[Federal Register Volume 86, Number 138 (Thursday, July 22, 2021)]
[Proposed Rules]
[Pages 38652-38674]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2021-15551]



[[Page 38652]]

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 52

[EPA-R09-OAR-2021-0260; FRL-8644-02-R9]


Partial Approval and Partial Disapproval of Air Quality 
Implementation Plans; California; San Joaquin Valley Serious Area and 
Section 189(d) Plan for Attainment of the 1997 Annual PM2.5 NAAQS

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.

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SUMMARY: The Environmental Protection Agency (EPA) is proposing to 
approve in part and disapprove in part portions of a state 
implementation plan (SIP) revision submitted by the State of California 
to meet Clean Air Act (CAA or ``Act'') requirements for the 1997 annual 
fine particulate matter (PM<INF>2.5</INF>) national ambient air quality 
standards (NAAQS or ``standards'') in the San Joaquin Valley 
PM<INF>2.5</INF> nonattainment area. Specifically, the EPA is proposing 
to approve the 2013 base year emissions inventories in the submitted 
SIP revisions. Because the area did not attain by the State's projected 
attainment date of December 31, 2020, the EPA is proposing to 
disapprove the attainment demonstration and related elements, including 
the comprehensive precursor demonstration, five percent annual emission 
reductions demonstration, best available control measures (BACM) 
demonstration, reasonable further progress (RFP) demonstration, 
quantitative milestone demonstration, and contingency measures. The EPA 
is also proposing to disapprove the motor vehicle emission budgets in 
the plan as not meeting the requirements of the CAA and EPA 
regulations.

DATES: Any comments on this proposal must be received by August 23, 
2021.

ADDRESSES: Submit your comments, identified by Docket ID No. EPA-R09-
OAR-2021-0260 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 (e.g., 
audio or video) 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 disabilities 
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, Air Planning Office 
(ARD-2), EPA Region IX, 75 Hawthorne Street, San Francisco, CA 94105, 
(415) 972-3877, or by email at <a href="/cdn-cgi/l/email-protection#a8cfdac9c0c9c586c9dbc0c4cdd1dae8cdd8c986cfc7de"><span class="__cf_email__" data-cfemail="ddbaafbcb5bcb0f3bcaeb5b1b8a4af9db8adbcf3bab2ab">[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. San Joaquin Valley PM<INF>2.5</INF> Designations, 
Classifications, and SIP Revisions
II. Summary and Completeness Review of the San Joaquin Valley PM2.5 
Plan
    A. 2018 PM<INF>2.5</INF> Plan
    B. Valley State SIP Strategy
    C. District Rule 4901
III. Clean Air Act Requirements for Serious PM2.5 Areas That Fail To 
Attain
IV. Review of the San Joaquin Valley PM2.5 Plan
    A. Emissions Inventories
    B. PM<INF>2.5</INF> Precursors
    C. Attainment Plan Control Strategy
    D. Attainment Demonstration and Modeling
    E. Reasonable Further Progress and Quantitative Milestones
    F. Contingency Measures
    G. Motor Vehicle Emission Budgets
    H. Nonattainment New Source Review Requirements Under CAA 
Section 189(e)
V. Proposed Action
    A. Effect of Finalizing the Proposed Disapproval Actions
VI. Statutory and Executive Order Reviews

I. Background for Proposed Action

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 they should be revised or whether new NAAQS should be 
established.
    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 (PM<INF>2.5</INF>).\1\ 
The EPA established primary and secondary annual and 24-hour standards 
for PM<INF>2.5</INF>.\2\ The annual primary and secondary standards 
were set at 15.0 micrograms per cubic meter ([mu]g/m\3\), based on a 
three-year average of annual mean PM<INF>2.5</INF> concentrations, and 
the 24-hour primary and secondary standards were set at 65 [mu]g/m\3\, 
based on the three-year average of the 98th percentile of 24-hour 
PM<INF>2.5</INF> concentrations at each monitoring site within an 
area.\3\ Collectively, we refer herein to the 1997 annual and 24-hour 
PM<INF>2.5</INF> NAAQS as the ``1997 PM<INF>2.5</INF> NAAQS'' or ``1997 
PM<INF>2.5</INF> standards.''
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    \1\ 62 FR 38652.
    \2\ 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.
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    On October 17, 2006, the EPA revised the level of the 24-hour 
PM<INF>2.5</INF> NAAQS to 35 [mu]g/m\3\,\4\ and on January 15, 2013, 
the EPA revised the level of the primary annual PM<INF>2.5</INF> NAAQS 
to 12.0 [mu]g/m\3\.\5\ Even though the EPA has lowered the 24-hour and 
annual PM<INF>2.5</INF> standards, the 1997 PM<INF>2.5</INF> standards 
remain in effect.
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    \4\ 71 FR 61144.
    \5\ 78 FR 3086.
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    The EPA established these standards 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, and new evidence for more subtle 
indicators of cardiovascular health. Individuals particularly sensitive 
to PM<INF>2.5</INF> exposure include

[[Page 38653]]

older adults, people with heart and lung disease, and children.\6\
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    \6\ 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.\7\
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    \7\ For example, see 72 FR 20586, 20589 (April 25, 2007).
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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 attaining or not attaining the NAAQS. Effective April 5, 
2005, the EPA established the initial air quality designations for the 
1997 annual and 24-hour PM<INF>2.5</INF> NAAQS, using air quality 
monitoring data for the three-year periods of 2001-2003 and 2002-
2004.\8\ The EPA designated the San Joaquin Valley as nonattainment for 
both the 1997 annual PM<INF>2.5</INF> NAAQS (15.0 [mu]g/m\3\) and the 
1997 24-hour PM<INF>2.5</INF> NAAQS (65 [mu]g/m\3\).\9\
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    \8\ 70 FR 944 (January 5, 2005).
    \9\ 40 CFR 81.305.
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    The San Joaquin Valley PM<INF>2.5</INF> 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.\10\ 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 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.
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    \10\ For a precise description of the geographic boundaries of 
the San Joaquin Valley nonattainment area, see 40 CFR 81.305.
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    Within three years of the effective date of designations, states 
with areas designated as nonattainment for the 1997 PM<INF>2.5</INF> 
NAAQS were required to submit SIP revisions that, among other things, 
provided for implementation of reasonably available control measures 
(RACM), RFP, attainment of the standards as expeditiously as 
practicable but no later than five years from the nonattainment 
designation (in this instance, no later than April 5, 2010) unless the 
state justified an attainment date extension of up to five years, and 
contingency measures.\11\
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    \11\ CAA sections 172(a)(2), 172(c)(1), 172(c)(2), and 
172(c)(9).
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    Between 2007 and 2011, California submitted six SIP revisions to 
address nonattainment area planning requirements for the 1997 
PM<INF>2.5</INF> NAAQS in the San Joaquin Valley,\12\ which we refer to 
collectively as the ``2008 PM<INF>2.5</INF> Plan.'' On November 9, 
2011, the EPA approved the portions of the 2008 PM<INF>2.5</INF> Plan, 
as revised in 2009 and 2011, that addressed attainment of the 1997 
PM<INF>2.5</INF> NAAQS in the San Joaquin Valley PM<INF>2.5</INF> 
nonattainment area, except for the attainment contingency measures, 
which we disapproved.\13\ We also granted the State's request to extend 
the attainment deadline for the 1997 PM<INF>2.5</INF> NAAQS in the San 
Joaquin Valley to April 5, 2015.\14\
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    \12\ 76 FR 69896, n. 2 (November 9, 2011).
    \13\ Id. at 69924.
    \14\ Id.
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    Following a January 4, 2013 decision of the U.S. Court of Appeals 
for the D.C. Circuit (``D.C. Circuit'') remanding the EPA's 2007 
implementation rule for the 1997 PM<INF>2.5</INF> NAAQS,\15\ the EPA 
published a final rule on June 2, 2014, classifying the San Joaquin 
Valley, among other areas, as a Moderate nonattainment area for the 
1997 PM<INF>2.5</INF> NAAQS under subpart 4, part D of title I of the 
Act.\16\
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    \15\ Natural Resources Defense Council v. EPA, 706 F.3d. 428 
(D.C. Cir. 2013) (``NRDC''). In NRDC, the court held that the EPA 
erred in implementing the 1997 PM<INF>2.5</INF> standards 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 [mu]m in diameter 
(PM<INF>10</INF>) 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 PM<INF>2.5</INF> standards under subpart 
4 because PM<INF>2.5</INF> falls within the statutory definition of 
PM<INF>10</INF> and is thus subject to the same statutory 
requirements as PM<INF>10</INF>. The court remanded the rule, 
without vacatur, and instructed the EPA ``to repromulgate these 
rules pursuant to Subpart 4 consistent with this opinion.''
    \16\ 79 FR 31566.
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    Effective May 7, 2015, the EPA reclassified the San Joaquin Valley 
as a Serious nonattainment area for the 1997 PM<INF>2.5</INF> NAAQS 
based on our determination that the area could not practicably attain 
these NAAQS by the April 5, 2015 attainment date.\17\ Upon 
reclassification as a Serious area, the San Joaquin Valley became 
subject to a December 31, 2015 deadline under CAA section 188(c)(2) to 
attain the 1997 PM<INF>2.5</INF> NAAQS. On February 9, 2016, the EPA 
proposed to grant the State's request for extensions of the December 
31, 2015 attainment date under CAA section 188(e), to December 31, 
2018, for the 1997 24-hour PM<INF>2.5</INF> NAAQS, and to December 31, 
2020, for the 1997 annual PM<INF>2.5</INF> NAAQS in the San Joaquin 
Valley.\18\ However, on October 6, 2016, after considering public 
comments, the EPA denied California's request for these extensions of 
the attainment dates.\19\ Consequently, on November 23, 2016, the EPA 
determined that the San Joaquin Valley had failed to attain the 1997 
PM<INF>2.5</INF> NAAQS by the December 31, 2015 Serious area attainment 
date.\20\ This determination triggered a requirement for California to 
submit, by December 31, 2016, a revised PM<INF>2.5</INF> attainment 
plan for the 1997 PM<INF>2.5</INF> NAAQS for the San Joaquin Valley 
that satisfies the requirements of CAA section 189(d).
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    \17\ 80 FR 18528 (April 7, 2015).
    \18\ 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 PM<INF>2.5</INF> NAAQS 
and related motor vehicle emission budgets, submitted June 25, 2015 
and August 13, 2015, respectively.
    \19\ 81 FR 69396. The EPA did not finalize the actions proposed 
on February 9, 2016, with respect to the submitted Serious area 
plan. Id. at 69400.
    \20\ 81 FR 84481.
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    On December 6, 2018, the EPA determined that California had failed 
to submit a complete Serious area and section 189(d) attainment plan 
for the 1997 PM<INF>2.5</INF> NAAQS, among other required SIP 
submissions for the San Joaquin Valley, by the submittal deadline.\21\ 
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 six 
months thereafter, unless the EPA affirmatively determines that the 
State has submitted a complete SIP addressing the identified 
deficiencies.\22\ The finding also triggered the obligation under CAA 
section 110(c) on the EPA to promulgate a federal implementation plan 
no later than two years after the finding, unless the State has 
submitted, and the EPA has approved, the required SIP

[[Page 38654]]

submittal.\23\ CARB submitted a revised attainment plan for the 1997 
PM<INF>2.5</INF> NAAQS, among other submissions, on May 10, 2019.\24\ 
This SIP revision is the subject of this proposal. On June 24, 2020, 
the EPA issued a letter finding the submittal complete and terminating 
the sanctions clocks under CAA section 179(a).\25\
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    \21\ 83 FR 62720.
    \22\ Id. at 62723.
    \23\ Id.
    \24\ Letter dated May 9, 2019, from Richard Corey, Executive 
Officer, CARB, to Mike Stoker, Regional Administrator, EPA Region 9.
    \25\ Letter dated June 24, 2020, from Elizabeth J. Adams, 
Director, Air and Radiation Division, EPA Region IX, to Richard W. 
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 
(PM<INF>2.5</INF>) National Ambient Air Quality Standards (NAAQS) 
and Termination of Clean Air Act (CAA) Sanction Clocks.''
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II. Summary and Completeness Review of the San Joaquin Valley PM2.5 
Plan

    The EPA is proposing action on portions of three SIP revisions 
submitted by CARB to meet CAA requirements for the 1997 annual 
PM<INF>2.5</INF> NAAQS in the San Joaquin Valley. Specifically, the EPA 
is proposing to act on those portions of the following two plan 
submissions that pertain to the 1997 annual PM<INF>2.5</INF> NAAQS: The 
``2018 Plan for the 1997, 2006, and 2012 PM<INF>2.5</INF> Standards,'' 
adopted by the SJVUAPCD on November 15, 2018, and by CARB on January 
24, 2019 (``2018 PM<INF>2.5</INF> Plan''); \26\ and the ``San Joaquin 
Valley Supplement to the 2016 State Strategy for the State 
Implementation Plan,'' adopted by CARB on October 25, 2018 (``Valley 
State SIP Strategy''). CARB submitted the 2018 PM<INF>2.5</INF> Plan 
and Valley State SIP Strategy to the EPA as a revision to the 
California SIP on May 10, 2019.\27\ We refer to these two SIP 
submissions collectively as the ``SJV PM<INF>2.5</INF> Plan'' or 
``Plan.''
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    \26\ The 2018 PM<INF>2.5</INF> Plan was developed jointly by 
CARB and the District.
    \27\ Letter dated May 9, 2019, from Richard Corey, Executive 
Officer, CARB, to Mike Stoker, Regional Administrator, EPA Region 9. 
The letter clarifies that the 2018 PM<INF>2.5</INF> Plan supersedes 
past submittals to the EPA that the agency has not yet acted on for 
the 1997 standards, including the 2015 Plan for the 1997 Standard 
(submitted by CARB on June 25, 2015) and motor vehicle emission 
budgets (submitted by CARB August 13, 2015). The EPA previously 
acted on those portions of the ``2018 Plan for the 1997, 2006, and 
2012 PM<INF>2.5</INF> Standards'' and the ``San Joaquin Valley 
Supplement to the 2016 State Strategy for the State Implementation 
Plan'' that pertain to the 2006 PM<INF>2.5</INF> NAAQS (85 FR 44192, 
July 22, 2020), and is not, at this time, proposing to act on those 
portions that pertain to the 1997 24-hour PM<INF>2.5</INF> NAAQS or 
the 2012 annual PM<INF>2.5</INF> NAAQS. We intend to act on these 
portions of the submitted SIP revisions in subsequent rulemakings.
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    The EPA is also proposing action on 2019 amendments to the regional 
air district residential wood-burning rule, SJVUAPCD Rule 4901, ``Wood 
Burning Fireplaces and Wood Burning Heaters'' (``Rule 4901''), adopted 
by the SJVUAPCD on June 20, 2019, and by CARB on July 19, 2019.\28\ 
These amendments include a contingency measure (in section 5.7.3 of the 
amended rule) that applies to the 1997 annual PM<INF>2.5</INF> NAAQS.
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    \28\ Letter dated July 19, 2019, from Richard W. Corey, 
Executive Officer, CARB, to Mike Stoker, Regional Administrator, EPA 
Region 9.
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    The SJV PM<INF>2.5</INF> Plan addresses the Serious area and CAA 
section 189(d) requirements for the 1997 PM<INF>2.5</INF> NAAQS in the 
San Joaquin Valley, including the State's demonstration that the area 
will attain the 1997 annual PM<INF>2.5</INF> NAAQS by December 31, 
2020. In this proposal, the EPA is proposing to act only on those 
portions of the SJV PM<INF>2.5</INF> Plan that pertain to the 1997 
annual PM<INF>2.5</INF> NAAQS. The EPA intends to act on the portions 
of the SJV PM<INF>2.5</INF> Plan that pertain to the 1997 24-hour 
PM<INF>2.5</INF> NAAQS and subsequent PM<INF>2.5</INF> NAAQS in 
separate rulemakings.
    CAA sections 110(a)(1) and (2) and 110(l) require each state to 
provide reasonable public notice and opportunity for public hearing 
prior to the adoption and submission of a SIP or SIP revision to the 
EPA. To meet this requirement, every SIP submission should include 
evidence that adequate public notice was given and that an opportunity 
for a public hearing was provided consistent with the EPA's 
implementing regulations in 40 CFR 51.102.
    CAA section 110(k)(1)(B) requires the EPA to determine whether a 
SIP submission is complete within 60 days of receipt. This section also 
provides that any plan that the EPA has not affirmatively determined to 
be complete or incomplete will become complete by operation of law six 
months after the date of submission. The EPA's SIP completeness 
criteria are found in 40 CFR part 51, Appendix V.

A. 2018 PM2.5 Plan

    The following portions of the 2018 PM<INF>2.5</INF> Plan and 
related support documents address both the Serious area requirements in 
CAA section 189(b) and the CAA section 189(d) requirements for the 1997 
annual PM<INF>2.5</INF> NAAQS in the San Joaquin Valley: (i) Chapter 4 
(``Attainment Strategy for PM<INF>2.5</INF>''), (ii) Chapter 5 
(``Demonstration of Federal Requirements for 1997 PM<INF>2.5</INF> 
Standards''); \29\ (iii) numerous appendices to the 2018 
PM<INF>2.5</INF> Plan; (iv) CARB's ``Staff Report, Review of the San 
Joaquin Valley 2018 Plan for the 1997, 2006, and 2012 PM<INF>2.5</INF> 
Standards,'' release date December 21, 2018 (``CARB Staff Report''); 
\30\ and (v) the State's and District's board resolutions adopting the 
2018 PM<INF>2.5</INF> Plan (CARB Resolution 19-1 and SJVUAPCD Governing 
Board Resolution 18-11-16).\31\
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    \29\ Chapter 6 (``Demonstration of Federal Requirements for the 
2006 PM<INF>2.5</INF> Standard: Serious Plan and Extension 
Request'') and Chapter 7 (``Demonstration of Federal Requirements 
for the 2012 PM<INF>2.5</INF> Standard'') of the 2018 
PM<INF>2.5</INF> Plan pertain to the 2006 PM<INF>2.5</INF> NAAQS and 
the 2012 PM<INF>2.5</INF> NAAQS, respectively. The EPA previously 
acted on those portions of the Plan that pertain to the 2006 
PM<INF>2.5</INF> NAAQS (85 FR 44192, July 22, 2020) and intends to 
act on those portions that pertain to the 1997 24-hour 
PM<INF>2.5</INF> NAAQS and 2012 PM<INF>2.5</INF> NAAQS in separate 
rulemakings.
    \30\ Letter dated December 11, 2019, from Richard Corey, 
Executive Officer, CARB, to Mike Stoker, Regional Administrator, EPA 
Region 9, transmitting the CARB Staff Report [on the 2018 
PM<INF>2.5</INF> Plan]. The CARB Staff Report includes CARB's review 
of, among other things, the 2018 PM<INF>2.5</INF> Plan's control 
strategy and attainment demonstration.
    \31\ CARB Resolution 19-1, ``2018 PM<INF>2.5</INF> State 
Implementation Plan for the San Joaquin Valley,'' January 24, 2019, 
and SJVUAPCD Governing Board Resolution 18-11-16, ``Adopting the 
[SJVUAPCD] 2018 Plan for the 1997, 2006, and 2012 PM<INF>2.5</INF> 
Standards,'' November 15, 2018.
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    The appendices to the 2018 PM<INF>2.5</INF> Plan that address the 
requirements for the 1997 annual PM<INF>2.5</INF> NAAQS include: (i) 
Appendix A (``Ambient PM<INF>2.5</INF> Data Analysis''); (ii) Appendix 
B (``Emissions Inventory''); (iii) Appendix C (``Stationary Source 
Control Measure Analyses''); (iv) Appendix D (``Mobile Source Control 
Measure Analyses''); (v) Appendix G (``Precursor Demonstration''); (vi) 
Appendix H (``RFP, Quantitative Milestones, and Contingency''); \32\ 
(vii) Appendix I (``New Source Review and Emission Reduction 
Credits''); (viii) Appendix J (``Modeling Emission Inventory''); (ix) 
Appendix K (``Modeling Attainment Demonstration''); and (x) Appendix L 
(``Modeling Protocol'').
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    \32\ Appendix H to 2018 PM<INF>2.5</INF> Plan, submitted 
February 11, 2020 via the EPA State Planning Electronic 
Collaboration System. Following the identification of a 
transcription error in the RFP tables of Appendix H, on February 11, 
2020, the State submitted a revised version of Appendix H that 
corrects the transcription error and provides additional information 
on the RFP demonstration. All references to Appendix H in this 
proposed rule are to the revised version submitted on February 11, 
2020, which replaces the version submitted with the 2018 
PM<INF>2.5</INF> Plan on May 10, 2019.
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    The District provided public notice and opportunity for public 
comment prior to its November 15, 2018 public hearing on and adoption 
of the 2018 PM<INF>2.5</INF> Plan.\33\ CARB also provided public notice 
and opportunity for public comment prior to its January 24, 2019 public 
hearing on and adoption of the

[[Page 38655]]

2018 PM<INF>2.5</INF> Plan.\34\ The SIP submission includes proof of 
publication of notices for the respective public hearings. It also 
includes copies of the written and oral comments received during the 
State's and District's public review processes and the agencies' 
responses thereto.\35\ Therefore, we find that the 2018 
PM<INF>2.5</INF> Plan meets the procedural requirements for public 
notice and hearing in CAA sections 110(a) and 110(l) and 40 CFR 51.102. 
The 2018 PM<INF>2.5</INF> Plan became complete by operation of law on 
November 10, 2019.
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    \33\ SJVUAPCD, ``Notice of Public Hearing for Adoption of 
Proposed 2018 PM<INF>2.5</INF> Plan for the 1997, 2006, and 2012 
Standards,'' October 16, 2018, and SJVUAPCD Governing Board 
Resolution 18-11-16.
    \34\ CARB, ``Notice of Public Meeting to Consider the 2018 
PM<INF>2.5</INF> State Implementation Plan for the San Joaquin 
Valley,'' December 21, 2018, and CARB Resolution 19-1.
    \35\ CARB, ``Board Meeting Comments Log,'' March 29, 2019; J&K 
Court Reporting, LLC, ``Meeting, State of California Air Resources 
Board,'' January 24, 2019 (transcript of CARB's public hearing), and 
2018 PM<INF>2.5</INF> Plan, Appendix M (``Summary of Significant 
Comments and Responses'').
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B. Valley State SIP Strategy

    CARB developed the ``Revised Proposed 2016 State Strategy for the 
State Implementation Plan'' (``2016 State Strategy'') to support 
attainment planning in the San Joaquin Valley and Los Angeles-South 
Coast Air Basin (``South Coast'') ozone nonattainment areas.\36\ In its 
resolution adopting the 2016 State Strategy (CARB Resolution 17-7), the 
Board found that the 2016 State Strategy would achieve 6 tons per day 
(tpd) of NO<INF>X</INF> emissions reductions and 0.1 tpd of direct 
PM<INF>2.5</INF> emissions reductions in the San Joaquin Valley by 2025 
and directed CARB staff to work with SJVUAPCD to identify additional 
reductions from sources under District regulatory authority as part of 
a comprehensive plan to attain the PM<INF>2.5</INF> standards for the 
San Joaquin Valley and to return to the Board with a commitment to 
achieve additional emission reductions from mobile sources.\37\
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    \36\ The EPA has approved certain commitments made by CARB in 
the 2016 State Strategy for purposes of attaining the ozone NAAQS in 
the San Joaquin Valley and South Coast ozone nonattainment areas 
(for example, see 84 FR 3302 (February 12, 2019) and 84 FR 52005 
(October 1, 2019)) and for attaining the 2006 PM<INF>2.5</INF> NAAQS 
in the San Joaquin Valley (85 FR 44192 (July 22, 2020)).
    \37\ CARB Resolution 17-7, ``2016 State Strategy for the State 
Implementation Plan,'' March 23, 2017, 6-7.
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    CARB responded to this resolution by developing and adopting the 
``San Joaquin Valley Supplement to the 2016 State Strategy for the 
State Implementation Plan'' (``Valley State SIP Strategy'') to support 
the 2018 PM<INF>2.5</INF> Plan. The State's May 10, 2019 SIP submission 
incorporates by reference the Valley State SIP Strategy as adopted by 
CARB on October 25, 2018 and submitted to the EPA on November 16, 
2018.\38\
---------------------------------------------------------------------------

    \38\ Letter dated May 9, 2019, from Richard Corey, Executive 
Officer, CARB, to Mike Stoker, Regional Administrator, EPA Region 9, 
2.
---------------------------------------------------------------------------

    The Valley State SIP Strategy includes an ``Introduction'' (Chapter 
1), a chapter on ``Measures'' (Chapter 2), and a ``Supplemental State 
Commitment from the Proposed State Measures for the Valley'' (Chapter 
3). Much of the content of the Valley State SIP Strategy is reproduced 
in Chapter 4 (``Attainment Strategy for PM<INF>2.5</INF>'') of the 2018 
PM<INF>2.5</INF> Plan.\39\ The Valley State SIP Strategy also includes 
CARB Resolution 18-49, which, among other things, commits CARB to 
achieve specific amounts of NO<INF>X</INF> and PM<INF>2.5</INF> 
emissions reductions by specific years, for purposes of attaining the 
PM<INF>2.5</INF> NAAQS in the San Joaquin Valley.\40\
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    \39\ For example, Table 2 (proposed mobile source measures and 
schedule), Table 3 (emissions reductions from proposed mobile source 
measures), and Table 4 (summary of emission reduction measures) of 
the Valley State SIP Strategy correspond to tables 4-8, 4-9, and 4-
7, respectively, of the 2018 PM<INF>2.5</INF> Plan, Chapter 4.
    \40\ CARB Resolution 18-49, ``San Joaquin Valley Supplement to 
the 2016 State Strategy for the State Implementation Plan,'' October 
25, 2018, 5.
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    CARB provided the required public notice and opportunity for public 
comment prior to its October 25, 2018 public hearing on and adoption of 
the Valley State SIP Strategy.\41\ The SIP submission includes proof of 
publication of the public notice for this public hearing. It also 
includes copies of the written and oral comments received during the 
State's public review process and CARB's responses thereto.\42\ 
Therefore, we find that the Valley State SIP Strategy meets the 
procedural requirements for public notice and hearing in CAA sections 
110(a) and 110(l) and 40 CFR 51.102. The Valley State SIP Strategy 
became complete by operation of law on November 10, 2019.
---------------------------------------------------------------------------

    \41\ CARB, ``Notice of Public Meeting to Consider the San 
Joaquin Valley Supplement to the 2016 State Strategy for the State 
Implementation Plan,'' September 21, 2018, and CARB Resolution 18-
49.
    \42\ CARB, ``Board Meeting Comments Log,'' November 2, 2018 and 
compilation of written comments; and J&K Court Reporting, LLC, 
``Meeting, State of California Air Resources Board,'' October 25, 
2018 (transcript of CARB's public hearing).
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C. District Rule 4901

    With respect to the District contingency measure, the District 
states in Appendix H of the 2018 PM<INF>2.5</INF> Plan that it will 
amend Rule 4901 to include a requirement to be triggered upon a 
determination by the EPA that the San Joaquin Valley failed to meet a 
regulatory requirement necessitating implementation of a contingency 
measure.\43\ On June 20, 2019, the District adopted amendments to Rule 
4901 including a contingency measure (in section 5.7.3 of the amended 
rule), and, as an attachment to a letter dated July 19, 2019, CARB 
submitted the amended rule to the EPA for approval.\44\ On July 22, 
2020, we approved Rule 4901, as amended June 20, 2019, into the SIP 
based on our conclusion that the rule meets the requirements for 
enforceability and for SIP revisions in CAA sections 110(a)(2)(A), 
110(l), and 193 but we did not evaluate section 5.7.3 of the amended 
rule for compliance with CAA requirements for contingency measures.\45\ 
As part of that rulemaking, we stated that we would determine in future 
actions whether section 5.7.3 of Rule 4901, in conjunction with other 
submitted provisions, meets the statutory and regulatory requirements 
for contingency measures.\46\ We are now evaluating section 5.7.3 of 
Rule 4901, as amended June 20, 2019, for compliance with the 
requirements for contingency measures for purposes of the 1997 annual 
PM<INF>2.5</INF> NAAQS.
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    \43\ 2018 PM<INF>2.5</INF> Plan, Appendix H, H-25.
    \44\ Letter dated July 19, 2019 from Richard W. Corey, Executive 
Officer, CARB, to Mike Stoker, Regional Administrator, EPA Region 9.
    \45\ 85 FR 44206 (July 22, 2020) (final approval of Rule 4901); 
85 FR 1131, 1132-33 (January 9, 2020) (proposed approval of Rule 
4901).
    \46\ 85 FR 1131, 1132-33.
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    Consistent with the requirements of 40 CFR part 51, Appendix V, we 
previously determined that CARB's submittal of the June 20, 2019 
revisions to Rule 4901 satisfied the procedural requirements for SIP 
revisions under CAA section 110 and the EPA's implementing 
regulations.\47\
---------------------------------------------------------------------------

    \47\ 85 FR 1131 (January 9, 2020) (proposed approval of revised 
Rule 4901) and 85 FR 44206 (July 22, 2020) (final approval of 
revised Rule 4901).
---------------------------------------------------------------------------

III. Clean Air Act Requirements for Serious PM2.5 Areas That Fail To 
Attain

    In the event that a Serious area fails to attain the 
PM<INF>2.5</INF> NAAQS by the applicable attainment date, CAA section 
189(d) requires that ``the State in which such area is located shall, 
after notice and opportunity for public comment, submit within 12 
months after the applicable attainment date, plan revisions which 
provide for attainment of the . . . standard. . .'' An attainment plan 
under section 189(d) must, among other things, demonstrate expeditious 
attainment of the NAAQS within the time period provided under CAA 
section 179(d)(3) and provide for annual reductions in emissions of 
direct PM<INF>2.5</INF> or a PM<INF>2.5</INF> plan precursor pollutant 
within the area of not less than five

[[Page 38656]]

percent per year from the most recent emissions inventory for the area 
until attainment.\48\ In addition to the requirement to submit control 
measures providing for a five percent reduction in emissions of certain 
pollutants on an annual basis, the EPA interprets CAA section 189(d) as 
requiring a state to submit an attainment plan that includes the same 
basic statutory plan elements that are required for other attainment 
plans.\49\ Specifically, a state must submit to the EPA its plan to 
meet the requirements of CAA section 189(d) in the form of a complete 
attainment plan submission that includes the following elements:
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    \48\ CAA section 189(d) and 40 CFR 51.1010(c).
    \49\ 81 FR 58010, 58098 (August 24, 2016).
---------------------------------------------------------------------------

    1. A comprehensive, accurate, current inventory of actual emissions 
from all sources of PM<INF>2.5</INF> and PM<INF>2.5</INF> precursors in 
the area;
    2. A control strategy that includes additional measures (beyond 
those already adopted in previous SIPs for the area as RACM/RACT, best 
available control measures/best available control technology (BACM/
BACT), and most stringent measures (if applicable)) that provide for 
attainment of the standards and, from the date of such submission until 
attainment, demonstrate that the plan will at a minimum achieve an 
annual five percent reduction in emissions of direct PM<INF>2.5</INF> 
or any PM<INF>2.5</INF> plan precursor;
    3. A demonstration (including air quality modeling) that the plan 
provides for attainment as expeditiously as practicable;
    4. Plan provisions that require RFP;
    5. Quantitative milestones that are to be achieved every three 
years until the area is redesignated attainment and that demonstrate 
RFP toward attainment by the applicable date;
    6. Contingency measures to be implemented if the area fails to meet 
any requirement concerning RFP or quantitative milestones or to attain 
by the applicable attainment date; and
    7. Provisions to assure that control requirements applicable to 
major stationary sources of PM<INF>2.5</INF> also apply to major 
stationary sources of PM<INF>2.5</INF> precursors, except where the 
state demonstrates to the EPA's satisfaction that such sources do not 
contribute significantly to PM<INF>2.5</INF> levels that exceed the 
standards in the area.
    A state with a Serious PM<INF>2.5</INF> nonattainment area that 
fails to attain the NAAQS by the applicable Serious area attainment 
date must also address any statutory requirements applicable to 
Moderate and Serious nonattainment area plans under CAA sections 172 
and 189 of the CAA to the extent that those requirements have not 
already been met.\50\
---------------------------------------------------------------------------

    \50\ Id. Because the EPA has not previously approved a SIP 
submission for the San Joaquin Valley as meeting the Serious area 
planning requirements under CAA sections 172 and 189 for the 1997 
annual PM<INF>2.5</INF> NAAQS, the EPA is evaluating relevant 
portions of the SJV PM<INF>2.5</INF> Plan for compliance with these 
requirements, in addition to the requirements of CAA section 189(d).
---------------------------------------------------------------------------

    A section 189(d) plan must demonstrate attainment as expeditiously 
as practicable, and no later than five years from the date of the EPA's 
determination that the area failed to attain, consistent with sections 
179(d)(3) and 172(a)(2) of the CAA.\51\ Pursuant to those provisions, 
the Administrator may also extend the attainment date to the extent the 
Administrator deems appropriate, for a period no greater than 10 years 
from the effective date of the EPA's determination that the area failed 
to attain, considering the severity of nonattainment and the 
availability and feasibility of pollution control measures.
---------------------------------------------------------------------------

    \51\ 81 FR 84481, 84482.
---------------------------------------------------------------------------

    The EPA provided its preliminary views on the CAA's requirements 
for particulate matter plans under part D, title I of the Act in the 
following guidance documents: (1) ``State Implementation Plans; General 
Preamble for the Implementation of Title I of the Clean Air Act 
Amendments of 1990'' (``General Preamble''); \52\ (2) ``State 
Implementation Plans; General Preamble for the Implementation of Title 
I of the Clean Air Act Amendments of 1990; Supplemental'' (``General 
Preamble Supplement''); \53\ and (3) ``State Implementation Plans for 
Serious PM-10 Nonattainment Areas, and Attainment Date Waivers for PM-
10 Nonattainment Areas Generally; Addendum to the General Preamble for 
the Implementation of Title I of the Clean Air Act Amendments of 1990'' 
(``General Preamble Addendum'').\54\ More recently, in an August 24, 
2016 final rule entitled, ``Fine Particulate Matter National Ambient 
Air Quality Standards: State Implementation Plan Requirements'' 
(``PM<INF>2.5</INF> 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 PM<INF>2.5</INF> standards.\55\ We discuss these 
regulatory requirements and interpretations of the Act as appropriate 
in our evaluation of the SJV PM<INF>2.5</INF> Plan that follows.
---------------------------------------------------------------------------

    \52\ 57 FR 13498 (April 16, 1992).
    \53\ 57 FR 18070 (April 28, 1992).
    \54\ 59 FR 41998 (August 16, 1994).
    \55\ 81 FR 58010.
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IV. Review of the San Joaquin Valley PM2.5 Plan

A. Emissions Inventories

1. Statutory and Regulatory Requirements
    CAA section 172(c)(3) requires that each SIP include a 
comprehensive, accurate, current inventory of actual emissions from all 
sources of the relevant pollutant or pollutants in the nonattainment 
area. The EPA discussed the emissions inventory requirements that apply 
to PM<INF>2.5</INF> nonattainment areas in the PM<INF>2.5</INF> SIP 
Requirements Rule and codified these requirements in 40 CFR 
51.1008.\56\ The EPA has also issued guidance concerning emissions 
inventories for PM<INF>2.5</INF> nonattainment areas.\57\
---------------------------------------------------------------------------

    \56\ Id. at 58098-58099.
    \57\ ``Emissions Inventory Guidance for Implementation of Ozone 
and Particulate Matter National Ambient Air Quality Standards 
(NAAQS) and Regional Haze Regulations,'' U.S. EPA, May 2017 
(``Emissions Inventory Guidance''), available at https://www.epa.gov/air-emissions-inventories/air-emissions-inventory-guidance-implementation-ozone-and-particulate.
---------------------------------------------------------------------------

    The base year emissions inventory should provide a state's best 
estimate of actual emissions from all sources of the relevant 
pollutants in the area, i.e., all emissions that contribute to the 
formation of a particular NAAQS pollutant. For the PM<INF>2.5</INF> 
NAAQS, the base year inventory must include direct PM<INF>2.5</INF> 
emissions, separately reported filterable and condensable 
PM<INF>2.5</INF> emissions,\58\ and emissions of all chemical 
precursors to the formation of secondary PM<INF>2.5</INF>: nitrogen 
oxides (NO<INF>X</INF>), sulfur dioxide (SO<INF>2</INF>), volatile 
organic compounds (VOC), and ammonia.\59\ In addition, the emissions 
inventory base year for a Serious PM<INF>2.5</INF> nonattainment area 
subject to CAA section 189(d) must be one of the three years for which 
monitored data were used to determine that the area failed to attain 
the PM<INF>2.5</INF> NAAQS by the applicable Serious area attainment 
date, or another technically appropriate year justified by the state in 
its Serious area SIP submission.\60\ A state's SIP submission must 
include documentation explaining how it calculated emissions data for 
the inventory. In estimating mobile source emissions, a state should 
use the latest emissions models and planning assumptions available at 
the time the SIP is developed. The latest EPA-approved version of 
California's mobile

[[Page 38657]]

source emission factor model for estimating tailpipe, brake, and tire 
wear emissions from on-road mobile sources that was available during 
the State's and District's development of the SJV PM<INF>2.5</INF> Plan 
was EMFAC2014.\61\ Following CARB's submission of the Plan, the EPA 
approved EMFAC2017, the latest revision to this mobile source emissions 
model, and established grace periods during which EMFAC2014 may 
continue to be used for transportation conformity purposes (i.e., new 
regional emissions analyses and CO, PM<INF>10</INF>, and 
PM<INF>2.5</INF> hot-spot analyses).\62\ States are also required to 
use the EPA's ``Compilation of Air Pollutant Emission Factors'' (``AP-
42'') road dust method for calculating re-entrained road dust emissions 
from paved roads.<SUP>63 64</SUP>
---------------------------------------------------------------------------

    \58\ The Emissions Inventory Guidance identifies the types of 
sources for which the EPA expects states to provide condensable PM 
emissions inventories. Emissions Inventory Guidance, section 4.2.1 
(``Condensable PM Emissions''), 63-65.
    \59\ 40 CFR 51.1008(c)(1).
    \60\ Id.
    \61\ 80 FR 77337 (December 14, 2015). EMFAC is short for 
EMission FACtor. The EPA announced the availability of the EMFAC2014 
model, effective on the date of publication in the Federal Register, 
for use in state implementation plan development and transportation 
conformity in California. Upon that action, EMFAC2014 was required 
to be used for all new regional emissions analyses and CO, 
PM<INF>10</INF>, and PM<INF>2.5</INF> hot-spot analyses that were 
started on or after December 14, 2017, which was the end of the 
grace period for using the prior mobile source emissions model, 
EMFAC2011.
    \62\ 84 FR 41717 (August 15, 2019). The grace period for new 
regional emissions analyses begins on August 15, 2019 and ends on 
August 16, 2021, while the grace period for hot-spot analyses begins 
on August 15, 2019 and ends on August 17, 2020. 84 FR 41717, 41720.
    \63\ The EPA released an update to AP-42 in January 2011 that 
revised the equation for estimating paved road dust emissions based 
on an updated data regression that included new emission tests 
results. 76 FR 6328 (February 4, 2011). CARB used the revised 2011 
AP-42 methodology in developing on-road mobile source emissions; see 
http://www.arb.ca.gov/ei/areasrc/fullpdf/full7-9_2016.pdf.
    \64\ AP-42 has been published since 1972 as the primary source 
of the EPA's emission factor information and is available at https://www.epa.gov/air-emissions-factors-and-quantification/ap-42-compilation-air-emissions-factors. It contains emission factors and 
process information for more than 200 air pollution source 
categories. A source category is a specific industry sector or group 
of similar emitting sources. The emission factors have been 
developed and compiled from source test data, material balance 
studies, and engineering estimates.
---------------------------------------------------------------------------

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

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

2. Summary of the State's Submission
    Summaries of the planning emissions inventories for direct 
PM<INF>2.5</INF> and PM<INF>2.5</INF> precursors (NO<INF>X</INF>, 
SO<INF>X</INF>,\68\ VOC,\69\ and ammonia) and the documentation for the 
inventories for the San Joaquin Valley PM<INF>2.5</INF> nonattainment 
area are included in Appendix B (``Emissions Inventory'') and Appendix 
I (``New Source Review and Emission Reduction Credits'') of the 2018 
PM<INF>2.5</INF> Plan.
---------------------------------------------------------------------------

    \68\ The SJV PM<INF>2.5</INF> Plan generally uses ``sulfur 
oxides'' or ``SO<INF>X</INF>'' in reference to SO<INF>2</INF> as a 
precursor to the formation of PM<INF>2.5</INF>. We use 
SO<INF>X</INF> and SO<INF>2</INF> interchangeably throughout this 
notice.
    \69\ The SJV PM<INF>2.5</INF> Plan generally uses ``reactive 
organic gasses'' or ``ROG'' in reference to VOC as a precursor to 
the formation of PM<INF>2.5</INF>. We use ROG and VOC 
interchangeably throughout this notice.
---------------------------------------------------------------------------

    CARB and District staff worked together to develop the emissions 
inventories for the San Joaquin Valley PM<INF>2.5</INF> nonattainment 
area. The District worked with operators of the stationary facilities 
in the nonattainment area to develop the stationary source emissions 
estimates. The responsibility for developing emissions estimates for 
area sources such as agricultural burning and paved road dust was 
shared by the District and CARB. CARB staff developed the emissions 
inventories for both on-road and non-road mobile sources.\70\
---------------------------------------------------------------------------

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

    The Plan includes winter (24-hour) average and annual average daily 
planning inventories for the 2013 base year, which were modeled from 
the 2012 emissions inventory, and estimated emissions for forecasted 
years from 2017 through 2028 for the attainment and RFP demonstrations 
for the 1997, 2006, and 2012 PM<INF>2.5</INF> NAAQS.\71\ In this 
proposal, we are proposing action on those winter average and annual 
average emissions inventories necessary to support the attainment plan 
for the 1997 annual PM<INF>2.5</INF> NAAQS--i.e., the 2013 base year 
inventory, forecasted inventories for the RFP milestone years of 2017, 
2020 (attainment year), and 2023 (post-attainment milestone year), and 
additional forecasted inventories for 2018 and 2019 to support the five 
percent annual emission reduction demonstration. Each inventory 
includes emissions from stationary, area, on-road, and non-road 
sources.
---------------------------------------------------------------------------

    \71\ 2018 PM<INF>2.5</INF> Plan, Appendix B, B-18 to B-19. The 
winter average daily planning inventory corresponds to the months of 
November through April when daily ambient PM<INF>2.5</INF> 
concentrations are typically highest. The base year inventory is 
from the California Emissions Inventory Development and Reporting 
System (CEIDARS) and future year inventories were estimated using 
the California Emission Projection Analysis Model (CEPAM), 2016 SIP 
Baseline Emission Projections, version 1.05.
---------------------------------------------------------------------------

    The base year inventories for stationary sources were developed 
using actual emissions reports from facility operators. The State 
developed the base year emissions inventory for area sources using the 
most recent models and methodologies available at the time the State 
was developing the Plan.\72\ The Plan also includes background, 
methodology, and inventories of condensable and filterable 
PM<INF>2.5</INF> emissions from stationary point and non-point 
combustion sources that are expected to generate condensable 
PM<INF>2.5</INF>.\73\ CARB used EMFAC2014 to estimate on-road motor 
vehicle emissions based on transportation activity data from the 2014 
Regional Transportation Plan (2014 RTP) adopted by the transportation 
planning agencies in the San Joaquin Valley.\74\ Re-entrained paved 
road dust emissions were calculated using a CARB methodology consistent 
with the EPA's AP-42 road dust methodology.\75\
---------------------------------------------------------------------------

    \72\ 2018 PM<INF>2.5</INF> Plan, Appendix B, section B.2 
(``Emissions Inventory Summary and Methodology'').
    \73\ Id. at B-42 to B-44.
    \74\ Id. at B-37.
    \75\ Id. at B-28.
---------------------------------------------------------------------------

    CARB developed the emissions forecasts by applying growth and 
control profiles to the base year inventory. CARB's mobile source 
emissions projections take into account predicted activity rates and 
vehicle fleet turnover by vehicle model year and adopted controls.\76\ 
In addition, the Plan states that the District is providing for use of 
pre-base year ERCs as offsets by accounting for such ERCs in the

[[Page 38658]]

projected 2025 emissions inventory.\77\ The 2018 PM<INF>2.5</INF> Plan 
identifies growth factors, control factors, and estimated offset use 
between 2013 and 2025 for direct PM<INF>2.5</INF>, NO<INF>X</INF>, 
SO<INF>X</INF>, and VOC emissions by source category and lists all pre-
base year ERCs issued by the District for PM<INF>10</INF>, 
NO<INF>X</INF>, SO<INF>X</INF>, and VOC emissions, by facility.\78\
---------------------------------------------------------------------------

    \76\ Id. at B-18 and B-19.
    \77\ 2018 PM<INF>2.5</INF> Plan, Appendix I, I-1 to I-5.
    \78\ Id. at tables I-1 to I-5.
---------------------------------------------------------------------------

    Table 1 provides a summary of the winter (24-hour) average 
inventories in tons per day (tpd) of direct PM<INF>2.5</INF> and 
PM<INF>2.5</INF> precursors for the 2013 base year. Table 2 provides a 
summary of annual average inventories of direct PM<INF>2.5</INF> and 
PM<INF>2.5</INF> precursors for the 2013 base year. These annual 
average inventories provide the basis for the control measure analysis 
and the RFP and attainment demonstrations in the SJV PM<INF>2.5</INF> 
Plan.

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


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

3. The EPA's Evaluation and Proposed Action
    We have reviewed the 2013 base year emissions inventories in the 
SJV PM<INF>2.5</INF> Plan and emissions inventory estimation 
methodologies used by California for consistency with CAA requirements 
and the EPA's guidance. We find that the inventories are based on the 
most current and accurate information available to the State and 
District at the time they were developing the Plan and inventories, 
including the latest version of California's mobile source emissions 
model that had been approved by the EPA at the time, EMFAC2014. The 
inventories comprehensively address all source categories in the San 
Joaquin Valley PM<INF>2.5</INF> nonattainment area and are consistent 
with the EPA's inventory guidance.
    In accordance with 40 CFR 51.1008(c)(1), the 2013 base year is one 
of the three years for which monitored data were used to determine that 
the San Joaquin Valley area failed to attain the PM<INF>2.5</INF> NAAQS 
by the applicable Serious area attainment date for the 1997 annual 
PM<INF>2.5</INF> NAAQS,\79\ and it represents actual annual average 
emissions of all sources within the nonattainment area. Direct 
PM<INF>2.5</INF> and PM<INF>2.5</INF> precursors are included in the 
inventories, and filterable and condensable direct PM<INF>2.5</INF> 
emissions are identified separately.
---------------------------------------------------------------------------

    \79\ 81 FR 84481, 84482 (November 23, 2016).
---------------------------------------------------------------------------

    For these reasons, we are proposing to approve the 2013 base year 
emissions inventories in the SJV PM<INF>2.5</INF> Plan for the 1997 
annual PM<INF>2.5</INF> NAAQS as meeting the requirements of CAA 
section 172(c)(3) and 40 CFR 51.1008.

B. PM2.5 Precursors

1. Statutory and Regulatory Requirements
    The composition of PM<INF>2.5</INF> is complex and highly variable 
due in part to the large contribution of secondary PM<INF>2.5</INF> to 
total fine particle mass in most locations, and to the complexity of 
secondary particle formation processes. A large number of possible 
chemical reactions, often non-linear in nature, can convert gaseous 
NO<INF>X</INF>, SO<INF>2</INF>, VOC, and ammonia to PM<INF>2.5</INF>, 
making them precursors to PM<INF>2.5</INF>.\80\ Formation of secondary 
PM<INF>2.5</INF> may also depend on atmospheric conditions, including 
solar radiation, temperature, and relative humidity, and the 
interactions of precursors with preexisting particles and with cloud or 
fog droplets.\81\
---------------------------------------------------------------------------

    \80\ ``Air Quality Criteria for Particulate Matter'' (EPA/600/P-
99/002aF), EPA, October 2004, Chapter 3.
    \81\ ``Regulatory Impact Analysis for the Final Revisions to the 
National Ambient Air Quality Standards for Particulate Matter'' 
(EPA/452/R-12-005), EPA, December 2012), 2-1.
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    Under subpart 4 of part D, title I of the CAA and the 
PM<INF>2.5</INF> SIP Requirements Rule, each state containing a 
PM<INF>2.5</INF> nonattainment area must evaluate all PM<INF>2.5</INF> 
precursors for regulation unless, for any given PM<INF>2.5</INF> 
precursor, the state demonstrates to the Administrator's satisfaction 
that such precursor does not contribute significantly to 
PM<INF>2.5</INF> levels that exceed the NAAQS in the nonattainment 
area.\82\ The provisions of

[[Page 38659]]

subpart 4 do not define the term ``precursor'' for purposes of 
PM<INF>2.5</INF>, nor do they explicitly require the control of any 
specifically identified PM<INF>2.5</INF> precursor. The statutory 
definition of ``air pollutant,'' however, provides that the term 
``includes any precursors to the formation of any air pollutant, to the 
extent the Administrator has identified such precursor or precursors 
for the particular purpose for which the term `air pollutant' is 
used.'' \83\ The EPA has identified NO<INF>X</INF>, SO<INF>2</INF>, 
VOC, and ammonia as precursors to the formation of 
PM<INF>2.5</INF>.\84\ Accordingly, the attainment plan requirements of 
subpart 4 apply to emissions of all four precursor pollutants and 
direct PM<INF>2.5</INF> from all types of stationary, area, and mobile 
sources, except as otherwise provided in the Act (e.g., CAA section 
189(e)).
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    \82\ 81 FR 58010, 58017-58020.
    \83\ CAA section 302(g).
    \84\ 81 FR 58010, 58015.
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    Section 189(e) of the Act requires that the control requirements 
for major stationary sources of direct PM<INF>10</INF> also apply to 
major stationary sources of PM<INF>10</INF> precursors, except where 
the Administrator determines that such sources do not contribute 
significantly to PM<INF>10</INF> levels that exceed the standard in the 
area. Section 189(e) contains the only express exception to the control 
requirements under subpart 4 (e.g., requirements for RACM and RACT, 
BACM and BACT, most stringent measures, and new source review (NSR)) 
for sources of direct PM<INF>2.5</INF> and PM<INF>2.5</INF> precursor 
emissions. Although section 189(e) explicitly addresses only major 
stationary sources, the EPA interprets the Act as authorizing it also 
to determine, under appropriate circumstances, that regulation of 
specific PM<INF>2.5</INF> precursors from other source categories in a 
given nonattainment area is not necessary.\85\ For example, under the 
EPA's longstanding interpretation of the control requirements that 
apply to stationary, area, and mobile sources of PM<INF>10</INF> 
precursors in the nonattainment area under CAA section 172(c)(1) and 
subpart 4,\86\ a state may demonstrate in a SIP submission that control 
of a certain precursor pollutant is not necessary in light of its 
insignificant contribution to ambient PM<INF>10</INF> levels in the 
nonattainment area.\87\
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    \85\ Id. at 58018-58019.
    \86\ General Preamble, 57 FR 13498, 13539-13542.
    \87\ Courts have upheld this approach to the requirements of 
subpart 4 for PM<INF>10</INF>. See, e.g., Assoc. of Irritated 
Residents v. EPA, et al., 423 F.3d 989 (9th Cir. 2005).
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    Under the PM<INF>2.5</INF> SIP Requirements Rule, a state may elect 
to submit to the EPA a ``comprehensive precursor demonstration'' for a 
specific nonattainment area to show that emissions of a particular 
precursor from all existing sources located in the nonattainment area 
do not contribute significantly to PM<INF>2.5</INF> levels that exceed 
the standards in the area.\88\ If the EPA determines that the 
contribution of the precursor to PM<INF>2.5</INF> levels in the area is 
not significant and approves the demonstration, the state is not 
required to control emissions of the relevant precursor from existing 
sources in the attainment plan.\89\
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    \88\ 40 CFR 51.1006(a)(1).
    \89\ Id.
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    In addition, in May 2019, the EPA issued the ``Fine Particulate 
Matter (PM<INF>2.5</INF>) Precursor Demonstration Guidance'' 
(``PM<INF>2.5</INF> Precursor Guidance''),\90\ which provides 
recommendations to states for analyzing nonattainment area 
PM<INF>2.5</INF> emissions and developing such optional precursor 
demonstrations, consistent with the PM<INF>2.5</INF> SIP Requirements 
Rule. The PM<INF>2.5</INF> Precursor Guidance builds upon the draft 
version of the guidance, released on November 17, 2016 (``Draft 
PM<INF>2.5</INF> Precursor Guidance''), which CARB referenced in 
developing its precursor demonstration in the SJV PM<INF>2.5</INF> 
Plan.\91\ The EPA's recommendations in the PM<INF>2.5</INF> Precursor 
Guidance are essentially the same as those in the Draft 
PM<INF>2.5</INF> Precursor Guidance, including the recommended annual 
contribution threshold of 0.2 [mu]g/m\3\.
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    \90\ ``PM<INF>2.5</INF> Precursor Demonstration Guidance,'' EPA-
454/R-19-004, May 2019, including memorandum dated May 30, 2019 from 
Scott Mathias, Acting Director, Air Quality Policy Division and 
Richard Wayland, Director, Air Quality Assessment Division, Office 
of Air Quality Planning and Standards (OAQPS), EPA to Regional Air 
Division Directors, Regions 1-10, EPA.
    \91\ ``PM<INF>2.5</INF> Precursor Demonstration Guidance, Draft 
for Public Review and Comments,'' EPA-454/P-16-001, November 17, 
2016, including memorandum dated November 17, 2016 from Stephen D. 
Page, Director, OAQPS, EPA to Regional Air Division Directors, 
Regions 1-10, EPA.
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    We are evaluating the SJV PM<INF>2.5</INF> Plan in accordance with 
the presumption embodied within subpart 4 that all PM<INF>2.5</INF> 
precursors must be addressed in the State's evaluation of potential 
control measures, unless the State adequately demonstrates that 
emissions of a particular precursor or precursors do not contribute 
significantly to ambient PM<INF>2.5</INF> levels that exceed the 
PM<INF>2.5</INF> NAAQS in the nonattainment area. In reviewing any 
determination by the State to exclude a PM<INF>2.5</INF> precursor from 
the required evaluation of potential control measures, we consider both 
the magnitude of the precursor's contribution to ambient 
PM<INF>2.5</INF> concentrations in the nonattainment area and the 
sensitivity of ambient PM<INF>2.5</INF> concentrations in the area to 
reductions in emissions of that precursor.
2. Summary of the State's Submission
    The State presents a summary of its PM<INF>2.5</INF> precursor 
analysis in Chapter 5 of the 2018 PM<INF>2.5</INF> Plan and the full 
precursor demonstration in Appendix G (``Precursor Demonstration'') of 
the 2018 PM<INF>2.5</INF> Plan.\92\ Additional modeling results are 
presented in Appendix K (``Modeling Attainment Demonstration''), 
section 5.6 (``PM<INF>2.5</INF> Precursor Sensitivity Analysis''). CARB 
also provided clarifying information on its precursor assessment, 
including an Attachment A to its letter transmitting the 2018 
PM<INF>2.5</INF> Plan to the EPA \93\ and further clarifications in 
five email transmittals.\94\ The CARB Staff Report contains additional 
discussion of the role of ammonia in the formation of ammonium nitrate 
and the role of VOC in the formation of ammonium nitrate and secondary 
organic aerosol.\95\
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    \92\ A copy of the contents of Appendix G appears in the CARB 
Staff Report, Appendix C4 (``Precursor Demonstrations for Ammonia, 
SO<INF>X</INF>, and ROG'').
    \93\ Letter dated May 9, 2019, from Richard Corey, Executive 
Officer, CARB, to Michael Stoker, Regional Administrator, EPA Region 
9, Attachment A (``Clarifying information for the San Joaquin Valley 
2018 Plan regarding model sensitivity related to ammonia and ammonia 
controls'').
    \94\ Email dated June 20, 2019, from Jeremy Avise, CARB, to 
Scott Bohning, EPA Region IX, Subject: ``RE: SJV model disbenefit 
from SO<INF>X</INF> reduction,'' with attachment (``CARB's June 2019 
Precursor Clarification''); email dated September 19, 2019, from 
Jeremy Avise, CARB, to Scott Bohning, EPA Region IX, Subject: ``FW: 
SJV species responses,'' with attachments (``CARB's September 2019 
Precursor Clarification''); email dated October 18, 2019, from Laura 
Carr, CARB, to Scott Bohning, Jeanhee Hong, and Rory Mays, EPA 
Region IX, Subject: ``Clarifying information on ammonia,'' with 
attachment ``Clarifying Information on Ammonia'' (``CARB's October 
2019 Precursor Clarification''); email dated April 19, 2021, from 
Laura Carr, CARB, to Rory Mays, EPA Region IX, Subject: ``Ammonia 
update,'' with attachment ``Update on Ammonia in the San Joaquin 
Valley'' (``CARB's April 19, 2021 Precursor Clarification''); and 
email dated April 26, 2021, from Laura Carr, CARB, to Scott Bohning, 
EPA Region IX, Subject: ``RE: Ammonia update,'' with attachment 
``Ammonia in San Joaquin Valley'' (``CARB's April 26, 2021 Precursor 
Clarification'').
    \95\ CARB Staff Report, Appendix C, 9-16. The CARB Staff Report, 
Appendix C4 (``Precursor Demonstrations for Ammonia, SO<INF>X</INF>, 
and ROG'') is very similar to the contents of Appendix G of the 2018 
PM<INF>2.5</INF> Plan.
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    The Plan provides both concentration-based and sensitivity-based 
analyses of precursor contributions to ambient PM<INF>2.5</INF> 
concentrations in the San Joaquin Valley. The State supplemented the 
sensitivity analysis, particularly for ammonia, with additional 
information, including factors identified in the PM<INF>2.5</INF> 
Precursor Guidance, such as emission trends, the appropriateness of 
future year versus base year sensitivity, available emission controls, 
and the

[[Page 38660]]

severity of nonattainment.\96\ These analyses led the State to conclude 
that direct PM<INF>2.5</INF> and NO<INF>X</INF> emissions contribute 
significantly to ambient PM<INF>2.5</INF> levels that exceed the 
PM<INF>2.5</INF> NAAQS in the San Joaquin Valley while ammonia, 
SO<INF>X</INF>, and VOC do not contribute significantly to such 
exceedances.\97\ We summarize the State's analysis and conclusions 
below. For a more detailed summary of the precursor demonstration in 
the Plan, please refer to the EPA's ``Technical Support Document, EPA 
Evaluation of PM<INF>2.5</INF> Precursor Demonstration, San Joaquin 
Valley PM<INF>2.5</INF> Plan for the 2006 PM<INF>2.5</INF> NAAQS,'' 
February 2020 (``EPA's PM<INF>2.5</INF> Precursor TSD'').
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    \96\ PM<INF>2.5</INF> Precursor Guidance, 18-19 (consideration 
of additional information), 31 (available emission controls), and 
35-36 (appropriateness of future year versus base year sensitivity).
    \97\ Direct PM<INF>2.5</INF> emissions are considered a primary 
source of ambient PM<INF>2.5</INF> (i.e., no further formation in 
the atmosphere is required), and therefore is not considered a 
precursor pollutant under subpart 4, which may differ from a more 
generalized understanding of what contributes to ambient 
PM<INF>2.5</INF>.
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    For ammonia, SO<INF>X</INF>, and VOC, CARB assessed the 2015 annual 
average concentration of each precursor in ambient PM<INF>2.5</INF> at 
Bakersfield, for which the necessary speciated PM<INF>2.5</INF> data 
are available and where the highest PM<INF>2.5</INF> design values have 
been recorded in most years, and compared those concentrations to the 
recommended annual average contribution threshold of 0.2 [mu]g/m\3\ 
from the Draft PM<INF>2.5</INF> Precursor Guidance, which was available 
at the time the State developed the SIP.\98\ The contributions of 
ammonia, SO<INF>X</INF>, and VOC were 5.2 [mu]g/m\3\, 1.6 [mu]g/m\3\, 
and 6.2 [mu]g/m\3\, respectively. Given that these levels are well 
above the EPA's 0.2 [mu]g/m\3\ recommended contribution threshold, the 
State proceeded with a sensitivity-based analysis.
---------------------------------------------------------------------------

    \98\ 2018 PM<INF>2.5</INF> Plan, Appendix G, 3. The Plan does 
not present a concentration-based analysis for the 24-hour average 
concentrations in the San Joaquin Valley. Instead, CARB relied on 
the annual average concentration-based analysis as an interim step 
to the sensitivity-based analysis, for which CARB assessed the 
sensitivity of both 24-hour average and annual average ambient 
PM<INF>2.5</INF> concentrations to precursor emissions reductions. 
Separately, the Plan presents a graphical representation of annual 
average ambient PM<INF>2.5</INF> components (i.e., crustal 
particulate matter, elemental carbon, organic matter, ammonium 
sulfate, and ammonium nitrate) for 2011-2013 for Bakersfield, 
Fresno, and Modesto. 2018 PM<INF>2.5</INF> Plan, Chapter 3, 3-3 to 
3-4.
---------------------------------------------------------------------------

    The State's sensitivity-based analysis used the same Community 
Multiscale Air Quality (CMAQ) modeling platform as that used for the 
Plan's attainment demonstration. The State modeled the sensitivity of 
ambient PM<INF>2.5</INF> concentration in the San Joaquin Valley to 30 
percent and 70 percent emissions reductions in 2013, 2020, and 2024 for 
each of ammonia, SO<INF>X</INF>, and VOC. The State estimated baseline 
(2013, 2020, and 2024) design values for PM<INF>2.5</INF> using 
relative response factors (RRFs) and calculated the ammonia, 
SO<INF>X</INF>, and VOC precursor contribution for a given year and for 
each sensitivity scenario (30 percent and 70 percent emissions 
reductions) as the difference between its baseline design value and the 
design value for each sensitivity scenario.\99\ Based on these analyses 
and supporting information, the State concludes that ammonia, 
SO<INF>X</INF>, and VOC emissions do not contribute significantly to 
PM<INF>2.5</INF> levels that exceed the 1997 annual PM<INF>2.5</INF> 
NAAQS in the San Joaquin Valley.
---------------------------------------------------------------------------

    \99\ This procedure is the procedure recommended by the EPA. 
PM<INF>2.5</INF> Precursor Guidance, 37.
---------------------------------------------------------------------------

3. The EPA's Evaluation and Proposed Action
    As discussed in section IV of this proposal, the EPA is proposing 
to disapprove the attainment demonstration and related elements in the 
SJV PM<INF>2.5</INF> Plan for the 1997 annual PM<INF>2.5</INF> NAAQS, 
including the five percent annual emission reductions demonstration, 
reasonable further progress (RFP) demonstration, and quantitative 
milestones, based on ambient monitoring data that show that the Plan 
was insufficient to achieve attainment of the 1997 annual 
PM<INF>2.5</INF> NAAQS by December 31, 2020, the State's projected 
attainment date. Given that we are proposing to disapprove the 
attainment demonstration, and given that the precursor demonstration 
for the 1997 annual PM<INF>2.5</INF> NAAQS largely relies on the 
technical analyses and assumptions that provide the basis for the 
attainment demonstration, we are also proposing to disapprove the 
precursor demonstration in the SJV PM<INF>2.5</INF> Plan for the 1997 
annual PM<INF>2.5</INF> NAAQS. Therefore, all precursors to the 
formation of PM<INF>2.5</INF> in the San Joaquin Valley (i.e., 
NO<INF>X</INF>, ammonia, SO<INF>X</INF>, and VOC) remain 
``PM<INF>2.5</INF> plan precursors'' as defined in 40 CFR 51.1000 for 
purposes of the 1997 annual PM<INF>2.5</INF> NAAQS for the Plan that is 
the subject of this proposal.
    If the EPA takes final action on the SJV PM<INF>2.5</INF> Plan as 
proposed, California will be required to develop and submit a revised 
plan for the San Joaquin Valley area that addresses the applicable CAA 
requirements, including the requirements of CAA section 189(d). Under 
40 CFR 51.1006, the State will be required to submit an updated 
precursor demonstration if it seeks to exempt sources of a particular 
precursor from control requirements in the new Serious area attainment 
demonstration. For these reasons, and because we are proposing to 
disapprove the precursor demonstration on the basis of our proposed 
disapproval of the attainment demonstration, we are not providing a 
full evaluation of the precursor demonstration for the 1997 annual 
PM<INF>2.5</INF> NAAQS in the SJV PM<INF>2.5</INF> Plan at this time.

C. Attainment Plan Control Strategy

1. Statutory and Regulatory Requirements
    The overarching requirement for the CAA section 189(d) attainment 
control strategy is that it provides for attainment of the standards as 
expeditiously as practicable.\100\ The control strategy must include 
any additional measures (beyond those already adopted in previous SIPs 
for the area as RACM/RACT or BACM/BACT) that are needed for the area to 
attain expeditiously. This includes reassessing any measures previously 
rejected during the development of any Moderate area or Serious area 
attainment plan control strategy.\101\ The plan must also demonstrate 
that it will, at a minimum, achieve an annual five percent reduction in 
emissions of direct PM<INF>2.5</INF> or any PM<INF>2.5</INF> plan 
precursor from sources in the area until attainment, based on the most 
recent emissions inventory for the area.\102\
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    \100\ 81 FR 58010, 58100.
    \101\ 40 CFR 50.1010(c)(2)(ii).
    \102\ CAA section 189(d) and 40 CFR 51.1010(c).
---------------------------------------------------------------------------

    In the PM<INF>2.5</INF> SIP Requirements Rule, the EPA clarified 
its interpretation of the statutory language in CAA section 189(d) 
requiring a state to submit a new attainment plan to achieve annual 
reductions ``from the date of such submission until attainment,'' to 
mean annual reductions beginning from the due date of such submission 
until the new projected attainment date for the area based on the new 
or additional control measures identified to achieve at least five 
percent emissions reductions annually.\103\ This interpretation is 
intended to make clear that even if a state is late in submitting its 
CAA section 189(d) plan, the area must still achieve its annual five 
percent emission reductions beginning from the date by

[[Page 38661]]

which the state was required to make its CAA section 189(d) submission, 
not by some later date. Because the deadline for California to submit a 
section 189(d) plan for the 1997 PM<INF>2.5</INF> NAAQS in the San 
Joaquin Valley was December 31, 2016, one year after the December 31, 
2015 attainment date for these NAAQS under CAA section 188(c)(2), the 
starting point for the five percent emission reduction requirement 
under section 189(d) for this area is 2017.
---------------------------------------------------------------------------

    \103\ 81 FR 58010, 58101. The new projected attainment date is 
established by the EPA in accordance with the provisions of CAA 
sections 179(d)(3) and 172(a)(2), which require that the new 
attainment date be as expeditious as practicable but no later than 5 
years from the date of publication in the Federal Register of the 
EPA's determination that the area failed to attain the relevant 
NAAQS, except that the EPA may extend the attainment date by up to 5 
additional years based on the severity of nonattainment and the 
availability and feasibility of pollution control measures. Id. at 
58103.
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    As discussed in section III of this proposed rule, a state with a 
Serious PM<INF>2.5</INF> nonattainment area that fails to attain the 
NAAQS by the applicable Serious area attainment date must also address 
any statutory requirements applicable to Moderate and Serious 
nonattainment area plans under CAA sections 172 and 189 of the CAA to 
the extent that those requirements have not already been met. Because 
the EPA has not previously taken action to approve the California SIP 
as meeting the Serious nonattainment area planning requirements under 
CAA sections 172 and 189 for the 1997 annual PM<INF>2.5</INF> NAAQS for 
the San Joaquin Valley area, the EPA is reviewing the SJV 
PM<INF>2.5</INF> Plan for compliance with those requirements, including 
the requirement for BACM.
    Section 189(b)(1)(B) of the Act requires for any Serious 
PM<INF>2.5</INF> nonattainment area that the state submit provisions to 
assure that BACM for the control of PM<INF>2.5</INF> and 
PM<INF>2.5</INF> precursors shall be implemented no later than four 
years after the date the area is reclassified as a Serious area. The 
EPA has defined BACM in the PM<INF>2.5</INF> SIP Requirements Rule to 
mean ``any technologically and economically feasible control measure 
that . . . can achieve greater permanent and enforceable emissions 
reductions of 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 best available control technology (BACT).'' \104\
---------------------------------------------------------------------------

    \104\ 40 CFR 51.1000 (definitions). In longstanding guidance, 
the EPA has similarly defined BACM to mean, ``among other things, 
the maximum degree of emissions reduction achievable for a source or 
source category, which is determined on a case-by-case basis 
considering energy, environmental, and economic impacts.'' General 
Preamble Addendum, 42010, 42013.
---------------------------------------------------------------------------

    The EPA generally considers BACM a control level that goes beyond 
existing RACM-level controls, for example by expanding the use of RACM 
controls or by requiring preventative measures instead of 
remediation.\105\ Indeed, as implementation of BACM and BACT is 
required when a Moderate nonattainment area is reclassified as Serious 
due to its inability to attain the NAAQS through implementation of 
``reasonable'' measures, it is logical that ``best'' control measures 
should represent a more stringent and potentially more costly level of 
control.\106\ If RACM and RACT level controls of emissions have been 
insufficient to reach attainment, the CAA contemplates the 
implementation of more stringent controls, controls on more sources, or 
other adjustments to the control strategy necessary to attain the NAAQS 
in the area.
---------------------------------------------------------------------------

    \105\ 81 FR 58010, 58081 and General Preamble Addendum, 42011, 
42013.
    \106\ Id. and General Preamble Addendum, 42009-42010.
---------------------------------------------------------------------------

    Consistent with longstanding guidance provided in the General 
Preamble Addendum, the preamble to the PM<INF>2.5</INF> SIP 
Requirements Rule discusses the following steps for determining BACM 
and BACT:
    (1) Develop a comprehensive emissions 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.\107\
---------------------------------------------------------------------------

    \107\ 81 FR 58010, 58083-58085.
---------------------------------------------------------------------------

    The EPA allows consideration of factors such as physical plant 
layout, energy requirements, needed infrastructure, and workforce type 
and habits when considering technological feasibility. For purposes of 
evaluating economic feasibility, the EPA allows consideration of 
factors such as the capital costs, operating and maintenance costs, and 
cost effectiveness (i.e., cost per ton of pollutant reduced by a 
measure or technology) associated with the measure or control.\108\
---------------------------------------------------------------------------

    \108\ 40 CFR 51.1010(a)(3) and 81 FR 58010, 58041-58042.
---------------------------------------------------------------------------

    Once these analyses are complete, the state must use this 
information to develop enforceable control measures and submit them to 
the EPA for evaluation as SIP provisions to meet the basic requirements 
of CAA section 110 and any other applicable substantive provisions of 
the Act.
2. Summary of the State's Submission and the EPA's Evaluation and 
Proposed Action
    The control strategy in the SJV PM<INF>2.5</INF> Plan is based on 
ongoing emissions reductions from baseline control measures. As the 
term is used here, baseline measures are State and District regulations 
adopted prior to the development of the SJV PM<INF>2.5</INF> Plan that 
continue to achieve emissions reductions through the projected 2020 
attainment year and beyond. The 2018 PM<INF>2.5</INF> Plan describes 
these measures in Chapter 4,\109\ Appendix C (``Stationary Source 
Control Measure Analyses''), and Appendix D (``Mobile Source Control 
Measure Analyses''). Reductions from these baseline measures are 
incorporated into the projected baseline inventories and reductions 
from District measures are individually quantified in Appendix C.
---------------------------------------------------------------------------

    \109\ 2018 PM<INF>2.5</INF> Plan, Chapter 4, Table 4-2.
---------------------------------------------------------------------------

    The 2018 PM<INF>2.5</INF> Plan states that mobile sources emit over 
85 percent of the NO<INF>X</INF> in the San Joaquin Valley and that 
CARB has adopted and amended regulations to reduce public exposure to 
diesel particulate matter, which includes direct PM<INF>2.5</INF> and 
NO<INF>X</INF>, from ``fuel sources, freight transport sources like 
heavy-duty diesel trucks, transportation sources like passenger cars 
and buses, and non-road sources like large construction equipment.'' 
\110\
---------------------------------------------------------------------------

    \110\ 2018 PM<INF>2.5</INF> Plan, Chapter 4, 4-9. For CARB's 
BACM analysis for mobile source measures, see 2018 PM<INF>2.5</INF> 
Plan, Appendix D, including analyses for on-road light-duty vehicles 
and fuels (starting on page D-17), on-road heavy-duty vehicles and 
fuels (starting on page D-35), and non-road sources (starting on 
page D-64).
---------------------------------------------------------------------------

    Given the need for substantial emissions reductions from mobile and 
area sources to meet the NAAQS in California nonattainment areas, the 
State of California has developed stringent control measures for on-
road and non-road mobile sources and the fuels that power them. 
California has unique authority under CAA section 209 (subject to a 
waiver or authorization as applicable by the EPA) to adopt and 
implement new emissions standards for many categories of on-road 
vehicles and engines and new and in-use non-road vehicles and engines. 
The EPA has approved such mobile source regulations for which waiver 
authorizations have been issued as revisions to the California 
SIP.\111\
---------------------------------------------------------------------------

    \111\ For example, see 81 FR 39424 (June 16, 2016); 82 FR 14446 
(March 21, 2017); and 83 FR 23232 (May 18, 2018).
---------------------------------------------------------------------------

    CARB's mobile source program extends beyond regulations that are 
subject to the waiver or authorization process set forth in CAA section 
209 to

[[Page 38662]]

include standards and other requirements to control emissions from in-
use heavy-duty trucks and buses, gasoline and diesel fuel 
specifications, and many other types of mobile sources. Generally, 
these regulations have also been submitted and approved as revisions to 
the California SIP.\112\
---------------------------------------------------------------------------

    \112\ For example, see the EPA's approval of standards and other 
requirements to control emissions from in-use heavy-duty diesel 
trucks (77 FR 20308, April 4, 2012), and revisions to the California 
on-road reformulated gasoline and diesel fuel regulations (75 FR 
26653, May 12, 2010).
---------------------------------------------------------------------------

    As to stationary and area sources, the SJV PM<INF>2.5</INF> Plan 
states that stringent regulations adopted for prior attainment plans 
continue to reduce emissions of NO<INF>X</INF> and direct 
PM<INF>2.5</INF>.\113\ Specifically, Table 4-1 of the 2018 
PM<INF>2.5</INF> Plan identifies 33 District measures that limit 
NO<INF>X</INF> and direct PM<INF>2.5</INF> emissions from stationary 
and area sources.\114\
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    \113\ 2018 PM<INF>2.5</INF> Plan, Chapter 4, 4-3. For the 
District's BACM analysis for stationary and area source measures, 
see 2018 PM<INF>2.5</INF> Plan, Appendix C.
    \114\ Id. at Chapter 4, Table 4-1.
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a. Best Available Control Measures
    The State's BACM demonstration is presented in Appendix C 
(``Stationary Source Controls'') and Appendix D (``Mobile Source 
Control Measure Analyses'') of the 2018 PM<INF>2.5</INF> Plan. As 
discussed in section IV.A of this proposed rule, Appendix B 
(``Emissions Inventory'') of the 2018 PM<INF>2.5</INF> Plan contains 
the planning inventories for direct PM<INF>2.5</INF> and all 
PM<INF>2.5</INF> precursors (NO<INF>X,</INF> SO<INF>X,</INF> VOC, and 
ammonia) for the San Joaquin Valley nonattainment area together with 
documentation to support these inventories. Each inventory includes 
emissions from stationary, area, on-road, and non-road emission 
sources, and the State specifically identifies the condensable 
component of direct PM<INF>2.5</INF> for relevant stationary source and 
area source categories. As discussed in section IV.B of this proposed 
rule, the State concludes that the Plan should control emissions of 
PM<INF>2.5</INF> and NO<INF>X</INF> to reach attainment. Accordingly, 
the BACM and BACT evaluation in the Plan addresses potential controls 
for sources of those pollutants.
    For stationary and area sources, the District identifies the 
sources of direct PM<INF>2.5</INF> and NO<INF>X</INF> in the San 
Joaquin Valley that are subject to District emission control measures 
and provides its evaluation of these regulations for compliance with 
BACM requirements in Appendix C of the 2018 PM<INF>2.5</INF> Plan. As 
part of its process for identifying candidate BACM and considering the 
technical and economic feasibility of additional control measures, the 
District reviewed the EPA's guidance documents on BACM, additional 
guidance documents on control measures for direct PM<INF>2.5</INF> and 
NO<INF>X</INF> emission sources, and control measures implemented in 
other ozone and PM<INF>2.5</INF> nonattainment areas in California and 
other states.\115\ The District also provides an analysis of several 
SIP-approved VOC regulations that, according to the District, also 
provide ammonia co-benefits.\116\
---------------------------------------------------------------------------

    \115\ 2018 PM<INF>2.5</INF> Plan, Chapter 4, section 4.3.1.
    \116\ Id. at Appendix C., section C.25.
---------------------------------------------------------------------------

    For mobile sources, CARB identifies the sources of direct 
PM<INF>2.5</INF> and NO<INF>X</INF> in the San Joaquin Valley that are 
subject to the State's emission control measures and provides its 
evaluation of these regulations for compliance with BACM requirements 
in Appendix D of the 2018 PM<INF>2.5</INF> Plan. Appendix D describes 
CARB's process for determining BACM, including identification of the 
sources of direct PM<INF>2.5</INF> and NO<INF>X</INF> in the San 
Joaquin Valley, identification of potential control measures for such 
sources, assessment of the stringency and feasibility of the potential 
control measures, and adoption and implementation of feasible control 
measures.\117\ Appendix D of the 2018 PM<INF>2.5</INF> Plan also 
describes the current efforts of the eight local jurisdiction 
metropolitan planning organizations (MPOs) to implement cost-effective 
transportation control measures (TCMs) in the San Joaquin Valley.\118\
---------------------------------------------------------------------------

    \117\ Id. at Appendix D, Chapter II.
    \118\ Id. at Appendix D, D-127 and D-128.
---------------------------------------------------------------------------

    Because we are proposing to disapprove the comprehensive precursor 
demonstration in the SJV PM<INF>2.5</INF> Plan for purposes of the 1997 
annual PM<INF>2.5</INF> NAAQS, all precursors to the formation of 
PM<INF>2.5</INF> (i.e., NO<INF>X</INF>, ammonia, SO<INF>X</INF> and 
VOC) remain PM<INF>2.5</INF> plan precursors subject to control 
requirements under subpart 4 of part D, title I of the Act for purposes 
of the 1997 annual PM<INF>2.5</INF> NAAQS in the San Joaquin Valley. 
The SJV PM<INF>2.5</INF> Plan contains State and District control 
measures and related BACM analyses for sources of direct 
PM<INF>2.5</INF> and NO<INF>X</INF> in the San Joaquin Valley but does 
not contain such measures or analyses for sources of SO<INF>X</INF> or 
VOC emissions, given the State's assumption that these precursors would 
not be subject to controls. Furthermore, while the District provides an 
analysis of potential control of ammonia sources, the Plan does not 
identify any specific, enforceable requirement to reduce ammonia 
emissions in the area and does not demonstrate that the State or 
District adequately considered potential control measures for ammonia 
sources, given the State's assumption that ammonia would not be subject 
to controls. Without an approvable precursor demonstration, the SJV 
PM<INF>2.5</INF> Plan does not satisfy BACM and BACT requirements for 
sources of direct PM<INF>2.5</INF> and PM<INF>2.5</INF> plan precursors 
for purposes of the 1997 annual PM<INF>2.5</INF> NAAQS. We therefore 
propose to disapprove the BACM/BACT demonstration in the SJV 
PM<INF>2.5</INF> Plan for failure to meet the requirements of CAA 
section 189(b)(1)(B) and 40 CFR 51.1010 for the 1997 annual 
PM<INF>2.5</INF> NAAQS.
b. Five Percent Emission Reduction Requirement
    The SJV PM<INF>2.5</INF> Plan's demonstration of annual five 
percent reductions in NO<INF>X</INF> emissions is in section 5.2 of the 
2018 PM<INF>2.5</INF> Plan. As shown in Table 3, the demonstration uses 
the 2013 base year inventory as the starting point from which the five 
percent per year emission reductions are calculated and uses 2017 as 
the year from which the reductions start. The target required reduction 
in 2017 is five percent of the base year (2013) inventory, which is 
approximately 15.9 tpd of NO<INF>X</INF>, and the targets for 
subsequent years are additional reductions of five percent each year 
until the 2020 attainment year. The projected emissions inventories 
reflect NO<INF>X</INF> emissions reductions achieved by baseline 
control measures and the demonstration shows that these NO<INF>X</INF> 
emissions reductions are greater than the required five percent per 
year.

       Table 3--2017-2020 Annual Five Percent Emission Reductions Demonstration for the San Joaquin Valley
----------------------------------------------------------------------------------------------------------------
                                                                           CEPAM
                                        % Reduction   5% Target (tpd     inventory
                Year                  from 2013 base       NOX)         v1.05 (tpd             Meets 5%?
                                           year                            NOX)
----------------------------------------------------------------------------------------------------------------
2013 (base year)....................                                           317.3

[[Page 38663]]

 
2017................................               5           301.3           233.4  Yes.
2018................................              10           285.5           221.5  Yes.
2019................................              15           269.6           214.5  Yes.
2020................................              20           253.8           203.3  Yes.
----------------------------------------------------------------------------------------------------------------
Source: 2018 PM2.5 Plan, Table 5-2.

    The State's methodology for calculating the five percent emission 
reduction targets for the years 2017, 2018, 2019, and 2020 is 
consistent with CAA requirements as interpreted in the PM<INF>2.5</INF> 
SIP Requirements Rule, and the Plan shows that NO<INF>X</INF> emissions 
reductions from 2017 to 2020 are greater than the required five percent 
per year. However, the language in section 189(d) compels us to 
conclude that the five percent demonstration in the Plan does not meet 
that section's requirement for the 1997 annual PM<INF>2.5</INF> NAAQS. 
CAA section 189(d) requires that the plan provide for annual reductions 
of PM<INF>2.5</INF> or a PM<INF>2.5</INF> precursor of not less than 
five percent each year from the date of submission of the plan until 
the applicable attainment date approved by the EPA.\119\ The Plan 
submitted by California does not demonstrate reductions after 2020 
because it projects attainment of the 1997 annual PM<INF>2.5</INF> 
NAAQS by December 31, 2020. Because the EPA is proposing to disapprove 
the attainment demonstration, as discussed in section IV.D, based on 
ambient monitoring data for 2018-2020 indicating that the San Joaquin 
Valley did not attain the 1997 annual PM<INF>2.5</INF> NAAQS by the 
December 31, 2020 attainment date projected by the State in the SJV 
PM<INF>2.5</INF> Plan, December 31, 2020 is not the applicable 
attainment date for purposes of the 1997 annual PM<INF>2.5</INF> NAAQS 
in this area, and the Plan does not meet the requirement to demonstrate 
five percent reductions per year until attainment. Therefore, the EPA 
is proposing to disapprove the demonstration of the five percent annual 
emission reductions in the SJV PM<INF>2.5</INF> Plan for failure to 
meet the requirements of CAA section 189(d) and 40 CFR 51.1010(c) for 
the 1997 annual PM<INF>2.5</INF> NAAQS.
---------------------------------------------------------------------------

    \119\ Under 40 CFR 51.1000, the applicable attainment date is 
the latest statutory date by which an area is required to attain a 
particular PM<INF>2.5</INF> NAAQS or the attainment date approved by 
the EPA as part of an attainment plan for the area. For a Serious 
nonattainment area subject to the requirements of CAA section 
189(d), the EPA establishes the applicable attainment date in 
accordance with the provisions of CAA sections 179(d)(3) and 
172(a)(2). 81 FR 58010, 58103.
---------------------------------------------------------------------------

D. Attainment Demonstration and Modeling

1. Statutory and Regulatory Requirements
    Section 189(d) of the CAA requires a state with a Serious 
nonattainment area that failed to attain the NAAQS by the Serious area 
attainment date to submit a revised attainment demonstration as part of 
a new plan. The PM<INF>2.5</INF> SIP Requirements Rule explains that 
the same general requirements that apply to Moderate and Serious area 
plans under CAA sections 189(a) and 189(b) should apply to plans 
developed pursuant to CAA section 189(d)--i.e., the plan must include a 
demonstration (including air quality modeling) that the control 
strategy provides for attainment of the PM<INF>2.5</INF> NAAQS as 
expeditiously as practicable.\120\ For purposes of determining the 
attainment date that is as expeditious as practicable, the state must 
conduct future year modeling that takes into account emissions growth, 
known controls (including any controls that were previously determined 
to be RACM/RACT or BACM/BACT), the five percent per year emissions 
reductions required by CAA section 189(d), and any other emissions 
controls that are needed for expeditious attainment of the NAAQS.
---------------------------------------------------------------------------

    \120\ 81 FR 58010, 58102.
---------------------------------------------------------------------------

    The EPA's PM<INF>2.5</INF> modeling guidance \121\ (``Modeling 
Guidance'' and ``Modeling Guidance Update'') recommends that a 
photochemical model, such as the Comprehensive Air Quality Model with 
Extensions (CAMx) or Community Multiscale Air Quality Model (CMAQ), be 
used to simulate a base case, with meteorological and emissions inputs 
reflecting a base case year, to replicate concentrations monitored in 
that year. The model application to the base year undergoes a 
performance evaluation to ensure that it satisfactorily corroborates 
the concentrations monitored in that year. The model may then be used 
to simulate emissions occurring in other years required for a plan, 
namely the base year (which may differ from the base case year) and a 
future year.\122\ The modeled response to the emission changes between 
those years is used to calculate RRFs that are applied to the design 
value in the base year to estimate the projected design value in the 
future year for comparison against the NAAQS. Separate RRFs are 
estimated for each chemical species component of PM<INF>2.5</INF>, and 
for each quarter of the year, to reflect their differing responses to 
seasonal meteorological conditions and emissions. Because each species 
is handled separately, before applying an RRF, the base year design 
value must be speciated using available chemical species measurements--
that is, each day's measured PM<INF>2.5</INF> design value must be 
split into its species components. The Modeling Guidance provides 
additional detail on the recommended approach.\123\
---------------------------------------------------------------------------

    \121\ Memorandum dated November 29, 2018, from Richard Wayland, 
Air Quality Assessment Division, Office of Air Quality Planning and 
Standards, EPA, to Regional Air Division Directors, EPA, Subject: 
``Modeling Guidance for Demonstrating Air Quality Goals for Ozone, 
PM<INF>2.5</INF>, and Regional Haze,'' (``Modeling Guidance''), and 
memorandum dated June 28, 2011, from Tyler Fox, Air Quality Modeling 
Group, OAQPS, EPA, to Regional Air Program Managers, EPA, Subject: 
``Update to the 24 Hour PM<INF>2.5</INF> NAAQS Modeled Attainment 
Test,'' (``Modeling Guidance Update'').
    \122\ In this section, we use the terms ``base case,'' ``base 
year'' or ``baseline,'' and ``future year'' as described in section 
2.3 of the EPA's Modeling Guidance. The ``base case'' modeling 
simulates measured concentrations for a given time period, using 
emissions and meteorology for that same year. The modeling ``base 
year'' (which can be the same as the base case year) is the 
emissions starting point for the plan and for projections to the 
future year, both of which are modeled for the attainment 
demonstration. Modeling Guidance, 37-38.
    \123\ Modeling Guidance, section 4.4, ``What is the Modeled 
Attainment Tests for the Annual Average PM<INF>2.5</INF> NAAQS.''
---------------------------------------------------------------------------

2. Summary of the State's Submission
    As discussed in section IV.C, the SJV PM<INF>2.5</INF> Plan 
includes a modeled demonstration projecting that the San Joaquin Valley 
would attain the 1997

[[Page 38664]]

annual PM<INF>2.5</INF> NAAQS by December 31, 2020, based on ongoing 
emissions reductions from baseline control measures. CARB conducted 
photochemical modeling with the CMAQ model using inputs developed from 
routinely available meteorological and air quality data, as well as 
more detailed and extensive data from the DISCOVER-AQ field study 
conducted in January and February of 2013.\124\ The Plan's primary 
discussion of the photochemical modeling appears in Appendix K 
(``Modeling Attainment Demonstration'') of the 2018 PM<INF>2.5</INF> 
Plan. The State briefly summarizes the area's air quality problem in 
Chapter 2 (``Air Quality Challenges and Trends'') and the modeling 
results in Chapter 5.3 (``Attainment Demonstration and Modeling'') of 
the 2018 PM<INF>2.5</INF> Plan. The State provides a conceptual model 
of PM<INF>2.5</INF> formation in the San Joaquin Valley as part of the 
modeling protocol in Appendix L (``Modeling Protocol''). Appendix J 
(``Modeling Emission Inventory'') describes emission input preparation 
procedures. The State presents additional relevant information in 
Appendix C (``Weight of Evidence Analysis'') of the CARB Staff Report, 
which includes ambient trends and other data in support of the 
attainment demonstration.
---------------------------------------------------------------------------

    \124\ NASA, ``Deriving Information on Surface conditions from 
COlumn and VERtically Resolved Observations Relevant to Air 
Quality,'' available at https://www.nasa.gov/mission_pages/discover-aq/index.html.
---------------------------------------------------------------------------

    CARB's air quality modeling approach investigated the many inter-
connected facets of modeling ambient PM<INF>2.5</INF> in the San 
Joaquin Valley, including model input preparation, model performance 
evaluation, use of the model output for the numerical NAAQS attainment 
test, and modeling documentation. Specifically, this required the 
development and evaluation of a conceptual model, modeling protocol, 
episode (i.e., base year) selection, modeling domain, CMAQ model 
selection, initial and boundary condition procedures, meteorological 
model choice and performance, modeling emissions inventory preparation 
procedures, model performance, attainment test procedure, adjustments 
to baseline air quality for modeling, the 2020 attainment test, and an 
unmonitored area analysis. These analyses are generally consistent with 
the EPA's recommendations in the Modeling Guidance.
    The model performance evaluation in Appendix K includes statistical 
and graphical measures of model performance. The magnitude and timing 
of predicted concentrations of total PM<INF>2.5</INF>, as well as of 
its ammonium and nitrate components, generally match the occurrence of 
elevated PM<INF>2.5</INF> levels in the measured observations. A 
comparison to other recent modeling efforts shows good model 
performance on bias, error, and correlation with measurements, for 
total PM<INF>2.5</INF> and for most of its chemical components. The 
Weight of Evidence Analysis shows the downward trend in NO<INF>X</INF> 
emissions along with a 24 to 44 percent decrease in annual 
PM<INF>2.5</INF> design values between 1999 and 2017.\125\ The analysis 
also shows decreases in daily PM<INF>2.5</INF> concentrations during 
winter, and in the frequency of high PM<INF>2.5</INF> concentrations 
generally.\126\ Available ambient air quality data show that total 
PM<INF>2.5</INF> and ammonium nitrate concentrations have declined over 
the 2004-2017 period, despite some increases from time to time.\127\ 
These trends show that there has been an improvement in air quality due 
to emissions reductions in the San Joaquin Valley.
---------------------------------------------------------------------------

    \125\ Weight of Evidence Analysis, 26-27, Figure 12, and Figure 
24.
    \126\ Id. at Figure 16 and Figure 17.
    \127\ Id. at Figure 21.
---------------------------------------------------------------------------

    The State conducted three CMAQ \128\ simulations: (1) A 2013 base 
year simulation to demonstrate that the model reasonably reproduced the 
observed PM<INF>2.5</INF> concentrations in the San Joaquin Valley; (2) 
a 2013 baseline year simulation that was the same as the 2013 base year 
simulation but excluded exceptional event emissions, such as wildfire 
emissions; and (3) a 2020 future year simulation that reflects 
projected emissions growth and reductions due to controls that have 
already been adopted and implemented.
---------------------------------------------------------------------------

    \128\ CMAQ Version 5.0.2.
---------------------------------------------------------------------------

    Table 4 shows the 2013 base year and 2020 projected future year 
annual PM<INF>2.5</INF> design values at monitoring sites in the San 
Joaquin Valley. The highest 2020 projected design value is 14.6 [mu]g/m 
\3\ at the Bakersfield--California monitoring site, which is below the 
15.0 [mu]g/m \3\ level of the 1997 annual PM<INF>2.5</INF> NAAQS.

Table 4--Projected Future Annual PM2.5 Design Values at Monitoring Sites
                        in the San Joaquin Valley
                              [[mu]g/m\3\]
------------------------------------------------------------------------
                                                               2020
             Monitoring site                 2013 Base       Projected
                                           design value    design value
------------------------------------------------------------------------
Bakersfield--California.................            17.2            14.6
Fresno--Garland.........................            16.9            14.2
Hanford.................................            16.5            13.3
Fresno--Hamilton & Winery...............            16.2            13.5
Clovis..................................            16.1            13.4
Visalia.................................            16.0            13.5
Bakersfield--Planz......................            15.0            12.4
Madera..................................            14.9            12.5
Turlock.................................            14.2            11.9
Modesto.................................            13.1            11.4
Merced-M. Street........................            13.1            10.9
Stockton................................            13.0            11.0
Merced--S Coffee........................            11.0             9.3
Manteca.................................            10.1             8.7
Tranquility.............................             7.7             6.4
------------------------------------------------------------------------
Source: 2018 PM2.5 Plan, Table 5-4.


[[Page 38665]]

3. The EPA's Evaluation and Proposed Action
    The EPA has reviewed monitoring data recorded at air quality 
monitors throughout the San Joaquin Valley PM<INF>2.5</INF> 
nonattainment area to consider whether the area attained the 1997 
annual PM<INF>2.5</INF> NAAQS by the December 31, 2020 attainment date 
projected in the SJV PM<INF>2.5</INF> Plan. We based our review on 
preliminary but complete and quality-assured ambient air monitoring 
data recorded during the three years preceding the State's identified 
attainment date (2018-2020).\129\ The EPA has found that the 
PM<INF>2.5</INF> monitoring network in the San Joaquin Valley currently 
meets or exceeds the requirements for the minimum number of monitoring 
sites designated as State and Local Air Monitoring Stations (SLAMS) for 
PM<INF>2.5</INF> and that CARB's and the District's annual network 
plans meet the applicable requirements in 40 CFR part 58.\130\
---------------------------------------------------------------------------

    \129\ At the time of the EPA's review, the State had not yet 
certified the 2020 ambient air monitoring data. We understand that 
the State is working to certify the data and anticipate that the 
2020 data will be certified prior to our final action. We do not 
expect the certified data to differ significantly from the data 
reflected in this proposal.
    \130\ Letter dated October 26, 2020, from Gwen Yoshimura, 
Manager, EPA Region 9, Air Quality Analysis Office, to Jon Klassen, 
Director of Strategies and Incentives, SJVUAPCD, and letter dated 
November 5, 2020, from Gwen Yoshimura, Manager, EPA Region 9, Air 
Quality Analysis Office, to Ravi Ramalingam, Chief, Consumer 
Products and Air Quality Assessment Branch, CARB.
---------------------------------------------------------------------------

    Table 5 shows the annual arithmetic means and preliminary annual 
PM<INF>2.5</INF> design values at each of the 18 SLAMS monitoring sites 
within the San Joaquin Valley nonattainment area for the most recent 
three-year period (2018-2020). The data show that the annual design 
value for the 2018-2020 period ranged from 9.5 to 17.6 [mu]g/m \3\ 
across the area at monitors with valid design values, and that the 
valid design values exceeded 15.0 [mu]g/m \3\ (i.e., the level of the 
1997 annual PM<INF>2.5</INF> NAAQS) at eight of the monitoring sites, 
indicating that the area did not attain the 1997 annual 
PM<INF>2.5</INF> NAAQS by the projected December 31, 2020 attainment 
date.
    As discussed in section IV.D.2, CARB's Weight of Evidence Analysis 
shows a long-term downward trend in annual PM<INF>2.5</INF> design 
values through 2017, the latest year prior to development of the SJV 
PM<INF>2.5</INF> Plan for which air quality data were available. As 
described in the Weight of Evidence Analysis, the San Joaquin Valley 
has shown a general downward trend in measured PM<INF>2.5</INF> 
concentrations despite the effects of extensive wildfires in 2008 and 
unusual meteorological conditions during the 2013/2014 winter that 
resulted in higher concentrations during those periods. Similarly, the 
San Joaquin Valley area may have experienced higher than normal 
PM<INF>2.5</INF> concentrations in 2018 and 2020 due to wildfires in 
the surrounding areas during the summer and fall months. Table 5 shows 
that concentrations at all 17 monitors in the San Joaquin Valley area 
with data spanning 2018 to 2020 are significantly higher in 2018 and 
2020 relative to concentrations in 2019, possibly due to the wildfires 
in those years.

                               Table 5--2018-2020 Annual PM2.5 Design Values for the San Joaquin Valley Nonattainment Area
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                Annual arithmetic mean ([mu]g/m\3\)          2018-2020
                                                                                         ------------------------------------------------ Annual  design
                  County                        General location site         AQS ID                                                      values ([mu]g/
                                                                                               2018            2019            2020          m\3\) \a\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Fresno....................................  Fresno--Pacific.............     06-019-5025            17.1            11.2            18.7            15.7
                                            Fresno--Garland.............     06-019-0011            16.2            11.1            19.2            15.5
                                            Fresno--Foundry.............     06-019-2016             Inc             Inc            20.3        \b\ 20.3
                                                                                                                                                   (Inv)
                                            Clovis......................     06-019-5001            14.3            10.3            18.4            14.4
                                                                                                                   (Inc)                           (Inv)
                                            Tranquility.................     06-019-2009            11.1             5.8            11.5             9.5
Kern......................................  Bakersfield--Planz Road.....     06-029-0016            19.4            13.0            20.3            17.6
                                            Bakersfield--California Ave.     06-029-0014            17.7            11.9            19.7            16.4
                                            Bakersfield--Golden State        06-029-0010            18.1            12.4            20.0            16.8
                                             Highway.
Kings.....................................  Corcoran....................     06-031-0004            17.2            12.1            19.5            16.3
                                            Hanford.....................     06-031-1004            17.7            12.2            19.9            16.6
Madera....................................  Madera--Avenue 14...........     06-039-2010            14.0             9.7            16.9            13.5
Merced....................................  Merced--M Street............     06-047-2510            14.2             9.6            15.5            13.1
                                            Merced--Coffee..............     06-047-0003            15.1             9.1            14.7            13.0
San Joaquin...............................  Stockton....................     06-077-1002            17.6             9.3            14.4            13.8
                                            Manteca.....................     06-077-2010            13.4             8.3            14.8            12.2
                                                                                                                   (Inc)                           (Inv)
Stanislaus................................  Modesto.....................     06-099-0005            15.2             7.7            14.5            12.5
                                            Turlock.....................     06-099-0006            17.2            10.7            15.5            14.5
Tulare....................................  Visalia.....................     06-107-2002            17.3            12.9            19.7            16.7
--------------------------------------------------------------------------------------------------------------------------------------------------------
Source: EPA, Preliminary 2020 AQS Design Value Report, AMP480, accessed June 15, 2021.
Notes: Inc = Incomplete data. Inv = Invalid design value due to incomplete data. Design values shown in bold type do not meet the 1997 annual PM2.5
  NAAQS.
\a\ This preliminary design value includes all available data; no data flagged for exceptional events have been excluded.
\b\ The preliminary 2018-2020 design value at Fresno-Foundry (AQS ID: 06-019-2016) is based on concentration data from January 1, 2020 to December 31,
  2020. The site began operation in 2020; therefore, data from January 1, 2018 to December 31, 2019 are not available. Based on 40 CFR part 50, Appendix
  N, section 4.1(b), three years of valid annual means are required to produce a valid annual PM2.5 NAAQS design value. Thus, the Fresno-Foundry 2018-
  2020 preliminary design value is considered invalid.

    Under 40 CFR part 50, appendix N, because the 2018-2020 preliminary 
design value exceeded the 15.0 [mu]g/m \3\ level of the 1997 annual 
PM<INF>2.5</INF> NAAQS, the San Joaquin Valley area did not attain the 
1997 annual PM<INF>2.5</INF> NAAQS by December 31, 2020, as projected 
in the SJV PM<INF>2.5</INF> Plan. Therefore, the EPA is proposing to 
disapprove the attainment

[[Page 38666]]

demonstration in the SJV PM<INF>2.5</INF> Plan for the 1997 annual 
PM<INF>2.5</INF> NAAQS for failure to meet the requirements of CAA 
sections 189(d) and 179(d) and 40 CFR 51.1011(b). Because our proposal 
is based on ambient monitoring data clearly indicating that the Plan 
was insufficient to achieve attainment of the 1997 annual 
PM<INF>2.5</INF> NAAQS by the December 31, 2020 attainment date, we do 
not provide a full evaluation of the attainment demonstration analyses 
for these NAAQS at this time.

E. Reasonable Further Progress and Quantitative Milestones

1. Statutory and Regulatory Requirements
    CAA section 172(c)(2) provides that all nonattainment area plans 
shall require RFP toward attainment. In addition, CAA section 189(c) 
requires that all PM<INF>2.5</INF> nonattainment area SIPs include 
quantitative milestones to be achieved every three years until the area 
is redesignated to attainment and that demonstrate RFP. Section 171(l) 
of the Act defines RFP as ``such annual incremental reductions in 
emissions of the relevant air pollutant as are required by [Part D] or 
may reasonably be required by the Administrator for the purpose of 
ensuring attainment of the applicable [NAAQS] by the applicable date.'' 
Neither subpart 1 nor subpart 4 of part D, title I of the Act requires 
that states achieve a set percentage of emission reductions in any 
given year for purposes of satisfying the RFP requirement. For purposes 
of the PM<INF>2.5</INF> NAAQS, the EPA has interpreted the RFP 
requirement to require that the nonattainment area plans show annual 
incremental emission reductions sufficient to maintain generally linear 
progress toward attainment by the applicable deadline.\131\
---------------------------------------------------------------------------

    \131\ General Preamble Addendum, 42015.
---------------------------------------------------------------------------

    Attainment plans for PM<INF>2.5</INF> nonattainment areas should 
include detailed schedules for compliance with emission regulations in 
the area and provide corresponding annual emission reductions to be 
achieved by each milestone in the schedule.\132\ In reviewing an 
attainment plan under subpart 4, the EPA considers whether the annual 
incremental emission reductions to be achieved are reasonable in light 
of the statutory objective of timely attainment. Although early 
implementation of the most cost-effective control measures is often 
appropriate, states should consider both cost-effectiveness and 
pollution reduction effectiveness when developing implementation 
schedules for control measures and may implement measures that are more 
effective at reducing PM<INF>2.5</INF> earlier to provide greater 
public health benefits.\133\
---------------------------------------------------------------------------

    \132\ Id. at 42016.
    \133\ Id.
---------------------------------------------------------------------------

    The PM<INF>2.5</INF> SIP Requirements Rule establishes specific 
regulatory requirements for purposes of satisfying the Act's RFP 
requirements and provides related guidance in the preamble to the rule. 
Specifically, under the PM<INF>2.5</INF> SIP Requirements Rule, each 
PM<INF>2.5</INF> attainment plan must contain an RFP analysis that 
includes, at minimum, the following four components: (1) An 
implementation schedule for control measures; (2) RFP projected 
emissions for direct PM<INF>2.5</INF> and all PM<INF>2.5</INF> plan 
precursors for each applicable milestone year, based on the anticipated 
control measure implementation schedule; (3) a demonstration that the 
control strategy and implementation schedule will achieve reasonable 
progress toward attainment between the base year and the attainment 
year; and (4) a demonstration that by the end of the calendar year for 
each milestone date for the area, pollutant emissions will be at levels 
that reflect either generally linear progress or stepwise progress in 
reducing emissions on an annual basis between the base year and the 
attainment year.\134\ Additionally, states should estimate the RFP 
projected emissions for each quantitative milestone year by sector on a 
pollutant-by-pollutant basis.\135\
---------------------------------------------------------------------------

    \134\ 40 CFR 51.1012(a).
    \135\ 81 FR 58010, 58056.
---------------------------------------------------------------------------

    Section 189(c) of the Act requires that PM<INF>2.5</INF> attainment 
plans include quantitative milestones that demonstrate RFP. The purpose 
of the quantitative milestones is to allow periodic evaluation of the 
area's progress towards attainment of the NAAQS consistent with RFP 
requirements. Because RFP is an annual emission reduction requirement 
and the quantitative milestones are to be achieved every three years, 
when a state demonstrates compliance with the quantitative milestone 
requirement, it should also demonstrate that RFP has been achieved 
during each of the relevant three years. Quantitative milestones should 
provide an objective means to evaluate progress toward attainment 
meaningfully, e.g., through imposition of emission controls in the 
attainment plan and the requirement to quantify those required emission 
reductions. The CAA also requires states to submit milestone reports 
(due 90 days after each milestone), and these reports should include 
calculations and any assumptions made by the state concerning how RFP 
has been met, e.g., through quantification of emission reductions to 
date.\136\
---------------------------------------------------------------------------

    \136\ General Preamble Addendum, 42016-42017.
---------------------------------------------------------------------------

    The CAA does not specify the starting point for counting the three-
year periods for quantitative milestones under CAA section 189(c). In 
the General Preamble and General Preamble Addendum, the EPA interpreted 
the CAA to require that the starting point for the first three-year 
period be the due date for the Moderate area plan submission.\137\ In 
keeping with this historical approach, the EPA established December 31, 
2014, the deadline that the EPA established for a state's submission of 
any additional attainment-related SIP elements necessary to satisfy the 
subpart 4 Moderate area requirements for the 1997 PM<INF>2.5</INF> 
NAAQS, as the starting point for the first three-year period under CAA 
section 189(c) for the 1997 PM<INF>2.5</INF> NAAQS in the San Joaquin 
Valley.\138\
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    \137\ General Preamble, 13539, and General Preamble Addendum, 
42016.
    \138\ 79 FR 31566 (June 2, 2014) (final rule establishing 
subpart 4 moderate area classifications and deadline for related SIP 
submissions). Although this final rule did not affect any action 
that the EPA had previously taken under CAA section 110(k) on a SIP 
for a PM<INF>2.5</INF> nonattainment area, the EPA noted that states 
may need to submit additional SIP elements to fully comply with the 
applicable requirements of subpart 4, even for areas with previously 
approved PM<INF>2.5</INF> attainment plans, and that the deadline 
for any such additional plan submissions was December 31, 2014. Id. 
at 31569.
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    Under the PM<INF>2.5</INF> SIP Requirements Rule, each attainment 
plan submission for an area designated nonattainment for the 1997 
PM<INF>2.5</INF> NAAQS before January 15, 2015, must contain 
quantitative milestones to be achieved no later than three years after 
December 31, 2014, and every three years thereafter until the milestone 
date that falls within three years after the applicable attainment 
date.\139\ If the area fails to attain, this post-attainment date 
milestone provides the EPA with the tools necessary to monitor the 
area's continued progress toward attainment while the state develops a 
new attainment plan.\140\ Quantitative milestones must provide for 
objective evaluation of RFP toward timely attainment of the 
PM<INF>2.5</INF> NAAQS in the area and include, at minimum, a metric 
for tracking progress achieved in implementing SIP control measures, 
including BACM and BACT, by each milestone date.\141\
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    \139\ 40 CFR 51.1013(a)(4).
    \140\ 81 FR 58010, 58064.
    \141\ Id. at 58064 and 58092.
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    Because the EPA designated the San Joaquin Valley area as 
nonattainment for the 1997 annual PM<INF>2.5</INF> NAAQS effective

[[Page 38667]]

April 5, 2005,\142\ the plan for this area must contain quantitative 
milestones to be achieved no later than three years after December 31, 
2014 (i.e., by December 31, 2017), and every three years thereafter 
until the milestone date that falls within three years after the 
applicable attainment date.\143\
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    \142\ 70 FR 944 (January 5, 2005).
    \143\ 40 CFR 51.1013(a)(4).
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2. Summary of the State's Submission
    Appendix H (``RFP, Quantitative Milestones, and Contingency'') of 
the 2018 PM<INF>2.5</INF> Plan contains the State's RFP demonstration 
and quantitative milestones for the 1997 annual PM<INF>2.5</INF> 
NAAQS,\144\ and the Valley State SIP Strategy contains the control 
measure commitments that CARB has identified as mobile source 
quantitative milestones for the 2020 milestone date.\145\ Given the 
State's conclusions that ammonia, SO<INF>X</INF>, and VOC emissions do 
not contribute significantly to PM<INF>2.5</INF> levels that exceed the 
1997 annual PM<INF>2.5</INF> NAAQS in the San Joaquin Valley, as 
discussed in section IV.B of this proposed rule, the RFP demonstration 
provided by the State addresses emissions of direct PM<INF>2.5</INF> 
and NO<INF>X</INF>.\146\ Similarly, the State developed quantitative 
milestones based upon implementation of control strategy measures in 
the adopted SIP and in the SJV PM<INF>2.5</INF> Plan that achieve 
reductions in emissions of direct PM<INF>2.5</INF> and 
NO<INF>X</INF>.\147\ For the 1997 annual PM<INF>2.5</INF> NAAQS, the 
RFP demonstration in the Plan shows generally linear progress toward 
attainment.
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    \144\ As discussed in footnote 32, all references to Appendix H 
in this proposed rule are to the revised version submitted on 
February 11, 2020, which replaces the version submitted with the 
2018 PM<INF>2.5</INF> Plan on May 10, 2019.
    \145\ Valley State SIP Strategy, Table 7 (identifying State 
measures scheduled for action between 2017 and 2020, inter alia) and 
CARB Resolution 18-49, ``San Joaquin Valley Supplement to the 2016 
State Strategy for the State Implementation Plan'' (October 25, 
2018), 5 (adopting State commitment to begin public processes and 
propose for Board consideration the list of proposed SIP measures 
outlined in the Valley State SIP Strategy and included in Attachment 
A, according to the schedule set forth therein).
    \146\ 2018 PM<INF>2.5</INF> Plan, Appendix H, H-1.
    \147\ Id. at H-18 and H-19 (District milestones), and H-21 and 
H-22 (State milestones).
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    We describe the RFP demonstration and quantitative milestones in 
the SJV PM<INF>2.5</INF> Plan in greater detail below.
Reasonable Further Progress
    The State addresses the RFP and quantitative milestone requirements 
in Appendix H to the 2018 PM<INF>2.5</INF> Plan submitted in February 
2020. The Plan estimates that emissions of direct PM<INF>2.5</INF> and 
NO<INF>X</INF> will generally decline from the 2013 base year to the 
projected 2020 attainment year, and beyond to the 2023 post-attainment 
quantitative milestone year. The Plan's emissions inventory shows that 
direct PM<INF>2.5</INF> and NO<INF>X</INF> are emitted by a large 
number and range of sources in the San Joaquin Valley. Table H-2 in 
Appendix H contains an anticipated implementation schedule for District 
regulatory control measures and Table 4-8 in Chapter 4 of the 2018 
PM<INF>2.5</INF> Plan contains an anticipated implementation schedule 
for CARB control measures in the San Joaquin Valley. Table H-5 in 
Appendix H contains projected emissions for each quantitative milestone 
year. These emission levels reflect baseline emission projections 
through the 2023 post-attainment milestone year.\148\
---------------------------------------------------------------------------

    \148\ Id. at tables H-3 to H-5.
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    The SJV PM<INF>2.5</INF> Plan identifies emission reductions needed 
for attainment of the 1997 annual PM<INF>2.5</INF> NAAQS by 2020,\149\ 
and identifies San Joaquin Valley's progress toward attainment in each 
milestone year.\150\ The State and District set RFP targets for each of 
the quantitative milestone years as shown in Table H-8 of Appendix H of 
the 2018 PM<INF>2.5</INF> Plan.
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    \149\ Id. at Table H-6.
    \150\ Id. at Table H-7.
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    According to the Plan, reductions in both direct PM<INF>2.5</INF> 
and NO<INF>X</INF> emissions from 2013 base year levels result in 
emission levels consistent with attainment in the 2020 attainment year. 
Based on these analyses, the State and District conclude that the 
adopted control strategy is adequate to meet the RFP requirement for 
the 1997 annual PM<INF>2.5</INF> NAAQS.
Quantitative Milestones
    Appendix H of the 2018 PM<INF>2.5</INF> Plan identifies the 
milestone dates of December 31, 2017, December 31, 2020, and December 
31, 2023, for the 1997 PM<INF>2.5</INF> NAAQS.\151\ Appendix H also 
identifies target emission levels to meet the RFP requirement for 
direct PM<INF>2.5</INF> and NO<INF>X</INF> emissions for each of these 
milestone years,\152\ and State and District control measures that will 
achieve emission reductions in the years leading up to each of the 
milestones, in accordance with the control strategy in the Plan.\153\
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    \151\ Id. at Table H-12.
    \152\ Id. at Table H-8.
    \153\ Id. at H-18 and H-19 (District milestones), and H-21 and 
H-22 (State milestones).
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    The Plan includes quantitative milestones for mobile, stationary, 
and area sources. For mobile sources, CARB has developed quantitative 
milestones that provide for an evaluation of RFP based on the 
implementation of specific control measures by the relevant three-year 
milestones. For each quantitative milestone year, the Plan provides for 
evaluating RFP by tracking State and District implementation of 
regulatory measures and SIP commitments during the three-year period 
leading to each milestone date, consistent with the control strategy in 
the SJV PM<INF>2.5</INF> Plan.\154\ The identified regulatory measures 
include State measures for light-duty vehicles and non-road vehicles 
and several District measures for stationary and area sources.\155\
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    \154\ Id. We note that the District's identified quantitative 
milestones for 2023 appear to contain a typographical error, as they 
include a District report on ``[t]he status of SIP measures adopted 
between 2017 and 2020 as per the schedule included in the adopted 
Plan.'' Id. at H-18 and H-19. We understand that the District 
intended to refer here to the status of SIP measures adopted between 
2020 and 2023, consistent with the schedule in the 2018 
PM<INF>2.5</INF> Plan.
    \155\ Id. at H-18 and H-19 (District milestones), and H-21 and 
H-22 (State milestones).
---------------------------------------------------------------------------

    CARB submitted its 2017 Quantitative Milestone Report for the San 
Joaquin Valley to the EPA on December 20, 2018.\156\ The report 
includes a certification that CARB and the District met the 2017 
quantitative milestones identified in the SJV PM<INF>2.5</INF> Plan for 
the 1997 PM<INF>2.5</INF> NAAQS and discusses the State's and 
District's progress on implementing the three CARB measures and six 
District measures identified in Appendix H as quantitative milestones 
for the 2017 milestone year. On February 15, 2021, the EPA determined 
that the 2017 Quantitative Milestone Report was adequate.\157\ In our 
evaluation of the 2017 Quantitative Milestone Report, we found that the 
control measures in the Plan are in effect, consistent with the RFP 
demonstration in the SJV PM<INF>2.5</INF> Plan for the 1997 annual 
PM<INF>2.5</INF> NAAQS, but we noted that the determination of adequacy 
did not constitute approval of any component of the SJV 
PM<INF>2.5</INF> Plan.\158\
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    \156\ Letter dated December 20, 2018, from Richard W. Corey, 
Executive Officer, CARB, to Michael Stoker, Regional Administrator, 
EPA Region 9, with attachment ``2017 Quantitative Milestone Report 
for the 1997 and 2006 NAAQS.''
    \157\ Letter dated February 15, 2021, from Deborah Jordan, 
Acting Regional Administrator, EPA Region IX, to Richard W. Corey, 
Executive Officer, CARB, with enclosure titled ``EPA Evaluation of 
2017 Quantitative Milestone Report.''
    \158\ Id.
---------------------------------------------------------------------------

3. The EPA's Evaluation and Proposed Action
    As discussed in section IV.D, we are proposing to disapprove the 
attainment demonstration for the 1997 annual PM<INF>2.5</INF> NAAQS in 
the SJV PM<INF>2.5</INF> Plan because the area did not attain by the 
State's projected attainment date, which was December 31, 2020. As a 
result, the RFP

[[Page 38668]]

demonstration in the Plan does not achieve the statutory purpose of RFP 
to ``ensure attainment'' under CAA section 171(l) and the quantitative 
milestones do not ``demonstrate [RFP] toward attainment by the 
applicable date'' under CAA section 189(c). We are, therefore, 
proposing to disapprove the RFP and quantitative milestone elements of 
the SJV PM<INF>2.5</INF> Plan for the 1997 annual PM<INF>2.5</INF> 
NAAQS for failure to meet the requirements of CAA sections 172(c)(2), 
171(1), and 189(c) and 40 CFR 51.1012 and 51.1013.

F. Contingency Measures

1. Requirements for Contingency Measures
    Under CAA section 172(c)(9), each state required to make a 
nonattainment plan SIP submission must include, in such plan, 
contingency measures to be implemented if an area fails to meet RFP 
(``RFP contingency measures'') or fails to attain the NAAQS by the 
applicable attainment date (``attainment contingency measures''). Under 
the PM<INF>2.5</INF> SIP Requirements Rule, states must include 
contingency measures that will be implemented following a determination 
by the EPA that the state has failed: (1) To meet any RFP requirement 
in the approved SIP; (2) to meet any quantitative milestone in the 
approved SIP; (3) to submit a required quantitative milestone report; 
or (4) to attain the applicable PM<INF>2.5</INF> NAAQS by the 
applicable attainment date.\159\ Contingency measures must be fully 
adopted rules or control measures that are ready to be implemented 
quickly upon failure to meet RFP or failure of the area to meet the 
relevant NAAQS by the applicable attainment date.\160\
---------------------------------------------------------------------------

    \159\ 40 CFR 51.1014(a).
    \160\ 81 FR 58010, 58066 and General Preamble Addendum, 42015.
---------------------------------------------------------------------------

    The purpose of contingency measures is to continue progress in 
reducing emissions while a state revises its SIP to meet the missed RFP 
requirement or to correct ongoing nonattainment. Neither the CAA nor 
the EPA's implementing regulations establish a specific level of 
emission reductions that implementation of contingency measures must 
achieve, but the EPA recommends that contingency measures should 
provide for emission reductions equivalent to approximately one year of 
reductions needed for RFP in the nonattainment area at issue, 
calculated as the overall level of reductions needed to demonstrate 
attainment divided by the number of years from the base year to the 
attainment year. In general, we expect all actions needed to effect 
full implementation of the measures to occur within 60 days after the 
EPA notifies the state of a failure to meet RFP or to attain.\161\
---------------------------------------------------------------------------

    \161\ 81 FR 58010, 58066. See also General Preamble, 13512, 
13543-13544, and General Preamble Addendum, 42014-42015.
---------------------------------------------------------------------------

    To satisfy the requirements of 40 CFR 51.1014, the contingency 
measures adopted as part of a PM<INF>2.5</INF> attainment plan must 
consist of control measures for the area that are not otherwise 
required to meet other nonattainment plan requirements (e.g., to meet 
RACM/RACT requirements) and must specify the timeframe within which 
their requirements become effective following any of the EPA 
determinations specified in 40 CFR 51.1014(a). In a 2016 decision 
called Bahr v. EPA (``Bahr''),\162\ the Ninth Circuit Court of Appeals 
rejected the EPA's interpretation of CAA section 172(c)(9) to allow 
approval of already-implemented control measures as contingency 
measures. In Bahr, the Ninth Circuit concluded that contingency 
measures must be measures that are triggered and implemented only after 
the EPA determines that an area failed to meet RFP requirements or to 
attain by the applicable attainment date. Thus, within the geographic 
jurisdiction of the Ninth Circuit, already implemented measures cannot 
serve as contingency measures under CAA section 172(c)(9). To comply 
with section 172(c)(9), a state must develop, adopt, and submit a 
contingency measure to be triggered upon a failure to meet an RFP 
milestone, failure to meet a quantitative milestone requirement, or 
failure to attain the NAAQS by the applicable attainment date.
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    \162\ Bahr v. EPA, 836 F.3d 1218, 1235-1237 (9th Cir. 2016).
---------------------------------------------------------------------------

2. Summary of the State's Submission
    The SJV PM<INF>2.5</INF> Plan addresses the contingency measure 
requirement for the 1997 annual PM<INF>2.5</INF> NAAQS in section 5.6 
and Appendix H (specifically, section H.3 (``Contingency Measures'')) 
of the 2018 PM<INF>2.5</INF> Plan. The Plan relies on revisions to the 
District's wood-burning rule (Rule 4901) and refers to a SIP revision 
submitted by CARB on October 23, 2017, titled ``State Implementation 
Plan Attainment Contingency Measures for the San Joaquin Valley 15 
[mu]g/m \3\ Annual PM<INF>2.5</INF> NAAQS'' (``2017 Contingency Measure 
SIP'').\163\ On March 19, 2021, CARB withdrew the 2017 Contingency 
Measure SIP submission.\164\ Therefore, we are not evaluating the 2017 
Contingency Measure SIP as part of this action.
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    \163\ Letter dated October 23, 2017, from Richard W. Corey, 
Executive Officer, CARB, to Alexis Strauss, Acting Regional 
Administrator, EPA Region 9.
    \164\ Letter dated March 19, 2021, from Richard W. Corey, 
Executive Officer, CARB, to Deborah Jordan, Acting Regional 
Administrator, EPA Region 9, transmitting CARB Executive Order S-21-
004.
---------------------------------------------------------------------------

    With respect to the District contingency measure, the 2018 
PM<INF>2.5</INF> Plan states that the District will amend Rule 4901 to 
include a requirement that would be triggered upon a determination by 
the EPA that the San Joaquin Valley failed to meet a regulatory 
requirement necessitating implementation of a contingency measure.\165\ 
As discussed in section II.C, the District adopted amendments to Rule 
4901 on June 20, 2019, including a contingency measure in section 5.7.3 
of the amended rule. In the EPA's July 22, 2020 final action to approve 
Rule 4901, as amended June 20, 2019, we did not evaluate section 5.7.3 
of the amended rule for compliance with CAA requirements for 
contingency measures.\166\ We are now evaluating section 5.7.3 of Rule 
4901 for compliance with the requirements for contingency measures for 
purposes of the 1997 annual PM<INF>2.5</INF> NAAQS.
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    \165\ 2018 PM<INF>2.5</INF> Plan, Appendix H, H-25.
    \166\ 85 FR 44206 (July 22, 2020) (final approval of Rule 4901); 
85 FR 1131, 1132-1133 (January 9, 2020) (proposed approval of Rule 
4901).
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    Rule 4901 is designed to limit emissions generated by the use of 
wood burning fireplaces, wood burning heaters, and outdoor wood burning 
devices. The rule establishes requirements for the sale/transfer, 
operation, and installation of wood burning devices and for advertising 
the sale of seasoned wood consistent with a moisture content limit 
within the San Joaquin Valley. The rule includes a two-tiered, episodic 
wood burning curtailment requirement that applies during four winter 
months, November through February. During a level one episodic wood 
burning curtailment, section 5.7.1 prohibits any person from operating 
a wood burning fireplace or unregistered wood burning heater, but 
permits the use of a properly operated wood burning heater that meets 
certification requirements and has a current registration with the 
District. Sections 5.9 through 5.11 impose specific registration 
requirements on any person operating a wood burning fireplace or wood 
burning heater and section 5.12 imposes specific certification 
requirements on wood burning heater professionals. During a level two 
episodic wood burning curtailment, operation of any wood burning device 
is prohibited by section 5.7.2.
    Prior to the 2019-2020 wood burning season, the District imposed a 
level one

[[Page 38669]]

curtailment when the PM<INF>2.5</INF> concentration was forecasted to 
be between 20 [mu]g/m \3\ and 65 [mu]g/m \3\ and imposed a level two 
curtailment when the PM<INF>2.5</INF> concentration was forecasted to 
be above 65 [mu]g/m \3\ or the PM<INF>10</INF> concentration was 
forecasted to be above 135 [mu]g/m \3\. In 2019 the District adopted 
revisions to Rule 4901 to lower the wood burning curtailment thresholds 
in the ``hot spot'' counties of Madera, Fresno, and Kern. The District 
lowered the level one PM<INF>2.5</INF> threshold for these three 
counties from 20 [mu]g/m \3\ to 12 [mu]g/m \3\, and the level two 
PM<INF>2.5</INF> threshold from 65 [mu]g/m \3\ to 35 [mu]g/m \3\. The 
District did not modify the curtailment thresholds for other counties 
in the San Joaquin Valley--those levels remain at 20 [mu]g/m \3\ for 
level one and 65 [mu]g/m \3\ for level two.
    The District's 2019 revision to Rule 4901 also included the 
addition of a contingency measure in section 5.7.3 of the rule, 
requiring that 60 days following the effective date of an EPA 
determination that the San Joaquin Valley has failed to attain the 
1997, 2006, or 2012 PM<INF>2.5</INF> NAAQS by the applicable attainment 
date, the PM<INF>2.5</INF> curtailment levels of any county that has 
failed to attain the applicable standard will be lowered to the 
curtailment levels in place for hot spot counties. The District 
estimates that the potential emissions reduction of direct 
PM<INF>2.5</INF> would be in the range of 0.014 tpd (if the contingency 
measure is triggered in Kings County but not the other non-hot spot 
counties) to 0.387 tpd (if the contingency measure is triggered in all 
five of the non-hot spot counties), but there would be no emissions 
reduction if, at the time of the determination of failure to attain the 
1997 annual PM<INF>2.5</INF> NAAQS by the attainment date, violations 
of the 1997 annual PM<INF>2.5</INF> NAAQS are observed only at monitors 
in the hot spot counties.\167\ The corresponding potential 
NO<INF>X</INF> emissions reduction would be in the range of 0.002 tpd 
to 0.060 tpd, respectively, but once again, there would be no emissions 
reduction if the violations are monitored in the hot spot counties 
only.\168\ The EPA has already approved Rule 4901, as amended in 2019, 
as a revision to the California SIP.\169\
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    \167\ See Table B-13 in Appendix B from the District's Final 
Staff Report (June 20, 2019) for revisions to Rule 4901.
    \168\ NO<INF>X</INF> emissions reductions from the contingency 
measure are based on the District's estimates for direct 
PM<INF>2.5</INF> emissions using the ratio of direct 
PM<INF>2.5</INF> to NO<INF>X</INF> in Table 1, page 8, of the 
District's Final Staff Report (June 20, 2019) for revisions to Rule 
4901.
    \169\ 85 FR 44206 (July 22, 2020).
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    Appendix H of the 2018 PM<INF>2.5</INF> Plan also provides updated 
emissions estimates for the year following the State's projected 
attainment year (i.e., 2021) to evaluate whether the emission 
reductions from the contingency measures are sufficient. Table H-3 in 
Appendix H of the 2018 PM<INF>2.5</INF> Plan shows that the emission 
reductions between 2020 and 2021 are estimated to be 0.5 tpd of direct 
PM<INF>2.5</INF> and 12.3 tpd of NO<INF>X</INF> (based on the annual 
average inventory).
3. The EPA's Evaluation and Proposed Action
    We have evaluated the contingency provision in Rule 4901 (i.e., 
section 5.7.3 of the rule) for compliance with the requirements of CAA 
section 172(c)(9) and 40 CFR 51.1014 and find that the measure meets 
some, but not all, of the applicable requirements for contingency 
measures. The contingency provision in Rule 4901 is structured to be 
undertaken if the area fails to attain the 1997 PM<INF>2.5</INF> NAAQS, 
not before, and therefore is consistent with the Bahr decision 
disallowing already-implemented measures for contingency measure 
purposes under CAA section 172(c)(9). Furthermore, the contingency 
provision in Rule 4901 would achieve emission reductions above and 
beyond those that are projected to be achieved if the EPA finds that 
monitoring locations in counties outside of Fresno, Kern, or Madera 
counties (i.e., the ``hot spot'' counties listed in the rule) are 
violating the 1997 annual PM<INF>2.5</INF> NAAQS as of the attainment 
date. In accordance with 40 CFR 51.1014, the contingency provision in 
Rule 4901 identifies a specific triggering mechanism. In this case, the 
triggering mechanism in the rule is the EPA's final determination that 
San Joaquin Valley has failed to attain the 1997 annual 
PM<INF>2.5</INF> NAAQS by the applicable attainment date.\170\ The rule 
also specifies a timeframe within which its requirements become 
effective after a failure-to-attain determination (i.e., 60 days from 
the effective date of the EPA's final determination), and would take 
effect with minimal further action by the State or the EPA.
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    \170\ Section 5.7.3 of Rule 4901 states that ``the District 
shall notify the public of an Episodic Curtailment for the 
PM<INF>2.5</INF> curtailment levels described in Sections 5.7.1.2 
and 5.7.2.2 for any county that has failed to attain the applicable 
standard.'' (emphasis added) We interpret this to mean that the 
District would apply the more stringent curtailment provisions for 
any county identified in the EPA's final rule making the 
determination that the San Joaquin Valley failed to attain the 
applicable PM<INF>2.5</INF> NAAQS.
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    Conversely, we have identified several deficiencies with respect to 
the contingency measure element of the SJV PM<INF>2.5</INF> Plan. 
First, the contingency provisions of Rule 4901 do not address the 
potential for State failures to meet RFP, to meet a quantitative 
milestone, or to submit a quantitative milestone report. In addition, 
the contingency measure provisions of Rule 4901 are not structured to 
achieve any additional emissions reductions if the EPA finds that the 
monitoring locations in the ``hot spot'' counties (i.e., Fresno, Kern, 
or Madera) are the only counties in the San Joaquin Valley that are 
violating the 1997 annual PM<INF>2.5</INF> NAAQS as of the attainment 
date. To qualify as a contingency measure, a measure must be structured 
to achieve emissions reductions if triggered; however, the contingency 
provisions of Rule 4901 provide for such reductions only under certain 
circumstances. Thus, the contingency provisions of Rule 4901 should be 
revised to provide for additional emissions reductions in the San 
Joaquin Valley (if triggered) regardless of which monitoring site(s) is 
determined to be violating the 1997 annual PM<INF>2.5</INF> NAAQS as of 
the attainment date.
    Furthermore, CAA section 172(c)(9) requires that the plan provide 
for the implementation of contingency measures to be undertaken if the 
area fails to attain the 1997 annual PM<INF>2.5</INF> NAAQS by the 
applicable attainment date. Given our proposed disapproval of the 
State's attainment demonstration for the 1997 annual PM<INF>2.5</INF> 
NAAQS, as described in section IV.D.3 of this proposed rule, it is not 
possible to determine whether emission reductions from contingency 
measures in the SJV PM<INF>2.5</INF> Plan that are intended to take 
effect upon an EPA finding that the area failed to attain the standards 
are in fact surplus to the attainment demonstration, as required by 
section 172(c)(9).
    For these reasons, we are proposing to disapprove the contingency 
measure element of the SJV PM<INF>2.5</INF> Plan for the 1997 annual 
PM<INF>2.5</INF> NAAQS. If we finalize this proposal, we will remove 
from the California SIP the contingency provision in Rule 4901 (section 
5.7.3) because this provision does not satisfy CAA requirements for 
contingency measures and is severable from the remainder of Rule 4901. 
The disapproval of section 5.7.3 of Rule 4901 would have no effect on 
our prior approval of the rule for purposes of meeting the BACM and MSM 
requirements for the 2006 PM<INF>2.5</INF> NAAQS in the San Joaquin 
Valley,\171\ which

[[Page 38670]]

would remain in effect for all but section 5.7.3 of Rule 4901.
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    \171\ 85 FR 44206 (final approval of Rule 4901) and 85 FR 44192 
(determination that Rule 4901 implements BACM and MSM for 
residential wood burning).
---------------------------------------------------------------------------

G. Motor Vehicle Emission Budgets

1. Statutory and Regulatory Requirements
    Section 176(c) of the CAA requires federal actions in nonattainment 
and maintenance areas to conform to the goals of the state's SIP to 
eliminate or reduce the severity and number of violations of the NAAQS 
and achieve timely attainment of the standards. Conformity to the SIP's 
goals means that such actions will not: (1) Cause or contribute to 
violations of a NAAQS, (2) worsen the severity of an existing 
violation, or (3) delay timely attainment of any NAAQS or any interim 
milestone.
    Actions involving Federal Highway Administration (FHWA) or Federal 
Transit Administration (FTA) funding or approval are subject to the 
EPA's transportation conformity rule, codified at 40 CFR part 93, 
subpart A. Under this rule, metropolitan planning organizations (MPOs) 
in nonattainment and maintenance areas coordinate with state and local 
air quality and transportation agencies, the EPA, the FHWA, and the FTA 
to demonstrate that an area's regional transportation plans (RTPs) and 
transportation improvement programs conform to the applicable SIP. This 
demonstration is typically done by showing that estimated emissions 
from existing and planned highway and transit systems are less than or 
equal to the motor vehicle emissions budgets (MVEBs or ``budgets'') 
contained in all control strategy SIPs. Budgets are generally 
established for specific years and specific pollutants or precursors 
and must reflect all of the motor vehicle control measures contained in 
the attainment and RFP demonstrations.\172\
---------------------------------------------------------------------------

    \172\ 40 CFR 93.118(e)(4)(v).
---------------------------------------------------------------------------

    Under the PM<INF>2.5</INF> SIP Requirements Rule, Serious area 
PM<INF>2.5</INF> attainment plans must include appropriate quantitative 
milestones and projected RFP emission levels for direct 
PM<INF>2.5</INF> and all PM<INF>2.5</INF> plan precursors in each 
milestone year.\173\ For an area designated nonattainment for the 1997 
PM<INF>2.5</INF> NAAQS before January 15, 2015, the attainment plan 
must contain quantitative milestones to be achieved no later than three 
years after December 31, 2014, and every three years thereafter until 
the milestone date that falls within three years after the applicable 
attainment date.\174\ As the EPA explained in the preamble to the 
PM<INF>2.5</INF> SIP Requirements Rule, it is important to include a 
post-attainment year quantitative milestone to ensure that, if the area 
fails to attain by the attainment date, the EPA can continue to monitor 
the area's progress toward attainment while the state develops a new 
attainment plan.\175\ Although the post-attainment year quantitative 
milestone is a required element of a Serious area plan, it is not 
necessary to demonstrate transportation conformity for 2023 or to use 
the 2023 budgets in transportation conformity determinations until such 
time as the area fails to attain the 1997 annual PM<INF>2.5</INF> 
NAAQS.
---------------------------------------------------------------------------

    \173\ 40 CFR 51.1012(a), 51.1013(a)(1).
    \174\ 40 CFR 51.1013(a)(4) and 81 FR 58010, 58058 and 58063-
58064 (August 24, 2016).
    \175\ 81 FR 58010, 58063-58064.
---------------------------------------------------------------------------

    PM<INF>2.5</INF> plans should identify budgets for direct 
PM<INF>2.5</INF>, NO<INF>X</INF>, and all other PM<INF>2.5</INF> 
precursors for which on-road emissions are determined to significantly 
contribute to PM<INF>2.5</INF> levels in the area for each RFP 
milestone year and the attainment year, if the plan demonstrates 
attainment. All direct PM<INF>2.5</INF> SIP budgets should include 
direct PM<INF>2.5</INF> motor vehicle emissions from tailpipes, brake 
wear, and tire wear. With respect to PM<INF>2.5</INF> from re-entrained 
road dust and emissions of VOC, SO<INF>2</INF>, and/or ammonia, the 
transportation conformity provisions of 40 CFR part 93, subpart A, 
apply only if the EPA Regional Administrator or the director of the 
state air agency has made a finding that emissions of these pollutants 
within the area are a significant contributor to the PM<INF>2.5</INF> 
nonattainment problem and has so notified the MPO and Department of 
Transportation (DOT), or if the applicable implementation plan (or 
implementation plan submission) includes any of these pollutants in the 
approved (or adequate) budget as part of the RFP, attainment, or 
maintenance strategy.\176\
---------------------------------------------------------------------------

    \176\ 40 CFR 93.102(b)(3), 93.102(b)(2)(v), and 93.122(f); see 
also Conformity Rule preambles at 69 FR 40004, 40031-40036 (July 1, 
2004), 70 FR 24280, 24283-24285 (May 6, 2005) and 70 FR 31354 (June 
1, 2005).
---------------------------------------------------------------------------

    By contrast, transportation conformity requirements apply with 
respect to emissions of NO<INF>X</INF> unless both the EPA Regional 
Administrator and the director of the state air agency have made a 
finding that transportation-related emissions of NO<INF>X</INF> within 
the nonattainment area are not a significant contributor to the 
PM<INF>2.5</INF> nonattainment problem and have so notified the MPO and 
DOT, or the applicable implementation plan (or implementation plan 
submission) does not establish an approved (or adequate) budget for 
such emissions as part of the RFP, attainment, or maintenance 
strategy.\177\
---------------------------------------------------------------------------

    \177\ 40 CFR 93.102(b)(2)(iv).
---------------------------------------------------------------------------

    It is not always necessary for states to establish motor vehicle 
emissions budgets for all PM<INF>2.5</INF> precursors. The 
PM<INF>2.5</INF> SIP Requirements Rule allows a state to demonstrate 
that emissions of certain precursors do not contribute significantly to 
PM<INF>2.5</INF> levels that exceed the NAAQS in a nonattainment area, 
in which case the state may exclude such precursor(s) from its control 
evaluations for the specific NAAQS at issue. If a state successfully 
demonstrates that the emissions of one or more of the PM<INF>2.5</INF> 
precursors from all sources do not contribute significantly to 
PM<INF>2.5</INF> levels in the subject area, then it is not necessary 
to establish motor vehicle emissions budgets for such precursor(s).
    Alternatively, the transportation conformity regulations contain 
criteria for determining whether emissions of one or more 
PM<INF>2.5</INF> precursors are insignificant for transportation 
conformity purposes.\178\ For a pollutant or precursor to be considered 
an insignificant contributor based on the transportation conformity 
rule's criteria, the control strategy SIP must demonstrate that it 
would be unreasonable to expect that such an area would experience 
enough motor vehicle emissions growth in that pollutant and/or 
precursor for a NAAQS violation to occur. Insignificance determinations 
are based on factors such as air quality, SIP motor vehicle control 
measures, trends and projections of motor vehicle emissions, and the 
percentage of the total attainment plan emissions inventory for the 
NAAQS at issue that is comprised of motor vehicle emissions. The EPA's 
rationale for providing for insignificance determinations is described 
in the July 1, 2004 revision to the Transportation Conformity 
Rule.\179\
---------------------------------------------------------------------------

    \178\ 40 CFR 93.109(f).
    \179\ 69 FR 40004.
---------------------------------------------------------------------------

    Transportation conformity trading mechanisms are allowed under 40 
CFR 93.124 where a state establishes appropriate mechanisms for such 
trades. The basis for the trading mechanism is the SIP attainment 
modeling that establishes the relative contribution of each 
PM<INF>2.5</INF> precursor pollutant. The applicability of emission 
trading between conformity budgets for conformity purposes is described 
in 40 CFR 93.124(c).
    The EPA's process for determining the adequacy of a budget consists 
of three

[[Page 38671]]

basic steps: (1) Notifying the public of a SIP submittal; (2) providing 
the public the opportunity to comment on the budget during a public 
comment period; and, (3) making a finding of adequacy or inadequacy. 
The EPA can notify the public by either posting an announcement that 
the EPA has received SIP budgets on the EPA's adequacy website,\180\ or 
through a Federal Register notice of proposed rulemaking when the EPA 
reviews the adequacy of an implementation plan budget simultaneously 
with its review and action on the SIP itself.\181\
---------------------------------------------------------------------------

    \180\ 40 CFR 93.118(f)(1).
    \181\ 40 CFR 93.118(f)(2).
---------------------------------------------------------------------------

2. Summary of the State's Submission
    The 2018 PM<INF>2.5</INF> Plan includes budgets for direct 
PM<INF>2.5</INF> and NO<INF>X</INF> emissions, calculated using annual 
average daily emissions, for 2017, 2020, and 2023 (RFP milestone year, 
attainment year, and post-attainment quantitative milestone year, 
respectively).\182\ The Plan establishes separate direct 
PM<INF>2.5</INF> and NO<INF>X</INF> subarea budgets for each county, or 
partial county (for Kern County), in the San Joaquin Valley.\183\ CARB 
calculated the budgets using EMFAC2014, CARB's latest version of the 
EMFAC model for estimating emissions from on-road vehicles operating in 
California that was available at the time of Plan development, and the 
latest modeled vehicle miles traveled and speed distributions from the 
San Joaquin Valley MPOs from the Final 2017 Federal Transportation 
Improvement Program, adopted in September 2016. The budgets reflect 
annual average emissions because those emissions are linked with the 
District's attainment demonstration for the 1997 annual 
PM<INF>2.5</INF> NAAQS.
---------------------------------------------------------------------------

    \182\ 2018 PM<INF>2.5</INF> Plan, Appendix D, Table 3-1.
    \183\ 40 CFR 93.124(c) and (d).
---------------------------------------------------------------------------

    The direct PM<INF>2.5</INF> budgets include tailpipe, brake wear, 
and tire wear emissions but do not include paved road dust, unpaved 
road dust, and road construction dust emissions.\184\ The State is not 
required to include re-entrained road dust in the budgets under section 
93.103(b)(3) unless the EPA or the State has made a finding that these 
emissions are significant. Neither the State nor the EPA has made such 
a finding, but the Plan does include a discussion of the significance/
insignificance factors for re-entrained road dust.\185\ The budgets 
included in the 2018 PM<INF>2.5</INF> Plan for purposes of the 1997 
annual PM<INF>2.5</INF> NAAQS are shown in Table 6.
---------------------------------------------------------------------------

    \184\ 2018 PM<INF>2.5</INF> Plan, Appendix D, D-122 to D-123.
    \185\ 2018 PM<INF>2.5</INF> Plan, Appendix D, D-121 and D-122.

       Table 6--Motor Vehicle Emission Budgets for the San Joaquin Valley for the 1997 Annual PM2.5 NAAQS
                                              [Annual average, tpd]
----------------------------------------------------------------------------------------------------------------
                                         2017 (RFP year)       2020 (Attainment year)     2023 (Post-attainment
                                   ----------------------------------------------------           year)
              County                                                                   -------------------------
                                       PM2.5         NOX         PM2.5         NOX         PM2.5         NOX
----------------------------------------------------------------------------------------------------------------
Fresno............................          0.9         28.5          0.9         25.3          0.8         15.1
Kern..............................          0.8         28.0          0.8         23.3          0.7         13.3
Kings.............................          0.2          5.8          0.2          4.8          0.2          2.8
Madera............................          0.2          5.3          0.2          4.2          0.2          2.5
Merced............................          0.3         10.7          0.3          8.9          0.3          5.3
San Joaquin.......................          0.7         14.9          0.6         11.9          0.6          7.6
Stanislaus........................          0.4         11.9          0.4          9.6          0.4          6.1
Tulare............................          0.4         10.8          0.4          8.5          0.4          5.2
----------------------------------------------------------------------------------------------------------------
Source: 2018 PM2.5 Plan, Appendix D, Table 3-1. Budgets are rounded to the nearest tenth of a ton.

    The State did not include budgets for VOC, SO<INF>2</INF>, or 
ammonia. As discussed in section IV.B of this proposed rule, the State 
submitted a PM<INF>2.5</INF> precursor demonstration documenting its 
conclusion that control of these precursors would not significantly 
contribute to attainment of the 1997 annual PM<INF>2.5</INF> NAAQS. The 
State also included a discussion of the significance/insignificance 
factors for ammonia, SO<INF>2</INF>, and VOC to demonstrate a finding 
of insignificance under the transportation conformity rule.\186\
---------------------------------------------------------------------------

    \186\ 40 CFR 93.109(f).
---------------------------------------------------------------------------

    In the submittal letter for the 2018 PM<INF>2.5</INF> Plan, CARB 
requested that the EPA limit the duration of the approval of the 
budgets to the period before the effective date of the EPA's adequacy 
finding for any subsequently submitted budgets.\187\
---------------------------------------------------------------------------

    \187\ Letter dated May 9, 2019, from Richard W. Corey, Executive 
Officer, CARB, to Mike Stoker, Regional Administrator, EPA Region 9, 
3.
---------------------------------------------------------------------------

Conformity Trading Mechanism
    The 2018 PM<INF>2.5</INF> Plan also includes a proposed trading 
mechanism for transportation conformity analyses that would allow 
future decreases in NO<INF>X</INF> emissions from on-road mobile 
sources to offset any on-road increases in direct PM<INF>2.5</INF> 
emissions. The State is proposing to use a 6.5 to 1 NO<INF>X</INF> to 
PM<INF>2.5</INF> ratio for the 1997 annual PM<INF>2.5</INF> NAAQS. This 
ratio was derived by performing a sensitivity analysis based on a 30 
percent reduction of NO<INF>X</INF> or PM<INF>2.5</INF> emissions and 
calculating the corresponding effect on design values at sites in 
Bakersfield and Fresno.
    To ensure that the trading mechanism does not affect the ability of 
the San Joaquin Valley to meet the NO<INF>X</INF> budget, the 
NO<INF>X</INF> emissions reductions available to supplement the 
PM<INF>2.5</INF> budget would be only those remaining after the 
NO<INF>X</INF> budget has been met.\188\ The Plan also provides that 
the San Joaquin Valley MPOs shall clearly document the calculations 
used in the trading, along with any additional reductions of 
NO<INF>X</INF> and PM<INF>2.5</INF> emissions in the conformity 
analysis.
---------------------------------------------------------------------------

    \188\ 2018 PM<INF>2.5</INF> Plan, Appendix D, D-126 and D-127.
---------------------------------------------------------------------------

3. The EPA's Evaluation and Proposed Action
    The EPA generally first conducts a preliminary review of budgets 
submitted with an attainment or maintenance plan for PM<INF>2.5</INF> 
for adequacy, prior to taking action on the plan itself, and did so 
with respect to the PM<INF>2.5</INF> budgets in the 2018 
PM<INF>2.5</INF> Plan. On June 18, 2019, the EPA announced the 
availability of the 2018 PM<INF>2.5</INF> Plan with MVEBs and a 30-day 
public comment period. This announcement was posted on the EPA's 
Adequacy website at: https://www.epa.gov/state-and-local-

[[Page 38672]]

transportation/state-implementation-plans-sip-submissions-currently-
under-epa. The comment period for this notification ended on July 18, 
2019. We did not receive any comments during this comment period.
    We have reviewed the motor vehicle emissions budgets in the 2018 
PM<INF>2.5</INF> Plan and find that, because we are proposing to 
disapprove the attainment demonstration and related elements of the SJV 
PM<INF>2.5</INF> Plan for purposes of the 1997 annual PM<INF>2.5</INF> 
NAAQS based on the area's failure to attain by the State's projected 
attainment date, the budgets cannot be consistent with the applicable 
requirements for RFP and attainment of the 1997 annual PM<INF>2.5</INF> 
NAAQS. Therefore, we are proposing to find that the motor vehicle 
emissions budgets do not meet applicable statutory and regulatory 
requirements, including the adequacy criteria specified in the 
transportation conformity rule.\189\ As discussed earlier in sections 
IV.C, IV.D, and IV.E, we are proposing to disapprove the Plan's five 
percent, attainment, and RFP demonstrations. In addition, because we 
are proposing to disapprove the five percent and RFP demonstrations, 
the budgets are not consistent with the applicable requirements for the 
five percent annual reductions and RFP. Therefore, we are proposing to 
disapprove the budgets in the SJV PM<INF>2.5</INF> Plan. Our proposed 
disapproval relates only to the 1997 annual PM<INF>2.5</INF> NAAQS, and 
does not affect the status of the budgets for the 1997 24-hour 
PM<INF>2.5</INF> NAAQS or the previously-approved budgets for the 2006 
PM<INF>2.5</INF> NAAQS and related trading mechanism, which remain in 
effect for those PM<INF>2.5</INF> NAAQS. Because we are disapproving 
the attainment and RFP demonstrations, the budgets are not eligible for 
a protective finding.\190\
---------------------------------------------------------------------------

    \189\ 40 CFR 93.118(e)(4).
    \190\ 40 CFR 93.120(a)(3).
---------------------------------------------------------------------------

    If our proposed disapproval of the budgets is finalized, upon the 
effective date of our final rule, the area would be subject to a 
conformity freeze under 40 CFR 93.120 of the transportation conformity 
rule. No new transportation plan, transportation improvement program 
(TIP), or project may be found to conform until the State submits 
another control strategy implementation plan revision fulfilling the 
same CAA requirements, the EPA finds the budgets in the revised plan 
adequate or approves the budgets, the MPO makes a conformity 
determination for the new budgets, and the U.S. Department of 
Transportation makes a conformity determination.\191\ In addition, only 
transportation projects outside of the first four years of the current 
conforming transportation plan and TIP or that meets the requirements 
of 40 CFR 93.104(f) during the resulting conformity freeze may be found 
to conform until California submits a new attainment plan for the 1997 
annual PM<INF>2.5</INF> NAAQS and (1) the EPA finds the submitted 
budgets adequate per 40 CFR 93.118 or (2) the EPA approves the new 
attainment plan and conformity to the new plan is determined.\192\ 
Furthermore, if, as a result of our final disapproval action, the EPA 
imposes highway sanctions under section 179(b)(1) of the Act two years 
from the effective date of our final rule, then the conformity status 
of the transportation plan and TIP will lapse on that date and no new 
transportation plan, TIP, or project may be found to conform until 
California submits a new plan for the 1997 annual PM<INF>2.5</INF> 
NAAQS, and conformity to the plan is determined.\193\
---------------------------------------------------------------------------

    \191\ 40 CFR 93.120(a)(2).
    \192\ Id.
    \193\ 40 CFR 93.120(a)(1).
---------------------------------------------------------------------------

H. Nonattainment New Source Review Requirements Under CAA Section 
189(e)

    CAA section 189(e) specifically requires that the control 
requirements applicable to major stationary sources of direct 
PM<INF>2.5</INF> also apply to major stationary sources of 
PM<INF>2.5</INF> precursors, except where the Administrator determines 
that such sources do not contribute significantly to PM<INF>2.5</INF> 
levels that exceed the standards in the area.\194\ The control 
requirements applicable to major stationary sources of direct 
PM<INF>2.5</INF> in a Serious PM<INF>2.5</INF> nonattainment area 
include, at minimum, the requirements of a nonattainment NSR permit 
program meeting the requirements of CAA sections 172(c)(5) and 
189(b)(3). As part of our April 7, 2015 final action to reclassify the 
San Joaquin Valley area as Serious nonattainment for the 1997 
PM<INF>2.5</INF> standards, we established a May 7, 2016 deadline for 
the State to submit nonattainment NSR SIP revisions addressing the 
requirements of CAA sections 189(b)(3) and 189(e) of the Act for the 
1997 PM<INF>2.5</INF> NAAQS.
---------------------------------------------------------------------------

    \194\ General Preamble, 13539 and 13541-13542.
---------------------------------------------------------------------------

    California submitted nonattainment NSR SIP revisions to address the 
subpart 4 requirements for the San Joaquin Valley Serious 
PM<INF>2.5</INF> nonattainment area on November 20, 2019. We are not 
proposing any action on this submission at this time. We will act on 
this submission through a separate rulemaking, as appropriate.

V. Proposed Action

    For the reasons discussed in this proposed rule, under CAA section 
110(k)(3), the EPA is proposing to approve in part and disapprove in 
part the portions of the SJV PM<INF>2.5</INF> Plan that pertain to the 
1997 annual PM<INF>2.5</INF> NAAQS for the San Joaquin Valley 
nonattainment area as follows:
    (1) We are proposing to approve the 2013 base year emissions 
inventories as meeting the requirements of CAA section 172(c)(3) and 40 
CFR 51.1008; and
    (2) We are proposing to disapprove the following elements:
    (a) The precursor demonstration as not meeting the requirements of 
40 CFR 51.1006,
    (b) The BACM/BACT demonstration as not meeting the requirements of 
CAA section 189(b)(1)(B) and 40 CFR 51.1010,
    (c) The five percent demonstration as not meeting the requirements 
of CAA section 189(d) and 40 CFR 51.1010(c),
    (d) The attainment demonstration as not meeting the requirements of 
CAA sections 189(d) and 179(d) and 40 CFR 51.1011(b),
    (e) The RFP demonstration as not meeting the requirements of CAA 
sections 172(c)(2) and 171(1) and 40 CFR 51.1012,
    (f) The quantitative milestone demonstration as not meeting the 
requirements of CAA section 189(c) and 40 CFR 51.1013,
    (g) The contingency measures as not meeting the requirements of CAA 
section 172(c)(9) and 40 CFR 51.1014, and
    (h) The motor vehicle emissions budgets as not meeting the 
requirements of CAA section 176(c) and 40 CFR 93.118(e)(4).

A. Effect of Finalizing the Proposed Disapproval Actions

    If we finalize disapprovals of the precursor demonstration, BACM/
BACT demonstration, five percent demonstration, attainment 
demonstration, RFP and milestone demonstrations, motor vehicle emission 
budgets, or contingency measures, the offset sanction in CAA section 
179(b)(2) will be applied in the San Joaquin Valley area 18 months 
after the effective date of such final disapproval. For new or modified 
major stationary sources in the area, the ratio of emission reductions 
to increased emissions shall be at least 2 to 1. The highway funding 
sanctions in CAA section 179(b)(1) will apply in the area six months 
after the offset sanction is imposed. Neither sanction will be imposed 
if California

[[Page 38673]]

submits and we approve SIP revisions meeting the applicable CAA 
requirements prior to the implementation of the sanctions.\195\
---------------------------------------------------------------------------

    \195\ See 40 CFR 52.31, which sets forth in detail the sanctions 
consequences of a final disapproval.
---------------------------------------------------------------------------

    In addition to the sanctions, CAA section 110(c)(1) provides that 
the EPA must promulgate a federal implementation plan (FIP) addressing 
any disapproved elements of the plan two years after the effective date 
of disapproval unless the State submits, and the EPA approves, the 
required SIP submittal. As a result of the EPA's December 6, 2018 
determination that California had failed to submit the required 
attainment plan for the 1997 PM<INF>2.5</INF> NAAQS, among other 
required SIP submissions for the San Joaquin Valley,\196\ the EPA is 
already subject to a statutory deadline to promulgate a FIP for this 
purpose no later than two years after the effective date of that 
determination.\197\
---------------------------------------------------------------------------

    \196\ 83 FR 62720.
    \197\ Id.
---------------------------------------------------------------------------

    Furthermore, if we take final action disapproving the SJV 
PM<INF>2.5</INF> Plan, a conformity freeze will take effect upon the 
effective date of any final disapproval (usually 30 days after 
publication of the final action in the Federal Register). A conformity 
freeze means that only projects in the first four years of the most 
recent RTP and TIP can proceed. During a freeze, no new RTPs, TIPs, or 
RTP/TIP amendments can be found to conform.\198\
---------------------------------------------------------------------------

    \198\ See 40 CFR 93.120(a).
---------------------------------------------------------------------------

    Finally, if the EPA takes final action on the SJV PM<INF>2.5</INF> 
Plan as proposed, California will be required to develop and submit a 
revised plan for the San Joaquin Valley area that addresses the 
applicable CAA requirements, including the requirements of CAA section 
189(d). In accordance with sections 179(d)(3) and 172(a)(2) of the CAA, 
the revised plan must demonstrate attainment as expeditiously as 
practicable and no later than five years from the date of the EPA's 
determination that the area failed to attain (i.e., by November 23, 
2021), except that the EPA may extend the attainment date to a date no 
later than 10 years from the date of this determination (i.e., to 
November 23, 2026), considering the severity of nonattainment and the 
availability and feasibility of pollution control measures.\199\
---------------------------------------------------------------------------

    \199\ 81 FR 84481, 84482 (November 23, 2016) (final EPA action 
determining that the San Joaquin Valley had failed to attain the 
1997 PM<INF>2.5</INF> NAAQS by the December 31, 2015 Serious area 
attainment date).
---------------------------------------------------------------------------

    The EPA is soliciting public comments on the issues discussed in 
this proposed rule. We will accept comments from the public on this 
proposal for the next 30 days.

VI. Incorporation by Reference

    In this document, the EPA is proposing to amend regulatory text 
that includes incorporation by reference. As explained in section 
IV.F.3 of this preamble, the EPA is proposing to remove section 5.7.3 
of SJVUAPCD Rule 4901 from the California State Implementation Plan, 
which is incorporated by reference in accordance with the requirements 
of 1 CFR part 51.

VII. Statutory and Executive Order Reviews

    Additional information about these statutes and Executive Orders 
can be found at http://www2.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.

B. Paperwork Reduction Act (PRA)

    This action does not impose an information collection burden under 
the PRA because this proposed SIP disapproval, if finalized, will not 
in-and-of itself create any new information collection burdens but will 
simply disapprove certain State requirements for inclusion in the SIP.

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. This 
proposed SIP disapproval, if finalized, will not in-and-of itself 
create any new requirements but will simply disapprove certain state 
requirements for inclusion in the SIP.

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 proposes to disapprove pre-existing 
requirements under state or local law and imposes no new requirements. 
Accordingly, no additional costs to state, local, or tribal 
governments, or to the private sector, 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.

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 revision that the EPA is 
proposing to disapprove would not 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.

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 2-202 of the Executive Order. This action is not subject to 
Executive Order 13045 because this proposed SIP disapproval, if 
finalized, will not in-and-of itself create any new regulations but 
will simply disapprove certain state requirements for inclusion in the 
SIP.

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.

[[Page 38674]]

J. Executive Order 12898: Federal Actions To Address Environmental 
Justice in Minority Populations and Low-Income Population

    The EPA lacks the discretionary authority to address environmental 
justice in this rulemaking.

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: July 12, 2021.
Deborah Jordan,
Acting Regional Administrator, Region IX.
[FR Doc. 2021-15551 Filed 7-21-21; 8:45 am]
BILLING CODE 6560-50-P


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