainment date for the 2006 
PM2.5 NAAQS in this area. Both the State and District are 
making progress in adopting the rules and measures listed in their 
respective control measure commitments but have not yet completely 
fulfilled them. Given these circumstances, we find that the State's and 
District's reliance on enforceable commitments in the SJV 
PM2.5 Plan is warranted. Therefore, we have considered the 
three factors the EPA uses to determine whether the use of enforceable 
commitments in lieu of adopted measures satisfies CAA planning 
requirements.
(a) The Commitment Represents a Limited Portion of Required Reductions
    For the first factor, we look to see if the commitment addresses a 
limited portion of a statutory requirement, such as the amount of 
emissions reductions needed to attain the NAAQS in a nonattainment 
area. As shown in Table 9 of this preamble, most of the total emission 
reductions needed to attain the 2006 PM2.5 NAAQS in the San 
Joaquin Valley by the end of 2024 will be achieved through 
implementation of both baseline and new measures, leaving 13.8% (28.0 
tpd) of the necessary NOX reductions and 26.6% (1.7 tpd) of 
the necessary direct PM2.5 reductions as aggregate tonnage 
commitments.
    Given the nature of the PM2.5 challenge in the San 
Joaquin Valley, the significant reductions in NOX and direct 
PM2.5 emission levels achieved through implementation of 
baseline measures over the past several decades, and the difficulty of 
identifying additional control measures that are feasible for 
implementation in the area, we find it reasonable for the State and 
District to seek additional time to adopt the last increment of 
emission reductions necessary for attainment by 2024.
    Therefore, we find that the emission reductions remaining as 
enforceable commitments in the SJV PM2.5 Plan represent a 
limited portion of the total emissions reductions needed to demonstrate 
attainment by December 31, 2024.
(b) The State Is Capable of Fulfilling Its Commitment
    For the second factor, we consider whether the State and District 
are capable of fulfilling their commitments. CARB and the District 
recently provided updates on their progress in developing and adopting 
the additional mobile source and stationary source measures listed in 
their respective control measure commitments. Specifically, as shown in 
Table 7 of this preamble, CARB has adopted four of the 12 regulatory 
measures listed in its control measure commitment, including heavy-duty 
vehicle opacity limits, heavy-duty vehicle warranty requirements, 
Innovative Clean Transit, and Zero-Emission Airport Shuttle Buses. CARB 
has also begun the public process on seven of the remaining eight 
regulatory measures listed in CARB's control measure commitment. 
Additionally, on December 12, 2019, CARB adopted the San Joaquin Valley 
Agricultural Incentive Measure, one of the three incentive-based 
measures identified in its control measure commitment. CARB submitted 
this measure to the EPA on February 11, 2020, and the EPA has proposed 
to approve it as a revision to the California SIP.\350\
---------------------------------------------------------------------------

    \350\ Letter dated February 11, 2020, from Richard Corey, 
Executive Officer, CARB, to Mike Stoker, Regional Administrator, EPA 
Region 9, and ``Air Plan Approval; California; San Joaquin Valley 
Unified Air Pollution Control District'' (proposed rule to approve 
``San Joaquin Valley Agricultural Equipment Incentive Measure''), 
pre-publication notice signed February 13, 2020.

---------------------------------------------------------------------------

[[Page 17417]]

    For CARB's Heavy Duty I/M Program, in addition to the February 11, 
2019 workshop, CARB has held three other workshops in 2019.\351\ With 
the passage of California Senate Bill 210, the Heavy Duty I/M Program 
will be considered for Board action in 2020.\352\ For CARB's Heavy-Duty 
Low-NOX Engine Standard, following the November 3, 2016 
public workshop, CARB held six additional workshops between 2017 and 
2019.\353\ For the Zero-Emission Airport Ground Support Equipment, CARB 
held a workshop on August 2, 2018.\354\ For the Small Off-Road Engines 
measure, CARB has held five additional working group meetings and three 
public workshops between 2017 and 2019.\355\ For Transport 
Refrigeration Units Used for Cold Storage, CARB held additional 
workshops in 2017 and most recently in October 2019.\356\
---------------------------------------------------------------------------

    \351\ Information about the proposed Heavy-Duty I/M Program is 
available at https://ww2.arb.ca.gov/our-work/programs/inspection-and-maintenance-program/Meetings-and-Workshops.
    \352\ SB 210 was signed by the California Governor and filed 
with the Secretary of State on September 20, 2019.
    \353\ Information about the proposed Heavy-Duty Low-
NOX Engine Standard is available at https://ww2.arb.ca.gov/our-work/programs/heavy-duty-low-nox/heavy-duty-low-nox-meetings-workshops.
    \354\ Information about the proposed Zero-Emission Airport 
Ground Support Equipment regulation is available at https://ww2.arb.ca.gov/our-work/programs/zero-emission-airport-ground-support-equipment/ze-airport-gse-meetings-workshops.
    \355\ Information about the proposed Small Off-Road Engines 
measure is available at https://ww2.arb.ca.gov/our-work/programs/small-off-road-engines-sore/resources and https://ww2.arb.ca.gov/sore-workshops.
    \356\ Information about the proposed Transport Refrigeration 
Units Used for Cold Storage measure is available at https://ww2.arb.ca.gov/our-work/programs/transport-refrigeration-unit/tru-meetings-workshops.
---------------------------------------------------------------------------

    CARB continues to pursue additional control strategies to reduce 
emissions in California's nonattainment areas. For example, ongoing 
CARB programs that address zero emission airport shuttle buses and 
transportation refrigeration units used for cold storage have yet to be 
quantified but are expected to further reduce NOX and direct 
PM2.5 emissions in the San Joaquin Valley by 2024.\357\ 
Additionally, as part of the development of a draft plan submission to 
address attainment of the ozone NAAQS in the South Coast, CARB has 
identified a number of potential new state control measures that would 
achieve NOX and direct PM2.5 emission reductions 
not only in the South Coast but also in the San Joaquin Valley.\358\ 
These include a Tier 5 non-road diesel engine standard, a state green 
contracting measure, a measure to reduce single occupancy vehicle 
travel, and a locomotive emission reduction measure.
---------------------------------------------------------------------------

    \357\ 2018 PM2.5 Plan, Chapter 4, Table 4-9.
    \358\ CARB, ``2019 South Coast 8-hour Ozone SIP Update,'' 
December 12, 2019. See also CARB Resolution 19-31 (December 12, 
2019). Further information about this SIP revision is available at 
https://ww3.arb.ca.gov/planning/sip/planarea/scabsip/scabsip.htm#2019o3.
---------------------------------------------------------------------------

    Similarly, the District has made progress in meeting its control 
measure commitments for the San Joaquin Valley. As shown in Table 8 of 
this preamble, following an initial December 2018 public workshop, the 
District adopted amendments to Rule 4901 on June 20, 2019, and CARB 
submitted the amended rule to the EPA on July 22, 2019.\359\ The 
amendments to Rule 4901 include lowering the residential wood burning 
curtailment thresholds for Madera, Fresno, and Kern Counties in 
addition to Valley-wide rule enhancements. The EPA has proposed to 
approve amended Rule 4901 into the California SIP.\360\
---------------------------------------------------------------------------

    \359\ Letter dated July 19, 2019, from Richard Corey, Executive 
Officer, CARB, to Mike Stoker, Regional Administrator, EPA Region 9.
    \360\ 85 FR 1131.
---------------------------------------------------------------------------

    Additionally, the District has started a public process for five of 
the remaining eight regulatory measures, including each of the five 
regulatory measures for which it committed to do so by 2019 or earlier. 
Specifically, on August 23, 2017, the District hosted an initial public 
scoping meeting on potential amendments to Rule 4311 (``Flares''), and 
on November 13, 2019, the District hosted a public workshop on 
potential amendments to the rule.\361\ These potential amendments 
include additional flare minimization requirements, where 
technologically achievable and economically feasible, and additional 
ultra-low NOX flare emission limitations for existing and 
new flaring activities at Valley facilities, where technologically 
achievable and economically feasible.
---------------------------------------------------------------------------

    \361\ For more information on this workshop, see https://www.valleyair.org/Workshops/postings/2019/11-13-19_Flares/presentation.pdf.
---------------------------------------------------------------------------

    For the remaining four measures in the District's control measure 
commitment, on June 21, 2018, the District adopted amendments to Rule 
4692 that require commercial cooking operations with UFCs to report by 
January 1, 2019, on the type and quantity, in pounds, of meat cooked on 
the UFCs on a weekly basis for the previous 12-month period as well as 
other information regarding the nature of their operations, and for 
certain such operations to register with the District and keep weekly 
records relating to the quantities of meat cooked. This is an important 
first step in the District's development of a new control measure for a 
source category not previously subject to direct PM2.5 
emission control requirements in the San Joaquin Valley. The District 
hosted a public scoping workshop for Rule 4692 on December 12, 
2019,\362\ and a scoping meeting for Rule 4306 and Rule 4320 on 
December 5, 2019.\363\ Finally, the District held a scoping meeting for 
Rule 4702, also on December 5, 2019.\364\
---------------------------------------------------------------------------

    \362\ More information on the public scoping workshop on Rule 
3692 can be found at https://www.valleyair.org/Workshops/postings/2019/12-12-19_CC/presentation.pdf.
    \363\ More information on the scoping workshop for Rules 4306 
and 4320 can be found at https://www.valleyair.org/Workshops/postings/2019/12-05-19_BGH/presentation.pdf.
    \364\ Information on the scoping meeting on Rule 4702 can be 
found at https://www.valleyair.org/Workshops/postings/2019/12-05-19_ICE/presentation.pdf.
---------------------------------------------------------------------------

    Beyond the rules discussed above, both CARB and the District have 
well-funded incentive grant programs to reduce emissions from mobile, 
stationary, and area sources in the San Joaquin Valley. Funding for the 
State's incentive programs in the San Joaquin Valley comes from various 
sources including the Carl Moyer Program, Proposition 1B Goods Movement 
Emission Reduction Program, Greenhouse Gas Reduction Fund, and the 
Funding Agricultural Replacement Measures for Emission Reductions 
(FARMER) program.\365\ Funding for the District's incentive programs 
comes from a combination of federal, State, and local funding 
mechanisms, including the Diesel Emission Reduction Act (DERA) and 
Target Airshed Grant programs, the Carl Moyer Program, and fees 
assessed in the San Joaquin Valley by the California Department of 
Motor Vehicles and by the District through programs for Indirect Source 
Review, Voluntary Emission Reduction Agreements, and large boilers, 
steam generators, and process heaters.\366\
---------------------------------------------------------------------------

    \365\ 2018 PM2.5 Plan, App. E, E-6.
    \366\ Id.
---------------------------------------------------------------------------

    Collectively, these incentive funds have been applied to a wide 
range of emission sources, including heavy-duty trucks, light-duty 
vehicles, mobile agricultural equipment, locomotives, school buses, 
alternative fuel infrastructure, community-based programs, agricultural 
irrigation pumps, residential wood combustion devices, and commercial 
charbroilers.\367\ The Plan identifies the total funding need for 
expeditious attainment as $5 billion, including $3.3 billion for heavy-
duty trucks and buses and $1.4 billion for mobile agricultural 
equipment.\368\
---------------------------------------------------------------------------

    \367\ Id. at App. E, E-8 to E-21.
    \368\ Id. at App. E, Table E-4 (``Incentive Funding Needed for 
Expeditious Attainment''). The CARB Staff Report describes the 
status of current incentive funding and CARB's expectations 
concerning future incentive funding out to 2024 for the San Joaquin 
Valley. CARB Staff Report, section F (``Status of Incentive 
Funding''), 24-27.

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[[Page 17418]]

    We note that, during CARB's September 19, 2019 hearing on the SJV 
PM2.5 Plan, community and environmental advocacy groups 
raised concerns that incentive funding recently appropriated fell short 
of the Plan's needs and requested that the State pursue alternative 
measures to obtain emission reductions from specific stationary sources 
in the San Joaquin Valley.\369\ In response to these concerns and 
similar concerns raised by CARB Governing Board Member Dean Florez, 
CARB committed to follow-up with the District and stakeholders and to 
hold public workshops in the San Joaquin Valley to discuss additional 
emission reduction opportunities.\370\
---------------------------------------------------------------------------

    \369\ Letter dated September 17, 2019, from Genevieve Gale, 
Central Valley Air Quality (CVAQ) Coalition, et al to CARB Board 
Members and Staff.
    \370\ J&K Court Reporting, LLC, ``Meeting, State of California 
Air Resources Board,'' September 19, 2019 (transcript of CARB's 
public hearing), 100.
---------------------------------------------------------------------------

    We note also that the State and District will have to submit to the 
EPA, for SIP approval, any control measure that it intends to rely on 
to satisfy the aggregate tonnage commitments in the Plan. Where the 
State or District intends to substitute reductions in one pollutant to 
achieve a tonnage commitment concerning a different pollutant (e.g., 
substituting NOX reductions to satisfy a direct 
PM2.5 reduction commitment), it must include an appropriate 
inter-pollutant trading (IPT) ratio and the technical basis for such 
ratio. The EPA will review any such IPT ratio and its bases before 
approving or disapproving the measure.
    Given the evidence of the State's and District's progress to date 
in proposing and adopting the measures listed in their respective 
control measure commitments and their continuing efforts to develop 
additional control measures to further reduce NOX and 
PM2.5 emissions in the San Joaquin Valley, we find that the 
State and District are capable of meeting their commitments.
(c) The Commitment Is for a Reasonable and Appropriate Timeframe
    For the third and last factor, we consider whether the commitment 
is for a reasonable and appropriate period of time. As discussed in 
section II.B of this preamble, on March 23, 2017, CARB adopted the 2016 
State Strategy and directed staff to return to the Board with a 
commitment to achieve additional emission reductions from mobile 
sources in the San Joaquin Valley.\371\ CARB responded by developing 
the Valley State SIP Strategy, which includes additional state 
commitments to achieve accelerated emission reductions for purposes of 
attaining the PM2.5 NAAQS in the San Joaquin Valley.
---------------------------------------------------------------------------

    \371\ CARB Resolution 17-7 (March 23, 2017), page 7.
---------------------------------------------------------------------------

    In the Valley State SIP Strategy, CARB recognized that the earlier 
attainment dates for the 1997, 2006, and 2012 PM2.5 NAAQS in 
the San Joaquin Valley compared to ozone attainment dates in the San 
Joaquin Valley and elsewhere in the State required accelerating the 
pace of NOX reductions.\372\ Thus, in the Valley State SIP 
Strategy CARB identified and committed to achieve emission reductions 
of 32 tpd of NOX and 0.9 tpd of direct PM2.5 by 
2024,\373\ significantly greater amounts than those CARB had committed 
to in the 2016 State Strategy (6 tpd of NOX and 0.1 tpd of 
direct PM2.5 by 2025).\374\ CARB defined the estimate of 
emission reductions by 2024 from the lower in-use performance level of 
heavy-duty trucks as 6.8 tpd of NOX, representing the 
largest emission reduction among the additional prohibitory 
measures.\375\
---------------------------------------------------------------------------

    \372\ Valley State SIP Strategy, 2-3 and 6.
    \373\ CARB Resolution 18-49 (October 25, 2018), page 5.
    \374\ CARB Resolution 17-7 (March 23, 2017), paragraph 7.
    \375\ 2018 PM2.5 Plan, Ch. 4, Table 4-9.
---------------------------------------------------------------------------

    The SJV PM2.5 Plan includes specific rule development, 
adoption, and implementation schedules designed to meet the State's and 
District's commitments to reduce emissions to the levels needed to 
attain the 2006 PM2.5 NAAQS in the San Joaquin Valley by 
2024. For example, the aggregate commitments in the SJV 
PM2.5 Plan include commitments by both the State and the 
District to begin the public process on each of their respective 
control measure commitments by specific dates ranging from 2015 to 
2021. The commitments also identify action and implementation dates 
ranging from 2018 to 2024 for a number of State and District control 
measures, including amendments to SJVUAPCD Rule 4901, Rule 4311, Rule 
4306, Rule 4320, Rule 4354, and Rule 4352.\376\
---------------------------------------------------------------------------

    \376\ 2018 PM2.5 Plan, Ch. 4, Tables 4-4, 4-5, and 4-
8.
---------------------------------------------------------------------------

    We find that these schedules provide a reasonable and appropriate 
amount of time for the State and District to achieve the remaining 
emission reductions necessary to the attain the 2006 24-hour 
PM2.5 NAAQS in the San Joaquin Valley by December 31, 2024. 
We therefore conclude that the third factor is satisfied.
c. Conclusion
    The EPA must make several findings in order to approve the modeled 
attainment demonstration in an attainment plan SIP submission. First, 
we must find that the attainment demonstration's technical bases, 
including the emissions inventories and air quality modeling, are 
adequate. As discussed in sections IV.A and IV.D.4.a of this preamble, 
we are proposing to approve both the emissions inventories and the air 
quality modeling on which the SJV PM2.5 Plan's attainment 
demonstration and related provisions are based.
    Second, we must find that the SIP submittal provides for 
expeditious attainment through the timely implementation of all BACM 
and BACT. As discussed in section IV.C of this preamble, we are 
proposing to approve the BACM/BACT demonstration in the SJV 
PM2.5 Plan.
    Third, the EPA must find that the emissions reductions that are 
relied on for attainment in the SIP submission are creditable. As 
discussed in section IV.D.4, the SJV PM2.5 Plan relies 
principally on already adopted and approved rules to achieve the 
emissions reductions needed to attain the 2006 24-hour PM2.5 
standards in the San Joaquin Valley by December 31, 2024. The balance 
of the reductions is currently in the form of enforceable commitments 
that account for 13.8% of the NOX and 26.6% of the direct 
PM2.5 emissions reductions needed for attainment, as shown 
in Table 9 of this preamble.
    The EPA has previously accepted enforceable commitments in lieu of 
adopted control measures in attainment demonstrations when the 
circumstances warrant it and the commitments meet three criteria. As 
discussed herein, we find that circumstances here warrant the 
consideration of enforceable commitments and that the three criteria 
are met: (1) The commitments constitute a limited portion of the 
required emissions reductions, (2) both the State and the District have 
demonstrated their capability to meet their commitments, and (3) the 
commitments are for an appropriate timeframe. We therefore propose to 
allow the State to rely on these enforceable commitments in its 
attainment demonstration.
    Based on these evaluations, we propose to determine that the SJV 
PM2.5 Plan provides for attainment of the 2006 24-hour 
PM2.5 NAAQS by the most expeditious alternative date 
practicable, consistent with the requirements of CAA sections 
189(b)(1)(A) and 188(e).

[[Page 17419]]

5. Application for an Attainment Date Extension
    As discussed in section I of this preamble, the Serious area 
attainment date for the San Joaquin Valley for the 2006 24-hour 
PM2.5 NAAQS under CAA section 188(c)(2) is December 31, 
2019. The first criterion for an extension of the attainment date 
beyond this statutory attainment date is that the State must apply for 
such extension. In the SJV PM2.5 Plan, CARB and SJVUAPCD 
submitted a complete application for an extension of the Serious area 
attainment date for the SJV to December 31, 2024, for the 2006 
PM2.5 NAAQS.\377\ In accordance with the requirements of the 
PM2.5 SIP Requirements Rule in 40 CFR 51.1005(b)(2), the SJV 
PM2.5 Plan contains all of the required components of a 
Serious area plan containing a request for extension of the attainment 
date under CAA section 188(e), as follows: (1) Base year and attainment 
projected emissions inventories, (2) provisions to implement MSM and 
BACM, (3) a modeled attainment demonstration, (4) reasonable further 
progress provisions, (5) quantitative milestone provisions, (6) 
contingency measure provisions, and (7) nonattainment new source review 
plan provisions.\378\
---------------------------------------------------------------------------

    \377\ CARB Resolution 19-1 (January 24, 2019), (submitting the 
Plan to EPA as a SIP revision), SJVUAPCD Governing Board Resolution 
18-11-16 (November 15, 2018), paragraph 1 (adopting the 2018 
PM2.5 Plan), and 2018 PM2.5 Plan, Ch. 6, 6-1 
to 6-2.
    \378\ Letter dated May 9, 2019, from Richard Corey, Executive 
Officer, CARB, to Mike Stoker, Regional Administrator, EPA Region 9 
(transmitting adopted SJV PM2.5 Plan) and letter dated 
November 15, 2019, from Richard Corey, Executive Officer, CARB, to 
Mike Stoker, Regional Administrator, EPA Region 9 (transmitting 
adopted nonattainment new source review rules for the San Joaquin 
Valley).
---------------------------------------------------------------------------

    Based on our evaluation of the Plan, we propose to grant the 
State's request to extend the Serious area attainment deadline from 
December 31, 2019, to December 31, 2024, for the 2006 PM2.5 
NAAQS in the San Joaquin Valley. We are requesting public comment to 
ensure that the EPA fully considers all relevant factors in evaluating 
the State's request. If based on new information or public comments we 
find that a decision to grant the requested extension would not be 
consistent with the requirements of the Act, the EPA may reconsider 
this proposal or deny California's request to extend the deadline.\379\
---------------------------------------------------------------------------

    \379\ Under CAA section 179(c), the EPA must determine no later 
than 6 months after the applicable attainment date for any 
nonattainment area whether the area attained the NAAQS by that date. 
Absent an extension of the Serious area attainment date under CAA 
section 188(e), the latest permissible attainment date for the 2006 
PM2.5 NAAQS in the San Joaquin Valley Serious 
nonattainment area was December 31, 2019, and the statutory deadline 
under CAA section 179(c) for the EPA to determine whether the area 
attained these NAAQS by the Serious area attainment date is June 30, 
2020. See also Memorandum dated November 14, 1994, from Sally L. 
Shaver, EPA Air Quality Strategies and Standards Division, to EPA 
Air Division directors, Regions I through X, RE: ``Criteria for 
Granting 1-Year Extensions of Moderate PM-10 Nonattainment Area 
Attainment Dates, Making Attainment Determinations, and Reporting on 
Quantitative Milestones,'' 16 (stating that EPA regional offices 
will address state requests for 1-year attainment date extensions 
under CAA section 188(d) no later than 6 months after the applicable 
attainment date). The CAA does not establish a specific deadline for 
the EPA's denial of a request for extension of an attainment date.
---------------------------------------------------------------------------

    If the EPA were to take final action to deny the request for 
extension of the attainment date, the EPA would be required under CAA 
section 179(c) to determine, based on the San Joaquin Valley's air 
quality as of December 31, 2019, whether the area attained the 2006 
PM2.5 NAAQS by that date.

E. Reasonable Further Progress and Quantitative Milestones

1. Statutory and Regulatory Requirements
    Section 172(c)(2) of the Act provides that all nonattainment area 
plans shall require reasonable further progress (RFP) toward 
attainment. In addition, CAA section 189(c) requires that all 
PM2.5 nonattainment area plans contain quantitative 
milestone for purposes of measuring RFP, as defined in CAA section 
171(1), every three years until the area is redesignated to attainment. 
Section 171(1) of the Act defines RFP as the annual incremental 
reductions in emissions of the relevant air pollutant as are required 
by part D, title I of the Act, or as may reasonably be required by the 
Administrator for the purpose of ensuring attainment of the NAAQS by 
the applicable attainment date. Neither subpart 1 nor subpart 4 of part 
D, title I of the Act requires that states achieve a set percentage of 
emissions reductions in any given year for purposes of satisfying the 
RFP requirement.
    For purposes of the particulate matter NAAQS, RFP has historically 
been met by showing annual incremental emissions reductions sufficient 
to maintain ``generally linear progress'' toward attainment by the 
applicable deadline.\380\ As discussed in EPA guidance in the General 
Preamble Addendum, requiring generally linear progress in reductions of 
direct PM2.5 and relevant PM2.5 precursors in a 
PM2.5 attainment plan may be appropriate in situations 
where:
---------------------------------------------------------------------------

    \380\ General Preamble Addendum, 42015.
---------------------------------------------------------------------------

     The pollutant is emitted by a large number and range of 
sources,
     the relationship between any individual source or source 
category and overall air quality is not well known,
     a chemical transformation is involved (e.g., secondary 
particulate significantly contributes to PM2.5 levels over 
the standard), and/or
     the emission reductions necessary to attain the 
PM2.5 standards are inventory-wide.\381\
---------------------------------------------------------------------------

    \381\ Id.
---------------------------------------------------------------------------

    The EPA believes that the facts and circumstances of each specific 
area will be relevant to whether the emissions reductions meet the 
agency's expectations for generally linear progress.\382\
---------------------------------------------------------------------------

    \382\ 81 FR 58010, 15386.
---------------------------------------------------------------------------

    The General Preamble Addendum also indicates that requiring 
generally linear progress may be less appropriate in other situations, 
such as:
     Where there are a limited number of sources of direct 
PM2.5 or a relevant precursor,
     where the relationships between individual sources and air 
quality are relatively well defined, and/or
     where the emission control systems utilized (e.g., at 
major point sources) will result in swift and dramatic emission 
reductions.
    In nonattainment areas characterized by any of these latter 
conditions, the EPA has recommended that RFP may be met by stepwise 
progress as controls are implemented and achieve significant reductions 
soon thereafter. For example, if an area's nonattainment problem can be 
attributed to a few major stationary sources, EPA guidance recommends 
that states may meet RFP by ``adherence to an ambitious compliance 
schedule'' that is likely to yield significant reductions of direct 
PM2.5 or a PM2.5 precursor on a periodic basis, 
rather than on a generally linear basis.\383\ The EPA believes that the 
facts and circumstances of each specific area will be relevant to 
whether the emissions reductions meet the agency's expectations for 
stepwise progress.
---------------------------------------------------------------------------

    \383\ Id.
---------------------------------------------------------------------------

    Plans for PM2.5 nonattainment areas should include 
detailed schedules for compliance with emission control measures in the 
area and provide corresponding annual emission reductions to be 
achieved by each milestone in the schedule.\384\ In reviewing an 
attainment plan under subpart 4, the EPA considers whether the annual 
incremental emissions reductions to be achieved are reasonable in light 
of the statutory objective of timely attainment. Although early

[[Page 17420]]

implementation of the most cost-effective control measures is often 
appropriate, states should consider both cost-effectiveness and 
pollution reduction effectiveness when developing implementation 
schedules for control measures, and may implement measures that are 
more effective at reducing PM2.5 earlier to provide greater 
public health benefits.\385\
---------------------------------------------------------------------------

    \384\ Id. at 42016.
    \385\ Id.
---------------------------------------------------------------------------

    In addition to the EPA's longstanding guidance on the RFP 
requirements, the Agency has established specific regulatory 
requirements in the PM2.5 SIP Requirements Rule for purposes 
of satisfying the Act's RFP requirements and provided related guidance 
in the preamble to the rule. Specifically, under the PM2.5 
SIP Requirements Rule, each PM2.5 attainment plan must 
contain an RFP analysis that includes, at minimum, the following four 
components: (1) An implementation schedule for control measures; (2) 
RFP projected emissions for direct PM2.5 and all 
PM2.5 plan precursors for each applicable milestone year, 
based on the anticipated control measure implementation schedule; (3) a 
demonstration that the control strategy and implementation schedule 
will achieve reasonable progress toward attainment between the base 
year and the attainment year; and (4) a demonstration that by the end 
of the calendar year for each triennial milestone date for the area, 
pollutant emissions will be at levels that reflect either generally 
linear progress or stepwise progress in reducing emissions on an annual 
basis between the base year and the attainment year.\386\
---------------------------------------------------------------------------

    \386\ 40 CFR 51.1012(a).
---------------------------------------------------------------------------

    A state intending to meet the RFP requirement on a stepwise basis 
must provide an appropriate justification for the selected 
implementation schedule.\387\ As the EPA explained in the preamble to 
the PM2.5 SIP Requirements Rule, a plan that relies on a 
stepwise approach to meeting RFP should include ``a clear rationale and 
supporting information to explain why generally linear progress is not 
appropriate (e.g., due to the nature of the nonattainment problem, the 
types of sources contributing to PM2.5 levels in the area 
and the implementation schedule for control requirements at such 
sources).'' \388\ Additionally, states should estimate the RFP 
projected emissions for each quantitative milestone year by sector on a 
pollutant-by-pollutant basis.\389\
---------------------------------------------------------------------------

    \387\ 40 CFR 51.1012(a)(4).
    \388\ 81 FR 58010, 58057.
    \389\ 81 FR 58010, 58056.
---------------------------------------------------------------------------

    Section 189(c) of the Act requires that PM2.5 attainment 
plans include quantitative milestones that demonstrate RFP. The purpose 
of the quantitative milestones is to allow periodic evaluation of the 
area's progress towards attainment of the PM2.5 NAAQS 
consistent with RFP requirements. Because RFP is an annual emission 
reduction requirement and the quantitative milestones are to be 
achieved every three years, when a state demonstrates compliance with 
the quantitative milestone requirement, it should also demonstrate that 
RFP has been achieved during each of the relevant three years. 
Quantitative milestones should provide an objective means to evaluate 
progress toward attainment meaningfully, e.g., through imposition of 
emissions controls in the attainment plan and the requirement to 
quantify those required emissions reductions. The CAA also requires a 
state to submit, within 90 days after each three-year quantitative 
milestone date, a milestone report that includes technical support 
sufficient to document completion statistics for appropriate 
milestones, e.g., the calculations and any assumptions made concerning 
emission reductions to date.\390\
---------------------------------------------------------------------------

    \390\ General Preamble Addendum, 42016, 42017.
---------------------------------------------------------------------------

    The CAA does not specify the starting point for counting the three-
year periods for quantitative milestones under CAA section 189(c). In 
the General Preamble and General Preamble Addendum, the EPA interpreted 
the CAA to require that the starting point for the first three-year 
period be the due date for the Moderate area plan submission.\391\ In 
keeping with this historical approach, the EPA established December 31, 
2014, the deadline that the EPA established for a state's submission of 
any additional attainment-related SIP elements necessary to satisfy the 
subpart 4 Moderate area requirements for the 2006 24-hour 
PM2.5 NAAQS, as the starting point for the first three-year 
period under CAA section 189(c) for the 2006 PM2.5 NAAQS in 
the San Joaquin Valley.\392\
---------------------------------------------------------------------------

    \391\ General Preamble, 13539, and General Preamble Addendum, 
42016.
    \392\ 79 FR 31566 (June 2, 2014) (final rule establishing 
subpart 4 moderate area classifications and deadline for related SIP 
submissions). Although this final rule did not affect any action 
that the EPA had previously taken under CAA section 110(k) on a SIP 
for a PM2.5 nonattainment area, the EPA noted that states 
may need to submit additional SIP elements to fully comply with the 
applicable requirements of subpart 4, even for areas with previously 
approved PM2.5 attainment plans, and that the deadline 
for any such additional plan submissions was December 31, 2014. Id. 
at 31569.
---------------------------------------------------------------------------

    Under the PM2.5 SIP Requirements Rule, each attainment 
plan submission for an area designated nonattainment for the 2006 
PM2.5 NAAQS before January 15, 2015, must contain 
quantitative milestones to be achieved no later than three years after 
December 31, 2014, and every three years thereafter until the milestone 
date that falls within three years after the applicable attainment 
date.\393\ If the area fails to attain, this post-attainment date 
milestone provides the EPA with the tools necessary to monitor the 
area's continued progress toward attainment while the state develops a 
new attainment plan under CAA section 189(d).\394\ Quantitative 
milestones must provide for objective evaluation of reasonable further 
progress toward timely attainment of the PM2.5 NAAQS in the 
area and include, at minimum, a metric for tracking progress achieved 
in implementing SIP control measures, including BACM and BACT, by each 
milestone date.\395\
---------------------------------------------------------------------------

    \393\ 40 CFR 51.1013(a)(4).
    \394\ 81 FR 58010, 58064.
    \395\ Id. at 58064 and 58092.
---------------------------------------------------------------------------

    Because the EPA designated the San Joaquin Valley as a 
nonattainment area for the 2006 24-hour PM2.5 NAAQS 
effective December 14, 2009,\396\ the plan for this area must contain 
quantitative milestones to be achieved no later than three years after 
December 31, 2014, and every three years thereafter until the milestone 
date that falls within three years after the applicable attainment 
date.\397\ The SJV PM2.5 Plan contains a request by the 
State under CAA section 188(e) to extend the applicable attainment date 
for the 2006 24-hour PM2.5 NAAQS in the San Joaquin Valley 
to December 31, 2024. Therefore, in accordance with 40 CFR 
51.1013(a)(4), the Serious area plan for this area must contain 
quantitative milestones to be achieved no later than December 31, 2017, 
December 31, 2020, December 31, 2023, and December 31, 2026.
---------------------------------------------------------------------------

    \396\ 74 FR 58688 (November 13, 2009).
    \397\ 40 CFR 51.1013(a)(4).
---------------------------------------------------------------------------

2. Summary of State's Submission
    Appendix H (``RFP, Quantitative Milestones, and Contingency'') of 
the 2018 PM2.5 Plan contains the State's RFP demonstration 
and quantitative milestones for the 2006 24-hour PM2.5 
NAAQS. Following the identification of a transcription error in the RFP 
tables of Appendix H, the State submitted a revised version of Appendix 
H that corrects the transcription error and provides additional 
information on the RFP demonstration.\398\ Given the State's

[[Page 17421]]

conclusions that ammonia, SOX, and VOC emissions do not 
contribute significantly to PM2.5 levels that exceed the 
2006 PM2.5 NAAQS in the San Joaquin Valley, as discussed in 
section IV.B of this preamble, the RFP demonstration provided by the 
State addresses emissions of direct PM2.5 and 
NOX.\399\ Similarly, the State developed quantitative 
milestones based upon the Plan's control strategy measures that achieve 
emission reductions of direct PM2.5 and NOX.\400\ 
For the 2006 PM2.5 NAAQS, the RFP demonstration in the Plan 
follows a stepwise approach due to the time required for CARB and the 
District ``to amend rules, develop programs, and implement the emission 
reduction measures.'' \401\ The revised Appendix H provides clarifying 
information on the RFP demonstration, including additional information 
to justify the Plan's stepwise approach to demonstrating RFP. This 
clarifying information did not affect the Plan's quantitative 
milestones.
---------------------------------------------------------------------------

    \398\ Appendix H to 2018 PM2.5 Plan, submitted 
February 11, 2020 via the EPA State Planning Electronic 
Collaboration System. This revised version of Appendix H replaces 
the version submitted with the 2018 PM2.5 Plan on May 10, 
2019. All references to Appendix H in this proposed rule are to the 
revised version of Appendix H submitted February 11, 2020.
    \399\ 2018 PM2.5 Plan, App. H, H-1.
    \400\ Id. at H-22 to H-23 (for State milestones) and H-19 to H-
20 (for District milestones).
    \401\ 2018 PM2.5 Plan, App. H, H-4.
---------------------------------------------------------------------------

    We describe the RFP demonstration and quantitative milestones in 
the SJV PM2.5 Plan in greater detail below.
a. Reasonable Further Progress
    The State addressed the RFP and quantitative milestone requirements 
in Appendix H to the 2018 PM2.5 Plan submitted in February 
2020. The Plan estimates that emissions of direct PM2.5 and 
NOX will generally decline from the 2013 base year to the 
projected 2024 attainment year, and beyond to the 2026 quantitative 
milestone year. The Plan's emissions inventory shows that direct 
PM2.5 and NOX are emitted by a large number and 
range of sources in the San Joaquin Valley. Table H-2 in Appendix H 
contains an anticipated implementation schedule for District regulatory 
control measures and Table 4-8 in Chapter 4 of the 2018 
PM2.5 Plan contains an anticipated implementation schedule 
for CARB control measures in the San Joaquin Valley. Table H-5 in 
Appendix H (reproduced in Table 10) contains projected emissions for 
each quantitative milestone year and the attainment year. These 
emission levels reflect both baseline emissions projections and 
commitments to achieve additional emission reductions through 
implementation of new control measures beginning in 2024.\402\
---------------------------------------------------------------------------

    \402\ In App. H, see Tables H-3 (emission projections based on 
baseline measures) and H-4 (reductions from control measure 
commitments). The SJV PM2.5 Plan includes commitments for 
reductions from new control measures in 2024 and 2025. With respect 
to the projected emission reductions for 2026, the District and CARB 
stated in a conversation with EPA staff on January 6, 2020 that they 
assumed reductions achieved in 2026 would be similar to reductions 
committed to in 2024 and 2025. See memorandum dated January 6, 2020, 
from Laura Lawrence, EPA Region IX Air Planning Office, to docket 
number EPA-R09-OAR-2019-0318.

       Table 10--PM2.5 Projected Emissions Inventory for Base and Milestone Years, Including Baseline Measures and Emission Reduction Commitments
                                                                  [Annual average tpd]
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                               2013            2017            2020            2023            2024            2026
                                                         -----------------------------------------------------------------------------------------------
                        Pollutant                                          Quantitative    Quantitative    Quantitative     Attainment     Quantitative
                                                           Baseline year     milestone       milestone       milestone         year          milestone
--------------------------------------------------------------------------------------------------------------------------------------------------------
PM2.5...................................................            62.5            58.9            59.0            58.3            56.1            56.2
NOX.....................................................           317.2           233.3           203.3           153.6           115.0           105.5
--------------------------------------------------------------------------------------------------------------------------------------------------------
Source: 2018 PM2.5 Plan, Appendix H, Table H-5.

    Table H-6 and Table H-7 of Appendix H (reproduced in Table 11) 
identify the reductions needed for attainment of the 2006 
PM2.5 NAAQS by 2024, and the San Joaquin Valley's progress 
toward attainment in each milestone year.

                                     Table 11--Reductions Needed for Attainment and Achieved in Each Milestone Year
                                                                    [Annual average]
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                           Percent reductions achieved in milestone year
                                                            Reductions   -------------------------------------------------------------------------------
                                                            needed for         2017            2020            2023            2024          2026 \a\
                        Pollutant                           attainment   -------------------------------------------------------------------------------
                                                            (from 2013     Quantitative    Quantitative    Quantitative                    Quantitative
                                                             baseline)       milestone       milestone       milestone      Attainment       milestone
                                                               (tpd)         (percent)       (percent)       (percent)    year (percent)     (percent)
--------------------------------------------------------------------------------------------------------------------------------------------------------
PM2.5...................................................             6.4            56.3            54.7            65.6             100            98.4
NOX.....................................................           202.2            41.5            56.3            81.0             100           104.7
--------------------------------------------------------------------------------------------------------------------------------------------------------
Source: 2018 PM2.5 Plan, Appendix H, Tables H-6 and H-7.
\a\ The EPA has made minor corrections to the calculated percentages for 2026 in Table H-7 of the 2018 PM2.5 Plan.

    Based on the data in Tables 10 and 11, the State and District set 
RFP targets for the attainment year and quantitative milestone years as 
shown in Table H-10 of Appendix H (reproduced in Table 12). The targets 
are consistent with a stepwise approach to demonstrating RFP. For 
direct PM2.5, significant reductions between the 2013 
baseline and the 2017 milestone year (approximately 56% of the 
reductions needed for attainment) are consistent with a generally 
linear approach to demonstrating RFP. However, between the 2017 and 
2020 milestone years, projected direct PM2.5 emissions 
increase. Emissions of direct PM2.5 decrease by the 2023 
milestone year but fall short of the rate of reductions that would show 
generally linear

[[Page 17422]]

progress.\403\ The Plan relies on a more substantial direct 
PM2.5 emission reduction in 2024 due, in large part, to the 
State's and District's commitments to achieve additional 
PM2.5 emission reductions from new measures in 2024. Direct 
PM2.5 emissions are projected to increase slightly in 2026.
---------------------------------------------------------------------------

    \403\ To show generally linear progress, direct PM2.5 
emissions would need to decrease by approximately 64% from the 
baseline year in 2020, and by approximately 91% from the baseline 
year in 2023. The actual decreases for these years are 55% in 2020, 
and 66% in 2023.
---------------------------------------------------------------------------

    For NOX, the emission projections show steady reductions 
over time. The projection for the 2017 milestone year is consistent 
with a generally linear RFP demonstration, but for the 2020 and 2023 
milestone years, emission reductions fall short of generally linear 
progress toward attainment.\404\ The Plan relies on a more substantial 
NOX emission reduction in 2024 due, in large part, to the 
State's and District's commitments to achieve additional NOX 
reductions from new measures that year. NOX emissions are 
projected to continue to decrease in the 2026 milestone year.
---------------------------------------------------------------------------

    \404\ To show generally linear progress, NOX 
emissions would need to decrease by approximately 64% from the 
baseline year in 2020, and by approximately 91% from the baseline 
year in 2023. The actual decreases for these years are 56% in 2020, 
and 81% in 2023.
---------------------------------------------------------------------------

    According to the Plan, reductions in both direct PM2.5 
and NOX emissions from 2013 base year levels result in 
emissions levels consistent with attainment in the 2024 attainment 
year. Based on these analyses, the State and District conclude that the 
adopted control strategy and additional commitments for reductions from 
new control programs beginning in 2024 are adequate to meet the RFP 
requirement for the 2006 PM2.5 NAAQS.

                                         Table 12--Stepwise RFP Target Emission Levels and Projected Emission Levels for Milestone and Attainment Years
                                                                                      [Annual average tpd]
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                          2017                      2020                      2023                    2024 \a\                    2026
                           Pollutant                           ---------------------------------------------------------------------------------------------------------------------------------
                                                                   Target     Projected      Target     Projected      Target     Projected      Target     Projected    Target \b\   Projected
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
PM2.5.........................................................         58.9         58.9         59.0         59.0         58.3         58.3         56.1         56.1         56.2         56.2
NOX...........................................................        233.3        233.3        203.3        203.3        153.6        153.6        115.0        115.0        105.5        105.5
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Source: 2018 PM2.5 Plan, Appendix H, Tables H-6 and H-10.
\a\ Emissions targets and projections for the 2024 attainment year are provided in Table H-6 of the 2018 PM2.5 Plan.
\b\ Direct PM2.5 emissions for 2026 are derived from the Plan's projected emissions inventory (including baseline controls), less the 2.2 tpd of direct PM2.5 emissions that CARB and the
  District committed to achieve by 2024. 2018 PM2.5 Plan, Appendix H, Tables H-3, H-4, and H-5.

    The State and District's control strategy for attaining the 2006 
PM2.5 NAAQS relies primarily on ongoing reductions from 
baseline measures, recent revisions to the District's residential wood 
burning rule (Rule 4901), and an aggregate tonnage commitment for the 
remaining reductions needed for attainment. The majority of the 
NOX and PM2.5 reductions needed for attainment 
result from CARB's current mobile source control program. As shown in 
Table 11, the attainment control strategy in the Plan is projected to 
achieve a total of 202.2 tpd of NOX reductions by 2024, of 
which 78% (157 tpd) is attributed to CARB's mobile source control 
program.\405\ Similarly, the attainment control strategy is projected 
to achieve a total of 6.4 tpd of direct PM2.5 reductions by 
2024, of which 72% (4.6 tpd) is attributed to CARB's mobile source 
control program.\406\ These on-going controls will thus result in 
additional reductions in NOX and direct PM2.5 
emissions between the base year (2013) and the attainment year 
(2024).\407\
---------------------------------------------------------------------------

    \405\ Id. at Chapter 4, Table 4-7.
    \406\ Id.
    \407\ Id. at App. H, H-4.
---------------------------------------------------------------------------

    CARB's mobile source control program provides significant ongoing 
reductions in emissions of direct PM2.5 and NOX 
from on-road and non-road mobile sources such as light duty vehicles, 
heavy-duty trucks and buses, non-road equipment, and fuels. For on-road 
and non-road mobile sources, which represent the largest sources of 
NOX emissions in the San Joaquin Valley, Appendix H of the 
2018 PM2.5 Plan identifies five mobile source regulations 
and control programs that limit emissions of direct PM2.5 
and NOX: The On-Road Heavy-Duty Diesel Vehicles (In-Use) 
Regulation (``Truck and Bus Regulation''), the Advanced Clean Cars 
Program (``ACC Program''), the In-Use Off-Road Diesel-Fueled Fleets 
Regulation (``Off-Road Regulation''), the Heavy-Duty Vehicle Inspection 
and Maintenance Program, and the California Low-NOX Engine 
Standard for new on-road heavy-duty engines used in medium- and heavy-
duty trucks purchased in California.\408\ CARB's mobile source BACM and 
MSM analysis in Appendix D of the 2018 PM2.5 Plan provides a 
more comprehensive overview of each of these programs and regulations, 
among many others.\409\ CARB's emission projections for mobile sources 
are presented in the Plan's emissions inventory.\410\
---------------------------------------------------------------------------

    \408\ 2018 PM2.5 Plan, App. H, H-21 and H-22. Because 
the second phase of the Advanced Clean Cars Program (``ACC 2'') is 
not scheduled for implementation until 2026 (see 2018 
PM2.5 Plan, Table 4-8), which is after the January 1, 
2024 implementation deadline under 40 CFR 51.1011(b)(5) for control 
measures necessary for attainment by December 31, 2024, we are not 
reviewing this program as part of the control strategy in the SJV 
PM2.5 Plan.
    \409\ 2018 PM2.5 Plan, App. D, Ch. IV.
    \410\ 2018 PM2.5 Plan, App. B.
---------------------------------------------------------------------------

    The Truck and Bus Regulation, first adopted in 2008 and amended in 
2011, has rolling compliance deadlines based on truck engine model year 
(MY). CARB's implementation of the Truck and Bus Regulation includes 
phase-in requirements for PM2.5 and NOX emissions 
reductions that began in 2012 and require nearly all pre-2010 vehicles 
to have exhaust emissions meeting 2010 MY engine emission levels by 
2023.\411\ The 2010 MY engines include particulate filters for direct 
PM2.5 control. By 2016, the particulate filter requirement 
for trucks with a gross vehicle weight rating greater than 26,001 
pounds was fully implemented in the San Joaquin Valley and all heavier 
trucks with 1995 and older model year engines were required to have a 
2010 engine installed or replaced by a truck with a 2010 MY 
engine.\412\
---------------------------------------------------------------------------

    \411\ The State's quantitative milestone report for the 2017 
milestone indicates that the requirement for heavier trucks to 
install diesel particulate filters was fully implemented by 2016. 
CARB and SJVUAPCD, ``2017 Quantitative Milestone Report for the 1997 
and 2006 NAAQS,'' November 21, 2018 (``2017 QM Report''), 5.
    \412\ Id.
---------------------------------------------------------------------------

    For non-road vehicles, CARB adopted the Off-Road Regulation in 2007 
to regulate vehicles used in construction, mining, and other industrial 
applications. The Off-Road Regulation requires owners to (1) replace 
older

[[Page 17423]]

engines or vehicles with newer, cleaner models, (2) retire older 
vehicles or reduce their use, or (3) apply retrofit exhaust 
controls.\413\ Beginning in 2014 for large fleets and in 2017 for 
medium fleets, non-road fleets are required to meet increasingly 
stringent fleet average indices over time.\414\ These indices reflect a 
fleet's overall PM and NOX emissions rates by model year and 
horsepower.
---------------------------------------------------------------------------

    \413\ 2017 QM Report, 8.
    \414\ A fleet average index is an indicator of a fleet's overall 
emissions rate of particulate matter and NOX based on the 
horsepower and model year of each engine in the fleet.
---------------------------------------------------------------------------

    The District has also adopted numerous stationary and area source 
rules for direct PM2.5 and NOX emission sources 
that are projected to contribute to RFP and attainment of the 
PM2.5 standards. These include control measures for 
stationary internal combustion engines, residential fireplaces, glass 
manufacturing facilities, agricultural burning sources, and various 
sizes of boilers, steam generators, and process heaters used in 
industrial operations. Appendix H of the 2018 PM2.5 Plan 
identifies stationary source regulatory control measures implemented by 
the District that achieve ongoing PM2.5 and/or 
NOX reductions through the Plan's RFP milestone years and 
the attainment year, including the following: Rule 4354 (``Glass 
Melting Furnaces''), Rule 4702 (Internal Combustion Engines''), and 
Rule 4901 (``Wood Burning Fireplaces and Wood Burning Heaters'').\415\
---------------------------------------------------------------------------

    \415\ 2018 PM2.5 Plan, App. H, Table H-2.
---------------------------------------------------------------------------

    Rule 4354 was last amended in 2011 to lower certain limits on 
emissions of NOX, SOX, and PM10 from 
container glass, flat glass, and fiberglass manufacturing facilities. 
Rule 4702 was last amended in 2013 to lower the NOX and 
SOX emission limits for various types of internal combustion 
engines rated at 25 brake horsepower or greater. The District most 
recently amended Rule 4901 in 2019 to lower the thresholds at which 
``No Burn'' days will be imposed to limit direct PM2.5 
emissions from high-polluting wood burning heaters and fireplaces 
during the November through February timeframe in three ``hot spot'' 
counties (Fresno, Kern, and Madera). These rules contribute to 
incremental reductions in emission of direct PM2.5 and 
NOX from the 2013 base year to the 2017 and 2020 RFP 
milestone years.\416\ Additional District measures to control sources 
of direct PM2.5 and NOX are also presented in the 
Plan's BACM/MSM analyses and reflected in the Plan's baseline emission 
projections.\417\
---------------------------------------------------------------------------

    \416\ 2017 QM Report, 2-3.
    \417\ 2018 PM2.5 Plan, App. B and App. C.
---------------------------------------------------------------------------

    For the remainder of the emission reductions necessary for 
attainment, the SJV PM2.5 Plan identifies a series of 
additional State and District commitments to achieve emission 
reductions through additional control measures and incentive programs 
that will contribute to attainment of the 2006 PM2.5 NAAQS 
by 2024. For mobile sources, CARB's commitment identifies a list of 12 
regulatory measures and three incentive-based measures that CARB has 
committed to propose to its Board for consideration by specific 
dates.\418\ For stationary and area sources, the District's commitment 
identifies a list of nine regulatory measures and three incentive-based 
measures that the District has committed to propose to its Board for 
consideration by specific dates.\419\ Both CARB and the District have 
committed to achieve specific amounts of reductions in direct 
PM2.5 and NOX emissions by 2024, either through 
implementation of these listed measures or through implementation of 
other control measures that achieve the necessary amounts of emission 
reductions by 2024.\420\
---------------------------------------------------------------------------

    \418\ 2018 PM2.5 Plan, Chapter 4, Table 4-8 and CARB 
Resolution 18-49 (October 25, 2018), 5. Table 4-8 of the 2018 
PM2.5 Plan lists 14 State regulatory measures but we are 
excluding from our review the ``Advanced Clean Cars 2'' measure and 
the ``Cleaner In-Use Agricultural Equipment'' measure, because these 
measures are scheduled for implementation in 2026 and 2030, 
respectively, well after the January 1, 2024 implementation deadline 
for control measures necessary for attainment by December 31, 2024. 
40 CFR 51.1011(b)(5).
    \419\ 2018 PM2.5 Plan, Chapter 4, Table 4-4 and 
SJVUAPCD Governing Board Resolution 18-11-16 (November 15, 2018), 
10-11.
    \420\ SJVUAPCD Governing Board Resolution 18-11-16 (November 15, 
2018), 10-11 and CARB Resolution 18-49 (October 25, 2018), 5.
---------------------------------------------------------------------------

    The 2018 PM2.5 Plan discusses a number of additional 
control measures that the District may adopt to meet its aggregate 
tonnage commitment, including additional control requirements for 
flares; boilers, steam generators, and process heaters of various 
sizes; glass melting furnaces; internal combustion engines; 
conservation management practices for agricultural operations; and 
commercial under-fired charbroilers.\421\ In addition, the Plan states 
that the District intends to use incentive programs to reduce emissions 
of direct PM2.5 and NOX from internal combustion 
engines used in agricultural operations, commercial under-fired 
charbroilers, and residential woodburning devices.\422\ The 2018 
PM2.5 Plan establishes deadlines between 2018 and 2023 for 
CARB to take action on and begin implementing the 15 additional mobile 
source control measures that CARB has committed to propose to its Board 
\423\ and similar deadlines between 2019 and 2024 for the District to 
take action on and begin implementing the 12 additional District 
control measures that the District has committed to propose to its 
Board.\424\
---------------------------------------------------------------------------

    \421\ 2018 PM2.5 Plan, Chapter 4, 4-12 and 4-15 to 4-
22.
    \422\ Id. at 4-22 to 4-24.
    \423\ 2018 PM2.5 Plan, Chapter 4, Table 4-8 and CARB 
Resolution 18-49 (October 25, 2018), 5. The EPA is excluding two 
State measures listed in Table 4-8 of the 2018 PM2.5 
Plan, the ``Advanced Clean Cars 2'' measure and the ``Cleaner In-Use 
Agricultural Equipment'' measure, because these measures are 
scheduled for implementation in 2026 and 2030, respectively, well 
after the January 1, 2024 implementation deadline for control 
measures necessary for attainment by December 31, 2024. 40 CFR 
51.1011(b)(5).
    \424\ 2018 PM2.5 Plan, Table 4-4 and Table 4-5 and 
SJVUAPCD Governing Board Resolution 18-11-16 (November 15, 2018), 
10-11.
---------------------------------------------------------------------------

    The anticipated implementation schedule for new District measures 
is presented both in Table H-2 of Appendix H and in tables 4-4 and 4-5 
of the 2018 PM2.5 Plan, and the anticipated implementation 
schedule for new CARB measures is presented in Table 4-8 of the 2018 
PM2.5 Plan. These anticipated implementation schedules are 
summarized in Table 13, below. Although the commitment to achieve 
reductions is based on an aggregate commitment for total reductions in 
2024, the State and District anticipate implementing many of the 
measures in Table 13 prior to these dates to achieve the aggregate 
tonnage commitment.
    Specifically, implementation of the District's revisions to Rule 
4901 (``Wood Burning Fireplaces and Wood Burning Heaters'') began in 
2019, and implementation of CARB's lower opacity limits for heavy-duty 
vehicles began in 2018. Additionally, the District anticipates 
implementing several measures beginning in 2023 and CARB anticipates 
implementing several measures in 2020, 2022, and 2023.\425\
---------------------------------------------------------------------------

    \425\ For more detail on our evaluation of the State's and 
District's aggregate commitments, see section IV.D.4.b.ii of this 
preamble.

[[Page 17424]]



  Table 13--Anticipated Implementation Schedule for State and District
                                Measures
------------------------------------------------------------------------
             CARB measures                   Implementation  begins
------------------------------------------------------------------------
Lower In-Use Emission Performance
 Level:
    Lower Opacity Limits for Heavy-     2018-2024.
     Duty Vehicles.
    Amended Warranty Requirements for   2022.
     Heavy-Duty Vehicles.
    Heavy-Duty Vehicle Inspection and   2022.
     Maintenance Program.
Low-NOX Engine Standard...............  2023.
Innovative Clean Transit..............  2020.
Advanced Clean Local Trucks (Last Mile  2020.
 Delivery).
Zero-Emission Airport Shuttle Buses...  2023.
Zero-Emission Off-Road Forklift         2023.
 Regulation Phase 1.
Zero-Emission Airport Ground Support    2023.
 Equipment.
Small Off-Road Engines................  2022.
Transport Refrigeration Units Used for  2020.
 Cold Storage.
Low-Emission Diesel Fuel Requirement..  2023.
Accelerated Turnover of Trucks and      Ongoing.
 Buses.
Accelerated Turnover of Agricultural    Ongoing.
 Equipment.
Accelerated Turnover of Off-Road        Ongoing.
 Equipment.
------------------------------------------------------------------------


 
           District measures                 Implementation  begins
------------------------------------------------------------------------
Rule 4311 (``Flares'')................  2023.
Rule 4306 (``Boilers, Steam             2023.
 Generators, and Process Heaters--
 Phase 3''), Rule 4320 (``Advanced
 Emission Reduction Options for
 Boilers, Steam Generators, and
 Process Heaters Greater than 5.0
 MMBtu/hr'').
Rule 4702 (``Internal Combustion        2024.
 Engines'').
Rule 4354 (``Glass Melting Furnaces'')  2023.
Rule 4352 (``Solid Fuel-Fired Boilers,  2023.
 Steam Generators and Process
 Heaters'').
Rule 4550 (``Conservation Management    2024.
 Practices'').
Rule 4692 (``Commercial                 2024.
 Charbroiling'') (Hot-spot Strategy).
Rule 4901 (``Wood Burning Fireplaces    2019.
 and Wood Burning Heaters'') (Hot-spot
 Strategy).
Replacement of Internal Combustion      Ongoing.
 Engines used at Agricultural
 Operations.
Installation of Commercial Under-fired  Ongoing.
 Charbroiling Controls (Hot-spot
 Strategy).
Replacement of Residential Wood         Ongoing.
 Burning Devices (Valley-wide and Hot-
 spot Strategy).
------------------------------------------------------------------------
Source: 2018 PM2.5 Plan, Table 4-4, Table 4-5, Table 4-8 and Appendix H,
  Table H-2.

    Section H.1.3 of Appendix H of the Plan provides the State's and 
District's justifications for the stepwise approach to meeting the RFP 
requirement and the related implementation schedules for new or revised 
control measures. These justifications include the time needed to 
engage in the rulemaking process, including time for state and local 
public processes; the need to provide time for industry to comply with 
new regulatory requirements; the need to resolve feasibility issues for 
emerging technologies; and, for CARB mobile source measures, the need 
for affected industries to prepare technologies and infrastructure for 
market-scale adoption.
    For example, Appendix H of the 2018 PM2.5 Plan states 
that ``time after rule adoption will be necessary for unit 
manufacturers and vendors to make available compliant equipment, and 
for facility operators to source, purchase, and install new units or 
compliant retrofit equipment. Dependent on the source category, 
construction of controls will include engineering, site preparation and 
infrastructure upgrades, unit installation, and operator training on 
proper operation.'' \426\
---------------------------------------------------------------------------

    \426\ 2018 PM2.5 Plan, App. H, H-7.
---------------------------------------------------------------------------

    We present below some of the implementation challenges that the 
State and District have identified as part of their justification for 
meeting the RFP requirement by the stepwise approach in the Plan.
    The new NOX control measures that CARB and the District 
anticipate implementing toward the end of the attainment period can be 
found in Table 4-4, Table 4-5, and Table 4-8 of the 2018 
PM2.5 Plan. Appendix H of the 2018 PM2.5 Plan 
provides the following explanation for the need to implement the listed 
measures in a stepwise manner:
    ``The objective of many of CARB's new measures is to introduce or 
advance innovative technologies in early stages of development or 
market penetration. In the case of technology-forcing regulations, . . 
. time is needed by the affected industry to ready the technologies, 
including infrastructure, for market-scale adoption, and would have 
been discussed previously by CARB and stakeholders during the measure 
development phase. The time required to facilitate new and innovative 
technologies is a principle driver of the timeline for control measure 
implementation CARB laid out in Table 4-8.'' \427\
---------------------------------------------------------------------------

    \427\ 2018 PM2.5 Plan, App. H, H-8.
---------------------------------------------------------------------------

    CARB provided more specific information regarding two of these 
measures on pages H-9 and H-10 of Appendix H. For instance, the 
development of the Heavy-Duty Vehicle Inspection and Maintenance 
Program was affirmed by California legislative action in 2019, and CARB 
is now working on program design and infrastructure to implement new 
legislative direction.\428\ For the Low-NOX Engine Standard, 
the implementation timeline has been influenced by a multi-year 
research program to assess the feasibility of this standard.
---------------------------------------------------------------------------

    \428\ California Senate Bill 210, signed September 20, 2019.
---------------------------------------------------------------------------

    The new direct PM2.5 measures that CARB and the District 
anticipate implementing toward the end of the attainment period can be 
found in Table 4-4, Table 4-5, and Table 4-8 of the 2018 
PM2.5 Plan. CARB's additional measures are expected to 
achieve 0.9 tpd of direct PM2.5 emission reductions \429\ 
and the District's

[[Page 17425]]

additional measures, including revised rules for commercial 
charbroiling and conservation management practices (CMPs) for 
agricultural operations, are expected to achieve 1.3 tpd of direct 
PM2.5 emission reductions in 2024.\430\ New or revised 
District measures are thus expected to achieve a significant portion of 
the State's and District's 2.2 tpd direct PM2.5 emission 
reduction commitment for the 2024 attainment year.
---------------------------------------------------------------------------

    \429\ 2018 PM2.5 Plan, Table 4-9.
    \430\ Id. at Table 4-3.
---------------------------------------------------------------------------

    For example, the 2018 PM2.5 Plan shows that 
approximately one fourth of the direct PM2.5 emission 
reductions that the State and District have committed to achieve by 
2024 (0.53 of 2.2 tpd) are expected to result from a planned revision 
to the District's commercial charbroiling rule (Rule 4692) that would 
contain control requirements for under-fired charbroilers (UFCs).\431\ 
The District anticipates proposing this revised rule to the SJVUAPCD 
Governing Board in 2020 and implementing it beginning in 2024.\432\ 
According to information provided in Appendix C of the 2018 
PM2.5 Plan, the costs associated with retrofitting control 
technology onto equipment at existing restaurants and maintaining such 
equipment can be prohibitively expensive, especially for smaller 
restaurants.\433\ Because of ongoing uncertainties about the 
technological and economic feasibility of controls for UFCs, the 
District has adopted a set of registration and reporting provisions in 
a revised version of Rule 4692 that required owners and operators of 
commercial cooking operations with UFCs to register each unit and to 
submit, by January 1, 2019, a one-time informational report providing 
information about the UFC and its operations. CARB submitted this 
revised rule to the EPA on November 16, 2018.
---------------------------------------------------------------------------

    \431\ Id. at 4-19, 4-2 and Table 4-3.
    \432\ Id. at Table 4-4.
    \433\ Id. at C-209 to C-210.
---------------------------------------------------------------------------

    The 2018 PM2.5 Plan also shows that a portion of the 
necessary direct PM2.5 emission reductions in 2024 (0.32 of 
2.2 tpd) is expected to result from a revised version of the District's 
CMP rule (Rule 4550), which is designed to reduce particulate emissions 
from agricultural operations.\434\ The District anticipates proposing 
this revised rule to the SJVUAPCD Governing Board in 2022 and 
implementing it beginning in 2024.\435\ As explained in Appendix C of 
the 2018 PM2.5 Plan, an important step in developing 
effective PM2.5 controls for dust from agricultural 
operations is to develop an understanding of the effectiveness of CMPs 
on controlling PM2.5 emissions in the Valley.'' \436\ 
Towards this end, the District intends to work with stakeholders and 
researchers to evaluate the feasibility and effectiveness of additional 
control measures to reduce PM2.5 emissions, including: 
Tilling and other land preparation activities; selection of 
conservation tillage as a CMP for croplands; and CMPs on fallow lands 
that are tilled or otherwise worked with implements of husbandry (e.g., 
a farm tractor drawing a trailer with crops) to reduce windblown PM 
emissions from disturbed fallowed acreage.\437\
---------------------------------------------------------------------------

    \434\ Id. at Table 4-3.
    \435\ Id. at Table 4-4.
    \436\ The District is holding a series of workshops from January 
to March 2020 with the stated goal of ``assisting growers and dairy 
families in understanding and complying with District Rule 4550.'' 
SJVUAPCD, ``Notice of Public Hearing for Adoption of Proposed 2018 
PM2.5 Plan for the 1997, 2006, and 2012 Standards,'' 
available at https://www.valleyair.org/Workshops/postings/2020/2020_CMP/notice.pdf.
    \437\ Id. at C-203.
---------------------------------------------------------------------------

b. Quantitative Milestones
    Appendix H of the 2018 PM2.5 Plan identifies December 31 
milestone dates for the 2017, 2020, and 2023 milestone years and for 
the 2026 post-attainment milestone year.\438\ Appendix H also 
identifies target emissions levels to meet the RFP requirement for 
direct PM2.5 and NOX emissions for each of these 
milestone years,\439\ as shown in Table 10, above, and control measures 
that the State or District plan to implement by each of these years, in 
accordance with the control strategy in the Plan.\440\
---------------------------------------------------------------------------

    \438\ 2018 PM2.5 Plan, App. H, Table H-12.
    \439\ Id. at Table H-5.
    \440\ Id. at H-22 to H-23 (for State milestones) and H-19 to H-
20 (for District milestones).
---------------------------------------------------------------------------

    The Plan includes quantitative milestones for mobile, stationary, 
and area sources. For mobile sources, the State has developed 
quantitative milestones that provide for evaluation of RFP based on the 
implementation of specific control measures by the relevant three-year 
milestones. For the first three quantitative milestones, the Plan 
provides for evaluating RFP with implementation of regulatory measures; 
for the final post attainment date quantitative milestone in 2026, the 
Plan provides for evaluating RFP with implementation of incentive 
measures.\441\ For the 2017, 2020, and 2023 milestone years, the 
quantitative milestones include implementation of the Truck and Bus 
Regulation, which requires particulate filters and cleaner engines on 
existing trucks and buses, in the years preceding each milestone year 
(i.e., between 2012-2017, 2017-2020, and 2020-2023, respectively). Each 
of these milestone years also includes action on or implementation of 
certain State measures for light-duty vehicles and non-road vehicles as 
follows:
---------------------------------------------------------------------------

    \441\ Id. at H-22 to H-23.
---------------------------------------------------------------------------

     2017--Truck and Bus Regulation, ACC Program, and Off-Road 
Regulation;
     2020--Truck and Bus Regulation, ACC 2: Reduced ZEV Brake 
and Tire Wear, and Heavy-Duty Vehicle Inspection and Maintenance 
Program; and
     2023--Truck and Bus Regulation and the California Low-
NOX Engine Standard for new on-road heavy-duty engines in 
medium- and heavy-duty trucks bought in California.
    For 2026, the Plan's quantitative milestone includes an update on 
the State's implementation of two incentive programs, specifically, 
identification of the number of trucks and buses turned over to low-
NOX or cleaner engines due to the State's Accelerated 
Turnover of Trucks and Buses Measure, and identification of the number 
of pieces of agricultural equipment replaced with Tier 4 engines due to 
the State's Accelerated Turnover of Agricultural Equipment 
Measure.\442\
---------------------------------------------------------------------------

    \442\ 2018 PM2.5 Plan, App. H, H-22.
---------------------------------------------------------------------------

    For stationary and area sources, the District has developed 
quantitative milestones that similarly include updates on a combination 
of regulatory measures and incentive measures. For 2017, the District's 
quantitative milestones are to report on its implementation of six 
District measures: 2014 amendments to Rule 4901 (``Wood Burning 
Fireplaces and Wood Burning Heaters'') and certain incentive programs 
for direct PM2.5, Rule 4308 (``Boilers, Steam Generators, 
and Process Heaters (0.075 to <2 MMBtu)''), 2011 amendments to Rule 
4354 (``Glass Melting Furnaces''), 2013 amendments to Rule 4702 
(``Internal Combustion Engines''), Rule 4902 (``Residential Water 
Heaters''), and Rule 4905 (``Natural Gas-fired, Fan-type, Residential 
Central Furnaces'').\443\
---------------------------------------------------------------------------

    \443\ Id. at H-19.
---------------------------------------------------------------------------

    For the 2020, 2023, and 2026 milestone years, the District's 
quantitative milestones are to report on the status of measures 
proposed and/or adopted during the preceding three years according to 
the schedule in the Plan.\444\ Consistent with the State and District's 
control strategy in Chapter 4 of the 2018 PM2.5 Plan, the 
District's quantitative milestones include updates on the status of the 
District's residential wood burning strategy (both the 2019 amendments 
to Rule 4901 and incentive

[[Page 17426]]

projects for residential wood burning devices), the District's 
incentive-based strategy for commercial under-fired charbroilers, and 
the regulatory measures scheduled for SJVUAPCD Board consideration 
during the three years preceding the following milestone years:
---------------------------------------------------------------------------

    \444\ Id. at H-19 to H-20.
---------------------------------------------------------------------------

     2020--Rule 4311 (``Flares), Rules 4306/4320 (large 
boilers, steam generators, and process heaters), Rule 4702 (``Internal 
Combustion Engines''), and Rule 4692 (``Commercial Under-fired 
Charbroilers''); and
     2023--Rules 4354 (``Glass Melting Furnaces''), 4352 
(``Solid Fuel-Fired Boilers, Steam Generators and Process Heaters''), 
and Rule 4550 (``Conservation Management Practices'').\445\
---------------------------------------------------------------------------

    \445\ 2018 PM2.5 Plan, Ch. 4, Tables 4-4 and 4-5.
---------------------------------------------------------------------------

    We note that CARB submitted its 2017 Quantitative Milestone Report 
to the EPA on December 20, 2018.\446\ This report includes a 
certification that CARB and the District met the 2017 quantitative 
milestones for the San Joaquin Valley for the 2006 PM2.5 
NAAQS and discusses the State's and District's progress on implementing 
the three CARB measures and six District measures identified in 
Appendix H as quantitative milestones for the 2017 milestone year.
---------------------------------------------------------------------------

    \446\ Letter from Richard W. Corey, Executive Officer, CARB, to 
Michael Stoker, Regional Administrator, EPA Region IX, with 
attachment, December 20, 2018.
---------------------------------------------------------------------------

3. EPA's Evaluation and Proposed Action
a. Reasonable Further Progress
    We have evaluated the RFP demonstration in Appendix H of the 2018 
PM2.5 Plan and, for the following reasons, propose to find 
that it satisfies the statutory and regulatory requirements for RFP. 
First, the Plan contains an anticipated implementation schedule for the 
attainment control strategy, including all BACM, BACT, and MSM control 
measures and the State's and District's aggregate tonnage commitments, 
as required by 40 CFR 51.1012(a)(1). The implementation schedule is 
found in Table 4-4, Table 4-5, and Table 4-8 of the 2018 
PM2.5 Plan and in Table H-2 of Appendix H. The 2018 
PM2.5 Plan documents the State's and District's conclusion 
that they are implementing all BACM, BACT, and MSM for direct 
PM2.5 and NOX emissions in the Valley as 
expeditiously as practicable.\447\
---------------------------------------------------------------------------

    \447\ The BACM/BACT and MSM control strategy that provides the 
basis for these emissions projections is described in Chapter 4, 
App. C, and App. D of the 2018 PM2.5 Plan.
---------------------------------------------------------------------------

    Second, the RFP demonstration contains projected emission levels 
for direct PM2.5 and NOX for each applicable 
milestone year as required by 40 CFR 51.1012(a)(2). These projections 
are based on continued implementation of the existing control measures 
in the area (i.e., baseline measures), recent revisions to the 
District's residential wood burning rule (Rule 4901), and commitments 
to achieve additional reductions from new measures in 2024, and reflect 
full implementation of the State's, District's, and MPOs' attainment 
control strategy for these pollutants. With regard to the 2026 
milestone year, we note that the projection is based on reductions from 
baseline measures and on an assumption that the amount of reductions 
from new control measures that will be achieved in 2026 is the same as 
those achieved in 2024 and 2025.
    Third, the projected emissions levels based on the implementation 
schedule in the Plan demonstrate that the control strategy will achieve 
reasonable further progress toward attainment between the 2013 baseline 
year and the 2024 attainment year as required by 40 CFR 51.1012(a)(3). 
Tables 11 and 12 of this proposed rule show decreases in emissions 
levels in each milestone year, leading to the achievement of the 
reductions required for attainment in 2024. Although the direct 
PM2.5 emissions increase slightly (0.1 tpd) over attainment 
year levels in the 2026 post-attainment milestone year, we expect that 
this small emissions increase will have de minimis impacts on the 
area's attainment and maintenance of the NAAQS.
    Finally, the RFP demonstration shows that overall pollutant 
emissions will be at levels that reflect stepwise progress between the 
base year and the attainment year and provides a justification for the 
selected implementation schedule, as required by 40 CFR 51.1012(a)(4). 
The steeper decline in emissions in 2024 is primarily due to a 
commitment by the State and District to achieve reductions from new 
control measures beginning in 2024. The State's and District's 
justifications for their selected implementation schedules, i.e., for 
the delay to 2024 in their respective commitments to achieve emissions 
reductions from new or revised control measures, include the time 
needed for rulemaking processes, the time needed for industry to comply 
with new regulatory requirements, the need to resolve feasibility 
issues for emerging technologies, and the time needed to prepare 
technologies and infrastructure for market-scale adoption.
    We note that although both the State and District have committed to 
propose to their respective boards certain new or revised control 
measures in the years leading up to the 2024 attainment year, the only 
enforceable commitment in the Plan that requires adoption of control 
measures is the tonnage commitment for 2024, which provides the basis 
for the stepwise approach to RFP. Because of the size of the tonnage 
commitments for the 2024 attainment year, and the absence of 
commitments to adopt measures or achieve emission reductions in earlier 
years, we request comment on whether additional enforceable commitments 
for regulatory action to implement emission controls in the interim 
years (i.e., in 2022 or 2023) are necessary to ensure that the stepwise 
approach to emission reductions in the Plan is consistent with 
reasonable further progress toward expeditious attainment. Such 
commitments may include commitments to achieve specified amounts of 
emission reductions before 2024 (i.e., aggregate tonnage commitments) 
or commitments to adopt specific new or revised control measures by 
specific dates before 2024, and may provide a basis for reducing the 
size of the total tonnage commitment for the 2024 attainment year.
b. Quantitative Milestones
    Appendix H of the 2018 PM2.5 Plan identifies milestone 
dates (i.e., December 31 of 2017, 2020, 2023, and 2026) that are 
consistent with the requirements of 40 CFR 51.1013(a)(4) and target 
emissions levels for direct PM2.5 and NOX to be 
achieved by these milestone dates through implementation of the Plan's 
control strategy. These target emission levels and associated control 
requirements provide for objective evaluation of the area's progress 
towards attainment of the 2006 24-hour PM2.5 NAAQS.
    The State's quantitative milestones in Appendix H are to take 
action on or to implement specific measures listed in the State's 
control measure commitments that apply to heavy-duty trucks and buses, 
light-duty vehicles, and non-road equipment sources and may provide 
substantial reductions in emissions of direct PM2.5 and 
NOX from mobile sources in the San Joaquin Valley. 
Similarly, the District's quantitative milestones in Appendix H are to 
take action on or to implement specific measures listed in the 
District's control measure commitments that apply to sources such as 
residential wood burning, commercial charbroiling, conservation 
management practices,

[[Page 17427]]

glass melting furnaces, and internal combustion engines and that may 
provide substantial reductions in emission of direct PM2.5 
and NOX from stationary sources. These milestones provide an 
objective means for tracking the State's and District's progress in 
implementing their respective control measure and aggregate tonnage 
commitments and, thus, provide for objective evaluation of the San 
Joaquin Valley's progress toward timely attainment.
    For these reasons, we propose to determine that the SJV 
PM2.5 Plan satisfies the requirements for quantitative 
milestones in CAA section 189(c) and 40 CFR 51.1013 for the 2006 
PM2.5 NAAQS in the San Joaquin Valley.

F. Motor Vehicle Emission Budgets

1. Statutory and Regulatory Requirements
    Section 176(c) of the CAA requires federal actions in nonattainment 
and maintenance areas to conform to the SIP's goals of eliminating or 
reducing the severity and number of violations of the NAAQS and 
achieving expeditious attainment of the standards. Conformity to the 
SIP's goals means that such actions will not: (1) Cause or contribute 
to violations of a NAAQS, (2) worsen the severity of an existing 
violation, or (3) delay timely attainment of any NAAQS or any interim 
milestone.
    Actions involving Federal Highway Administration (FHWA) or Federal 
Transit Administration (FTA) funding or approval are subject to the 
EPA's transportation conformity rule, codified at 40 CFR part 93, 
subpart A (``Transportation Conformity Rule''). Under this rule, 
metropolitan planning organizations (MPOs) in nonattainment and 
maintenance areas coordinate with state and local air quality and 
transportation agencies, EPA, FHWA, and FTA to demonstrate that an 
area's regional transportation plans (RTP) and transportation 
improvement programs (TIP) conform to the applicable SIP. This 
demonstration is typically done by showing that estimated emissions 
from existing and planned highway and transit systems are less than or 
equal to the motor vehicle emissions budgets (MVEBs or ``budgets'') 
contained in all control strategy plans applicable to the area. An 
attainment or maintenance plan for the PM2.5 NAAQS should 
include budgets for the attainment year, each required RFP milestone 
year, or the last year of the maintenance plan, as appropriate, for 
direct PM2.5 and PM2.5 precursors subject to 
transportation conformity analyses. Budgets are generally established 
for specific years and specific pollutants or precursors and must 
reflect all of the motor vehicle control measures contained in the 
attainment and RFP demonstrations.\448\
---------------------------------------------------------------------------

    \448\ 40 CFR 93.118(e)(4)(v).
---------------------------------------------------------------------------

    Under the PM2.5 SIP Requirements Rule, Serious area 
PM2.5 attainment plans must include appropriate quantitative 
milestones and projected RFP emission levels for direct 
PM2.5 and all PM2.5 plan precursors in each 
milestone year.\449\ For an area designated nonattainment for the 2006 
PM2.5 NAAQS before January 15, 2015, the attainment plan 
must contain quantitative milestones to be achieved no later than three 
years after December 31, 2014, and every 3 years thereafter until the 
milestone date that falls within three years after the applicable 
attainment date.\450\ As the EPA explained in the preamble to the 
PM2.5 SIP Requirements Rule, it is important to include a 
post-attainment year quantitative milestone to ensure that, if the area 
fails to attain by the attainment date, the EPA can continue to monitor 
the area's progress toward attainment while the state develops a new 
attainment plan.\451\ Although the post-attainment year quantitative 
milestone is a required element of a Serious area plan, it is not 
necessary to demonstrate transportation conformity for 2026 or to use 
the 2026 budgets in transportation conformity determinations until such 
time as the area fails to attain the 2006 PM2.5 NAAQS.
---------------------------------------------------------------------------

    \449\ 40 CFR 51.1012(a), 51.1013(a)(1).
    \450\ 40 CFR 51.1013(a)(4) and 81 FR 58010, 58058 and 58063-
58064 (August 24, 2016).
    \451\ 81 FR 58010, 58063-58064.
---------------------------------------------------------------------------

    PM2.5 plans should identify budgets for direct 
PM2.5, NOX and all other PM2.5 
precursors for which on-road emissions are determined to significantly 
contribute to PM2.5 levels in the area for each RFP 
milestone year and the attainment year, if the plan demonstrates 
attainment. All direct PM2.5 SIP budgets should include 
direct PM2.5 motor vehicle emissions from tailpipes, brake 
wear, and tire wear. With respect to PM2.5 from re-entrained 
road dust and emissions of VOC, SO2, and/or ammonia, the 
transportation conformity provisions of 40 CFR part 93, subpart A, 
apply only if the EPA Regional Administrator or the director of the 
state air agency has made a finding that emissions of these pollutants 
within the area are a significant contributor to the PM2.5 
nonattainment problem and has so notified the MPO and Department of 
Transportation (DOT), or if the applicable implementation plan (or 
implementation plan submission) includes any of these pollutants in the 
approved (or adequate) budget as part of the RFP, attainment, or 
maintenance strategy.\452\
---------------------------------------------------------------------------

    \452\ 40 CFR 93.102(b)(3), 93.102(b)(2)(v), and 93.122(f); see 
also Conformity Rule preamble at 69 FR 40004, 40031-36 (July 1, 
2004).
---------------------------------------------------------------------------

    By contrast, transportation conformity requirements apply with 
respect to emissions of NOX unless both the EPA Regional 
Administrator and the director of the state air agency have made a 
finding that transportation-related emissions of NOX within 
the nonattainment area are not a significant contributor to the 
PM2.5 nonattainment problem and have so notified the MPO and 
DOT, or the applicable implementation plan (or implementation plan 
submission) does not establish an approved (or adequate) budget for 
such emissions as part of the RFP, attainment, or maintenance 
strategy.\453\
---------------------------------------------------------------------------

    \453\ 40 CFR 93.102(b)(2)(iv).
---------------------------------------------------------------------------

    It is not always necessary for states to establish motor vehicle 
emissions budgets for all of the PM2.5 precursors. The 
PM2.5 SIP Requirements Rule allows a state to demonstrate 
that emissions of certain precursors do not contribute significantly to 
PM2.5 levels that exceed the NAAQS in a nonattainment area, 
in which case the state may exclude such precursor(s) from its control 
evaluations for the specific NAAQS at issue. If a state successfully 
demonstrates that the emissions of one or more of the PM2.5 
precursors from all sources do not contribute significantly to 
PM2.5 levels in the subject area, then it is not necessary 
to establish motor vehicle emissions budgets for that precursor(s).
    Alternatively, the transportation conformity regulations contain 
criteria for determining whether emissions of one or more 
PM2.5 precursors are insignificant for transportation 
conformity purposes.\454\ For a pollutant or precursor to be considered 
an insignificant contributor based on the transportation conformity 
rule's criteria, the control strategy SIP must demonstrate that it 
would be unreasonable to expect that such an area would experience 
enough motor vehicle emissions growth in that pollutant and/or 
precursor for a NAAQS violation to occur. Insignificance determinations 
are based on factors such as air quality, SIP motor vehicle control 
measures, trends and projections of motor vehicle emissions, and the 
percentage of the total attainment plan emissions inventory for the 
NAAQS at issue that is comprised of motor vehicle

[[Page 17428]]

emissions. The EPA's rationale for providing for insignificance 
determinations is described in the July 1, 2004 revision to the 
Transportation Conformity Rule.\455\
---------------------------------------------------------------------------

    \454\ 40 CFR 93.109(f).
    \455\ 69 FR 40004.
---------------------------------------------------------------------------

    Transportation conformity trading mechanisms are allowed under 40 
CFR 93.124 where a state establishes appropriate mechanisms for such 
trades. The basis for the trading mechanism is the SIP attainment 
modeling that establishes the relative contribution of each 
PM2.5 precursor pollutant. The applicability of emission 
trading between conformity budgets for conformity purposes is described 
in 40 CFR 93.124(c).
    The EPA's process for determining the adequacy of a budget consists 
of three basic steps: (1) Notifying the public of a SIP submittal; (2) 
providing the public the opportunity to comment on the budgets during a 
public comment period; and (3) making a finding of adequacy or 
inadequacy.\456\ The EPA can notify the public by either posting an 
announcement that the EPA has received SIP budgets on the EPA's 
adequacy website (40 CFR 93.118(f)(1)), or through a Federal Register 
notice of proposed rulemaking when the EPA reviews the adequacy of an 
implementation plan budget simultaneously with its review and action on 
the SIP itself (40 CFR 93.118(f)(2)).
---------------------------------------------------------------------------

    \456\ 40 CFR 93.118(f).
---------------------------------------------------------------------------

2. Summary of State's Submission
    The 2018 PM2.5 Plan includes budgets for direct 
PM2.5 and NOX emissions for each RFP milestone 
year (2017, 2020, and 2023), the projected attainment year (2024), and 
one post-attainment year quantitative milestone (2026).\457\ The Plan 
establishes separate direct PM2.5 and NOX subarea 
budgets for each county, or partial county (for Kern County), in the 
San Joaquin Valley.\458\ CARB calculated the budgets using 
EMFAC2014,\459\ CARB's latest version of the EMFAC model for estimating 
emissions from on-road vehicles operating in California that was 
available at the time of Plan development, and the latest modeled 
vehicle miles traveled and speed distributions from the San Joaquin 
Valley MPOs from the Final 2017 Federal Transportation Improvement 
Plan, adopted in September 2016. The budgets reflect winter average 
emissions because those emissions are linked with the District's 
attainment demonstration for the 2006 24-hour PM2.5 NAAQS.
---------------------------------------------------------------------------

    \457\ 2018 PM2.5 Plan, App. D, Table 3-2.
    \458\ 40 CFR 93.124(c) and (d).
    \459\ EMFAC is short for EMission FACtor. The EPA announced the 
availability of the EMFAC2014 model for use in state implementation 
plan development and transportation conformity in California on 
December 14, 2015. The EPA's approval of the EMFAC2014 emissions 
model for SIP and conformity purposes was effective on the date of 
publication of the notice in the Federal Register. EMFAC2014 must be 
used for all new regional emissions analyses and CO, PM10 
and PM2.5 hot-spot analyses that are started on or after 
December 14, 2017, which is the end of the grace period for 
EMFAC2014.
---------------------------------------------------------------------------

    Consistent with the requirements set forth in the PM2.5 
SIP Requirements Rule, the SJV PM2.5 Plan contains RFP 
budgets for 2026, which is the year following the attainment year. As 
explained below, we are not taking action on the 2026 budgets at this 
time. The EPA is also not reviewing the submitted motor vehicle 
emissions budgets for 2017. These budgets would not be used in any 
future transportation conformity determinations because the plan 
contains budgets for 2020 and other years in the future.
    The direct PM2.5 budgets include tailpipe, brake wear, 
and tire wear emissions but do not include paved road dust, unpaved 
road dust, and road construction dust emissions.\460\ The State did not 
include budgets for VOC, SO2, or ammonia. As discussed in 
section IV.B of this preamble, the State submitted a PM2.5 
precursor demonstration documenting that control of these precursors 
would not significantly contribute to attainment of the 2006 
PM2.5 NAAQS, and the EPA is proposing to approve the 
precursor demonstration. Therefore, if the EPA approves the 
demonstration, the State would not be required to submit budgets for 
these precursors. The State included a discussion of the significance/
insignificance factors for ammonia, SO2, and VOC, which 
would demonstrate a finding of insignificance under the transportation 
conformity rule.\461\ The State is not required to include re-entrained 
road dust in the budgets under section 93.103(b)(3) unless the EPA or 
the State has made a finding that these emissions are significant. 
Neither the State nor the EPA has made such a finding. The Plan does 
include a discussion of the significance/insignificance factors for re-
entrained road dust.\462\ The budgets included in the 2018 
PM2.5 Plan are shown in Table 14.
---------------------------------------------------------------------------

    \460\ 2018 PM2.5 Plan, App. D, D-122 to D-123.
    \461\ 40 CFR 93.109(f).
    \462\ 2018 PM2.5 Plan, App. D, D-121 and D-122.

                                                 Table 14--Motor Vehicle Emission Budgets for the San Joaquin Valley for the 2006 PM2.5 Standard
                                                                                      [Winter average, tpd]
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                          2017                      2020                      2023                      2024                      2026
                          Budget year                          ---------------------------------------------------------------------------------------------------------------------------------
                                                                   PM2.5         NOX         PM2.5         NOX         PM2.5         NOX         PM2.5         NOX         PM2.5         NOX
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Fresno........................................................          0.9         29.3          0.9         25.9          0.8         15.5          0.8         15.0          0.8         14.3
Kern..........................................................          0.8         28.7          0.8         23.8          0.7         13.6          0.7         13.4          0.8         12.8
Kings.........................................................          0.2          5.9          0.2          4.9          0.2          2.9          0.2          2.8          0.2          2.7
Madera........................................................          0.2          5.5          0.2          4.4          0.2          2.6          0.2          2.5          0.2          2.3
Merced........................................................          0.3         11.0          0.3          9.1          0.3          5.5          0.3          5.3          0.3          4.9
San Joaquin...................................................          0.7         15.5          0.6         12.3          0.6          7.9          0.6          7.6          0.6          6.9
Stanislaus....................................................          0.4         12.3          0.4          9.8          0.4          6.2          0.4          6.0          0.4          5.6
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Source: 2018 PM2.5 Plan, Appendix D, Table 3-2. Budgets are rounded to the nearest tenth of a ton.
Note: We are not proposing any action at this time on the 2017 RFP or the 2026 post-attainment year RFP budgets.

    In the submittal letter for the 2018 PM2.5 Plan, CARB 
requested that the EPA limit the duration the approval of the budgets 
to the period before the effective date of the EPA's adequacy finding 
for any subsequently submitted budgets.\463\
---------------------------------------------------------------------------

    \463\ Letter dated May 9, 2019, from Richard W. Corey, Executive 
Officer, CARB to Mike Stoker, Regional Administrator, EPA Region 9, 
3.
---------------------------------------------------------------------------

Conformity Trading Mechanism
    The 2018 PM2.5 Plan also includes a proposed trading 
mechanism for transportation conformity analyses that would allow 
future decreases in NOX emissions from on-road mobile 
sources to offset any on-road increases in direct PM2.5 
emissions. For the 2006 PM2.5 NAAQS, the State is proposing 
to use

[[Page 17429]]

the 2:1 NOX: PM2.5 ratio. The ratio is based on a 
sensitivity analysis based on a 30% reduction of NOX or 
PM2.5 emissions and the corresponding impact on design 
values at sites in Bakersfield and Fresno.
    To ensure that the trading mechanism does not affect the ability of 
the San Joaquin Valley to meet the NOX budget, the 
NOX emission reductions available to supplement the 
PM2.5 budget would only be those remaining after the 
NOX budget has been met.\464\ The Plan also provides that 
the San Joaquin Valley MPOs shall clearly document the calculations 
used in the trading, along with any additional reductions of 
NOX and PM2.5 emissions in the conformity 
analysis.
---------------------------------------------------------------------------

    \464\ 2018 PM2.5 Plan, App. D, D-126 and D-127.
---------------------------------------------------------------------------

3. EPA's Evaluation and Proposed Action
    The EPA generally first conducts a preliminary review of budgets 
submitted with an attainment or maintenance plan for PM2.5 
for adequacy, prior to taking action on the plan itself, and did so 
with respect to the PM2.5 budgets in the 2018 
PM2.5 Plan. On June 18, 2019, the EPA announced the 
availability of the 2018 PM2.5 Plan with MVEBs and a 30-day 
public comment period. This announcement was posted on the EPA's 
Adequacy website at: https://www.epa.gov/state-and-local-transportation/state-implementation-plans-sip-submissions-currently-under-epa. The comment period for this notification ended on July 18, 
2019. We did not receive any comments during this comment period.
    Based on our proposal to approve the State's demonstration that 
emissions of ammonia, SO2, and VOCs do not contribute 
significantly to PM2.5 levels that exceed the 2006 
PM2.5 NAAQS in the San Joaquin Valley, as discussed in 
section IV.B of this preamble, and the information about ammonia, 
SO2, and VOC emissions in the Plan, the EPA proposes to find 
that it is not necessary to establish motor vehicle emissions budgets 
for transportation-related emissions of ammonia, SO2, and 
VOC to attain the 2006 24-hour PM2.5 NAAQS in the San 
Joaquin Valley. Based on the information about re-entrained road dust 
in the Plan and in accordance with 40 CFR 93.102(b)(3), the EPA 
proposes to find that it is not necessary to include re-entrained road 
dust emissions in the budgets for 2006 24-hour PM2.5 NAAQS 
in the San Joaquin Valley.
    For the reasons discussed in sections IV.D and IV.E of this 
proposed rule, the EPA is proposing to approve the RFP and attainment 
demonstrations, respectively, in the 2018 PM2.5 Plan. The 
2020 and 2023 RFP budgets and 2024 attainment budgets, as shown in 
Table 14 of this preamble, are consistent with these demonstrations, 
are clearly identified and precisely quantified, and meet all other 
applicable statutory and regulatory requirements including the adequacy 
criteria in 40 CFR 93.118(e)(4) and (5). For these reasons, the EPA 
proposes to approve the budgets listed in Table 14. We provide a more 
detailed discussion in section IV of the EPA's General Evaluation TSD. 
We are not proposing to approve the 2017 budget or the post-attainment 
year 2026 RFP budget at this time. The budgets that the EPA is 
proposing to approve relate to the 2006 24-hour PM2.5 NAAQS 
only, and our proposed approval does not affect the status of the 
previously-approved MVEBs for the 1997 PM2.5 NAAQS and 
related trading mechanism, which remain in effect for that 
PM2.5 NAAQS.
    Although the post-attainment year quantitative milestone is a 
required element of the Serious area plan, it is not necessary to 
demonstrate transportation conformity for 2026 or to use the 2026 
budgets in transportation conformity determinations until such time as 
the area fails to attain the 2006 PM2.5 NAAQS. Therefore, 
the EPA is not taking action on the submitted budgets for 2026 in the 
SJV PM2.5 Plan at this time. Additionally, the EPA has not 
yet started the adequacy process for the 2026 budgets.
    If the EPA were either to find adequate or to approve the post-
attainment milestone year budgets now, those budgets would have to be 
used in transportation conformity determinations that are made after 
the effective date of the adequacy finding or approval even if the San 
Joaquin Valley ultimately attains the PM2.5 NAAQS by the 
Serious area attainment date. This would mean that the San Joaquin 
Valley MPOs would be required to demonstrate conformity for the post-
attainment date milestone year and all later years addressed in the 
conformity determination (e.g., the last year of the metropolitan 
transportation plan) to the post-attainment date RFP budgets rather 
than the budgets associated with the attainment year for the area 
(i.e., the budgets for 2024). The EPA does not believe that it is 
necessary to demonstrate conformity using these post-attainment year 
budgets in areas that either the EPA anticipates will attain by the 
attainment date or in areas that attain by the attainment date.
    If and when the EPA determines that the San Joaquin Valley has 
failed to attain the 2006 24-hour PM2.5 NAAQS by the 
applicable attainment date, the EPA would begin the budget adequacy and 
approval processes for the post-attainment year (2026) budgets. If the 
EPA finds the 2026 budgets adequate or approves them, those budgets 
will have to be used in subsequent transportation conformity 
determinations. The EPA believes that initiating the process to act on 
the submitted post-attainment year MVEBs following a determination that 
the area has failed to attain by the Serious area attainment date 
ensures that transportation activities will not cause or contribute to 
new violations, increase the frequency or severity of any existing 
violations, or delay timely attainment or any required interim emission 
reductions or milestones in the San Joaquin Valley PM2.5 
nonattainment area, consistent with the requirements of CAA section 
176(c)(1)(B).
    As noted above, the State included a trading mechanism to be used 
in transportation conformity analyses that would be used in conjunction 
with the budgets in the 2018 PM2.5 Plan, as allowed for 
under 40 CFR 93.124(b). This trading mechanism would allow future 
decreases in NOX emissions from on-road mobile sources to 
offset any on-road increases in PM2.5, using a 2:1 
NOX:PM2.5 ratio. To ensure that the trading 
mechanism does not affect the ability to meet the NOX 
budget, the Plan provides that the NOX emission reductions 
available to supplement the PM2.5 budget would only be those 
remaining after the NOX budget has been met. The San Joaquin 
Valley MPOs will have to document clearly the calculations used in the 
trading when demonstrating conformity, along with any additional 
reductions of NOX and PM2.5 emissions in the 
conformity analysis. The trading calculations must be performed prior 
to the final rounding to demonstrate conformity with the budgets.
    The EPA has reviewed the trading mechanism as described on pages D-
125 through D-127 in Appendix D of the 2018 PM2.5 Plan and 
finds it is appropriate for transportation conformity purposes in the 
San Joaquin Valley for the 2006 24-hour PM2.5 NAAQS. The 
methodology for estimating the trading ratio for conformity purposes is 
essentially an update (based on newer modeling) of the approach that 
the EPA previously approved for the 2008 PM2.5 Plan for the 
1997 PM2.5 NAAQS \465\ and the 2012

[[Page 17430]]

PM2.5 Plan for the 2006 24-hour PM2.5 NAAQS.\466\ 
The State's approach in the previous plans was to model the ambient 
PM2.5 effect of areawide NOX emissions reductions 
and of areawide direct PM2.5 reductions, and to express the 
ratio of these modeled sensitivities as an interpollutant trading 
ratio.
---------------------------------------------------------------------------

    \465\ 80 FR 1816, 1841 (January 13, 2015) (noting the EPA's 
prior approval of MVEBs for the 1997 annual and 24-hour 
PM2.5 standards in the 2008 PM2.5 Plan at 76 
FR 69896).
    \466\ 81 FR 59876 (August 31, 2016).
---------------------------------------------------------------------------

    In the updated analysis for the 2018 PM2.5 plan, the 
State completed separate sensitivity analyses for the annual and 24-
hour standards and modeled only transportation related sources in the 
nonattainment area. The ratio the State is proposing to use for 
transportation conformity purposes is derived from air quality modeling 
that evaluated the effect of reductions in transportation-related 
NOX and PM2.5 emissions in the San Joaquin Valley 
on ambient concentrations at the Bakersfield-California Avenue, 
Bakersfield-Planz, Fresno-Garland, and Fresno-Hamilton & Winery 
monitoring sites. The modeling that the State performed to evaluate the 
effectiveness of NOX and PM2.5 reductions on 
ambient 24-hour concentrations showed NOX:PM2.5 
ratios that range from a high of 2.3 at the Bakersfield-California 
Avenue monitor to a low of 1.6 at the Fresno-Hamilton & Winery 
monitor.\467\ We find that the State's approach is a reasonable method 
to use to develop ratios for transportation conformity purposes. We 
therefore propose to approve the 2:1 NOX for 
PM2.5 trading mechanism as enforceable components of the 
transportation conformity program for the San Joaquin Valley for the 
2006 PM2.5 NAAQS. If approved, this trading ratio will 
replace the 8:1 NOX for PM2.5 trading ratio 
approved for the San Joaquin Valley 2012 PM2.5 Plan for the 
2006 PM2.5 NAAQS.
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    \467\ 2018 PM2.5 Plan, App. D, D-126.
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    Under the transportation conformity rule, once budgets are 
approved, they cannot be superseded by revised budgets submitted for 
the same CAA purpose and the same year(s) addressed by the previously 
approved SIP until the EPA approves the revised budgets as a SIP 
revision. In other words, as a general matter, such approved budgets 
cannot be superseded by revised budgets found adequate, but rather only 
through approval of the revised budgets, unless the EPA specifies 
otherwise in its approval of a SIP by limiting the duration of the 
approval to last only until subsequently submitted budgets are found 
adequate.\468\
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    \468\ 40 CFR 93.118(e)(1).
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    In the submittal letter for the SJV PM2.5 Plan, CARB 
requested that we limit the duration our approval of the budgets to the 
period before the effective date of the EPA's adequacy finding for any 
subsequently submitted budgets.\469\ The transportation conformity rule 
allows us to limit the approval of budgets.\470\ However, we will 
consider a state's request to limit an approval of its MVEBs only if 
the request includes the following elements: \471\
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    \469\ Letter dated May 9, 2019, from Richard W. Corey, Executive 
Officer, CARB, to Mike Stoker, Regional Administrator, EPA Region 9, 
3.
    \470\ 40 CFR 93.118(e)(1).
    \471\ 67 FR 69141 (November 15, 2002), limiting our prior 
approval of MVEBs in certain California SIPs.
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     An acknowledgement and explanation as to why the budgets 
under consideration have become outdated or deficient;
     A commitment to update the budgets as part of a 
comprehensive SIP update; and
     A request that the EPA limit the duration of its approval 
to the period before new budgets have been found to be adequate for 
transportation conformity purposes.
    CARB's request includes an explanation for why the budgets have 
become, or will become, outdated or deficient. In short, CARB has 
requested that we limit the duration of the approval of the budgets in 
light of the EPA's recent approval of EMFAC2017, an updated version of 
the model (EMFAC2014) used for the budgets in the 2018 PM2.5 
Plan.\472\ EMFAC2017 updates vehicle mix and emissions data of the 
previously approved version of the model, EMFAC2014.
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    \472\ On August 15, 2019, the EPA approved and announced the 
availability of EMFAC2017, the latest update to the EMFAC model for 
use by the State and local governments to meet CAA requirements. 84 
FR 41717.
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    In light of the EPA's approval of EMFAC2017, CARB explains that the 
budgets in the 2018 PM2.5 Plan, which we are proposing to 
approve in today's action, will become outdated and will need to be 
revised using EMFAC2017. In addition, CARB states that, without the 
ability to replace the budgets using the budget adequacy process, the 
benefits of using the updated data may not be realized for a year or 
more after the updated SIP (with the EMFAC2017-derived budgets) is 
submitted, due to the length of the SIP approval process. We find that 
CARB's explanation for limiting the duration of the approval of the 
budgets is appropriate and provides us with a reasonable basis for 
limiting the duration of the approval of the budgets.
    We note that CARB has not committed to update the budgets as part 
of a comprehensive SIP update, but as a practical matter, CARB must 
submit a SIP revision that includes updated demonstrations as well as 
the updated budgets to meet the adequacy criteria in 40 CFR 
93.118(e)(4).\473\ Therefore, we do not need a specific commitment for 
such a plan at this time. For the reasons provided above, and in light 
of CARB's explanation for why the budgets will become outdated and 
should be replaced upon an adequacy finding for updated budgets, we 
propose to limit the duration of our approval of the budgets in the 
2018 PM2.5 Plan to the period before we find revised budgets 
based on EMFAC2017 to be adequate.
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    \473\ Under 40 CFR 93.118(e)(4), the EPA will not find a budget 
in a submitted SIP to be adequate unless, among other criteria, the 
budgets, when considered together with all other emissions sources, 
are consistent with applicable requirements for RFP and attainment. 
40 CFR 93.118(e)(4)(iv).
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G. Major Stationary Source Control Requirements Under CAA Section 
189(e)

    Section 189(e) of the Act specifically requires that the control 
requirements applicable to major stationary sources of direct 
PM2.5 also apply to major stationary sources of 
PM2.5 precursors, except where the Administrator determines 
that such sources do not contribute significantly to PM2.5 
levels that exceed the standards in the area.\474\ The control 
requirements applicable to major stationary sources of direct 
PM2.5 in a Serious PM2.5 nonattainment area 
include, at minimum, the requirements of a nonattainment NSR permit 
program meeting the requirements of CAA sections 172(c)(5) and 
189(b)(3).\475\ As part of our January 20, 2016 final action to 
reclassify the San Joaquin Valley area as Serious nonattainment for the 
2006 PM2.5 standards, we established a February 21, 2017 
deadline for the State to submit nonattainment NSR SIP revisions 
addressing the requirements of CAA sections 189(b)(3) and 189(e) of the 
Act for the 2006 PM2.5 NAAQS, to the extent those 
requirements had not already been met by the nonattainment NSR SIP 
revisions due May 7, 2016 for purposes of implementing the 1997 
PM2.5 NAAQS.\476\
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    \474\ General Preamble at 13539 and 13541-42.
    \475\ CAA section 189(b)(1) (requiring that Serious area plans 
include provisions submitted to meet the requirements for Moderate 
areas in section 189(a)(1)).
    \476\ 81 FR 2993, 2994 (January 20, 2016) and 40 CFR 52.245(e).
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    California submitted nonattainment NSR SIP revisions to address the 
subpart 4 requirements for the San

[[Page 17431]]

Joaquin Valley Serious PM2.5 nonattainment area on November 
20, 2019.\477\ We are not proposing any action on this submission at 
this time. We will act on this submission through a separate 
rulemaking, as appropriate.
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    \477\ Letter dated November 15, 2019 from Richard W. Corey, 
Executive Officer, CARB, to Michael Stoker, Regional Administrator, 
EPA Region IX. California previously submitted nonattainment NSR SIP 
revisions for the San Joaquin Valley to address the subpart 4 
requirements for Moderate PM2.5 nonattainment areas, and 
the EPA approved these SIP revisions on September 17, 2014 (79 FR 
55637).
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V. Summary of Proposed Actions and Request for Public Comment

    For the reasons discussed in this proposed rule, under CAA section 
110(k)(3), the EPA proposes to approve, as a revision to the California 
SIP, the following portions of the SJV PM2.5 Plan for the 
2006 PM2.5 NAAQS:
     The 2013 base year emission inventories (CAA section 
172(c)(3));
     the demonstration that BACM, including BACT, for the 
control of direct PM2.5 and PM2.5 plan precursors 
will be implemented no later than 4 years after the area was 
reclassified (CAA section 189(b)(1)(B));
     the demonstration (including air quality modeling) that 
the Plan provides for attainment as expeditiously as practicable but no 
later than December 31, 2024 (CAA sections 189(b)(1)(A) and 188(e));
     plan provisions that require RFP toward attainment by the 
applicable date (CAA section 172(c)(2));
     quantitative milestones that are to be achieved every 
three years until the area is redesignated attainment and that 
demonstrate RFP toward attainment by the applicable attainment date 
(CAA section 189(c));
     motor vehicle emissions budgets for 2020, 2023, and 2024 
as shown in Table 14 of this proposed rule (CAA section 176(c) and 40 
CFR part 93, subpart A); and
     the inter-pollutant trading mechanism provided for use in 
transportation conformity analyses for the 2006 PM2.5 NAAQS, 
in accordance with 40 CFR 93.124(b).
    The EPA is proposing to grant the State's request for extension of 
the Serious area attainment date from December 31, 2019, to December 
31, 2024, based on a conclusion that the State has satisfied the 
requirements for such extensions in section 188(e) of the Act. We may, 
however, reconsider this proposal or deny California's request to 
extend the attainment date if the EPA concludes based on new 
information or public comments that the State has not satisfied the 
requirements for such extensions.
    The EPA is soliciting public comments on the issues discussed in 
this document. We will accept comments from the public on this proposal 
for the next 30 days.

VI. Statutory and Executive Order Reviews

    Under the Clean Air Act, the Administrator is required to approve a 
SIP submission that complies with the provisions of the Act and 
applicable federal regulations. 42 U.S.C. 7410(k); 40 CFR 52.02(a). 
Thus, in reviewing SIP submissions, the EPA's role is to approve state 
choices, provided that they meet the criteria of the Clean Air Act. 
Accordingly, this proposed action merely proposes to approve state 
plans as meeting federal requirements and does not impose additional 
requirements beyond those imposed by state law.
    For these reasons, this proposed action:
     Is not a ``significant regulatory action'' subject to 
review by the Office of Management and Budget under Executive Orders 
12866 (58 FR 51735, October 4, 1993) and 13563 (76 FR 3821, January 21, 
2011);
     Is not an Executive Order 13771 (82 FR 9339, February 2, 
2017) regulatory action because SIP approvals are exempted under 
Executive Order 12866;
     Does not impose an information collection burden under the 
provisions of the Paperwork Reduction Act (44 U.S.C. 3501 et seq.);
     Is certified as not having a significant economic impact 
on a substantial number of small entities under the Regulatory 
Flexibility Act (5 U.S.C. 601 et seq.);
     Does not contain any unfunded mandate or significantly or 
uniquely affect small governments, as described in the Unfunded 
Mandates Reform Act of 1995 (Pub. L. 104-4);
     Does not have Federalism implications as specified in 
Executive Order 13132 (64 FR 43255, August 10, 1999);
     Is not an economically significant regulatory action based 
on health or safety risks subject to Executive Order 13045 (62 FR 
19885, April 23, 1997);
     Is not a significant regulatory action subject to 
Executive Order 13211 (66 FR 28355, May 22, 2001);
     Is not subject to requirements of Section 12(d) of the 
National Technology Transfer and Advancement Act of 1995 (15 U.S.C. 272 
note) because application of those requirements would be inconsistent 
with the Clean Air Act; and
     Does not provide the EPA with the discretionary authority 
to address disproportionate human health or environmental effects with 
practical, appropriate, and legally permissible methods under Executive 
Order 12898 (59 FR 7629, February 16, 1994).
    In addition, the SIP is not approved to apply on any Indian 
reservation land or in any other area where the EPA or an Indian tribe 
has demonstrated that a tribe has jurisdiction. In those areas of 
Indian country, the proposed rule does not have tribal implications and 
will not impose substantial direct costs on tribal governments or 
preempt tribal law as specified by Executive Order 13175 (65 FR 67249, 
November 9, 2000).

List of Subjects in 40 CFR Part 52

    Environmental protection, Air pollution control, Ammonia, Carbon 
monoxide, Incorporation by reference, Intergovernmental relations, 
Nitrogen dioxide, Ozone, Particulate matter, Reporting and 
recordkeeping requirements, Sulfur dioxide, Volatile organic compounds.

    Authority:  42 U.S.C. 7401 et seq.

    Dated: February 27, 2020.
John W. Busterud,
Regional Administrator, Region IX.
[FR Doc. 2020-05914 Filed 3-26-20; 8:45 am]
 BILLING CODE 6560-50-P