6560-50-P
ENVIRONMENTAL PROTECTION AGENCY
40 CFR Part 52
[EPA-R09-OAR-2024-0250; FRL-12006-01-R9]
Attainment Date Extension for the San Joaquin Valley, California 1997 Annual PM2.5 Fine
Particulate Matter Nonattainment Area
AGENCY: Environmental Protection Agency (EPA).
ACTION: Proposed rule.
SUMMARY: The Environmental Protection Agency (EPA) is proposing to grant a one-year
extension of the applicable “Serious” attainment date for the 1997 annual fine particulate matter
(PM2.5) San Joaquin Valley, California nonattainment area. This action is based on the EPA’s
evaluation of air quality monitoring data and the extension request submitted by the State of
California on May 23, 2024. The EPA is proposing to grant a one-year extension of the Serious
attainment date from December 31, 2023, to December 31, 2024, in accordance with section
172(a)(2)(C) of the Clean Air Act (CAA). We are taking comments on this proposal and plan to
follow with a final action.
DATES: Comments must be received on or before [Insert date 30 days after date of
publication in the FEDERAL REGISTER].
ADDRESSES: Submit your comments, identified by Docket ID No. EPA-R09-OAR-2024-0250
at https://www.regulations.gov. For comments submitted at Regulations.gov, follow the online
instructions for submitting comments. Once submitted, comments cannot be edited or removed
from Regulations.gov. The EPA may publish any comment received to its public docket. Do not
submit electronically any information you consider to be Confidential Business Information
(CBI) or other information whose disclosure is restricted by statute. Multimedia submissions
(audio, video, etc.) must be accompanied by a written comment. The written comment is
considered the official comment and should include discussion of all points you wish to make.

The EPA will generally not consider comments or comment contents located outside of the
primary submission (i.e., on the web, cloud, or other file sharing system). For additional
submission methods, please contact the person identified in the FOR FURTHER
INFORMATION CONTACT section. For the full EPA public comment policy, information
about CBI or multimedia submissions, and general guidance on making effective comments,
please visit https://www.epa.gov/dockets/commenting-epa-dockets. 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, EPA Region IX, 75
Hawthorne St., San Francisco, CA 94105; phone: (415) 972-3877; email:
graham.ashleyr@epa.gov.
SUPPLEMENTARY INFORMATION: Throughout this document, “we,” “us,” and “our”
refer to the EPA.
Table of Contents
I. Background
A. PM2.5 NAAQS
B. San Joaquin Valley PM2.5 Designations, Classifications, and SIP Revisions
C. CAA Requirements for an Attainment Date Extension
II. The State’s Request for an Extension
III. The EPA’s Evaluation
A. Compliance with the Applicable SIP
B. Air Quality Data
IV. Environmental Justice Considerations
V. The EPA’s Proposed Action
VI. Statutory and Executive Order Reviews
I.

Background

A. 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 the EPA should revise or establish new NAAQS to protect public health.

On July 18, 1997, the EPA revised the NAAQS for particulate matter by establishing new
NAAQS for particles with an aerodynamic diameter less than or equal to a nominal 2.5
micrometers (PM2.5).1 The EPA established primary and secondary annual and 24-hour standards
for PM2.5.2 The EPA set the annual primary and secondary standards at 15.0 micrograms per
cubic meter (μg/m3), based on a three-year average of annual mean PM2.5 concentrations, and set
the 24-hour primary and secondary standards at 65 μg/m3, based on the three-year average of the
98th percentile of 24-hour PM2.5 concentrations at each monitoring site within an area.3
Collectively, we refer herein to the 1997 annual and 24-hour PM2.5 NAAQS as the “1997 PM2.5
NAAQS.”
On October 17, 2006, the EPA revised the level of the 24-hour PM2.5 NAAQS to 35
μg/m3,4 and on January 15, 2013, the EPA revised the level of the primary annual PM2.5 NAAQS
to 12.0 μg/m3.5 On February 7, 2024, the EPA revised the level of the primary annual PM2.5
NAAQS once more to 9.0 μg/m3.6 Even though the EPA lowered the 24-hour and annual PM2.5
NAAQS, the 1997 24-hour PM2.5 NAAQS remain in effect and the 1997 primary annual PM2.5
NAAQS remains in effect in areas designated nonattainment for that NAAQS.7
The EPA established each of the PM2.5 NAAQS after considering substantial evidence
from numerous health studies demonstrating that serious health effects are associated with
exposures to PM2.5 concentrations above these levels. Epidemiological studies have shown
statistically significant correlations between elevated PM2.5 levels and premature mortality. Other
important health effects associated with PM2.5 exposure include aggravation of respiratory and
cardiovascular disease (as indicated by increased hospital admissions, emergency room visits,

62 FR 38652.
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).
3 40 CFR 50.7.
4 71 FR 61144.
5 78 FR 3086.
6 89 FR 16202.
7 40 CFR 50.13(d).
1
absences from school or work, and restricted activity dates), changes in lung function and
increased respiratory symptoms, and new evidence for more subtle indicators of cardiovascular
health. Individuals particularly sensitive to PM2.5 exposure include older adults, people with
heart and lung disease, and children.8
PM2.5 can be particles emitted by sources directly into the atmosphere as a solid or liquid
particle (“primary PM2.5” or “direct PM2.5”) or can be particles that form in the atmosphere as a
result of various chemical reactions from PM2.5 precursor emissions emitted by sources
(“secondary PM2.5”). The EPA has identified the precursors of PM2.5 to be oxides of nitrogen
(“NOX”), sulfur oxides (“SOX”), volatile organic compounds (“VOC”), and ammonia.9
B. San Joaquin Valley PM2.5 Designations, Classifications, and SIP Revisions
Following promulgation of a new or revised NAAQS, the EPA is required under CAA
section 107(d) to designate areas throughout the nation as attainment, nonattainment, or
unclassifiable for the NAAQS. Effective April 5, 2005, the EPA established the initial air quality
designations for the 1997 annual and 24-hour PM2.5 NAAQS, using air quality monitoring data
for the three-year periods of 2001–2003 and 2002–2004.10 The EPA designated the San Joaquin
Valley as nonattainment for both the 1997 annual PM2.5 NAAQS (15.0 µg/m3) and the 1997 24hour PM2.5 NAAQS (65 µg/m3).11
The San Joaquin Valley PM2.5 nonattainment area encompasses over 23,000 square miles
and includes all or part of eight counties: San Joaquin, Stanislaus, Merced, Madera, Fresno,
Tulare, Kings, and the valley portion of Kern.12 The area is home to four million people and is
one of the nation’s leading agricultural regions. Stretching over 250 miles from north to south
and averaging 80 miles wide, it is partially enclosed by the Coast Mountain range to the west, the

EPA, Air Quality Criteria for Particulate Matter, No. EPA/600/P–99/002aF and EPA/600/P–99/002bF, October
2004.
9 For example, see 72 FR 20586, 20589 (April 25, 2007).
10 70 FR 944 (January 5, 2005).
11 40 CFR 81.305.
12 For a precise description of the geographic boundaries of the San Joaquin Valley nonattainment area, see 40 CFR
81.305.
Tehachapi Mountains to the south, and the Sierra Nevada range to the east. Under State law, the
San Joaquin Valley Unified Air Pollution Control District (SJVUAPCD or “District”) has
primary responsibility for developing plans to provide for attainment of the NAAQS in this area.
The District works cooperatively with the California Air Resources Board (CARB) in preparing
attainment plans. Authority for regulating sources under State jurisdiction in the San Joaquin
Valley is split under State law between the District, which has responsibility for regulating
stationary and most area sources, and CARB, which has responsibility for regulating most
mobile sources.
At the time of the initial designations for the 1997 PM2.5 NAAQS, the EPA interpreted
the CAA to require implementation of the NAAQS under the general nonattainment plan
requirements of subpart 1.13 Under subpart 1, states were required to submit nonattainment plan
SIP submissions within three years of the effective date of designations that, among other things,
provided for implementation of reasonably available control measures (RACM), reasonable
further progress (RFP), contingency measures, and a modeled attainment demonstration showing
attainment of the NAAQS as expeditiously as practicable, but no later than five years from the
designation (in this instance, no later than April 5, 2010), unless the state justified an attainment
date extension of up to five years.14
Between 2007 and 2011, California submitted six nonattainment plan and supporting SIP
revisions to address nonattainment area planning requirements for the 1997 PM2.5 NAAQS in the
San Joaquin Valley,15 which we refer to collectively as the “2008 PM2.5 Plan.” On November 9,
2011, the EPA approved the portions of the 2008 PM2.5 Plan, as revised in 2009 and 2011, that
addressed attainment of the 1997 PM2.5 NAAQS in the San Joaquin Valley nonattainment area,
except for the attainment contingency measures, which we disapproved.16 We also granted the

72 FR 20586.
CAA sections 172(a)(2), 172(c)(1), 172(c)(2), and 172(c)(9).
15 76 FR 69896, n. 2 (November 9, 2011).
16 Id. at 69924.
13
State’s request to extend the attainment deadline for the 1997 PM2.5 NAAQS in the San Joaquin
Valley to April 5, 2015.17
Following a January 4, 2013 decision of the U.S. Court of Appeals for the D.C. Circuit
remanding the EPA’s 2007 implementation rule for the 1997 PM2.5 NAAQS,18 the EPA
published a final rule on June 2, 2014, classifying the San Joaquin Valley as a “Moderate”
nonattainment area for the 1997 PM2.5 NAAQS under subpart 4, part D of title I of the Act.19 In
that action, the EPA acknowledged that states must meet both subpart 1 and subpart 4
requirements in nonattainment plan SIP submissions for the 1997 24-hour and annual PM2.5
NAAQS and provided states with additional time to supplement or withdraw and resubmit any
pending nonattainment plan SIP submissions.
Effective May 7, 2015, the EPA reclassified the San Joaquin Valley as a Serious
nonattainment area for the 1997 PM2.5 NAAQS based on our determination that the State could
not practicably attain these NAAQS in the San Joaquin Valley nonattainment area by the latest
statutory Moderate area attainment date, i.e., April 5, 2015.20 Upon reclassification as a Serious
area, the State became subject to the requirement of CAA section 188(c)(2) to attain the 1997
PM2.5 NAAQS as expeditiously as practicable but no later than ten years after designation, i.e.,
by no later than December 31, 2015. California submitted its Serious area plan for the 1997
PM2.5 NAAQS for the San Joaquin Valley in two submissions dated June 25, 2015, and August
13, 2015, including a request under section 188(e) to extend the attainment date for the 1997 24hour PM2.5 NAAQS by three years (to December 31, 2018) and to extend the attainment date for
the 1997 annual PM2.5 NAAQS by five years (to December 31, 2020). On February 9, 2016, the
Id.
Natural Resources Defense Council v. EPA, 706 F.3d. 428 (DC Cir. 2013) (“NRDC”). In NRDC, the court held
that the EPA erred in implementing the 1997 PM2.5 NAAQS solely pursuant to the general implementation
requirements of subpart 1, without also considering the requirements specific to nonattainment areas for particles
less than or equal to 10 µm in diameter (PM10) in subpart 4, part D of title I of the CAA. The court reasoned that the
plain meaning of the CAA requires implementation of the 1997 PM2.5 NAAQS under subpart 4 because PM2.5 falls
within the statutory definition of PM10 and is thus subject to the same statutory requirements as PM10. The court
remanded the rule, without vacatur, and instructed the EPA “to repromulgate these rules pursuant to Subpart 4
consistent with this opinion.”
19 79 FR 31566.
20 80 FR 18528 (April 7, 2015).
17
EPA proposed to approve most of the Serious area plan and to grant the State’s request for
extensions of the December 31, 2015 attainment date.21 However, on October 6, 2016, after
considering public comments, the EPA denied California’s request for these extensions of the
attainment dates.22 Consequently, on November 23, 2016, the EPA determined that the San
Joaquin Valley had failed to attain the 1997 24-hour and annual PM2.5 NAAQS by the December
31, 2015 Serious area attainment date.23 This determination triggered a requirement for
California to submit a new SIP submission for the 1997 24-hour and annual PM2.5 NAAQS for
the San Joaquin Valley that satisfies the requirements of CAA section 189(d). The statutory
deadline for this additional SIP submission was December 31, 2016. The EPA did not finalize
the actions proposed on February 9, 2016, with respect to the submitted Serious area plan.24
On December 6, 2018, the EPA determined that California had failed to submit a
complete section 189(d) attainment plan for the 1997 24-hour and annual PM2.5 NAAQS, among
other required SIP submissions for the San Joaquin Valley, by the statutory deadlines.25 This
finding, which became effective on January 7, 2019, triggered clocks under CAA section 179(a)
for the application of emissions offset sanctions 18 months after the finding, 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.26 The
finding 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 submitted,
and the EPA approved, the required SIP submission.27
On May 10, 2019, CARB submitted the “2018 Plan for the 1997, 2006, and 2012 PM2.5

81 FR 6936. California’s request for extension of the Serious Area attainment date for the San Joaquin Valley
accompanied its Serious Area attainment plan for the 1997 PM2.5 NAAQS and related motor vehicle emissions
budgets, submitted June 25, 2015, and August 13, 2015, respectively.
22 81 FR 69396.
23 81 FR 84481.
24 81 FR 69396, 69400.
25 83 FR 62720.
26 Id. at 62723.
27 Id.
Standards,” adopted by the SJVUAPCD on November 15, 2018, and by CARB on January 24,
2019 (“2018 PM2.5 Plan”).28 The 2018 PM2.5 Plan addressed the Serious area nonattainment plan
and CAA section 189(d) requirements for the 1997 24-hour and annual PM2.5 NAAQS, among
other requirements for the 2006 and 2012 PM2.5 NAAQS. CARB clarified in its submittal letter
that the 2018 PM2.5 Plan superseded past submissions to the EPA that the agency had not yet
acted on for the 1997 PM2.5 NAAQS, including the 2015 Serious area attainment plan
submissions.29 On June 24, 2020, the EPA issued a letter finding these submissions complete and
terminating the sanctions clocks under CAA section 179(a).30
On January 28, 2022, the EPA approved those portions of the 2018 PM2.5 Plan that
pertain to the 1997 24-hour PM2.5 NAAQS, except for the contingency measure element, which
the EPA disapproved.31 As part of that action, the EPA also finalized a determination that the
San Joaquin Valley attained the 1997 24-hour PM2.5 NAAQS by the applicable attainment date
of December 31, 2020, and that therefore the requirement for contingency measures no longer
applies in the San Joaquin Valley nonattainment area for the 1997 24-hour PM2.5 NAAQS.32
On July 22, 2021, the EPA proposed to partially approve and partially disapprove
portions of the 2018 PM2.5 Plan that addressed attainment of the 1997 annual PM2.5 NAAQS in
the San Joaquin Valley nonattainment area.33 The EPA proposed to approve the 2013 base year
emissions inventories and disapprove the attainment demonstration and related elements,
including the comprehensive precursor demonstration, five percent annual emissions reductions
demonstration, best available control measures (BACM) demonstration, RFP demonstration,
quantitative milestones, and motor vehicle emissions budgets established for 2017, 2020, and
Letter dated May 9, 2019, from Richard Corey, Executive Officer, CARB, to Mike Stoker, Regional
Administrator, EPA Region 9.
29 The 2015 Serious area attainment plan submissions include the “2015 Plan for the 1997 Standard” (submitted by
CARB on June 25, 2015) and motor vehicle emissions budgets (submitted by CARB August 13, 2015).
30 Letter dated June 24, 2020, from Elizabeth J. Adams, Director, Air and Radiation Division, EPA Region IX, to
Richard Corey, Executive Officer, CARB, Subject: “RE: Completeness Finding for State Implementation Plan (SIP)
Submissions for San Joaquin Valley for the 1997, 2006, and 2012 Fine Particulate Matter (PM2.5) National Ambient
Air Quality Standards (NAAQS) and Termination of Clean Air Act (CAA) Sanction Clocks.”
31 87 FR 4503 (January 28, 2022).
32 Id. at 4506.
33 86 FR 38652.
2023. We proposed to disapprove the attainment demonstration and related elements because
certified air quality data were available that established that the San Joaquin Valley area did not
attain the 1997 annual PM2.5 NAAQS by December 31, 2020, as projected in the 2018 PM2.5
Plan. On November 26, 2021, the EPA finalized the partial approval and partial disapproval of
the 2018 PM2.5 Plan for the 1997 annual PM2.5 NAAQS as proposed.34
As a result of the November 26, 2021 disapprovals, California was required to develop
and submit a revised attainment plan for the San Joaquin Valley area that addressed the
applicable CAA requirements, including the Serious area plan requirements and the requirements
of CAA section 189(d), for the 1997 annual PM2.5 NAAQS. In accordance with sections
179(d)(3) and 172(a)(2) of the CAA, the revised plan was required to demonstrate attainment of
these NAAQS as expeditiously as practicable and no later than 5 years from the date of the
EPA’s prior determination that the area failed to attain (i.e., by November 23, 2021), except that
the EPA could extend the attainment date to a date no later than 10 years from the failure to
attain determination (i.e., to November 23, 2026), “considering the severity of nonattainment and
the availability and feasibility of pollution control measures.”35
On November 8, 2021, CARB submitted the “Attainment Plan Revision for the 1997
Annual PM2.5 Standard” (“15 µg/m3 SIP Revision”), adopted by the SJVUAPCD on August 19,
2021, and adopted by CARB on September 23, 2021.36 In the letter accompanying the
submission, CARB clarified that the 15 µg/m3 SIP Revision amended the 2018 PM2.5 Plan.37
On December 14, 2023, the EPA approved the 15 µg/m3 SIP Revision as a revision to the
California SIP, establishing an applicable attainment date of December 31, 2023, for the 1997

86 FR 67329.
81 FR 84481, 84482 (final EPA action determining that the San Joaquin Valley had failed to attain the 1997 PM2.5
NAAQS by the December 31, 2015, Serious area attainment date).
36 Letter dated November 8, 2021, from Richard W. Corey, Executive Officer, CARB, to Deborah Jordan, Acting
Regional Administrator, EPA Region 9. The 15 µg/m3 SIP Revision was developed jointly by CARB and the
District.
37 Id. at 1.
34
annual PM2.5 NAAQS in the San Joaquin Valley.38
C. CAA Requirements for an Attainment Date Extension
Under CAA section 172(a)(2)(C), the EPA may grant a state’s request to extend the
attainment date established under CAA section 172(a)(2)(A) if: “(1) the State has complied with
all requirements and commitments pertaining to the area in the applicable implementation plan,
and (2) in accordance with guidance published by the Administrator, no more than the minimal
number of exceedances of the relevant national ambient air quality standard has occurred in the
area in the year preceding the Extension Year.” The EPA may grant a second 1-year extension if
these same criteria are met at the end of the first extension year. The EPA cannot issue more than
two one-year extensions under section 172(a)(2)(C) for a single nonattainment area.
In an August 24, 2016 final rule entitled, “Fine Particulate Matter National Ambient Air
Quality Standards: State Implementation Plan Requirements” (“PM2.5 SIP Requirements Rule”),
the EPA established regulatory requirements and provided further interpretive guidance on the
statutory SIP requirements that apply to areas designated nonattainment for the PM2.5 NAAQS,39
including guidance on the extension provisions for particulate matter nonattainment areas under
CAA section 188. Because CAA section 188(d) is nearly identical to CAA section 172(a)(2)(C),
the EPA considers the guidance pertaining to the one-year extension requirements under CAA
section 188(d) to persuasively inform the requirements for a one-year extension for a particulate
matter nonattainment area under CAA section 172(a)(2)(C). Thus, our assessment of the State’s
extension request will rely on the guidance for one-year extensions under CAA section 188(d).
With regard to the first criterion for an extension of the attainment date, the EPA clarified
in the PM2.5 SIP Requirements Rule that a state must show that it has “submitted the necessary
attainment plan for the area for the applicable PM2.5 NAAQS and is implementing the control

88 FR 86581. As discussed in the EPA’s proposal to approve the 15 µg/m3 SIP Revision, the attainment date for
the 189(d) plan was established consistent with CAA sections 179(d)(3) and 172(a)(2).
39 81 FR 58010.
measures in the submission.”40 The EPA interprets this requirement to mean that a state must
have adopted and be implementing the control measures and commitments in the approved SIP
revisions it has submitted to address the CAA requirements for the applicable PM2.5 NAAQS.41
With regard to the second criterion, the EPA explains in the PM2.5 SIP Requirements
Rule that we interpret that “a state seeking an attainment date extension for an annual PM2.5
NAAQS would be required to demonstrate that the area had clean data for that particular
standard…in the calendar year prior to the applicable attainment date for the area…”42 That is,
for the 1997 annual PM2.5 NAAQS, a state would need to show that the annual mean value in the
year proceeding the attainment year (in this case, 2023) did not exceed the 15.0 µg/m3 level of
the standard.
If the EPA finds that a state has satisfied the criteria for an extension and grants an
extension of the attainment date, the EPA must determine whether the area attained the relevant
NAAQS following the end of the extension year (unless the state requests a second one-year
extension and the EPA finds that the requirements for such extension are satisfied and extends
the attainment date by an additional year). In the absence of an attainment date extension, upon a
determination of failure to attain by the EPA, the state would be required to develop a revised
attainment plan for the area.
II. The State’s Request for an Extension
As discussed in Section I.B of this document, on December 14, 2023, the EPA approved
California’s plan to address the Serious area and CAA section 189(d) plan requirements for the
1997 annual PM2.5 NAAQS, establishing a December 31, 2023 attainment date. On May 23,
2024, the State of California transmitted a letter to the EPA requesting that the EPA grant a one-

Id. at 58070.
See Delaware Dept. of Nat. Resources and Envtl. Control v. EPA, 895 F.3d 90, 101 (D.C. Cir. 2018) (holding that
for the purposes of an attainment date extension, the CAA requires only that an applying state with jurisdiction over
a nonattainment area comply with the requirements in its applicable SIP, not every requirement of the Act); see also
Vigil v. Leavitt, 381 F.3d 826, 846 (9th Cir. 2004). A state may meet this requirement by certifying its compliance,
and in the absence of such certification, the EPA may make a determination as to whether the criterion has been met.
See Delaware, 895 F.3d, pp. 101–102.
42 81 FR 58010, 58071.
40
year extension under CAA section 172(a)(2)(C) to the applicable Serious area attainment date for
the San Joaquin Valley from December 31, 2023, to December 31, 2024.43 In its request, the
State certified that it has complied with all requirements and commitments pertaining to the area
in the approved implementation plan and that complete, certified monitoring data for the San
Joaquin Valley for 2023 are below the level of the 1997 annual PM2.5 NAAQS.
The State’s May 23, 2024 extension request includes documentation in three enclosures
in support of its certification that it has complied with the requirements for an attainment date
extension under CAA section 172(a)(2)(C):
(1) A letter dated May 14, 2024, from Samir Sheikh, Executive Director/Air Pollution
Control Officer, SJVUAPCD, to Dr. Steven S. Cliff, Executive Officer, CARB,
Subject: “RE: Attainment Date Extension for the 1997 Annual PM2.5 Standard for the
San Joaquin Valley Nonattainment Area;”
(2) A document titled “Documentation of CARB Having Met Previous State
Implementation Plan Obligations for the 15 µg/m3 PM2.5 Standard for the San Joaquin
Valley” (“2024 CARB Compliance Demonstration”); and
(3) A letter dated April 29, 2024, from Sylvia Vanderspek, Chief, Air Quality Planning
Branch, CARB, to Dena Vallano, Manager, Monitoring and Analysis Section, EPA
Region 9, with enclosures, certifying 2023 ambient data collected by State and Local
Air Monitoring Stations and Special Purpose Monitors operated by CARB in the San
Joaquin Valley.
We briefly describe each of these documents in the remainder of this section and provide more
detail as part of our evaluation in Section III.
The District’s May 14, 2024 extension request letter includes a discussion of the State’s
SIP submittals to address CAA requirements, including the control measure requirements under

Letter dated May 23, 2024, from Steven S. Cliff, Executive Officer, CARB, to Martha Guzman, Regional
Administrator, EPA Region 9, with enclosures.
CAA sections 189(b) and 189(d); the State’s submission of quantitative milestone reports
documenting its progress towards attaining the 1997 annual PM2.5 NAAQS; and the District’s
amendments to Rule 4901 (“Wood Burning Fireplaces and Wood Burning Heaters”) to address
contingency measure requirements and achieve reductions in PM2.5 emissions for purposes of
meeting the NAAQS. The District’s letter also presents certified ambient air monitoring data for
the San Joaquin Valley for the 2023 calendar year, which show that the annual mean
concentration was less than 15.0 µg/m3 (i.e., the level of the 1997 annual PM2.5 NAAQS) at all
monitoring sites.
The 2024 CARB Compliance Demonstration documents how CARB has complied with
all requirements and commitments pertaining to the San Joaquin Valley for the 1997 annual
PM2.5 NAAQS by addressing the requirements in each of the SIP submittals for those NAAQS
(i.e., the 2008 PM2.5 Plan, the 2015 PM2.5 Plan, the 2018 PM2.5 Plan, and the 15 µg/m3 SIP
Revision). For each attainment plan submittal, CARB discusses the control measure and
emissions reductions it committed to in the plan and the actions the State has taken to meet those
commitments (i.e., by adopting the measures identified in the plan or by adopting substitute
measures). CARB also discusses the measures the State has adopted and submitted to the EPA to
address contingency measure requirements and submissions it has made to meet its obligations to
submit quantitative milestone reports for the 1997 annual PM2.5 NAAQS.
Lastly, in support of the State’s assertion that it has met the air quality criterion for a oneyear attainment date extension for the 1997 annual PM2.5 NAAQS, CARB included with its
extension request a letter certifying 2023 ambient data for the San Joaquin Valley collected by
monitors operated by CARB.
III. The EPA’s Evaluation
A. Compliance with the Applicable SIP
The first requirement for an extension of the attainment date under CAA section
172(a)(2)(C) is a showing that the state has complied with all requirements and commitments

pertaining to that area in the implementation plan. As discussed in Section I.C of this document,
the EPA interprets this requirement to mean that a state must have adopted and be implementing
the control measures and commitments in the SIP revisions it has submitted to address the CAA
requirements for the applicable PM2.5 NAAQS. For the San Joaquin Valley for the 1997 annual
PM2.5 NAAQS, the EPA has approved control measure requirements and commitments in the
2008 PM2.5 Plan and the 15 µg/m3 SIP Revision to the 2018 PM2.5 Plan into the California SIP.
Therefore, in the remainder of this section, we describe the State’s and District’s implementation
of the control measures and commitments in those plans.
1. 2008 PM2.5 Plan
The specific State and District commitments that the EPA approved into the California
SIP as part of the 2008 PM2.5 Plan are as follows:
(1) A commitment by CARB to propose specific measures identified in Appendix B of
the “Progress Report on Implementation of PM2.5 State Implementation Plans (SIP)
for the South Coast and San Joaquin Valley Air Basins and Proposed SIP Revisions,”
dated April 28, 2011 (“2011 Progress Report”), in accordance with the timetable
specified therein;44
(2) A commitment by the District to “adopt and implement the rules and measures in the
2008 PM2.5 Plan” in accordance with the timetable specified in Table 6–2 of the 2008
PM2.5 Plan, as amended June 17, 2010, and to submit these rules and measures to
CARB for transmittal to the EPA as SIP revisions;45
(3) A commitment by CARB to achieve a total of 17.1 tons per day (tpd) of NOX
emissions reductions and 2.3 tpd of direct PM2.5 emissions reductions by 2014 as
described in CARB Resolution No. 07–28, Attachment B, as amended in 2009 and

40 CFR 52.220(c)(395)(ii)(A)(2), CARB Resolution No. 07–28, Attachment B (September 27, 2007), CARB
Resolution No. 09–34 (April 24, 2009), and CARB Resolution No. 11–24 (April 28, 2011); see also 76 FR 69896,
69921–69922, Table 2.
45 40 CFR 52.220(c)(392)(ii)(A)(2), SJVUAPCD Governing Board Resolution No. 08–04–10 (April 30, 2008), and
SJVUAPCD Governing Board Resolution No. 10–06–18 (June 17, 2010); see also 76 FR 69896 at 69921, Table 1.
2011;46 and
(4) A commitment by the District to achieve a total of 8.97 tpd of NOX emissions
reductions and 0.92 tpd of SOX emissions reductions by 2014, as described in Table
6–3a, Table 6–3b, and Table 6–3c, respectively, of the 2008 PM2.5 Plan.47
As of November 9, 2011, the date of the EPA’s final action on the 2008 PM2.5 Plan,
CARB and the District had each satisfied substantial portions of these control measure and
emissions reduction commitments. Specifically, CARB had proposed action on six of the seven
measures it had committed to propose for Board consideration, leaving one additional measure
that was scheduled for proposal in 2013 (“New Emissions Standards for Recreational Boats”).48
The District had adopted 12 of the 13 measures it had committed to adopt and implement,
leaving one additional measure that was scheduled for adoption in 2014, amendments to Rule
4905 (“National Gas-Fired, Fan-Type Central Furnaces”).49 Finally, together CARB and the
District had achieved all of the SOX emissions reduction commitments and substantial portions
of the direct PM2.5 and NOX emissions reductions commitments through implementation of State
and District control strategy measures, leaving 3.0 tpd of direct PM2.5 emissions reductions and
12.9 tpd of NOX emissions reductions yet to be achieved by the beginning of 2014.50
Subsequently, CARB submitted a staff report, entitled “Review of San Joaquin Valley
PM2.5 State Implementation Plan” (“2015 CARB Compliance Demonstration”), that contains
CARB’s demonstration that both CARB and the District had satisfied the commitments in the
2008 PM2.5 Plan that remained outstanding as of November 9, 2011.51 As discussed in the 2015
CARB Compliance Demonstration, on January 22, 2015, the District adopted amendments to
40 CFR 52.220(c)(356)(ii)(B)(2).
40 CFR 52.220(c)(392)(ii)(A)(2).
48 76 FR 69896, 69922, Table 2 (“2007 State Strategy Defined Measures Schedule for Consideration and Current
Status”).
49 Id. at 69921, Table 1 (“San Joaquin Valley Air Pollution Control District 2008 PM
2.5 Plan Specific Rule
Commitments”).
50 Id. at 69923, Table 4 (“Reductions Needed for Attainment Remaining as Commitments Based on SIP-Creditable
Measures”).
51 CARB, “Review of San Joaquin Valley PM
2.5 State Implementation Plan,” released April 20, 2015 (“2015 CARB
Compliance Demonstration”), transmitted by email dated February 5, 2020, from Michael Benjamin, CARB to
Meredith Kurpius, EPA Region IX, pp. 17–22 and Appendix B.
46
Rule 4905 and on April 7, 2015, CARB submitted this rule to the EPA as a revision to the
California SIP.52 Second, on February 19, 2015, CARB proposed for Board consideration, and
the Board adopted, new emissions standards for recreational boats entitled “Evaporative
Emissions Control Requirements for Spark-Ignition Marine Watercraft.”53 These State and
District rulemaking actions satisfied the last remaining control measure commitments in the 2008
PM2.5 Plan. All of these measures have been submitted to the EPA and approved into the
California SIP.54
With respect to the remaining emissions reduction commitments, the 2015 CARB
Compliance Demonstration, as amended by CARB’s “Technical Clarifications to the 2015 San
Joaquin Valley PM2.5 State Implementation Plan,” identified State and District control measures
that, according to CARB, achieved emissions reductions beyond those already credited towards
the 2008 PM2.5 Plan and satisfied the State’s remaining 2014 emissions reduction obligations.55
The EPA previously determined that the State and District measures identified in the State’s
demonstration achieved a total of 12.97 tpd of NOX emissions reductions and 3.0 tpd of direct
PM2.5 emissions reductions. These reductions had not previously been credited as part of the
attainment demonstration in the 2008 PM2.5 Plan and therefore could be credited toward the
State’s outstanding obligation to achieve 12.9 tpd of NOX emissions reductions and 3.0 tpd of
direct PM2.5 emissions reductions by the beginning of 2014.56 Therefore, we concluded that the
State had complied with all requirements and commitments pertaining to the San Joaquin Valley

2015 CARB Compliance Demonstration, p. 19, Table 7, and letter dated April 7, 2015, from Richard Corey,
Executive Officer, CARB, to Jared Blumenfeld, Regional Administrator, EPA Region 9 (transmitting air district
regulations to the EPA as California SIP revisions).
53 2015 CARB Compliance Demonstration, p. 20, Table 8 and CARB, Resolution 15–3, “Evaporative Emissions
Control Requirements for Spark-Ignition Marine Watercraft,” February 19, 2015, available at
https://www.arb.ca.gov/regact/2015/simw2015/simw2015.htm.
54 See Technical Support Document, EPA General Evaluation, San Joaquin Valley PM
2.5 Plan for the 2006 PM2.5
NAAQS, Table III-A.
55 2015 CARB Compliance Demonstration, pp. 21–22, and CARB, “Technical Clarifications to the 2015 San
Joaquin Valley PM2.5 State Implementation Plan,” transmitted by email dated February 5, 2020, from Michael
Benjamin, CARB to Meredith Kurpius, EPA Region IX, pp. 1–4.
56 85 FR 44192 (July 22, 2020). Also see the EPA’s proposed rulemaking at 85 FR 17382, 17405–17407 (March 27,
2020).
nonattainment area in the implementation plan for the 1997 PM2.5 NAAQS.57
2. 15 µg/m3 SIP Revision
The control strategy in the 15 µg/m3 SIP Revision was based primarily on ongoing
emissions reductions from baseline control measures (i.e., State and District regulations adopted
prior to the development of the plan that continue to achieve emissions reductions through the
projected attainment year and beyond).58 However, the 15 µg/m3 SIP Revision also identified
several additional control measures to provide for expeditious attainment of the 1997 annual
PM2.5 NAAQS.59 These measures include three regulatory measures adopted by CARB or the
District following development of the 2018 PM2.5 Plan and a commitment by CARB to adopt
and implement an additional regulatory measure to meet an enforceable commitment.
The three regulatory measures adopted following development of the 2018 PM2.5 Plan
include CARB’s “Lower Opacity Limits for Heavy-Duty Vehicles” regulation,60 CARB’s
“Amended Warranty Requirements for Heavy-Duty Vehicles” regulation,61 and the District’s
2019 amendments to Rule 4901 (“Wood Burning Fireplaces and Wood Burning Heaters”).62 As
discussed in our July 14, 2023 proposal to approve the 15 µg/m3 SIP Revision, all three of these
measures have been adopted by the State and submitted to the EPA for SIP approval.63 The EPA
approved the District’s 2019 amendments to Rule 4901 on July 22, 2020,64 and as part of our
final rule approving the 15 µg/m3 SIP Revision, we credited this measure with annual average
emissions reductions of 0.2 tpd of direct PM2.5 for the purpose of attaining the 1997 annual PM2.5

Id.
These baseline control measures include many EPA-approved regulations for on-road and non-road mobile
sources, as well as District measures that limit NOX and PM2.5 emissions from stationary and area sources. See
discussion in the EPA’s July 14, 2023, proposed approval of the plan (88 FR 45276, 45297–45299).
59 Id. at 45299–45300.
60 Initially adopted via CARB Resolution 18-20 (May 25, 2018). CARB Resolution 18-20 was repealed on July 26,
2018 via CARB Resolution 18-28, which included a modified version of the regulation to address public comments.
Per direction from CARB Resolution 18-28, the regulation was adopted via Executive Order R19-001 (March 12,
2019).
61 CARB Resolution 18-24, June 28, 2018.
62 SJVUAPCD Resolution 19-06-22, June 20, 2019.
63 88 FR 45276, 45299–45300.
64 85 FR 44206.
57
NAAQS by December 31, 2023.65 The EPA did not credit CARB’s Lower Opacity Limits for
Heavy-Duty Vehicles regulation or the Amended Warranty Requirements for Heavy-Duty
Vehicles regulation with any particular amount of emissions reductions toward attainment of the
1997 annual PM2.5 NAAQS for the reasons discussed in our proposal; however, we noted that the
relatively small quantity of emissions reductions from these measures would not materially affect
the attainment demonstration for the 1997 annual PM2.5 NAAQS.66
CARB’s commitment in the 15 µg/m3 SIP Revision was to achieve aggregate emissions
reductions of 3.0 tpd of NOX and 0.04 tpd of direct PM2.5 (referred to as an “aggregate tonnage
commitment”) through adoption of CARB’s “Heavy-Duty Vehicle Inspection and Maintenance
Program” (“Heavy-Duty I/M”) (referred to as a “control measure commitment”) and/or
substitute measures.67 CARB adopted the Heavy-Duty I/M measure on December 9, 2021,
fulfilling CARB’s control measure commitment in the 15 µg/m3 SIP Revision. On December 14,
2022, CARB submitted the measure to the EPA as a revision to the California SIP.68,69
Implementation of the program began on January 1, 2023.
In addition to the baseline and additional measures discussed herein, CARB noted in its
“Staff Report, Proposed SIP Revision for the 15 ug/m3 Annual PM2.5 Standard for the San
Joaquin Valley,” (“August 2021 Staff Report”) accompanying the 15 µg/m3 SIP Revision that
the “Accelerated Turnover of Agricultural Equipment Incentive Projects” (“Valley Incentive
Measure”) was expected to provide for further emissions reductions by the 2023 attainment
year.70 The Valley Incentive Measure includes commitments by CARB to monitor, assess, and
report on emissions reductions, and to achieve emissions reductions of 5.1 tpd of NOX and 0.3

88 FR 86581. See also the discussion regarding this measure in our July 14, 2023, proposed approval (88 FR
45276, 45299).
66 88 FR, 45276, 45300.
67 CARB Resolution 21-21, September 23, 2021, p. 6; and August 2021 Staff Report, pp. 4–5.
68 Letter dated December 7, 2022, from Steven S. Cliff, Ph.D., Executive Officer, to Martha Guzman, Regional
Administrator, EPA Region IX, with enclosures.
69 At the time that this document was being prepared, the EPA had not yet proposed action on the Heavy-Duty I/M
measure.
70 August 2021 Staff Report, pp. 3–4.
tpd of direct PM2.5 from the 2025 baseline inventory in the 2018 PM2.5 Plan by December 31,
2024.71 The EPA finalized a partial approval of this measure on December 16, 2021, wherein the
EPA credited 4.83 tpd of NOX and 0.24 tpd of direct PM2.5 towards CARB’s tonnage
commitments for 2024 (for attaining the 2006 24-hour PM2.5 NAAQS).72 While the State did not
take credit for any emissions reductions from this measure in the 15 µg/m3 SIP Revision, it
asserted in the August 2021 Staff Report that a large portion of those emissions reductions would
in fact be achieved by 2023.73
To address how California has met the outstanding aggregate tonnage commitment in the
15 µg/m3 SIP Revision, CARB provided updates on implementation of the Heavy-Duty I/M
program and the Valley Incentive Measure in the 2024 CARB Compliance Demonstration. For
the Heavy-Duty I/M program, CARB provided a summary of the vehicle screening, inspections,
and citations issued in San Joaquin Valley cities in 2023.74 CARB notes that these enforcement
efforts led to a reduction in emissions from heavy-duty vehicles in the San Joaquin Valley.
However, CARB explains that because of the “time-sensitive nature of documenting that we
achieved the CARB emission reduction commitment,” it is relying on the reductions achieved by
a substitute measure, the Valley Incentive Measure, to demonstrate that it has met the aggregate
tonnage commitment in the 15 µg/m3 SIP Revision.
On June 21, 2024, CARB submitted the “Amendments to the 15 µg/m3 SIP Revision and
Agricultural Equipment Incentive Measure for the 1997 PM2.5 Standard” (“15 µg/m3 Plan
Amendments”) for parallel processing.75 The 15 µg/m3 Plan Amendments revises the State’s

EPA Region IX “Technical Support Document for EPA’s Rulemaking for the California State Implementation
Plan California Air Resources Board Resolution 19–26 San Joaquin Valley Agricultural Equipment Incentive
Measure,” February 2020, pp. 4–5, 24–25, and 31.
72 86 FR 73106 (December 27, 2021). The EPA approved the Carl Moyer Memorial Air Quality Standards
Attainment Program (“Carl Moyer Program”) and Funding Agricultural Replacement Measures for Emission
Reductions Program” (“FARMER Program”). The EPA deferred action on the United States Department of
Agriculture’s Natural Resources Conservation Service (NRCS) Environmental Quality Incentive Program (EQIP)
portion of the Valley Incentive Measure.
73 CARB's August 2021 Staff Report, p. 3.
74 2024 CARB Compliance Demonstration, pp. 7–8.
75 Letter dated June 21, 2024, from Steven S. Cliff, Ph.D., Executive Officer, CARB, to Martha Guzman, Regional
Administrator, EPA Region 9, with enclosure.
aggregate tonnage commitment in the 15 µg/m3 SIP Revision, amends the Valley Incentive
Measure, and demonstrates that projects implemented under the SIP-approved Valley Incentive
Measure achieved specified amounts of reductions in emissions of NOX and PM2.5 in the San
Joaquin Valley area in the year 2023. In a separate current action, the EPA is proposing to
approve the 15 µg/m3 Plan Amendments, credit the emissions reductions of 5.0 tpd of NOX and
0.27 tpd of direct PM2.5 from the Valley Incentive Measure in the year 2023, and formally
substitute the Valley Incentive Measure for the Heavy-Duty I/M measure as the measure
satisfying the aggregate tonnage commitment for the 15 µg/m3 SIP Revision.76 In this action, the
EPA is proposing to find that, upon final approval of the 15 µg/m3 Plan Amendments, the State
will have adequately documented that it has complied with its commitment to achieve 3.0 tpd of
NOX and 0.04 tpd of direct PM2.5 emissions reductions by the beginning of 2023. Thus, based on
the EPA’s review of the requirements and commitments pertaining to the San Joaquin Valley in
the 2008 PM2.5 Plan and 15 µg/m3 SIP Revision, the supporting information in the State’s
extension request, and additional information discussed herein, we find that the State has
complied with all requirements for the 1997 annual PM2.5 NAAQS in the applicable SIP. We
therefore propose to find that the area meets the first criterion to qualify for a one-year
attainment date extension under CAA section 172(a)(2)(C).
B. Air Quality Data
As discussed in Section I.C of this document, the second requirement for an extension of
the attainment date under CAA section 172(a)(2)(C) is a showing that the area had clean data for
the relevant standard in the calendar year preceding the applicable attainment date. Such
determination is typically based upon complete, quality-assured data gathered at established
State and Local Air Monitoring Stations (SLAMS) in a nonattainment area and entered into the
EPA’s Air Quality System (AQS) database. Data from ambient air monitors operated by
state/local agencies in compliance with the EPA monitoring requirements must be submitted to

The EPA is proposing to approve the 15 µg/m3 Plan Amendments in a separate rulemaking.

AQS. Monitoring agencies annually certify that these data are accurate to the best of their
knowledge. Accordingly, the EPA relies primarily on data in AQS when determining compliance
with the NAAQS.77 The EPA reviews all data to determine the area’s air quality status in
accordance with 40 CFR part 50, Appendix N. Under EPA regulations in 40 CFR 50.7 and in
accordance with Appendix N, the 1997 annual PM2.5 NAAQS are met when the annual
arithmetic mean concentration, as determined in accordance with the rounding conventions in 40
CFR part 50, Appendix N, is less than or equal to 15.0 µg/m3 at each eligible monitoring site
within the area. 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.78
Section 110(a)(2)(B)(i) of the CAA requires states to establish and operate air monitoring
networks to compile data on ambient air quality for all criteria pollutants. The monitoring
requirements are specified in 40 CFR part 58. These requirements are applicable to state, and
where delegated, local air monitoring agencies that operate criteria pollutant monitors. The
regulations in 40 CFR part 58 establish specific requirements for operating air quality
surveillance networks to measure ambient concentrations of PM2.5, including requirements for
measurement methods, network design, quality assurance procedures, and, in the case of large
urban areas, the minimum number of monitoring sites designated as SLAMS.
In section 4.7 of Appendix D to 40 CFR part 58, the EPA specifies minimum monitoring
requirements for PM2.5 to operate at SLAMS. SLAMS produce data comparable to the NAAQS,
and therefore, the monitor must be an approved federal reference method (FRM) or federal
equivalent method (FEM). The minimum number of SLAMS required is described in section
4.7.1 and can be met by either filter-based or continuous FRMs or FEMs. The monitoring
regulations also provide that each core-based statistical area must operate a minimum number of

See 40 CFR 50.7; 40 CFR part 50, Appendix L; 40 CFR part 53; 40 CFR part 58, and 40 CFR part 58, appendices
A, C, D, and E.
78 40 CFR part 50, Appendix N, section 4.1(b).
PM2.5 continuous monitors;79 however, this requirement can be met by either an FEM or a nonFEM continuous monitor, and the continuous monitors can be located with other SLAMS or at a
different location. Consequently, the monitoring requirements for PM2.5 can be met with filterbased FRMs/FEMs, continuous FEMs, continuous non-FEMs, or a combination of monitors at
each required SLAMS.
During 2023, ambient PM2.5 concentration data were collected at a total of 18 sites within
the San Joaquin Valley: 5 sites in Fresno County; 3 sites in Kern County; 2 sites each in Kings,
Merced, San Joaquin, and Stanislaus counties; and 1 site each in Madera and Tulare counties.
The District operates 12 of these sites while CARB operates 6 of these sites. All of the sites are
designated SLAMS for PM2.5.80 The primary monitors are FRMs at 1 of the 18 sites and beta
attenuation monitor FEMs at 17 of the 18 sites. Overall, the District’s PM2.5 monitoring network
meets, and in several metropolitan statistical areas exceeds, the PM2.5 minimum monitoring
requirements for the San Joaquin Valley.
Based on our review of the PM2.5 monitoring network as summarized above, we find that
the monitoring network in the San Joaquin Valley is adequate for the purpose of collecting
ambient PM2.5 concentration data for use in determining whether the San Joaquin Valley had
clean data for the 1997 annual PM2.5 NAAQS during the 2023 calendar year.
Under 40 CFR 58.10, states are required to submit annual monitoring network plans to
the EPA.81 Within the San Joaquin Valley, CARB and the District are the agencies responsible
for assuring that the area meets air quality monitoring requirements. CARB and SJVUAPCD
submit monitoring network plans to the EPA annually. These plans describe and discuss the
status of the air monitoring network, as required under 40 CFR 58.10. The EPA reviews these
annual network plans for compliance with the applicable reporting requirements in 40 CFR part

40 CFR part 58, Appendix D, section 4.7.2.
There are a number of other PM2.5 monitoring sites within the valley, including other sites operated by the
District, the National Park Service, and certain Indian tribes, but the data collected from these sites are nonregulatory and not eligible for comparison with the PM2.5 NAAQS.
81 40 CFR 58.10(a)(1).
79
58. With respect to PM2.5, we have found that the CARB and SJVUAPCD annual network plans
meet the applicable requirements under 40 CFR part 58.82
Under 40 CFR 58.15, monitoring agencies must certify, on an annual basis, that data
collected at all SLAMS and at all FRM and FEM special purpose monitor stations meet the
EPA’s quality assurance requirements. In doing so, monitoring agencies must certify that the
previous year of ambient concentration and quality assurance data are submitted to AQS and that
the ambient concentration data are accurate. CARB annually certifies that the data the agency
submits to AQS are quality assured, including the data collected at monitoring sites in the San
Joaquin Valley.83 SJVUAPCD does the same for data submitted to AQS from monitoring sites
operated by the District.84
With respect to data completeness, we determined that the data collected by CARB and
the District meet the quarterly completeness criterion for all four quarters of 2023 at most of the
PM2.5 monitoring sites in the San Joaquin Valley. More specifically, among the 18 PM2.5
monitoring sites from which regulatory data are available, only the data from StocktonUniversity (AQS ID: 06-077-1003) did not meet the 75 percent completeness criterion for one
quarter;85 however, the data from the site are sufficient nonetheless to produce a valid design
value for the 1997 annual PM2.5 NAAQS pursuant to the rules governing design value validity in
40 CFR part 50, Appendix N, section 4.1.
The EPA evaluated data from calendar year 2023 to determine whether the San Joaquin
Valley PM2.5 nonattainment area met the air quality criterion for granting a one-year extension of

Letter dated October 30, 2023, from Dena Vallano, Manager, Monitoring and Analysis Section, EPA Region IX,
to Sylvia Vanderspek, Manager, Air Quality Planning Branch, CARB; and letter dated October 31, 2023, from Dena
Vallano, Manager, Monitoring and Analysis Section, EPA Region IX, to Jon Klassen, Director, Air Quality Science,
SJVUAPCD.
83 For example, see letter dated April 29, 2024, from Sylvia Vanderspek, Chief, Air Quality Planning Branch,
CARB, to Dena Vallano, Manager, Monitoring and Analysis Section, EPA Region 9, with enclosures, certifying
calendar year 2023 ambient air quality data and quality assurance data.
84 For example, see letter dated April 23, 2024, from Robert Gilles, Program Manager, SJVUAPCD, to Matt Lakin,
Director, Air and Radiation Division, EPA Region IX, with attachments, certifying calendar year 2023 ambient air
quality data and quality assurance data.
85 EPA AQS Combined Site Sample Values, AMP355, accessed May 17, 2024 (User ID: STSAI, Report Request
ID: 2193827).
the applicable attainment date for the 1997 annual PM2.5 NAAQS from December 31, 2023, to
December 31, 2024, under CAA section 172(a)(2)(C). Table 1 shows the PM2.5 annual mean at
each of the 18 SLAMS monitoring sites for 2023.
Table 1 – 2023 PM2.5 Annual Mean for the San Joaquin Valley Nonattainment Area
Annual Mean
County
Site Name
Site (AQS ID)
(µg/m3)
Fresno
Fresno-Garland
06-019-0011
10.5
Fresno
Tranquillity
06-019-2009
4.8
Fresno
Fresno-Foundry
06-019-2016
12.5
Fresno
Clovis-Villa
06-019-5001
8.6
Fresno
Fresno-Pacific
06-019-5025
12.6
Kern
Bakersfield-Golden/M-St
06-029-0010
13.7
Kern
Bakersfield-California
06-029-0014
12.0
Kern
Bakersfield-Airport (Planz)
06-029-0016
12.5
Kings
Corcoran-Patterson
06-031-0004
10.1
Kings
Hanford-Irwin
06-031-1004
12.5
Merced
Merced-M St
06-047-2510
9.6
Merced
Merced-Coffee
06-047-0003
8.4
San Joaquin
Stockton - University Park
06-077-1003
10.8a
San Joaquin
Manteca
06-077-2010
7.9
Stanislaus
Modesto-14th Street
06-099-0005
10.5
Stanislaus
Turlock
06-099-0006
10.1
Madera
Madera-City
06-039-2010
9.9
Tulare
Visalia-W. Ashland Avenue
06-107-2003
11.7
Quarter 2 does not meet completeness criteria.
Source: EPA AQS Design Value Report, AMP480, accessed May 17, 2024 (User ID: STSAI, Report Request ID:
2193813).
a

Table 1 shows that the annual mean for the 2023 calendar year was less than 15.0 µg/m3
(i.e., the level of the 1997 annual PM2.5 NAAQS) at each of the 18 SLAMS monitoring sites in
the San Joaquin Valley. Thus, the EPA proposes to find that the area meets the air quality
criterion to qualify for a one-year attainment date extension under CAA section 172(a)(2)(C).
IV. Environmental Justice Considerations
Executive Order 12898 requires that federal agencies, to the greatest extent practicable
and permitted by law, identify and address disproportionately high and adverse human health or
environmental effects of their actions on minority and low-income populations.86 Additionally,
Executive Order 13985 directs federal government agencies to assess whether, and to what

59 FR 7629 (February 16, 1994).

extent, their programs and policies perpetuate systemic barriers to opportunities and benefits for
people of color and other underserved groups,87 and Executive Order 14008 directs federal
agencies to develop programs, policies, and activities to address the disproportionate health,
environmental, economic, and climate impacts on disadvantaged communities.88
The CAA gives the EPA the discretion to extend an area’s applicable attainment date by
one year upon application by a state if the state has met the two criteria under CAA section
172(a)(2)(C) (see Section I.C of this document). To identify environmental burdens and
susceptible populations in underserved communities in the San Joaquin Valley nonattainment
area and to better understand the context of our proposed action on these communities, we rely
on the EPA’s August 2022 screening-level analysis for PM2.5 in the San Joaquin Valley using the
EPA’s environmental justice (EJ) screening and mapping tool (“EJSCREEN”).89,90 The results of
this analysis are being provided for informational and transparency purposes.
Our screening-level analysis indicates that the “Demographic Index” for each of the eight
counties in the San Joaquin Valley is above the national average, ranging from 48 percent in
Stanislaus County to 61 percent in Tulare County, compared to 36 percent nationally. The
Demographic Index is the average of an area’s percent minority and percent low-income
populations, i.e., the two populations explicitly named in Executive Order 12898.91 All eight

86 FR 7009 (January 25, 2021).
86 FR 7619 (February 1, 2021).
89 EJSCREEN provides a nationally consistent dataset and approach for combining environmental and demographic
indicators. EJSCREEN is available at https://www.epa.gov/ejscreen/what-ejscreen. The EPA used EJSCREEN to
obtain environmental and demographic indicators representing each of the eight counties in the San Joaquin Valley.
We note that the indicators for Kern County are for the entire county. While the indicators might have slightly
different numbers for the San Joaquin Valley portion of the county, most of the county’s population is in the San
Joaquin Valley portion, and thus the differences would be small. These indicators are included in EJSCREEN
reports that are available in the rulemaking docket for this action.
90 EPA Region IX, “EJSCREEN Analysis for the Eight Counties of the San Joaquin Valley Nonattainment Area,”
August 2022.
91 EJSCREEN reports environmental indicators (e.g., air toxics cancer risk, Pb paint exposure, and traffic proximity
and volume) and demographic indicators (e.g., people of color, low income, and linguistically isolated populations).
The value for a particular indicator measures how the community of interest compares with the state, the EPA
region, or the national average. For example, if a given location is at the 95th percentile nationwide, this means that
only 5 percent of the U.S. population has a higher value than the average person in the location being analyzed.
EJSCREEN also reports EJ indexes, which are combinations of a single environmental indicator with the
EJSCREEN Demographic Index. For additional information about environmental and demographic indicators and
EJ indexes reported by EJSCREEN, see EPA, “EJSCREEN Environmental Justice Mapping and Screening Tool –
EJSCREEN Technical Documentation,” Section 2 (September 2019).
87
counties are above the national average for demographic indices of “Linguistically Isolated
Population” and “Population with Less than High School Education.”
With respect to pollution, all eight counties are at or above the 97th percentile nationally
for the PM2.5 index and seven of the eight counties in the San Joaquin Valley are at or above the
90th percentile nationally for the PM2.5 EJ index, which is a combination of the Demographic
Index and the PM2.5 index. Most counties are also above the 80th percentile for each of 11
additional EJ indices included in the EPA’s EJSCREEN analysis. In addition, several counties
are above the 90th percentile for certain EJ indices, including, for example, the Ozone EJ Index
(Fresno, Kern, Madera, Merced, and Tulare counties), the National Air Toxics Assessment
(NATA) Respiratory Hazard EJ Index (Madera and Tulare counties), and the Wastewater
Discharge Indicator EJ Index (Merced, San Joaquin, Stanislaus, and Tulare counties).92
This proposed action would grant an extension of attainment date for the 1997 annual
PM2.5 NAAQS. Information on the 1997 annual PM2.5 NAAQS and its relationship to negative
health impacts can be found at 62 FR 38652 (July 18, 1997). We expect that this action will
generally have neutral environmental and health impacts on all populations in the San Joaquin
Valley, including people of color and low-income populations. This action would not worsen
existing air quality and there is no information in the record indicating that this action is expected
to have disproportionately high or adverse human health or environmental effects on a particular
group of people.
V.

The EPA’s Proposed Action
In response to a request from the State of California on May 23, 2024, the EPA is

proposing to grant a one-year extension to the applicable Serious area attainment date for the
1997 annual PM2.5 NAAQS for the San Joaquin Valley nonattainment area. The proposed action
to extend the applicable Serious attainment date for this nonattainment area is based on the

Notably, Tulare County is above the 90th percentile for 6 of the 12 EJ indices in the EPA’s EJSCREEN analysis,
including the PM2.5 EJ Index, which is the highest value among all San Joaquin Valley counties.
EPA’s evaluation of air quality monitoring data and the extension request submitted by the State
of California and our determination that the State has satisfied the two statutory criteria for a 1year extension under CAA section 172(a)(2)(C).
If finalized, this action would extend the applicable Serious area attainment date for the
San Joaquin Valley nonattainment area from December 31, 2023, to December 31, 2024. If we
finalize this proposal, consistent with CAA section 172(a)(2)(C), the area will remain a Serious
PM2.5 nonattainment area with an applicable Serious area attainment date of December 31, 2024.
Consistent with CAA section 172(a)(2)(C), the EPA will determine whether the area attained the
standard within six months following the applicable attainment date.
VI. 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 merely proposes to approve a
state request as meeting federal requirements and imposes no new requirements.
B. Paperwork Reduction Act (PRA)
This action does not impose an information collection burden under the PRA. This action
merely proposes to approve a state request for an attainment date extension, and this action does
not impose additional requirements beyond those imposed by state law.
C. 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. Approval of a state’s request for an attainment date
extension does not create any new requirements and does not directly regulate any entities.

D. 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.
E. 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 merely proposes to approve a state request for an attainment date
extension.
F. 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 it will not
impose substantial direct costs on tribal governments or preempt tribal law. Thus, Executive
Order 13175 does not apply to this action.
G. 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 2202 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.
H. 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.
I. 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.
J. Executive Order 12898: Federal Actions to Address Environmental Justice in Minority
Populations and Low-Income Population
Executive Order 12898 (Federal Actions To Address Environmental Justice in Minority
Populations and Low-Income Populations, 59 FR 7629, February 16, 1994) directs Federal
agencies to identify and address “disproportionately high and adverse human health or
environmental effects” of their actions on minority populations and low-income populations to
the greatest extent practicable and permitted by law. The EPA defines EJ as “the fair treatment
and meaningful involvement of all people regardless of race, color, national origin, or income
with respect to the development, implementation, and enforcement of environmental laws,
regulations, and policies.” The EPA further defines the term fair treatment to mean that “no
group of people should bear a disproportionate burden of environmental harms and risks,
including those resulting from the negative environmental consequences of industrial,
governmental, and commercial operations or programs and policies.”
Under the CAA, an extension of the attainment date under section 172(a)(2)(C) does not
impose any additional regulatory requirements on sources beyond those imposed by state law.
The State did not evaluate EJ considerations as part of its documentation supporting its request
for an attainment date extension; the CAA and applicable implementing regulations neither

prohibit nor require such an evaluation. The EPA performed an EJ analysis, as is described
above in the section titled, “Environmental Justice Considerations.” The analysis was included in
this document for the purpose of providing additional context and information about this
rulemaking to the public, not as a basis of the action. Due to the nature of the action being taken
here, this action is expected to have a neutral impact on the air quality of the affected area. In
addition, there is no information in the record upon which this decision is based inconsistent with
the stated goal of EO 12898 of achieving EJ for people of color, low-income populations, and
Indigenous peoples.
List of Subjects in 40 CFR Part 52
Environmental protection, Air pollution control, Ammonia, Incorporation by reference,
Intergovernmental relations, Nitrogen oxides, Ozone, Particulate matter, Reporting and
recordkeeping requirements, Sulfur oxides, Volatile organic compounds.

Dated: June 27, 2024.
Cheree Peterson,
Acting Regional Administrator, Region IX.

[FR Doc. 2024-14617 Filed: 7/5/2024 8:45 am; Publication Date: 7/8/2024]