Proposed Rule2026-11736
Attainment Date Extension for the South Coast, California 2012 Annual PM2.5 Fine Particulate Matter Nonattainment Area
Primary source
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Published
June 11, 2026
Issuing agencies
Environmental Protection Agency
Abstract
The Environmental Protection Agency (EPA) is proposing to grant an extension of the "Serious" area attainment date for the Los Angeles-South Coast Air Basin ("South Coast") nonattainment area for the 2012 annual fine particulate matter (PM<INF>2.5</INF>) national ambient air quality standards (NAAQS or "standards") from December 31, 2025, to December 31, 2030, based on a proposed determination that the State has satisfied the statutory criteria for this extension. The EPA will accept comments on this proposed rule during a 30-day public comment period.
Full Text
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<title>Federal Register, Volume 91 Issue 112 (Thursday, June 11, 2026)</title>
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[Federal Register Volume 91, Number 112 (Thursday, June 11, 2026)]
[Proposed Rules]
[Pages 35445-35455]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2026-11736]
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ENVIRONMENTAL PROTECTION AGENCY
40 CFR Part 52
[EPA-R09-OAR-2026-3664; FRL-13379-01-R9]
Attainment Date Extension for the South Coast, California 2012
Annual PM2.5 Fine Particulate Matter Nonattainment Area
AGENCY: Environmental Protection Agency (EPA).
ACTION: Proposed rule.
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SUMMARY: The Environmental Protection Agency (EPA) is proposing to
grant an extension of the ``Serious'' area attainment date for the Los
Angeles-South Coast Air Basin (``South Coast'') nonattainment area for
the 2012 annual fine particulate matter (PM<INF>2.5</INF>) national
ambient air quality standards (NAAQS or ``standards'') from December
31, 2025, to December 31, 2030, based on a proposed determination that
the State has satisfied the statutory criteria for
[[Page 35446]]
this extension. The EPA will accept comments on this proposed rule
during a 30-day public comment period.
DATES: Comments must be received on or before July 13, 2026.
ADDRESSES: Submit your comments, identified by Docket ID No. EPA-R09-
OAR-2026-3664 at <a href="https://www.regulations.gov">https://www.regulations.gov</a>. For comments submitted at
<a href="http://Regulations.gov">Regulations.gov</a>, follow the online instructions for submitting
comments. Once submitted, comments cannot be edited or removed from
<a href="http://Regulations.gov">Regulations.gov</a>. 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 <a href="https://www.epa.gov/dockets/commenting-epa-dockets">https://www.epa.gov/dockets/commenting-epa-dockets</a>. 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: Ashley Graham; Geographic Strategies
and Modeling Section (AIR-2-2); EPA Region IX; 75 Hawthorne Street, San
Francisco, CA 94105; telephone number: (415) 972-3877; email address:
<a href="/cdn-cgi/l/email-protection#2146534049404c0f4052494d445853614451400f464e57"><span class="__cf_email__" data-cfemail="284f5a4940494506495b40444d515a684d5849064f475e">[email protected]</span></a>.
SUPPLEMENTARY INFORMATION: Throughout this document, ``we,'' ``us,''
and ``our'' refer to the EPA.
Table of Contents
I. Background for Proposed Action
A. PM<INF>2.5</INF> NAAQS
B. South Coast PM2.5 Designations, Classifications, and SIP
Revisions
II. Completeness Review of the 2024 South Coast PM<INF>2.5</INF>
Plan
III. Clean Air Act Requirements for an Extension of a Serious Area
Attainment Date
IV. Review of the South Coast PM<INF>2.5</INF> Extension Application
A. Demonstration That Attainment by Serious Area Attainment Date
Is Impractical
B. Compliance With All Requirements and Commitments in the
Implementation Plan
C. Demonstration That the Implementation Plan Includes the Most
Stringent Measures
D. Demonstration of Attainment by the Most Expeditious
Alternative Date Practicable
E. Application for an Attainment Date Extension
F. Other Factors That the EPA May Consider
V. Summary of Proposed Action and Request for Public Comment
VI. Statutory and Executive Order Reviews
I. Background for Proposed Action
A. PM<INF>2.5</INF> NAAQS
Under section 109 of the Clean Air Act (CAA or ``Act''), 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. On January 15, 2013, the EPA strengthened the primary
annual NAAQS for PM<INF>2.5</INF> by lowering the level from 15.0
[micro]g/m\3\ to 12.0 [micro]g/m\3\ (``2012 annual PM<INF>2.5</INF>
NAAQS'').\1\
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\1\ 78 FR 3086 (January 15, 2013) and 40 CFR 50.18. Unless
otherwise noted, all references to the PM<INF>2.5</INF> standards in
this document are to the 2012 annual PM<INF>2.5</INF> NAAQS of 12.0
[micro]g/m\3\ codified at 40 CFR 50.18.
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The EPA established the PM<INF>2.5</INF> NAAQS after considering
substantial evidence from numerous health studies demonstrating that
serious health effects are associated with exposures to
PM<INF>2.5</INF> concentrations above these levels. Epidemiological
studies have shown statistically significant correlations between
elevated PM<INF>2.5</INF> levels and premature mortality. Other
important health effects associated with PM<INF>2.5</INF> 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 dates), changes
in lung function, and increased respiratory symptoms. Individuals
particularly sensitive to PM<INF>2.5</INF> exposure include older
adults, people with heart and lung disease, and children.\2\
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\2\ EPA, Air Quality Criteria for Particulate Matter, No. EPA/
600/P-99/002aF and EPA/600/P-99/002bF, October 2004.
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Sources can emit PM<INF>2.5</INF> directly into the atmosphere as a
solid or liquid particle (primary PM<INF>2.5</INF> or direct
PM<INF>2.5</INF>), or PM<INF>2.5</INF> can form in the atmosphere
(secondary PM<INF>2.5</INF>) as a result of various chemical reactions
from precursor emissions of nitrogen oxides (NO<INF>X</INF>), sulfur
oxides (SO<INF>X</INF>), volatile organic compounds (VOC), and
ammonia.\3\
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\3\ 81 FR 58010, 58011 (August 24, 2016).
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B. South Coast PM2.5 Designations, Classifications, and SIP Revisions
The South Coast PM<INF>2.5</INF> nonattainment area is home to
approximately 17 million people, has a diverse economic base, and
contains one of the highest volume port areas in the world. For a
precise description of the geographic boundaries of the South Coast
PM<INF>2.5</INF> nonattainment area, see 40 CFR 81.305. The local air
district with primary responsibility for developing a plan to attain
the 2012 annual PM<INF>2.5</INF> NAAQS in the South Coast nonattainment
area is the South Coast Air Quality Management District (SCAQMD or
``District''). The District works cooperatively with the California Air
Resources Board (CARB) in preparing these plans. Authority for
regulating sources in the South Coast nonattainment area is split
between the District, which has responsibility for regulating
stationary and most area sources, and CARB, which has responsibility
for regulating most mobile sources and some categories of consumer
products.
Following promulgation of a new or revised NAAQS, the EPA is
required under CAA section 107(d) to designate areas throughout the
nation as attaining or not attaining the NAAQS. On January 15, 2015,
the EPA designated and classified the South Coast area as ``Moderate''
nonattainment for the 2012 annual PM<INF>2.5</INF> NAAQS, effective
April 15, 2015.\4\
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\4\ 80 FR 2206 (January 15, 2015) (codified at 40 CFR 81.305).
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On April 27, 2017, CARB submitted the ``Final 2016 Air Quality
Management Plan (March 2017)'' (``2016 PM<INF>2.5</INF> Plan'') to
address the CAA requirements associated with the 2012 annual
PM<INF>2.5</INF> NAAQS in the South Coast.\5\ The 2016 PM<INF>2.5</INF>
Plan included a demonstration, to address the requirements of CAA
section 189(a)(1)(B), that attainment of the 2012 annual
PM<INF>2.5</INF> NAAQS by the December 31, 2021 Moderate area
attainment date in the South Coast area was impracticable, despite the
implementation of required control measures.\6\ The 2016
PM<INF>2.5</INF> Plan also included a request that the EPA
[[Page 35447]]
reclassify the nonattainment area from Moderate nonattainment to
Serious nonattainment, and included a Serious area attainment
demonstration, emissions inventories, attainment related plan elements,
and control measure provisions.\7\ Effective December 9, 2020, the EPA
approved or conditionally approved the portions of the 2016
PM<INF>2.5</INF> Plan that pertain to the Moderate area planning
requirements for the 2012 annual PM<INF>2.5</INF> NAAQS in the South
Coast nonattainment area and, pursuant to CAA section 188(b)(1),
reclassified the area as a Serious nonattainment area.\8\
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\5\ Letter dated April 27, 2017, from Richard Corey, Executive
Officer, CARB, to Alexis Strauss, Acting Regional Administrator, EPA
Region IX (transmitting the ``Final 2016 Air Quality Management Plan
(March 2017)'') (submitted electronically April 27, 2017).
\6\ 85 FR 71264, 71266 (November 9, 2020).
\7\ Id. at 71268.
\8\ Id. at 71264.
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Upon reclassification as a Serious PM<INF>2.5</INF> nonattainment
area, the South Coast area became subject to a new statutory attainment
date of as expeditiously as practicable but no later than the end of
the tenth calendar year following designation (i.e., December 31, 2025)
and a requirement to submit a Serious area plan satisfying the
requirements of CAA title I, part D, including the requirements of
subpart 4, for the 2012 annual PM<INF>2.5</INF> NAAQS.\9\ As explained
in the EPA's final reclassification action, the Serious area plan for
the South Coast must include, among other things, provisions to assure
that, under CAA section 189(b)(1)(B), the best available control
measures (BACM) for the control of direct PM<INF>2.5</INF> and
PM<INF>2.5</INF> precursors shall be implemented no later than four
years after the area is reclassified and a demonstration (including air
quality modeling) that the plan provides for attainment as
expeditiously as practicable and no later than the applicable
attainment date. The EPA also noted that California may choose to
submit a request for an extension of the December 31, 2025, Serious
area attainment date pursuant to CAA section 188(e).\10\
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\9\ Id. at 71266 through 71268.
\10\ Id. at 71267.
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Our final action on the 2016 PM<INF>2.5</INF> Plan's Moderate area
requirements and reclassification of the nonattainment area to Serious
noted that the submitted 2016 PM<INF>2.5</INF> Plan included Serious
area planning elements for the 2012 annual PM<INF>2.5</INF> NAAQS and
stated that we would evaluate and act on those elements through
subsequent rulemakings as appropriate.\11\ On March 29, 2023, the CARB
and the District notified the EPA of their determination that the
portions of the 2016 PM<INF>2.5</INF> Plan pertaining to the Serious
area planning requirements for the 2012 annual PM<INF>2.5</INF> NAAQS
were no longer appropriate for inclusion in the SIP and requested that
those portions of the submittal be considered withdrawn.\12\
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\11\ Id. at 71268.
\12\ Letter dated March 8, 2023, from Sarah Rees, Deputy
Executive Officer, Planning, Rule Development & Implementation,
SCAQMD, to Michael Benjamin, Chief, Air Quality Planning and Science
Division, CARB (submitted electronically March 29, 2023); and letter
dated March 29, 2023, from Michael Benjamin, Chief, Air Quality
Planning and Science Division, CARB to Martha Guzman, Regional
Administrator, EPA Region IX (submitted electronically March 29,
2023).
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Following the State's withdrawal of the portions of the 2016
PM<INF>2.5</INF> Plan that pertained to the Serious area planning
requirements for the 2012 annual PM<INF>2.5</INF> NAAQS, the EPA issued
two findings that California had failed to submit SIP submissions to
address the Serious area planning requirements for the 2012 annual
PM<INF>2.5</INF> NAAQS. In the first finding, published in the Federal
Register on May 26, 2023, the EPA found that California had failed to
submit revisions to address the base year emissions inventory and BACM
requirements, which the State was required to submit by June 9,
2022.\13\ In the second finding, published on January 30, 2024, the EPA
found that California had failed to submit the Serious area plan
requirements for a reasonable further progress (RFP) demonstration,
quantitative milestones, an attainment demonstration, and contingency
measures by December 31, 2023.\14\ These findings, which became
effective on June 26, 2023, and February 29, 2024, respectively,
triggered clocks under CAA section 179(a) for the application of
emissions offset sanctions 18 months after the findings, and highway
funding sanctions 6 months thereafter, unless the EPA affirmatively
determined that the State made a complete SIP submission addressing the
identified failure to submit deficiencies.\15\ The findings also
triggered the obligation under CAA section 110(c) for the EPA to
promulgate a Federal implementation plan no later than two years after
the finding, unless the State has submitted, and the EPA has approved,
the required SIP submission.\16\
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\13\ 88 FR 34093 (May 26, 2023).
\14\ 89 FR 5770 (January 30, 2024).
\15\ 88 FR 34093, 34095 (May 26, 2023) and 89 FR 5770, 5772
(January 30, 2024).
\16\ Id.
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On August 6, 2024, CARB submitted the ``South Coast Air Basin
Attainment Plan for the 2012 Annual PM<INF>2.5</INF> Standard'' (``2024
South Coast PM<INF>2.5</INF> Plan'' or ``Plan''), adopted by SCAQMD on
June 7, 2024, and by CARB on June 27, 2024, to the EPA as a revision to
the California SIP.\17\ The 2024 South Coast PM<INF>2.5</INF> Plan
addresses the Serious area nonattainment plan requirements for the 2012
annual PM<INF>2.5</INF> NAAQS in the South Coast nonattainment area and
includes a request under CAA section 188(e) for an extension of the
Serious area attainment date for the area for these NAAQS from December
31, 2025, to December 31, 2030.
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\17\ Letter dated August 5, 2024, from Steven S. Cliff,
Executive Officer, CARB, to Martha Guzman, Regional Administrator,
EPA Region IX, with enclosures (submitted electronically on August
6, 2024).
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II. Completeness Review of the 2024 South Coast PM2.5 Plan
CAA sections 110(a)(1) and (2) and 110(l) require each state to
provide reasonable public notice and opportunity for public hearing
prior to the adoption and submission of a SIP or SIP revision to the
EPA. To meet this requirement, every SIP submission should include
evidence that the state provided adequate public notice and an
opportunity for a public hearing consistent with the EPA's implementing
regulations in 40 CFR 51.102.
CAA section 110(k)(1)(B) requires the EPA to determine whether a
SIP submission is complete within 60 days of receipt. This section also
provides that any plan that the EPA has not affirmatively determined to
be complete or incomplete will become complete by operation of law six
months after the date of submission. The EPA's SIP completeness
criteria are found in 40 CFR part 51, appendix V.
On December 17, 2024, the EPA issued a letter finding that the
emissions inventory and BACM elements of the 2024 South Coast
PM<INF>2.5</INF> Plan conform to the EPA's completeness criteria in 40
CFR part 51, appendix V.\18\ On June 9, 2025, the EPA issued a second
letter finding that the RFP demonstration, quantitative milestones,
attainment demonstration, and contingency measures elements of the Plan
also conform to the completeness criteria in 40 CFR part 51, appendix
V.\19\ These completeness findings corrected the deficiencies
identified in the EPA's previous findings of failure to submit, and
terminated the sanctions clocks started by the findings.
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\18\ Letter dated December 17, 2024, from Mathew Lakin,
Director, Air and Radiation Division, EPA Region IX, to Steven S.
Cliff, Executive Officer, CARB.
\19\ Letter dated June 9, 2025, from Matthew Lakin, Director,
Air and Radiation Division, EPA Region IX, to Steven S. Cliff,
Executive Officer, CARB.
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[[Page 35448]]
III. Clean Air Act Requirements for an Extension of a Serious Area
Attainment Date
Under section 188(e) of the Act, a state may apply to the EPA for a
single extension of the Serious area attainment date by up to five
years, which the EPA may grant if the state satisfies certain
conditions. Before the EPA may extend the attainment date for a Serious
area under CAA section 188(e), the state must:
(1) Demonstrate that attainment by the Serious area attainment date
is impracticable;
(2) Demonstrate that it has complied with all requirements and
commitments pertaining to the area in the implementation plan;
(3) Demonstrate to the satisfaction of the Administrator that the
plan for the area includes the ``most stringent measures'' (MSM) that
are included in the implementation plan of any State or are achieved in
practice in any State, and can feasibly be implemented in the area;
(4) Submit a modeled attainment demonstration showing attainment of
the NAAQS in the area by the most expeditious alternative date
practicable; and
(5) Apply for an extension of the attainment date beyond the
Serious area attainment date.\20\
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\20\ CAA section 188(e) and 40 CFR 51.1005(b). For a discussion
of the EPA's interpretation of the requirements of CAA section
188(e), see 81 FR 58010, 58094 through 58097 (August 24, 2016), and
59 FR 41998, 42002 (August 16, 1994).
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A state must seek an extension of the Serious area attainment date
at the same time it submits the Serious area attainment plan if the
state cannot demonstrate attainment by the otherwise applicable
statutory attainment date.\21\
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\21\ 40 CFR 51.1005(b)(2).
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The EPA established regulatory requirements and provided further
interpretive guidance on the statutory SIP requirements that apply to
areas designated nonattainment for the PM<INF>2.5</INF> standards in an
August 24, 2016 final rule titled ``Fine Particulate Matter National
Ambient Air Quality Standards: State Implementation Plan Requirements''
(``PM<INF>2.5</INF> SIP Requirements Rule'').\22\ Under the EPA's
regulations at 40 CFR 51.1005(b)(2), a state seeking an extension of
the Serious area attainment date under CAA section 188(e) must also
submit a Serious area attainment plan that meets the following
requirements:
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\22\ 81 FR 58010 (August 24, 2016).
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(1) Base year and attainment projected emissions inventory
requirements in 40 CFR 51.1008(b);
(2) The MSM requirement in 40 CFR 51.1005(b)(1)(iii) and
51.1010(b), and best available control measures not previously
submitted;
(3) Attainment demonstration and modeling requirements in 40 CFR
51.1005(b)(1)(i) and 51.1011;
(4) RFP requirements in 40 CFR 51.1012;
(5) Quantitative milestone requirements in 40 CFR 51.1013;
(6) Contingency measure requirements in 40 CFR 51.1014; and
(7) Nonattainment new source review plan requirements pursuant to
40 CFR 51.165.\23\
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\23\ 40 CFR 51.1005(b)(2).
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In addition to establishing specific preconditions for an extension
of the Serious area attainment date, CAA section 188(e) provides that
the EPA may consider a number of factors in determining whether to
grant an extension and the appropriate length of time for any such
extension. These factors are: (1) the nature and extent of
nonattainment in the area, (2) the types and numbers of sources or
other emitting activities in the area (including the influence of
uncontrollable natural sources and trans-boundary emissions from
foreign countries), (3) the population exposed to concentrations in
excess of the standard in the area, (4) the presence and concentrations
of potentially toxic substances in the mix of particulate emissions in
the area, and (5) the technological and economic feasibility of various
control measures.\24\ Notably, neither the statutory requirements nor
the discretionary factors identified in CAA section 188(e) include the
specific ambient air quality conditions in CAA section 188(d)(2), which
must be met for an area to qualify for an extension of a Moderate area
attainment date.
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\24\ CAA section 188(e).
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The EPA is evaluating the State's request for an extension of the
Serious area attainment date in accordance with these statutory
criteria and regulatory requirements, as further described below.
1. Demonstrate That Attainment by the Serious Area Attainment Date Is
Impracticable
Section 188(e) of the Act authorizes the EPA to grant a state
request for an extension of the Serious area attainment date if, among
other things, attainment by the date established under CAA section
188(c) would be impracticable. In order to demonstrate
impracticability, EPA guidance has stated that the plan must show that
the implementation of best available control measures (BACM) and best
available control technology (BACT) (and additional feasible measures)
on relevant source categories will not bring the area into attainment
by the statutory Serious area attainment date.\25\ For the South Coast,
the Serious area attainment date for the 2012 annual PM<INF>2.5</INF>
NAAQS under CAA section 188(c)(2) is December 31, 2025.\26\
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\25\ 81 FR 58010, 58094 (August 24, 2016).
\26\ Under CAA section 188(c)(2), the attainment date for a
Serious area ``shall be as expeditiously as practicable but no later
than the end of the tenth calendar year beginning after the area's
designation as nonattainment. . . .'' The EPA designated the South
Coast as nonattainment for the 2012 annual PM<INF>2.5</INF> NAAQS
effective April 15, 2015 (80 FR 2206, January 15, 2015). Therefore,
the latest permissible attainment date under CAA section 188(c)(2),
for purposes of the 2012 annual PM<INF>2.5</INF> NAAQS in this area,
is December 31, 2025.
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The EPA has defined BACM in the PM<INF>2.5</INF> SIP Requirements
Rule to mean ``any technologically and economically feasible control
measure that can be implemented in whole or in part within 4 years
after the date of reclassification of a Moderate PM<INF>2.5</INF>
nonattainment area to Serious and that generally can achieve greater
permanent and enforceable emissions reductions in direct
PM<INF>2.5</INF> emissions and/or emissions of PM<INF>2.5</INF> plan
precursors from sources in the area than can be achieved through the
implementation of RACM on the same source(s). BACM includes BACT.''
\27\
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\27\ 40 CFR 51.1000 (definitions). In longstanding guidance, the
EPA has similarly defined BACM to mean, ``among other things, the
maximum degree of emissions reduction achievable for a source or
source category, which is determined on a case-by-case basis
considering energy, environmental, and economic impacts.''59 FR
41998, 42010 and 42013 (August 16, 1994).
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Consistent with longstanding EPA guidance,\28\ the preamble to the
PM<INF>2.5</INF> SIP Requirements Rule discusses the following steps
for determining BACM and BACT:
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\28\ 59 FR 41998 (August 16, 1994).
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(1) Develop a comprehensive emission inventory of the sources of
PM<INF>2.5</INF> and PM<INF>2.5</INF> precursors;
(2) Identify potential control measures;
(3) Determine whether an available control measure or technology is
technologically feasible;
(4) Determine whether an available control measure or technology is
economically feasible; and
(5) Determine the earliest date by which a control measure or
technology can be implemented in whole or in part.\29\
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\29\ 81 FR 58010, 58083 through 58085 (August 24, 2016).
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The EPA allows consideration of factors such as physical plant
layout, energy requirements, needed infrastructure, and workforce type
and
[[Page 35449]]
habits when considering technological feasibility. For purposes of
evaluating economic feasibility, the EPA allows consideration of
factors such as the capital costs, operating and maintenance costs, and
cost effectiveness (i.e., cost per ton of pollutant reduced by a
measure or technology) associated with the measure or control.\30\
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\30\ 40 CFR 51.1010(a)(3) and 81 FR 58010, 58041 and 58042
(August 24, 2016).
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2. Comply With All Requirements and Commitments in the Applicable
Implementation Plan
A second precondition for an extension of the Serious area
attainment date under CAA section 188(e) is a showing that the state
has complied with all requirements and commitments pertaining to that
area in the implementation plan. We interpret this criterion to mean
that the state has implemented the control measures and commitments in
the SIP revisions it has submitted to address the applicable
requirements in CAA sections 172 and 189 for that particular
PM<INF>2.5</INF> nonattainment area; in this case, the South Coast
nonattainment area for the 2012 annual PM<INF>2.5</INF> NAAQS.\31\ For
a Serious area attainment date extension request submitted
simultaneously with the initial Serious area attainment plan for the
area, the EPA interprets CAA section 188(e) not to require the area to
have a fully approved Moderate area attainment plan, and to allow for
extension of the attainment date if the area has complied with all
Moderate area requirements and commitments pertaining to that area in
the State's submitted Moderate area implementation plan.\32\ This
interpretation is based on the plain language of CAA section 188(e),
which requires the state to comply with all requirements and
commitments pertaining to the area in the implementation plan.\33\
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\31\ Although the EPA has previously interpreted this
requirement as applying to additional PM<INF>2.5</INF> NAAQS for the
same area (see 85 FR 17382, 17405), this position is not required by
the statute or our regulations, and the EPA no longer believes that
this interpretation is the best available reading of the Act. The
EPA maintains that the implementation of a plan developed for an
entirely separate NAAQS should not have an impact on the relevant
requirements for the NAAQS at issue. There is no indication that
Congress intended such an additional hurdle for areas that are in
nonattainment for multiple NAAQS. Accordingly, the EPA believes that
the best interpretation of the statute is that ``compliance with all
requirements and commitments pertaining to that area in the
implementation plan'' refers only to the implementation plan for the
particular NAAQS at issue.
\32\ 81 FR 58010, 58095 (August 24, 2016).
\33\ The Ninth Circuit Court of Appeals upheld this
interpretation of CAA section 188(e) in Vigil v. Leavitt, 366 F.3d
1025, amended at 381 F.3d 826 (9th Cir. 2004).
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3. Demonstrate the Inclusion of the Most Stringent Measures
A third precondition for an extension of the Serious area
attainment under CAA section 188(e) is for the state to demonstrate to
the satisfaction of the Administrator that the plan for the area
includes the MSM that are included in the implementation plan of any
State, or are achieved in practice in any State, and can feasibly be
implemented in the area. The EPA has defined the term MSM as ``any
permanent and enforceable control measure that achieves the most
stringent emissions reductions in direct PM<INF>2.5</INF> emissions
and/or emissions of PM<INF>2.5</INF> plan precursors from among those
control measures which are either included in the SIP for any other
NAAQS, or have been achieved in practice in any state, and that can
feasibly be implemented in the relevant PM<INF>2.5</INF> NAAQS
nonattainment area.'' \34\ The EPA has interpreted the Act to require
implementation of MSM as expeditiously as practicable and no later than
one year before the extended Serious area attainment date identified by
the state in its extension request.\35\
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\34\ 40 CFR 51.1000 and 81 FR 58010, 58096 and 58097 (August 24,
2016); see also 59 FR 41998, 42010 (August 16, 1994) and 65 FR
19964, 19968 (April 13, 2000).
\35\ 81 FR 58010, 58097 (August 24, 2016).
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An MSM demonstration must satisfy the requirements of the
PM<INF>2.5</INF> SIP Requirements Rule as described in the preamble to
the rule, as follows: \36\
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\36\ 40 CFR 51.1010(b) and 81 FR 58010, 58095 through 58097
(August 24, 2016).
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(1) Update the emission inventory to identify all sources of direct
PM<INF>2.5</INF> and all PM<INF>2.5</INF> precursor emissions in the
nonattainment area;
(2) Identify all potential MSM to reduce emissions from sources of
direct PM<INF>2.5</INF> and PM<INF>2.5</INF> plan precursors that are
approved into any state implementation plan or used in practice in any
state;
(3) Compare the potential MSM for each relevant source category to
the measures, if any, already adopted for that source category in the
nonattainment area to determine whether such potential MSM would
further reduce emissions and, where the state chooses to reject a
measure from further consideration, demonstrate that it is not
technologically or economically feasible to implement the measure in
whole or in part within five years after the applicable attainment date
for the area; and
(4) Adopt and implement all potential MSM identified through this
process that collectively will achieve attainment as expeditiously as
practicable and no later than five years after the applicable
attainment date, except those measures for which the state has provided
reasoned justification for rejection, based on technological or
economic feasibility.
Notably, the ``to the satisfaction of the Administrator'' qualifier
on the MSM requirement is an explicit grant by Congress to the EPA of
discretion to determine whether a plan includes MSM.
4. Submit a Demonstration of Attainment by the Most Expeditious
Alternative Date Practicable
Section 189(b)(1)(A) of the Act requires that the State submit a
demonstration of attainment, including air quality modeling, by the
most expeditious date practicable after the statutory Serious area
attainment date.\37\ CAA section 188(e) states that the threshold
requirement is submission of such a demonstration.\38\ Accordingly, the
EPA must evaluate whether the submission containing the extension
request also includes such a demonstration.
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\37\ Id. at 58097.
\38\ The CAA does not require the EPA to act on the submitted
attainment demonstration as a precondition to granting an extension.
Section 188(e) of the Act states that ``[a]t the time of such
application, the State must submit a revision to the implementation
plan that includes a demonstration of attainment by the most
expeditious alternative date practicable.'' In particular, the
statute provides that ``[t]he Administrator may not approve an
extension until the State submits an attainment demonstration for
the area.''
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5. Apply for an Attainment Date Extension
Finally, the state must apply in writing to the EPA for an
extension of a Serious area attainment date, and this request must
accompany the submission of the modeled attainment demonstration
showing attainment by the most expeditious alternative date
practicable. Additionally, the state must provide the public reasonable
notice and opportunity for a public hearing on the attainment date
extension request before submitting it to the EPA in accordance with
the requirements for SIP revisions in CAA section 110.
IV. Review of the South Coast PM<INF>2.5</INF> Extension Application
In this section of the preamble, we present our evaluation of the
State's request to extend the Serious area
[[Page 35450]]
attainment date from December 31, 2025, to December 31, 2030, under CAA
section 188(e).
A. Demonstration That Attainment by Serious Area Attainment Date Is
Impracticable
The 2024 South Coast PM<INF>2.5</INF> Plan includes a
demonstration, based on air quality modeling, that even with the
implementation of BACM and BACT for all appropriate sources, attainment
by December 31, 2025, is not practicable. The impracticability
demonstration is included in Chapter 6 (``Federal Clean Air Act
Requirements'') of the 2024 South Coast PM<INF>2.5</INF> Plan, which
references the State's modeling results in Chapter 5 (``Future Air
Quality'') of the Plan. The BACM/BACT demonstration is included in
Appendix III (``Stationary and Mobile Source BACM/MSM''). Because of
the substantial overlap in the source categories and controls evaluated
for BACM and those evaluated for MSM, the BACM demonstration is
discussed alongside our evaluation of the Plan's MSM demonstration in
section IV.C of this document.
Table 5-4 of the Plan presents base year and modeled 2025 annual
PM<INF>2.5</INF> design values at 17 PM<INF>2.5</INF> monitoring sites
in the South Coast nonattainment area. The demonstration is summarized
in table 1 of this document.
Table 1--Impracticability Demonstration, Annual PM2.5 Design Value
Concentrations
[[micro]g/m\3\]
------------------------------------------------------------------------
2018 (base 2025
Monitoring site year) (projected)
------------------------------------------------------------------------
Anaheim................................. 10.54 10.22
Azusa................................... 10.13 9.7
Big Bear................................ 6.34 5.87
Los Angeles............................. 11.96 11.48
Compton................................. 12.25 11.89
Fontana................................. 11.35 10.66
Long Beach Near-Road.................... 12.28 11.95
Long Beach.............................. 10.53 10.25
Mira Loma............................... 13.52 12.62
Mission Viejo........................... 7.95 7.61
Ontario Near-Road....................... 13.98 13.09
Pasadena................................ 9.68 9.31
Pico Rivera............................. 11.87 11.48
Reseda.................................. 9.73 9.06
Riverside............................... 12.13 11.35
South Long Beach........................ 10.57 10.31
San Bernardino.......................... 10.88 10.12
------------------------------------------------------------------------
Source: 2024 South Coast PM2.5 Plan, Chapter 5, Table 5-4.
The State projected that the annual design value in the South Coast
nonattainment area in 2025 would be 13.09 [micro]g/m\3\, which is
substantially above the 12.0 [micro]g/m\3\ level of the 2012 annual
PM<INF>2.5</INF> NAAQS. Thus, we find it reasonable to conclude based
on the State's evaluation that attainment by the end of 2025 was
impracticable.
In addition to the information in the South Coast PM<INF>2.5</INF>
Plan, we have reviewed recent PM<INF>2.5</INF> monitoring data from the
South Coast Air Basin. These data show that annual average
PM<INF>2.5</INF> levels in the South Coast remained above the 12.0
[micro]g/m\3\ level of the 2012 annual PM<INF>2.5</INF> NAAQS in 2024
at eight monitoring sites in the South Coast nonattainment area.\39\
Furthermore, based on monitored ambient PM<INF>2.5</INF> air quality
data from 2023 and 2024, we calculated the maximum 2025 annual average
concentration that would result in an attaining 2025 design value \40\
at the historical design value site in the nonattainment area,\41\ and
compared this concentration to the lowest recorded annual average since
2012. This comparison is shown in table 2 below.
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\39\ EPA, AQS Design Value Report (AMP480), Report Request ID:
2371760, April 13, 2026. As of the time that this proposed
rulemaking was being prepared, 2024 was the most recent year for
which certified ambient air quality data were available.
\40\ An attaining design value for the 2012 annual
PM<INF>2.5</INF> NAAQS corresponds to a 3-year average
PM<INF>2.5</INF> concentration of 12.04 [micro]g/m\3\, accounting
for rounding conventions.
\41\ The historical design value site in the South Coast
nonattainment area, i.e., the site with, historically, the highest
monitored design value in the area, is the Ontario-Route 60 Near
Road monitor.
Table 2--Impracticability Demonstration, Annual PM2.5 Monitoring Data Assessment
----------------------------------------------------------------------------------------------------------------
Maximum 2025
annual average Lowest recorded
2023 Annual 2024 Annual PM2.5 annual average
average PM2.5 average PM2.5 concentration PM2.5
Site name concentration concentration resulting in concentration 2012-
([micro]g/m\3\) ([micro]g/m\3\) attaining 2025 2024 ([micro]g/
design value m\3\)
([micro]g/m\3\)
----------------------------------------------------------------------------------------------------------------
Ontario-Route 60 Near Road (06- 12.3 14.3 9.5 12.2
071-0027)......................
----------------------------------------------------------------------------------------------------------------
Sources: EPA, AQS Design Value Report (AMP480), Report Request ID: 2371760, April 13, 2026; and EPA, AQS Design
Value Report (AMP480), Report Request ID: 2372245, April 13, 2026.
[[Page 35451]]
The EPA's monitoring analysis determined that the maximum 2025
annual average concentration that would result in an attaining 2025
design value at the historical design value site in the nonattainment
area is 9.5 [micro]g/m\3\, approximately 33 percent below the monitored
annual average PM<INF>2.5</INF> concentration from the previous year,
and approximately 22 percent lower than the lowest annual average
PM<INF>2.5</INF> concentration recorded at this site since it was
established in 2015. Although the certified data for 2025 are not yet
available, the available data indicate that it is infeasible for the
area to attain by the December 31, 2025 attainment date.
Thus, our review of the State's impracticability demonstration and
of the available ambient air quality data indicate that the South Coast
area could not practicably have attained the 2012 annual
PM<INF>2.5</INF> NAAQS by the applicable attainment date of December
31, 2025.
B. Compliance With All Requirements and Commitments in the
Implementation Plan
We interpret this criterion to mean that the State has implemented
the control measures and commitments in the plan revisions it has
submitted to address the applicable requirements in CAA sections 172
and 189 for the relevant PM<INF>2.5</INF> NAAQS for the nonattainment
area.\42\ For the South Coast for the 2012 annual PM<INF>2.5</INF>
NAAQS, the State has submitted, and the EPA has approved into the
California SIP, the control measure requirements and commitments in the
2016 PM<INF>2.5</INF> Plan that pertained to the Moderate area planning
requirements for the 2012 annual PM<INF>2.5</INF> NAAQS. In the
remainder of this section, we describe the State's and District's
implementation of those control measures and commitments.
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\42\ 81 FR 58010, and 58094 (August 24, 2016). Under 40 CFR
51.1005(b)(1)(ii), a State must have complied with all requirements
and commitments in the applicable implementation plan. The EPA's
regulations provide that the applicable attainment plan for a
Serious PM<INF>2.5</INF> nonattainment area for which a state seeks
an attainment date extension under 40 CFR 51.1004(a)(2)(ii) is the
Moderate area plan submitted to meet the requirements of 40 CFR
51.1003(a). 40 CFR 51.1005(b)(3).
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As discussed in section I of this document, CARB submitted the 2016
PM<INF>2.5</INF> Plan to the EPA on April 27, 2017.\43\ On November 9,
2020, the EPA approved all but the contingency measure element of the
submitted SIP revision as meeting all applicable Moderate area
requirements for the 2012 annual PM<INF>2.5</INF> NAAQS, and
conditionally approved the contingency measure element as meeting the
Moderate area contingency measure requirement.\44\ The State
subsequently withdrew those portions of the 2016 PM<INF>2.5</INF> Plan
pertaining to the Serious area planning requirements for the 2012
annual PM<INF>2.5</INF> NAAQS, including those commitments intended to
meet the Serious area plan requirements.
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\43\ Letter dated April 27, 2017, from Richard Corey, Executive
Officer, CARB, to Alexis Strauss, Acting Regional Administrator, EPA
Region IX (transmitting the ``Final 2016 Air Quality Management Plan
(March 2017)'') (submitted electronically April 27, 2017).
\44\ 85 FR 71264 (November 9, 2020).
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A majority of the emission reductions needed to demonstrate RFP in
the South Coast nonattainment area in the 2016 PM<INF>2.5</INF> Plan
came from rules and regulations that were adopted prior to the
submittal of the Plan in April 2017. However, the State determined as
part of its RFP analysis for the 2016 PM<INF>2.5</INF> Plan that an
additional 7 tons per day (tpd) of NO<INF>X</INF> emission reductions
from new or revised control strategy measures was necessary to show
linear progress towards attainment by the Serious area attainment date
and thereby meet the 2022 RFP milestone.\45\ As part of the EPA's
November 9, 2020 final action on the 2016 PM<INF>2.5</INF> Plan, the
EPA approved, among other things, the District's commitment to achieve
7 tpd of direct PM<INF>2.5</INF> emission reductions from these or
substitute measures by the 2022 RFP milestone year.\46\
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\45\ 85 FR 40026, 40045 (July 2, 2020) and 2016 PM<INF>2.5</INF>
Plan, Table VI-C-6.
\46\ 85 FR 40026, 40035 and 40040 (July 2, 2020).
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Additionally, for purposes of meeting the Moderate area RFP
contingency measure requirement for the 2012 annual PM<INF>2.5</INF>
NAAQS,\47\ the District and CARB committed to develop, adopt, and
submit a revised District rule, SCAQMD Rule 445, ``Wood-Burning
Devices'' (``Rule 445''). The EPA conditionally approved the
contingency measure element of the 2016 PM<INF>2.5</INF> Plan,
including the State's commitment to revise Rule 445, as meeting the
Moderate area planning requirements for contingency measures for the
2012 annual PM<INF>2.5</INF> NAAQS.
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\47\ The EPA's proposal to approve the Moderate area plan and
impracticability demonstration for the South Coast for the 2012
annual PM<INF>2.5</INF> NAAQS explained that because we were
proposing to approve the State's demonstration that the South Coast
area could not practicably attain the 2012 annual PM<INF>2.5</INF>
NAAQS by the applicable Moderate area attainment date and to
reclassify the area to Serious, attainment contingency measures were
not required as part of the Moderate area plan. Additionally, with
respect to RFP contingency measures, we explained that the State's
2019 quantitative milestone report demonstrated that the actual
emission levels in 2019 were consistent with the approved 2019 RFP
milestone year targets for direct PM<INF>2.5</INF> and precursors.
Accordingly, we explained that RFP contingency measures for 2019 no
longer have meaning or purpose and proposed to find that the
requirement for them was moot as applied to the South Coast. The EPA
finalized these determinations as proposed. 85 FR 71264, 71266
(November 9, 2020).
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The State discusses compliance with the applicable 2016
PM<INF>2.5</INF> Plan Moderate area planning requirements and
commitments for the 2012 annual PM<INF>2.5</INF> NAAQS in Chapter 6
(``Federal Clean Air Act Requirements'') of the 2024 South Coast
PM<INF>2.5</INF> Plan.
Regarding the 7 tpd of NO<INF>X</INF> reductions needed to
demonstrate RFP in the 2022 milestone year, the District states that it
has achieved reductions in excess of those projected in the 2016
PM<INF>2.5</INF> Plan.\48\ Specifically, the District states that a
large portion of the reductions were achieved through mobile source
incentive measures under District control measure MOB-14 (``Emission
Reductions from Incentive Programs'').\49\ The incentive programs
include the Carl Moyer Program, Proposition 1B--Air Quality Improvement
Fund, the Lower-Emission School Bus Program, and the Community Air
Protection Program. Emission reductions from these programs are
summarized in Table 6-4 of the 2024 South Coast PM<INF>2.5</INF> Plan
and amount to 13.99 tpd of NO<INF>X</INF>, with reductions from the
Carl Moyer and Prop 1B programs alone exceeding the 7 tpd needed to
demonstrate RFP, totaling 11.39 tpd of NO<INF>X</INF> reductions.\50\
In addition to the reductions from incentive programs, the District
identified further surplus NO<INF>X</INF> reductions in 2022 from Rule
445; Rule 1109.1, ``NO<INF>X</INF> Emissions From Petroleum
Refineries;'' Rule 1179.1, ``Emission Reductions From Combustion
Equipment at Publicly Owned Treatment Works Facilities;'' and from the
general conformity set-aside account.\51\
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\48\ 2024 South Coast PM<INF>2.5</INF> Plan, p. 6-7.
\49\ Id.
\50\ Id. at Table 6-4. The EPA has previously reviewed the Carl
Moyer Program and Prop 1B Program guidelines and found that they
adequately address the EPA's recommended elements for economic
incentive programs and credited emissions reductions from these
programs towards the State's emissions reductions commitments (for
example, see 81 FR 53300 (August 12, 2016)).
\51\ Id. at Table 6-5.
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Regarding CARB's and the District's commitment to develop, adopt,
and submit a revised version of SCAQMD Rule 445, the District amended
Rule 445 for purposes of meeting the PM<INF>2.5</INF> contingency
measure commitment on June 5, 2020. On October 27, 2020, the District
made additional revisions to the rule while retaining the June 5, 2020
PM<INF>2.5</INF> contingency measure revisions
[[Page 35452]]
unchanged.\52\ The June 5, 2020 amendments to Rule 445 included the
addition of new lower mandatory wood-burning curtailment provisions in
section (f) (``PM<INF>2.5</INF> Contingency Measures'') to be
implemented as contingency measures upon a determination by the EPA
that any of the four ``findings of failure'' listed under 40 CFR
51.1014(a) has occurred.\53\ The EPA approved SCAQMD Rule 445, as
amended on October 27, 2020, except paragraph (g) (``Ozone Contingency
Measures'') and paragraph (k) (``Penalties''), into the California SIP
on March 8, 2022.\54\ We also determined that the submitted rule
fulfilled CARB's and the District's commitment to adopt and submit a
specific enforceable contingency measure to address CAA requirements
for the 2012 annual PM<INF>2.5</INF> NAAQS in the South Coast Air Basin
and, on that basis, converted our November 9, 2020 conditional approval
to a full approval.\55\
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\52\ SCAQMD Rule 445, as amended October 27, 2020. The District
adopted further amendments pertaining to ozone contingency measures
on October 27, 2020, but retained the Rule 445 amendments adopted
June 5, 2020, pertaining to PM<INF>2.5</INF> contingency measures,
unchanged.
\53\ Id.
\54\ 87 FR 12866, 12868 (March 8, 2022).
\55\ Id.
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Based on our review, we are proposing to find that the State has
complied with all the Moderate area requirements and commitments in the
2016 PM<INF>2.5</INF> Plan, which is the applicable implementation plan
for the purposes of 51.1005(b)(1)(ii) for the 2012 annual
PM<INF>2.5</INF> NAAQS.
C. Demonstration That the Implementation Plan Includes the Most
Stringent Measures
Before the EPA may extend the attainment date for a Serious
nonattainment area under CAA section 188(e), the state must, among
other things, demonstrate to the satisfaction of the Administrator that
the plan for the area includes the most stringent measures (MSM) that
are included in the implementation plan of any state or are achieved in
practice in any state, and can feasibly be implemented in the area. The
state must implement MSM as expeditiously as practicable and no later
than the beginning of the year containing the attainment date
identified by the state in its extension request, i.e., in this case,
by January 1, 2030.\56\ We interpret this criterion to mean that the
State must demonstrate to the EPA's satisfaction that its Serious area
plan includes the most stringent measures that are included in the
implementation plan of any state, or achieved in practice in any state,
and can feasibly be implemented in the area. The requirements that a
state's MSM evaluation must satisfy are described in the
PM<INF>2.5</INF> SIP Requirements Rule and are summarized in section
III of this document.
---------------------------------------------------------------------------
\56\ 81 FR 58010, 58097 (August 24, 2016).
---------------------------------------------------------------------------
The 2024 South Coast PM<INF>2.5</INF> Plan discusses the Plan's
control strategy, including compliance with the BACM and MSM
requirements, in Chapter 4 (``Control Strategy''), and contains BACM
and MSM evaluations in Appendix III (``Stationary and Mobile Source
BACM/MSM''). The evaluations consist of analyses by CARB and the
District of source categories under their respective jurisdictions.
Emissions inventories identifying sources of emissions of direct
PM<INF>2.5</INF> and PM<INF>2.5</INF> precursors \57\ in the South
Coast Air Basin are described and included in Chapter 3 (``Emissions
Inventory'') and Appendix I (``Base and Future Year Emission
Inventory'') of the Plan.
---------------------------------------------------------------------------
\57\ Appendix VI (``Precursor Demonstration'') of 2024 South
Coast PM<INF>2.5</INF> Plan contains a demonstration that emissions
of VOC and SO<INF>X</INF> do not contribute significantly to
exceedances of the 2012 annual PM<INF>2.5</INF> NAAQS in the South
Coast Air Basin and that such emissions should be excluded from
certain CAA requirements (including BACM and MSM), consistent with
the EPA's recommendations in the ``Fine Particulate Matter
(PM<INF>2.5</INF>) Precursor Demonstration Guidance'' (see
memorandum dated May 30, 2019, from Scott Mathias, Acting Director,
Air Quality Policy Division, EPA Office of Air Quality Planning and
Standards (OAQPS), and Richard Wayland, Director, Air Quality
Assessment Division, OAQPS, to Regional Air Division Directors,
Regions 1 -10, with attachment titled ``PM<INF>2.5</INF> Precursor
Demonstration Guidance;'' available at <a href="https://www.epa.gov/sites/default/files/2019-05/documents/transmittal_memo_and_pm25_precursor_demo_guidance_5_30_19.pdf">https://www.epa.gov/sites/default/files/2019-05/documents/transmittal_memo_and_pm25_precursor_demo_guidance_5_30_19.pdf</a>) The
BACM and MSM evaluations in the Plan therefore focus on sources of
emissions of direct PM<INF>2.5,</INF> NO<INF>X</INF>, and ammonia,
and exclude sources of VOC and SO<INF>X</INF>.
---------------------------------------------------------------------------
CARB's BACM/MSM analysis for sources under the State's jurisdiction
is contained in Attachment B (``Most Stringent Measures Analysis of
CARB's Control Programs'') to Appendix III of the 2024 South Coast
PM<INF>2.5</INF> Plan. CARB's four-step process to assess the State's
control program consists of: (1) identifying sources of direct
PM<INF>2.5</INF> emissions and precursor emissions; (2) identifying
potential control measures for the sources identified in Step 1; (3)
assessing the stringency and feasibility of the control measures
identified in Step 2; and (4) adopting and implementing the feasible
control measures identified in Step 3. CARB's demonstration includes
descriptions of CARB's key mobile source programs and regulations, and
a comprehensive evaluation of on-road and non-road mobile source
regulatory actions taken by CARB and other states. Based on its review,
CARB determined that its current control program for sources under its
jurisdiction satisfies the BACM and MSM requirements.\58\
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\58\ The Plan discusses CARB's commitments therein and in the
2016 State SIP Strategy and 2022 State SIP Strategy to adopt and
implement additional controls for mobile sources; however, these
controls are included for attainment purposes and largely identified
as ``beyond MSM'' due to stringency. The EPA will review these
measures in the context of the control strategy and attainment
demonstration in a future rulemaking.
---------------------------------------------------------------------------
The District followed a similar process to identify candidate BACM/
MSM measures that are technologically and economically feasible for
stationary and area sources under its jurisdiction. As a first step,
SCAQMD examined the emissions inventory to identify key sources of
emissions of direct PM<INF>2.5</INF>. Based on these inventories, the
District identified residential wood combustion, paved road dust,
commercial cooking, and farming operations--livestock waste as key
emission sources of direct PM<INF>2.5</INF> in the South Coast
nonattainment area.\59\ Next, the District broadened its analysis to
assess potential controls across all applicable source categories under
its jurisdiction. The District reviewed existing control measures
implemented in the South Coast Air Basin and compared those controls to
Federal and State regulations and guidance, as well as analogous rules
implemented by other air agencies to assess the stringency of existing
controls and identify potential opportunities to achieve further
reductions. More specifically, the District (1) conducted an in-depth
analysis of control measures in the SIPs for other 2012 annual
PM<INF>2.5</INF> NAAQS nonattainment areas (i.e., San Joaquin Valley,
CA; Plumas County, CA; Imperial County, CA; and Allegheny County, PA)
to evaluate whether control technologies deemed available and cost-
effective in those areas would be feasible in the South Coast Air
Basin; (2) reviewed EPA technical support documents for previously
adopted/amended rules submitted for approval into the California SIP;
(3) reevaluated control measures that the District had found to be
technologically or economically infeasible as part of the controls
evaluations in the 2016 and 2022 air quality management plans (AQMPs);
(4) reviewed the EPA's Menu of Control Measures; \60\ and (5) reviewed
[[Page 35453]]
the EPA's applicable guidance documents.
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\59\ 2024 South Coast PM<INF>2.5</INF> Plan, Appendix III, p.
III-3.
\60\ Available at <a href="https://www.epa.gov/air-quality-implementation-plans/menu-control-measures-naaqs-implementation">https://www.epa.gov/air-quality-implementation-plans/menu-control-measures-naaqs-implementation</a>.
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Based on its analysis, the District identified 15 control measures
for evaluation as potential BACM/MSM.\61\ The District's analyses
include descriptions of the measures, estimates of potential emissions
reductions and assessments of technological and economic feasibility.
As a result of these analyses, SCAQMD concluded that four of the
measures, identified in Table 4-4 of the Plan, are feasible and should
be adopted and implemented as MSM,\62\ and included commitments to
adopt each of these four measures as part of the control strategy of
the Plan.\63\ SCAQMD determined that the remaining measures were not
feasible for implementation in the South Coast Air Basin.
---------------------------------------------------------------------------
\61\ 2024 South Coast PM<INF>2.5</INF> Plan, Appendix III, p.
III-39.
\62\ While the District concluded that these measures are MSM,
they determined that they are not needed to meet BACM requirements.
\63\ 2024 South Coast PM<INF>2.5</INF> Plan, Table 4-4. The four
measures identified as MSM include BCM-08, ``Emissions Reductions
from Livestock Waste at Confined Animal Facilities;'' BCM-10,
``Emission Reductions from Direct Land Application of Chipped and
Ground Uncomposted Greenwaste;'' BCM-12, ``Further Emission
Reductions from Commercial Cooking;'' and BCM-18, ``Further Emission
Reductions from Wood Burning Fireplaces and Wood Stoves.'' See also
section titled ``Control Measure Assessment'' in Appendix III of the
2024 South Coast PM<INF>2.5</INF> Plan.
---------------------------------------------------------------------------
Based upon our review, the EPA has determined that the 2024 South
Coast PM<INF>2.5</INF> Plan contains the required elements of BACM and
MSM evaluations as described in the PM<INF>2.5</INF> SIP Requirements
Rule. The emissions inventory identifies all sources of emissions of
direct PM<INF>2.5</INF> and applicable PM<INF>2.5</INF> precursors. For
the source categories identified in the emissions inventory for the
nonattainment area, CARB and the District followed EPA guidance to
identify potential measures from other areas' control requirements for
similar sources, the EPA's technical support documents from rulemakings
on SCAQMD control measure SIP submittals, potential control measures
identified in previous SCAQMD plan submittals, the EPA's menu of
control measures, and EPA guidance documents.
Our review indicates that CARB and the District conducted thorough
analyses of emissions sources in the nonattainment area and potential
control measures for those sources. The 2024 South Coast
PM<INF>2.5</INF> Plan includes commitments and an expeditious schedule
for adopting the four measures identified by the District as MSM, and
provides a reasoned justification for the rejection of all other
potential MSM based on technological or economic feasibility,
consistent with the requirements established in the PM<INF>2.5</INF>
SIP Requirements Rule. The District has since adopted the four measures
and submitted them to the EPA for inclusion in the California SIP.\64\
The EPA is not aware of more stringent and feasible measures
implemented in other areas of the country beyond those identified in
the 2024 South Coast PM<INF>2.5</INF> Plan. Thus, our review indicates
that the 2024 South Coast PM<INF>2.5</INF> Plan includes the requisite
BACM demonstration and includes the MSM that are included in the
implementation plan of any state, or are achieved in practice in any
state, and can feasibly be implemented in the area.
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\64\ Letter dated February 4, 2026, from Steven S. Cliff,
Executive Officer, CARB, to Mike Martucci, Acting Regional
Administrator, EPA Region 9, submitting revisions to the California
SIP, including revisions to SCAQMD Rule 1133 series, ``Composting,
Chipping and Grinding, and Related Operations'' to regulate the
supply of uncomposted greenwaste for direct land application; SCAQMD
Rule 1138, ``Control of Emissions from Restaurant Operations'' to
lower the applicability threshold for chain-driven charbroilers;
SCAQMD Rule 223, ``Requirements for Confined Animal Facilities'' to
lower the applicability thresholds for dairy, chicken, and duck
farms and require permits to operate and emission mitigation plans
for facilities meeting the new definition of large confined animal
facility; and SCAQMD Rule 445, ``Wood-Burning Devices'' to lower the
curtailment threshold and remove the low-income household exemption
(submitted electronically February 10, 2026).
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D. Demonstration of Attainment by the Most Expeditious Alternative Date
Practicable
Section 188(e) of the Act states that at the time of its
application for an extension of an attainment deadline, the state must
submit a demonstration of attainment by the most expeditious
alternative date practicable, and that the EPA may not approve the
extension until such a demonstration has been submitted. Section
189(b)(1)(A)(ii) of the CAA also provides that a state seeking an
extension of the attainment date under CAA section 188(e) must submit a
demonstration that the plan provides for attainment by the most
expeditious alternative date practicable.
For the purpose of the CAA section 188(e) requirement that the
District submit a demonstration that the plan provides for attainment
by the most expeditious alternative date practicable, the EPA's review
of the submission indicates that the submission contains the requisite
demonstration. Chapter 5 (``Future Air Quality'') of the 2024 South
Coast PM<INF>2.5</INF> Plan contains the State's demonstration of
attainment by 2030, and an analysis concluding that attainment by 2029
would not be possible.\65\ While the EPA will evaluate this analysis in
a future rulemaking action, for the purpose of the CAA section 188(e)
extension prerequisite that a complete submission from the state must
contain the requisite demonstration under CAA section 189(b)(1)(A)(ii),
our review of the 2024 South Coast PM<INF>2.5</INF> Plan indicates that
the State has made such a submission.
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\65\ The submitted analysis states the conclusion that ``the
earliest attainment date of the annual PM<INF>2.5</INF> standard
would be in 2030.''
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E. Application for an Attainment Date Extension
As discussed in section I.B of this document, the Serious area
attainment date for the South Coast for the 2012 annual
PM<INF>2.5</INF> NAAQS under CAA section 188(c)(2) is December 31,
2025. The remaining criterion for an extension of the attainment date
beyond this statutory attainment date is that the State must apply for
such extension. In the 2024 South Coast PM<INF>2.5</INF> Plan, CARB and
SCAQMD submitted a complete application for an extension of the Serious
area attainment date for the South Coast to December 31, 2030, for the
2012 annual PM<INF>2.5</INF> NAAQS.\66\ In accordance with the
requirements of the PM<INF>2.5</INF> SIP Requirements Rule in 40 CFR
51.1005(b)(1), the State's submission includes demonstrations that
attainment by the Serious area attainment date is impracticable, that
the State has complied with all requirements and commitments in the
applicable SIP, and that the plan includes MSM. Additionally, in
accordance with 40 CFR 51.1005(b)(2), the 2024 South Coast
PM<INF>2.5</INF> Plan contains all of the required components of a
Serious area plan accompanying a request for extension of the
attainment date under CAA section 188(e), as follows: (1) base year and
attainment projected emissions inventories, (2) provisions to implement
MSM and BACM, (3) a modeled attainment demonstration, (4) reasonable
further progress provisions, (5) quantitative milestone provisions, (6)
contingency measure provisions, and (7) nonattainment new source review
plan provisions.\67\ As discussed in section II
[[Page 35454]]
of this document, the EPA previously found that the State provided the
public reasonable notice and an opportunity for a public hearing on the
2024 South Coast PM<INF>2.5</INF> Plan, including the attainment date
extension request, before submitting it to the EPA, in accordance with
the requirements for SIP revisions in CAA section 110.
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\66\ CARB Resolution 24-7 (June 27, 2024), (adopting the Plan
and directing the CARB Executive Officer to submit the Plan to the
EPA as a SIP revision), SCAQMD Governing Board Resolution 24-16
(June 7, 2024) (adopting the 2024 South Coast PM<INF>2.5</INF>
Plan), and 2024 South Coast PM<INF>2.5</INF> Plan, Ch. 6, p. 6-2.
\67\ Letter dated August 5, 2024, from Steven S. Cliff,
Executive Officer, CARB, to Martha Guzman, Regional Administrator,
EPA Region 9, with attachments (transmitting the adopted 2024 South
Coast PM<INF>2.5</INF> Plan to the EPA for inclusion in the
California SIP) (submitted electronically on August 6, 2024).
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F. Other Factors That the EPA May Consider
Finally, as noted section III of this document, CAA section 188(e)
lists five additional factors that the EPA may consider in deciding
whether to grant an attainment date extension and the length for such
extension. These factors include: (1) the nature and extent of the
nonattainment problem; (2) the types and numbers of sources or other
emitting activities in the area (including the influence of
uncontrollable natural sources and international transport); (3) the
population exposed to concentrations in excess of the standard; (4) the
presence and concentration of potentially toxic substances in the mix
of particulate emissions in the area; and (5) the technological and
economic feasibility of various control measures. In evaluating these
factors, we have focused on the nature and extent of the nonattainment
area problem and the technological and economic feasibility of
additional control measures.
The South Coast Air Basin has made significant progress towards
improving air quality and meeting the NAAQS despite challenges
associated with being one of the nation's largest urban areas and
meteorological conditions and mountainous terrain that tend to trap
pollutants in the Air Basin.\68\ In the years prior to the adoption of
the 2024 South Coast PM<INF>2.5</INF> Plan, CARB and the District
developed and implemented several comprehensive plans (e.g., the 2012
AQMP and 2016 AQMP) to provide for attainment of PM<INF>2.5</INF> and
ozone NAAQS. These plans have resulted in the adoption and
implementation of many new rules and amendments to existing rules
across source categories. These regulations and strategies have yielded
significant reductions from sources under the State's and District's
jurisdictions. As a result of these already-adopted State and District
measures, sources in the South Coast nonattainment area are already
subject to the most stringent rules in the country, leaving fewer and
more technologically challenging opportunities to reduce emissions, as
demonstrated by the controls analysis in the 2024 South Coast
PM<INF>2.5</INF> Plan.\69\ The State and District continue to pursue
new opportunities to achieve further reductions in direct
PM<INF>2.5</INF> and PM<INF>2.5</INF> precursor emissions, as outlined
in the Plan; \70\ however, the EPA acknowledges the scarcity of
additional controls and the timeline needed to develop, adopt, and
implement such measures. These factors generally support a longer time
frame for attainment.
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\68\ For a discussion of challenges and historical air quality
trends, see Chapter 2 (``Air Quality'') of the 2024 South Coast
PM<INF>2.5</INF> Plan.
\69\ 2024 South Coast PM<INF>2.5</INF> Plan, Chapter 4, Appendix
III, and Appendix IV.
\70\ Id.
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V. Summary of Proposed Action and Request for Public Comment
For the reasons discussed in this proposed rule, the EPA is
proposing to grant the State's request for an extension of the Serious
area attainment date from December 31, 2025, to December 31, 2030,
based on a conclusion that the State has satisfied the requirements for
such an extension in section 188(e) of the Act.
The EPA is soliciting public comments on the issues discussed in
this document. We will accept comments from the public on this proposal
for the next 30 days.
VI. Statutory and Executive Order Reviews
Additional information about these statutes and Executive Orders
can be found at <a href="https://www.epa.gov/laws-regulations/laws-and-executive-orders">https://www.epa.gov/laws-regulations/laws-and-executive-orders</a>.
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.
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 because this 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.
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.
G. Executive Order 13175: Coordination With Indian Tribal Governments
This action does not have Tribal implications, as specified in
Executive Order 13175, because 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, and will not
impose substantial direct costs on Tribal governments or preempt Tribal
law. Thus, Executive Order 13175 does not apply to this action.
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 to approve
a state request for an attainment date extension as meeting Federal
requirements. 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.
[[Page 35455]]
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 in 40 CFR Part 52
Environmental protection, Air pollution control, Ammonia,
Incorporation by reference, Intergovernmental relations, Nitrogen
dioxide, Particulate matter, Reporting and recordkeeping requirements,
Sulfur dioxide, Volatile organic compounds.
Authority: 42 U.S.C. 7401 et seq.
Dated: May 29, 2026.
Michael Martucci,
Acting Regional Administrator, Region IX.
[FR Doc. 2026-11736 Filed 6-10-26; 8:45 am]
BILLING CODE 6560-50-P
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This is legal information, not legal advice. Laws vary by jurisdiction and change frequently. Always verify current law with official sources and consult a licensed attorney in your jurisdiction for advice on your specific situation.