Proposed Rule2021-20613
Partial Approval and Partial Disapproval of Air Quality Implementation Plans and Determination of Attainment by the Attainment Date; California; San Joaquin Valley Serious Area and Section 189(d) Plan for Attainment of the 1997 24-Hour PM2.5 NAAQS
Primary source
Metadata and text below are from the Federal Register, a public-domain U.S. government work. Always verify the official published version before relying on it for any legal matter.
Published
September 24, 2021
Issuing agencies
Environmental Protection Agency
Abstract
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 24- hour fine particulate matter (PM<INF>2.5</INF>) national ambient air quality standards (NAAQS) in the San Joaquin Valley nonattainment area. Specifically, the EPA is proposing to approve all but the contingency measure element of the submitted SIP revision as meeting all applicable Serious area and CAA section 189(d) requirements for the 1997 24-hour PM<INF>2.5</INF> NAAQS and is proposing disapproval of the contingency measure element. The EPA is also proposing to determine that the San Joaquin Valley air quality planning area has attained the 1997 24-hour PM<INF>2.5</INF> NAAQS. This determination is based on sufficient, quality-assured, and certified data for 2018-2020. Based on our proposed finding that the San Joaquin Valley nonattainment area has attained the 1997 24-hour PM<INF>2.5</INF> NAAQS, we are proposing to determine that the requirement for contingency measures will no longer apply to the San Joaquin Valley nonattainment area for these NAAQS. Thus, the EPA is proposing to issue a protective finding for transportation conformity determinations for this proposed disapproval.
Full Text
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<title>Federal Register, Volume 86 Issue 183 (Friday, September 24, 2021)</title>
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[Federal Register Volume 86, Number 183 (Friday, September 24, 2021)]
[Proposed Rules]
[Pages 53150-53184]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2021-20613]
[[Page 53149]]
Vol. 86
Friday,
No. 183
September 24, 2021
Part II
Environmental Protection Agency
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40 CFR Part 52
Partial Approval and Partial Disapproval of Air Quality Implementation
Plans and Determination of Attainment by the Attainment Date;
California; San Joaquin Valley Serious Area and Section 189(d) Plan for
Attainment of the 1997 24-Hour PM2.5 NAAQS; Proposed Rule
Federal Register / Vol. 86 , No. 183 / Friday, September 24, 2021 /
Proposed Rules
[[Page 53150]]
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ENVIRONMENTAL PROTECTION AGENCY
40 CFR Part 52
[EPA-R09-OAR-2021-0261; FRL-8969-01-R9]
Partial Approval and Partial Disapproval of Air Quality
Implementation Plans and Determination of Attainment by the Attainment
Date; California; San Joaquin Valley Serious Area and Section 189(d)
Plan for Attainment of the 1997 24-Hour 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 24-
hour fine particulate matter (PM<INF>2.5</INF>) national ambient air
quality standards (NAAQS) in the San Joaquin Valley nonattainment area.
Specifically, the EPA is proposing to approve all but the contingency
measure element of the submitted SIP revision as meeting all applicable
Serious area and CAA section 189(d) requirements for the 1997 24-hour
PM<INF>2.5</INF> NAAQS and is proposing disapproval of the contingency
measure element. The EPA is also proposing to determine that the San
Joaquin Valley air quality planning area has attained the 1997 24-hour
PM<INF>2.5</INF> NAAQS. This determination is based on sufficient,
quality-assured, and certified data for 2018-2020. Based on our
proposed finding that the San Joaquin Valley nonattainment area has
attained the 1997 24-hour PM<INF>2.5</INF> NAAQS, we are proposing to
determine that the requirement for contingency measures will no longer
apply to the San Joaquin Valley nonattainment area for these NAAQS.
Thus, the EPA is proposing to issue a protective finding for
transportation conformity determinations for this proposed disapproval.
DATES: Any comments on this proposal must be received by October 25,
2021.
ADDRESSES: Submit your comments, identified by Docket ID No. EPA-R09-
OAR-2021-0261 at <a href="https://www.regulations.gov">https://www.regulations.gov</a>. For comments submitted at
<a href="http://Regulations.gov">Regulations.gov</a>, follow the online instructions for submitting
comments. Once submitted, comments cannot be edited or removed from
<a href="http://Regulations.gov">Regulations.gov</a>. The EPA may publish any comment received to its public
docket. Do not submit electronically any information you consider to be
Confidential Business Information (CBI) or other information whose
disclosure is restricted by statute. Multimedia submissions (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 <a href="https://www.epa.gov/dockets/commenting-epa-dockets">https://www.epa.gov/dockets/commenting-epa-dockets</a>. If you need assistance in a
language other than English or if you are a person with 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#c1a6b3a0a9a0acefa0b2a9ada4b8b381a4b1a0efa6aeb7"><span class="__cf_email__" data-cfemail="d3b4a1b2bbb2befdb2a0bbbfb6aaa193b6a3b2fdb4bca5">[email protected]</span></a>.
SUPPLEMENTARY INFORMATION: Throughout this document, ``we,'' ``us,'' or
``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
PM<INF>2.5</INF> Plan
A. 2018 PM<INF>2.5</INF> Plan
B. Valley State SIP Strategy
III. Clean Air Act Requirements for PM<INF>2.5</INF> Serious Area
Plans and for Serious PM<INF>2.5</INF> Areas That Fail To Attain
A. Requirements for PM<INF>2.5</INF> Serious Area Plans
B. Requirements for Serious PM<INF>2.5</INF> Areas That Fail To
Attain
IV. Review of the San Joaquin Valley PM<INF>2.5</INF> Plan for the
1997 24-Hour PM<INF>2.5</INF> NAAQS
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. Determination of Attainment by the Attainment Date
A. Requirements for Attainment Determinations
B. Monitoring Network Considerations
C. Data Considerations and Proposed Determination
VI. Summary of Proposed Action and Request for Public Comment
VII. 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 24-hour and annual
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 lowered the 24-hour and
annual PM<INF>2.5</INF> NAAQS, the 1997 24-hour PM<INF>2.5</INF> NAAQS
remain in effect and the 1997 primary annual PM<INF>2.5</INF> NAAQS
remains in effect in areas designated nonattainment for that NAAQS.\6\
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\4\ 71 FR 61144.
\5\ 78 FR 3086.
\6\ 40 CFR 50.13(d).
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The EPA established the 1997 PM<INF>2.5</INF> NAAQS after
considering substantial
[[Page 53151]]
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 older adults, people with heart
and lung disease, and children.\7\
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\7\ 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, and ammonia.\8\
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\8\ 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 24-hour and annual PM<INF>2.5</INF> NAAQS, using air quality
monitoring data for the three-year periods of 2001-2003 and 2002-
2004.\9\ The EPA designated the San Joaquin Valley as nonattainment for
both the 1997 24-hour PM<INF>2.5</INF> NAAQS (65 [mu]g/m\3\) and the
1997 annual PM<INF>2.5</INF> NAAQS (15.0 [mu]g/m\3\).\10\
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\9\ 70 FR 944 (January 5, 2005).
\10\ 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.\11\ 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 generally has
responsibility for regulating stationary and area sources, and CARB,
which generally has responsibility for regulating mobile sources.
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\11\ For a precise description of the geographic boundaries of
the San Joaquin Valley nonattainment area, see 40 CFR 81.305.
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At the time of the initial designations for the 1997
PM<INF>2.5</INF> NAAQS, the EPA interpreted the CAA to require
implementation of the NAAQS under the general nonattainment plan
requirements of subpart 1.\12\ Under subpart 1, states were required to
submit nonattainment plan SIP submissions within three years of the
effective date of designations, that, among other things, provided for
implementation of reasonably available control measures (RACM),
reasonable further progress (RFP), contingency measures, and a modeled
attainment demonstration showing attainment of the NAAQS as
expeditiously as practicable but no later than five years from the
designation (in this instance, no later than April 5, 2010) unless the
state justified an attainment date extension of up to five years.\13\
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\12\ 72 FR 20586.
\13\ 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 24-hour
and annual PM<INF>2.5</INF> NAAQS in the San Joaquin Valley,\14\ 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 24-hour and annual 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.\15\ 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.\16\
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\14\ 76 FR 69896, n. 2 (November 9, 2011).
\15\ Id. at 69924.
\16\ 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,\17\ the EPA
published a final rule on June 2, 2014, classifying the San Joaquin
Valley as a Moderate nonattainment area for the 1997 24-hour and annual
PM<INF>2.5</INF> NAAQS under subpart 4, part D of title I of the
Act.\18\ In this action, the EPA acknowledged that states must meet
both subpart 1 and subpart 4 requirements in nonattainment plan SIP
submissions for the 1997 24-hour and annual PM<INF>2.5</INF> NAAQS and
provided states with additional time to supplement or withdraw and
resubmit any pending nonattainment plan SIP submissions.
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\17\ 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 [micro]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.''
\18\ 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 the determination that the State could not practicably attain
these NAAQS in the San Joaquin Valley nonattainment area by the latest
statutory Moderate area attainment date, i.e., April 5, 2015.\19\ Upon
reclassification as a Serious area, the State became subject to the
requirement of CAA section 188(c)(2) to attain the 1997
PM<INF>2.5</INF> NAAQS, as expeditiously as practicable but no later
than ten years after designation, i.e., by no later than December 31,
2015. California submitted its 1997 PM<INF>2.5</INF> Serious area plan
for the San Joaquin Valley in two submissions dated June 25, 2015 and
August 13, 2015, including a request under section 188(e) to extend the
attainment date for the 1997 24-hour PM<INF>2.5</INF> NAAQS by three
years (to December 31, 2018) and to extend the attainment date for the
1997 annual PM<INF>2.5</INF> NAAQS by five years (to December 31,
2020). On February 9, 2016, the EPA proposed to approve most of the
Serious area plan and to
[[Page 53152]]
grant the State's request for extensions of the December 31, 2015
attainment date.\20\ However, on October 6, 2016, after considering
public comments, the EPA denied California's request for these
extensions of the attainment dates.\21\ Consequently, on November 23,
2016, the EPA determined that the San Joaquin Valley had failed to
attain the 1997 24-hour and annual PM<INF>2.5</INF> NAAQS by the
December 31, 2015 Serious area attainment date.\22\ This determination
triggered a requirement for California to submit a new SIP submission
for the 1997 24-hour and annual PM<INF>2.5</INF> NAAQS for the San
Joaquin Valley that satisfies the requirements of CAA section 189(d).
The statutory deadline for this additional SIP submission was December
31, 2016. The EPA did not finalize the actions proposed on February 9,
2016, with respect to the submitted Serious area plan.\23\
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\19\ 80 FR 18528 (April 7, 2015).
\20\ 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.
\21\ 81 FR 69396.
\22\ 81 FR 84481.
\23\ 81 FR 69396, 69400.
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On December 6, 2018, the EPA determined that California had failed
to submit a complete section 189(d) attainment plan for the 1997 24-
hour and annual PM<INF>2.5</INF> NAAQS, among other required SIP
submissions for the San Joaquin Valley, by the statutory deadlines.\24\
This finding, which became effective on January 7, 2019, triggered
clocks under CAA section 179(a) for the application of emissions offset
sanctions 18 months after the finding, and highway funding sanctions 6
months thereafter, unless the EPA affirmatively determined that the
State has made a complete SIP submission addressing the identified
failure to submit deficiencies.\25\ The finding also triggered the
obligation under CAA section 110(c) for the EPA to promulgate a federal
implementation plan no later than two years after the finding, unless
the State has submitted, and the EPA has approved, the required SIP
submission.\26\
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\24\ 83 FR 62720.
\25\ Id. at 62723.
\26\ Id.
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On May 10, 2019, CARB made SIP submissions intended to address the
Serious area nonattainment plan and CAA section 189(d) requirements for
the 1997 24-hour and annual PM<INF>2.5</INF> NAAQS, among other
requirements for the 2006 and 2012 PM<INF>2.5</INF> NAAQS.\27\ CARB
clarified in its May 10, 2019 letter that these new SIP submissions
superseded past submissions to the EPA that the agency had not yet
acted on for the 1997 PM<INF>2.5</INF> NAAQS, including the 2015
Serious area attainment plan submissions. On June 24, 2020, the EPA
issued a letter finding these submissions complete and terminating the
sanctions clocks under CAA section 179(a).\28\ The portions of these
SIP submissions that pertain to the 1997 24-hour PM<INF>2.5</INF> NAAQS
are the subject of this proposal.
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\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 PM<INF>2.5</INF> 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).
\28\ Letter dated June 24, 2020, from Elizabeth J. Adams,
Director, Air and Radiation Division, EPA Region IX, to Richard
Corey, Executive Officer, CARB, Subject: ``RE: Completeness Finding
for State Implementation Plan (SIP) Submissions for San Joaquin
Valley for the 1997, 2006, and 2012 Fine Particulate Matter
(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
PM[bdi2]<INF>.</INF>[bdi5] Plan
The EPA is proposing action on portions of two SIP submissions made
by CARB to address nonattainment plan requirements for the 1997 24-hour
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 SIP
submissions that pertain to the 1997 24-hour PM<INF>2.5</INF> NAAQS:
(i) 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''); \29\ and (ii) 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.\30\ We refer to these
two SIP submissions collectively as the ``SJV PM<INF>2.5</INF> Plan''
or ``Plan.''
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\29\ The 2018 PM<INF>2.5</INF> Plan was developed jointly by
CARB and the District.
\30\ Letter dated May 9, 2019, from Richard Corey, Executive
Officer, CARB, to Mike Stoker, Regional Administrator, EPA Region 9.
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 proposed action on those
portions pertaining to the 1997 annual PM<INF>2.5</INF> NAAQS (86 FR
38652, July 22, 2021) and 2012 annual PM<INF>2.5</INF> NAAQS (86 FR
49100, September 1, 2021). The EPA is not, at this time, taking any
action on those portions that pertain to the 1997 annual
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 SJV PM<INF>2.5</INF> Plan addresses the Serious area
nonattainment plan and CAA section 189(d) requirements for the 1997 24-
hour and annual PM<INF>2.5</INF> NAAQS in the San Joaquin Valley,
including the State's demonstration that the area would attain the 1997
24-hour PM<INF>2.5</INF> NAAQS by December 31, 2020. In this proposal,
the EPA is proposing action only on those portions of the SJV
PM<INF>2.5</INF> Plan that pertain to the 1997 24-hour PM<INF>2.5</INF>
NAAQS. The EPA is acting on the portions of the SJV PM<INF>2.5</INF>
Plan that pertain to the 1997 annual 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 must include
evidence that the state provided adequate public notice and an
opportunity for a public hearing consistent with the EPA's implementing
regulations in 40 CFR 51.102.
CAA section 110(k)(1)(B) requires the EPA to determine whether a
SIP submission is complete within 60 days of receipt. This section also
provides that any plan that the EPA has not affirmatively determined to
be complete or incomplete will become complete by operation of law six
months after the date of submission. The EPA's SIP completeness
criteria are found in 40 CFR part 51, Appendix V.
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 nonattainment
plan requirements in CAA section 189(b) and the CAA section 189(d)
requirements for the 1997 24-hour 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''); \31\ (iii)
numerous appendices to the 2018 PM<INF>2.5</INF> Plan; (iv)
[[Page 53153]]
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''); \32\ 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).\33\
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\31\ 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), and proposed action on those
portions pertaining to the 2012 annual PM<INF>2.5</INF> NAAQS (86 FR
49100). The EPA intends to take further action on those portions
that pertain to the 2012 annual PM<INF>2.5</INF> NAAQS in separate
rulemakings.
\32\ 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.
\33\ 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 24-hour 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''); \34\
(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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\34\ 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.\35\ CARB also provided public notice
and opportunity for public comment prior to its January 24, 2019 public
hearing on and adoption of the 2018 PM<INF>2.5</INF> Plan.\36\ 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.\37\ 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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\35\ 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.
\36\ 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.
\37\ 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.\38\ 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 the SJVUAPCD to identify
additional reductions from sources under District regulatory authority
as part of a comprehensive plan to attain all of the PM<INF>2.5</INF>
NAAQS in the San Joaquin Valley and to return to the Board with a
commitment to achieve additional emissions reductions from mobile
sources.\39\
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\38\ 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
(see, e.g., 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).
\39\ 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.\40\
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\40\ Letter dated May 9, 2019, from Richard Corey, Executive
Officer, CARB, to Mike Stoker, Regional Administrator, EPA Region 9.
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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.\41\ 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.\42\
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\41\ 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.
\42\ 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.\43\ 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.\44\
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.
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\43\ 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.
\44\ 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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III. Clean Air Act Requirements for PM[bdi2]<INF>.</INF>[bdi5] Serious
Area Plans and for Serious PM[bdi2]<INF>.</INF>[bdi5] Areas That Fail
To Attain
A. Requirements for PM2.5 Serious Area Plans
Upon reclassification of a Moderate nonattainment area as a Serious
nonattainment area under subpart 4 of part D, title I of the CAA, the
Act requires the state to make a SIP submission that addresses the
following Serious nonattainment area requirements: \45\
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\45\ 40 CFR 51.1003(b)(1); 81 FR 58010, 58074-58075 (August 24,
2016).
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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 (CAA section 172(c)(3));
[[Page 53154]]
2. Provisions to assure that the best available control measures
(BACM), including best available control technology (BACT), for the
control of direct PM<INF>2.5</INF> and PM<INF>2.5</INF> precursors
shall be implemented no later than four years after the area is
reclassified (CAA section 189(b)(1)(B));
3. A demonstration (including air quality modeling) that the plan
provides for attainment as expeditiously as practicable but no later
than the end of the tenth calendar year after designation as a
nonattainment area (i.e., December 31, 2015, for the San Joaquin Valley
for the 1997 PM<INF>2.5</INF> NAAQS);
4. Plan provisions that require RFP (CAA section 172(c)(2));
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 (CAA section 189(c));
6. 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
standard in the area (CAA section 189(e)); \46\
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\46\ As discussed in section IV.H, 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.
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7. Contingency measures to be implemented if the area fails to meet
RFP or to attain by the applicable attainment date (CAA section
172(c)(9)); and
8. A revision to the nonattainment new source review (NSR) program
to lower the applicable ``major stationary source'' \47\ thresholds
from 100 tons per year (tpy) to 70 tpy (CAA section 189(b)(3)).
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\47\ For any Serious area, the terms ``major source'' and
``major stationary source'' include any stationary source that emits
or has the potential to emit at least 70 tons per year of
PM<INF>2.5</INF>. CAA section 189(b)(3) and 40 CFR
51.165(a)(1)(iv)(A)(1)(vii) and (viii) (defining ``major stationary
source'' in serious PM<INF>2.5</INF> nonattainment areas).
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Serious area plans must also satisfy the requirements for Moderate
area plans in CAA section 189(a), to the extent the state has not
already met those requirements in the Moderate area plan submitted for
the area.\48\ In addition, the Serious area plan must meet the general
requirements applicable to all SIP submissions under section 110 of the
CAA, including the requirement to provide necessary assurances that the
implementing agencies have adequate personnel, funding, and authority
under section 110(a)(2)(E); and the requirements concerning enforcement
provisions in section 110(a)(2)(C).
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\48\ Because the EPA has not previously approved a SIP
submission for the San Joaquin Valley as meeting the subpart 4 RACM
Moderate area planning requirement under CAA section 189 for the
1997 24-hour 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 sections 189(b)
and 189(d).
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B. 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 percent per year from the most
recent emissions inventory for the area until attainment.\49\ 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.\50\
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\49\ CAA section 189(d), 40 CFR 51.1004(a)(3), 40 CFR
51.1010(c).
\50\ 81 FR 58010, 58098.
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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: \51\
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\51\ 40 CFR 51.1003(c)(1).
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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 Serious area plan control strategy that ensures that BACM,
including BACT, for the control of direct PM<INF>2.5</INF> and
PM<INF>2.5</INF> precursors are implemented in the area;
3. Additional measures (beyond those already adopted in previous
nonattainment plan SIP submissions for the area as RACM/RACT, BACM/
BACT, and most stringent measures (MSM) (if applicable)) \52\ that
provide for attainment of the NAAQS as expeditiously as practicable
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;
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\52\ MSM is applicable if the EPA has previously granted an
extension of the attainment date under CAA section 188(e) for the
nonattainment area and NAAQS at issue.
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4. A demonstration (including air quality modeling) that the plan
provides for attainment of the NAAQS at issue as expeditiously as
practicable;
5. Plan provisions that require RFP;
6. Quantitative milestones that the state is to meet every three
years until the area is redesignated attainment and that demonstrate
RFP toward attainment by the applicable date;
7. Contingency measures to be implemented if the state fails to
meet any requirement concerning RFP or quantitative milestones or to
attain the NAAQS at issue by the applicable attainment date; and
8. 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
NAAQS at issue in the area.\53\
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\53\ As discussed in section IV.H, 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.
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A state's section 189(d) plan submission 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.\54\
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\54\ 81 FR 84481, 84482.
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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.\55\ Because the EPA has not previously approved a SIP
submission
[[Page 53155]]
for the San Joaquin Valley as meeting the subpart 4 RACM Moderate area
planning requirements under CAA section 189 for the 1997 24-hour
PM<INF>2.5</INF> NAAQS, the EPA is evaluating relevant portions of the
SJV PM<INF>2.5</INF> Plan for compliance with this requirement. In
addition, as discussed above, the EPA has not previously approved a SIP
submission for the San Joaquin Valley as meeting the Serious area
planning requirements under CAA section 189(b)(1) for the 1997 24-hour
PM<INF>2.5</INF> NAAQS. Some Serious area planning requirements operate
on a timeline that is based on the outermost statutory Serious area
attainment date of the end of the tenth calendar year following the
area's designation to nonattainment. Because section 189(d) requires a
state to address any applicable Serious area requirements that the
state has not already met in the area, and the section 189(d)
obligations do not come into effect until an area has failed to attain
the NAAQS by the Serious area attainment date, the EPA proposes that it
should evaluate any previously unmet Serious area planning obligations
based on the current, applicable attainment date appropriate under
section 189(d), and not the original Serious area attainment date.
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\55\ 81 FR 58010, 58098.
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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''); \56\ (2) ``State
Implementation Plans; General Preamble for the Implementation of Title
I of the Clean Air Act Amendments of 1990; Supplemental'' (``General
Preamble Supplement''); \57\ 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'').\58\ 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> NAAQS.\59\ 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.
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\56\ 57 FR 13498 (April 16, 1992).
\57\ 57 FR 18070 (April 28, 1992).
\58\ 59 FR 41998 (August 16, 1994).
\59\ 81 FR 58010.
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IV. Review of the San Joaquin Valley PM[bdi2]<INF>.</INF>[bdi5] Plan
for the 1997 24-Hour PM[bdi2]<INF>.</INF>[bdi5] NAAQS
The EPA is evaluating the SJV PM<INF>2.5</INF> Plan against the
Serious area requirements for the 1997 24-hour PM<INF>2.5</INF> NAAQS
and the section 189(d) requirements for the 1997 24-hour
PM<INF>2.5</INF> NAAQS, as laid out in section III of this proposal.
Many requirements for both a Serious area plan and a section 189(d)
plan are structured around the relevant statutory attainment date. The
latest statutory Serious area attainment date for the San Joaquin
Valley area was December 31, 2015.\60\ On November 23, 2016, the EPA
determined that the area failed to attain by the Serious area
attainment date.
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\60\ As discussed in section I.B, California submitted its
Serious area plan for the 1997 24-hour PM<INF>2.5</INF> NAAQS in two
submissions dated June 25, 2015 and August 13, 2015, including a
request under section 188(e) to extend the attainment date for the
1997 24-hour PM<INF>2.5</INF> NAAQS by three years (to December 31,
2018). On October 6, 2016, the EPA denied the request for an
extension, but did not finalize action on the Serious area plan
submissions. Accordingly, the Serious area attainment date remained
unchanged: As expeditiously as practicable but no later than
December 31, 2015.
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For the purposes of the section 189(d) requirements, the attainment
date is the date by which a state can attain the NAAQS as expeditiously
as practicable, but no later than five years from the publication date
of the final determination of failure to attain.\61\ As discussed in
section IV.D, the SJV PM<INF>2.5</INF> Plan projected that attainment
could be achieved in fewer than five years, i.e., by December 31, 2020.
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\61\ CAA section 179(d)(3); 81 FR 84481, 84482. The
determination of failure to attain published on November 23, 2016.
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When the State submitted the SJV PM<INF>2.5</INF> Plan in 2019, the
State withdrew its previous Serious area plan that it had developed to
meet the December 31, 2015 Serious area attainment date. Because the
State submitted the SJV PM<INF>2.5</INF> Plan after the EPA's finding
that the area had failed to attain by the applicable Serious area
attainment date, the State could not demonstrate in the SJV
PM<INF>2.5</INF> Plan that the area would attain by the Serious area
attainment date, nor could it address other requirements based on this
attainment date, such as RFP and quantitative milestones, because many
of the relevant dates had already passed. As described in section III
of this document, in a section 189(d) plan, a state must address any
statutory requirements applicable to Moderate and Serious nonattainment
area plans to the extent that it has not already met those
requirements, but the EPA believes that it should base this evaluation
on the current applicable attainment date under section 189(d). For
example, it would be illogical to require a state to submit a Serious
area modeled attainment demonstration that provided for attainment by
December 31, 2015, after the EPA has already determined based on
monitoring data that the state failed to attain by such date.
For the purposes of our evaluation of the Serious area plan
requirements, although the State is required to submit a Serious area
plan, and it must structure such a plan based on the Serious area
attainment date, it would serve no purpose to evaluate the SJV
PM<INF>2.5</INF> Plan against the now-passed Serious area attainment
date by which the area has already failed to attain. For example, RFP
and quantitative milestones normally are dependent upon the attainment
date. Accordingly, because the State must still meet all Serious area
plan requirements, even if doing so later in conjunction with the
section 189(d) plan and its later attainment date, we will evaluate the
State's compliance with the Serious area plan requirements in light of
the later section 189(d) attainment date, as appropriate. Where the
State in the SJV PM<INF>2.5</INF> Plan applies the section 189(d)
attainment date to a Serious area requirement, we will note the
statutory Serious area timeline and accept the submission in
fulfillment of the State's Serious area plan obligation, but evaluate
the submission in light of the section 189(d) attainment date.
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.\62\ The EPA has also issued guidance concerning emissions
[[Page 53156]]
inventories for PM<INF>2.5</INF> nonattainment areas.\63\
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\62\ Id. at 58098-58099.
\63\ ``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 <a href="https://www.epa.gov/air-emissions-inventories/air-emissions-inventory-guidance-implementation-ozone-and-particulate">https://www.epa.gov/air-emissions-inventories/air-emissions-inventory-guidance-implementation-ozone-and-particulate</a>.
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The base year emissions inventory for a Serious area attainment
plan or a CAA section 189(d) plan must 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,\64\ and emissions of all chemical precursors to the
formation of secondary PM<INF>2.5</INF>, i.e., nitrogen oxides
(NO<INF>X</INF>), sulfur dioxide (SO<INF>2</INF>), volatile organic
compounds (VOC), and ammonia.\65\
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\64\ 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.
\65\ 40 CFR 51.1008(b)(1) and (c)(1).
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The emissions inventory base year for a Serious area attainment
plan must be one of the three years for which monitoring data were used
to reclassify the area to Serious, or another technically appropriate
year justified by the state in its Serious area SIP submission.\66\ 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 the EPA used monitored data 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.\67\
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\66\ 40 CFR 51.1008(b)(1).
\67\ 40 CFR 51.1008(c)(1).
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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 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.\68\ Following CARB's submission of the Plan, the EPA
approved EMFAC2017, the latest revision to this mobile source emissions
model. 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.\69\ \70\
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\68\ 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.
\69\ 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 emissions tests
results. 76 FR 6328 (February 4, 2011). CARB used the revised 2011
AP-42 methodology in developing on-road mobile source emissions; see
<a href="https://www.arb.ca.gov/ei/areasrc/fullpdf/full7-9_2016.pdf">https://www.arb.ca.gov/ei/areasrc/fullpdf/full7-9_2016.pdf</a>.
\70\ AP-42 has been published since 1972 as the primary source
of the EPA's emission factor information and is available at <a href="https://www.epa.gov/air-emissions-factors-and-quantification/ap-42-compilation-air-emissions-factors">https://www.epa.gov/air-emissions-factors-and-quantification/ap-42-compilation-air-emissions-factors</a>. 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.
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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.\71\ These future emissions projections are
necessary components of the attainment demonstrations required under
CAA sections 189(b)(1) and 189(d) and the demonstration of RFP required
under section 172(c)(2).\72\ 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 state calculated the
emissions projections. Where a state chooses to allow new major
stationary sources or major modifications to use emissions 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.\73\
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\71\ 40 CFR 51.1008 and 51.1012. See also Emissions Inventory
Guidance, section 3 (``SIP Inventory Requirements and
Recommendations'').
\72\ 40 CFR 51.1004, 51.1008, 51.1011, and 51.1012.
\73\ 40 CFR 51.165(a)(3)(ii)(C)(1).
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2. Summary of the State's Submission
The State included 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>,\74\ VOC,\75\ and ammonia) and the
documentation for the inventories for the San Joaquin Valley
PM<INF>2.5</INF> nonattainment area in Appendix B (``Emissions
Inventory'') and Appendix I (``New Source Review and Emission Reduction
Credits'') of the 2018 PM<INF>2.5</INF> Plan.
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\74\ 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
document.
\75\ 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 document.
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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.\76\
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\76\ 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.
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The Plan includes winter (24-hour) average and annual average daily
emissions inventories for the 2013 base year, which CARB derived 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.\77\ In this
proposal, we are proposing action on those winter average and annual
average emissions inventories necessary to support the Serious area and
CAA section 189(d) nonattainment plans for the 1997 24-
[[Page 53157]]
hour 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 emissions inventories for 2018 and 2019 to
support the five percent annual emissions reduction demonstration as
required by CAA section 189(d). Each inventory includes emissions from
stationary, area, on-road, and non-road sources.
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\77\ 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 and future year inventories were estimated using the
California Emission Projection Analysis Model (CEPAM), 2016 SIP
Baseline Emission Projections, version 1.05.
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CARB developed the base year inventories for stationary sources
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.\78\ 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>.\79\ 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.\80\ Re-entrained paved
road dust emissions were calculated using a CARB methodology consistent
with the EPA's AP-42 road dust methodology.\81\
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\78\ 2018 PM<INF>2.5</INF> Plan, Appendix B, section B.2
(``Emissions Inventory Summary and Methodology'').
\79\ Id. at B-42 to B-44.
\80\ Id. at B-37.
\81\ Id. at B-28.
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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.\82\
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
projected 2025 emissions inventory.\83\ 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.\84\
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\82\ Id. at B-18 and B-19.
\83\ 2018 PM<INF>2.5</INF> Plan, Appendix I, I-1 to I-5.
\84\ Id. at tables I-1 to I-5.
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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)
----------------------------------------------------------------------------------------------------------------
Category Direct 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
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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 PM2.5
Category 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
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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 Review of the State's Submission
We have reviewed the emissions inventories in the SJV
PM<INF>2.5</INF> Plan that pertain to the 1997 24-hour PM<INF>2.5</INF>
NAAQS and the 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(b)(1), the 2013 base year is one
of the three years of monitored data with which the EPA reclassified
the San Joaquin Valley area to Serious. Furthermore, in accordance with
40 CFR 51.1008(c)(1), the 2013 base year is one of the three years of
monitored data with which the EPA determined 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
[[Page 53158]]
1997 24-hour PM<INF>2.5</INF> NAAQS.\85\ The 2013 base year emissions
inventories represent 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.
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\85\ 81 FR 84481, 84482.
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With respect to future year emissions projections, we have reviewed
the growth and control factors and find them acceptable and thus
conclude that the future baseline emissions projections, which reflect
ongoing emissions reductions from existing (i.e., ``baseline'') control
measures as discussed in section IV.C.2.a, in the SJV PM<INF>2.5</INF>
Plan reflect appropriate calculation methods and the latest planning
assumptions. Also, as a general matter, the EPA will approve a SIP
submission that takes emissions reduction credit for a control measure
only where the EPA has approved the measure as part of the SIP. Thus,
for example, to take credit for the emissions reductions from newly
adopted or amended District rules for stationary sources, the related
rules must be approved by the EPA into the SIP. Table 1 of the EPA's
``Technical Support Document, San Joaquin Valley PM<INF>2.5</INF> Plan
for the 1997 24-hour PM<INF>2.5</INF> NAAQS,'' August 2021 (``EPA's
1997 24-hour PM<INF>2.5</INF> TSD'') shows District rules with post-
2013 compliance dates that are reflected in the future year baseline
inventories, along with information on the EPA's approval of these
rules, and shows that stationary source emissions reductions assumed by
the SJV PM<INF>2.5</INF> Plan for future years are supported by rules
approved as part of the California SIP for the San Joaquin Valley. With
respect to mobile sources, the EPA has taken action in recent years to
approve CARB mobile source regulations into the state-wide portion of
the California SIP. We therefore find that the future year baseline
projections in the SJV PM<INF>2.5</INF> Plan are properly supported by
SIP-approved stationary and mobile source measures.\86\
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\86\ The baseline emissions projections in the 2018
PM<INF>2.5</INF> Plan assume implementation of CARB's Zero Emissions
Vehicle (ZEV) sales mandate and greenhouse gas (GHG) standards. On
September 27, 2019, the U.S. Department of Transportation and the
EPA (the Agencies) issued a notice of final rulemaking for the Safer
Affordable Fuel-Efficient (SAFE) Vehicles Rule Part One: One
National Program (SAFE I) that, among other things, withdrew the
EPA's 2013 waiver of preemption for the ZEV sales mandate and
vehicle GHG standards. 84 FR 51310. See also proposed SAFE rule at
83 FR 42986 (August 24, 2018). In response to SAFE I, CARB developed
EMFAC off-model adjustment factors to account for anticipated
changes in on-road emissions. On March 12, 2020, the EPA informed
CARB that the EPA considers these adjustment factors to be
acceptable for future use. See letter dated March 12, 2020 from
Elizabeth J. Adams, EPA Region IX, to Steven Cliff, CARB. On April
30, 2020 (85 FR 24174), the Agencies issued a notice of final
rulemaking titled: The Safer Affordable Fuel-Efficient (SAFE)
Vehicles Rule for Model Years 2021-2026 Passenger Cars and Light
Trucks (SAFE II), establishing the federal fuel economy and GHG
vehicle emissions standards based on the August 2018 SAFE proposal.
The effect of both SAFE final rules (SAFE I and SAFE II) on the on-
road vehicle mix in the San Joaquin Valley nonattainment area and on
the resulting vehicular emissions is expected to be minimal during
the timeframe addressed in this SIP revision. Therefore, we
anticipate the SAFE final rules would not materially change the
attainment, RFP, or five percent reductions demonstrations for the
1997 24-hour PM<INF>2.5</INF> NAAQS in the SJV PM<INF>2.5</INF>
Plan.
---------------------------------------------------------------------------
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 24-
hour PM<INF>2.5</INF> NAAQS as meeting the requirements of CAA section
172(c)(3) and 40 CFR 51.1008 for purposes of both the Serious area and
the CAA section 189(d) attainment plans. We are also proposing to find
that the forecasted inventories in the Plan for the years 2017, 2018,
2019, 2020, and 2023 provide an adequate basis for the BACM, RFP, and
the modeled attainment demonstration analyses in the SJV
PM<INF>2.5</INF> Plan.
B. PM<INF>2.5</INF> 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>.\87\ 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.\88\
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\87\ ``Air Quality Criteria for Particulate Matter'' (EPA/600/P-
99/002aF), EPA, October 2004, Chapter 3.
\88\ ``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.\89\ The provisions of 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.'' \90\ 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>.\91\ 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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\89\ 81 FR 58010, 58017-58020.
\90\ CAA section 302(g).
\91\ 81 FR 58010, 58015.
---------------------------------------------------------------------------
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, MSM, and new source review (NSR)). 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.\92\ 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,\93\ a
state may demonstrate in a SIP submission that control of a certain
precursor pollutant is not necessary because it does not contribute
significantly to ambient PM<INF>10</INF> levels in the nonattainment
area and is not needed for attainment.\94\
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\92\ Id. at 58018-58019.
\93\ General Preamble, 13539-13542.
\94\ 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).
---------------------------------------------------------------------------
Under the PM<INF>2.5</INF> SIP Requirements Rule, a state may elect
to submit to the
[[Page 53159]]
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
standard in the area.\95\ 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, then the state is not
required to control emissions of the relevant precursor from sources in
the attainment plan.\96\
---------------------------------------------------------------------------
\95\ 40 CFR 51.1006(a)(1).
\96\ Id.
---------------------------------------------------------------------------
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''),\97\ 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.\98\ The EPA's recommendations in the PM<INF>2.5</INF> Precursor
Guidance are generally consistent with those in the Draft
PM<INF>2.5</INF> Precursor Guidance, with some exceptions, including
that the EPA's recommended contribution threshold for the 24-hour
PM<INF>2.5</INF> NAAQS changed from 1.3 [micro]g/m\3\ in the draft
guidance to 1.5 [micro]g/m\3\ in the final guidance.\99\
---------------------------------------------------------------------------
\97\ ``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.
\98\ ``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.
\99\ For the 24-hour PM<INF>2.5</INF> NAAQS, the EPA generally
expects that a precursor demonstration showing that the air quality
impact of a given precursor at all relevant locations does not
exceed a contribution threshold of 1.5 [mu]g/m\3\ will be adequate
to exempt sources of that precursor from control requirements.
PM<INF>2.5</INF> Precursor Guidance, 17.
---------------------------------------------------------------------------
We are evaluating the 1997 24-hour PM<INF>2.5</INF> NAAQS portion
of the SJV PM<INF>2.5</INF> Plan in accordance with the presumption
embodied within subpart 4, that states address all PM<INF>2.5</INF>
precursors in the 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 and are not necessary for attainment. In reviewing
any determination by a 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 brief 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.\100\ CARB presents
additional modeling results 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 \101\ and further clarifications
in five email transmittals.\102\ 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.\103\
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\100\ 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'').
\101\ 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'').
\102\ 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'').
\103\ 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.
---------------------------------------------------------------------------
The 2018 PM<INF>2.5</INF> 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 emissions trends, the
appropriateness of future year versus base year sensitivity, available
emissions controls, and the severity of nonattainment.\104\ These
analyses led CARB 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.\105\ 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 February 2020
Precursor TSD'').
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\104\ PM<INF>2.5</INF> Precursor Guidance, 18-19 (consideration
of additional information), 31 (available emissions controls), and
35-36 (appropriateness of future year versus base year sensitivity).
\105\ 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>.
---------------------------------------------------------------------------
For direct PM<INF>2.5</INF> and NO<INF>X</INF>, CARB modeled the
sensitivity of ambient PM<INF>2.5</INF> in the San Joaquin Valley to a
30 percent reduction in anthropogenic emissions of each pollutant in
2013, 2020, and 2024.\106\ The State concluded that direct
PM<INF>2.5</INF> and NO<INF>X</INF> emissions reductions will continue
to have a significant impact on 24-hour PM<INF>2.5</INF> design values
in the San Joaquin Valley, with NO<INF>X</INF> reductions being
particularly important.\107\ Consistent with this conclusion, the State
focused the control strategy and attainment demonstration on these two
pollutants,
[[Page 53160]]
as described in section IV.C of this preamble.
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\106\ 2018 PM<INF>2.5</INF> Plan, Chapter 5, 5-7 to 5-8. CARB
modeled the effects of both NO<INF>X</INF> reductions and direct
PM<INF>2.5</INF> reductions but the direct PM<INF>2.5</INF> results
were used only as a point of comparison, as direct PM<INF>2.5</INF>
emissions must be regulated in all PM<INF>2.5</INF> nonattainment
areas.
\107\ Id. at 5-8; and 2018 PM<INF>2.5</INF> Plan, Appendix G, 2.
CARB presents its sensitivity analysis for emissions reductions in
direct PM<INF>2.5</INF> and NO<INF>X</INF> in the Plan's attainment
demonstration appendix. 2018 PM<INF>2.5</INF> Plan, Appendix K,
Table 47 (annual average design values) and Table 48 (24-hour
average design values).
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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 [micro]g/m\3\
from the Draft PM<INF>2.5</INF> Precursor Guidance, which was available
at the time the State developed the SIP.\108\ The contributions of
ammonia, SO<INF>X</INF>, and VOC were 5.2 [micro]g/m\3\, 1.6 [micro]g/
m\3\, and 6.2 [micro]g/m\3\, respectively. Given that these levels are
well above the EPA's 0.2 [micro]g/m\3\ recommended contribution
threshold, the State proceeded with a sensitivity-based analysis.
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\108\ 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.
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CARB'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.\109\
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\109\ This procedure is the procedure recommended by the EPA.
PM<INF>2.5</INF> Precursor Guidance, 37.
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We summarize the State's sensitivity-based analysis and additional
information in the sections that follow for ammonia, SO<INF>X</INF>,
and VOC.
a. Ammonia
For ammonia, the State compared the 24-hour precursor contributions
to 1.3 [micro]g/m\3\, the recommended contribution threshold in the
Draft PM<INF>2.5</INF> Precursor Guidance. For a modeled 30 percent
ammonia emissions reduction, the ambient PM<INF>2.5</INF> responses in
2013 ranged from 0.9 to 3.3 [micro]g/m\3\ across 15 monitoring sites,
with a majority of sites above the 1.3 [micro]g/m\3\ contribution
threshold (and also above the 1.5 [micro]g/m\3\ contribution threshold
in the final PM<INF>2.5</INF> Precursor Guidance). PM<INF>2.5</INF>
responses in 2020 ranged from 0.5 to 1.9 [micro]g/m\3\, with four sites
at or above the 1.3 [micro]g/m\3\ contribution threshold, including one
site above the 1.5 [micro]g/m\3\ contribution threshold in the final
PM<INF>2.5</INF> Precursor Guidance. In 2024, all modeled responses
were below both recommended contribution thresholds. For a modeled 70
percent ammonia emissions reduction, the ambient PM<INF>2.5</INF>
responses in 2013 ranged from 3.5 to 12.4 [micro]g/m\3\, with all
monitoring sites above the 1.3 [micro]g/m\3\ threshold (and above the
1.5 [micro]g/m\3\ threshold), the PM<INF>2.5</INF> responses in 2020
ranged from 1.6 to 6.4 [micro]g/m\3\, and the PM<INF>2.5</INF>
responses in 2024 ranged from 1.2 to 3.0 [micro]g/m\3\, with most sites
above both recommended thresholds. For further detail, please see the
EPA's February 2020 Precursor TSD, Table 2, and the 2018
PM<INF>2.5</INF> Plan, Appendix G, tables 2 through 7. In summary, for
a 30 percent ammonia reduction, a majority of sites have
PM<INF>2.5</INF> responses above the contribution threshold in the 2013
modeling, decreasing to a single site above the contribution threshold
for 2020, and no sites above the contribution threshold for 2024. For a
70 percent reduction, all sites are above the contribution threshold in
the 2013 and 2020 modeling, and a majority of sites are above the
contribution threshold in 2024.
The State based its ammonia precursor determination on the
sensitivity analysis for the future years, using a 30 percent ammonia
emissions reduction. These choices respectively reflect its assessment
of research studies and the Plan's projected emissions reductions, and
on its assessment of available emissions controls. As explained in the
PM<INF>2.5</INF> Precursor Guidance, precursor responses may be above
the recommended contribution threshold and yet not contribute
significantly to levels that exceed the standard in the area.
Therefore, as recommended by the EPA, the State considered additional
information to examine whether the identified PM<INF>2.5</INF>
responses constituted a significant contribution to ambient
PM<INF>2.5</INF> in the San Joaquin Valley. The additional information
included research studies, emissions trends, and information to support
the State's conclusion that a 30 percent ammonia emissions reduction
represented a reasonable upper bound on the ammonia emissions
reductions to model in estimating its contribution to ambient
PM<INF>2.5</INF> levels. We summarize this additional information below
and provide a more detailed evaluation in the EPA's February 2020
Precursor TSD.
The State describes previous research that supports its finding
that ammonium nitrate PM<INF>2.5</INF> formation is the San Joaquin
Valley is NO<INF>X</INF>-limited rather than ammonia-limited.\110\
Essentially, ammonia is so abundant in the San Joaquin Valley that even
with large ammonia emissions reductions there would still be enough
ammonia to combine with the available NO<INF>X</INF> to readily form
particulate ammonium nitrate. Therefore, ammonia emissions reductions
would lead to only small decreases in PM<INF>2.5</INF> concentrations.
In contrast, because emissions of NO<INF>X</INF> are less abundant in
the San Joaquin Valley (i.e., more limited relative to emissions of
ammonia after normalizing for their differing molecular weights), the
PM<INF>2.5</INF> concentrations in the atmosphere are more responsive
to reductions in NO<INF>X</INF> than to reductions of ammonia. Thus,
these analyses indicate that the area is NO<INF>X</INF>-limited.
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\110\ 2018 PM<INF>2.5</INF> Plan, Appendix G, 9-10; CARB Staff
Report, Appendix C, 12-15; and Attachment A to CARB's May 9, 2019
submittal letter.
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The State also points to the conclusions of a study conducted by
Lurmann et al., based on ambient measurements during the winter 2000-
2001 California Regional Particulate Air Quality Study intensive field
study.\111\ That study found that most areas of the San Joaquin Valley
were NO<INF>X</INF>-limited with respect to ammonium nitrate formation.
Since that time, large additional NO<INF>X</INF> emissions reductions
have occurred, which would increase the degree to which ammonium
nitrate formation in the San Joaquin Valley is NO<INF>X</INF>-limited.
Based on more recent aircraft-borne measurements during the 2013
DISCOVER-AQ campaign,\112\ the State similarly concluded that ammonium
nitrate formation is NO<INF>X</INF>-limited based on the large amount
of ``excess ammonia,'' which is defined as the amount of measured
ammonia left over if all the nitrate and sulfate present
[[Page 53161]]
were to combine with available ammonia to form particulate.\113\ The
CARB Staff Report describes these conclusions in more detail and lists
results from multiple other recent studies with similar
conclusions.\114\ Finally, in a supplemental submittal, CARB described
the results of two analyses confirming the likely underestimation of
ammonia emissions in the modeled emissions inventory inputs.\115\ CARB
compared CMAQ model predictions of ammonia with the 2013 DISCOVER-AQ
aircraft measurements and found ammonia was underpredicted, and noted
that this would result in the response to ammonia reductions being
overpredicted. CARB also compared 2017 satellite measurements of
ammonia with CMAQ model predictions and found that modeled ammonia
concentrations were half of the magnitude of the satellite observations
at some locations, and the modeled valley-wide average was about 25
percent less than observed. Because the modeling performs well for the
various PM<INF>2.5</INF> components, as well as for ozone and
NO<INF>2</INF>,\116\ the CARB finding of CMAQ model underpredictions
for ammonia is consistent with an underestimation of ammonia emissions
inventory input to the model.
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\111\ Frederick W. Lurmann, Steven G. Brown, Michael C.
McCarthy, and Paul T. Roberts, ``Processes Influencing Secondary
Aerosol Formation in the San Joaquin Valley during Winter,'' Journal
of the Air & Waste Management Association, (2006), 56:12, 1679-1693,
DOI: 10.1080/10473289.2006.10464573.
\112\ Deriving Information on Surface conditions from COlumn and
VERtically Resolved Observations Relevant to Air Quality,'' <a href="https://www.nasa.gov/mission_pages/discover-aq/index.html">https://www.nasa.gov/mission_pages/discover-aq/index.html</a>.
\113\ 2018 PM<INF>2.5</INF> Plan, Appendix G, Figure 2.
\114\ CARB Staff Report, Appendix C, 12.
\115\ CARB's April 26, 2021 Precursor Clarification.
\116\ EPA's February 2020 Modeling TSD, 21.
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Regarding emissions trends, the CARB Staff Report presents an
emissions inventory-based argument on the relative insensitivity of
PM<INF>2.5</INF> to ammonia reductions.\117\ CARB compared the size of
the ammonia and NO<INF>X</INF> emissions inventories in tons per day,
after normalizing for their differing molecular weights, and found that
ammonia was roughly three times as abundant as NO<INF>X</INF> in 2013
and is projected to be about six times as abundant in 2025, due to the
continuing decline in NO<INF>X</INF> emissions (while ammonia emissions
are generally constant into the future).\118\ While the State
recognized that this is only a ``first-level assessment,'' it provides
additional support for the State's conclusion that NO<INF>X</INF>, and
not ammonia, is the limiting precursor for ammonium nitrate formation,
and that the ammonium nitrate portion of ambient PM<INF>2.5</INF> would
be expected to be relatively insensitive to ammonia emissions
reductions. This is also consistent with the ammonia sensitivity
modeling for the San Joaquin Valley, which showed that PM<INF>2.5</INF>
concentrations will be less sensitive to ammonia reductions as
NO<INF>X</INF> emissions go down in the future (i.e., the
PM<INF>2.5</INF> impacts were much smaller in the 2020 and 2024 future
modeled cases compared to the 2013 base year).
---------------------------------------------------------------------------
\117\ CARB Staff Report, Appendix C, 15.
\118\ Annual average ammonia emissions are projected to decrease
4.6 tpd (1.4 percent) from 2013 to 2024. 2018 PM<INF>2.5</INF> Plan,
Appendix B, Table B-5.
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The State projected that NO<INF>X</INF> emissions in the San
Joaquin Valley would decrease by 36 percent from 2013 to 2020, and by
53 percent from 2013 to 2024, while ammonia emissions would remain
relatively flat, thereby increasing the relative abundance of
ammonia.\119\ Based on the Plan's emissions reduction projections
combined with the research study conclusions, the State relies on the
modeled responses for the future years, rather than the 2013 base year,
stating that the future year NO<INF>X</INF> emissions are more
representative of San Joaquin Valley emissions conditions.\120\ The
State references the Draft PM<INF>2.5</INF> Precursor Guidance, which
notes that it may be appropriate to model future conditions that are
more representative of current atmospheric conditions and those
conditions expected closer to the attainment date. The State concludes
that this in fact applies to the San Joaquin Valley.\121\
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\119\ 2018 PM<INF>2.5</INF> Plan, Appendix G, 8-9.
\120\ Id. at 9.
\121\ Id (referencing Draft PM<INF>2.5</INF> Precursor Guidance,
33). See also PM<INF>2.5</INF> Precursor Guidance, 35.
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With respect to the State's selection of 30 percent as an upper
bound on the ammonia reductions to model, the State described its
review of the most important ammonia source categories in the San
Joaquin Valley, existing control measures that affect ammonia emissions
from these sources, additional mitigation options for these sources,
and information provided in the PM<INF>2.5</INF> Precursor Guidance
about ammonia reductions achieved nationwide from 2011 to 2017.\122\
The primary sources of ammonia emissions identified in the 2018
PM<INF>2.5</INF> Plan are: (1) Confined animal facilities (CAFs); (2)
agricultural fertilizer; (3) biosolids, animal manure, and poultry
litter operations; and (4) organic material composting operations.\123\
CAFs are subject to District Rule 4570; biosolids, animal manure, and
poultry litter operations are subject to District Rule 4565; and
organic material composting operations are subject to District Rule
4566. Although these District rules explicitly apply only to VOC
emissions from these sources, the State concludes that these rules also
reduce ammonia emissions. Appendix C of the 2018 PM<INF>2.5</INF> Plan
cites several scientific studies that address the correlation between
VOC and ammonia emissions from these emissions sources.\124\ Based on
these evaluations, the State concludes that ammonia control measures
achieving even the low end of the range (30 percent) are not feasible
for implementation in the San Joaquin Valley and that it is therefore
reasonable to treat a 30 percent ammonia reduction as an upper bound
for modeling in the precursor demonstration.
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\122\ 2018 PM<INF>2.5</INF> Plan, Appendix G and Appendix C,
section C-25, and CARB's October 2019 Precursor Clarification.
\123\ 2018 PM<INF>2.5</INF> Plan, Appendix C, section C-25.
\124\ Id. at C-314 and following.
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In summary, the State's sensitivity analysis presents a range of
PM<INF>2.5</INF> responses to ammonia emissions reductions depending on
base year versus future year, and on the scale of emissions reductions
that may be possible. The Plan provides the State's bases for finding
that the future year sensitivity results better represent conditions in
the San Joaquin Valley than the 2013 base year and for finding a 30
percent ammonia reduction to be a reasonable upper bound for modeled
ammonia emissions reductions in assessing the ammonia contribution.
Based on these analyses, the State concludes that ammonia does not
contribute significantly to ambient PM<INF>2.5</INF> levels above the
1997 24-hour PM<INF>2.5</INF> NAAQS in the San Joaquin Valley.
b. SO<INF>X</INF>
For SO<INF>X</INF>, the State compared the 24-hour precursor
contributions to the recommended draft contribution threshold of 1.3
[micro]g/m\3\ in the Draft PM<INF>2.5</INF> Precursor Guidance. For
modeled SO<INF>X</INF> emissions reductions of 30 percent and 70
percent, the ambient PM<INF>2.5</INF> responses in 2013 ranged from -
1.4 to 0.5 [micro]g/m\3\ across 15 monitoring sites, which all fall
below the 1.3 [micro]g/m\3\ draft contribution threshold, and hence
also below the contribution threshold of 1.5 [micro]g/m\3\ in the final
version of the PM<INF>2.5</INF> Precursor Guidance.\125\ The response
was below zero at most monitoring sites, indicating an increase, rather
than a decrease, in ambient PM<INF>2.5</INF> in response to
SO<INF>X</INF> emissions reductions (i.e., a disbenefit). Only the
Stockton and Manteca sites had slightly positive responses to 30
percent and 70 percent emissions reductions, and the Tranquillity site
also had a slightly positive response only to a 30 percent reduction.
For the 15 sites, in 2020, the responses to 30 percent and 70 percent
emissions reductions ranged from -1.3 [micro]g/m\3\ to
[[Page 53162]]
0.5 [micro]g/m\3\ while for 2024, the responses ranged from -1.1
[micro]g/m\3\ to 0.6 [micro]g/m\3\; these are also all below the
contribution threshold, with most sites showing a disbenefit from
SO<INF>X</INF> reductions.\126\ The Stockton, Manteca, and Tranquillity
sites showed the same pattern of slight benefits as for 2013.\127\ For
further detail, please see the EPA's February 2020 Precursor TSD, Table
3 and the 2018 PM<INF>2.5</INF> Plan, Appendix G, tables 8 and 9 and
Appendix K, tables 46, 48, and 50.
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\125\ 2018 PM<INF>2.5</INF> Plan, Appendix G, Table 8 and Table
9.
\126\ CARB's September 2019 Precursor Clarification, 2020
analysis tables 15 and 16, and 2024 analysis tables 15 and 16.
\127\ 2018 PM<INF>2.5</INF> Plan, Appendix K, Table 48 and Table
50.
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CARB also included additional information regarding emissions
trends and an evaluation of the SO<INF>X</INF> emissions reduction
disbenefit. We summarize this additional information below and provide
a more detailed evaluation in the EPA's February 2020 Precursor TSD.
In terms of emissions trends, the State found that SO<INF>X</INF>
emissions decreased from 2013 to 2014 and then were expected to very
gradually rise to 7.8 tpd in 2020 and 8.0 tpd in 2024.\128\ Given that
projected SO<INF>X</INF> emissions are very similar in 2020 and 2024,
the State concluded that the 2020 and 2024 sensitivity results were
redundant. Comparing the ambient responses in 2013 and 2024, the State
found that the responses were slightly less negative or, for a small
number of sites, slightly higher in 2024, but still no more than 0.6
[micro]g/m\3\ in response to a 70 percent SO<INF>X</INF> emissions
reduction.\129\ This supports the State's conclusion as to the overall
disbenefit of reducing SO<INF>X</INF> emissions.
---------------------------------------------------------------------------
\128\ 2018 PM<INF>2.5</INF> Plan, Appendix G, Figure 4.
\129\ CARB's September 2019 Precursor Clarification, 2013
analysis Table 16 and 2024 analysis Table 16.
---------------------------------------------------------------------------
To explain the SO<INF>X</INF> emissions reduction disbenefit that
is observed in some cases, CARB refers to the non-linearity of
inorganic aerosol thermodynamics, as described in a study by West et
al.\130\ That paper discusses how, under certain conditions, reducing
SO<INF>X</INF> could free ammonia to combine with nitrate, increasing
overall PM<INF>2.5</INF> mass. To investigate this issue further, CARB
conducted simulations with the ISORROPIA inorganic aerosol
thermodynamic equilibrium model used within the CMAQ model and provided
clarifications to the EPA.\131\ In essence, CARB states that for some
conditions typical of San Joaquin Valley, ISORROPIA switches to a
different chemical regime in which the disbenefit occurs. CARB states
that it is not known how well this model behavior reflects the actual
atmosphere, but CARB accepts the results because it is a well-known and
widely used chemical model.
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\130\ 2018 PM<INF>2.5</INF> Plan, Appendix K, section 5.6
(``PM<INF>2.5</INF> Precursor Sensitivity Analysis''); and West,
J.J., Ansari, A.S., Pandis, S.N., 1999, Marginal PM<INF>2.5</INF>:
Nonlinear aerosol mass response to sulfate reductions in the eastern
United States, Journal of the Air & Waste Management Association,
49, 1415-1424. <a href="https://doi.org/10.1080/10473289.1999.10463973">https://doi.org/10.1080/10473289.1999.10463973</a>.
\131\ CARB's June 2019 Precursor Clarification.
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Based on the small and mostly negative modeled response of ambient
PM<INF>2.5</INF> to SO<INF>X</INF> emissions reductions, and based on
its scientific understanding of sulfate interactions with other
molecules in the air, the State concludes that SO<INF>X</INF> does not
contribute significantly to ambient PM<INF>2.5</INF> levels that exceed
the 1997 24-hour PM<INF>2.5</INF> NAAQS in the San Joaquin Valley.
c. VOC
For VOC, CARB compared the 24-hour precursor contributions to the
EPA's recommended draft contribution threshold of 1.3 [micro]g/m\3\.
For a modeled 30 percent VOC emissions reduction, the ambient
PM<INF>2.5</INF> responses in 2013 ranged from 0.1 to 1.9 [micro]g/m\3\
across 15 monitoring sites, with two sites above the 1.3 [micro]g/m\3\
draft contribution threshold.\132\ \133\ The 2020 responses ranged from
-0.1 to 0.6 [micro]g/m\3\, with all monitoring sites below the 1.3
[micro]g/m\3\ draft contribution threshold, and hence also below the
contribution threshold of 1.5 [micro]g/m\3\ that was finalized in the
final PM<INF>2.5</INF> Precursor Guidance. The 2024 responses ranged
from -0.4 to 0.0 [micro]g/m\3\, with all monitoring sites below both
the draft and final contribution thresholds. For a 70 percent VOC
emissions reduction, the PM<INF>2.5</INF> responses in 2013 ranged from
0.2 to 4.8 [micro]g/m\3\, including responses above both contribution
thresholds at a majority of sites. The 2020 response ranged from -0.2
to 1.5 [micro]g/m\3\, with one site at the final contribution
threshold. The 2024 response ranged from -1.0 to 0.0 [micro]g/m\3\ with
monitoring sites below both the contribution thresholds. In other
words, in response to either a 30 percent or a 70 percent reduction in
VOC emissions, CARB models a decrease in ambient PM<INF>2.5</INF>
levels at all sites for 2013, whereas for 2020, there were just small
decreases in ambient PM<INF>2.5</INF> levels at most sites and an
increase at one site, and for 2024 there were increases in
PM<INF>2.5</INF> at all sites, i.e., a disbenefit. For further detail,
please see the EPA's February 2020 Precursor TSD, Table 4, and the 2018
PM<INF>2.5</INF> Plan, Appendix G, tables 10 through 15.
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\132\ 2018 PM<INF>2.5</INF> Plan, Appendix G, Table 10.
\133\ We note that one site (Visalia) has a modeled response
above the EPA's final recommended contribution threshold of 1.5
[micro]g/m\3\ and one additional site (Bakersfield-California
Avenue) has a modeled response below the 1.5 [micro]g/m\3\ threshold
but above the EPA's draft threshold of 1.3 [micro]g/m\3\.
---------------------------------------------------------------------------
CARB then considered additional information to assess whether these
PM<INF>2.5</INF> responses constituted a significant contribution to
ambient PM<INF>2.5</INF> in the San Joaquin Valley, including emissions
trends and an assessment of the modeled disbenefit of VOC emissions
reductions. Regarding emissions trends, CARB found that VOC emissions
would decrease approximately 30 tpd (or 9 percent) from 2013 to 2024,
with approximately 28 out of the 30 tpd reduction taking place by
2020.\134\ The State concludes that the formation of ambient
PM<INF>2.5</INF> from VOC may therefore differ in base and future years
and that the sensitivity analysis for 2013 is not representative of
current or future conditions.
---------------------------------------------------------------------------
\134\ 2018 PM<INF>2.5</INF> Plan, Appendix G, 19 and Figure 5.
---------------------------------------------------------------------------
CARB explained the modeled disbenefit of VOC reductions as follows:
Emissions of VOC and NO<INF>X</INF> react in the atmosphere to form
organic nitrate species, such as peroxyacetyl nitrate (PAN), meaning
that some portion of the NO<INF>X</INF> emissions is not available to
react with ammonia to form ammonium nitrate. In other words, VOC
emissions are a ``sink'' for NO<INF>X</INF> emissions. Reducing VOC
emissions therefore reduces the formation of organic nitrates, so the
sink is smaller and nitrate molecules are freed to react with ammonia
to form particulate ammonium nitrate.\135\ The State further explored
the VOC disbenefit based on a 2016 CARB modeling assessment provided in
Appendix A (``Air Quality Modeling'') of the ``2016 Moderate Area Plan
for the 2012 PM<INF>2.5</INF> Standard'' for the San Joaquin Valley
(``2016 PM<INF>2.5</INF> Plan''), which CARB submitted to the EPA as a
SIP revision on May 10, 2019.\136\
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\135\ 2018 PM<INF>2.5</INF> Plan, Appendix K, 72 (citing Meng,
Z., D. Dabdub, D., Seinfeld, J.H., Chemical Coupling Between
Atmospheric Ozone and Particulate Matter, Science 277, 116 (1997).
DOI: 10.1126/science.277.5322.116).
\136\ 2016 PM<INF>2.5</INF> Plan, Appendix A, A-57. See also
2018 PM<INF>2.5</INF> Plan, Appendix K, section 5.6
(``PM<INF>2.5</INF> Precursor Sensitivity Analysis''), 71-72.
---------------------------------------------------------------------------
Based on its sensitivity-based analysis of VOC emissions
reductions, VOC emissions trends, and the scientific understanding of
VOC chemistry in the San Joaquin Valley, CARB concludes that VOC
emissions do not contribute significantly to PM<INF>2.5</INF> levels
that exceed the 1997 24-hour PM<INF>2.5</INF> NAAQS in the San Joaquin
Valley.
[[Page 53163]]
3. The EPA's Review of the State's Submission
The EPA has evaluated the State's precursor demonstration
consistent with the PM<INF>2.5</INF> SIP Requirements Rule and the
recommendations in the PM<INF>2.5</INF> Precursor Guidance. Based on
this evaluation, the EPA agrees that NO<INF>X</INF> emissions
contribute significantly to ambient PM<INF>2.5</INF> levels that exceed
the 1997 24-hour PM<INF>2.5</INF> NAAQS in the San Joaquin Valley and
that NO<INF>X</INF> emissions sources, therefore, remain subject to
control requirements under subparts 1 and 4 of the part D, title I of
the Act. For the reasons provided below, the EPA proposes to approve
the State's demonstration that ammonia, SO<INF>X</INF>, and VOC
emissions do not contribute significantly to ambient PM<INF>2.5</INF>
levels that exceed the 1997 24-hour PM<INF>2.5</INF> NAAQS in the San
Joaquin Valley.
Regarding the State's analytical approach, the EPA finds that the
State based its analyses on the latest available data and studies
concerning ambient PM<INF>2.5</INF> formation in the San Joaquin Valley
from precursor emissions. Regarding the required concentration-based
analysis, the EPA finds that the State assessed the absolute annual
average contribution of each precursor in ambient PM<INF>2.5</INF>
(i.e., in 2015). On the basis of the absolute concentrations being well
above the EPA's recommended contribution thresholds for both the 24-
hour and annual average NAAQS, the State proceeded with its
sensitivity-based analysis, which is the recommended sequence under the
final PM<INF>2.5</INF> Precursor Guidance.\137\
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\137\ For further discussion of the EPA's evaluation of the
State's concentration-based analysis, see the EPA's February 2020
Precursor TSD, sections entitled ``Concentration-based analysis''
within the EPA's evaluation for each of ammonia, SO<INF>X</INF>, and
VOC.
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With respect to the sensitivity-based analysis, we find that the
State performed its analyses following the steps of the EPA's
recommended approach--i.e., for each modeled year and percent precursor
emissions reduction, the State estimated the ambient PM<INF>2.5</INF>
response using the procedure recommended in the PM<INF>2.5</INF>
Precursor Guidance and compared the result to the recommended
contribution threshold. The EPA also finds that the performance of the
photochemical model was adequate for use in estimating the ambient
PM<INF>2.5</INF> responses, as discussed in section J (``Air Quality
Model Performance'') of the EPA's ``Technical Support Document, EPA
Evaluation of Air Quality Modeling, San Joaquin Valley PM<INF>2.5</INF>
Plan for the 2006 PM<INF>2.5</INF> NAAQS,'' February 2020 (``EPA's
February 2020 Modeling TSD''). The State considered the EPA's
recommended range of emissions reductions (30 percent to 70 percent)
for the 2013 base year, the projected 2020 attainment year for the 1997
24-hour PM<INF>2.5</INF> NAAQS, and the projected 2024 attainment year
for the 2006 PM<INF>2.5</INF> NAAQS, and quantified the estimated
response of ambient PM<INF>2.5</INF> concentrations to precursor
emissions changes for the first time in a PM<INF>2.5</INF> SIP
submission for the San Joaquin Valley. The EPA finds that such
quantification and CARB's consideration of additional information
provide an informed basis on which to make a determination as to
whether ammonia, SO<INF>X</INF>, and VOC do or do not contribute
significantly to ambient PM<INF>2.5</INF> levels that exceed the 1997
24-hour PM<INF>2.5</INF> NAAQS in the San Joaquin Valley.\138\
Therefore, we turn to our evaluation of the State's determination for
each of these three precursor pollutants.
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\138\ The State did not evaluate the 2015 Serious area
attainment year. Because the year has passed and the area failed to
attain by the Serious area attainment date, we will evaluate the
precursor analysis for the Serious area plan based on the current
section 189(d) projected attainment date of December 31, 2020.
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a. Ammonia
For ammonia, as detailed above, CARB estimated the ambient
PM<INF>2.5</INF> response to both a 30 percent and a 70 percent
emissions reduction. We find that it was appropriate for the State to
consider additional information to interpret those results to determine
whether the ammonia contribution is significant. The primary conclusion
demonstrated by the State's analysis of additional information is that
ammonium nitrate formation is NO<INF>X</INF>-limited. As discussed in
more detail below, we agree with this conclusion. We have evaluated
CARB's determination that a projected future year is more
representative of conditions in the San Joaquin Valley for sensitivity-
based analyses and that 30 percent is a reasonable upper bound for
ammonia emissions reductions to assess the precursor contribution, as
discussed below.
The State provided ample information from scientific studies based
on ambient measurements to help assess the estimated sensitivity of
ambient PM<INF>2.5</INF> to ammonia reductions. Conclusions based on
ambient data are particularly relevant because they provide direct
evidence of the chemical state of the atmosphere and are not dependent
on modeled estimates of emissions or modeled ambient PM<INF>2.5</INF>
concentrations. Measurements represent the ``real world'' result of the
pollutants' differing geographic distributions, the various
meteorological and chemical factors influencing their conversion to
particulate, and their removal from the atmosphere by deposition and
other processes. The observed abundance of ammonia relative to nitric
acid, and the positive amount of chemically excess ammonia, both
provide strong evidence that ammonia is not the limiting pollutant for
particulate ammonium nitrate formation. They also support the State's
conclusion that PM<INF>2.5</INF> concentrations are insensitive to
ammonia emissions reductions.
The relative amount of ammonia and NO<INF>X</INF> emissions is one
of the most critical factors in determining the sensitivity of ambient
PM<INF>2.5</INF> to ammonia reductions. We note that the model response
to precursor reductions may be unrealistically large due to the
underestimation of ammonia emissions and therefore of the ratio of
ammonia to NO<INF>X</INF> emissions. There is evidence that ammonia
emissions may be underestimated based on direct measurements of ammonia
emissions flux during two measurement campaigns, as discussed in the
EPA's February 2020 Precursor TSD. If ammonia emissions were higher in
the modeling, then ammonia would be more abundant relative to nitrate
and particulate nitrate formation would be more NO<INF>X</INF>-limited
and less sensitive to ammonia reductions. This would make the model
response more consistent with the ambient measurement studies, which
suggest a very low sensitivity to ammonia. This evidence indicates that
ammonia contribution to PM<INF>2.5</INF> levels above the standard is
likely to be less than estimated by the State's modeling in each of the
three years. In comparison to the 2013 and 2020 modeling, the modeling
for the year 2024 incorporates lower NO<INF>X</INF> emissions and so
has a larger abundance of ammonia relative to nitrate, more similar to
the studies' ambient measurements. Thus, the 2024 response to ammonia
reductions is likely to be more reliable than the 2013 and 2020
responses and appears to be more representative of current atmospheric
conditions despite the use of emissions projections for a future year.
The relative sizes of the ammonia and NO<INF>X</INF> precursor
emissions inventories after accounting for their differing molecular
weights are a rough indicator of which pollutant is the limiting
pollutant for production of ammonium nitrate because ammonium nitrate
forms from a one-to-one ratio of molecules derived from each precursor
(i.e., one ammonium nitrate forms from one
[[Page 53164]]
ammonium and one nitrate). However, unlike measurements and
photochemical modeling, a simple emissions ratio does not account for
various processes mentioned above; it assumes all the emitted molecules
find one another and react. The State found ammonia to be roughly three
times as abundant as NO<INF>X</INF> in 2013 after accounting for their
differing molecular weights, and even more abundant in future years.
The EPA repeated the exercise to account for SO<INF>X</INF> and found
that the ratio of total ammonia to the ammonia needed to react with
both nitrate and sulfate ranged from 2.7 in 2013 to 5.6 in 2028. These
results are approximately the same as the CARB NO<INF>X</INF>-only
results because SO<INF>X</INF> emissions are very small relative to
NO<INF>X</INF> and ammonia emissions (e.g., in 2013, winter daily
emissions were 8.4 tpd of SO<INF>X</INF> versus 300.5 tpd of
NO<INF>X</INF> and 309.8 tpd of ammonia).\139\ These observations
support the State's finding that PM<INF>2.5</INF> is expected to be
relatively insensitive to ammonia reductions, though they are not
definitive on their own.
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\139\ 2018 PM<INF>2.5</INF> Plan, Appendix B, tables B-2, B-3,
and B-4.
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The State also points to large decreases or projected decreases in
NO<INF>X</INF> emissions in the San Joaquin Valley from 2013 to 2024,
including a 36 percent reduction from baseline measures by 2020, and a
53 percent reduction by 2024, while CARB projects that ammonia
emissions will remain roughly constant (i.e., decreasing 1-2 percent).
In conjunction with the ambient evidence that ammonia is already
chemically overabundant relative to NO<INF>X</INF> in the San Joaquin
Valley, this indicates that the overabundance will become even greater
in the future, and thus ambient PM<INF>2.5</INF> is expected to be even
less responsive to ammonia reductions. This adds conservatism to the
State's conclusions about ammonia sensitivity based on the scientific
studies.
While the base year for an attainment plan for a given
nonattainment area is generally more representative of current
conditions, there can be situations in which is it more appropriate to
use future conditions representative of when sources will operate, and
the EPA believes that states may use either a base year or a future
year for modeling an ambient PM<INF>2.5</INF> response to precursor
emissions reductions, provided the state explains how the choice of
analysis year and associated assumptions are appropriate.\140\ The 2013
modeled responses cannot be considered current at the present time, in
comparison to the 2020 results. Large NO<INF>X</INF> emissions
reductions have occurred from 2013-2020 and are projected to continue
to occur on through 2024, continuing to decrease the ratio of
NO<INF>X</INF> to ammonia. In light of this ongoing trend, and the
ambient data indicating that models underestimate ammonia, the EPA
believes that future year results, which more accurately reflect the
expected NO<INF>X</INF> to ammonia ratio, will continue to be
representative, unlike the 2013 base year. These reductions are the
result of regulations put in place by past air quality planning
decisions and they will occur regardless of the actions that are being
proposed herein. In assessing the effect of potential ammonia
reductions, the EPA believes it is reasonable to account for these
NO<INF>X</INF> reductions. In addition, as noted above, the greater
abundance of ammonia relative to NO<INF>X</INF> in the 2024 year
modeling is more consistent with recent ambient measurements, which
suggest that the 2024 responses are more representative of current
atmospheric conditions than the other model years for assessing
sensitivity to ammonia reductions. Therefore, in consideration of the
scientific studies and emissions trends, including the projected large
amount of NO<INF>X</INF> emissions reductions through the attainment
period, the EPA agrees that use of a future year is appropriate. Given
the available research and ambient data, we conclude that the modeled
2024 year is the most representative of conditions in the San Joaquin
Valley.
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\140\ PM<INF>2.5</INF> Precursor Guidance, 35-36.
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Even if we were to set aside the more representative 2024 modeling,
in the 2020 modeled responses, only the Bakersfield-Planz site is above
the contribution threshold, at 1.9 [micro]g/m\3\. A single value above
the threshold is not determinative, particularly in light of the
additional information provided above, indicating that the modeled
values overestimate the contribution of ammonia to ambient
PM<INF>2.5</INF> levels, and that the trend continues toward less
contribution in the future as the ratio of NO<INF>X</INF> to ammonia
continues to drop. Moreover, the monitored 2020 design value is
attaining the 1997 24-hour PM<INF>2.5</INF> NAAQS because, as discussed
above and in section V of this proposal, at the current time there are
not PM<INF>2.5</INF> levels above the NAAQS. This is further evidence
that the single 2020 modeled response above the contribution threshold
is not a significant contribution to PM<INF>2.5</INF> levels in excess
of the NAAQS, even if the 2020 modeling were considered representative.
In the context of interpreting the full set of modeling results for
ammonia emissions reductions, the EPA also considered the State's
conclusion that the absence of available ammonia controls for sources
in the San Joaquin Valley supports its decision to treat a 30 percent
reduction as a reasonable upper bound on the ammonia emissions
reductions to model in estimating the precursor contribution. As the
State correctly notes, the 30 percent to 70 percent range recommended
by the EPA is based on historical NO<INF>X</INF> and SO<INF>X</INF>
emissions reductions, and changes in ammonia emissions levels
nationally from 2011 to 2017 ranged from a 9 percent decrease to a 6
percent increase.\141\ The State's descriptions of past research relied
upon to develop existing rules that apply to ammonia emissions sources,
as well as ongoing research, show that it has considered the
availability of ammonia controls both in the past and present context,
and that the State has a basis for its conclusion that 30 percent is a
reasonable upper bound on achievable reductions for ammonia.
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\141\ Id. at 30, Table 2.
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In sum, we find that the State quantified the sensitivity of
ambient PM<INF>2.5</INF> levels to reductions in ammonia using
appropriate modeling techniques that performed well, and that the
State's analysis and use of future year sensitivity data, both 2020 and
2024, is well-supported. We also find that the State adequately
documented its basis for using a 30 percent reduction in ammonia
emissions as an upper bound in the modeling to assess ambient
sensitivity to ammonia emissions reductions. Based on these
considerations, the EPA proposes to approve the State's demonstration
that ammonia emissions do not contribute significantly to ambient
PM<INF>2.5</INF> levels that exceed the 1997 24-hour PM<INF>2.5</INF>
NAAQS in the San Joaquin Valley.
b. SO<INF>X</INF>
For SO<INF>X</INF>, the State found that the ambient
PM<INF>2.5</INF> responses to SO<INF>X</INF> emissions reductions were
below the EPA's recommended contribution threshold of 1.3 [micro]g/m\3\
in the Draft PM<INF>2.5</INF> Precursor Guidance (and below the EPA
recommended threshold of 1.5 [micro]g/m\3\ in the final
PM<INF>2.5</INF> Precursor Guidance), and that for most sites there
would be an increase in ambient PM<INF>2.5</INF> levels in response to
SO<INF>X</INF> reductions (i.e., a disbenefit). The EPA has evaluated
the State's analysis of this disbenefit and resulting conclusion
regarding significance.
Because the results of the sensitivity analysis were all below the
EPA's recommended 24-hour contribution thresholds at both the 30
percent and 70
[[Page 53165]]
percent emissions reductions, and in both the 2013 base year and 2020
(and 2024) future year, it is not necessary to distinguish between the
timing and scale of emissions reductions with respect to the response
of ambient PM<INF>2.5</INF> levels as in the ammonia evaluation where
the results diverged according to scale and timing of modeled emissions
reductions. The EPA's February 2020 Precursor TSD contains additional
detail on the EPA's evaluation of SO<INF>X</INF> as a PM<INF>2.5</INF>
precursor, including the disbenefit associated with a reduction in
SO<INF>X</INF> emissions. Accordingly, we find that the State's
decision to rely on the 2013 sensitivity modeling results for a 30
percent SO<INF>X</INF> reduction is acceptable.
Therefore, on the basis of the modeled ambient PM<INF>2.5</INF>
response to both a 30 percent and 70 percent reduction in
SO<INF>X</INF> emissions in 2013, and on the facts and circumstances of
the area, the EPA proposes to approve the State's demonstration that
SO<INF>X</INF> emissions do not contribute significantly to ambient
PM<INF>2.5</INF> levels that exceed the 1997 24-hour PM<INF>2.5</INF>
NAAQS in the San Joaquin Valley.
c. VOC
For VOC, the State found that the ambient PM<INF>2.5</INF> response
to VOC emissions reductions were generally below the EPA's recommended
contribution threshold of 1.3 [micro]g/m\3\ in the Draft
PM<INF>2.5</INF> Precursor Guidance and below the EPA's recommended
threshold of 1.5 [micro]g/m\3\ in the final PM<INF>2.5</INF> Precursor
Guidance, and often predicted an increase in ambient PM<INF>2.5</INF>
levels in response to such reductions (i.e., a disbenefit), except for
a 70 percent emissions reduction for the 2013 base year, where the
State predicted the ambient PM<INF>2.5</INF> response to be above both
recommended thresholds at a majority of sites. The EPA has evaluated
and agrees with the State's determination that the modeling for future
years is more representative of conditions in the San Joaquin Valley
than the 2013 modeling for sensitivity-based analyses and the State's
resulting conclusion as to whether the contribution from VOC emissions
is significant.
Regarding emissions trends, the EPA agrees that the 8.6 percent
decrease in VOC emissions from 2013 to 2020 and the 9.2 percent
projected decrease from 2013 to 2024 favors reliance on the future year
modeling results. Furthermore, there is a large decrease in
NO<INF>X</INF> emissions over this period, as discussed in the EPA's
evaluation of ammonia, which affects the atmospheric chemistry with
respect to ambient PM<INF>2.5</INF> formation from VOC emissions. The 9
percent VOC emissions reductions and the NO<INF>X</INF> emissions
reductions are projected to result from implementation of existing
baseline measures. We therefore find it reasonable to rely on future
year 2020 or 2024 modeled responses to VOC emissions reductions, and
both years show a disbenefit from VOC emissions reductions. The EPA
also finds that the State provided a reasonable explanation for the VOC
reduction disbenefit and evidence that it occurs in the San Joaquin
Valley.
For these reasons, we propose to approve the State's demonstration
that VOC emissions do not contribute significantly to ambient
PM<INF>2.5</INF> levels that exceed the 1997 24-hour PM<INF>2.5</INF>
NAAQS in the San Joaquin Valley.
C. Attainment Plan Control Strategy
1. Statutory and Regulatory Requirements
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).'' \142\
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\142\ 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.
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Because the 2015 Serious area attainment date has passed, and the
EPA found that the area failed to attain by the Serious area attainment
date, we are evaluating the submission for compliance with the BACM/
BACT requirements now, in conjunction with the State's SIP submission
intended to meet both the Serious area plan and section 189(d) plan
requirements.
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.\143\ 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.\144\ 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 are necessary to attain the
NAAQS in the area.
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\143\ 81 FR 58010, 58081 and General Preamble Addendum, 42011,
42013.
\144\ Id. and General Preamble Addendum, 42009-42010.
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Under the PM<INF>2.5</INF> SIP Requirements Rule, those control
measures that otherwise meet the definition of BACM/BACT but ``can only
be implemented in whole or in part beginning four years after
reclassification'' are referred to as ``additional feasible measures.''
\145\ In accordance with the requirements of CAA section 172(c)(6), a
Serious area plan must include any additional feasible measures to
control emissions of direct PM<INF>2.5</INF> and PM<INF>2.5</INF>
precursors that are necessary and appropriate to provide for attainment
of the relevant NAAQS as expeditiously as practicable and no later than
the applicable attainment date.\146\
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\145\ 40 CFR 51.1000, 40 CFR 51.1010(a)(4)(ii).
\146\ Because the Serious area attainment year has passed and
the area failed to attain by the Serious area attainment date, we
will evaluate the BACM/BACT and additional feasible measure analysis
for the Serious area plan with respect to the current section 189(d)
projected attainment date of December 31, 2020.
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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 and additional feasible measures:
(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.\147\
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\147\ 81 FR 58010, 58083-58085.
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The EPA allows consideration of factors such as physical plant
layout,
[[Page 53166]]
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.\148\
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\148\ 40 CFR 51.1010(a)(3) and 81 FR 58010, 58041-58042.
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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 revisions to meet the basic requirements
of CAA section 110 and any other applicable substantive provisions of
the Act. The EPA is using these steps as guidelines in the evaluation
of the BACM and BACT measures and related analyses in the SJV
PM<INF>2.5</INF> Plan. Furthermore, because the EPA has not previously
taken action to approve the California SIP as meeting the subpart 4
Moderate area planning requirements under CAA section 189 for the 1997
24-hour 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.\149\
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\149\ The EPA does not normally conduct a separate evaluation to
determine whether a Serious area plan's measures also meet the RACM
requirements. As explained in the General Preamble Addendum, we
interpret the BACM requirement as generally subsuming the RACM
requirement--i.e., if we determine that the measures are indeed the
``best available,'' we have necessarily concluded that they are
``reasonably available.'' (General Preamble Addendum, 42010).
Therefore, a separate analysis to determine if the measures
represent a RACM level of control is not necessary. A proposed
approval of a Plan's provisions concerning implementation of BACM is
also a proposed finding that the Plan provides for the
implementation of RACM.
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The overarching requirement for the CAA section 189(d) attainment
control strategy is that it provides for attainment of the NAAQS as
expeditiously as practicable.\150\ The control strategy must include
any additional measures (beyond those already adopted in previous
nonattainment plans 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.\151\ The state
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, based on the
most recent emissions inventory for the area.\152\
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\150\ 81 FR 58010, 58100.
\151\ 40 CFR 50.1010(c)(2)(ii).
\152\ CAA section 189(d) and 40 CFR 51.1010(c).
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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.\153\ 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 emissions reductions beginning from the date by 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 emissions reduction requirement
under section 189(d) for this area is 2017.
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\153\ 81 FR 58010, 58101.
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2. Summary of the State's Submission and the EPA's Evaluation and
Proposed Action
a. Control Strategy
For the Serious area and section 189(d) plan requirements for the
1997 24-hour PM<INF>2.5</INF> NAAQS the State based the control
strategy in the SJV PM<INF>2.5</INF> Plan on ongoing emissions
reductions from baseline control measures.\154\ As we use the term
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 for the 1997 24-hour PM<INF>2.5</INF> NAAQS and beyond. The State
describes the baseline measures in the 2018 PM<INF>2.5</INF> Plan in
Chapter 4,\155\ Appendix C (``Stationary Source Control Measure
Analyses''), and Appendix D (``Mobile Source Control Measure
Analyses''). The State incorporates reductions generated by these
baseline measures into the projected baseline inventories and
reductions resulting from District measures are individually quantified
in Appendix C.
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\154\ Because the 2015 Serious area attainment date has passed,
and the EPA found that the area failed to attain by the Serious area
attainment date, we are evaluating the control strategy for the
Serious area requirements based on the timeline associated with the
current section 189(d) projected attainment date of December 31,
2020.
\155\ 2018 PM<INF>2.5</INF> Plan, Chapter 4, Table 4-2.
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In the 2018 PM<INF>2.5</INF> Plan, CARB indicates that mobile
sources emit over 85 percent of the NO<INF>X</INF> emissions 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.'' \156\
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\156\ 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).
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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 many such mobile source regulations for which it
has issued waiver authorizations as revisions to the California
SIP.\157\
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\157\ For example, see 81 FR 39424 (June 16, 2016); 82 FR 14446
(March 21, 2017); and 83 FR 23232 (May 18, 2018).
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CARB's mobile source program extends beyond regulations that are
subject to the waiver or authorization process set forth in CAA section
209 to 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.\158\
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\158\ 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), revisions to the California on-
road reformulated gasoline and diesel fuel regulations (75 FR 26653,
May 12, 2010), and revisions to the California motor vehicle
inspection and maintenance program (75 FR 38023, July 1, 2010).
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As to stationary and area sources, the SJV PM<INF>2.5</INF> Plan
indicates that regulations adopted for prior attainment plans
[[Page 53167]]
continue to reduce emissions of NO<INF>X</INF> and direct
PM<INF>2.5</INF>.\159\ 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.\160\ The EPA has
approved each of the identified measures into the California SIP,\161\
with two exceptions.
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\159\ 2018 PM<INF>2.5</INF> Plan, Chapter 4, 4-3. For the
District's BACM analysis of stationary and area source measures, see
2018 PM<INF>2.5</INF> Plan, Appendix C.
\160\ 2018 PM<INF>2.5</INF> Plan, Chapter 4, Table 4-1.
\161\ See EPA Region IX's website for information on District
control measures that have been approved into the California SIP,
available at: <a href="https://www.epa.gov/sips-ca/epa-approved-san-joaquin-valley-unified-air-district-regulations-california-sip">https://www.epa.gov/sips-ca/epa-approved-san-joaquin-valley-unified-air-district-regulations-california-sip</a>.
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First, the District amended Rule 4905 (``Natural Gas-fired, Fan-
type, Residential Central Furnaces'') on October 15, 2020, to extend
the period during which manufacturers may pay emissions fees in lieu of
meeting the rule's NO<INF>X</INF> emissions limits.\162\ CARB submitted
the amended rule to the EPA on December 30, 2020,\163\ and the EPA has
not yet proposed any action on this submission. The EPA approved a
prior version of Rule 4905 into the California SIP on March 29,
2016.\164\ As part of that rulemaking, the EPA noted that because of
the option in Rule 4905 to pay mitigation fees in lieu of compliance
with emissions limits, emissions reductions associated with the rule's
emissions limits would not be creditable in any attainment plan without
additional documentation.\165\ Until the District submits the necessary
documentation to credit emissions reductions achieved by Rule 4905
toward an attainment control strategy, this rule is not creditable for
SIP purposes. The Plan indicates that the District attributed 0.06 tpd
of NO<INF>X</INF> reductions between 2013 and 2020 to Rule 4905.\166\
These emissions reductions have de minimis impacts on the attainment
demonstration for the 1997 24-hour PM<INF>2.5</INF> NAAQS in the SJV
PM<INF>2.5</INF> Plan.
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\162\ SJVUAPCD, Final Draft Staff Report with Appendix for
Proposed Amendments to Rule 4905, ``Adopt Proposed Amendments to
Rule 4905 (Natural Gas-fired, Fan-type Central Furnaces),'' 2.
\163\ Letter dated December 28, 2020, from Richard W. Corey,
Executive Officer, CARB, to John Busterud, Regional Administrator,
EPA Region 9. CARB's submittal letter formally withdrew a previously
amended version of Rule 4905 adopted by the District on June 21,
2018 and submitted to the EPA by CARB on November 21, 2018.
\164\ 81 FR 17390 (March 29, 2016) (approving Rule 4905 as
amended January 22, 2015).
\165\ EPA, Region IX Air Division, ``Technical Support Document
for EPA's Proposed Rulemaking for the California State
Implementation Plan (SIP), San Joaquin Valley Unified Air Pollution
Control District's Rule 4905, Natural Gas-Fired, Fan-Type Central
Furnaces,'' October 5, 2015, n. 8.
\166\ 2018 PM<INF>2.5</INF> Plan, Appendix C, C-290.
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Second, the 2018 PM<INF>2.5</INF> Plan lists Rule 4203
(``Particulate Matter Emissions from Incineration of Combustible
Refuse'') as a baseline measure. This rule has not been approved into
the California SIP.\167\ Appendix C of the 2018 PM<INF>2.5</INF> Plan
indicates, however, that the emissions inventory for incineration of
combustible refuse is 0.00 tpd of NO<INF>X</INF> and 0.00 direct
PM<INF>2.5</INF> from 2013 through 2020.\168\ Thus, although the
District included this rule as a baseline measure, there are no
meaningful reductions associated with this rule that would affect the
attainment demonstration in the SJV PM<INF>2.5</INF> Plan.
---------------------------------------------------------------------------
\167\ The EPA does not have any pending SIP submission for Rule
4203.
\168\ 2018 PM<INF>2.5</INF> Plan, Appendix C, C-46.
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In sum, although Table 4-1 of the 2018 PM<INF>2.5</INF> Plan
identifies two baseline measures that are not creditable for SIP
purposes at this time, we find that the total emissions reductions
attributed to these measures in the future baseline inventories have de
minimis effects on the attainment demonstration in the Plan.
b. Best Available Control Measures
We are evaluating the State's BACM demonstration for the 1997 24-
hour PM<INF>2.5</INF> NAAQS against the section 189(b)(1)(B) Serious
area plan BACM requirement, and the section 189(d) plan requirement to
address all Serious area plan requirements that the State has not
already met. Because we have already found that the State failed to
attain the 1997 24-hour PM<INF>2.5</INF> NAAQS in the San Joaquin
Valley area by the Serious area attainment date, and because we have
not previously found that the state has met the BACM requirement for
purposes of the 1997 24-hour PM<INF>2.5</INF> NAAQS, we are evaluating
the State's submission against the Serious area BACM requirement in
light of the section 189(d) control plan timeline. 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.\169\ 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 emissions 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.
---------------------------------------------------------------------------
\169\ Appendices C and D also present an MSM analysis for the
purposes of meeting a precondition for an extension of the Serious
area attainment date under CAA section 188(e) for the 2006
PM<INF>2.5</INF> NAAQS. The San Joaquin Valley area is not subject
to the MSM requirement for the 1997 24-hour PM<INF>2.5</INF> NAAQS.
Thus, the EPA is evaluating the Plan's control strategy for
implementation of BACM and BACT only.
---------------------------------------------------------------------------
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 emissions 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> emissions sources, and control measures implemented in
other ozone and PM<INF>2.5</INF> nonattainment areas in California and
other states.\170\ The District also provides an analysis of several
SIP-approved VOC regulations that, according to the District, also
provide ammonia co-benefits.\171\ Based on these analyses, the District
concludes that all best available control measures for stationary and
area sources are in place in the San Joaquin Valley for NO<INF>X</INF>
and directly emitted PM<INF>2.5</INF> for purposes of meeting the BACM/
BACT requirement for the 1997 24-hour PM<INF>2.5</INF> NAAQS. We
provide an evaluation of many of the District's control measures for
stationary sources and area sources in section III of the EPA's 1997
24-hour PM<INF>2.5</INF> TSD together with recommendations for possible
future improvements to these rules.
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\170\ 2018 PM<INF>2.5</INF> Plan, Chapter 4, section 4.3.1.
\171\ 2018 PM<INF>2.5</INF> Plan, Appendix C., section C.25.
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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 emissions 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
[[Page 53168]]
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.\172\
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\172\ 2018 PM<INF>2.5</INF> Plan, Appendix D, Chapter II.
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Mobile source categories for which CARB has primary responsibility
for reducing emissions in California include most new and existing on-
and non-road engines and vehicles and motor vehicle fuels. The SJV
PM<INF>2.5</INF> Plan's BACM demonstration provides a general
description of CARB's key mobile source programs and regulations and a
comprehensive table listing on-road and non-road mobile source
regulatory actions taken by CARB since 1985.\173\
---------------------------------------------------------------------------
\173\ Id. at Table 17.
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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.\174\ TCMs are projects that
reduce air pollutants from transportation sources by reducing vehicle
use, traffic congestion, or vehicle miles traveled. TCMs are currently
being implemented in the San Joaquin Valley as part of the Congestion
Mitigation and Air Quality cost effectiveness policy adopted by the
eight local jurisdiction MPOs and in the development of each Regional
Transportation Plan (RTP). The Congestion Mitigation and Air Quality
policy, which is included in a number of the District's prior
attainment plan submissions for the ozone and PM<INF>2.5</INF> NAAQS,
provides a standardized process for distributing 20 percent of the
Congestion Mitigation and Air Quality funds to projects that meet a
minimum cost effectiveness threshold beginning in fiscal year 2011. The
MPOs revisited the minimum cost effectiveness standard during the
development of their 2018 RTPs and 2019 Federal Transportation
Improvement Program and concluded that they were implementing all
reasonable transportation control measures.\175\ Appendix D of the
District's ``2016 Ozone Plan for 2008 8-Hour Ozone Standard,'' adopted
June 16, 2016, contains a listing of adopted TCMs for the San Joaquin
Valley.\176\
---------------------------------------------------------------------------
\174\ Id. at D-127 and D-128.
\175\ Id. at D-127.
\176\ Id. and SJVUAPCD, ``2016 Ozone Plan for 2008 8-Hour Ozone
Standard'' (adopted June 16, 2016), Appendix D, Attachment D, tables
D-10 to D-17.
---------------------------------------------------------------------------
We have reviewed the State's and District's analysis and
determination in the SJV PM<INF>2.5</INF> Plan that their baseline
mobile, stationary, and area source control measures meet the
requirements for BACM for sources of direct PM<INF>2.5</INF> and
applicable PM<INF>2.5</INF> plan precursors (i.e., NO<INF>X</INF>) for
purposes of the 1997 24-hour PM<INF>2.5</INF> NAAQS. In our review, we
considered our evaluation of the State's and District's rules in
connection with our approval of the demonstrations for BACM (including
BACT) and MSM for the 2006 PM<INF>2.5</INF> NAAQS.\177\ We find that
the evaluation processes followed by CARB and the District in the SJV
PM<INF>2.5</INF> Plan to identify potential BACM were generally
consistent with the requirements of the PM<INF>2.5</INF> SIP
Requirements Rule, the State's and District's evaluation of potential
measures is appropriate, and the State and District have provided
reasoned justifications for their rejection of potential measures based
on technological or economic infeasibility. We also agree with the
District's conclusion that all reasonable TCMs are being implemented in
the San Joaquin Valley and propose to find that these TCMs implement
BACM for transportation sources.
---------------------------------------------------------------------------
\177\ 85 FR 44192.
---------------------------------------------------------------------------
For the foregoing reasons, we propose to find that the SJV
PM<INF>2.5</INF> Plan provides for the implementation of BACM for
sources of direct PM<INF>2.5</INF> and NO<INF>X</INF> as expeditiously
as practicable in accordance with the requirements of CAA section
189(b)(1)(B), and in satisfaction of both the Serious area and section
189(d) plan requirements.
c. Section 189(d) Five Percent 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 emissions 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 a
reduction of approximately 15.9 tpd of NO<INF>X</INF>, and the targets
for subsequent years are additional reductions of five percent per 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 Emissions 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 ..........................
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 EPA proposes to find that the State's use of 2017 as the
starting point from which the five percent per year emissions
reductions should begin is reasonable and consistent with the CAA. As
discussed in section IV.C.1 of this document, the EPA interprets the
language under CAA section 189(d) to require a state to submit a new
attainment plan to achieve annual reductions ``from the date of such
submission until attainment.'' The 2018 PM<INF>2.5</INF> Plan was not
submitted until May 10, 2019. However, the Serious area attainment
deadline for the San Joaquin Valley nonattainment area for the 1997
PM<INF>2.5</INF> NAAQS was December 31, 2015.\178\ Accordingly, a plan
submittal
[[Page 53169]]
to meet the requirements under section 189(d) was due by December 31,
2016, and reductions were required to occur as of that date. The
decline in emissions from 2017 to 2020 shows that reductions did, in
fact, occur within the required timeframe. Furthermore, the State's
demonstration shows that NO<INF>X</INF> emissions reductions from 2017
to 2020 are greater than the required five percent per year. Thus, the
EPA proposes to find that the SJV PM<INF>2.5</INF> Plan meets the CAA
189(d) requirement to provide for an annual reduction in
PM<INF>2.5</INF> or PM<INF>2.5</INF> precursor emissions of not less
than five percent of the amount of such emissions reported in the most
recent inventory prepared for the area.
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\178\ 80 FR 18528.
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D. Attainment Demonstration and Modeling
1. Statutory and Regulatory Requirements
Section 189(b)(1)(A) of the CAA requires that each Serious area
plan include a demonstration (including air quality modeling) that the
plan provides for attainment of the PM<INF>2.5</INF> NAAQS by the
applicable attainment date. As discussed in section IV of this
proposal, given that the outermost statutory Serious area attainment
date for the San Joaquin Valley area (i.e., December 31, 2015) has
passed and that the EPA has already found that the SJV area failed to
attain by that date, the EPA must evaluate the State's plan for
attainment by a later attainment date. Given that the finding of
failure to attain triggered the State's obligation to submit a new plan
meeting the requirements of section 189(d), the EPA is evaluating the
SJV PM<INF>2.5</INF> Plan in light of the outermost attainment date
required in section 189(d). That section requires that the attainment
date be as expeditious as practicable, but not later than five years
following the EPA's finding that the area failed to attain the NAAQS by
the applicable Serious area attainment date. In this case, the State
projected such attainment by December 31, 2020, i.e., by the relevant
statutory date.
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.\179\ 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.
---------------------------------------------------------------------------
\179\ 40 CFR 51.1011(b)(1); 81 FR 58010, 58102.
---------------------------------------------------------------------------
The EPA's PM<INF>2.5</INF> modeling guidance \180\ (``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
future year.\181\ The modeled response to the emissions changes between
those years is used to calculate relative response factors (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 should 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.\182\
---------------------------------------------------------------------------
\180\ 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, Office of Air Quality Planning and Standards, 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'').
\181\ 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.
\182\ Modeling Guidance, section 4.5, ``What is the Recommended
Modeled Attainment Test for the 24-Hour 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 24-hour 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.\183\
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
emissions 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.
---------------------------------------------------------------------------
\183\ NASA, ``Deriving Information on Surface conditions from
COlumn and VERtically Resolved Observations Relevant to Air
Quality,'' available at <a href="https://www.nasa.gov/mission_pages/discover-aq/index.html">https://www.nasa.gov/mission_pages/discover-aq/index.html</a>.
---------------------------------------------------------------------------
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
[[Page 53170]]
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. CARB's supplemental weight of evidence
analysis further supports the Plan's demonstration of attainment by the
end of 2020. 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 70 percent decrease between 1999 and 2017 in the
number of days above the 1997 24-hour PM<INF>2.5</INF> NAAQS.\184\ 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.\185\ 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.\186\ These trends show that there has been an improvement in air
quality due to emissions reductions in the San Joaquin Valley, although
that point is not fully reflected in the 98th percentile statistic,
which is the basis for the regulatory design value.
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\184\ Weight of Evidence Analysis, 27-28, Figure 14, and Figure
24.
\185\ Id. at Figure 16 and Figure 17.
\186\ Id. at Figure 21.
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The State conducted three CMAQ \187\ 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.\188\
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\187\ CMAQ Version 5.0.2.
\188\ 2018 PM<INF>2.5</INF> Plan, 5-5.
---------------------------------------------------------------------------
Table 4 shows the 2013 base year and 2020 projected future year 24-
hour PM<INF>2.5</INF> design values at monitoring sites in the San
Joaquin Valley. As recommended by the EPA's guidance, the 2013 base
year design value for modeling purposes is a weighted average of three
monitored design values, to minimize the influence of year-to-year
variability. The highest 2020 projected design value is 47.6 [micro]g/
m\3\ at the Bakersfield-California monitoring site, which is below the
65 [micro]g/m\3\ level of the 1997 24-hour PM<INF>2.5</INF> NAAQS.
Table 4--Projected Future 24-Hour PM2.5 Design Values at Monitoring
Sites in the San Joaquin Valley ([micro]g/m \3\)
------------------------------------------------------------------------
2013 Base 2020 Projected
Monitoring site design value design value
------------------------------------------------------------------------
Bakersfield--California................. 64.1 47.6
Fresno-Garland.......................... 60.0 44.3
Hanford................................. 60.0 43.7
Fresno-Hamilton & Winery................ 59.3 45.6
Clovis.................................. 55.8 41.1
Visalia................................. 55.5 42.8
Bakersfield-Planz....................... 55.5 41.2
Madera.................................. 51.0 38.9
Turlock................................. 50.7 37.8
Modesto................................. 47.9 35.8
Merced-M. Street........................ 46.9 32.9
Stockton................................ 42.0 33.5
Merced-S Coffee......................... 41.1 30.0
Manteca................................. 36.9 30.1
Tranquility............................. 29.5 21.5
------------------------------------------------------------------------
Source: 2018 PM2.5 Plan, Table 5-5.
3. The EPA's Review of the State's Submission
The EPA must make several findings in order to approve the modeled
attainment demonstration in an attainment plan SIP submission. First,
we must find that the attainment demonstration's technical bases,
including the emissions inventories and air quality modeling, are
adequate. As discussed in section IV.A of this preamble, we are
proposing to approve the emissions inventories on which the SJV
PM<INF>2.5</INF> Plan's attainment demonstration and related provisions
are based. Furthermore, the EPA has evaluated the State's choice of
model and the extensive discussion in the Modeling Protocol about
modeling procedures, tests, and performance analyses. We find that the
analyses are consistent with the EPA's guidance on modeling for
PM<INF>2.5</INF> attainment planning purposes. Based on these reviews,
we find that the modeling in the Plan is adequate for the purposes of
supporting the RFP demonstration and demonstration of attainment by
2020 and are proposing to approve the air quality modeling. For further
detail, see the EPA's February 2020 Modeling TSD.
Second, we must find that the SIP submittal provides for
expeditious attainment through the timely implementation of the control
strategy. As discussed in section IV.C of this preamble, we are
proposing to approve the control strategy in the SJV PM<INF>2.5</INF>
Plan, including the BACM/BACT demonstration and the five percent
emissions reduction requirement under CAA sections 189(b)(1)(B) and
189(d), respectively.
[[Page 53171]]
Third, the EPA must find that the emissions reductions that are
relied on for attainment in the SIP submission are creditable. As
discussed in section IV.C.2.a, the SJV PM<INF>2.5</INF> Plan relies
principally on rules that have already been adopted and approved by the
EPA to achieve the emissions reductions needed to attain the 1997 24-
hour PM<INF>2.5</INF> NAAQS in the San Joaquin Valley. We present our
evaluation of the rules in section IV.C.2.a and in sections II and III
of the EPA's 1997 24-hour PM<INF>2.5</INF> TSD. We find that all but
two of these rules are SIP-creditable and that the total emissions
reductions attributed to the two measures that are not SIP-creditable
have de minimis impacts on the attainment demonstration in the Plan.
The EPA has also reviewed ambient monitoring data recorded at air
quality monitors throughout the San Joaquin Valley PM<INF>2.5</INF>
nonattainment area during the three years leading up to the projected
December 31, 2020 attainment date (i.e., 2018-2020). As discussed in
section V of this proposal, based on these data, we are proposing to
find that the San Joaquin Valley area attained the 1997 24-hour
PM<INF>2.5</INF> NAAQS by the December 31, 2020 attainment date.
Based on these evaluations, we propose to determine that the SJV
PM<INF>2.5</INF> Plan provides for attainment of the 1997 24-hour
PM<INF>2.5</INF> NAAQS by the most expeditious date practicable,
consistent with the requirements of CAA section 189(d). Furthermore,
because the 2015 Serious area attainment date has passed, and the EPA
found that the area failed to attain by the Serious area attainment
date, we are evaluating the State's compliance with the Serious area
plan requirements in light of the attainment date required under CAA
section 189(d).\189\ Thus, we are also proposing to determine that the
Plan meets the Serious area attainment plan requirement under CAA
section 189(b)(1)(A).
---------------------------------------------------------------------------
\189\ See CAA section 179(d); 40 CFR 51.1004(a)(3).
---------------------------------------------------------------------------
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 emissions 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 emissions reductions sufficient to maintain generally
linear progress toward attainment by the applicable deadline.\190\
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\190\ General Preamble Addendum, 42015.
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Attainment plans for PM<INF>2.5</INF> nonattainment areas should
include detailed schedules for compliance with emissions regulations in
the area and provide corresponding annual emissions reductions to be
achieved by each milestone in the schedule.\191\ In reviewing an
attainment plan under subpart 4, the EPA considers whether the annual
incremental emissions 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.\192\
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\191\ Id. at 42016.
\192\ Id.
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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.\193\ Additionally, states should estimate the RFP
projected emissions for each quantitative milestone year by sector on a
pollutant-by-pollutant basis.\194\
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\193\ 40 CFR 51.1012(a).
\194\ 81 FR 58010, 58056.
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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 emissions 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 emissions controls in the
attainment plan and the requirement to quantify those required
emissions 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 emissions
reductions to date.\195\
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\195\ General Preamble Addendum, 42016-42017.
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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.\196\ 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.\197\
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\196\ General Preamble, 13539, and General Preamble Addendum,
42016.
\197\ 79 FR 31566 (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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[[Page 53172]]
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.\198\ 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.\199\ 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.\200\
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\198\ 40 CFR 51.1013(a)(4).
\199\ 81 FR 58010, 58064.
\200\ Id. at 58064 and 58092.
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Because the EPA designated the San Joaquin Valley area as
nonattainment for the 1997 24-hour PM<INF>2.5</INF> NAAQS effective
April 5, 2005,\201\ 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.\202\ For a Serious area attainment plan
with a statutory attainment date of December 31, 2015, the relevant
quantitative milestone year is December 31, 2017. However, as discussed
in section III, the area did not attain by the statutory Serious area
attainment date and evaluating reasonable further progress toward that
date does not make sense. We are therefore evaluating the Serious area
obligations based on the attainment date the State must meet in a plan
required under CAA section 189(d).\203\ To meet CAA section 189(d), the
SJV PM<INF>2.5</INF> Plan includes a demonstration that the area will
attain by December 31, 2020. Therefore, in accordance with 40 CFR
51.1013(a)(4), the
[…truncated; see source link]Indexed from Federal Register on September 24, 2021.
This is legal information, not legal advice. Laws vary by jurisdiction and change frequently. Always verify current law with official sources and consult a licensed attorney in your jurisdiction for advice on your specific situation.