[Federal Register Volume 91, Number 93 (Thursday, May 14, 2026)]
[Proposed Rules]
[Pages 27224-27229]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2026-09604]


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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Parts 52 and 81

[EPA-R09-OAR-2026-2608; FRL-13323-01-R9]


Determination of Attainment by the Attainment Date and Clean Data 
Determination for the 2012 Annual Fine Particulate Standard; Plumas 
County, California

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.

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SUMMARY: The Environmental Protection Agency (EPA) is proposing to 
determine that the Portola nonattainment area in Plumas County, 
California, attained the 2012 annual fine particulate matter 
(``PM2.5'') national ambient air quality standard (NAAQS or 
``standard'') by the December 31, 2025 ``Serious'' area attainment 
date. This proposed determination is based on ambient air quality 
monitoring data from 2023 through 2025. We are also proposing to make a 
clean data determination (CDD) based on the 2023 through 2025 data. If 
we finalize this CDD, certain Clean Air Act (CAA) requirements that 
apply to the Portola nonattainment area will be suspended for so long 
as the area continues to meet the 2012 annual PM2.5 NAAQS. 
The area would remain designated nonattainment for the 2012 annual 
PM2.5 NAAQS, unless and until the State submits, and EPA 
approves, a redesignation request and maintenance plan for the area. We 
are taking comments on this proposal and plan to follow with a final 
action.

DATES: Comments must be received on or before June 15, 2026.

ADDRESSES: Submit your comments, identified by Docket ID No. EPA-R09-
OAR-2026-2608 at https://www.regulations.gov. For comments submitted at 
Regulations.gov, follow the online instructions for submitting 
comments. Once submitted, comments cannot be edited or removed from

[[Page 27225]]

Regulations.gov. The EPA may publish any comment received to its public 
docket. Do not submit electronically any information you consider to be 
Confidential Business Information (CBI) or other information whose 
disclosure is restricted by statute. Multimedia submissions (audio, 
video, etc.) must be accompanied by a written comment. The written 
comment is considered the official comment and should include 
discussion of all points you wish to make. The EPA will generally not 
consider comments or comment contents located outside of the primary 
submission (i.e., on the web, cloud, or other file sharing system). For 
additional submission methods, please contact the person identified in 
the FOR FURTHER INFORMATION CONTACT section. For the full EPA public 
comment policy, information about CBI or multimedia submissions, and 
general guidance on making effective comments, please visit https://www.epa.gov/dockets/commenting-epa-dockets. If you need assistance in a 
language other than English or if you are a person with a disability 
who needs a reasonable accommodation at no cost to you, please contact 
the person identified in the FOR FURTHER INFORMATION CONTACT section.

FOR FURTHER INFORMATION CONTACT: Lindsay Wickersham, Planning Section 
(AIR-2-1), EPA Region IX, 75 Hawthorne Street, San Francisco, CA 94105; 
telephone number: (415) 947-4192; email address: 
[email protected].

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

Table of Contents

I. Background
    A. The 2012 Annual PM2.5 NAAQS
    B. CAA Requirements for PM2.5 Nonattainment Areas
    C. Portola Nonattainment Area Designation for the 2012 
PM2.5 NAAQS and SIP Actions
    D. CAA Requirement for a Determination of Attainment
    E. The EPA's Clean Data Policy
II. Proposed Determination of Attainment
    A. Applicable Statutory and Regulatory Provisions
    B. Monitoring Network Review, Quality Assurance, and Data 
Completeness
    C. The EPA's Evaluation of Attainment
III. Proposed Clean Data Determination
IV. The EPA's Proposed Action
V. Statutory and Executive Order Reviews
    A. Executive Order 12866: Regulatory Planning and Review and 
Executive Order 13563: Improving Regulation and Regulatory Review
    B. Executive Order 14192: Unleashing Prosperity Through 
Deregulation
    C. Paperwork Reduction Act (PRA)
    D. Regulatory Flexibility Act (RFA)
    E. Unfunded Mandates Reform Act (UMRA)
    F. Executive Order 13132: Federalism
    G. Executive Order 13175: Coordination With Indian Tribal 
Governments
    H. Executive Order 13045: Protection of Children From 
Environmental Health Risks and Safety Risks
    I. Executive Order 13211: Actions That Significantly Affect 
Energy Supply, Distribution, or Use
    J. National Technology Transfer and Advancement Act (NTTAA)

I. Background

A. The 2012 Annual PM2.5 NAAQS

    Under section 109 of the CAA, the EPA has established NAAQS for 
certain pervasive air pollutants (referred to as ``criteria 
pollutants'') and conducts periodic reviews of the NAAQS to determine 
whether they should be revised or whether new NAAQS should be 
established. The EPA established these standards after considering 
substantial evidence from numerous health studies demonstrating that 
serious adverse health effects are associated with exposures to these 
criteria pollutants.\1\
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    \1\ For a given air pollutant ``primary'' NAAQS are those 
determined by the EPA as requisite to protect the public health, 
allowing an adequate margin of safety, and ``secondary'' standards 
are those determined by the EPA as requisite to protect the public 
welfare from any known or anticipated adverse effects associated 
with the presence of such air pollutant in the ambient air. See CAA 
section 109(b).
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    Particulate matter includes particles with diameters that are 
generally 2.5 microns or smaller (PM2.5), and particles with 
diameters that are generally 10 microns or smaller (PM10). 
PM2.5 can be emitted by sources directly into the atmosphere 
as a solid or liquid particle (``primary PM2.5'' or ``direct 
PM2.5'') or can be formed in the atmosphere (``secondary 
PM2.5'') as a result of various chemical reactions among 
precursor pollutants such as nitrogen oxides, sulfur dioxide, volatile 
organic compounds, and ammonia.\2\
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    \2\ 80 FR 15340, 15342 (March 23, 2015).
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    Epidemiological studies have shown statistically significant 
correlations between elevated PM2.5 levels and detrimental 
effects to human health and the environment. The health effects 
associated with PM2.5 exposure include changes in lung 
function resulting in the development of respiratory symptoms, 
aggravation of existing respiratory conditions, and cardiovascular 
disease (as indicated by increased hospital admissions, emergency room 
visits, absences from school or work, and restricted activity days), 
and premature mortality. Individuals particularly sensitive to 
PM2.5 exposure include older adults, people with heart and 
lung disease, and children.\3\ Elevated PM2.5 levels also 
have adverse secondary effects such as visibility impairment and damage 
to vegetation and ecosystems.
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    \3\ EPA, Air Quality Criteria for Particulate Matter, No. EPA/
600/P-99/002aF and EPA/600/P-99/002bF, October 2004.
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    On July 18, 1997, the EPA first established annual and 24-hour 
NAAQS for PM2.5.\4\ The annual primary and secondary 
standards were set at 15.0 micrograms per cubic meter ([micro]g/m\3\) 
based on a 3-year average of annual mean PM2.5 
concentrations. Then, on January 15, 2013, the EPA promulgated a more 
stringent annual PM2.5 NAAQS, revising the primary standard 
to 12.0 [micro]g/m\3\ based on a 3-year average of annual mean 
PM2.5 concentrations, while retaining the secondary standard 
at 15.0 [micro]g/m\3\.\5\
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    \4\ 62 FR 38652 (July 18, 1997). In October 2006, the EPA 
lowered the 24-hour NAAQS for PM2.5 from 65 micrograms 
per cubic meter ([micro]g/m\3\) to 35 [micro]g/m\3\. 71 FR 61144 
(October 17, 2006).
    \5\ 78 FR 3086 (January 15, 2013) and 40 CFR 50.18. Unless 
otherwise noted, all references to the PM2.5 NAAQS in 
this document are to the 2012 annual NAAQS of 12.0 [micro]g/m\3\, 
codified at 40 CFR 50.18.
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B. CAA Requirements for PM2.5 Nonattainment Areas

    The CAA requires states to develop state implementation plan (SIP) 
revisions that provide generally for the attainment, maintenance, and 
enforcement of the NAAQS. In addition, the CAA requires states to make 
a specific type of SIP submittal, a nonattainment plan submittal, that 
imposes additional controls for purposes of attaining the 
PM2.5 NAAQS, to achieve reductions of PM2.5 and 
PM2.5 precursor emissions.
    The general CAA part D nonattainment area planning requirements are 
found in subpart 1 and the nonattainment area planning requirements 
specific to particulate matter are found in subpart 4. The subpart 1 
statutory requirements for attainment plans include the following: the 
section 172(c)(1) requirements for reasonably available control 
measures, including reasonably available control technology (RACM/
RACT), and attainment demonstrations; the section 172(c)(2) requirement 
to demonstrate reasonable further progress (RFP); the section 172(c)(3) 
requirement for emissions inventories; the section 172(c)(5) 
requirements for a nonattainment new source review (NNSR) permitting 
program; and the section 172(c)(9) requirement for contingency 
measures.
    The more specific subpart 4 statutory requirements for Moderate 
PM2.5

[[Page 27226]]

nonattainment areas include the following: the section 189(a)(1)(A) 
NNSR permit program requirements; the section 189(a)(1)(B) requirements 
for attainment demonstrations; the section 189(a)(1)(C) requirements 
for RACM/RACT; the section 189(c) requirements for RFP and quantitative 
milestones; and the section 189(e) requirement for controls on sources 
of particulate matter precursors.
    Under subpart 4, states with Moderate PM2.5 
nonattainment areas must provide for attainment in the area as 
expeditiously as practicable but no later than the end of the sixth 
calendar year after designation. For the 2012 PM2.5 annual 
NAAQS, this date was December 31, 2021. In addition, under subpart 4, 
direct PM2.5 and all precursors to the formation of 
PM2.5 are subject to control unless the EPA approves a 
demonstration from the state establishing that a given precursor does 
not contribute significantly to PM2.5 levels that exceed the 
PM2.5 NAAQS in the area.\6\
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    \6\ 40 CFR 51.1006 and 51.1009.
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    To implement the PM2.5 NAAQS, the EPA has also 
promulgated the ``Fine Particle Matter National Ambient Air Quality 
Standard: State Implementation Plan Requirements; Final Rule'' 
(``PM2.5 Implementation Rule'').\7\ The PM2.5 
Implementation Rule provides additional regulatory requirements and 
guidance applicable to attainment plan submittals for the 
PM2.5 NAAQS, including the 2012 annual PM2.5 
NAAQS at issue in this action.
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    \7\ 81 FR 58010 (August 24, 2016).
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C. Portola Nonattainment Area Designation for the 2012 PM2.5 NAAQS and 
SIP Actions

    Following promulgation of new or revised NAAQS, the EPA is required 
under CAA section 107(d) to designate regions throughout the nation as 
attaining or not attaining these NAAQS. Those regions found not to be 
attaining the NAAQS are also given a classification that reflects the 
degree of nonattainment. Under subpart 4 of part D of title I of the 
CAA, the EPA designates areas found to be violating the 
PM2.5 NAAQS, and areas that contribute to such violations, 
as nonattainment and classifies them initially as Moderate 
nonattainment areas.
    Effective January 15, 2015, the EPA designated the Portola 
nonattainment area \8\ for the 2012 PM2.5 NAAQS based on 
ambient monitoring data that showed the area was above the 12.0 
[micro]g/m\3\ primary standard for the three-year 2011-2013 monitoring 
period.\9\ For this 2011-2013 monitoring period, the annual 
PM2.5 design value \10\ for the Portola nonattainment area 
was 12.8 [micro]g/m\3\ at the Portola PM2.5 monitoring 
site.\11\
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    \8\ The boundaries of the nonattainment area are list in 40 CFR 
81.305.
    \9\ 80 FR 2206 (January 15, 2015).
    \10\ A design value is the three-year average NAAQS metric that 
is compared to the NAAQS level to determine when a monitoring site 
meets or does not meet the NAAQS. The specific methodologies for 
calculating whether the annual PM2.5 NAAQS is met at each 
eligible monitoring site in an area are found in 40 CFR part 50, 
appendix N, section 4.1.
    \11\ From 2000 through early 2013, the Portola PM2.5 
monitoring site was located at 161 Nevada Street. In 2013, the site 
was relocated to 420 Gulling Street where it remains to date.
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    This Moderate nonattainment designation and classification required 
the state of California to submit an attainment plan for the Portola 
nonattainment area, in accordance with the requirements of CAA sections 
172(c) and 189(a), (c), and (e), demonstrating attainment of the NAAQS 
as expeditiously as practical but no later than the end of the sixth 
calendar year following the designation, or December 31, 2021.
    Under state law, the local air district with the primary 
responsibility for developing a plan to attain the 2012 annual 
PM2.5 NAAQS in this area is the Northern Sierra Air Quality 
Management District (NSAQMD or ``District''). The District worked with 
the California Air Resources Board (CARB) in preparing the plan. On 
February 28, 2017, California submitted the ``Portola Fine Particulate 
Matter (PM2.5) Attainment Plan'' (``Portola PM2.5 
Plan'') to address the CAA's Moderate nonattainment area requirements 
for the 2012 annual PM2.5 NAAQS. On March 25, 2019, the EPA 
fully approved the Portola PM2.5 Plan, except for the 
contingency measure elements.\12\ California later submitted a revision 
to the Portola PM2.5 Plan (``PM2.5 Plan 
Revision''), which included a contingency measure adopted in an 
ordinance by the City of Portola.
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    \12\ 84 FR 11208 (March 25, 2019).
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    On April 2, 2021, the EPA took final action to approve the 
PM2.5 Plan Revision.\13\ We also found that the contingency 
measure element of the Portola PM2.5 Plan, as revised and 
supplemented by the PM2.5 Plan Revision, satisfied the 
requirements for contingency measures in CAA section 172(c)(9) and 40 
CFR 51.1014 for purposes of the 2012 PM2.5 NAAQS in the 
Portola nonattainment area.\14\
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    \13\ 86 FR 12263 (March 3, 2021).
    \14\ Id.
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    On December 29, 2022, the EPA determined that the Portola 
nonattainment area did not attain the 2012 annual PM2.5 
NAAQS by its applicable Moderate area attainment date of December 31, 
2021.\15\ Pursuant to CAA section 188(b)(2), the Portola nonattainment 
area was reclassified as a Serious PM2.5 nonattainment area 
effective January 30, 2023.
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    \15\ 87 FR 80076.
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    On December 24, 2024, CARB submitted the ``Portola Fine Particulate 
Matter (PM2.5) Serious State Implementation Plan'' to 
address the Serious area requirements for the Portola nonattainment 
area.

D. CAA Requirement for a Determination of Attainment

    Sections 179(c) and 188(b)(2) of the CAA require that within six 
months following the applicable attainment date, the EPA shall 
determine whether a nonattainment area attained the standard by that 
date. The Serious attainment date for the 2012 PM2.5 NAAQS 
in the Portola nonattainment area was December 31, 2025. Therefore, the 
determination of whether the area attained by the Serious attainment 
date is based on the 2023-2025 design value. Section 179(c)(2) of the 
CAA requires the EPA to publish the determination in the Federal 
Register no later than 6 months after the attainment date, that is, in 
the case of the Portola nonattainment area, by June 30, 2026.

E. The EPA's Clean Data Policy

    Under the EPA's longstanding Clean Data Policy, which was codified 
in the PM2.5 Implementation Rule at 40 CFR 51.1015, when an 
area has attained the relevant PM2.5 standard(s), the EPA 
may issue a CDD (also sometimes referred to as a determination of 
attainment for the purposes of the Clean Data Policy) after notice and 
comment rulemaking determining that a specific area is attaining the 
relevant standard(s). A CDD is not linked to any particular attainment 
deadline and is not necessarily equivalent to a determination that an 
area has attained the standard by its applicable attainment deadline 
(i.e., a DAAD).
    The effect of a CDD for a Serious PM2.5 nonattainment 
area is to suspend the requirements for the area to submit an 
attainment demonstration, RFP plan, quantitative milestones and 
quantitative milestone reports, and contingency measures for as long as 
the area continues to attain the standard.\16\ A

[[Page 27227]]

CDD does not suspend the requirements for an emissions inventory, for 
new source review, or for BACM/BACT in a Serious PM2.5 
nonattainment area.
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    \16\ 40 CFR 51.1015. In the context of CDDs, the EPA 
distinguishes between attainment planning requirements of the CAA, 
which relate to the attainment demonstration for an area and related 
control measures designed to bring an area into attainment for the 
given NAAQS as expeditiously as practicable, and other types of 
requirements, such as permitting requirements under the 
nonattainment new source review program, emissions inventory 
requirement, and specific control requirements independent of those 
strictly needed to ensure timely attainment of the given NAAQS. 81 
FR 58010, 58128.
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II. Proposed Determination of Attainment

A. Applicable Statutory and Regulatory Provisions

    Sections 179(c)(1) of the CAA requires the EPA to determine whether 
a nonattainment area attained by the applicable attainment date, based 
on the area's air quality ``as of the attainment date.'' \17\ 
Generally, this determination of whether an area's air quality meets 
the PM2.5 standard(s) is based upon the most recent three 
years of complete, certified data gathered at eligible monitoring sites 
in accordance with 40 CFR part 58.\18\ The requirements of 40 CFR part 
58 include quality assurance procedures for monitor operation and data 
handling, siting parameters for instruments or instrument probes, and 
minimum ambient air quality monitoring network requirements. State, 
local, or Tribal agencies operating air monitoring sites, in accordance 
with 40 CFR part 58, must enter the ambient air quality data and 
associated quality assurance data from these sites into the EPA's Air 
Quality System (AQS) database.\19\ These monitoring agencies certify 
annually that these data are accurate to the best of their knowledge, 
taking into consideration the quality assurance findings.\20\ 
Accordingly, the EPA relies primarily on AQS data when determining the 
attainment status of an area. In determining whether data are suitable 
for regulatory determinations, the EPA uses a ``weight of evidence'' 
approach, considering the requirements of 40 CFR part 58, appendix A 
``in combination with other data quality information, reports, and 
similar documentation that demonstrate overall compliance with 40 CFR 
part 58.'' \21\
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    \17\ See also CAA section 188(b)(2) (``Within 6 months following 
the applicable attainment date for a PM-10 nonattainment area, the 
Administrator shall determine whether the area attained the standard 
by that date.'')
    \18\ 40 CFR part 50, appendix N, section 3.0.
    \19\ 40 CFR 58.16. AQS is the EPA's national repository of 
ambient air quality data.
    \20\ 40 CFR 58.15(a).
    \21\ 40 CFR part 58, appendix A, section 1.2.3.
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    The 2012 primary annual PM2.5 standard is met when the 
three year average of the annual arithmetic mean concentration, as 
determined in accordance with 40 CFR part 50, appendix N, is less than 
or equal to 12.0 [micro]g/m\3\ at each eligible monitoring site.\22\ 
For the annual PM2.5 standard, eligible monitoring sites are 
those monitoring stations that meet the criteria specified in 40 CFR 
58.11 and 58.30, and thus are approved for comparison to the annual 
PM2.5 NAAQS.\23\ Three years of valid annual means are 
required to produce a valid annual PM2.5 NAAQS design 
value.\24\ Data completeness requirements for a given year are met when 
at least 75 percent of the scheduled sampling days for each quarter 
have valid data.\25\
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    \22\ 40 CFR 50.18(b); 40 CFR part 50, appendix N, section 
4.1(a).
    \23\ 40 CFR part 50, appendix N, section 1.0(c).
    \24\ 40 CFR part 50, appendix N, section 4.1(b).
    \25\ Id.
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B. Monitoring Network Review, Quality Assurance, and Data Completeness

    The Portola monitoring site (AQS ID: 06-063-1010) is the only 
regulatory PM2.5 monitoring site in the Portola 
nonattainment area and is operated by the District. CARB serves as the 
primary quality assurance organization (PQAO) and submits annual 
monitoring network plans to the EPA documenting the status of CARB's 
air monitoring network, including monitors operated by NSAQMD and other 
local air districts, as required under 40 CFR 58.10.\26\ The EPA 
reviews these annual network plans for compliance with specific 
requirements in 40 CFR part 58. With respect to the Portola 
nonattainment area, we have found that the annual network plans 
submitted by CARB meet these requirements under 40 CFR part 58, 
including minimum monitoring requirements.\27\
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    \26\ We have included copies of CARB's annual monitoring network 
plans for 2023-2025 in our docket.
    \27\ We have included our reviews of CARB's annual monitoring 
network plans and the correspondence transmitting these reviews in 
our docket.
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    In accordance with 40 CFR 58.15, the District certifies annually 
that the previous year's ambient concentration and quality assurance 
data are completely submitted to AQS and that the ambient concentration 
data are accurate to the best of their knowledge, taking into 
consideration the quality assurance findings.\28\ Along with the 
certification letters, the District submits a summary of the precision 
and accuracy data for all ambient air quality data.\29\
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    \28\ We have included NSAQMD's annual data certifications for 
2023, 2024, and 2025 in the docket for this action. We have also 
included our reviews of NSAQMD's annual data certifications and the 
correspondence transmitting these reviews in the docket.
    \29\ See 40 CFR 58.15(c).
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    The Design Value Report also includes a validity indicator that 
reflects whether the design value is valid (i.e., calculated using data 
that meet the applicable completeness criteria). For the purposes of 
this proposal, we reviewed the certified ambient data for the 2023-2025 
monitoring period for completeness and determined that the 
PM2.5 data collected by the District met the 75 percent 
completeness criterion for all 12 quarters at the Portola monitoring 
site.
    Finally, the EPA conducts regular technical systems audits (TSAs) 
of state and local ambient air monitoring programs to assess compliance 
with applicable regulations concerning the collection, analysis, 
validation, and reporting of ambient air quality data. Additionally, 
CARB conducts regular TSAs of local ambient air monitoring programs 
within their PQAO. For the purposes of this proposal, we reviewed the 
findings from the EPA's 2022 TSA of CARB's ambient air monitoring 
program.\30\ None of the findings from the 2022 TSA were cause for 
invalidation of any data from the Portola PM2.5 monitoring 
site.\31\ We also reviewed the findings of CARB's TSA of the District 
in May 2024.\32\ The results of the TSA do not preclude the EPA from 
using the data for determining whether the Portola nonattainment area 
has attained the 2012 annual PM2.5 NAAQS.
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    \30\ Letter dated March 14, 2024, from Matthew Lakin, Director, 
Air and Radiation Division, EPA Region IX, to Edie Chang, Executive 
Officer, CARB, with enclosure titled ``Technical Systems Audit of 
the Ambient Air Monitoring Program: California Air Resources Board 
December 2021-August 2022'' (Final Report dated March 2024).
    \31\ Id.
    \32\ Letter dated April 21, 2026, from Manisha Singh, Chief, 
Quality Management Branch, CARB, to Julie Hunter, Air Pollution 
Control Officer, Northern Sierra Air Quality Management District, 
with enclosure titled ``Technical Systems Audit of Northern Sierra 
Air Quality Management District'' (April 2026).
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    In summary, based on the relevant annual monitoring network plans, 
certifications, and 2022 TSA, we propose to find that the 
PM2.5 data collected at the Portola monitoring site are 
suitable for determining whether the Portola nonattainment area 
attained the 2012 annual PM2.5 NAAQS by the applicable 
attainment date.

C. The EPA's Evaluation of Attainment

    Table 1 provides the PM2.5 design value from the 
regulatory monitor within the Portola nonattainment area, expressed as 
a single design value representing the average of the annual

[[Page 27228]]

mean values from the 2023-2025 period; the annual mean for each 
individual year is also listed. The PM2.5 data show that the 
design value at the Portola monitoring site was 11.3 [micro]g/m\3\, 
which meets the 2012 annual PM2.5 NAAQS of 12.0 [micro]g/
m\3\. Consequently, the EPA proposes to determine based upon three 
years of complete, quality-assured and certified data from 2023 through 
2025, that the Portola nonattainment area attained the 2012 annual 
PM2.5 NAAQS by the applicable Serious attainment date of 
December 31, 2025.

                                     Table 1--2023-2025 Annual PM2.5 Design Value for the Portola Nonattainment Area
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                                                                                             Annual weighted mean ([micro]g/m\3\)           2023-2025
                                                                                     ---------------------------------------------------  annual design
                          Monitoring site                             AQS site ID #                                                      value ([micro]g/
                                                                                            2023             2024             2025            m\3\)
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Portola............................................................     06-063-1010             11.9             11.3             10.7             11.3
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Source: EPA AQS Design Value Report, AMP480, dated March 31, 2026. (Report Request ID: 2367374).

III. Proposed Clean Data Determination

    As described in section I.E of this document, when an area has 
attained the relevant PM2.5 standard(s), the EPA may issue a 
CDD after notice and comment rulemaking determining that a specific 
area is attaining the relevant standard.\33\ As described in section 
II.C, based on complete, quality-assured, and certified data for 2023-
2025, the Portola nonattainment area meets the 2012 annual 
PM2.5 standard. Consequently, the EPA is proposing to issue 
a CDD under 40 CFR 51.1015(b).
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    \33\ 40 CFR 51.1015.
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    If we finalize this proposed CDD, the requirements for the State to 
submit an attainment demonstration, an RFP plan, quantitative 
milestones and quantitative milestone reports, and contingency measures 
for the area will be suspended until such time as: (1) the area is 
redesignated to attainment, after which such requirements are 
permanently discharged; or, (2) the EPA determines that the area has 
re-violated the 2012 PM2.5 NAAQS, after which time the state 
shall submit such attainment plan elements for the Serious 
nonattainment area by a future date to be determined by the EPA and 
announced through publication in the Federal Register at the time the 
EPA determines the area is violating the 2012 PM2.5 
NAAQS.\34\ The requirements to submit emissions inventories and an NNSR 
permitting program for the Serious nonattainment area will remain in 
effect.
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    \34\ 40 CFR 51.1015(b).
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IV. The EPA's Proposed Action

    For the reasons discussed in this document, the EPA is proposing to 
determine, based on the most recent three years (2023-2025) of 
complete, quality-assured, and certified data that the Portola 
nonattainment area attained the 2012 annual PM2.5 NAAQS by 
its December 31, 2025 attainment date. This action, when finalized, 
will fulfill the EPA's statutory obligation to determine whether the 
Portola nonattainment area attained the NAAQS by the attainment date.
    We are also proposing a CDD under 40 CFR 51.1015(b). If the EPA 
finalizes this proposal, the requirements for this area to submit an 
attainment demonstration, RFP plan, quantitative milestones and 
quantitative milestone reports, and contingency measures, for the 2012 
annual PM2.5 NAAQS, will be suspended so long as this area 
continues to meet the standard. This CDD does not constitute a 
redesignation to attainment. The Portola nonattainment area will remain 
designated nonattainment for the 2012 annual PM2.5 NAAQS 
until such time as the EPA determines, pursuant to sections 107 and 
175A of the CAA, that the Portola nonattainment area meets the CAA 
requirements for redesignation to attainment, including an approved 
maintenance plan showing that the area will continue to meet the 
standard for 10 years.

V. Statutory and Executive Order Reviews

    Additional information about these statutes and Executive Orders 
can be found at https://www.epa.gov/laws-regulations/laws-and-executive-orders.

A. Executive Order 12866: Regulatory Planning and Review and Executive 
Order 13563: Improving Regulation and Regulatory Review

    This action is not a significant regulatory action and was 
therefore not submitted to the Office of Management and Budget (OMB) 
for review. This action proposes to issue a DAAD and CDD for the 
Portola nonattainment area.

B. Executive Order 14192: Unleashing Prosperity Through Deregulation

    This action is not expected to be an Executive Order 14192 
regulatory action because this action is not significant under 
Executive Order 12866.

C. Paperwork Reduction Act (PRA)

    This action does not impose an information collection burden under 
the PRA. This action proposes to determine that the Portola 
nonattainment area is attaining the 2012 PM2.5 NAAQS. Thus, 
this proposed action does not impose additional requirements beyond 
those imposed by state law.

D. Regulatory Flexibility Act (RFA)

    I certify that this action will not have a significant economic 
impact on a substantial number of small entities under the RFA. This 
action will not impose any requirements on small entities beyond those 
imposed by state law. The proposed DAAD and CDD do not create any new 
requirements and does not directly regulate any entities.

E. Unfunded Mandates Reform Act (UMRA)

    This action does not contain any unfunded mandate as described in 
UMRA, 2 U.S.C. 1531-1538, and does not significantly or uniquely affect 
small governments. This action does not impose additional requirements 
beyond those imposed by state law. Accordingly, no additional costs to 
state, local, or Tribal governments, or to the private sector, will 
result from this action.

F. Executive Order 13132: Federalism

    This action does not have federalism implications. It will not have 
substantial direct effects on the states, on the relationship between 
the national government and the states, or on the distribution of power 
and responsibilities among the various levels of government. Pursuant 
to the CAA, this action proposes a DAAD and CDD.

G. Executive Order 13175: Coordination With Indian Tribal Governments

    This action does not have Tribal implications as specified in 
Executive Order 13175. As there are no federally recognized Tribes 
within the Portola

[[Page 27229]]

nonattainment area,\35\ the proposed DAAD and CDD not apply to Tribal 
areas, and the proposed rule would not impose a burden on Indian 
reservation lands or other areas where the EPA or an Indian Tribe has 
demonstrated that a Tribe has jurisdiction within the Portola 
nonattainment area. Thus, this proposed rule does not have Tribal 
implications and will not impose substantial direct costs on Tribal 
governments or preempt Tribal law as specified by Executive Order 
13175.
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    \35\ Map of Federally-Recognized Tribes in EPA's Pacific 
Southwest (Region 9) is available at https://www.epa.gov/tribal-pacific-sw/map-federally-recognized-tribes-epas-pacific-southwest-region-9.
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H. Executive Order 13045: Protection of Children From Environmental 
Health Risks and Safety Risks

    The EPA interprets Executive Order 13045 as applying only to those 
regulatory actions that concern environmental health or safety risks 
that the EPA has reason to believe may disproportionately affect 
children, per the definition of ``covered regulatory action'' in 
section 2-202 of the Executive Order. Therefore, this action is not 
subject to Executive Order 13045 because it merely proposes a DAAD and 
CDD. Furthermore, the EPA's Policy on Children's Health does not apply 
to this action.

I. Executive Order 13211: Actions That Significantly Affect Energy 
Supply, Distribution, or Use

    This action is not subject to Executive Order 13211, because it is 
not a significant regulatory action under Executive Order 12866.

J. National Technology Transfer and Advancement Act (NTTAA)

    Section 12(d) of the NTTAA directs the EPA to use voluntary 
consensus standards in its regulatory activities unless to do so would 
be inconsistent with applicable law or otherwise impractical. The EPA 
believes that this action is not subject to the requirements of section 
12(d) of the NTTAA because application of those requirements would be 
inconsistent with the CAA.

List of Subjects

40 CFR Part 52

    Environmental protection, Air pollution control, Incorporation by 
reference, Particulate matter, Reporting and recordkeeping 
requirements.

40 CFR Part 81

    Environmental protection, Administrative practice and procedure, 
Air pollution control, Designations and classifications, 
Intergovernmental relations, Particulate matter, Reporting and 
recordkeeping requirements.

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

    Dated: May 1, 2026.
Michael Martucci,
Acting Regional Administrator, Region IX.
[FR Doc. 2026-09604 Filed 5-13-26; 8:45 am]
BILLING CODE 6560-50-P