[Federal Register Volume 82, Number 218 (Tuesday, November 14, 2017)]
[Proposed Rules]
[Pages 52683-52699]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2017-24539]


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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 52

[EPA-R10-OAR-2017-0051; FRL-9970-71-Region 10]


Air Plan Approval; OR, Oakridge; PM2.5 Moderate Plan, Finding of 
Attainment and Clean Data Determination

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.

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SUMMARY: The Environmental Protection Agency (EPA) is proposing to make 
a finding of attainment by the attainment date and a clean data 
determination (CDD) for the Oakridge-Westfir (Oakridge), Oregon fine 
particulate matter nonattainment area (Oakridge NAA). The finding is 
based upon quality-assured, quality-controlled, and certified ambient 
air monitoring data showing the area has monitored attainment of the 
2006 24-hour fine particulate matter (PM2.5) National 
Ambient Air Quality Standards (NAAQS) based on 2014-2016 data available 
in the EPA's Air Quality System (AQS) database. If finalized, this 
determination will not constitute a redesignation to attainment.
    The EPA also proposes to approve revisions to Oregon's State 
Implementation Plan (SIP) consisting of the updated Oakridge-Westfir 
PM2.5

[[Page 52684]]

Attainment Plan (Oakridge Update) submitted by the Oregon Department of 
Environmental Quality (ODEQ) on January 20, 2017. The purpose of the 
Oakridge Update, developed by Lane Regional Air Protection Agency 
(LRAPA) in coordination with the ODEQ, is to provide an attainment 
demonstration of the 2006 24-hour PM2.5 NAAQS and correct 
deficiencies in the 2012 Oakridge Attainment Plan.

DATES: Comments must be received on or before December 14, 2017.

ADDRESSES: Submit your comments, identified by Docket ID No. EPA-R10-
OAR-2017-0051 at https://www.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 the disclosure of which 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, 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: Christi Duboiski, 206-753-9081, 
[email protected].

SUPPLEMENTARY INFORMATION: Throughout this document, wherever ``we'', 
``us'' or ``our'' is used, it is intended to refer to the EPA.

Table of Contents:

I. Background for the EPA's Proposed Action
    A. Regulatory Background
    B. Oakridge NAA Background
II. Finding of Attainment by the Attainment Date and Clean Data 
Determination
III. The EPA's Evaluation of the Oakridge Update
    A. Emissions Inventories
    B. Pollutants Addressed
    C. Reasonably Available Control Measures/Reasonably Available 
Control Technology
    D. Modeling
    E. Attainment Demonstration
    F. Reasonable Further Progress (RFP) and Quantitative Milestones 
(QM)
    G. Contingency Measures
    H. Motor Vehicle Emissions Budgets
IV. Proposed Action
V. Incorporation by Reference
VI. Statutory and Executive Order Reviews

I. Background for the EPA's Proposed Action

A. Regulatory Background

    On October 17, 2006, the EPA strengthened the 24-hour 
PM2.5 NAAQS by lowering the level of the standard from 65 
micrograms per cubic meter ([mu]g/m\3\) to 35 [mu]g/m\3\ in order to 
provide increased protection of public health (40 CFR 50.13).\1\ 
Epidemiological studies have shown statistically significant 
correlations between elevated PM2.5 (particulate matter 2.5 
micrometers in diameter and smaller) levels and premature mortality. 
Other important adverse health effects associated with elevated 
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. Individuals particularly sensitive to PM2.5 
exposure include older adults, people with heart and lung disease, and 
children (78 FR 3088, January 15, 2013). 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 
among precursor pollutants such as nitrogen oxides, sulfur oxides, 
volatile organic compounds, and ammonia (``secondary 
PM2.5'').\2\
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    \1\ See 71 FR 61224 (October 17, 2006). The EPA set the first 
NAAQS for PM2.5 on July 18, 1997 (62 FR 36852), including 
annual standards of 15.0 [mu]g/m\3\ based on a 3-year average of 
annual mean PM2.5 concentrations and 24-hour (daily) 
standards of 65 [mu]g/m\3\ based on a 3-year average of 98th 
percentile 24-hour concentrations (40 CFR 50.7). Unless otherwise 
noted, all references to the PM2.5 standard in this 
notice are to the 2006 24-hour standard of 35 [mu]g/m\3\ codified at 
40 CFR 50.13.
    \2\ See EPA, Regulatory Impact Analysis for the Final Revisions 
to the National Ambient Air Quality Standards for Particulate Matter 
(EPA-452/R-12-005, December 2012), p. 2-1.
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    Following promulgation of a new or revised NAAQS, the EPA is 
required by section 107(d)(1) of the CAA to designate areas throughout 
the United States as attainment, nonattainment, or unclassifiable for 
the NAAQS. Nonattainment areas include both areas that are violating 
the NAAQS, and nearby areas with emissions sources or activities that 
contribute to violations in those areas. States with areas designated 
nonattainment are required to prepare and submit a plan for attaining 
the NAAQS in the area as expeditiously as practicable.
    The requirements for attainment plans for the 2006 24-hour 
PM2.5 NAAQS include the general nonattainment area planning 
requirements in CAA section 172 of title I, part D, subpart 1 (subpart 
1) and the additional planning requirements specific to particulate 
matter in CAA sections 188 and 189 of title I, part D, subpart 4 
(subpart 4). The EPA has a longstanding general guidance document that 
interprets the 1990 amendments to the CAA, commonly referred to as the 
``General Preamble'' (57 FR 13498, April 16, 1992). The General 
Preamble addresses the relationship between subpart 1 and subpart 4 
requirements and provides recommendations to states for meeting 
statutory requirements for particulate matter nonattainment planning. 
Specifically, the General Preamble explains that requirements 
applicable to Moderate area nonattainment SIPs are set forth in subpart 
4, but such SIPs must also meet the general nonattainment planning 
provisions in subpart 1, to the extent these provisions ``are not 
otherwise subsumed by, or integrally related to,'' the more specific 
subpart 4 requirements (57 FR 13538). On August 16, 1994, the EPA 
promulgated an addendum to the General Preamble providing additional 
guidance for particulate matter nonattainment areas (59 FR 41988). 
Additionally, on August 24, 2016, the EPA issued a final rule, Fine 
Particulate Matter National Ambient Air Quality Standards: State 
Implementation Plan Requirements (PM2.5 SIP Requirements 
Rule) (81 FR 58009), to clarify our interpretations of the statutory 
requirements that apply to PM2.5 nonattainment areas.
    The requirements of subpart 1 for attainment plans include, among 
other things: (i) The section 172(c)(1) requirements to provide for the 
implementation of reasonably available control measures (RACM), 
including reasonably available control technology (RACT), and 
attainment of the NAAQS; (ii) the section 172(c)(2) requirement to 
demonstrate reasonable further progress (RFP); (iii) the section 
172(c)(3) requirement for emissions inventories; and (iv) the section 
172(c)(9) requirement for contingency measures.
    The subpart 4 requirements for Moderate areas are generally 
comparable with the subpart 1 requirements and include: (i) Section 
189(a)(1)(B) requirements to demonstrate attainment by the outermost 
statutory Moderate area attainment date (i.e., the end of the sixth 
calendar year following designation) or

[[Page 52685]]

that attainment by such date is impracticable; (ii) section 
189(a)(1)(C) requirements to ensure RACM will be implemented within 
four years of designation; (iii) section 189(c) requirements for RFP 
and quantitative milestones (QMs); and (iv) section 189(e) control 
requirements for precursor emissions from major stationary sources. In 
this action, the EPA is evaluating the Oakridge Update for compliance 
with the statutory and regulatory requirements applicable to Moderate 
PM2.5 nonattainment areas.

B. Oakridge NAA Background

    In 1994, the EPA designated Oakridge a nonattainment area for 
PM10--particulate matter ten micrometers and smaller. In 
1996, LRAPA in coordination with the ODEQ, prepared and submitted a 
PM10 attainment plan for Oakridge. The EPA approved it on 
March 15, 1999 (64 FR 12751). On July 26, 2001, EPA published a finding 
of attainment for the Oakridge PM10 NAA (66 FR 38947). 
However, the designation status in 40 CFR part 81 remains Moderate 
nonattainment for the area until such time as LRAPA meets the CAA 
requirements for redesignaton to attainment. A redesignation request 
and maintenance plan for PM10 has not been submitted. The 
area has continued to attain the PM10 NAAQS.
    In 1997, the EPA revised the particulate standard to include 
PM2.5 at a daily standard of 65 [mu]g/m\3\. Due to the same 
set of control measures that it used to address exceedances of the 
PM10 standard, Oakridge successfully remained below the 
PM2.5 standard promulgated in 1997. When the EPA tightened 
the PM2.5 standard from 65[mu]g/m\3\ to 35[mu]g/m\3\ in 
2006, Oakridge was found to be violating the new standard. The air 
quality monitoring data at the Willamette Activity Center (WAC) was 
evaluated for 2006-2008, resulting in a design value of 40 [mu]g/m\3\. 
The EPA designated Oakridge, Oregon as nonattainment for the 2006 24-
hour PM2.5 NAAQS on November 13, 2009 (74 FR 58689), 
prompting the development of the PM2.5 Attainment Plan for 
the Oakridge, Oregon NAA (Oakridge Attainment Plan). The EPA 
subsequently classified the area as Moderate nonattainment for the 2006 
24-hour PM2.5 standard (79 FR 31565, June 2, 2014).\3\
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    \3\ On January 4, 2013, the D.C. Circuit Court issued a decision 
in NRDC v. EPA, 706 F.3d 428, holding that the EPA erred in 
implementing the 1997 PM2.5 NAAQS pursuant to the general 
implementation provisions of subpart 1 of Part D of Title I of the 
CAA (subpart 1), rather than the particulate-matter-specific 
provisions of subpart 4 of Part D of Title I (subpart 4). Prior to 
the January 4, 2013 Court decision, states had worked towards 
meeting the air quality goals of the 2006 PM2.5 NAAQS in 
accordance with the EPA regulations and guidance derived from 
subpart 1 of Part D of Title I of the CAA. The EPA considered this 
history in issuing the PM2.5 Subpart 4 Nonattainment 
Classification and Deadline Rule (79 FR 31566, June 2, 2014) that 
identified the initial classification under subpart 4 for areas 
currently designated nonattainment for the 1997 and/or 2006 
PM2.5 standards as moderate.
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    On December 12, 2012, LRAPA, in coordination with the ODEQ, 
submitted the Oakridge Attainment Plan. On October 21, 2016, the EPA 
finalized partial approval and partial disapproval of this plan (81 FR 
72714). In that action, the EPA approved the description of the 
Oakridge NAA and listing as nonattainment, and the 2008 base year 
emission inventory as meeting the section 172(c)(3) requirement for 
emissions inventories. The EPA disapproved all other elements of the 
submittal. The disapproval action for the Oakridge Attainment Plan 
started a sanctions clock for the imposition of offset sanctions and 
highway sanctions 18 months and 24 months respectively after the 
November 21, 2016 effective date, pursuant to section 179(a) of the CAA 
and our regulations at 40 CFR 52.31. In addition to sanctions, the EPA 
must promulgate a FIP no later than two years from the date of the 
finding if the deficiency has not been corrected within that time 
period.
    The Oakridge Attainment Plan included control measures that were 
fully implemented and modeled attainment by the December 2014 deadline. 
However, leading up to the deadline, the Identification of 
Nonattainment Classification and Deadlines for Submission of State 
Implementation Plan (SIP) Provisions for the 1997 Fine Particle (PM2.5) 
National Ambient Air Quality Standard (NAAQS) and 2006 PM2.5 NAAQS was 
finalized. The rule classified Oakridge as Moderate and established 
December 31, 2015, as the attainment date deadline for the Oakridge NAA 
(79 FR 31565, June 2, 2014). This decision was based on the fact that 
subpart 4 of the CAA requires a Moderate area attainment date to be no 
later than the end of the 6th calendar year after designation. The 
applicable attainment date for Oakridge changed from December 2014 to 
December 2015.
    In order to measure progress towards meeting the attainment date, 
both LRAPA and the EPA followed monitoring data closely to ensure the 
area was meeting targets consistent with the modeling demonstration 
submitted in the 2012 Oakridge Attainment Plan. Prior to the December 
31, 2015, attainment date deadline, LRAPA determined Oakridge would not 
come into attainment based on 2013-2015 monitoring data. Under section 
188(d), the EPA has discretion to grant an extension to the attainment 
date for an area if the state requests the extension and meets the 
statutory criteria for such an extension. On December 14, 2015, LRAPA 
requested a 1-year extension of the 2015 attainment date for the 
Oakridge NAA. On July 18, 2016, the EPA granted a 1-year extension of 
the 2006 24-hour attainment date for the Oakridge NAA (81 FR 46612) 
from December 31, 2015 to December 31, 2016 (extended attainment date), 
on the basis that the State met the criteria for such an extension 
under the CAA.
    Notwithstanding the extension of the attainment date to December 
31, 2016, the applicable Moderate area attainment demonstration date 
for the Oakridge NAA remains December 31, 2015. The PM2.5 
SIP Requirements Rule provides that a state's modeled attainment 
demonstration needs to establish that an area will attain the NAAQS by 
the projected attainment date. Practically speaking, this is considered 
satisfied by the modeling showing that the 98th percentile is below the 
standard for the attainment year (81 FR 58010, at page 58054).
    The EPA authorizes this approach because of the potential 
availability of extensions of the attainment date under relevant 
provisions of the CAA. In other words, if ambient data show attainment-
level concentrations in the final statutory attainment year, but the 
three-year average does not demonstrate attainment, a state may be 
eligible for up to two 1-year extensions of the attainment date. See 40 
CFR 51.1005. Extensions of the attainment date are available to 
accommodate states that may be able to attain the NAAQS by the extended 
attainment date, even if the measured design value for an area does not 
meet the NAAQS by the end of the 6th calendar year after designation. 
For this reason, the EPA's PM2.5 SIP Requirements Rule 
indicates that it is acceptable for a state to model air quality levels 
for the final statutory attainment year in which the area is required 
to attain the standard (in this case 2015).
    Because the initial Oakridge Attainment Plan did not adequately 
address the PM2.5 problems in the airshed or meet the 
requirements of the CAA and the PM2.5 SIP Requirements Rule, 
LRAPA developed the Oakridge Update that was subsequently adopted and 
submitted by the ODEQ to the EPA on January 20, 2017. The Oakridge 
Update was submitted to satisfy the requirement for an updated

[[Page 52686]]

comprehensive 2008 base year emission inventory and the 2015 attainment 
projected inventory for direct PM2.5 emissions and all 
PM2.5 precursors, an analysis and selection of reasonably 
available control measures and reasonably available control 
technologies (RACM and RACT), an attainment demonstration based on 
permanent and enforceable requirements, contingency measures, and 
quantitative milestones (QM) demonstrating reasonable further progress 
(RFP) toward attainment. The attainment plan's strategy for controlling 
direct PM2.5 emissions relies primarily on an episodic wood 
stove curtailment program and a program to change out uncertified wood 
stoves.

II. Finding of Attainment by the Attainment Date and Clean Data 
Determination

    Under CAA section 188(b)(2) the EPA is required to determine within 
six months of the applicable attainment date whether a nonattainment 
area attained the standard by that date. As discussed above, on July 
18, 2016, the EPA granted a 1-year extension of the attainment date 
from December 31, 2015 to December 31, 2016 (81 FR 46612). Under the 
EPA regulations at 40 CFR part 50, Appendix N, the 2006 primary and 
secondary 24-hour PM2.5 NAAQS are met within a nonattainment 
area when the 24-hour PM2.5 NAAQS design value at each 
eligible monitoring site is less than or equal to 35 [mu]g/m\3\. Three 
years of valid annual PM2.5 98th percentile mass 
concentrations are required to produce a valid 24-hour PM2.5 
NAAQS design value.
    The EPA's finding of attainment is based upon data that has been 
collected and quality-assured in accordance with 40 CFR part 58 and 
recorded in the EPA Air Quality System (AQS) database. Ambient air 
quality monitoring data for the 3-year period must meet data 
completeness requirements. The ambient air quality monitoring data 
completeness requirements are met when quarterly data capture rates for 
all four quarters in a calendar year are at least 75 percent.
    The EPA reviewed the PM2.5 ambient air monitoring data 
from the Willamette Activity Center (WAC) (AQS site 41-039-2013) 
consistent with the requirements contained in 40 CFR part 50, as 
recorded in the EPA AQS database for the Oakridge NAA. For purposes of 
determining attainment by the December 31, 2016 extended attainment 
date, the EPA determined that the data recorded in the AQS database was 
certified and complete.
    The design value (the metrics calculated in accordance with 40 CFR 
part 50, appendix N, for determining compliance with the NAAQS) for the 
2006 24-hour PM2.5 NAAQS for the years 2014-2016 at the WAC 
was calculated to be 31 [mu]g/m\3\, which is less than the standard of 
35 [mu]g/m\3\. See Table 1 below for the annual 98th percentiles and 3-
year design value for the 2014-2016 monitoring period. On the basis of 
this review, we are proposing to determine, based on complete, quality-
assured, and certified data for 2014-2016, that the Oakridge NAA 
attained the 2006 24-hour PM2.5 NAAQS by the extended 
attainment date. This determination of attainment by the attainment 
date does not constitute a redesignation to attainment. Rather, 
redesignations require states to meet a number of additional statutory 
criteria in CAA section 107(d)(3)(E), including EPA approval of a state 
plan demonstrating maintenance of the air quality standard for 10 years 
after redesignation. CAA section 107(d)(3)(E)(iv).

                             Table 1--2014-2016 Oakridge Area PM2.5 Monitoring Data
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                                                           98th percentile  ([mu]g/m\3\)           2014-2016 24-
                                                 ------------------------------------------------  hour  design
          Monitor name              AQS site ID                                                   value  ([mu]g/
                                                       2014            2015            2016            m\3\)
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Willamette Activity Center......     41-039-2013            41.1            28.9            21.7              31
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    Additionally, the EPA is proposing to determine that the area has 
clean data for demonstrating attainment of the 2006 24-hr 
PM2.5 NAAQS. A clean data determination (CDD) can be made 
upon a determination by the EPA that a Moderate PM2.5 NAA is 
attaining the PM2.5 NAAQS. Under a CDD, the requirements for 
the area to submit an attainment demonstration, associated RACM, RFP 
plan, contingency measures, and any other planning SIP requirements 
related to attainment of the 2006 24-hour PM2.5 NAAQS are 
suspended for so long as the area continues to meet the relevant NAAQS 
(40 CFR 51.1015, August 24, 2016), and the FIP and sanctions clocks are 
also tolled for the pendency of the CDD. If the EPA subsequently 
determines that the area is in violation of the 2006 24-hour 
PM2.5 NAAQS, the EPA would rescind the CDD, the state would 
again be required to submit the suspended attainment plan elements to 
the EPA, and the FIP and sanctions clocks would resume. See 40 CFR 
51.1015(a)(2).
    Although a CDD suspends the requirement for submission of certain 
attainment planning elements, it does not relieve the EPA of its 
responsibility to take action on a state's SIP submission. Oregon 
submitted the Oakridge Update to address the previously disapproved 
elements of the SIP and EPA is proposing to approve the state's 
revisions. In the event that EPA determines in its final action that 
the Oakridge Update should not be approved, the Clean Data 
Determination (if finalized as proposed) would suspend Oregon's 
obligation to submit a revised SIP to address the attainment planning 
requirements related to attainment of the 2006 24-hour PM2.5 
NAAQS, and as noted above, would toll the FIP and sanctions clocks that 
were started by the EPA's prior disapprovals as long as the area 
continues to attain the standard.
    Neither the proposed finding of attainment by the attainment date 
nor CDD is equivalent to the redesignation of the area to attainment. 
This proposed action, if finalized, will not constitute a redesignation 
to attainment under section 107(d)(3)(E) of the CAA, because the state 
must have an approved maintenance plan for the area as required under 
section 175A of the CAA, and a determination that the area has met the 
other requirements for redesignation in order to be redesignated to 
attainment. The designation status of the area will remain 
nonattainment for the 2006 PM2.5 NAAQS until such time as 
the EPA determines that the area meets the CAA requirements for 
redesignation to attainment in CAA section 107(d)(3)(E).

III. The EPA's Evaluation of the Oakridge Update

    On January 20, 2017, the ODEQ in coordination with LRAPA submitted 
the Oakridge Update to satisfy the Moderate

[[Page 52687]]

nonattainment area CAA requirements. In accordance with Sections 172(c) 
and 189 of the CAA, the Oakridge Update includes emissions inventories, 
an evaluation of precursors for control in the area, RACM/RACT 
demonstrations for direct PM2.5 and PM2.5 
precursors, an attainment demonstration, QM and RFP requirements, and 
contingency measures. The SIP submittal also addresses motor vehicle 
emissions budgets (MVEBs). Each of these elements is discussed below. 
The primary control strategy in the Oakridge Update is reducing 
emissions from residential wood combustion.
    The air pollution ordinances adopted by the City of Oakridge from 
2012-2016 (ordinances 903, 913, 914 and 920) require emission 
reductions contributing to the 2015 attainment demonstration and the 
monitored attainment of the 2006 24-hr PM2.5 NAAQS by the 
December 31, 2016, extended attainment date. Each ordinance, in 
succession, provides further strengthening of the control measures and 
maintains the integrity of the prior ordinance(s). The most recent city 
ordinance (ordinance 920), passed by the City of Oakridge and adopted 
by LRAPA on November 21, 2016, supersedes the previous air pollution 
ordinances and requires the continued implementation of the control 
strategies in a manner that is both permanent and enforceable.
    The EPA has evaluated the Oakridge Update to determine whether it 
meets the applicable CAA requirements of subpart 1 and subpart 4, as 
specified in the PM2.5 SIP Requirements Rule. Based on this 
evaluation, the EPA is proposing to approve the following elements of 
the Oakridge Update.

A. Emissions Inventories

1. Requirements for Emissions Inventories
    Section 172(c)(3) of the CAA requires a state with an area 
designated as nonattainment to submit a ``comprehensive, accurate, 
current inventory of actual emissions from all sources of the relevant 
pollutant'' for the nonattainment area. By requiring an accounting of 
actual emissions from all sources of the relevant pollutants in the 
area, this section provides for the base year inventory to include all 
emissions from sources in the nonattainment area that contribute to the 
formation of a particular NAAQS pollutant. For the 2006 24-hour 
PM2.5 NAAQS, this includes direct PM2.5 
(condensable and filterable) as well as the precursors to the formation 
of secondary PM2.5: Nitrogen oxides (NOX), sulfur 
dioxide (SO2), volatile organic compounds (VOCs), and 
ammonia (NH3) (40 CFR 51.1008; 81 FR 58028). Inclusion of 
PM2.5 and all of the PM2.5 precursors in the 
emissions inventory is necessary in order to inform other aspects of 
the attainment plan development process, such as ascertaining which 
pollutants a state must control in order to attain the NAAQS in the 
area expeditiously.
    In addition to the base year inventory submitted to meet the 
requirements of CAA section 172(c)(3), the state must also submit an 
attainment projected inventory for the NAA for the attainment year and 
each QM year, and any other year of significance for meeting applicable 
CAA requirements. Projected emission inventories for future years must 
account for, among other things, the ongoing effects of economic growth 
and adopted emissions control requirements, and are expected to be the 
best available representation of future emissions. The SIP submission 
should include documentation explaining how the state calculated the 
emissions data for the base year and projected inventories. The 
specific PM2.5 emissions inventory requirements are set 
forth in 40 CFR 51.1008. The EPA has provided additional guidance for 
developing PM2.5 emissions inventories in Emissions 
Inventory Guidance for Implementation of Ozone and Particulate Matter 
National Ambient Air Quality Standards (NAAQS) and Regional Haze.\4\
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    \4\ The EPA's Emissions Inventory Guidance for Implementation of 
Ozone and Particulate Matter National Ambient Air Quality Standards 
(NAAQS) and Regional Haze is available at https://www.epa.gov/air-emissions-inventories/emissions-inventory-guidance-documents.
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2. Emissions Inventories in the Oakridge Update
    The Oakridge Update has two emissions inventories for the area: a 
2008 base year inventory for the nonattainment area and the 2015 
attainment projected inventory for the nonattainment area. In addition, 
LRAPA developed a projected emissions inventory for 2016 for 
informational purposes to demonstrate the further effectiveness of the 
field compliance improvements and curtailment program for year 2015. 
Each inventory presents PM2.5 emissions and emissions of all 
PM2.5 precursors (NOX, VOCs, NH3, and 
SO2) to meet the comprehensive emissions inventory 
requirements of CAA section 172(c) and section 189(a)(1)(B) for the 
2006 24-hour PM2.5 NAAQS. LRAPA provided inventories from 
all sources in the Oakridge NAA, including stationary point sources, 
stationary nonpoint (area sources), on-road mobile sources and non-road 
mobile sources.
    The inventories are based on Typical Season Day and Worst Case Day 
emissions. LRAPA chose to develop a seasonal inventory representing a 
four-month period in 2008 (January, February, November, and December) 
during the wood-heating season. The agency examined ambient 
PM2.5 data from the Willamette Activity Center and 
determined that values approaching the 2006 24-hour PM2.5 
NAAQS of 35 [mu]g/m\3\ only occur in the four-months when low 
temperatures spur higher home heating emissions and when stagnant air 
masses inhibit dispersion of air pollution. Therefore, the Typical 
Season Day inventory represents a seasonal inventory for the period of 
the year relevant for attainment planning. The Typical Season Day 
emissions are the daily rate of emissions for the four-month season. 
However, stagnant meteorological conditions are highly episodic and 
only occur for a portion of the season. Outside of these meteorological 
conditions, PM2.5 levels are well below the 2006 24-hour 
PM2.5 NAAQS. To best represent emissions during exceedances 
of the standard rather than an average of polluted and clean periods, 
LRAPA developed a ``Worst Case Day'' emission inventory for weather 
conditions that represent exceedance days.
    Stationary Point Sources: The only operating industrial point 
sources within the Oakridge NAA are two minor aggregate industry 
sources (a rock crusher and concrete batch plant which shut down in 
2014). These two minor sources together contribute less than 1% to base 
year and 0% to future year emission inventories. For the base year 
inventory, actual emissions were based on average actual production 
rates and calculated emissions during the months of November-February 
(2008-2011), worst-case day emissions were based on actual production 
rates and calculated emissions during the highest production month 
during November-February (2008-2011). On May 17, 2017, LRAPA submitted 
a clarification to the future year (2015) emissions reported in the 
Oakridge Update. The actual point source emissions based on actual 
production rates calculated for 2015 (January, February, November, and 
December) are 0% since the concrete batch plant is no longer in 
operation and the rock crushing operation did not operate in 2015.
    Nonpoint/Area Sources: The most significant source category is 
residential wood combustion (RWC). Emissions from certified and non-
certified wood

[[Page 52688]]

stoves, fireplaces, and pellet stoves account for about 86% of the base 
year direct PM2.5 emissions and 84% of the projected 2015 
emissions on worst case winter days. To estimate emissions from RWC, 
LRAPA conducted a survey for the 2009-2010 heating season. The survey 
provided LRAPA with information on how many homes use various types of 
wood-heating devices, the amount of wood burned, and other information 
on wood-heating practices. The survey report, data, and additional RWC 
emission calculation details are included in Appendix D-2 of the 2012 
Oakridge Attainment Plan. The only other nonpoint area source category 
with potential emissions is backyard burning which is banned in 
Oakridge during November-February. These emissions are estimated as 4.7 
lb./day on worst-case days.
    On-road and Non-road Sources: Road dust and tailpipe emissions from 
motor vehicles were initially calculated by the Lane Council of 
Governments (LCOG) by applying emission factors from the EPA MOVES2010a 
computer program. These were recently updated by the ODEQ in 2016 using 
the EPA MOVES2014a program using inputs and VMT compiled by LCOG in 
2012 and incorporating the effects of three new federal emission 
control programs. Emissions from railroads were provided by Union 
Pacific Railroad.
    It has been determined that condensable emissions currently are not 
required to be reported for the mobile source and residential wood 
combustion portion of the inventory since the EPA's best tools to date 
do not have a declarative answer for the condensable emissions portion 
for these sources. In addition, the point source, non-road and the 
``all other stationary area source'' categories, which constitute 0.1%, 
1% and 1% respectively of the worst-case day direct PM2.5 
emissions (2008 base year EI) and 0%, 1% and 1% respectively of the 
worst-case day emissions (2015 projected year EI), are too small to 
justify the need to break out condensable emissions. Thus the 2008 and 
2015 inventories for the Oakridge NAA do not include separately 
reported filterable and condensable components of direct 
PM2.5 emissions.
a. 2008 Base Year Emissions Inventory for the Nonattainment Area
    LRAPA selected the year 2008 as the base year of the emissions 
inventory for the nonattainment area. The 2008 base year inventory is 
one of the three years used to designate the area as nonattainment and 
was inventoried for the National Emission Inventory. It is also the 
middle year of the five-year period, 2006-2010, used for determining 
the base design value. This inventory provides the basis for the 
control measure analysis and the attainment demonstration in the 
Oakridge Update.
    The 2008 base year emission inventory for the nonattainment area 
was initially submitted as part of the 2012 Oakridge Attainment Plan 
and approved in a final rulemaking action completed on October 21, 2016 
(81 FR 72714). The Oakridge Update contains a revised 2008 base year 
emission inventory for the nonattainment area because an updated 
version of MOVES (2014a) was available for calculating on-road 
emissions. LRAPA surveyed all source sectors within the nonattainment 
area and developed accurate, actual emissions for sources as they 
existed in 2008 using well established techniques. Table 2 presents a 
summary of both seasonal inventories and the annual average daily 
precursor emissions.

Table 2--2008 PM2.5 Base Year Typical Season Day and Worst-Case Day Emissions; and 2008 Precursor Annual Average
                                                 Daily Emissions
----------------------------------------------------------------------------------------------------------------
                                      Typical season  Worst case day      Annual average daily values lbs/day
                                        day lbs/per     lbs/per day  -------------------------------------------
        Source type category                day      ----------------
                                     ----------------                    SO2        NOX        VOC        NH3
                                           PM2.5           PM2.5
----------------------------------------------------------------------------------------------------------------
Stationary Point (actuals)..........             0.5             0.9       * na       * na       * na       * na
Nonpoint/Area.......................           479.5             480        2.9       12.8      216.8        5.3
On-road.............................            41.4            64.7       10.6      866.7      434.4       13.8
Non-road............................             6.0             6.0        1.3        101       18.2        .05
                                     ---------------------------------------------------------------------------
    Total...........................             527             552         15        980        670       19.2
----------------------------------------------------------------------------------------------------------------
* These emissions are accounted for in the 2008 NEI but are grouped into the nonpoint/area source category.

b. Attainment Projected Emissions Inventory for the Nonattainment Area
    In addition to developing a 2008 base year inventory, LRAPA 
developed a projected year inventory for 2015. This inventory is 
relevant to the December 31, 2015 attainment demonstration. LRAPA 
developed the 2015 projected year inventory by estimating the impact on 
emissions from anticipated demographic and economic trends and from 
adopted federal, state and local control measures in effect through 
December 31, 2014. A summary of the Oakridge NAA 2015 projected 
seasonal inventory is provided in Table 3.

Table 3--2015 PM2.5 Estimated Typical Season Day and Worst-Case Day Emissions; and 2014 Annual Average Precursor
                                                    Emissions
----------------------------------------------------------------------------------------------------------------
                                      Typical season  Worst case day      Annual average daily values lbs/day
                                        day lbs/per     lbs/per day  -------------------------------------------
        Source type category                day      ----------------
                                     ----------------                    SO2        NOX        VOC        NH3
                                           PM2.5           PM2.5
----------------------------------------------------------------------------------------------------------------
Stationary Point (actuals)..........               0               0          0          0          0          0
Nonpoint/Area.......................           444.8           334.5        3.0       10.7      120.4        2.1
On-road.............................            24.7            38.5        3.0      598.3      339.8       11.5
Non-road............................             6.0             6.0        1.1       77.3       14.4        .05
                                     ---------------------------------------------------------------------------

[[Page 52689]]

 
    Total...........................             475             379          7        686        475         14
----------------------------------------------------------------------------------------------------------------

3. The EPA's Evaluation and Proposed Action: Emissions Inventories for 
the Nonattainment Area
    The EPA has reviewed the results, procedures, and methodologies for 
the Oakridge NAA emissions inventories. The EPA has determined that the 
2008 base year inventory for the nonattainment area and the 2015 
attainment projected inventory for the nonattainment area are based on 
the most current and accurate information available to LRAPA at the 
time the Oakridge Update and its inventories were being developed. The 
selection of 2008 as a base year is consistent with emissions inventory 
requirements in 40 CFR 51.1008(a)(1)(i) because it is one of three 
years used to designate the area as nonattainment and it is also a year 
already inventoried for the National Emission Inventory. Weather 
conditions in 2008 were typical and temperature-dependent emissions 
from home heating and from mobile sources are considered representative 
for the 2006-2010 period. The selection of 2015 for the attainment 
projected inventory for the nonattainment area is consistent with 40 
CFR 51.1008(2)(2)(i) because 2015 is the attainment year in the 
attainment demonstration.
    The EPA finds the worst case day (episodic) approach that LRAPA 
used for the 2008 and 2015 inventories to be consistent with the 
PM2.5 SIP Requirements Rule in which the EPA stated that an 
episodic period developed in order to reflect periods of higher 
emissions during periods of high ambient PM2.5 can help, in 
some situations, to ensure the nonattainment area inventory reflects 
the emissions conditions that led to the nonattainment designation for 
the area (81 FR 58030). This seasonal Worst Case Day inventory is the 
most relevant and accurate for nonattainment area planning.
    Additionally, the 2008 and 2015 inventories sufficiently account 
for PM2.5 emissions as required in 40 CFR 51.1008(a)(1)(iv) 
and (a)(2)(iv). The inventories comprehensively address all source 
categories in the Oakridge NAA, actual emissions are provided, and 
appropriate procedures were used to develop the inventories. We are 
therefore proposing to approve the updated 2008 base year worst-case 
day emissions inventory for the Oakridge NAA as meeting the 
requirements of CAA section 172(c)(3) and 40 CFR 51.1008(a)(1), and we 
are proposing to approve the 2015 projected year worst-case day 
inventory for the Oakridge NAA as meeting the requirements of 40 CFR 
51.1008(a)(2). We are also proposing to find that the 2008 base year 
inventory in the Oakridge Update provides an adequate basis for the 
control strategy analysis, the attainment demonstration, and 
demonstrating RFP (discussed in sections II.C, E and F, respectively).

B. Pollutants Addressed

1. Requirements for the Control of Direct PM2.5 and 
Precursors
    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, VOCs and NH3 to 
PM2.5, making them precursors to PM2.5.\5\ 
Formation of secondary PM2.5 may also depend on atmospheric 
conditions, including solar radiation, temperature, relative humidity, 
and the interactions of precursors with preexisting particles and with 
water and ice cloud or fog droplets.\6\
---------------------------------------------------------------------------

    \5\ EPA, Air Quality Criteria for Particulate Matter (EPA/600/P-
99/002aF, October 2004), Chapter 3.
    \6\ EPA, Regulatory Impact Analysis for the Final Revisions to 
the National Ambient Air Quality Standards for Particulate Matter 
(EPA-452/R-12-005, December 2012), p. 2-1.
---------------------------------------------------------------------------

    The EPA interprets the CAA to require states to evaluate sources of 
all four PM2.5 precursors for regulation unless it provides 
a demonstration establishing that it is either not necessary to 
regulate a particular precursor in the nonattainment area at issue in 
order to attain by the attainment date, or that emissions of the 
precursor do not make a significant contribution to PM2.5 
levels that exceed the standard. 40 CFR 51.1006 and 81 FR 58017. The 
EPA has identified SO2, NOX, VOCs, and 
NH3 as precursors to the formation of PM2.5. 40 
CFR 51.1000. Accordingly, the attainment plan requirements 
presumptively apply to emissions of direct PM2.5 and all 
four precursor pollutants from all types of stationary, area, and 
mobile sources, however, the presumption can be rebutted consistent 
with CAA section 189(e) and the EPA's interpretation of the statute.
    Section 189(e) of the CAA 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. By definition, PM10 includes PM2.5. Section 
189(e) contains the only express exception to the control requirements 
under subpart 4 for sources of direct PM2.5 and 
PM2.5 precursor emissions. Notwithstanding the fact that 
section 189(e) explicitly addresses only major stationary sources, the 
EPA interprets the CAA 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 
are not necessary. See 81 FR 58018. If the EPA were to approve a 
state's precursor demonstration, the state would not need to regulate 
emissions of the precursor to meet the requirement to control emissions 
from the inventory to attain as expeditiously as practicable, such as 
the imposition of RACM/RACT on sources of such precursor emissions.
    The state has different options for demonstrating that a particular 
precursor does not need to be controlled in the nonattainment area for 
the purposes of the attainment plan: (1) A comprehensive precursor 
demonstration to establish that the state does not need to address the 
precursor in the attainment plan for purposes of the control strategy, 
RFP, QMs and associated reports, contingency measures, MVEB, or 
regional emissions analyses in transportation conformity 
determinations, and/or (2) a major stationary source precursor

[[Page 52690]]

demonstration supporting a conclusion that one or more precursors do 
not have to be controlled from existing major sources. 40 CFR 51.1006. 
Both types of precursor demonstrations must include a concentration-
based analysis, in which the state evaluates the impact of each 
precursor on ambient PM2.5 levels in the nonattainment area. 
A concentration-based analysis may be sufficient for the EPA to approve 
the demonstration, on a precursor-by-precursor basis. 40 CFR 
51.1006(a)(1). If an impact of a particular precursor cannot be deemed 
insignificant based upon the concentration based analysis, the state 
also has the option of conducting a sensitivity-based analysis to show 
that changes in the emissions of a particular precursor would not 
result in significant changes in ambient PM2.5 in the area, 
notwithstanding the fact that the volume of the precursor at issue is 
large. 40 CFR 51.1006(a)(1)(iii). The EPA's Draft PM2.5 
Precursor Demonstration Guidance (Draft Precursor Demonstration 
Guidance) recommends calculating the precursor impact relative to 
observed ambient data so that the results are applicable to measured 
PM2.5 in the area.\7\
---------------------------------------------------------------------------

    \7\ The Precursor Demonstration Guidance is available at https://www.epa.gov/sites/production/files/2016-11/documents/transmittal_memo_and_draft_pm25_precursor_demo_guidance_11_17_16.pdf
---------------------------------------------------------------------------

2. Direct PM2.5 and Precursors in the Oakridge Update
    In the 2012 Oakridge Attainment Plan and the Oakridge Update, LRAPA 
discusses the five pollutants that contribute to the mass of the 
ambient PM2.5 (i.e., NH3, NOX, 
SO2, VOCs, and direct PM2.5). LRAPA developed the 
2012 Oakridge Attainment Plan before the EPA proposed a new 
implementation rule in 2015 (80 FR 15340, March 23, 2015) and before 
the EPA issued the Draft Precursor Demonstration Guidance in 2016. The 
2012 Oakridge Attainment Plan therefore includes a variety of 
information on precursor impacts on PM2.5 concentrations in 
the Oakridge NAA. However, prior to submitting the Oakridge Update, 
LRAPA was able to take advantage of the final PM2.5 SIP 
Requirements Rule as well as the recommendations in the Draft Precursor 
Demonstration Guidance during the public comment period.
    The Oakridge Update contains information necessary to evaluate a 
comprehensive precursor demonstration for all sources of 
SO2, NOX, NH3, and VOCs. It reports 
speciated PM2.5 data from the WAC monitor that can be 
compared to the recommended insignificance thresholds in the Draft 
Precursor Demonstration Guidance as part of a concentration-based 
analysis. These data are the results of the relative attainment test 
methodology (speciated model attainment test or ``SMAT'') and are 
representative of precursor concentrations for the baseline design 
value of 39.5 [mu]g/m\3\ (Table 4). Values of 0.43 [mu]g/m\3\, 0.17 
[mu]g/m\3\, and 0.17 [mu]g/m\3\ for SO2, NOX, and 
NH3 respectively were compared to the recommended 
insignificance threshold of 1.3 [mu]g/m\3\ in the Precursor 
Demonstration Guidance. LRAPA used the monitored amount of sulfate to 
assess the contribution from SO2 and the amount of ammonium 
+ nitrate to assess the contributions from NOX and 
NH3. LRAPA did not remove background concentrations of the 
PM2.5 species for this analysis. More information on how the 
relative calculations were applied can be found in the Oakridge Update 
section II.D.

                                 Table 4--Concentrations of PM2.5 Species Used for the Speciated Modeled Attainment Test
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                             Elemental                                     Other primary
                Parameter                     Sulfate         Nitrate     Organic carbon      carbon           Water         Ammonium       particulate
--------------------------------------------------------------------------------------------------------------------------------------------------------
Percent.................................             1.1             0.4            88.4             7.6             1.4            0.03             1.1
[mu]g/m\3\..............................            0.43            0.16           34.46            2.95            0.54            0.01            0.44
--------------------------------------------------------------------------------------------------------------------------------------------------------

    LRAPA's VOC precursor demonstration examined both ambient and 
modeled PM2.5 species data to help evaluate the formation of 
secondary organic aerosols (SOA) from VOC emissions in the 
nonattainment area. In the Oakridge Update, LRAPA did not directly 
determine the impact of VOCs on PM2.5 from speciated 
monitoring data alone because it is difficult to distinguish organic 
carbon from direct PM2.5 and secondary organic carbon formed 
from VOC chemistry.
    LRAPA presents several analyses involving observed chemical data, a 
source apportionment analysis, and an independent modeling effort to 
substantiate the demonstration. The PM2.5 data set from 
2006-2010 at the WAC, which formed the basis for the baseline design 
value, shows that exceedances of the standard only occur between 
October 15 and February 28 (See Oakridge Update appendix 3, attachment 
H). The same conclusion is valid for days with concentrations above 25 
[mu]g/m\3\. The results of the concentration-based analysis in Table 4 
show that species commonly associated with photochemistry, ammonium 
sulfate and ammonium nitrate, occur in low concentrations during the 
polluted days. In addition, LRAPA submitted a positive matrix 
factorization (PMF) source apportionment study conducted by the EPA 
Region 10 (See Oakridge Update appendix 3.E.2). That report concluded 
primary emissions of wood smoke was responsible for about 75% of the 
PM2.5 on polluted days above 25 [mu]g/m\3\. Additional 
analysis was conducted by Portland State University in collaboration 
with the ODEQ to better understand the secondary organic aerosols in 
the Klamath Falls, Oregon airshed (See Oakridge Update, page 36). The 
results showed that on wintertime days anthropogenic VOC emissions were 
responsible for 3% of the observed PM2.5. After calibrating 
this value to the Oakridge baseline design value of 39.5 [mu]g/m\3\, 
LRAPA estimated that the anthropogenic VOC contribution to 
PM2.5 is 1.17 [mu]g/m\3\ and asserted that the value is a 
conservatively high value.
3. The EPA's Evaluation and Proposed Action: Pollutants Addressed
    The EPA confirmed that LRAPA performed a contribution-based 
analysis for SO2, NOX, and NH3 
according to section 3.1 of the Draft Precursor Demonstration Guidance, 
with one exception. The guidance recommends that the NOX 
contribution be calculated as the nitrate ion plus the ammonium 
associated with nitrate, whereas LRAPA appears to have included all 
ammonium in the calculation. Rounding to the hundredths decimal place, 
the EPA calculated a contribution of 0.16 [mu]g/m\3\. This difference 
is immaterial to LRAPA's conclusion, and LRAPA's calculation errs on 
the conservative side. The contributions for SO2, 
NOX, and NH3, 0.43 [mu]g/m\3\, 0.17 [mu]g/m\3\, 
and 0.17 [mu]g/m\3\ respectively, are well below the recommended 
contribution

[[Page 52691]]

threshold for the 24-hour PM2.5 NAAQS of 1.3 [mu]g/m\3\.
    For LRAPA's VOC precursor demonstration, the state agency presented 
multiple analyses of observed data, source apportionment modeling, and 
independent modeling. All of the analyses and modeling support the 
conclusion that VOCs contribute only a small amount to PM2.5 
in the Oakridge NAA and that this amount is 1.17 [mu]g/m\3\ or less, as 
indicated by the Portland State University modeling. At the times where 
there is substantial PM2.5 in Oakridge, the temperature is 
low and the sun is relatively weak, which are less conducive to 
secondary PM2.5 formation from VOCs. This conclusion is 
supported by the fact that there is little secondary ammonium sulfate 
and ammonium nitrate in the nonattainment area during periods of high 
pollution (PM2.5 > 25 [mu]g/m\3\).
    While the Portland State University modeling was conducted for 
Klamath Falls, both Klamath Falls and Oakridge were nonattainment for 
the 24-hour PM2.5 standard for mainly wood smoke pollution 
and with similar meteorology and atmospheric chemistry during periods 
of high PM2.5. They are on opposite sides of the Oregon 
Cascade Mountains, but they are only 115 miles apart and the modeling 
used conservative meteorological conditions that would apply to both 
locations. The modeling used emissions that are valid for 2008 in the 
Klamath Falls nonattainment area and correspond to the base year 
emission inventory for the Oakridge Update. The 2008 anthropogenic VOC 
emissions for the Oakridge nonattainment area are 122 tons per year, 
about 5% of that in the Klamath Falls nonattainment area. The EPA 
believes that an analysis with Oakridge emissions would result in a 
much lower PM2.5 contribution from VOCs, as argued by LRAPA 
in the Oakridge Update (See page 36). All of the lines of evidence 
supplied by LRAPA in the Oakridge Update are consistent with the 
PM2.5 contribution from VOCs being 1.17 [mu]g/m\3\ or less. 
This conservative value is below the recommended contribution threshold 
for the 24-hour PM2.5 NAAQS of 1.3 [mu]g/m\3\.
    The EPA also examined an independent regional air quality modeling 
effort for PM2.5, the Airpact model at Washington State 
University.\8\ For 2015, this model estimates all PM2.5, 
including secondary PM2.5 from anthropogenic VOC sources, in 
12-km grid cells across the Northwest on a daily basis. For the period 
of January, February, November, and December, corresponding to the 
Oakridge PM2.5 season, the Airpact model predicts at most 
0.16 [mu]g/m\3\ of PM2.5 species derived from anthropogenic 
VOC emissions. While the model is not conducted in a way to be the 
primary estimate of PM2.5 for the Oakridge nonattainment 
area, its estimate of PM2.5 from anthropogenic VOC emissions 
provides support for the low contribution estimated by Portland State 
University for Klamath Falls and conservatively applied to Oakridge by 
LRAPA.
---------------------------------------------------------------------------

    \8\ http://lar.wsu.edu/airpact/.
---------------------------------------------------------------------------

    Based on a review of the information provided by LRAPA, the EPA 
believes LRAPA's methodology is appropriate for the area and that 
LRAPA's concentration-based analyses are accurate and sufficiently 
comprehensive to establish a precursor demonstration for 
SO2, NOX, NH3, and VOCs. The EPA 
proposes to approve LRAPA's precursor demonstrations for all existing 
sources of SO2, NOX, NH3, and VOCs 
within the Oakridge NAA. As a result, the EPA proposes to find it not 
necessary to evaluate controls on sources of SO2, 
NOX, NH3, and VOCs in the control strategy for 
the Oakridge Update. We discuss LRAPA's evaluation of potential control 
measures for direct PM2.5 in the following section.

C. Reasonably Available Control Measures/Reasonably Available Control 
Technology

1. Requirements for RACM/RACT
    The general SIP planning requirements for nonattainment areas under 
subpart 1 include CAA section 172(c)(1), which requires implementation 
of all RACM, including RACT. The terms RACM and RACT are not further 
defined within subpart 1, but past guidance has described ``reasonable 
available'' controls as those controls that are technologically and 
economically feasible, and necessary for attainment in a given area. 
See 57 FR 13560. The provision explicitly requires that such measures 
must provide for attainment of the NAAQS in the area covered by the 
attainment plan.
    The SIP planning requirements for particulate matter nonattainment 
areas in CAA subpart 4 require states to develop attainment plans that 
implement RACM and RACT on appropriate sources within a nonattainment 
area. Section 189(a)(1)(C) requires that states with areas classified 
as Moderate nonattainment areas have SIP provisions to assure that RACM 
and RACT level controls are implemented by no later than four years 
after designation of the area. As with subpart 1, the terms RACM and 
RACT are not specifically defined within subpart 4, and the provisions 
of subpart 4 do not identify specific control measures that must be 
implemented to meet the RACM and RACT requirements. However, past 
policy has described RACM (including RACT) as those measures that are 
technologically and economically feasible and needed for expeditious 
attainment of the standard. 81 FR 58034. The PM2.5 SIP 
Requirements Rule provides a process for developing an attainment plan 
control strategy for purposes of meeting the RACM and RACT 
requirements.\9\ See 40 CFR 51.1009.
---------------------------------------------------------------------------

    \9\ The development of the RACM and RACT requirements in the 
PM2.5 Implementation Rule was informed by the EPA's 
longstanding guidance in the General Preamble providing 
recommendations for appropriate considerations for determining what 
control measures constitute RACM and RACT for purposes of meeting 
the statutory requirements of subpart 4. See 81 FR 58034.
---------------------------------------------------------------------------

    To meet the Moderate area control strategy requirements, a state 
first needs to identify all sources of direct PM2.5 and 
precursor emissions in the nonattainment area, consistent with common 
emission inventory development practices and requirements. 40 CFR 
51.1009(a)(1). Next, a state must identify existing and potential 
control measures for each identified source or source category of 
emissions. Id. at 51.1009(a)(2). The state's compilation of potential 
control measures must be sufficiently broad to provide a basis for 
identifying all technologically and economically feasible controls that 
may be RACM or RACT. The state must identify potential control measures 
for emissions of direct PM2.5 and each precursor from 
relevant sources unless the state has provided an adequate 
comprehensive demonstration for the nonattainment area at issue showing 
that control of a particular precursor is not required, or provided an 
adequate demonstration with respect to control of precursor emissions 
from existing major stationary sources. Id. at 51.1009(a)(4)(i). For 
any potential control measure identified, a state must evaluate the 
technological and economic feasibility of adopting and implementing 
such measure. Id. at 51.1009(a)(3). For purposes of evaluating 
technological feasibility, a state may consider factors including but 
not limited to operating processes and procedures, raw materials, 
physical plant layout, and potential environmental impacts from the 
adoption of controls. For purposes of evaluating economic feasibility, 
a state may consider factors including but not limited to capital, 
operating and

[[Page 52692]]

maintenance costs and the cost effectiveness of a measure (typically 
expressed in cost per ton of reduction). Id. States should also 
evaluate control measures imposed in other nonattainment areas as RACM 
and RACT as part of this analysis.
    CAA section 110(a)(2)(A) provides generally 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 CAA, which applies 
specifically to nonattainment area plans, imposes comparable 
requirements. Measures necessary to meet RACM/RACT and the additional 
control measure requirements under section 172(c)(6) must be adopted by 
the state in an enforceable form (57 FR 13541) and submitted to the EPA 
for approval into the SIP under CAA section 110.
2. RACM/RACT Analysis in the Oakridge Update
    In the Oakridge Update, LRAPA evaluated and selected control 
measures consistent with the process set forth in 40 CFR 51.1009 that 
constitute RACM/RACT in the Oakridge NAA. Based on emissions inventory 
information and other technical analyses, LRAPA first identified source 
categories in the Oakridge NAA and associated emissions of 
PM2.5 and its precursors. Based on the comprehensive 
precursor demonstration for SO2, NOX, 
NH3, and VOCs, LRAPA limited its RACM/RACT analysis to 
direct PM2.5.
    LRAPA, in coordination with the Oakridge PM2.5 Advisory 
Committee, developed a list of potential control measures for relevant 
sources based on information compiled from various EPA guidance 
documents, and information regarding controls that other states or the 
EPA have identified as RACM or RACT in attainment plans in other 
nonattainment areas. A full discussion of the RACM/RACT analysis and 
control strategies are presented in the Oakridge Update Attainment 
Strategies Section and Appendix 3, Attachment 3.3j. Table 5 provides a 
chart of the RACM/RACT implemented for the Oakridge area and the 
emission reductions modeled for each control strategy. All measures are 
currently being implemented.
    LRAPA's approach to the RACM/RACT analysis targets emissions that 
occur during the wintertime when stagnant air episodes occur and 
concentrations of emissions accumulate, leading to exceedances of the 
2006 24-hour PM2.5 NAAQS. The dominant source of 
PM2.5 in Oakridge on worst-case winter days is wood 
combustion in wood stoves and fireplaces (approximately 86% in the 2008 
base year emissions inventory). Therefore, LRAPA identified strategies 
in the Oakridge Update that focused primarily on RWC emission 
reductions. The long-term permanent RWC strategies consist of a 
mandatory curtailment program, a wood stove changeout program, the 
Oregon and the EPA wood stove certification programs, the Oregon Heat 
Smart Law, and Oregon State and federal transportation and fuel related 
measures.
    LRAPA believes that the implementation of the mandatory curtailment 
program was key in helping this area attain the 24-hour 
PM2.5 standard. The curtailment program restricts wood 
burning on red advisory days through Ordinance 920. Specifically, the 
curtailment restricts combustion in residential solid fuel-fired 
appliances on red advisory days when the forecast is for daily 
PM2.5 to be greater than or equal to 25 [micro]g/m\3\. On 
red advisory days the residents within the City of Oakridge are 
prohibited from emitting visible emissions into the air from solid fuel 
burning devices, unless the device is the sole source of heat or an 
economic need exemption has been granted from the City Administrator. 
The curtailment program is implemented through advisories forecasted by 
LRAPA on a daily basis. The mandatory curtailment program was modeled 
to provide the greatest PM2.5 emissions reductions in the 
NAA of 7.1 [micro]g/m\3\.
    The wood stove changeout programs in Oakridge provided incentives 
for homeowners to replace older uncertified wood stoves with newer, 
cleaner certified wood stoves. Between 2009 and 2012, the changeout 
program replaced 90 uncertified wood stoves in the Oakridge NAA. The 
removal and destruction of the old wood stoves assures emissions 
reductions are permanent. The changeouts are enforceable because a 
statewide building code prohibits the installation of any uncertified 
wood stove in the future. The Heat Smart Program, a statewide mandate 
requiring removal of uncertified wood stoves at the time of home sale, 
went into effect in 2010. This statewide rule closely mirrors the 
existing requirement in the Oakridge ordinance. LRAPA is responsible 
for the implementation of the Heat Smart Program in the Oakridge NAA, 
however, the ODEQ is required to confirm residences where owners 
removed or changed-out uncertified wood stoves upon home sale. Under 
the rule, all uncertified devices on the property being sold must be 
removed at the time of home sale. Three Heat Smart removals were 
recorded and occurred prior to December 31, 2014. The changeout 
programs described above are modeled to collectively provide 
PM2.5 reductions in the NAA of 2.6 [micro]g/m\3\.
    LRAPA applied national and state measures to reduce mobile source 
emissions, such as fuel economy standards and vehicle emissions 
standards including Oregon Low Emission Vehicle regulations (LEV II). 
These mobile measures are modeled to collectively provide direct 
PM2.5 reductions in the NAA of 1.3 [micro]g/m\3\.
    There are two existing industrial sources in the Oakridge area that 
are minor sources of PM2.5 emissions (a portable rock 
crusher and concrete batch plant which shut down in 2014) which 
together emit less than one ton per year of primary PM2.5 
emissions. LRAPA explained that the air pollution control technology 
installed on these sources are standard for the industry and would meet 
RACT requirements. The rock crusher has water-spray controls and the 
concrete plant had baghouse controls. Furthermore, the modeled impact 
of these two sources is much less than 1 [micro]g/m\3\, even if they 
were to operate at maximum permitted production rates valid in 2014. 
LRAPA did not include any RACT requirement for these two minor sources 
in the Oakridge Update because it was determined that RACT was not 
needed to bring the area into attainment.

[[Page 52693]]



 Table 5--RACM/RACT Projected Air Quality Benefit for the Oakridge Area
------------------------------------------------------------------------
                                                           Modeled PM2.5
                                                           reductions on
                                                           a worst-case
                        RACM/RACT                           winter day
                                                            ([micro]g/
                                                               m\3\)
 
------------------------------------------------------------------------
Primary Control Measures:
     Mandatory curtailment program..............             7.1
     Wood stove changeout programs..............  ..............
     OR Heat Smart--uncertified wood stove                   2.6
     removal upon sale of home..........................
     OR and the EPA wood stove certification      ..............
     program............................................
     Transportation and Fuel Related Measures...             1.3
     Diesel Retrofits of school buses...........  ..............
     Oregon's Low Emission Vehicle Program......
     Increased Fuel Economy.....................
                                                         ---------------
        Total...........................................            11.0
Total Effective Reductions *............................            10.2
Ancillary Control Measures:
     Expanded public education..................               0
     Prohibits unseasoned (>20% moisture)         ..............
     firewood...........................................
     Firewood Seasoning Program.................  ..............
     Heating advisory extended from four to       ..............
     eight months.......................................
     Tighter restrictions on the wood stove       ..............
     curtailment exemption process......................
Supplemental Control Measures:
     Expanded field compliance..................  ..............
     Stricter wood stove curtailment program....             1.7
------------------------------------------------------------------------
* The individual emission reduction estimates in this table are derived
  from the modeled Future Design Value in 2015. Because the control
  strategies interact nonlinearly, the total effective reductions value
  is not a simple addition of the individual measures' benefits. When
  all control strategies are simulated together, their benefit is less
  than it would appear because, for instance, the curtailment ordinance
  has a smaller benefit when stoves have already been changed out to be
  cleaner.

    LRAPA expects the ancillary and supplemental control measures, 
listed in Table 5, to increase compliance with regulations and 
encourage behaviors that reduce emissions. The supplemental control 
measures were implemented when it became clear the Oakridge NAA would 
not attain the 2006 24-hr PM2.5 standard by the December 31, 
2015 attainment date. The field compliance improvements were expanded 
in October of 2015 with the hiring of a city code enforcement officer 
to primarily focus on enforcing city ordinances during the winter 
months.
    LRAPA asserts that while the expanded education and outreach is not 
a permanent and enforceable measures in itself, the program to enhance 
education, outreach, and public awareness is key to supporting the 
implementation of the mandatory permanent and enforceable curtailment 
programs, including increasing compliance rates with curtailments on 
red advisory days. Further discussion of these measures can be found in 
the Oakridge Update.
3. The EPA's Evaluation and Proposed Action: RACM/RACT
    The EPA proposes to approve the primary control measures listed in 
Table 5 and sections of the City of Oakridge Ordinance 920 identified 
below in Section IV Proposed Action, regulating wood and other solid 
fuel burning in the Oakridge NAA. LRAPA appropriately followed a 
process to analyze control measures and to select RACM/RACT level 
controls for this specific NAA consistent with the requirement of 
section 172(c)(1) and the procedures for Moderate NAAs identified at 40 
CFR 51.1009. The result of this process was LRAPA's adoption and 
implementation of a control strategy that includes the identified 
technologically and economically feasible control measures for sources 
of direct PM2.5 in the Oakridge NAA. Furthermore, consistent 
with the requirements of 172(c)(6) and the procedures in 40 CFR 
51.1009, LRAPA analyzed control measures to determine if there were any 
other reasonable control measures and found none. The area attained the 
2006 24-hr PM2.5 standard by the December 31, 2016 extended 
attainment date, with a corresponding 2014-2016 design value of 31 
[micro]g/m\3\ in 2016, so the advancement of attainment by one year, or 
as expeditiously as possible, is no longer relevant.
    The EPA proposes to find that the Oakridge Update provides for the 
implementation of RACM/RACT as required by CAA sections 189(a)(1)(C) 
and 172(c)(1). The EPA's evaluation of the Oakridge Update indicates 
that the control strategy includes permanent and enforceable 
requirements and takes appropriate credit for emissions reductions from 
those control measures. The EPA is proposing to approve LRAPA's 
analysis and selection of RACM/RACT as meeting the requirements of 
subparts 1 and 4.

D. Modeling

1. Requirements for Air Quality Modeling
    CAA section 189(a)(1)(B) requires each state with a Moderate 
nonattainment area to submit a plan that includes, among other things, 
either (i) a demonstration (including air quality modeling) that the 
plan will provide for attainment by the applicable attainment date; or 
(ii) a demonstration that attainment by such date is impracticable. For 
model attainment demonstrations, the EPA's modeling requirements are in 
40 CFR part 51, appendix W (82 FR 5182, January 17, 2017). The EPA's 
guidance recommendations for model input preparation, model performance 
evaluation, use of the model output for the attainment demonstration, 
and modeling documentation are described in Draft Guidance for 
Demonstrating Attainment of Air Quality Goals for

[[Page 52694]]

Ozone, PM2.5, and Regional Haze (Modeling Guidance).\10\
---------------------------------------------------------------------------

    \10\ The Modeling Guidance is available on EPA's SCRAM Web site, 
Web page: https://www.epa.gov/scram/state-implementation-plan-sip-attainment-demonstration-guidance; direct link: https://www3.epa.gov/scram001/guidance/guide/Draft_O3-PM-RH_Modeling_Guidance-2014.pdf.
---------------------------------------------------------------------------

    Air quality modeling is used to establish emissions targets, the 
combination of emissions of PM2.5 and PM2.5 
precursors that the area can accommodate and still attain the standard, 
and to assess whether the proposed control strategy is likely to result 
in attainment of the relevant NAAQS. Air quality modeling is performed 
for representative episodes in the past and compared to air quality 
monitoring data collected during those episodes in order to determine 
model performance. To project future design values, the model response 
to emission reductions, in the form of relative response factors, is 
applied on a chemical species-by-species basis to the baseline design 
value, as implemented in the relative attainment test methodology and 
described in the Modeling Guidance. The future year design value is 
intended to estimate the projected 98th percentile of the 24-hour 
average PM2.5 in the attainment year.
    In addition to a modeled attainment demonstration that focuses on 
locations with an air quality monitor, the PM2.5 SIP 
Requirements Rule recommends an additional test called an ``unmonitored 
area analysis.'' This analysis is intended to ensure that a control 
strategy leads to reductions in PM2.5 at other locations 
that have no monitor, but might have base year and/or projected future 
year ambient PM2.5 levels exceeding the standard. This is 
particularly critical where the state and/or the EPA has reason to 
believe that potential violations may be occurring in unmonitored 
areas. Finally, as discussed in the Modeling Guidance, the EPA 
recommends supplemental air quality analyses. These are used as part of 
a weight of evidence analysis, in which the likelihood of attainment is 
assessed by considering evidence other than the main air quality 
modeling attainment test.
    For an attainment demonstration, a thorough review of all modeling 
inputs and assumptions is especially important because the modeling 
must ultimately support a conclusion that the plan (including its 
control strategy) will provide for timely attainment of the applicable 
NAAQS. The EPA recommends that states prepare a modeling protocol in 
order to establish, prior to actual modeling, agreed upon procedures 
with the appropriate EPA Regional Office for all phases of the modeling 
analysis.
2. Air Quality Modeling in the Oakridge Update and the EPA's Evaluation
    LRAPA used a ``linear roll-forward'' model as the basis for 
projecting future design values and the effect of control strategies. 
In the Oakridge Update, this model is referred to as ``a proportional 
roll-back/roll-forward'' and also as a ``rollback model''. We use the 
term roll-forward here but are referring to the same model as in the 
Oakridge Update. A standard roll-forward model assumes all sources 
contribute to the WAC monitor in proportion to their weight in the 
emissions inventory on a species-by-species basis. The model does not 
explicitly treat chemistry leading to secondary PM2.5, but 
as shown earlier, secondary PM2.5 is a very small percentage 
of the total measured PM2.5 in Oakridge. As implemented in 
the Oakridge Update, the roll-forward model assumes that the observed 
concentrations of secondary species (secondary organic aerosol, 
sulfate, nitrate, retained water, and ammonium) remain constant over 
time. For secondary organic aerosol concentrations from VOC precursors, 
LRAPA took Portland State University's results for Klamath Falls and 
applied them to Oakridge.
    LRAPA developed multiple emission inventories for modeling 
attainment, one for the 2008 base year and multiple for the 2015 
attainment year. The inventories used for modeling are the worst-case 
season day as defined in section III.A.2. Because of the simple form of 
the roll-forward model and the small, homogeneous airshed of the 
nonattainment area, the planning inventory for the nonattainment area 
did not need to be expanded or modified for use as an inventory for 
modeling. The projected 2015 attainment year inventory accounts for all 
changes (i.e. vehicle fleet turnover, population changes) that were 
expected to occur from 2008 through December 31, 2014. LRAPA then 
applied each local control strategy to the projected 2015 modeling 
inventory in isolation, and several or all strategies jointly, in order 
to develop emission inventories for various emission control scenarios 
in the 2015 attainment year. Once the emission inventories were 
available, they were input into the relative attainment test to 
estimate the future year design value.
    To calculate the projected 2015 PM2.5 design value, 
LRAPA performed the SMAT methodology, as recommended in the EPA 
modeling guidance. LRAPA used the ratio of attainment year (2015) to 
base year (2008) modeling results to derive relative response factors 
for organic carbon, elemental carbon, and ``other PM2.5'' 
(mainly crustal material). The relative response factor for organic 
carbon does not account for changes in secondary organic aerosol, as 
estimated by Portland State University, because secondary organic 
aerosol is held constant between the base year and the attainment year 
(2015). The concentration of secondary species sulfate, nitrate, 
retained water, and ammonium are held constant between the base year 
and the attainment year (2015), and thus those species have a response 
factor of 1. These response factors were applied to concentrations of 
chemical species in the baseline design value to produce an attainment 
year design value. The results of this process are further discussed in 
the Attainment Demonstration section E. Details of the analysis are 
presented in Appendix 3, Attachment H of the Oakridge Update.
    LRAPA chose the 2006-2010 period for the baseline to represent 
conditions before emission controls and calculated a baseline design 
value of 39.5 [mu]g/m\3\. The concentrations of chemical species used 
in the baseline design value were drawn from the monitoring data for 
the top 25 percent most polluted wintertime days (in the first and 
fourth quarters) when speciated monitoring was collected (between July 
2009 and July 2011). Only the top 25 percent was used because there are 
many cleaner days in the winter when the emission source mix and 
contributions of PM2.5 to the monitor are not relevant for 
air quality planning to meet the 24-hour PM2.5 standard. The 
top 25 percent most polluted wintertime days best captured the days 
with weather conditions and emissions patterns that occur when the 
standard is exceeded. The average of the speciated concentrations of 
the top 25 percent most polluted days were weighted to the observed 
PM2.5 concentrations from the official regulatory data at 
the WAC, such that the speciated PM2.5 data used for air 
quality modeling (and for the precursor demonstration) are reflective 
of the baseline design value of 39.5 [mu]g/m\3\. The technique was not 
used for the second and third quarters because an examination of the 
PM2.5 data from the baseline period 2006-2010 showed that 
the data from the second and third quarters were too low to affect the 
attainment year design value.
    The Oakridge Update also contains an unmonitored area analysis and 
supplemental information as additional support for the modeling 
demonstration. LRAPA conducted a saturation study in

[[Page 52695]]

2002-2003 in the town of Oakridge and in 2009-2010 for the Westfir 
portion of the nonattainment area (See Oakridge Update appendix 3.A). 
The area around the WAC had the highest concentrations of 
PM2.5 in the winter when the air was polluted. LRAPA 
submitted a positive matrix factorization (PMF) source apportionment 
study conducted by the EPA Region 10 (See Oakridge Update appendix 
3.E.2). That report concluded that primary emissions of wood smoke was 
responsible for about 75% of the PM2.5 on polluted days 
above 25 [mu]g/m\3\. In comparison, the base year emission inventory 
attributes 80% of the primary PM2.5 on Worst Case Days to 
wood smoke.
3. The EPA's Conclusions on Air Quality Modeling
    The model inputs, model design, modeling emission inventories, 
supplemental information, and attainment test methodology are 
appropriate for nonattainment planning and for an attainment 
demonstration in the Oakridge NAA. The roll-forward model used by LRAPA 
is not the standard attainment model used in larger areas and in areas 
with significant secondary PM2.5. However, the roll-forward 
model is well-suited to a nonattainment area that is on the scale of 5-
10 km and to an area where secondary PM2.5 is limited. The 
extra complexity of a gridded photochemical model would add little 
value and may be less transparent and more difficult to use for testing 
out RACT/RACM measures. LRAPA's unmonitored area analysis shows that a 
roll-forward model based on the data and location of the WAC is 
appropriate because other parts of the nonattainment area experience 
lower PM2.5 concentrations on polluted winter days. By 
keeping the PM2.5 concentration of sulfate, nitrate, 
retained water, and ammonium the same in 2015 as in 2008, LRAPA is 
estimating a conservatively high attainment year design value because 
the emission inventories show that precursor emissions to those 
secondary species went down between 2008 and 2015, sometimes 
substantially (See Tables 2 and 3 in section III.A.2). If secondary 
PM2.5 reductions were included in the model, the modeled 
future year design value would be slightly lower.
    The EPA is proposing to find that LRAPA's model adequately meets 
the current EPA modeling requirements, and uses acceptable modeling 
techniques to demonstrate attainment by December 31, 2015. The EPA also 
proposes to find that the modeling is adequate for purposes of 
supporting the control strategy analysis, RFP, and contingency 
measures.

E. Attainment Demonstration

1. Requirements for Attainment Demonstration
    CAA section 189(a)(1)(B) requires that each Moderate area 
attainment plan include a demonstration that the plan provides for 
attainment by the latest applicable Moderate area deadline or, 
alternatively, that attainment by the latest applicable attainment date 
is impracticable. A demonstration that the plan provides for attainment 
must be based on air quality modeling consistent with the EPA's 
modeling regulations (51.1011(a)(2); 51.1011(a)(4)(ii); and 81 FR 
58049). In SIP submissions to demonstrate attainment, the state should 
document that its required control strategy in the plan represents the 
application of RACM/RACT to existing sources.
    CAA section 188(c) states, in relevant part, that the Moderate area 
attainment date ``shall be as expeditiously as practicable but no later 
than the end of the sixth calendar year after the area's designation as 
nonattainment.'' For the 2006 24-hour PM2.5 NAAQS, effective 
December 14, 2009, the applicable Moderate area attainment date under 
section 188(c) for the Oakridge NAA is as expeditiously as practicable, 
but no later than December 31, 2015.
    In addition, the EPA's August 24, 2016, PM2.5 SIP 
Requirements Rule provides that a state's modeled attainment 
demonstration needs to establish that an area will attain the NAAQS by 
the projected attainment date. Practically speaking, this is considered 
satisfied by the modeling showing that the 98th percentile is below the 
standard for the attainment year (81 FR 58010, at page 58054). The EPA 
authorizes this approach because of the potential availability of 
extensions of the attainment date under relevant provisions of the CAA. 
In other words, if ambient data show attainment-level concentrations in 
the applicable statutory attainment year, a state may be eligible for 
up to two 1-year extensions of the attainment date. See 40 CFR 51.1005. 
Using this provision, a state may be able to attain the NAAQS by the 
December 31, 2016 extended attainment date, even if the measured design 
value (a 3-year average) for an area does not meet the NAAQS by the end 
of the 6th calendar year after designation. For this reason, the EPA's 
PM2.5 SIP Requirements Rule indicates that it is acceptable 
for a state to model air quality levels for the final statutory 
attainment year in which the area is required to attain the standard 
(in this case 2015).
2. Attainment Demonstration in the Oakridge Update
    In the Attainment Demonstration section of the Oakridge Update, 
LRAPA described how its chosen control strategies would provide the 
emissions reductions needed to demonstrate attainment by December 31, 
2015. The majority of projected control strategy air quality benefits 
came from the wood smoke curtailment program, the wood stove changeout 
program, and the Heat Smart program. A more detailed discussion of 
these strategies can be found in section III. C. RACT/RACM above.
    Table 6 lists the control strategies, the modeled PM2.5 
benefit in the attainment year from each major control strategy, and 
the attainment year design value from all control strategies 
implemented together. LRAPA estimated the total effective emissions 
reductions from the adopted control strategy in the Oakridge Update 
would result in a 10.2 [micro]g/m\3\ reduction from the baseline design 
value of 39.5 [mu]g/m\3\ at the WAC monitor resulting in a 2015 
attainment year design value of 29.3 [micro]g/m\3\. The design value 
represents the modeled 98th percentile for 2015 based on controls in 
place by December 31, 2014.

 Table 6--2015 Attainment Demonstration Strategies for the Oakridge Area
------------------------------------------------------------------------
                                                              Projected
                                                             air quality
                     Control strategies                        benefit
                                                              ([micro]g/
                                                                m\3\)
------------------------------------------------------------------------
Baseline Design Value......................................         39.5
Primary Control Measures (Table 5 contains a detailed list          10.2
 of control strategies)....................................

[[Page 52696]]

 
Future Design Value 2015...................................         29.3
------------------------------------------------------------------------
* The individual emission reduction estimates in this table are derived
  from the modeled Future Design Value in 2015. The air quality benefit
  for the control measures are presented in Table 5. Because the control
  strategies interact nonlinearly, the final design value is not a
  simple subtraction of the individual measures' benefits from the
  baseline design value. When all control strategies are simulated
  together, their benefit is less than it would appear because, for
  instance, the curtailment measure has a smaller benefit when stoves
  have been changed out to be cleaner.

3. The EPA's Evaluation and Proposed Action: Attainment Demonstration
    We have evaluated the Oakridge attainment demonstration, supporting 
air quality modeling, supplemental analyses, and RACM/RACT control 
strategy analyses which address the adoption of all reasonable 
measures. The EPA's evaluation of the Oakridge Update indicates that 
the control strategy includes permanent and enforceable requirements 
and takes appropriate credit for emissions reductions from those 
control measures. We are proposing to approve the Oakridge attainment 
demonstration for the area. LRAPA showed that emission controls were in 
place in order to demonstrate attainment by December 31, 2015 for the 
2006 PM2.5 NAAQS. The requirement to demonstrate that 
attainment could not be advanced by a year or more by implementing 
additional measures as expeditiously as practicable was met in that 
there were no additional reasonable control measures available for 
implementation.
    The area needed to identify at least 4.1 [micro]g/m\3\ of 
reductions to get from the baseline design value of 39.5 [mu]g/m\3\ to 
attain the 2006 PM2.5 NAAQS. With a 2014-2016 design value 
of 31 [micro]g/m\3\, the emissions reductions from the implementation 
of the adopted permanent and enforceable measures of 10.2 [micro]g/m\3\ 
are sufficient to provide a buffer below the 35 [micro]g/m\3\ standard 
and demonstrate attainment. Recent monitoring data demonstrates 
attainment with the NAAQS and that the plan was effective.
    Finally, the unmonitored area analysis confirms that the WAC is the 
highest neighborhood-scale location in the nonattainment area on 
polluted winter days. Given the high contribution of wood smoke to high 
PM2.5 levels at the WAC monitor, the relatively uniform 
distribution of emissions within the nonattainment area, and the focus 
of control measures on wood burning, it is reasonable to conclude that 
demonstrating attainment at the WAC monitor assures attainment 
elsewhere in the nonattainment area.

F. Reasonable Further Progress (RFP) and Quantitative Milestones (QM)

1. Requirements for RFP and QMs
    CAA section 172(c)(2) requires nonattainment area plans to provide 
for RFP. In addition, CAA section 189(c) requires PM2.5 
nonattainment area SIPs to include QMs to be achieved every 3 years 
until the area is redesignated to attainment and which demonstrate RFP. 
CAA section 171(1) defines RFP as ``such annual incremental reductions 
in emissions of the relevant air pollutant as are required by [Part D] 
or may reasonably be required by the Administrator for the purpose of 
ensuring attainment of the applicable [NAAQS] by the applicable date.'' 
Neither subpart 1 nor subpart 4 require that a set percentage of 
emissions reductions be achieved in any given year for purposes of 
satisfying the RFP requirement for PM2.5 NAAQS. Because RFP 
is an annual emission reduction requirement and the QMs are to be 
achieved every 3 years, when a state demonstrates compliance with the 
QM requirement, it provides an objective evaluation of RFP that has 
been achieved during each of the relevant 3 years. 40 CFR 
51.1013(a)(1)(ii).
    An attainment plan for a PM2.5 nonattainment area must 
include an RFP analysis that demonstrates that sources in the area will 
achieve such annual incremental reductions in emissions of direct 
PM2.5 and PM2.5 precursors as are necessary to 
ensure attainment as expeditiously as practicable. 40 CFR 51.1012(a). 
The RFP analysis must include a schedule for implementation of the 
control measures and provide projected emissions from these measures 
for each applicable milestone year. Id. at 51.1012(a)(1)-(2). At a 
minimum, QMs for a Moderate area attainment plan must track progress 
achieved in implementing RACM/RACT and additional reasonable control 
measures by each milestone date. Therefore, timely implementation of 
the control measures that achieve the emissions reductions comprising 
the RFP plan provides a means for satisfying the QM requirement.
    The CAA does not specify the starting point for counting the 3-year 
periods for QMs under CAA section 189(c). However, the EPA's 
longstanding interpretation of the CAA is that the first QM should fall 
3 years after the latest date on which the state should have submitted 
the attainment plan. For the 2006 PM2.5 NAAQS, the EPA set 
QMs to be achieved no later than 3 years after December 31, 2014, and 
every 3 years thereafter until the QM date that falls within 3 years 
after the applicable attainment date. 40 CFR 51.1013(a)(4). 
Accordingly, the only QM date for the Oakridge NAA Moderate attainment 
plan must be met no later than December 31, 2017 (3 years after 
December 31, 2014), with additional QM dates to be identified in the 
Serious attainment plan if needed.
2. RFP and QMs in the Oakridge Update
    The Oakridge Update identifies direct PM2.5 emission 
reductions achieved as a result of progressively implemented control 
strategies. These control strategies were implemented from 2008 through 
2016 and continue to be in effect. LRAPA provided a table in the 
Oakridge Update that listed the PM2.5 control strategies, 
the implementation timeframes and direct PM2.5 emissions 
reductions realized. Table 7 summarizes this information.

[[Page 52697]]



                     Table 7--Summary of PM2.5 Air Quality Improvements From RWC Strategies
----------------------------------------------------------------------------------------------------------------
                                                                     Reductions on worst case
                                                                     winter days- direct PM2.5
                          RWC strategy                           --------------------------------   Time period
                                                                      lb/day       [micro]g/m\3\
----------------------------------------------------------------------------------------------------------------
Changeouts......................................................              38             2.6       2009-2014
Curtailment Program.............................................             107             7.1       2009-2014
Strengthened Curtailment Program................................              25             1.7       2015-2016
----------------------------------------------------------------------------------------------------------------

    LRAPA provided a projected year emissions inventory and modeled 
concentrations for 2016 which is within the three-year period after the 
applicable attainment date (3 years after December 31, 2014). The 2016 
projected emissions inventory and modeling reflects the contingency 
measures implemented in 2015 in order to meet the 2006 24-hr 
PM2.5 standard by the December 31, 2016 extended attainment 
date. The demonstrated impact of these measures (stronger curtailment 
program and enhanced enforcement on more red advisory days) showed a 
reduction in PM2.5 emissions by an additional 25 lb/day and 
a reduction in PM2.5 concentrations on worst case days by an 
additional 1.7 [micro]g/m\3\. The modeled PM2.5 
concentration for 2016 was 27.5 [micro]g/m\3\ and the actual 98th 
percentile for 2016 was 21.7 [micro]g/m\3\.
    In the Oakridge Update, LRAPA outlined their plan to submit to the 
EPA, by June 30, 2017, a Quantitative Milestone report and an annual 
RFP update in the event the standard was not attained by December 31, 
2016. The QM report would explain ongoing progress in implementing the 
required control measures in the area until attainment of the 2006 24-
hr PM2.5 NAAQS was achieved.
3. The EPA's Evaluation and Proposed Action: RFP and QMs
    The EPA proposes to find that the Oakridge Update adequately meets 
both the RFP and QM requirements for this area as specified in the CAA 
and the PM2.5 SIP Requirements Rule. Even though LRAPA did 
not label the information we relied on to make our determination as RFP 
and QM, it was clear that attainment was achieved incrementally and the 
area substantively met the RFP and QM requirements based on other data 
gathered from their submission.
    As of the time the state submitted the Oakridge Update, the area 
was attaining the 2006 24-hour PM2.5 NAAQS. After reviewing 
the Oakridge Update, the EPA identified that the control strategies 
were implemented on time and achieved incremental emission reductions 
that resulted in attainment of the 2006 24-hour PM2.5 NAAQS 
by the extended attainment date. The Oakridge Update provides 
sufficient data to identify emission reductions necessary for 
quantifying reasonable progress towards demonstrating attainment. The 
key control strategies for attainment were implemented and emissions 
reductions achieved during the period of nonattainment as a result of 
measures implemented in the area. These measures collectively 
contributed to the attainment of the 2006 PM2.5 NAAQS by 
December 31, 2016. As a result, the area needs no further annual 
incremental emissions reductions.
    The EPA finds that the adopted measures listed in Table 7 are being 
implemented and sufficient incremental reductions in emissions occurred 
over the attainment period to satisfy the RFP requirement. Further, the 
EPA concludes that the accounting of control measure implementation and 
the resultant emissions reductions satisfy the QM requirement for the 
area. For these reasons, the EPA proposes to approve the submitted 
Oakridge Update as meeting both the RFP and QM requirements.
    The requirement to submit and achieve milestones does not continue 
after attainment of the NAAQS. Although section 189(c) states that 
revisions shall contain milestones which are to be achieved until the 
area is redesignated to attainment, such milestones are designed to 
show reasonable further progress ``toward attainment by the applicable 
attainment date,'' as defined by section 171. Thus, it is clear that 
once the area has attained the standard, a demonstration to satisfy the 
QM requirement is no longer necessary. This interpretation is supported 
by language in section 189(c)(3), which mandates that a state that 
fails to achieve a milestone must submit a plan that assures that the 
state will achieve the next milestone or attain the NAAQS if there is 
no next milestone.

G. Contingency Measures

1. Requirements for Contingency Measures
    Under CAA section 172(c)(9), PM2.5 plans must include 
contingency measures to be implemented if an area fails to meet RFP or 
fails to attain the PM2.5 standards by the applicable 
attainment date. The purpose of contingency measures is to continue 
progress in reducing emissions during the period while a state is 
revising its SIP to address a failure, such as a failure to meet a QM 
requirement or failure to attain. The principal considerations for 
evaluating contingency measures are:
     Contingency measures must be fully adopted rules or 
control measures that are ready to be implemented quickly upon failure 
to meet RFP or failure of the area to meet the NAAQS by its attainment 
date.
     The SIP must contain trigger mechanisms for the 
contingency measures, specify a schedule for implementation, and 
indicate that the measures will be implemented without further action 
by the state or by the EPA. In general, we expect all actions needed to 
affect full implementation of the measures to occur within 60 days 
after the EPA notifies the state of a failure.
     The contingency measures shall consist of control measures 
that are not otherwise included in the control strategy or that achieve 
emissions reductions not otherwise relied upon in the control strategy 
for the area.
     The measures should provide for emissions reductions 
equivalent to approximately one year of reductions needed for RFP 
calculated as the overall level of reductions needed to demonstrate 
attainment divided by the number of years from the base year to the 
attainment year. 81 FR 58066.
2. Contingency Measures in the Oakridge Update
    In 2014, LRAPA determined the Oakridge NAA was not making 
reasonable further progress toward attaining the 2006 24-hr 
PM2.5 NAAQS by the December 31, 2015, attainment date. In 
addition to requesting a 1-year

[[Page 52698]]

extension of the 2015 attainment date, LRAPA and the City of Oakridge 
triggered the following contingency measures contained in the 2012 
p.m.2.5 SIP submittal.\11\
---------------------------------------------------------------------------

    \11\ These contingency measures were previously disapproved by 
EPA (81 FR 72714) because the regulatory text of the contingency 
measures (Oakridge Ordinance 914) had not been included as a part of 
that SIP submission.
---------------------------------------------------------------------------

     A stricter advisory program, reducing the red advisory 
threshold by 5 [mu]g/m\3\, from 30 [mu]g/m\3\ to 25 [mu]g/m\3\ thereby 
potentially increasing the average number of red advisory days by 5 
days per year--adopted into Oakridge Ordinance 920.
     Expanding field compliance with a dedicated Oakridge 
Police Department compliance officer.
    The contingency measures for stronger enforcement on more red 
advisory days were modeled and projected to reduce the future year 
design value by 1.7 [micro]g/m\3\, which is greater than the one year 
of RFP reductions of 0.7 [micro]g/m\3\ needed per year to demonstrate 
attainment by the attainment year.\12\ These contingency measures are 
fully implemented, submitted as part of the permanent and enforceable 
control strategy in the Oakridge Update (Oakridge Ordinance 920) and 
have helped the area achieve attainment by 2016.
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    \12\ Other provisions were adopted in Ordinance 920, but weren't 
relied upon as contingency measures to establish the one year of RFP 
reduction needed per year to demonstrate attainment by the 
attainment year.
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    In order to address the next potential triggering event, failure to 
attain the applicable standard, LRAPA identified two additional 
contingency measures and submitted them as part of the Oakridge Update. 
In accordance with basic requirements for valid contingency measures, 
these two measures are not required to meet other attainment plan 
requirements and are not relied on in the control strategy. The 
contingency measures in the Oakridge Update are:
     An increase in the number of red advisory days each 
winter. LRAPA projects that by reducing the red advisory thresholds by 
3 [mu]g/m\3\, from 25 [mu]g/m\3\ to 22 [mu]g/m\3\, the average number 
of potential red advisory days will increase by three to five 
additional days per year; and
     Prohibition of fireplace use on yellow advisory days (in 
addition to the existing prohibition on red advisory days).
    These contingency measures were adopted as part of the City of 
Oakridge Ordinance 920. In accordance with basic requirements for valid 
contingency measures, they will go into effect for the October 1, 2017, 
wood heating season with minimal further action by the state or the EPA 
in response to a triggering event; in this case the measures adopted by 
LRAPA will automatically go into effect if the EPA makes a finding that 
Oakridge fails to attain by the applicable attainment date. 
Implementation of the contingency measures are projected to reduce the 
future year design value by 2.8 [micro]g/m\3\, which is greater than 
the one year of RFP reductions of 0.7 [micro]g/m\3\ needed per year to 
demonstrate attainment by the attainment year.
3. The EPA's Evaluation and Proposed Action: Contingency Measures
    The Oakridge Update includes contingency measures that would take 
effect upon failure of the Oakridge NAA to attain by the applicable 
attainment date, December 31, 2016. The Oakridge NAA monitored 
attainment of the 2006 24-hour PM2.5 NAAQS by the applicable 
attainment date. In this notice, the EPA is proposing to approve the 
contingency measures included within the Oakridge Ordinance 920 as 
meeting the requirements of section 176(c) of the CAA.

H. Motor Vehicle Emissions Budgets

1. Requirements for the Motor Vehicle Emissions Budgets
    Section 176(c) of the CAA requires Federal actions in nonattainment 
and maintenance areas to ``conform to'' the goals of SIPs. This means 
that such actions will not cause or contribute to violations of a 
NAAQS, worsen the severity of an existing violation, or delay timely 
attainment of any NAAQS or interim milestones. Actions involving 
Federal Highway Administration (FHWA) or Federal Transit Administration 
(FTA) funding or approval are subject to the transportation conformity 
rule (40 CFR part 93, subpart A) as well as the Oregon transportation 
conformity SIP which cites the national rule (77 FR 60627). Under this 
rule, metropolitan planning organizations (MPOs) in nonattainment and 
maintenance areas coordinate with state air quality and transportation 
agencies, the EPA, the FHWA and the FTA to demonstrate that their long-
range transportation plans and transportation improvement programs 
(TIPs) conform to applicable SIPs. This demonstration is typically 
determined by showing that estimated emissions from existing and 
planned highway and transit systems are less than or equal to the motor 
vehicle emissions budgets (MVEB) contained in a SIP.
    The emissions inventories should identify MVEB for the attainment 
year and each RFP milestone year for direct PM2.5 and 
NOX. The MVEB should also reflect VOC, SO2, and 
NH3, if transportation-related emissions of these precursors 
have been found to contribute significantly to the PM2.5 
nonattainment problem (40 CFR 93.102(b)(2)(iv)). All direct 
PM2.5 SIP budgets should include direct PM2.5 
motor vehicle emissions from tailpipe, brake wear, and tire wear. A 
state must also consider whether re-entrained paved and unpaved road 
dust are significant contributors and should be included in the direct 
PM2.5 budget. See 40 CFR 93.102(b) and 93.122(f) and the 
conformity rule at https://nepis.epa.gov/Exe/ZyPDF.cgi/P100E7CS.PDF?Dockey=P100E7CS.PDF.
2. Motor Vehicle Emissions Budgets in the Oakridge Update
    Oakridge is considered an isolated rural nonattainment area, so 
transportation conformity under 40 CFR 93.109(g) is only needed when a 
non-exempt federally-funded project is funded or approved. The Oakridge 
Update includes budgets for direct PM2.5 for 2015. The 
budget was calculated with the assistance of the ODEQ using the 
MOVES2014a vehicle emissions model and was executed with locally 
developed inputs representative of wintertime calendar year 2015 
conditions. The mobile source emissions were modeled to steadily 
decrease between 2008 and 2015 as a result of cleaner vehicles and 
cleaner fuels. Secondary particulate is a minor contributor to the 
Oakridge PM2.5 air pollution concentrations on worst winter 
days as summarized above in section III. B. Therefore, the Oakridge 
2015 MVEB of 22.2 lb/day for direct PM2.5 is a sum of 
primary exhaust, brake wear and tire wear.
3. The EPA's Evaluation and Proposed Action: Motor Vehicle Emissions 
Budgets
    For MVEB to be approvable, they must meet, at a minimum, the EPA's 
adequacy criteria (40 CFR 93.118(e)(4)). In this notice, the EPA is 
proposing to approve the comprehensive precursor demonstration for 
SO2, NOX, NH3, and VOCs (See section 
III. B) and proposing to find that the state does not need to address 
precursors in the Oakridge Update for purposes of the MVEB, or regional 
emissions analyses in transportation conformity determinations. The EPA 
has reviewed the MVEB and found it to be consistent with the attainment 
of the 2006 24-hour PM2.5 NAAQS and that it met the

[[Page 52699]]

criteria for adequacy and approval (82 FR 26090, June 6, 2017). The EPA 
proposes to approve the 2015 MVEB of 22.2 lb/day for direct 
PM2.5 for the 24-hour PM2.5 NAAQS for the 
Oakridge NAA. As a clarification, only the 2015 MVEB in the submittal 
is applicable to the attainment plan and only the 24-hour budget will 
be used for conformity purposes. As such, the EPA believes that these 
motor vehicle emissions meet applicable requirements for such budgets 
for purposes of the 2006 24-hour PM2.5 NAAQS for 
transportation conformity purposes. If approved as proposed, this 
action will lift the conformity freeze put in place as of November 21, 
2016 (40 CFR 72714).

IV. Proposed Action

    The EPA proposes to:
     Determine that the Oakridge area attained the 2006 24-hour 
PM2.5 NAAQS by the December 31, 2016 attainment date as 
demonstrated by quality-assured and quality-controlled 2014-2016 
ambient air monitoring data.
     Make a clean data determination (CDD) in accordance with 
the EPA's clean data policy. In the event that EPA determines in its 
final action that the Oakridge Update should not be approved, the Clean 
Data Determination would suspend Oregon's obligation to submit a 
revised SIP to address the attainment planning requirements related to 
attainment of the 2006 24-hour PM2.5 NAAQS, and would toll 
the FIP and sanctions clocks that were started by the EPA's prior 
disapprovals as long as the area remains in attainment.
     Fully approve the remaining elements of the Oakridge 
Update as meeting the requirements section 110(k) of the CAA. 
Specifically, the EPA has determined the Oakridge Update meets the 
substantive statutory and regulatory requirements for base year and 
projected emissions inventories for the nonattainment area, and an 
attainment demonstration with modeling analysis and imposition of RACM/
RACT level emission controls, RFP plan, QMs, and contingency measures. 
Therefore, the EPA is proposing to approve these elements.\13\ The EPA 
is also proposing to approve a comprehensive precursor demonstration 
for VOCs, SO2, NOX, and NH3. The EPA 
is also proposing to approve the 2015 MVEB of 22.2 lb/day for direct 
PM2.5.
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    \13\ It is important to note, the 2016 Oakridge Update includes 
the complete 2012 Oakridge Attainment Plan which was previously 
partially approved, partially disapproved (81 FR 72714). In this 
action, the EPA is taking no action on the following elements of 
2012 Oakridge Attainment Plan included in Appendix 3 of the 2016 
Oakridge Update; the 2012 Oakridge PM2.5 Attainment Plan 
and associated appendices F1, F6 and K. These elements are 
considered informational elements, not essential for making 
decisions on the 2016 Oakridge Update. On February 24, 2016, ODEQ 
withdrew appendices F2 and F3 from the Oakridge PM2.5 
Attainment Plan submittal and clarified that they were provided for 
informational purposes only.
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     Approve, and incorporate by reference, the following 
sections in the City of Oakridge Ordinance 920: Section 1 Definitions; 
Section 2(1) Curtailment; Section 2(2) Prohibited materials; Section 3 
Solid Fuel Burning Devices Upon Sale of the Property; Section 4 Solid 
Fuel Burning Devices Prohibited; Section 5 Solid Fuel Burning Devices 
Exemptions; Section 7 Contingency Measures.

V. Incorporation by Reference

    In this rule, we are proposing to include in a final rule 
regulatory text that includes incorporation by reference. In accordance 
with requirements of 1 CFR 51.5, we are proposing to incorporate by 
reference the provisions described above in Section IV. Proposed 
Action. The EPA has made, and will continue to make, these documents 
generally available electronically through https://www.regulations.gov 
and/or in hard copy at the appropriate EPA office (see the ADDRESSES 
section of this preamble for more information).

VI. Statutory and Executive Order Reviews

    Under the CAA, the Administrator is required to approve a SIP 
submission that complies with the provisions of the CAA 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 CAA. Accordingly, this 
proposed action merely approves state law as meeting Federal 
requirements and does not impose additional requirements beyond those 
imposed by state law. For that reason, 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 CAA; and
     Does not provide the EPA with the discretionary authority 
to address, as appropriate, disproportionate human health or 
environmental effects, using practicable and legally permissible 
methods, under Executive Order 12898 (59 FR 7629, February 16, 1994).
    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 
rule does not have tribal implications as specified by Executive Order 
13175 (65 FR 67249, November 9, 2000), nor will it impose substantial 
direct costs on tribal governments or preempt tribal law.

List of Subjects in 40 CFR Part 52

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

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

    Dated: November 1, 2017.
Michelle L. Pirzadeh,
Acting Regional Administrator, Region 10.
[FR Doc. 2017-24539 Filed 11-13-17; 8:45 am]
 BILLING CODE 6560-50-P