Document ID: EPA-R09-OAR-2019-0145-0001
Agency: epa
Document Type: Proposed Rule
Title: Air Quality State Implementation Plans; Approvals and Promulgations: California; South Coast Moderate Area Plan and Reclassification as Serious Nonattainment for the 2012 Fine Particulate Matter National Ambient Air Quality Standards
Posted Date: 2020-07-02T04:00Z

[Federal Register Volume 85, Number 128 (Thursday, July 2, 2020)]
[Proposed Rules]
[Pages 40026-40057]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2020-12690]

[[Page 40025]]

Vol. 85

Thursday,

No. 128

July 2, 2020

Part III

 Environmental Protection Agency

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40 CFR Parts 52 and 81

Approval and Promulgation of Implementation Plans; Designation of Areas 
for Air Quality Planning Purposes; California; South Coast Moderate 
Area Plan and Reclassification as Serious Nonattainment for the 2012 
PM2.5 NAAQS; Proposed Rule

  Federal Register / Vol. 85, No. 128 / Thursday, July 2, 2020 / 
Proposed Rules  

[[Page 40026]]

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Parts 52 and 81

[EPA-R09-OAR-2019-0145; FRL-10010-50-Region 9]

Approval and Promulgation of Implementation Plans; Designation of 
Areas for Air Quality Planning Purposes; California; South Coast 
Moderate Area Plan and Reclassification as Serious Nonattainment for 
the 2012 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 or conditionally approve portions of a state implementation 
plan (SIP) revision submitted by California to address Clean Air Act 
(CAA or ``Act'') requirements for the 2006 and 2012 fine particulate 
matter (PM2.5) national ambient air quality standards (NAAQS 
or ``standards'') in the Los Angeles-South Coast Air Basin (``South 
Coast'') PM2.5 nonattainment area. Specifically, the EPA is 
proposing to approve all but the contingency measure element of the 
submitted SIP revision as meeting all applicable Moderate area 
requirements for the 2012 annual PM2.5 NAAQS, and to 
conditionally approve the contingency measure element as meeting both 
the Moderate area contingency measure requirement for the 2012 annual 
PM2.5 NAAQS and the Serious area contingency measure 
requirement for the 2006 24-hour PM2.5 NAAQS. In addition, 
the EPA is proposing to approve 2019 and 2022 motor vehicle emissions 
budgets for use in transportation conformity analyses for the 2012 
annual PM2.5 NAAQS. The EPA is also proposing to reclassify 
the South Coast PM2.5 nonattainment area, including 
reservation areas of Indian country and any other area of Indian 
country within it where the EPA or a tribe has demonstrated that the 
tribe has jurisdiction, as a Serious nonattainment area for the 2012 
annual PM2.5 NAAQS based on the EPA's determination that the 
area cannot practicably attain the standard by the applicable Moderate 
area attainment date of December 31, 2021. Upon final reclassification 
of the South Coast as a Serious area for this NAAQS, California will be 
required to submit a Serious area plan for the area that includes a 
demonstration of attainment by the applicable Serious area attainment 
date, which is no later than December 31, 2025, or by the most 
expeditious alternative date practicable, in accordance with the 
requirements of part D of title I of the CAA.

DATES: Any comments on this proposal must be received by August 3, 
2020.

ADDRESSES: Submit your comments, identified by Docket ID No. EPA-R09-
OAR-2019-0145 at https://www.regulations.gov, or via email to 
graham.ashleyr@epa.gov. For comments submitted at Regulations.gov, 
follow the online instructions for submitting comments. Once submitted, 
comments cannot be edited or removed from Regulations.gov. For either 
manner of submission, the EPA may publish any comment received to its 
public docket. Do not submit electronically any information you 
consider to be Confidential Business Information (CBI) or other 
information whose disclosure is restricted by statute. Multimedia 
submissions (e.g., audio or video) must be accompanied by a written 
comment. The written comment is considered the official comment and 
should include discussion of all points you wish to make. The EPA will 
generally not consider comments or comment contents located outside of 
the primary submission (i.e., on the web, cloud, or other file sharing 
system). For additional submission methods, please contact the person 
identified in the FOR FURTHER INFORMATION CONTACT section. For the full 
EPA public comment policy, information about CBI or multimedia 
submissions, and general guidance on making effective comments, please 
visit https://www.epa.gov/dockets/commenting-epa-dockets.

FOR FURTHER INFORMATION CONTACT: Ashley Graham, Air Planning Office 
(AIR-2), EPA Region IX, (415) 972-3877, graham.ashleyr@epa.gov.

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

Table of Contents

I. Background for Proposed Action
II. Summary of the South Coast PM2.5 Plan
III. Clean Air Act Requirements for Moderate PM2.5 
Nonattainment Area Plans
IV. Completeness Review of the South Coast PM2.5 Plan
V. Review of the South Coast PM2.5 Plan
    A. Emissions Inventory
    B. PM2.5 Precursors
    C. Air Quality Modeling
    D. Reasonably Available Control Measures and Control Strategy
    E. Major Stationary Source Control Requirements Under CAA 
Section 189(e)
    F. Demonstration That Attainment by the Moderate Area Attainment 
Date Is Impracticable
    G. Reasonable Further Progress and Quantitative Milestones
    H. Contingency Measures
    I. Motor Vehicle Emissions Budgets
VI. Reclassification as Serious Nonattainment and Serious Area SIP 
Requirements
    A. Reclassification as Serious and Applicable Attainment Date
    B. Clean Air Act Requirements for Serious PM2.5 
Nonattainment Area Plans
    C. Statutory Deadline for Submittal of the Serious Area Plan
VII. Reclassification of Areas of Indian Country
VIII. Summary of Proposed Actions and Request for Public Comment
IX. Statutory and Executive Order Reviews

I. Background for Proposed Action

    On October 17, 2006, the EPA strengthened the 24-hour (daily) NAAQS 
for particulate matter with a diameter of 2.5 microns or less 
(PM2.5) by lowering the level from 65 micrograms ([micro]g) 
per cubic meter (m\3\) to 35 [micro]g/m\3\ (``2006 PM2.5 
NAAQS'').\1\ On January 15, 2013, the EPA strengthened the primary 
annual NAAQS for PM2.5 by lowering the level from 15.0 
[micro]g/m\3\ to 12.0 [micro]g/m\3\ (``2012 PM2.5 
NAAQS'').\2\ The EPA established these standards after considering 
substantial evidence from numerous health studies demonstrating that 
serious health effects are associated with exposures to 
PM2.5 concentrations above these levels.
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    \1\ 71 FR 61144 and 40 CFR 50.13. The EPA first established 
NAAQS for PM2.5 on July 18, 1997 (62 FR 38652), including 
annual standards of 15.0 [micro]g/m\3\ based on a 3-year average of 
annual mean concentrations and 24-hour (daily) standards of 65 
[micro]g/m\3\ based on a 3-year average of 98th percentile 24-hour 
concentrations (40 CFR 50.7).
    \2\ 78 FR 3086 and 40 CFR 50.18. Unless otherwise noted, all 
references to the PM2.5 standards in this notice are to 
the 2012 annual NAAQS of 12.0 [micro]g/m\3\ codified at 40 CFR 
50.18.
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    Epidemiological studies have shown statistically significant 
correlations between elevated PM2.5 levels and premature 
mortality. Other important health effects associated with 
PM2.5 exposure include aggravation of respiratory and 
cardiovascular disease (as indicated by increased hospital admissions, 
emergency room visits, absences from school or work, and restricted 
activity days), changes in lung function, and increased respiratory 
symptoms. Individuals particularly sensitive to PM2.5 
exposure include older adults, people with heart and lung disease, and 
children.\3\ PM2.5 can be emitted directly into the 
atmosphere as a solid or liquid particle (``primary PM2.5'' 
or ``direct PM2.5'') or can be formed in the atmosphere 
(``secondary PM2.5'') as a result of various chemical 
reactions among precursor pollutants such as nitrogen oxides 
(NOX), sulfur oxides (SOX), volatile organic

[[Page 40027]]

compounds (VOC), and ammonia (NH3).\4\
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    \3\ Id.
    \4\ 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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    Following promulgation of a new or revised NAAQS, the EPA is 
required by CAA section 107(d) to designate areas throughout the nation 
as attaining or not attaining the NAAQS. On November 13, 2009, the EPA 
designated the South Coast area as nonattainment for the 2006 
PM2.5 NAAQS.\5\ The EPA classified the area as Moderate 
nonattainment on June 2, 2014 and reclassified it as Serious 
nonattainment for these NAAQS on January 13, 2016.\6\ On January 15, 
2015, the EPA designated and classified the South Coast area as 
Moderate nonattainment for the 2012 PM2.5 NAAQS.\7\ The 
South Coast area is also designated and classified as Moderate 
nonattainment for the 1997 annual and 24-hour PM2.5 
NAAQS.\8\
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    \5\ 74 FR 58688 (codified at 40 CFR 81.305).
    \6\ 79 FR 31566 and 81 FR 1514. The EPA promulgated these 
PM2.5 nonattainment area classifications in response to a 
2013 decision of the Court of Appeals for the D.C. Circuit remanding 
the EPA's prior implementation rule for the PM2.5 NAAQS 
and directing the EPA to promulgate implementation rules pursuant to 
subpart 4 of part D, title I of the Act. Natural Resources Defense 
Council v. EPA, 706 F.3d 428 (D.C. Cir. 2013).
    \7\ 80 FR 2206 (codified at 40 CFR 81.305).
    \8\ 70 FR 944 (January 5, 2005) (codified at 40 CFR 81.305). In 
November 2007, California submitted the 2007 PM2.5 Plan 
to provide for attainment of the 1997 PM2.5 standards in 
the South Coast. On November 9, 2011, the EPA approved all but the 
contingency measures in the 2007 PM2.5 Plan (76 FR 
69928), and on October 29, 2013, the EPA approved a revised 
contingency measure SIP for the area (78 FR 64402). On July 25, 
2016, the EPA determined that the South Coast area had attained the 
1997 annual and 24-hour PM2.5 NAAQS based on 2011-2013 
monitoring data, suspending any remaining attainment-related 
planning requirements for purposes of the 1997 PM2.5 
NAAQS in this area (81 FR 48350).
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    On April 27, 2017, the California Air Resources Board (CARB) 
submitted the ``Final 2016 Air Quality Management Plan (March 2017)'' 
to provide for attainment of both the 2006 PM2.5 NAAQS and 
the 2012 PM2.5 NAAQS in the South Coast (``2016 
PM2.5 Plan'' or ``Plan'').\9\ On February 12, 2019, the EPA 
approved those portions of the 2016 PM2.5 Plan that pertain 
to the requirements for implementing the 2006 PM2.5 NAAQS, 
except for the contingency measure component of the Plan.\10\
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    \9\ Letter dated April 27, 2017, from Richard Corey, Executive 
Officer, CARB, to Alexis Strauss, Acting Regional Administrator, EPA 
Region IX (transmitting ``Final 2016 Air Quality Management Plan 
(March 2017)'').
    \10\ 84 FR 3305. As part of this action, the EPA found that, for 
purposes of the 2006 PM2.5 NAAQS, the requirement for 
contingency measures to be undertaken if the area fails to make RFP 
under CAA section 172(c)(9) was moot as applied to the 2017 
milestone year because CARB and the District had demonstrated to the 
EPA's satisfaction that the 2017 milestones in the plan had been 
met. The EPA took no action with respect to RFP contingency measures 
for the 2020 milestone year or attainment contingency measures for 
these NAAQS.
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    The South Coast PM2.5 nonattainment area is home to 
about 17 million people, has a diverse economic base, and contains one 
of the highest-volume port areas in the world. For a description of the 
geographic boundaries of the South Coast PM2.5 nonattainment 
area, see 40 CFR 81.305. The local air district with primary 
responsibility for developing a plan to attain the PM2.5 
NAAQS in the South Coast area is the South Coast Air Quality Management 
District (SCAQMD or ``District''). The District works cooperatively 
with CARB in preparing these plans. Authority for regulating sources in 
the South Coast is split between the District, which has responsibility 
for regulating stationary and most area sources, and CARB, which has 
responsibility for regulating most mobile sources and some categories 
of consumer products.

II. Summary of the South Coast PM2.5 Plan

    We are proposing action on portions of a California SIP submission 
that address the Moderate area plan requirements for the 2012 annual 
PM2.5 NAAQS and the Serious area contingency measure 
requirement for the 2006 24-hour PM2.5 NAAQS in the South 
Coast PM2.5 nonattainment area. The SCAQMD Governing Board 
adopted the ``Final 2016 Air Quality Management Plan (March 2017)'' on 
March 3, 2017, and CARB submitted this SIP revision to the EPA on April 
27, 2017.\11\ We refer to this SIP submission herein as the ``2016 
PM2.5 Plan'' or ``Plan.''
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    \11\ Letter dated April 27, 2017, from Richard Corey, Executive 
Officer, CARB, to Alexis Strauss, Acting Regional Administrator, EPA 
Region IX, with enclosures.
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    The 2016 PM2.5 Plan is organized into eleven chapters, 
each addressing a specific topic. We summarize below each of the 
chapters relevant to the 2012 PM2.5 NAAQS and the 
contingency measure requirement for the 2006 PM2.5 
NAAQS.\12\ Chapter 1, ``Introduction,'' provides general background, 
including a discussion of the purpose of the Plan, historical air 
quality progress in the South Coast, and the District's approach to air 
quality planning. Chapter 2, ``Air Quality and Health Effects,'' 
discusses current air quality in comparison with federal health-based 
air pollution standards. Chapter 3, ``Base Year and Future Year 
Emissions,'' summarizes emissions inventories, estimates current 
emissions by source and pollutant, and projects future emissions with 
and without growth. Chapter 4, ``Control Strategy and Implementation,'' 
presents the control strategy, specific measures, and implementation 
schedules to attain the air quality standards by the specified 
attainment dates. Chapter 5, ``Future Air Quality,'' describes the 
modeling approach used in the Plan and summarizes the South Coast's 
future air quality projections with and without the control strategy. 
Chapter 6, ``Federal and State Clean Air Act Requirements,'' discusses 
specific federal and state requirements as they pertain to the South 
Coast, including anti-backsliding requirements for revoked standards. 
Chapter 11, ``Public Process and Participation,'' describes the 
District's public outreach effort associated with the development of 
the Plan. Finally, a glossary is provided at the end of the document, 
presenting definitions of terms commonly used in the Plan.
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    \12\ The following chapters in the Plan are not relevant to the 
2006 or 2012 PM2.5 NAAQS and were not reviewed as part of 
this action: Chapter 7, ``Current and Future Air Quality--Desert 
Nonattainment Areas,'' describes the air quality status of the 
Coachella Valley, including emissions inventories, designations, and 
current and future air quality. Chapter 8, ``Looking Beyond Current 
Requirements,'' assesses the South Coast air basin's status with 
respect to the 2015 8-hour ozone standard of 70 ppb. Chapter 9, 
``Air Toxic Control Strategy,'' examines the ongoing efforts to 
reduce health risk from toxic air contaminants, co-benefits from 
reducing criteria pollutants, and potential future actions; and 
Chapter 10, ``Climate and Energy,'' provides a description of 
current and projected energy demand and supply issues in the South 
Coast air basin, and the relationship between air quality 
improvement and greenhouse gas mitigation goals.
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    The Plan also includes the following technical appendices:
     Appendix I (``Health Effects'') presents a summary of 
scientific findings on the health effects of ambient air pollution.
     Appendix II (``Current Air Quality'') contains a detailed 
summary of the air quality in 2014, along with prior year trends, in 
both the South Coast and the Coachella Valley.
     Appendix III (``Base and Future Year Emission Inventory'') 
presents the 2012 base year emissions inventory and projected emissions 
inventories of air pollutants in future attainment years for both 
annual average and summer planning inventories.
     Appendix IV-A (``SCAQMD's Stationary and Mobile Source 
Control Measures'') describes SCAQMD's proposed stationary and mobile 
source control measures to attain the federal ozone and 
PM2.5 standards.
     Appendix IV-B (``CARB's Mobile Source Strategy'') 
describes CARB's proposed 2016 strategy to attain health-based federal 
air quality standards.

[[Page 40028]]

     Appendix IV-C (``Regional Transportation Strategy and 
Control Measures'') describes the Southern California Association of 
Governments' (SCAG) ``Final 2016-2040 Regional Transportation Plan/
Sustainable Communities Strategy'' and transportation control measures 
included in the 2016 PM2.5 Plan.
     Appendix V (``Modeling and Attainment Demonstrations'') 
provides the details of the regional modeling for the attainment 
demonstration.
     Appendix VI (``Compliance with Other Clean Air Act 
Requirements'') provides the District's demonstration that the Plan 
complies with specific federal and California Clean Air Act 
requirements.
    CARB adopted additional documents on March 23, 2017 that supplement 
the analyses and demonstrations adopted by the SCAQMD on March 3, 2017. 
In particular, the ``CARB Staff Report, ARB Review of 2016 AQMP for the 
South Coast Air Basin and Coachella Valley'' (``CARB Staff Report'') 
includes in Appendix D a weight of evidence analysis for the SCAQMD's 
attainment demonstration for the 24-hour and annual PM2.5 
NAAQS. Also, to supplement the contingency measure element of the 2016 
PM2.5 Plan, CARB submitted a letter dated January 29, 2019 
containing the District's commitment to adopt a control measure by a 
date certain for purposes of satisfying CAA contingency measure 
requirements for the 2006 and 2012 PM2.5 NAAQS.\13\ The 
District later clarified its January 29, 2019 commitment in a letter 
dated February 12, 2020, and CARB submitted the District's clarified 
commitment together with related State commitments to the EPA by letter 
dated March 3, 2020.\14\ We discuss these commitments as part of our 
evaluation of the contingency measure element of the 2016 
PM2.5 Plan, in section V.H.
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    \13\ Letter dated February 13, 2019, from Michael Benjamin, Air 
Quality Planning and Science Division, CARB, to Mike Stoker, 
Regional Administrator, EPA Region IX (transmitting letter dated 
January 29, 2019, from Wayne Nastri, Executive Officer, SCAQMD, to 
Richard Corey, Executive Officer, CARB). In its January 29, 2019 
letter, the District committed to modify an existing rule or adopt a 
new rule to create a contingency measure that would be triggered if 
the area fails to meet an RFP requirement, to submit a quantitative 
milestone report, to meet a quantitative milestone, or to attain the 
2006 24-hour or 2012 annual PM2.5 NAAQS.
    \14\ Letter dated March 3, 2020, from Michael Benjamin, Air 
Quality Planning and Science Division, CARB, to Mike Stoker, 
Regional Administrator, EPA Region IX (transmitting letter dated 
February 12, 2020, from Wayne Nastri, Executive Officer, SCAQMD, to 
Richard Corey, Executive Officer, CARB). In its February 12, 2020 
letter, the District specifically committed to modify Rule 445 
(``Wood Burning Devices'') to lower the mandatory wood burning 
curtailment threshold in the rule following any of the EPA findings 
listed in 40 CFR 51.1014(a). In its March 3, 2020 letter, CARB 
committed to submit the revised District rule to the EPA as a SIP 
revision by a date certain.
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    We present our evaluation of the 2016 PM2.5 Plan in 
Section V of this proposed rule.

III. Clean Air Act Requirements for Moderate PM2.5 Nonattainment Area 
Plans

    With respect to the statutory requirements for particulate matter 
(PM) attainment plans, the general nonattainment area planning 
requirements of title I, part D of the CAA are found in subpart 1, and 
the Moderate area planning requirements specifically for PM are found 
in subpart 4.
    The EPA has a longstanding general guidance document that 
interprets the 1990 amendments to the CAA, commonly referred to as the 
General Preamble for the Implementation of Title I of the Clean Air Act 
Amendments of 1990 (``General Preamble'').\15\ The General Preamble 
addresses the relationship between the subpart 1 and subpart 4 
requirements and provides recommendations to states for meeting certain 
statutory requirements for PM attainment plans. As explained in the 
General Preamble, specific requirements applicable to Moderate area 
attainment plan SIP submissions for the PM NAAQS are set forth in 
subpart 4 of part D, title I of the Act, but such SIP submissions must 
also meet the general attainment planning provisions in subpart 1 of 
part D, title I of the Act, to the extent these provisions ``are not 
otherwise subsumed by, or integrally related to,'' the more specific 
subpart 4 requirements.\16\
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    \15\ General Preamble, 57 FR 13498 (April 16, 1992).
    \16\ Id. at 13538.
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    To implement the PM2.5 NAAQS, the EPA has also 
promulgated the ``Fine Particle Matter National Ambient Air Quality 
Standard: State Implementation Plan Requirements; Final Rule'' 
(hereinafter, the ``PM2.5 SIP Requirements Rule'').\17\ The 
PM2.5 SIP Requirements Rule establishes regulatory 
requirements and provides additional guidance applicable to attainment 
plan submissions for the PM2.5 NAAQS, including the 2006 24-
hour and 2012 annual PM2.5 NAAQS at issue in this action.
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    \17\ 81 FR 58010 (August 24, 2016).
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    The general subpart 1 statutory requirements for attainment plans 
include: (i) The section 172(c)(1) requirement for reasonably available 
control measures (RACM)/reasonably available control technology (RACT) 
and attainment demonstrations; (ii) the section 172(c)(2) requirement 
to demonstrate reasonable further progress (RFP); (iii) the section 
172(c)(3) requirement for emissions inventories; (iv) the section 
172(c)(5) requirement for a nonattainment new source review (NNSR) 
permitting program; and (v) the section 172(c)(9) requirement for 
contingency measures.
    The more specific subpart 4 statutory requirements for Moderate 
PM2.5 nonattainment areas include: (i) The section 
189(a)(1)(A) and 189(e) NNSR permit program requirements; (ii) the 
section 189(a)(1)(B) requirement for attainment demonstrations; (iii) 
the section 189(a)(1)(C) requirement for RACM; and (iv) the section 
189(c) requirements for RFP and quantitative milestones. Under subpart 
4, states with Moderate PM2.5 nonattainment areas must 
provide for attainment in the area as expeditiously as practicable but 
no later than the latest permissible attainment date under CAA section 
188(c), i.e., December 31, 2021 for the 2012 PM2.5 NAAQS in 
the South Coast.\18\ In addition, under subpart 4, direct 
PM2.5 and all precursors to the formation of 
PM2.5 are subject to control unless the EPA approves a 
demonstration from the State establishing that a given precursor does 
not contribute significantly to PM2.5 levels that exceed the 
PM2.5 NAAQS in the area.\19\
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    \18\ Generally, under CAA section 188(c), the latest permissible 
attainment date for a Moderate nonattainment area is the end of the 
sixth calendar year after the area's designation as nonattainment. 
Because the EPA designated and classified the South Coast as a 
Moderate nonattainment area for the 2012 PM2.5 NAAQS 
effective April 15, 2015 (80 FR 2206, 2215), the latest permissible 
attainment date for these NAAQS in the South Coast is December 31, 
2021.
    \19\ 40 CFR 51.1006 and 51.1009.
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IV. Completeness Review of the South Coast PM2.5 Plan

    CAA sections 110(a)(1) and (2) and 110(l) require each state to 
provide reasonable public notice and an opportunity for a public 
hearing prior to the adoption and submittal of a SIP or SIP revision to 
the EPA. To meet this requirement, every SIP submission should include 
evidence that adequate public notice was given and an opportunity for a 
public hearing was provided consistent with the EPA's implementing 
regulations in 40 CFR 51.102.
    Both the District and CARB satisfied applicable statutory and 
regulatory requirements for reasonable public notice and hearing prior 
to adoption and

[[Page 40029]]

submission of the 2016 PM2.5 Plan. The District conducted 
numerous public workshops, provided public comment periods, and held a 
public hearing prior to its adoption of the Plan on March 3, 2017.\20\ 
CARB also provided the required public notice and opportunity for 
public comment prior to its March 23, 2017 public hearing and adoption 
of the Plan.\21\ Each submission includes proof of publication of 
notices for the respective public hearings, and transcripts for the 
public hearings.\22\ We find, therefore, that the 2016 PM2.5 
Plan meets the requirements for reasonable notice and public hearings 
in CAA sections 110(a) and 110(l).
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    \20\ SCAQMD, Notice of Public Hearing, ``Proposed 2016 Air 
Quality Management Plan for the South Coast Air Quality Management 
District and Report on the Health Impacts of Particulate Matter Air 
Pollution in the South Coast Air Basin,'' December 14, 2016.
    \21\ CARB, ``Notice of Public Meeting to Consider Adopting the 
2016 Air Quality Management Plan for Ozone and PM2.5 for 
the South Coast Air Basin and the Coachella Valley,'' March 6, 2017.
    \22\ Memorandum dated March 6, 2017, from Denise Garzaro, Clerk 
of the Board, SCAQMD, to Arlene Martinez, Administrative Secretary, 
Planning, Rule Development, and Area Sources, Subject: ``SIP 
Documentation, January 24, 2017; and California Air Resources Board, 
Notice of Public Meeting to Consider Adopting the 2016 Air Quality 
Management Plan for Ozone and PM2.5 for the South Coast 
Air Basin and the Coachella Valley.''
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    CAA section 110(k)(1)(B) requires the EPA to determine whether a 
SIP submittal 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. The 2016 
PM2.5 Plan, which CARB submitted on April 27, 2017, became 
complete by operation of law on October 27, 2017.

V. Review of the South Coast PM2.5 Plan

A. Emissions Inventory

1. Requirements for Emissions Inventories
    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. We refer to this inventory as the ``base year inventory.'' The 
EPA has established regulatory requirements for base year and other 
emissions inventories in the PM2.5 SIP Requirements Rule 
\23\ and issued guidance concerning emissions inventories for 
PM2.5 nonattainment areas.\24\
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    \23\ 40 CFR 51.1008.
    \24\ 81 FR 58010, 58078-58079 and ``Emissions Inventory Guidance 
for Implementation of Ozone and Particulate Matter National Ambient 
Air Quality Standards (NAAQS) and Regional Haze Regulations,'' EPA, 
May 2017 (``Emissions Inventory Guidance''), available at https://www.epa.gov/air-emissions-inventories/air-emissions-inventory-guidance-implementation-ozone-and-particulate.
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    The base year emissions inventory should provide a state's best 
estimate of actual emissions from all sources of the relevant 
pollutants in the area, i.e., all emissions that contribute to the 
formation of a particular NAAQS pollutant. For the PM2.5 
NAAQS, the base year emissions inventory must include direct 
PM2.5 emissions, separately reported filterable and 
condensable PM2.5 emissions,\25\ and emissions of all 
chemical precursors to the formation of secondary PM2.5: 
NOX, SO2, VOC, and ammonia.\26\ In addition, the 
emissions inventory base year for a Moderate PM2.5 
nonattainment area must be one of the three years for which monitored 
data were used to designate the area as nonattainment, or another 
technically appropriate year justified by the state in its Moderate 
area SIP submission.\27\
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    \25\ 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.
    \26\ 40 CFR 51.1008.
    \27\ 40 CFR 51.1008(a)(1)(i).
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    A state must include in its SIP submission documentation explaining 
how the emissions data were calculated. In estimating mobile source 
emissions, a state should use the latest emissions models and planning 
assumptions available at the time it develops the SIP submission. 
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.28 29 At 
the time the 2016 PM2.5 Plan was developed, California was 
required to use EMFAC2014 to estimate tailpipe and brake and tire wear 
emissions of PM2.5, NOX, SO2, and VOC 
from on-road mobile sources.\30\
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    \28\ 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 
http://www.arb.ca.gov/ei/areasrc/fullpdf/full7-9_2016.pdf.
    \29\ AP-42 has been published since 1972 as the primary source 
of the EPA's emission factor information. 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.
    \30\ The EMFAC model (short for EMission FACtor) is a computer 
model developed by CARB. The EPA approved and announced the 
availability of EMFAC2014 for use in SIP development and 
transportation conformity in California on December 14, 2015 (80 FR 
77337). The EPA's approval of the EMFAC2014 emissions model for SIP 
and conformity purposes was effective on the date of publication in 
the Federal Register. On August 15, 2019, the EPA approved and 
announced the availability of EMFAC2017, the latest update to the 
EMFAC model for use by state and local governments to meet CAA 
requirements (84 FR 41717). EMFAC2017 was not available to the State 
and District at the time they were developing the 2016 
PM2.5 Plan.
---------------------------------------------------------------------------

    In addition to the base year inventory submitted to meet the 
requirements of CAA section 172(c)(3), a state must also submit future 
``baseline inventories'' for the projected attainment year, each RFP 
milestone year, and any other year of significance for meeting 
applicable CAA requirements.\31\ By ``baseline inventories'' (referred 
to in the 2016 PM2.5 Plan as ``baseline inventories'' or 
``future baseline inventories''), we mean projected emissions 
inventories for future years that account for, among other things, the 
ongoing effects of economic growth and adopted emission control 
requirements. The SIP submission should include documentation to 
explain how the state calculated the emissions projections.
---------------------------------------------------------------------------

    \31\ 40 CFR 51.1008(a)(2) and 51.1012(a)(2); see also EPA, 
``Emissions Inventory Guidance for Implementation of Ozone and 
Particulate Matter National Ambient Air Quality Standards (NAAQS) 
and Regional Haze Regulations,'' May 2017, available at https://www.epa.gov/sites/production/files/2017-07/documents/ei_guidance_may_2017_final_rev.pdf.
---------------------------------------------------------------------------

2. Emissions Inventories in the 2016 PM2.5 Plan
    The annual average planning inventories for direct PM2.5 
and all PM2.5 precursors (NOX, 
SOX,\32\ VOC, and ammonia) for the South Coast 
PM2.5 nonattainment area, together with documentation for 
the inventories, are found in Chapter 3, Appendix III, and Appendix V 
of the Plan. Appendix V also contains additional inventory 
documentation specific to the air quality modeling inventories. These 
portions of the Plan contain annual average daily inventories of actual 
emissions for the 2012 base year, and projected inventories for the 
future 2019 RFP baseline year, the 2021 Moderate area attainment year, 
and the 2022 post-attainment RFP year.\33\ The annual

[[Page 40030]]

average daily inventory is used to evaluate sources of emissions for 
attainment of the 2012 PM2.5 NAAQS.
---------------------------------------------------------------------------

    \32\ The 2016 PM2.5 Plan generally uses ``sulfur 
oxides'' or ``SOX'' in reference to SO2 as a 
precursor to the formation of PM2.5. We use 
SOX and SO2 interchangeably throughout this 
notice.
    \33\ The 2016 PM2.5 Plan includes summer day 
inventories for ozone planning purposes, and inventories for Serious 
area planning purposes for both the 2006 and 2012 PM2.5 
NAAQS. The 2016 PM2.5 Plan therefore includes annual 
average and summer day inventories for all years between 2017 and 
2031, except 2029. 2016 PM2.5 Plan, Appendix III, 
Attachment A.
---------------------------------------------------------------------------

    Future emissions forecasts are primarily based on demographic and 
economic growth projections provided by SCAG. Baseline inventories 
reflect all District control measures adopted by December 2015 and CARB 
rules adopted by November 2015. Growth factors used to project these 
baseline inventories are derived mainly from data obtained from 
SCAG.\34\
---------------------------------------------------------------------------

    \34\ Id. at III-2-6.
---------------------------------------------------------------------------

    Each emissions inventory is divided into two source 
classifications: Stationary sources (i.e., point sources and area 
sources) and mobile sources (i.e., on-road and non-road sources of 
emissions). Point sources in the South Coast air basin that emit four 
tons per year (tpy) or more of PM, NOX, SOX, or 
VOC report annual emissions to the District. Point source emissions for 
the 2012 base year emissions inventory are generally based on reported 
data from facilities using the District's Annual Emissions Reporting 
program.\35\ Area sources include smaller emission sources distributed 
across the nonattainment area. CARB and the District estimate emissions 
for about 400 area source categories using established inventory 
methods, including publicly available emission factors and activity 
information. Activity data may come from national survey data such as 
from the Energy Information Administration or from local sources such 
as the Southern California Gas Company, paint suppliers, and District 
databases. Emission factors can be based on a number of sources 
including source tests, compliance reports, and the EPA's AP-42.
---------------------------------------------------------------------------

    \35\ Information about the SCAQMD's Annual Emissions Reporting 
program is available at http://www.aqmd.gov/home/rules-compliance/compliance/annual-emission-reporting.
---------------------------------------------------------------------------

    Emissions inventories are constantly being revised and improved. 
Between the finalization of the South Coast 2012 Air Quality Management 
Plan (``2012 AQMP'') and the development of the 2016 PM2.5 
Plan, the District improved and updated its emissions estimation 
methodologies for liquified petroleum gas combustion sources, natural 
gas combustion sources, Regional Clean Air Incentives Market (RECLAIM) 
NOX emissions sources (based on 2015 program amendments), 
livestock waste management operations, gasoline dispensing facilities, 
composting operations, oil and gas production, and architectural 
coatings.
    On-road emissions inventories are calculated using CARB's EMFAC2014 
model and the travel activity data provided by SCAG in ``The 2016-2040 
Regional Transportation Plan/Sustainable Communities Strategy.'' \36\ 
Re-entrained paved road dust emissions are calculated using the EPA's 
AP-42 road dust methodology.\37\
---------------------------------------------------------------------------

    \36\ SCAG's ``The 2016-2040 Regional Transportation Plan/
Sustainable Communities Strategy'' is available at http://scagrtpscs.net/Pages/FINAL2016RTPSCS.aspx.
    \37\ CARB, Miscellaneous Process Methodology 7.9 Entrained Road 
Travel, Paved Road Dust, (Revised and updated, November 2016) 
available at https://www.arb.ca.gov/ei/areasrc/fullpdf/full7-9_2016.pdf.
---------------------------------------------------------------------------

    CARB provided emissions inventories for off-road equipment, 
including construction and mining equipment, industrial and commercial 
equipment, lawn and garden equipment, agricultural equipment, ocean-
going vessels, commercial harbor craft, locomotives, cargo handling 
equipment, pleasure craft, and recreational vehicles. CARB uses several 
models to estimate emissions for more than one hundred off-road 
equipment categories.\38\ Aircraft emissions are developed in 
conjunction with the airports in the region.
---------------------------------------------------------------------------

    \38\ 2016 PM2.5 Plan, III-1-24.
---------------------------------------------------------------------------

    Table 1 provides a summary of the District's 2012 base year annual 
average emissions estimates for direct PM2.5 and all 
PM2.5 precursors. These inventories provide the basis for 
the control measure analysis and the RFP and impracticability 
demonstrations in the 2016 PM2.5 Plan. For a more detailed 
discussion of the inventories, see Appendix III of the Plan.

                                  Table 1--South Coast 2012 Base Year Emissions
                                         [Annual average, tons per day]
----------------------------------------------------------------------------------------------------------------
                                   Direct PM2.5
                                                        NOX             SOX             VOC           Ammonia
----------------------------------------------------------------------------------------------------------------
Stationary Sources..............              44              70              10             212              63
On-Road Mobile Sources..........              14             317               2             158              18
Off-Road Mobile Sources.........               8             153               6             100               0
                                 -------------------------------------------------------------------------------
    Total.......................              66             540              18             470              81
----------------------------------------------------------------------------------------------------------------
Source: 2016 PM2.5 Plan, Table 3-2. Values may not be precise due to rounding.

Condensable Particulate Matter
    The PM2.5 SIP Requirements Rule states that ``[t]he 
inventory shall include direct PM2.5 emissions, separately 
reported PM2.5 filterable and condensable emissions, and 
emissions of the scientific PM2.5 precursors, including 
precursors that are not PM2.5 plan precursors pursuant to a 
precursor demonstration under Sec.  51.1006.'' \39\ On June 15, 2018, 
the SCAQMD submitted a technical supplement to the SIP containing 
emissions estimates for both condensable and filterable 
PM2.5 emissions from specified sources of direct 
PM2.5 in the South Coast area.\40\ The supplement provides 
filterable and condensable emissions estimates, expressed as annual 
average PM2.5 emissions, for all of the identified source 
categories for the 2012 base year, the 2019 RFP year, the 2021 Moderate 
area attainment year, and the 2022 RFP year, as well as subsequent 
years.\41\
---------------------------------------------------------------------------

    \39\ 40 CFR 51.1008(a)(1)(iv).
    \40\ Letter dated June 15, 2018, from Philip Fine, Deputy 
Executive Officer, SCAQMD, to Amy Zimpfer, Associate Director, EPA 
Region IX, Subject: ``Condensable and Filterable Portions of 
PM2.5 emissions in the 2016 AQMP.''
    \41\ Id., Appendix A.
---------------------------------------------------------------------------

    The 2016 PM2.5 Plan relies on several SIP-approved rules 
that regulate direct PM emissions as part of the PM2.5 
control strategy, including Rule 445 (``Wood-Burning Devices''), as 
amended May 3, 2013; Rule 1138 (``Control of Emissions from Restaurant 
Operations''), adopted November 14, 1997; and Rule 1155 (``Particulate 
Matter (PM) Control Devices''), as amended May 2, 2014. As part of our 
action on any rules that regulate direct PM2.5 emissions, we 
evaluate the emission limits in the rule to ensure that they 
appropriately address condensable PM, as required by 40 CFR 
51.1008(a)(1)(iv). We note that the SIP-

[[Page 40031]]

approved version of Rule 1138 requires testing according to the 
District's protocol, which requires measurement of both condensable and 
filterable PM in accordance with SCAQMD Test Method 5.1.\42\ We also 
note that the SIP-approved version of Rule 1155 requires measurement of 
both condensable and filterable PM in accordance with SCAQMD Test 
Methods 5.1, 5.2, or 5.3 as applicable.43 44
---------------------------------------------------------------------------

    \42\ Rule 1138 (adopted November 14, 1997), paragraph (c)(1) and 
(g), SCAQMD Protocol paragraph 3.1, and SCAQMD Protocol, 
``Determination of Particulate and Volatile Organic Compound 
Emissions from Restaurant Operations,'' November 14, 1997 (available 
at https://www.regulations.gov/contentStreamer?documentId=EPA-R09-OAR-2017-0490-0068&contentType=pdf). The EPA approved Rule 1138 into 
the SIP on July 11, 2011 (66 FR 36170).
    \43\ Rule 1155 (as amended May 2, 2014), paragraph (e)(6). The 
EPA approved Rule 1155 into the SIP on March 16, 2015 (80 FR 13495).
    \44\ SCAQMD Test Method 5.1, ``Determination of Particulate 
Matter Emissions from Stationary Sources Using a Wet Impingement 
Train,'' March 1989; SCAQMD Test Method 5.2, ``Determination of 
Particulate Matter Emissions from Stationary Sources Using Heated 
Probe and Filter,'' March 1989; and SCAQMD Test Method 5.3, 
``Determination of Particulate Matter Emissions from Stationary 
Sources Using an in-Stack Filter,'' October 2005.
---------------------------------------------------------------------------

3. The EPA's Evaluation and Proposed Action
    The emissions inventories in the 2016 PM2.5 Plan were 
made available to the public for comment and were subject to public 
hearing at both the District and State levels.\45\
---------------------------------------------------------------------------

    \45\ SCAQMD Board Resolution 17-2, 3 and CARB Resolution 17-8, 
4.
---------------------------------------------------------------------------

    The inventories in the 2016 PM2.5 Plan are based on the 
most current and accurate information available to the State and 
District at the time the Plan and its inventories were being developed, 
including the latest EPA-approved version of California's mobile source 
emissions model that was available to the State and District at the 
time they were developing the Plan, EMFAC2014, and the EPA's most 
recent AP-42 methodology for paved road dust.\46\ The inventories 
comprehensively address all source categories in the South Coast and 
were developed consistent with the EPA's regulations and inventory 
guidance. In accordance with 40 CFR 51.1008(a), the 2012 base year is 
one of the three years for which monitored data were used for 
designating the area, and it represents actual annual average emissions 
of all sources within the nonattainment area. Direct PM2.5 
and all PM2.5 precursors are included in the inventories, 
and filterable and condensable direct PM2.5 emissions are 
identified separately. For these reasons, we are proposing to approve 
the 2012 base year emissions inventory in the 2016 PM2.5 
Plan as meeting the requirements of CAA section 172(c)(3) and 40 CFR 
51.1008. We are also proposing to find that the future year baseline 
inventories in the Plan satisfy the requirements of 40 CFR 
51.1008(a)(2) and 51.1012(a)(2) and provide an adequate basis for the 
RACM, RFP, and impracticability demonstrations in the 2016 
PM2.5 Plan.\47\
---------------------------------------------------------------------------

    \46\ SCAG's on-road emissions inventory includes power take off 
(PTO) as part of the heavy-duty truck category, whereas CARB's motor 
vehicle emissions budgets (MVEB) includes PTO as a standalone 
vehicle category. See email dated July 9, 2019, from Nesamani 
Kalandiyur, CARB, to Karina O'Connor, EPA. As a result, SCAG's on-
road emissions estimates used in the air quality modeling are 
slightly lower than CARB's MVEBs and the modeled air quality 
concentrations in the 2016 PM2.5 Plan are biased slightly 
low. Thus, the modeled concentrations are conservative and 
consistent with the District's conclusion that attainment by the 
Moderate area attainment date of December 31, 2021 is impracticable.
    \47\ The baseline emissions projections in the 2016 
PM2.5 Plan assume implementation of CARB's Zero Emissions 
Vehicle (ZEV) sales mandate and greenhouse gas (GHG) standards, 
based on the approved EMFAC2014 model and assumptions that were 
available at the time of the SIP's development. 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 of CARB's ZEV sales mandate and 
vehicle GHG standards. 84 FR 51310 (September 27, 2019). 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 South Coast 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 demonstration 
that it is impracticable for the South Coast 2012 PM2.5 
Moderate area to attain by the Moderate area attainment date of 
December 31, 2021.
---------------------------------------------------------------------------

B. PM2.5 Precursors

1. Requirements for the Control of PM2.5 Precursors
    The provisions of subpart 4 of part D, title I of the CAA do not 
define the term ``precursor'' for purposes of PM2.5, nor do 
they explicitly require the control of any specifically identified PM 
precursor. The statutory definition of ``air pollutant'' in CAA section 
302(g), 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.'' The EPA has identified 
NOX, SO2, VOC, and ammonia as precursors to the 
formation of PM2.5. Accordingly, the attainment plan 
requirements of subpart 4 apply to emissions of all four precursor 
pollutants and direct PM2.5 from all types of stationary, 
area, and mobile sources, except as otherwise provided in the Act 
(e.g., in CAA section 189(e)).
    Section 189(e) of the Act requires that the control requirements 
for major stationary sources of direct PM10 (which includes 
PM2.5) also apply to major stationary sources of 
PM10 precursors, except where the Administrator determines 
that such sources do not contribute significantly to PM10 
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, RACT, best available control measures 
(BACM) and best available control technology (BACT), most stringent 
measures (MSM), and new source review (NSR)) for sources of direct 
PM2.5 and PM2.5 precursor emissions. Although 
section 189(e) explicitly addresses only major stationary sources, the 
EPA interprets the Act as authorizing it also to determine, under 
appropriate circumstances, that regulation of specific PM2.5 
precursors from other source categories in a given nonattainment area 
is not necessary. For example, under the EPA's longstanding 
interpretation of the control requirements that apply to stationary and 
mobile sources of PM10 precursors in the nonattainment area 
under CAA section 172(c)(1) and subpart 4,\48\ a state may demonstrate 
in a SIP submission that control of a certain precursor pollutant is 
not necessary in light of its insignificant contribution to ambient 
PM10 levels in the nonattainment area.\49\
---------------------------------------------------------------------------

    \48\ General Preamble, 13539-13542.
    \49\ Courts have upheld this approach to the requirements of 
subpart 4 for PM10. See, e.g., Assoc. of Irritated 
Residents v. EPA, et al., 423 F.3d 989 (9th Cir. 2005).
---------------------------------------------------------------------------

    Under the PM2.5 SIP Requirements Rule, a state may elect 
to submit to the EPA a ``comprehensive precursor demonstration'' for a 
specific nonattainment area to show that emissions of a particular 
precursor from all existing sources located in the nonattainment area 
do not contribute

[[Page 40032]]

significantly to PM2.5 levels that exceed the standard in 
the area.\50\ If the EPA determines that the contribution of the 
precursor to PM2.5 levels in the area is not significant and 
approves the demonstration, the state is not required to control 
emissions of the relevant precursor from existing sources in the 
attainment plan.\51\
---------------------------------------------------------------------------

    \50\ 40 CFR 51.1006(a)(1).
    \51\ Id.
---------------------------------------------------------------------------

    We are evaluating the 2016 PM2.5 Plan in accordance with 
the presumption embodied within subpart 4 that all PM2.5 
precursors must be addressed in the State's evaluation of potential 
control measures, unless the State adequately demonstrates that 
emissions of a particular precursor or precursors do not contribute 
significantly to ambient PM2.5 levels that exceed the 
PM2.5 NAAQS in the nonattainment area. In reviewing any 
determination by the State to exclude a PM2.5 precursor from 
the required evaluation of potential control measures, we consider both 
the magnitude of the precursor's contribution to ambient 
PM2.5 concentrations in the nonattainment area and the 
sensitivity of ambient PM2.5 concentrations in the area to 
reductions in emissions of that precursor.
2. Control of PM2.5 Precursors in the 2016 PM2.5 
Plan
    The 2016 PM2.5 Plan discusses the five primary 
pollutants that contribute to the mass of the ambient aerosol (i.e., 
directly emitted PM2.5, NOX, SOX, VOC, 
and ammonia), and states that various combinations of reductions in 
these pollutants could all provide a path to clean air.\52\ The Plan 
assesses and presents the relative value of each ton of precursor 
emission reductions, considering the resulting ambient improvements in 
PM2.5 air quality expressed in micrograms per cubic 
meter.\53\ As presented in the weight of evidence discussion, trends in 
PM2.5 and NOX emissions suggest a direct response 
between lower emissions and improved air quality. The Community 
Multiscale Air Quality (CMAQ) model simulations in the 2016 
PM2.5 Plan provide a set of response factors for direct 
PM2.5, NOX, SOX, and VOCs, based on 
improvements to ambient PM2.5 levels resulting from 
reductions of each pollutant. The contribution of ammonia emissions is 
embedded as a component of the NOX and SOX 
factors because ammonium nitrate and ammonium sulfate are the resultant 
particulate species formed in the atmosphere.
---------------------------------------------------------------------------

    \52\ 2016 PM2.5 Plan, VI-F-1 and V-6-61.
    \53\ Id. at VI-A-15.
---------------------------------------------------------------------------

    The 2016 PM2.5 Plan describes how reductions in 
NOX, SOX, VOC, and ammonia emissions contribute 
to attainment of the PM2.5 standard in the South Coast area 
and contains the District's evaluation of available control measures 
for all four of these PM2.5 precursor pollutants, in 
addition to direct PM2.5, consistent with the regulatory 
presumptions under subpart 4. The 2016 PM2.5 Plan also 
contains a discussion of the control requirements applicable to major 
stationary sources under CAA section 189(e).\54\
---------------------------------------------------------------------------

    \54\ Id., Appendix VI-F. In a separate rulemaking to approve 
revisions to SCAQMD's NNSR program, the EPA determined that the 
control requirements applicable under the SCAQMD SIP to major 
stationary sources of direct PM2.5 also apply to major 
stationary sources of NOX, SOX, and VOC, and 
that major stationary sources of ammonia do not contribute 
significantly to PM2.5 levels that exceed the 
PM2.5 standards in the area. (80 FR 24821, May 1, 2015). 
This rulemaking addressed the control requirements of CAA section 
189(e) only for NNSR purposes and not for attainment planning 
purposes under subparts 1 and 4 of part D, title I of the Act.
---------------------------------------------------------------------------

3. The EPA's Evaluation and Proposed Action
    Based on a review of the information provided in the 2016 
PM2.5 Plan and other information available to the EPA, we 
agree with the State's conclusion that all four chemical precursors to 
the formation of PM2.5 must be regulated for purposes of 
attaining the 2012 PM2.5 NAAQS in the South Coast area. We 
discuss the State's evaluation of potential control measures for direct 
PM2.5, NOX, SOX, VOC, and ammonia in 
section V.D.

C. Air Quality Modeling

1. Requirements for Air Quality Modeling
    Section 189(a)(1)(B) of the CAA requires each state in which a 
Moderate area is located to submit a plan that includes a demonstration 
(including air quality modeling) either (i) that the plan will provide 
for attainment of the PM2.5 NAAQS by the applicable 
attainment date, or (ii) that attainment by that date is impracticable. 
The 2016 PM2.5 Plan includes a demonstration that attainment 
by the Moderate attainment date is impracticable.
    The EPA's PM2.5 modeling guidance \55\ (``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.\56\ The modeled response to the emission 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 PM2.5, and for each quarter of the year, to reflect their 
differing responses to seasonal meteorological conditions and 
emissions. Because each species is handled separately, before applying 
an RRF, the base year design value must be speciated using available 
chemical species measurements--that is, each day's measured 
PM2.5 design value must be split into its species 
components. The Modeling Guidance provides additional detail on the 
recommended approach.\57\
---------------------------------------------------------------------------

    \55\ 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, 
PM2.5, and Regional Haze,'' (``Modeling Guidance''), and 
Memorandum dated June 28, 2011 from Tyler Fox, Air Quality Modeling 
Group, OAQPS, EPA, to Regional Air Program Managers, EPA, Subject: 
``Update to the 24 Hour PM2.5 NAAQS Modeled Attainment 
Test,'' (``Modeling Guidance Update'').
    \56\ 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. Note that CARB sometimes 
uses ``base year'' synonymously with ``base case'' and ``reference 
year'' instead of ``base year.''
    \57\ Modeling Guidance, section 4.4, ``What is the Modeled 
Attainment Tests for the Annual Average PM2.5 NAAQS.''
---------------------------------------------------------------------------

    The EPA has not issued modeling guidance specific to 
impracticability demonstrations but believes that a state seeking to 
make such a demonstration generally should provide air quality modeling 
similar to that required for an attainment demonstration.\58\ The main 
difference is that for an impracticability demonstration, the 
implementation of the SIP control strategy (including

[[Page 40033]]

RACM) does not result in attainment of the standard by the Moderate 
area attainment date.
---------------------------------------------------------------------------

    \58\ 81 FR 58010, 58048.
---------------------------------------------------------------------------

    For an attainment demonstration, a thorough review of all modeling 
inputs and assumptions (including consistency with EPA guidance) is 
especially important because the modeling must ultimately support a 
conclusion that the plan (including its control strategy) will provide 
for timely attainment of the applicable NAAQS. In contrast, for an 
impracticability demonstration, the end point is a reclassification to 
Serious, which triggers the requirement for a new Serious area 
attainment plan with a new air quality modeling analysis, and a new 
control strategy.\59\ Thus, the Serious area planning process would 
provide an opportunity to refine the modeling analysis and/or correct 
any technical shortcomings in the impracticability demonstration. 
Therefore, the burden of proof will generally be lower for an 
impracticability demonstration compared to an attainment 
demonstration.\60\
---------------------------------------------------------------------------

    \59\ CAA section 189(b)(1).
    \60\ 81 FR 58010, 58049.
---------------------------------------------------------------------------

2. Air Quality Modeling in the 2016 PM2.5 Plan
    Air quality modeling is discussed in Chapter 5 and Appendix V of 
the 2016 PM2.5 Plan. A brief description of the modeling and 
our evaluation of it follows. More detailed information about the 
modeling in the Plan is available in section III of our technical 
support document (TSD) for this proposed action.\61\
---------------------------------------------------------------------------

    \61\ EPA, Region IX, Air Division, ``Technical Support Document, 
Proposed Action on the South Coast Moderate Area State 
Implementation Plan and Proposed Reclassification as Serious 
Nonattainment for the 2012 PM2.5 Standard,'' April 2020.
---------------------------------------------------------------------------

Annual PM2.5 Modeling Approach
    The District conducted CMAQ \62\ simulations for each day in the 
2012 base year. It generated site- and species-specific RRFs for the 
ammonium ion, nitrate ion, sulfate ion, organic carbon, elemental 
carbon, sea salt, and a combined grouping of other primary 
PM2.5 material for each future year simulation, and 
calculated future year design values by multiplying the species- and 
site-specific RRFs by the corresponding quarterly mean component 
concentration. The District summed the quarterly mean components to 
determine quarterly mean PM2.5 concentrations, which it 
subsequently averaged to determine the annual design values. The future 
year design values reflect the weighted quarterly average concentration 
from the projections of five years of data. The District projected 
future year annual PM2.5 design values for the 2021 Moderate 
area attainment year and the 2025 Serious area attainment year, for the 
2012 PM2.5 standard of 12 [micro]g/m\3\.\63\
---------------------------------------------------------------------------

    \62\ CMAQ Version 5.0.2.
    \63\ The District also projected future year annual 
PM2.5 design values for 2023.
---------------------------------------------------------------------------

Future Air Quality
    Simulations of 2021 baseline emissions (no additional controls) and 
2021 control emissions were conducted to assess future annual 
PM2.5 levels in the South Coast air basin. The 2021 baseline 
simulation used emission levels projected from the 2012 base year that 
reflect all adopted control measures to be implemented by December 31, 
2021. The 2021 control simulation reflects the effects of the control 
strategy on future PM2.5 design values. Simulations of both 
the 2021 baseline and 2021 control emissions indicate that the 2012 
annual PM2.5 standard will not be met in the South Coast in 
2021, even when all controls for direct PM2.5 and 
PM2.5 precursors are implemented. The projected 2021 control 
scenario design value is 12.3 [micro]g/m\3\ at Mira Loma, which is 
typically the monitoring site that records the highest PM2.5 
levels in the South Coast air basin.
    Table 2 shows future annual PM2.5 air quality 
projections at the Mira Loma monitoring site and the four other 
PM2.5 monitoring sites equipped with comprehensive 
particulate species characterization. Shown in the table are the base 
year design values for 2012 along with projections for 2021.

    Table 2--Future Annual PM2.5 Air Quality Projections at Selected
              Monitoring Sites in the South Coast Air Basin
                             [[micro]g/m\3\]
------------------------------------------------------------------------
                                                                  2021
               Monitoring site location                  2012    Control
------------------------------------------------------------------------
Anaheim...............................................    10.6       9.1
Fontana...............................................    12.6      10.4
Los Angeles...........................................    12.4      10.6
Mira Loma.............................................    14.9      12.3
Rubidoux..............................................    13.2      10.9
------------------------------------------------------------------------
Source: 2016 PM2.5 Plan, Table 5-5 and Table V-6-6.

3. The EPA's Evaluation and Conclusion
    The EPA evaluated the District's choice of model for the 
impracticability demonstration and the extensive discussion in the Plan 
about modeling procedures, tests, and performance analyses. We find the 
District's analyses consistent with EPA guidance on modeling for 
PM2.5 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 the demonstration of 
impracticability in the 2016 PM2.5 Plan.

D. Reasonably Available Control Measures and Control Strategy

1. Requirements for RACM/RACT and Control Strategies
    The general subpart 1 attainment plan requirement for RACM/RACT is 
described in CAA section 172(c)(1), which requires that attainment plan 
submissions ``provide for the implementation of all reasonably 
available control measures as expeditiously as practicable (including 
such reductions in emissions from existing sources in the area as may 
be obtained through the adoption, at a minimum, of reasonably available 
control technology)'' and provide for attainment of the NAAQS.
    The attainment planning requirements specific to PM2.5 
under subpart 4 likewise impose upon states with nonattainment areas 
classified as Moderate an obligation to develop attainment plans that 
require RACM/RACT on sources of direct PM2.5 and all 
PM2.5 plan precursors. CAA section 189(a)(1)(C) requires 
that Moderate area PM2.5 SIPs contain provisions to assure 
that RACM/RACT are implemented no later than four years after 
designation of the area. The EPA reads CAA section 172(c)(1) and 
189(a)(1)(C) together to require that attainment plans for Moderate 
nonattainment areas provide for the implementation of RACM/RACT for 
existing sources of PM2.5 and those PM2.5 
precursors subject to control in the nonattainment area as 
expeditiously as practicable but no later than four years after 
designation.\64\
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    \64\ This interpretation is consistent with guidance provided in 
the General Preamble, 13540.
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    The PM2.5 SIP Requirements Rule defines RACM as ``any 
technologically and economically feasible measure that can be 
implemented in whole or in part within 4 years after the effective date 
of designation of a PM2.5 nonattainment area and that 
achieves permanent and enforceable reductions in direct 
PM2.5 emissions and/or PM2.5 plan precursor 
emissions from sources in the area. RACM includes reasonably available 
control technology (RACT).'' \65\ The EPA has historically defined RACT 
as the lowest emission limitation that a particular stationary source 
is capable of meeting by the application of control

[[Page 40034]]

technology (e.g., devices, systems, process modifications, or other 
apparatus or techniques that reduce air pollution) that is reasonably 
available considering technological and economic feasibility.\66\
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    \65\ 81 FR 58010, 58035.
    \66\ General Preamble, 13541, and 57 FR 18070, 18073-18074.
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    Under the PM2.5 SIP Requirements Rule, those control 
measures that otherwise meet the definition of RACM but ``can only be 
implemented in whole or in part during the period beginning 4 years 
after the effective date of designation of a nonattainment area and no 
later than the end of the sixth calendar year following the effective 
date of designation of the area'' must be adopted and implemented as 
``additional reasonable measures.'' \67\
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    \67\ 40 CFR 51.1000, 51.1009(a)(4)(i)(B), and 
51.1009(a)(4)(ii)(B).
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    States must provide written justification in a SIP submission for 
eliminating potential control options from further review on the basis 
of technological or economic infeasibility.\68\ An evaluation of 
technological feasibility may include consideration of factors such as 
a source's process and operating conditions, raw materials, physical 
plant layout, and non-air quality and energy impacts (e.g., increased 
water pollution, waste disposal, and energy requirements).\69\ An 
evaluation of economic feasibility may include consideration of factors 
such as cost per ton of pollution reduced (cost-effectiveness), capital 
costs, and operating and maintenance costs.\70\ Absent other 
indications, the EPA presumes that it is reasonable for similar sources 
to bear similar costs of emission reductions. Economic feasibility of 
RACM/RACT is thus largely informed by evidence that other sources in a 
source category have in fact applied the control technology, process 
change, or measure in question in similar circumstances.\71\
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    \68\ 40 CFR 51.1009(a)(3).
    \69\ 40 CFR 51.1009(a)(3); see also 57 FR 18070, 18073-18074.
    \70\ Id.
    \71\ 57 FR 18070, 18074.
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    Consistent with these requirements, SCAQMD must implement RACM, 
including RACT, for direct PM2.5 emission sources no later 
than April 15, 2019, and must implement additional reasonable measures 
for these sources no later than December 31, 2021.
    The CAA allows for approval of enforceable commitments that are 
limited in scope where circumstances exist that warrant the use of such 
commitments in place of adopted measures.\72\ Specifically, section 
110(a)(2)(A) of the CAA provides that each SIP ``shall include 
enforceable emission limitations and other control measures, means or 
techniques . . . as well as schedules and timetables for compliance, as 
may be necessary or appropriate to meet the applicable requirements of 
the Act.'' Section 172(c)(6) of the Act, which applies to nonattainment 
area SIPs, is virtually identical to section 110(a)(2)(A).\73\ 
Commitments approved by the EPA under CAA section 110(k)(3) are 
enforceable by the EPA and citizens under CAA sections 113 and 304, 
respectively. Additionally, if a state fails to meet its commitments, 
the EPA may make a finding of failure to implement the SIP under CAA 
section 179(a)(4), which starts an 18-month period for the state to 
correct the non-implementation before mandatory sanctions are imposed.
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    \72\ In the past, the EPA has approved enforceable commitments 
and courts have enforced these actions against states that failed to 
comply with those commitments. See, e.g., American Lung Ass'n of 
N.J. v. Kean, 670 F. Supp. 1285 (D.N.J. 1987), aff'd, 871 F.2d 319 
(3rd Cir. 1989); NRDC, Inc. v. N.Y. State Dept. of Env. Cons., 668 
F. Supp. 848 (S.D.N.Y. 1987); Citizens for a Better Env't v. 
Deukmejian, 731 F. Supp. 1448, recon. granted in par, 746 F. Supp. 
976 (N.D. Cal. 1990); Coalition for Clean Air v. South Coast Air 
Quality Mgt. Dist., No. CV 97-6916-HLH, (C.D. Cal. Aug. 27, 1999).
    \73\ The language in sections 110(a)(2)(A) and 172(c)(6) is 
quite broad, allowing a SIP to contain any enforceable ``means or 
techniques'' that the EPA determines are ``necessary or 
appropriate'' to meet CAA requirements, such that the area will 
attain as expeditiously as practicable, but no later than the 
designated date. Furthermore, the express allowance for ``schedules 
and timetables'' demonstrates that Congress understood that all 
required controls might not be in place when a SIP is approved.
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    Once the EPA determines that circumstances warrant consideration of 
an enforceable commitment to satisfy a CAA requirement, it considers 
three factors in determining whether to approve the enforceable 
commitment: (a) Does the commitment address a limited portion of the 
CAA requirement; (b) is the state capable of fulfilling its commitment; 
and (c) is the commitment for a reasonable and appropriate period of 
time.\74\
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    \74\ The Fifth Circuit Court of Appeals upheld the EPA's 
interpretation of CAA sections 110(a)(2)(A) and 172(c)(6) and the 
Agency's use and application of the three-factor test in approving 
enforceable commitments in the 1-hour ozone SIP for Houston-
Galveston. BCCA Appeal Group et al. v. EPA et al., 355 F.3d 817 (5th 
Cir. 2003). More recently, the Ninth Circuit Court of Appeals upheld 
the EPA's approval of enforceable commitments in ozone and 
PM2.5 SIPs for the San Joaquin Valley, based on the same 
three factor test. Committee for a Better Arvin, et al. v. EPA, 786 
F.3d 1169 (9th Cir. 2015).
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2. Control Strategy in the 2016 PM2.5 Plan
    For purposes of evaluating the 2016 PM2.5 Plan, we have 
divided the measures relied on to satisfy the applicable control 
requirements into two categories: Baseline measures and control 
strategy measures.
    As the term is used here, baseline measures are federal, State, and 
District rules and regulations adopted prior to December 2015 for 
District rules, and prior to November 2015 for CARB rules (i.e., prior 
to the development of the 2016 PM2.5 Plan) that continue to 
achieve emission reductions through the Moderate area attainment year 
of 2021 and beyond.\75\ The Plan describes many of these measures in 
Chapter 4, Appendix III, Appendix IV-B, Appendix IV-C, and Appendix 
VI.\76\ Reductions from these baseline measures are incorporated into 
the baseline inventory and reductions from the District measures in the 
plan are individually quantified in Appendix III, Table III-2-2B. 
According to the Plan, baseline measures provide most of the emission 
reductions projected to occur between the 2012 base year and the 2022 
post-attainment milestone year.\77\
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    \75\ These measures are typically rules that have compliance 
dates occuring after the adoption date of a plan and mobile source 
measures that achieve reductions as older engines are replaced 
through attrition (e.g., through fleet turnover).
    \76\ See also, email dated September 12, 2019 from Kalam Cheung, 
SCAQMD, to Ashley Graham, EPA Region IX, attaching spreadsheet 
entitled ``Draft Rule Adoption since 2016 AQMP 20190809.xlsx.''
    \77\ 2016 PM2.5 Plan, Chapter 4 and Appendix V.
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    Control strategy measures are the new rules, rule revisions, 
commitments, and other measures that provide the additional increment 
of emission reductions needed beyond the baseline measures to provide 
for attainment, to demonstrate RFP, to meet the RACM/RACT requirement, 
or to provide for contingency measures. Beyond the reductions from the 
Plan's baseline measures as discussed above, the remaining reductions 
needed for RFP and attainment \78\ are to be achieved through the 
District's enforceable commitments to achieve emission reductions in 
the South Coast nonattainment area. The Plan identifies the control 
measures that are expected to achieve those emission reductions, 
several of which are identified as ``additional reasonable measures'' 
because they are to be implemented

[[Page 40035]]

after the RACM deadline (i.e., after the four-year period following 
designation but before the Moderate area attainment date). Below we 
discuss the District's RACM/RACT evaluation, additional reasonable 
measures identified in the plan, and the District's commitments to 
achieve emission reductions through new control measures to attain the 
2012 PM2.5 NAAQS by the December 31, 2025 Serious area 
attainment date.
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    \78\ The 2016 PM2.5 Plan contains a demonstration 
that attainment of the 2012 PM2.5 NAAQS by the December 
31, 2021 Moderate area attainment date is impracticable and 
identifies December 31, 2025 as the most expeditious date by which 
the South Coast area can attain this standard. 2016 PM2.5 
Plan, Chapter 5 and Appendix V.
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a. RACM/RACT Analysis in the 2016 PM2.5 Plan
    The 2016 PM2.5 Plan's RACM/RACT evaluation for direct 
PM2.5, NOX, SOX, VOC, and ammonia 
sources is presented in Appendix VI. The District, CARB, and SCAG, the 
local metropolitan planning organization (MPO), each undertook a 
process to identify and evaluate potential measures that could 
contribute to expeditious attainment of the 2012 PM2.5 
standard in the South Coast nonattainment area. We describe each of 
these processes below.
i. The District's RACM Analysis
    The District's RACM demonstration for the 2012 PM2.5 
NAAQS focuses on stationary and area source controls and is described 
in Appendix VI-A of the 2016 PM2.5 Plan.
    In the years prior to the adoption of the 2016 PM2.5 
Plan, the District developed and implemented comprehensive plans (e.g., 
the 2012 Air Quality Management Plan) to provide for attainment of the 
PM2.5 and ozone NAAQS. These plans have resulted in the 
District's adoption of many new rules and amendments to existing rules 
for stationary and area sources. In addition, although the District 
does not have authority to directly regulate emissions from mobile 
sources, the District has implemented control strategies to indirectly 
reduce emissions from mobile sources. These regulations and strategies 
have yielded significant emission reductions from sources under the 
District's jurisdiction.
    In the 2016 PM2.5 Plan, the District conducted a multi-
step process to identify additional candidate RACM measures that are 
technologically and economically feasible. As a first step in the RACM 
analysis, the District developed a detailed emissions inventory of the 
sources of direct PM2.5 and PM2.5 precursors. An 
up-to-date and comprehensive emissions inventory is essential to 
develop control measures that effectively reduce air pollution. Details 
on the methodology and development of the emissions inventory are 
discussed in Chapter 3 and Appendix III of the 2016 PM2.5 
Plan. A total of 75 major source categories are included in the base 
year emissions inventory.\79\
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    \79\ 2016 PM2.5 Plan, Table VI-A-3.
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    Based on these inventories, the District identified several source 
categories as key emission sources in the South Coast nonattainment 
area for the 2012 PM2.5 NAAQS, including consumer products, 
livestock wastes, and numerous mobile source categories.\80\ For the 
key stationary source categories under SCAQMD's jurisdiction, the 
District compared existing control measures with requirements in 
federal and state regulations and guidance, as well as with analogous 
rules in other air districts to identify potential control measures. 
Furthermore, to demonstrate that the SCAQMD considered all additional 
candidate measures that are available and technologically and 
economically feasible, the District conducted the following seven-step 
analysis:
---------------------------------------------------------------------------

    \80\ Id., Table VI-A-8.
---------------------------------------------------------------------------

    (1) Held an Air Quality Technology Symposium to solicit new ideas 
for feasible control measures in the South Coast air basin;
    (2) conducted a RACT analysis to identify SCAQMD rules that are 
less stringent than the EPA control technique guidelines (CTGs) or 
analogous rules in other air districts;
    (3) reviewed EPA technical support documents for previously 
adopted/amended rules submitted for approval into the California SIP;
    (4) reviewed control measures adopted during 2012-2015 in other 
areas (i.e., Ventura County, San Francisco Bay Area, San Joaquin 
Valley, Sacramento Metropolitan, Dallas Fort-Worth, Houston-Galveston-
Brazoria, New York, and New Jersey) to evaluate whether control 
technologies deemed available and cost-effective in those areas would 
be feasible for use in the South Coast air basin;
    (5) reevaluated control measures that the District had found to be 
technologically or economically infeasible as part of the RACM analysis 
for the 2012 AQMP;
    (6) reviewed the EPA's Menu of Control Measures (MCM); \81\ and
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    \81\ EPA, Menu of Control Measures,
    http://www3.epa.gov/ttn/naaqs/pdfs/MenuOfControlMeasures.pdf, as 
of December 1, 2015.
---------------------------------------------------------------------------

    (7) reviewed the EPA's March 2013 ``Strategies for Reducing Wood 
Smoke'' guidance document to identify regulatory options for reducing 
residential wood smoke.
    Based on its RACM/RACT evaluation for stationary and area sources 
under its jurisdiction as described above, the District found that its 
current rules and regulations are generally equivalent to, or more 
stringent than, those developed by other air districts with respect to 
emissions of PM2.5 and PM2.5 precursors.\82\ The 
District identified a list of potential control measures for reducing 
emissions further,\83\ and evaluated these potential additional control 
measures to determine whether implementation of the measures would be 
technologically and economically feasible in the South Coast. In 
addition, the District considered other available control options that 
can only be implemented after the four-year deadline for RACM/RACT, but 
before the end of the sixth calendar year following designation, i.e., 
additional reasonable measures.
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    \82\ 2016 PM2.5 Plan, VI-A-36 to VI-A-37.
    \83\ Id., Table VI-A-11.
---------------------------------------------------------------------------

    The District identified four additional control measures with 
quantifiable emission reductions to be implemented for the purpose of 
meeting the 2012 PM2.5 NAAQS. The Plan contains a commitment 
by the District to adopt and implement these or substitute measures as 
additional reasonable measures in 2020.\84\ We discuss the District's 
commitment in further detail in section V.D.2.b.
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    \84\ SCAQMD, Governing Board Resolution No. 17-2 (March 3, 
2017), 9, and 2016 PM2.5 Plan, Table 4-7 and Table 4-8 
(identifying BCM-04, BCM-10, CMB-02 and CMB-03 as new control 
measures to be implemented by 2020 for PM2.5 purposes).
---------------------------------------------------------------------------

    The District has also included new commitments in the 2016 
PM2.5 Plan to achieve specific amounts of emission 
reductions from NOX and ammonia sources in the South Coast 
area. Specifically, the District has committed to adopt and submit 
measures that will achieve 2.5 tons per day (tpd) of reductions in 
NOX emissions and 0.3 tpd of reductions in ammonia emissions 
by 2020, and 20.5 tpd of reductions in NOX emissions by 
2022, as part of the control strategy for attaining the 
PM2.5 NAAQS by 2025.\85\ The District expects

[[Page 40036]]

to meet these emission reduction commitments by adopting new control 
measures and programs and strengthening existing control measures, such 
as those identified in Table 4-7 and Table 4-8 of the Plan and in a 
supplemental update to the control strategy submitted September 12, 
2019 (``Control Strategy Updates'').\86\ More information about the 
District's enforceable commitments and the specific control measures 
anticipated to meet them is included in section V.D.2.c of this 
proposed rule.
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    \85\ SCAQMD, Governing Board Resolution No. 17-2 (March 3, 
2017), 9; 2016 PM2.5 Plan, Table 4-8; and email dated 
September 12, 2019 from Kalam Cheung, SCAQMD, to Ashley Graham, EPA 
Region IX, attaching spreadsheet entitled ``Draft Rule Adoption 
since 2016 AQMP 20190809.xlsx'' (``Control Strategy Updates''). 
Table 4-8 of the Plan identifies 5.8 tpd of NOX 
reductions to be achieved by 2022 but is supplemented by the Control 
Strategy Updates, which identify 20.5 tpd of NOX 
reductions to be achieved by 2022 as part of the District's 
aggregate tonnage commitment. Control Strategy Updates, ``Summary'' 
tab (``South Coast AQMD Reasonable Further Progress for 2012 Annual 
PM2.5 Standard''). Table 4-8 of the Plan also identifies 
0.3 tpd ammonia reductions and 28 tpd NOX reductions to 
be achieved for purposes of attaining the PM2.5 NAAQS by 
2025 and 3.3 tpd PM2.5 reductions to be achieved for 
contingency measure purposes in 2025.
    \86\ Control Strategy Updates, ``Summary'' tab (``South Coast 
AQMD Reasonable Further Progress for 2012 Annual PM2.5 
Standard'').
---------------------------------------------------------------------------

    We provide below an evaluation of several State and District 
measures for key stationary and area source categories. We provide a 
more detailed evaluation of the District's regulations in our TSD,\87\ 
together with recommendations for future improvements to these rules.
---------------------------------------------------------------------------

    \87\ EPA, Region IX, Air Division, ``Technical Support Document, 
Proposed Action on the South Coast Moderate Area State 
Implementation Plan and Proposed Reclassification as Serious 
Nonattainment for the 2012 PM2.5 Standard,'' April 2020.
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ii. State and District Measures for Stationary and Area Sources
Consumer Products
    CARB and the SCAQMD both have well-established programs to regulate 
VOC emissions from consumer products used by both household and 
institutional consumers, including detergents; cleaning compounds; 
polishes; floor finishes; cosmetics; personal care products; home, 
lawn, and garden products; disinfectants; sanitizers; aerosol paints; 
and automotive specialty products. Specifically, CARB has adopted three 
regulations that establish VOC and reactivity limits for 129 consumer 
product categories.\88\ The first regulation (Article 1) covers the 
categories of antiperspirants and deodorants. The second regulation 
(Article 2) covers numerous categories and is simply called the 
``General Consumer Products Regulation.'' The third regulation (Article 
3) covers categories of aerosol coatings. The EPA approved amendments 
to these regulations into the California SIP on October 17, 2014.\89\
---------------------------------------------------------------------------

    \88\ These regulations are codified in the California Code of 
Regulations, Title 17, Division 3, Chapter 1, Subchapter 8.5--
Consumer Products; Article 2--Consumer Products.
    \89\ 79 FR 62346.
---------------------------------------------------------------------------

    The SCAQMD also regulates certain categories of consumer products, 
including architectural coatings, wood products, solvents and 
degreasers, consumer paint thinners, and inks.\90\ As an example, we 
discuss South Coast's implementation of Rule 1113 (``Architectural 
Coatings'') below.
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    \90\ See, e.g., South Coast Rule 1107 (``Coating of Metal Parts 
and Products''), approved into the SIP on November 24, 2008 (73 FR 
70883); South Coast Rule 1122 (``Solvent Degreasers''), approved 
into the SIP on February 8, 2006 (71 FR 6350); and South Coast Rule 
1130 (``Graphic Arts''), approved into the SIP on July 14, 2015 (80 
FR 40915).
---------------------------------------------------------------------------

    Based on our evaluation of the information about these programs in 
the 2016 PM2.5 Plan, we agree with the State's and 
District's conclusion that these SIP-approved regulations implement 
RACM for the control of VOCs from consumer products.
Architectural Coatings
    SCAQMD Rule 1113 (``Architectural Coatings''), amended February 5, 
2016, establishes VOC content limits for paints and other architectural 
coating products and establishes workplace standards for architectural 
coating operations. The EPA approved Rule 1113, as amended, into the 
California SIP on November 29, 2018.\91\
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    \91\ 83 FR 61326.
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    In the 2016 PM2.5 Plan, the District compared the 
requirements of Rule 1113, as amended September 6, 2013,\92\ to 
analogous requirements implemented in other California air districts 
between 2000 and 2015. The District's evaluation included the 
requirements of Sacramento Metropolitan Air Quality Management 
District's Rule 442, as amended September 24, 2015. Based on this 
evaluation, the District concluded that Rule 1113, as amended September 
6, 2013, is generally equivalent to the requirements in other air 
districts.
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    \92\ The EPA approved Rule 1113, as amended June 3, 2011, into 
the SIP on March 26, 2013. 78 FR 18244. Since then, the EPA has 
approved a more stringent version of Rule 1113, as amended February 
5, 2016, into the SIP. 83 FR 61326 (November 29, 2018).
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    The District's February 5, 2016 amendment to Rule 1113 strengthened 
the rule by eliminating its exemption for small containers. According 
to a SCAQMD staff report, the small container exemption represented one 
percent of sales and an estimated twenty percent of total VOC 
emissions.\93\ According to this report, the 2016 rule revision was 
expected to achieve an estimated VOC reduction of 0.88 tpd by January 
1, 2019. The EPA approved this amended rule into the California SIP on 
November 29, 2018.\94\
---------------------------------------------------------------------------

    \93\ SCAQMD Final Staff Report, ``Proposed Amended Rule 1113--
Architectural Coatings,'' February 2016, 22.
    \94\ 83 FR 61326.
---------------------------------------------------------------------------

    Based on our evaluation of the information provided in the 2016 
PM2.5 Plan and additional information obtained during our 
review of the Plan, we agree with the SCAQMD's conclusion that Rule 
1113 implements RACM for the control of VOCs from architectural 
coatings.
Confined Animal Facilities and Livestock Waste
    SCAQMD Rule 1127 (``Emission Reductions from Livestock Waste''), 
adopted August 6, 2004, and Rule 223 (``Emission Reduction Permits for 
Large Confined Animal Facilities''), adopted June 2, 2006, together 
establish requirements to reduce emissions of ammonia, VOCs, and other 
pollutants emitted from confined animal facilities and related 
operations. The EPA approved Rule 1127 and Rule 223 into the California 
SIP on May 23, 2013 and July 13, 2015, respectively.\95\
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    \95\ 78 FR 30768 (May 23, 2013) and 80 FR 39966 (July 13, 2015).
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    Rule 1127 applies to dairy farms with 50 or more cows, heifers, 
and/or calves and to manure processing operations, such as composting 
operations and anaerobic digesters. The rule requires operators of 
dairy farms and manure processing operations to use specified best 
management practices to reduce pollutant emissions during the removal 
and disposal of manure from corrals, among other things. Rule 223 
applies to large confined animal facilities (LCAFs) and prohibits 
owners/operators of such facilities from building, altering, replacing, 
or operating an LCAF without first obtaining a permit from the 
District. The permit application must include, among other things, an 
emissions mitigation plan that identifies the mitigation measures to be 
implemented at the facility. For each source category covered by the 
rule, owners/operators must implement a prescribed number of mitigation 
measures among a list of options or as approved by the District, CARB, 
and the EPA.
    The District compared the key requirements of Rule 1127 and Rule 
223 to analogous requirements implemented in other parts of California 
and in Idaho. Based on this evaluation, the District concludes that 
Rule 1127 and Rule 223 together establish requirements for confined 
animal facilities and related operations that are generally equivalent 
to the requirements in these other areas. The District also considered 
several additional control methods to further reduce ammonia emissions 
from livestock waste, including application of acidifiers (sodium 
bisulfate), dietary manipulation, feed additives, manure slurry 
injection, and microbial/manure additives. The 2016 PM2.5 
Plan contains a commitment by the District to adopt

[[Page 40037]]

an ammonia control measure for livestock waste in 2019.\96\ The 
proposed measure is identified in the Plan as BCM-04.\97\
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    \96\ SCAQMD, Governing Board Resolution No. 17-2 (March 3, 
2017), 9 and 2016 PM2.5 Plan, Table 4-7.
    \97\ 2016 PM2.5 Plan, Table 4-7 and IV-A-202 to IV-A-
209 (describing BCM-04).
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    Based on our evaluation of the information provided in the 2016 
PM2.5 Plan, we agree with the SCAQMD's conclusion that Rule 
1127 and Rule 223 together implement RACM for the control of ammonia 
and VOCs from confined animal facilities and related operations.
Residential Wood-Burning Devices
    SCAQMD Rule 445 (``Wood-Burning Devices''), amended May 3, 2013, 
establishes requirements for the sale, operation, and installation of 
wood-burning devices within the South Coast air basin that are designed 
to reduce PM emissions from such devices. The EPA approved Rule 445, as 
amended, into the California SIP on September 26, 2013.\98\
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    \98\ 78 FR 59249.
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    Under Rule 445, persons who manufacture, sell, or install wood-
burning devices, commercial firewood sellers, and property owners or 
tenants who operate wood-burning devices are subject to specific 
requirements concerning the types of wood-burning devices that may be 
manufactured, sold, or installed, the types of fuels that may be burned 
in such devices, and labeling requirements. Rule 445 also establishes a 
mandatory winter wood-burning curtailment whenever the Executive 
Officer declares that ambient PM2.5 levels are forecasted to 
exceed 30 [micro]g/m\3\ at specified source receptor areas.\99\
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    \99\ The District has committed to adopt and submit revisions to 
Rule 445 to expand the geographic scope of the mandatory wood-
burning curtailment provisions and to lower the curtailment 
threshold if the EPA makes any of the findings listed in 40 CFR 
51.1014(a). Letter dated March 3, 2020, from Michael Benjamin, CARB, 
to Amy Zimpfer, EPA (enclosing letter dated February 12, 2020, from 
Wayne Nastri, SCAQMD, to Richard Corey, CARB). For more detail on 
the District's commitment, see section V.H of this proposed rule 
(``Contingency Measures'').
---------------------------------------------------------------------------

    The District compared the requirements of Rule 445 to several rules 
implemented elsewhere in California that are designed to limit PM 
emissions from residential wood-burning devices. Based on this review, 
the District concludes that Rule 445 is generally equivalent to these 
other rules. Rule 445 does not require the removal of old wood stoves 
upon resale of a home, as do rules implemented in several other areas, 
but it does contain a prohibition on the installation of any wood-
burning device in new residential developments, except in developments 
where there is no existing infrastructure for natural gas service 
within 150 feet of the property line or those 3,000 or more feet above 
mean sea level. Several other air districts prohibit or limit the 
installation of non-certified wood-burning devices but allow for 
installation of EPA-certified devices in new developments.
    The EPA approved Rule 445 as implementing BACM for the 2006 24-hour 
PM2.5 NAAQS on February 12, 2019.\100\ Since that time, at 
least two other California air districts have revised their wood-
burning rules to incorporate more stringent requirements.\101\ Given 
that these rules were amended well after both the date of CARB's 
submission of the Plan, April 27, 2017, and the statutory deadline for 
this plan submission, October 15, 2016,\102\ we find it reasonable that 
the SCAQMD did not evaluate these additional control requirements as 
part of its RACM analysis in the 2016 PM2.5 Plan. Full 
evaluation of the additional control requirements in these revised 
rules will, however, be required as part of the State/District's BACM 
demonstration for the 2012 PM2.5 NAAQS, which will be due 
within 18 months after the effective date of a final rule reclassifying 
the South Coast area as Serious nonattainment for the 2012 
PM2.5 NAAQS.
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    \100\ 84 FR 3305.
    \101\ San Joaquin Valley Unified Air Pollution Control District 
Rule 4901, amended June 20, 2019, and Bay Area Air Quality 
Management District Rule 6-3, amended November 20, 2019.
    \102\ Section 189(a)(2) of the CAA requires submission of 
Moderate area plans within 18 months after nonattainment 
designations. Because the EPA designated the South Coast as a 
nonattainment area for the 2012 PM2.5 NAAQS effective 
April 15, 2015 (80 FR 2206), California was required to submit a 
Moderate area plan for this area by October 15, 2016.
---------------------------------------------------------------------------

    Based on our evaluation of the information provided in the 2016 
PM2.5 Plan, we agree with the SCAQMD's conclusion that Rule 
445 implements RACM for the control of PM2.5 from 
residential wood-burning devices.
Paved and Unpaved Roads and Livestock Operations
    Rule 1186 (``PM10 Emissions from Paved and Unpaved 
Roads, and Livestock Operations''), amended July 11, 2008, establishes 
requirements to reduce the entrainment of PM as a result of vehicular 
travel on paved and unpaved public roads and livestock operations. The 
EPA approved Rule 1186, as amended, into the California SIP on March 7, 
2012.\103\
---------------------------------------------------------------------------

    \103\ 77 FR 13495.
---------------------------------------------------------------------------

    Under Rule 1186, owners and operators of paved roads with average 
daily vehicle trips exceeding certain thresholds must remove visible 
roadway accumulation within specified periods of time and provide 
curbing or paved shoulders of certain widths when constructing new or 
widened roads. Rule 1186 also requires local government agencies that 
own or maintain paved roads to procure only certified street sweeping 
equipment for routine street sweeping; establishes requirements for 
owners and operators of certain unpaved roads to pave, apply chemical 
stabilization, or install signs to reduce vehicular speeds; and 
requires owners and operators of livestock operations to cease hay 
grinding activities during certain times of day, if visible emissions 
extend more than 50 feet from a hay grinding source.
    The District compared the key requirements of Rule 1186 to 
analogous requirements implemented in other parts of California and in 
Nevada. Based on this evaluation, the District concludes that Rule 1186 
is generally equivalent to the requirements in these other areas. To 
further reduce PM2.5 emissions in areas with high vehicular 
activity, the District also considered several additional control 
techniques, such as increasing the frequency of street sweeping with 
certified equipment and specifying the most effective track out 
prevention measures. The District concludes that an increase in the 
required frequency of street sweeping is not economically feasible at 
this time because most areas in the South Coast air basin already 
require regular street sweeping and a requirement to conduct more 
frequent street sweeping would achieve only minimal emission 
reductions.
    Based on our evaluation of the information provided in the 2016 
PM2.5 Plan, we agree with the SCAQMD's conclusion that Rule 
1186 implements RACM for the control of PM2.5 from paved and 
unpaved roads and livestock operations.
Commercial Charbroiling
    SCAQMD Rule 1138 (``Control of Emissions from Restaurant 
Operations''), adopted November 14, 1997, establishes control 
requirements to reduce PM and VOC emissions from chain-driven 
charbroilers at commercial cooking operations. The rule does not apply 
to under-fired charbroilers (UFCs). The EPA approved Rule 1138 into the 
California SIP on July 11, 2001.\104\
---------------------------------------------------------------------------

    \104\ 66 FR 36170.

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[[Page 40038]]

    Under Rule 1138, chain-driven charbroilers that cook 875 pounds of 
meat or more per week are required to be equipped and operated with a 
catalytic oxidizer control device, and the combination charbroiler/
catalyst must be tested and certified by the Executive Officer to 
reduce PM and VOC emissions. The District compared the requirements of 
Rule 1138 to several rules implemented in other parts of California and 
in other states that are designed to limit PM and/or VOC emissions from 
commercial charbroilers. Based on its review of analogous regulations 
implemented in these other areas, the District concludes that Rule 1138 
is generally equivalent to those regulations.
    Several times over the past 20 years and most recently in 2009, the 
District considered amending Rule 1138 to regulate PM emissions from 
UFCs, but to date the District has not identified control measures for 
UFCs that are both technologically and economically feasible for 
implementation in the South Coast. Although the Bay Area Air Quality 
Management District (BAAQMD) and New York City Department of 
Environmental Protection (NYDEP) have adopted rules that require 
controls for UFCs, neither agency has yet confirmed that any regulated 
sources that are subject to its rules have successfully installed and 
operated certified UFC control technologies.\105\ Staff at the BAAQMD 
recently noted that electrostatic precipitators have been installed in 
commercial kitchens in San Francisco and San Jose but that the BAAQMD 
has not yet enforced control requirements for UFCs because no control 
technologies have yet been certified.\106\ The 2016 PM2.5 
Plan contains a commitment by the District to adopt a control measure 
that requires controls on UFCs by 2025.\107\ The proposed measure is 
identified in the Plan as BCM-01.\108\
---------------------------------------------------------------------------

    \105\ Email dated July 11, 2019, from Stanley Tong, EPA Region 
IX, to Krishnan Balakrishnan, BAAQMD, Subject: ``Underfired 
charbroiler updates'' and email dated June 17, 2019, from Ronald 
Vaughn, NYDEP, to Stanley Tong, EPA Region IX, Subject: ``RE New 
Charbroiler Registrations NYC.'' See also 2016 PM2.5 
Plan, IV-A-186 to IV-A-190.
    \106\ Email dated January 9, 2020, from Virginia Lau, BAAQMD, to 
Stanley Tong, EPA Region IX, Subject: ``RE: Underfired charbroiler--
Q: SJ discussion about BA rule.''
    \107\ SCAQMD, Governing Board Resolution No. 17-2 (March 3, 
2017), 9 and 2016 PM2.5 Plan, Table 4-7.
    \108\ 2016 PM2.5 Plan, Table 4-7 and IV-A-186 to IV-
A-192 (describing BCM-01).
---------------------------------------------------------------------------

    Based on our evaluation of the information provided in the 2016 
PM2.5 Plan and additional information obtained during our 
review of the Plan, we agree with the SCAQMD's conclusion that Rule 
1138 implements RACM for the control of PM2.5 from 
commercial charbroilers.
Boilers, Steam Generators, and Process Heaters
    SCAQMD Rule 1146 (``Emissions of NOX from Industrial, 
Institutional, and Commercial Boilers, Steam Generators, and Process 
Heaters''), Rule 1146.1 (``Emissions of NOX from Small 
Industrial, Institutional, and Commercial Boilers, Steam Generators, 
and Process Heaters''), and Rule 1146.2 (``Emissions of NOX 
from Large Water Heaters and Small Boilers and Process Heaters) 
establish NOX emission limits for boilers, steam generators, 
and process heaters. The EPA approved Rule 1146 and Rule 1146.1, as 
amended November 1, 2013, into the California SIP on September 25, 
2014,\109\ and approved Rule 1146.2, as amended May 5, 2006, into the 
California SIP on December 5, 2008.\110\
---------------------------------------------------------------------------

    \109\ 79 FR 57442.
    \110\ 73 FR 74027.
---------------------------------------------------------------------------

    Rule 1146 applies to boilers, steam generators, and process heating 
units with ratings of more than 5 million British thermal units per 
hour (mmbtu/hr); Rule 1146.1 applies to units with ratings ranging from 
2 to 5 mmbtu/hr; and Rule 1146.2 applies to units with ratings less 
than 2 mmbtu/hr. Each rule sets NOX emission limits for 
different fuel types (e.g., digester gas, landfill gas, refinery gas). 
Rule 1146 and Rule 1146.1 also establish CO emission limits.
    The District compared the requirements of the SIP-approved versions 
of Rule 1146, Rule 1146.1, and Rule 1146.2 to several rules implemented 
elsewhere in California (i.e., Sacramento, the San Joaquin Valley, and 
the San Francisco Bay Area) that limit NOX and/or CO 
emissions from boilers, steam generators, process heaters and found 
that the SCAQMD rules are generally as stringent as or more stringent 
than other California air district rules for this source category. As 
part of the EPA's rulemakings to approve these rules into the SIP, the 
EPA concluded that the rules meet CAA requirements for enforceability, 
RACT, and SIP revisions.\111\
---------------------------------------------------------------------------

    \111\ 79 FR 57442 (September 25, 2014) and 73 FR 74027 (December 
5, 2008).
---------------------------------------------------------------------------

    SCAQMD amended Rule 1146, Rule 1146.1, and Rule 1146.2 on December 
7, 2018, to initiate the transition of the NOX RECLAIM 
program to a command-and-control regulatory structure. Although these 
amended rules have not yet been approved into the California SIP, the 
rule amendments are estimated to achieve an additional 0.27 tpd of 
NOX emission reductions by January 1, 2023.\112\
---------------------------------------------------------------------------

    \112\ SCAQMD Final Staff Report, ``Proposed Amended Rule 1146--
Emissions of Oxides of Nitrogen from Industrial, Institutional, and 
Commercial Boilers, Steam Generators, and Process Heaters; Proposed 
Amended Rule 1146.1--Emissions of Oxides of Nitrogen from Small 
Industrial, Institutional, and Commercial Boilers, Steam Generators, 
and Process Heaters; Proposed Amended Rule 1146.2--Emissions of 
Oxides of Nitrogen from Large Water Heaters and Small Boilers and 
Process Heaters; and Proposed Rule 1100--Implementation Schedule for 
NOx Facilities,'' December 2018, EX-2, available at http://www.aqmd.gov/docs/default-source/Agendas/Governing-Board/2018/2018-dec7-028.pdf?sfvrsn=6.
---------------------------------------------------------------------------

    Based on our evaluation of the information provided in the 2016 
PM2.5 Plan and additional information obtained during our 
review of the Plan, we agree with the SCAQMD's conclusion that Rule 
1146, Rule 1146.1, and Rule 1146.2 implement RACM for the control of 
NOX from boilers, steam generators, and process heaters.
iii. State Measures for Mobile Sources
    CARB's RACM analysis is contained in Attachment VI-A-3 
(``California Mobile Source Control Program Best Available Control 
Measures/Reasonably Available Control Measures Assessment'') (``BACM/
RACM assessment'') to Appendix VI-A of the 2016 PM2.5 Plan.
    CARB's BACM/RACM assessment provides a general description of 
CARB's existing mobile source programs. A more detailed description of 
CARB's mobile source control program, including a comprehensive table 
listing on- and off-road mobile source regulatory actions taken by CARB 
since 1985, is contained in Attachment VI-C-1 to Appendix VI-C of the 
2016 PM2.5 Plan. The BACM/RACM assessment contains CARB's 
evaluation of mobile source and other statewide control measures that 
reduce emissions of PM2.5 and PM2.5 precursors in 
California, including the South Coast air basin.
    Mobile source categories for which CARB has primary responsibility 
for reducing emissions in California include most new and existing on- 
and off-road engines and vehicles and motor vehicle fuels. Given the 
need for significant emission reductions from mobile sources to meet 
the NAAQS in California nonattainment areas, CARB has established 
stringent control measures for on-road and off-road mobile sources and 
the fuels that power them.\113\ California has unique authority

[[Page 40039]]

under CAA section 209 (subject to a waiver by the EPA) to adopt and 
implement new emission standards for many categories of on-road 
vehicles and engines, and new and in-use off-road vehicles and engines. 
The EPA has approved such mobile source regulations for which waiver 
authorizations have been issued as revisions to the California 
SIP.\114\
---------------------------------------------------------------------------

    \113\ California regulations use the term ``off-road'' to refer 
to ``nonroad'' vehicles and engines.
    \114\ See, e.g., 81 FR 39424 (June 16, 2016), 82 FR 14446 (March 
21, 2017), and 83 FR 23232 (May 18, 2018).
---------------------------------------------------------------------------

    CARB's mobile source program extends beyond regulations that are 
subject to the waiver or authorization process set forth in CAA section 
209 to 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.\115\
---------------------------------------------------------------------------

    \115\ See, e.g., the EPA's approval of standards and other 
requirements to control emissions from in-use heavy-duty diesel-
powered trucks at 77 FR 20308 (April 4, 2012), revisions to the 
California on-road reformulated gasoline and diesel fuel regulations 
at 75 FR 26653 (May 12, 2010), and revisions to the California motor 
vehicle I/M program at 75 FR 38023 (July 1, 2010).
---------------------------------------------------------------------------

iv. Local Jurisdiction Transportation Control Measures
    Transportation control measures (TCMs) are, in general, measures 
designed to reduce emissions from on-road motor vehicles through 
reductions in vehicle miles traveled (VMT) or traffic congestion. TCMs 
can reduce PM2.5 emissions in both the on-road motor vehicle 
exhaust and paved road dust source categories by reducing VMT and 
vehicle trips. They can also reduce vehicle exhaust emissions by 
relieving congestion. EPA guidance states that where mobile sources 
contribute significantly to PM2.5 violations, ``the state 
must, at a minimum, address the transportation control measures listed 
in CAA section 108(f) to determine whether such measures are achievable 
in the area considering energy, environmental, and economic impacts and 
other costs.'' \116\
---------------------------------------------------------------------------

    \116\ Addendum to General Preamble for the Implementation of 
Title I of the Clean Air Act Amendments of 1990,'' 59 FR 41998 
(August 16, 1994) (hereafter ``Addendum''), 42013.
---------------------------------------------------------------------------

    Appendix IV-C, ``Regional Transportation Strategy and Control 
Measures,'' contains SCAG's RACM analysis for TCMs. Consistent with EPA 
guidance, SCAG addressed the TCMs listed in CAA section 108(f) 
following a four-step process: (1) SCAG described the process by which 
they and the applicable transportation agencies in the South Coast air 
basin identify, review, and make enforceable commitments to implement 
TCMs; (2) SCAG assembled and reviewed control measures implemented in 
other ozone nonattainment areas (both in California and in other 
states); (3) SCAG compared candidate measures with measures implemented 
in the South Coast air basin to date, as well as new TCMs in the 
current Plan; and (4) SCAG provided reasoned justification for any 
available measures that have yet to be implemented. Based on their 
review, SCAG determined that the TCMs currently being implemented in 
the South Coast air basin include all RACM and that none of the 
identified candidate measures are both technically and economically 
feasible and would advance the attainment date in the South Coast. 
Attachment B of Appendix IV-C of the Plan contains a complete listing 
of all candidate measures evaluated as potential RACM, including a 
description of each measure, an indication of whether the measure is 
currently being implemented in the SCAG region, and a reasoned 
justification for SCAG's rejection of any measures that it has not 
adopted.
b. Additional Reasonable Measures
    As discussed above, the PM2.5 SIP Requirements Rule 
defines control measures that otherwise meet the definition of RACM but 
can only be implemented during the period beginning four years after 
the effective date of designation but before the Moderate area 
attainment date as ``additional reasonable measures.'' \117\
---------------------------------------------------------------------------

    \117\ 40 CFR 51.1000, 51.1009(a)(4)(i)(B), and 
51.1009(a)(4)(ii)(B).
---------------------------------------------------------------------------

    The 2016 PM2.5 Plan identifies four cost effective and 
technologically feasible control measures to be implemented in the year 
2020.\118\ These measures are BCM-04, BCM-10, CMB-03, and CMB-02. 
Because each of these measures is to be implemented in 2020, after the 
April 15, 2019 deadline for implementation of RACM/RACT but before the 
Moderate area attainment date of December 31, 2021, the District 
identifies these measures as ``additional reasonable measures'' for 
purposes of providing progress towards attainment of the 2012 
PM2.5 NAAQS.\119\ Details regarding the cost effectiveness 
analysis and the schedule for implementation of each of these four 
measures are provided in Chapter 4, Appendix IV-A, and Appendix IV-B of 
the 2016 PM2.5 Plan.
---------------------------------------------------------------------------

    \118\ 2016 PM2.5 Plan, Table 4-8.
    \119\ Id., Table VI-A-13.
---------------------------------------------------------------------------

c. Enforceable Commitments
    The 2016 PM2.5 Plan includes commitments by the District 
to adopt and implement certain measures and to achieve specific 
emission reductions in the South Coast area for purposes of attaining 
the 2012 PM2.5 NAAQS by 2025. Specifically, the SCAQMD has 
committed to (1) adopt, submit, and implement the control measures 
listed in Table 4-7 of the Plan by specified dates to achieve the total 
tonnages of emission reductions identified in Table 4-8 of the Plan, or 
substitute other measures as necessary to achieve those emission 
reductions, and (2) achieve the total tonnages of reductions of each 
pollutant by the dates specified in Table 4-8 of the Plan.\120\ If the 
SCAQMD determines that a particular measure listed in Table 4-7 of the 
Plan is infeasible, in whole or in part, the SCAQMD's commitment is to 
substitute other measures that will achieve equivalent emission 
reductions in the same adoption or implementation timeframes.\121\ The 
2016 PM2.5 Plan relies on these emission reduction 
commitments (also referred to as ``aggregate tonnage commitments'') as 
part of the control strategy for meeting the 2022 RFP milestones in the 
Plan and attaining the 2012 PM2.5 NAAQS by the December 31, 
2025 Serious area attainment date.\122\
---------------------------------------------------------------------------

    \120\ SCAQMD Governing Board Resolution No. 17-2 (March 3, 
2017), 9. The District clarified its aggregate tonnage commitments 
for the 2022 RFP milestone year in its Control Strategy Updates, 
``Summary'' tab (``South Coast AQMD Reasonable Further Progress for 
2012 Annual PM2.5 Standard'').
    \121\ 2016 PM2.5 Plan, Chapter 4, 4-53 and 4-54.
    \122\ Id. at 4-53 to 4-54 and Table 4-8.
---------------------------------------------------------------------------

    The District expects to meet its emission reduction commitments by 
adopting new control measures and programs and by strengthening 
existing control measures, as identified in Table 4-7 and Table 4-8 of 
the Plan. These new or revised control measures include rules to 
regulate appliances in commercial and residential applications, 
livestock wastes, non-refinery flares, greenwaste composting, and 
restaurant burners and residential cooking.
3. The EPA's Evaluation and Proposed Action
a. RACM/RACT and Additional Reasonable Measures
    We have reviewed the District's determination in the 2016 
PM2.5 Plan that its stationary and area source control 
measures represent RACM for PM2.5 and PM2.5 
precursors. In our review, we also considered our previous evaluations 
of the District's rules in

[[Page 40040]]

connection with our approval of the SCAQMD's RACT SIP demonstration for 
the 2008 ozone NAAQS.\123\ Based on this review, we believe the 
District's rules provide for the implementation of RACM for stationary 
and area sources of PM2.5 and PM2.5 precursors.
---------------------------------------------------------------------------

    \123\ 82 FR 43850 (September 20, 2017).
---------------------------------------------------------------------------

    With respect to mobile sources, CARB's current program addresses 
the full range of mobile sources in the South Coast through regulatory 
programs for both new and in-use vehicles. With respect to 
transportation controls, we find that SCAG has a well-established TCM 
development program in which TCMs are continuously identified, 
reviewed, and evaluated throughout the transportation planning process. 
Overall, we believe that the programs developed and administered by 
CARB and SCAG provide for the implementation of RACM for 
PM2.5 and PM2.5 precursors in the South Coast 
nonattainment area.
    Finally, the 2016 PM2.5 Plan contains enforceable 
commitments to adopt and implement a number of additional reasonable 
measures by 2020, for purposes of meeting the 2022 RFP milestones in 
the Plan and attaining the 2012 PM2.5 NAAQS by the December 
31, 2025 Serious area attainment date.
    For all of these reasons, we propose to find that the 2016 
PM2.5 Plan provides for the implementation of RACM and 
additional reasonable measures for all sources of direct 
PM2.5 and PM2.5 precursors as expeditiously as 
practicable, for purposes of the 2012 PM2.5 NAAQS in the 
South Coast area, in accordance with the requirements of CAA section 
189(a)(1)(C) and 40 CFR 51.1009.
b. Enforceable Commitments
    In addition, we are proposing to approve the District's enforceable 
commitments to adopt and implement certain measures by specific dates 
and to achieve specific tonnages of emission reductions from these or 
appropriate substitute measures, by 2022, as part of the control 
strategy and RFP demonstration in the 2016 PM2.5 Plan. These 
commitments to adopt and implement control measures and to achieve 
emission reductions, in the aggregate, by specified dates satisfy the 
EPA's 3-factor test for approval of such enforceable commitments.
    The 2016 PM2.5 Plan provides for the majority of the 
emission reductions necessary for making progress towards attainment to 
be achieved from baseline measures. These reductions come from a 
combination of District, State, and federal stationary and mobile 
source measures.\124\ Over the past four decades, the District has 
adopted or revised almost 100 prohibitory rules that limit emissions of 
direct PM, NOX, SO2, VOC, and ammonia from 
stationary sources. The vast majority of these rules are currently SIP-
approved and as such, their emission reductions are fully creditable in 
attainment-related SIPs. California has also adopted standards for many 
categories of on- and off-road vehicles and engines as well as 
standards for gasoline and diesel fuels. The State's mobile source 
measures are discussed in Section V.D.2.a.iii of this proposed rule. 
The remaining reductions needed for attainment are to be achieved 
through the District's enforceable commitments to achieve emission 
reductions in the South Coast through the anticipated defined control 
measures listed in Table 4-7 and Table 4-8 of the Plan.
---------------------------------------------------------------------------

    \124\ Federal measures include the EPA's national emission 
standards for heavy duty diesel trucks (66 FR 5001 (January 18, 
2001)), certain new construction and farm equipment (Tier 2 and 3 
non-road engines standards (63 FR 56968 (October 23, 1998), and Tier 
4 diesel non-road engine standards (69 FR 38958 (June 29, 2004)), 
and locomotives (63 FR 18978 (April 16, 1998) and 73 FR 37096 (June 
30, 2008)). States are allowed to rely on reductions from federal 
measures in attainment and RFP demonstrations and for other SIP 
purposes.
---------------------------------------------------------------------------

    With respect to the 2016 PM2.5 Plan, circumstances 
warrant the consideration of enforceable commitments as part of the 
control strategy and RFP demonstration for the South Coast 
nonattainment area. As discussed below, a majority of the emission 
reductions that are needed to demonstrate RFP in the South Coast 
nonattainment area come from rules and regulations that were adopted 
prior the submittal of the Plan in April 2017 (i.e., baseline 
measures). As a result of these already-adopted State and District 
measures, most sources in the South Coast nonattainment area were 
already subject to stringent rules prior to the development of the 
Plan, leaving fewer and more technologically challenging opportunities 
to reduce emissions. In the 2016 PM2.5 Plan, the District 
identified potential control measures that could achieve the additional 
emission reductions needed to demonstrate RFP toward attainment by the 
Serious area attainment date. However, the timeline needed to develop, 
adopt, and implement these measures went beyond the October 15, 2016 
statutory deadline for submitting the Plan. The District has made 
progress in adopting measures to meet its commitments but has not yet 
completely fulfilled them. Given these circumstances, the 2016 
PM2.5 Plan's reliance on enforceable commitments is 
warranted. We now consider the three factors the EPA uses to determine 
whether the use of enforceable commitments in lieu of adopted measures 
satisfies CAA planning requirements.
i. Commitments Are a Limited Portion of Required Reductions
    For the first factor, we look to see if the commitment addresses a 
limited portion of a statutory requirement, such as the amount of 
emission reductions needed to demonstrate RFP in a nonattainment area. 
As discussed in greater detail in section V.G, the Plan demonstrates 
RFP for the 2019 RFP milestone year and 2022 post-attainment milestone 
year for purposes of the 2012 PM2.5 Moderate area plan. For 
the 2019 milestone year, the plan demonstrates that RFP is achieved by 
emission reductions from baseline measures alone, whereas the RFP 
demonstration for the 2022 milestone year relies on emission reductions 
from new control measures committed to in the 2016 PM2.5 
Plan.\125\ As shown in Table 3, of the emission reductions needed to 
meet the 2022 RFP milestone for the 2012 PM2.5 NAAQS in the 
South Coast nonattainment area, 7 tpd of NOX emission 
reductions need to be achieved by new or revised control strategy 
measures --that is, State and District baseline measures achieve all 
but 7 tpd of the NOX emission reductions necessary to meet 
the RFP milestone for 2022. This represents approximately 3 percent of 
the NOX reductions needed to meet the 2022 RFP milestone. 
Historically, the EPA has approved SIPs with enforceable commitments in 
the range of approximately 10 to 13 percent of the total reductions 
needed for attainment.\126\ We find that the District's NOX 
commitment addresses a limited proportion of the required emission 
reductions.
---------------------------------------------------------------------------

    \125\ 2016 PM2.5 Plan, Table VI-C-5A.
    \126\ See, e.g., our approvals of the SJV PM10 plan 
at 69 FR 30005 (May 26, 2004), the SJV 1-hour ozone plan at 75 FR 
10420 (March 8, 2010), the Houston-Galveston 1-hour ozone plan at 66 
FR 57160 (November 14, 2001), the SJV PM2.5 plan at 76 FR 
69896 (November 9, 2011), and the South Coast PM2.5 plan 
at 76 FR 69928 (November 9, 2011).

[[Page 40041]]

          Table 3--Reductions Needed for RFP Remaining as Commitments Based on SIP-Creditable Measures
----------------------------------------------------------------------------------------------------------------
                                       PM2.5            NOX             SOX             VOC           Ammonia
----------------------------------------------------------------------------------------------------------------
A. 2012 baseline emissions level            66.4             540            18.4             470            81.1
B. 2022 RFP target level........            64.6             283            17.6             367            74.4
C. Total reductions needed from              1.8             257             0.8             103             6.7
 2012 baseline levels to
 demonstrate RFP (A-B)..........
D. 2022 RFP baseline emissions                64             290              17             362              73
 level..........................
E. Reductions from baseline                  2.4             250             1.4             108             8.1
 measures (A-D).................
F. Reductions needed from new/                 0               7               0               0               0
 revised control strategy
 measures (D-B).................
G. Percent of reductions needed                0            2.7%               0               0               0
 to meet RFP from new control
 measures (F/C).................
----------------------------------------------------------------------------------------------------------------
Data Source: 2016 PM2.5 Plan, Table 3-4B and Table VI-C-5A.

ii. The State Is Capable of Fulfilling Its Commitment
    For the second factor, we consider whether the District is capable 
of fulfilling its commitments.
    The District has made significant progress in meeting its 
enforceable commitments for the 2022 post-attainment RFP milestone 
year. It has adopted numerous baseline measures that are projected to 
achieve additional reductions of NOX in future years as 
shown in Table 4. In addition to the measures discussed above, both 
CARB and the District have well-funded incentive grant programs to 
reduce emissions from the on- and off-road engine fleets. Reductions 
from these programs have yet to be quantified and/or credited in the 
RFP demonstration.

               Table 4--SCAQMD Control Measure Updates Since the 2016 Air Quality Management Plan
----------------------------------------------------------------------------------------------------------------
                                                                                              NOX         VOC
         Control measure                Rule         Adoption    Final  implementation     reduction   reduction
                                                       date             date(s)              (tpd)       (tpd)
----------------------------------------------------------------------------------------------------------------
CMB-02..........................  Rule 1111--          * 3/2/  1/1/2046.................       0.017  ..........
                                   ``Natural-Gas-        2018
                                   Fired, Fan-Type
                                   Central
                                   Furnaces''.
CTS-01 (2012 AQMP)..............  Rule 1113--        2/5/2016  1/1/2019.................  ..........        0.88
                                   ``Architectural
                                   Coatings''.
CMB-03..........................  Rule 1118.1--      1/4/2019  7/1/2024.................         0.2  ..........
                                   ``Non-Refinery
                                   Flares''.
CMB-01, CMB-05..................  Rule 1134--        4/5/2019  12/31/2023...............         2.8  ..........
                                   ``Stationary
                                   Gas Turbines''.
CMB-01, CMB-05..................  Rule 1135--       11/2/2018  1/1/2024.................         1.8       0.014
                                   ``Electricity
                                   Generating
                                   Facilities''.
CMB-01, CMB-05..................  Rule 1146, Rule   12/7/2018  1/1/2023.................        0.27  ..........
                                   1146.1, Rule
                                   1146.2--``Non-
                                   Refinery
                                   Boilers and
                                   Heaters''.
CTS-01..........................  Rule 1168--       10/6/2017  2017, 2019, 2023.........  ..........         1.4
                                   ``Adhesive and
                                   Sealant
                                   Applications''.
----------------------------------------------------------------------------------------------------------------
Source: Email dated September 12, 2019 from Kalam Cheung, SCAQMD, to Ashley Graham, EPA Region IX, attaching
  spreadsheet entitled ``Draft Rule Adoption since 2016 AQMP 20190809.xlsx.''
* SCAQMD further amended Rule 1111 on July 6, 2018 and December 6, 2019.

    Given the District's efforts to date and its continuing efforts to 
reduce emissions, we believe it is capable of meeting its enforceable 
commitments to achieve the reductions needed to meet its 2022 RFP 
milestones for the 2012 PM2.5 NAAQS.
iii. The Commitment Is for a Reasonable and Appropriate Timeframe
    For the third and last factor, we consider whether the commitment 
is for a reasonable and appropriate period of time.
    In order to meet the commitments to adopt measures and reduce 
emissions to the levels needed to meet the area's 2022 RFP milestones 
for the 2012 PM2.5 NAAQS in the South Coast nonattainment 
area, the 2016 PM2.5 Plan includes ambitious rule 
development, adoption, and implementation schedules for a number of 
defined control measures. The District has committed to achieve 20.5 
tpd of NOX emission reductions by 2022 through adoption and 
implementation of these defined measures or substitute measures that 
achieve equivalent emission reductions. We believe that these 
timeframes are appropriate given the technological and economic 
challenges associated with the control measures that will be needed to 
achieve these reductions and the State's and District's required 
procedures for development and adoption of these measures. In addition, 
these reductions are not needed to meet the earlier 2019 RFP 
milestones. Thus, the commitment is for a reasonable and appropriate 
period of time.
    Based on our consideration of these three factors, we are proposing 
to approve the District's commitments to adopt and implement specific 
control measures on the schedule identified in Table 4-7 and Table 4-8 
of the 2016 PM2.5 Plan to the extent that these commitments 
have not yet been fulfilled, and to achieve specific emission 
reductions by 2022, as given in these tables and in the Control 
Strategy Updates.

E. Major Stationary Source Control Requirements Under CAA Section 
189(e)

    CAA section 189(e) specifically requires that the control 
requirements applicable to major stationary sources of direct 
PM2.5 also apply to major stationary sources of 
PM2.5 precursors, except where the Administrator determines 
that such sources do not contribute significantly to PM2.5 
levels that exceed the standards in the area.\127\ The control 
requirements applicable to major stationary sources of direct 
PM2.5 in a Moderate PM2.5 nonattainment area 
include, at a minimum, the requirements of a NNSR permit program 
meeting the requirements of CAA sections 172(c)(5) and 189(a)(1)(A). In 
the PM2.5 SIP Requirements Rule, we established a deadline 
for states to

[[Page 40042]]

submit NNSR plan revisions to implement the PM2.5 NAAQS 18 
months after an area is initially designated and classified as a 
Moderate nonattainment area.\128\
---------------------------------------------------------------------------

    \127\ General Preamble, 13539 and 13541-13542.
    \128\ 81 FR 58010, 58115.
---------------------------------------------------------------------------

    California submitted NNSR SIP revisions for the South Coast to 
address the subpart 4 requirements for Moderate PM2.5 
nonattainment areas on December 29, 2014.\129\ The EPA fully approved 
these SIP revisions on May 1, 2015.\130\ California also submitted NNSR 
SIP revisions for the South Coast to address the subpart 4 requirements 
for Serious PM2.5 nonattainment areas on May 8, 2017, and 
the EPA conditionally approved these SIP revisions on November 30, 
2018.\131\ The basis for the November 30, 2018 conditional approval was 
a commitment by CARB and the SCAQMD to submit a revised version of Rule 
1325 by December 30, 2019. CARB submitted a revised version of Rule 
1325 to the EPA on April 24, 2019, fulfilling this commitment.\132\ 
Accordingly, in this action, the EPA is not addressing the NNSR control 
requirements that apply to major stationary sources of direct 
PM2.5 and PM2.5 precursors in the South Coast 
area under CAA section 189(e).
---------------------------------------------------------------------------

    \129\ Letter dated December 29, 2014, from Richard W. Corey, 
Executive Officer, CARB, to Jared Blumenfeld, Regional 
Administrator, EPA Region 9.
    \130\ 80 FR 24821.
    \131\ 83 FR 61551.
    \132\ Letter dated April 24, 2019, from Richard W. Corey, 
Executive Officer, CARB, to Mike Stoker, Regional Administrator, EPA 
Region 9.
---------------------------------------------------------------------------

F. Demonstration That Attainment by the Moderate Area Attainment Date 
Is Impracticable

1. Requirements for Attainment/Impracticability of Attainment 
Demonstrations
    CAA section 189(a)(1)(B) requires that each Moderate area 
attainment plan include a demonstration that the plan provides for 
attainment by the applicable Moderate area attainment date or, 
alternatively, that attainment by such date is impracticable. This 
provision explicitly requires that a demonstration of attainment be 
based on air quality modeling but does not require such modeling for an 
impracticability demonstration. Although the EPA expects that most 
impracticability demonstrations will also be supported by air quality 
modeling, it may be possible in some cases to support an 
impracticability demonstration with ambient PM2.5 data and 
other relevant non-modeling information.\133\
---------------------------------------------------------------------------

    \133\ 81 FR 58010, 58048 and 58049.
---------------------------------------------------------------------------

    CAA section 188(c) states, in relevant part, that the Moderate area 
attainment date ``shall be as expeditiously as practicable but no later 
than the end of the sixth calendar year after the area's designation as 
nonattainment . . .'' For the South Coast area, which was initially 
designated as nonattainment for the 2012 PM2.5 standard 
effective April 15, 2015, the applicable Moderate area attainment date 
under section 188(c) for this standard is as expeditiously as 
practicable but no later than December 31, 2021.
    In SIP submissions that demonstrate impracticability, the state 
should document how its required control strategy in the attainment 
plan represents the application of RACM/RACT and additional reasonable 
measures, at minimum, to existing sources. The EPA believes it is 
appropriate to require adoption of all available control measures that 
are reasonable, i.e., technologically and economically feasible, in 
areas that do not demonstrate timely attainment, even where those 
measures cannot be implemented within the 4-year timeframe for 
implementation of RACM/RACT under CAA section 189(a)(1)(C). The 
impracticability demonstration will then be based on a showing that the 
area cannot attain by the applicable attainment date, notwithstanding 
implementation of the required controls.
2. Impracticability Demonstration in the 2016 PM2.5 Plan
    The 2016 PM2.5 Plan includes a demonstration, based on 
air quality modeling, that even with the implementation of RACM/RACT 
and additional reasonable measures for all appropriate sources, 
attainment by December 31, 2021 is not practicable. The 
impracticability demonstration is included in Appendix VI-B of the 2016 
PM2.5 Plan.
    Modeled annual average PM2.5 concentrations are 
presented for five monitoring sites representing high PM2.5 
concentrations in the South Coast air basin. Annual PM2.5 
concentrations were modeled for the 2012 base year and 2021 attainment 
year. For 2021, the District examined both baseline and control 
scenarios. The demonstration is summarized in Table 5.

               Table 5--Impracticability Demonstration--Annual Average PM2.5 Design Concentrations
                                                 [[micro]g/m\3\]
----------------------------------------------------------------------------------------------------------------
                                                                                                       2021
                             Station                                   2012       2021  Baseline    Controlled
----------------------------------------------------------------------------------------------------------------
Los Angeles.....................................................            12.4            10.9            10.6
Anaheim.........................................................            10.6             9.4             9.1
Rubidoux........................................................            13.2            11.2            10.9
Mira Loma.......................................................            14.9            12.6            12.3
Fontana.........................................................            12.6            10.6            10.4
----------------------------------------------------------------------------------------------------------------
Source: 2016 PM2.5 Plan, Table VI-B-2.

3. The EPA's Evaluation and Proposed Action
    The impracticability demonstration in the 2016 PM2.5 
Plan is based on air quality modeling that is generally consistent with 
applicable EPA guidance. We find the modeling adequate to support the 
impracticability demonstration in the plan. See section V.C of this 
notice.
    We have also evaluated the RACM/RACT and additional reasonable 
measures demonstration and find that it provides for the expeditious 
implementation of all RACM/RACT and additional reasonable measures that 
may feasibly be implemented at this time, consistent with the 
requirements of CAA sections 172(c)(1) and 189(a)(1)(C) for the 2012 
PM2.5 NAAQS in the South Coast. See section V.D of this 
notice.
    Finally, we have evaluated the demonstration in the 2016 
PM2.5 Plan that the implementation of the State/District's 
SIP control strategy, including

[[Page 40043]]

RACM/RACT and additional reasonable measures, is insufficient to bring 
the South Coast into attainment by December 31, 2021. In addition to 
the information in the 2016 PM2.5 Plan, we have reviewed 
recent PM2.5 monitoring data from the South Coast. These 
data show that annual PM2.5 levels in the South Coast, with 
a current design value (2016-2018) of 14.7 [micro]g/m\3\, continue to 
be well above the 12.0 [micro]g/m\3\ level of the 2012 PM2.5 
standard, and the recent trends in annual PM2.5 levels in 
the South Coast are not consistent with a projection of attainment by 
the end of 2021.\134\
---------------------------------------------------------------------------

    \134\ EPA, Design Value Spreadsheets, 
``20200306_SouthCoastPM25Annual.xlsx'' and 
``pm25_designvalues_20162018_final_12_03_19.xlsx.''
---------------------------------------------------------------------------

    Based on this evaluation, we propose to approve the State's 
demonstration in the 2016 PM2.5 Plan that attainment of the 
2012 PM2.5 NAAQS in the South Coast by the Moderate area 
attainment date of December 31, 2021, is impracticable, consistent with 
the requirements of CAA section 189(a)(1)(B)(ii). On this basis, we 
also propose to reclassify the South Coast as a Serious nonattainment 
area, which would trigger requirements for the State to submit a 
Serious area plan consistent with the requirements of subparts 1 and 4 
of part D, title I of the Act (see section VI of this notice).

G. Reasonable Further Progress and Quantitative Milestones

1. Requirements for Reasonable Further Progress and Quantitative 
Milestones
    CAA section 172(c)(2) states that all nonattainment area plans 
shall require RFP. In addition, CAA section 189(c) requires that all 
PM2.5 nonattainment area SIPs include quantitative 
milestones to be achieved every three years until the area is 
redesignated to attainment and which demonstrate RFP. Section 171(1) 
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 a set percentage 
of emission reductions be achieved in any given year for purposes of 
satisfying the RFP requirement.
    For purposes of the PM2.5 NAAQS, the EPA has interpreted 
the RFP requirement to require that nonattainment area plans show 
annual incremental emission reductions sufficient to maintain generally 
linear progress toward attainment by the applicable deadline.\135\ As 
discussed in EPA guidance in the Addendum to the General Preamble 
(``Addendum''),\136\ requiring linear progress in reductions of direct 
PM2.5 and any individual precursor in a PM2.5 
plan may be appropriate in situations where:
---------------------------------------------------------------------------

    \135\ Addendum to the General Preamble, 59 FR 41998, 42015 
(August 16, 1994).
    \136\ Id.
---------------------------------------------------------------------------

     The pollutant is emitted by a large number and range of 
sources,
     the relationship between any individual source or source 
category and overall air quality is not well known,
     a chemical transformation is involved (e.g., secondary 
particulate significantly contributes to PM2.5 levels over 
the standard), and/or
     the emission reductions necessary to attain the 
PM2.5 standard are inventory-wide.\137\
---------------------------------------------------------------------------

    \137\ Id.
---------------------------------------------------------------------------

    The Addendum indicates that requiring linear progress may be less 
appropriate in other situations, such as:
     Where there are a limited number of sources of direct 
PM2.5 or a precursor,
     where the relationships between individual sources and air 
quality are relatively well defined, and/or
     where the emission control systems utilized (e.g., at 
major point sources) will result in a swift and dramatic emission 
reductions.
    In nonattainment areas characterized by any of these latter 
conditions, RFP may be better represented as step-wise progress as 
controls are implemented and achieve significant reductions soon 
thereafter. For example, if an area's nonattainment problem can be 
attributed to a few major sources, EPA guidance indicates that ``RFP 
should be met by `adherence to an ambitious compliance schedule' which 
is likely to periodically yield significant emission reductions of 
direct PM2.5 or a PM2.5 precursor.'' \138\
---------------------------------------------------------------------------

    \138\ Id.
---------------------------------------------------------------------------

    Attainment plans for PM2.5 nonattainment areas should 
include detailed schedules for compliance with emission regulations in 
the area and provide corresponding annual emission reductions to be 
achieved by each milestone in the schedule.\139\ In reviewing an 
attainment plan under subpart 4, the EPA considers whether the annual 
incremental emission reductions to be achieved are reasonable in light 
of the statutory objective of timely attainment. Although early 
implementation of the most cost-effective control measures is often 
appropriate, states should consider both cost-effectiveness and 
pollution reduction effectiveness when developing implementation 
schedules for control measures and may implement measures that are more 
effective at reducing PM2.5 earlier, to provide greater 
public health benefits.\140\
---------------------------------------------------------------------------

    \139\ Id. at 42016.
    \140\ Id.
---------------------------------------------------------------------------

    The PM2.5 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 PM2.5 SIP Requirements Rule, each 
PM2.5 attainment plan must contain an RFP analysis that 
includes, at a minimum, the following four components: (1) An 
implementation schedule for control measures; (2) RFP projected 
emissions for direct PM2.5 and all PM2.5 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.\141\ States should estimate the RFP projected 
emissions for each quantitative milestone year by sector on a 
pollutant-by-pollutant basis.\142\ In an area that cannot practicably 
attain the PM2.5 standard by the applicable Moderate area 
attainment date, full implementation of a control strategy that 
satisfies the Moderate area control requirements represents RFP towards 
attainment.\143\
---------------------------------------------------------------------------

    \141\ 40 CFR 51.1012(a).
    \142\ 81 FR 58010, 58056.
    \143\ Id. at 58056, 58057.
---------------------------------------------------------------------------

    Section 189(c) requires that attainment plans include quantitative 
milestones that demonstrate RFP. The purpose of the quantitative 
milestones is to allow for periodic evaluation of the area's progress 
towards attainment of the NAAQS consistent with RFP requirements. 
Because RFP is an annual emission reduction requirement and the 
quantitative milestones are to be achieved every three years, when a 
state demonstrates compliance with the quantitative milestone 
requirement, it will demonstrate that RFP has been achieved during each 
of the relevant three years. Quantitative milestones

[[Page 40044]]

should provide an objective means to evaluate progress toward 
attainment meaningfully, e.g., through imposition of emission controls 
in the attainment plan and the requirement to quantify those required 
emission reductions. The CAA also requires states to submit milestone 
reports (due 90 days after each milestone), and these reports should 
include calculations and any assumptions made by the state concerning 
how RFP has been met, e.g., through quantification of emission 
reductions to date.\144\ The Act requires states to include RFP and 
quantitative milestones even for areas that cannot practicably attain.
---------------------------------------------------------------------------

    \144\ Addendum, 42016-42017.
---------------------------------------------------------------------------

    The CAA does not specify the starting point for counting the three-
year periods for quantitative milestones under CAA section 189(c). In 
the General Preamble and 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.\145\ Consistent with 
this longstanding interpretation of the Act, the PM2.5 SIP 
Requirements Rule requires that each plan for a Moderate 
PM2.5 nonattainment area contain quantitative milestones to 
be achieved no later than milestone dates 4.5 years and 7.5 years from 
the date of designation of the area.\146\ Because the EPA designated 
the South Coast area nonattainment for the 2012 PM2.5 NAAQS 
effective April 15, 2015,\147\ the applicable quantitative milestone 
dates for purposes of this NAAQS in the South Coast are October 15, 
2019 and October 15, 2022. Following reclassification of the South 
Coast area as Serious for the 2012 PM2.5 standard, later 
milestones would be addressed by the Serious area plan.\148\
---------------------------------------------------------------------------

    \145\ General Preamble, 13539, and Addendum, 42016.
    \146\ 40 CFR 51.1013(a)(1).
    \147\ 80 FR 2206.
    \148\ Addendum, 42016.
---------------------------------------------------------------------------

2. Reasonable Further Progress Demonstration and Quantitative 
Milestones in the 2016 PM2.5 Plan
    The RFP plan and quantitative milestones are discussed in section 
VI-C of Appendix VI of the 2016 PM2.5 Plan. The Plan 
estimates that emissions of direct PM2.5, NOX, 
SOX, VOC, and ammonia will generally decline from the 2012 
base year and states that emissions of each of these pollutants will 
remain below the levels needed to show ``generally linear progress'' 
through 2022, the Moderate area post-attainment milestone year for the 
2012 PM2.5 NAAQS.\149\ The Plan's emissions inventory shows 
that direct PM2.5, NOX, SOX, VOC, and 
ammonia are emitted by a large number and range of sources in the South 
Coast and that the emission reductions needed for each of these 
pollutants are inventory-wide.\150\ Table VI-C-4 of the 2016 
PM2.5 Plan contains an implementation schedule for adopted 
District control measures,\151\ Table VI-C-6 contains emission 
reduction commitments to be achieved each year from 2016 to 2025, and 
Table VI-C-5 (reproduced, in part,\152\ in Table 6) contains RFP 
projected emissions for each quantitative milestone year. Based on 
these analyses, the District concludes that its adopted control 
strategy will achieve, for each pollutant, projected emission levels at 
or below the RFP and quantitative milestone target emission levels for 
2019 and 2022 (see Table 7).\153\
---------------------------------------------------------------------------

    \149\ 2016 PM2.5 Plan, Table VI-C-5 and Table VI-C-
5A.
    \150\ Id., Chapter 4 and appendices IV-A, VI-B, and VI-C.
    \151\ See also email dated September 12, 2019 from Kalam Cheung, 
SCAQMD, to Ashley Graham, EPA Region IX, attaching spreadsheet 
entitled ``Draft Rule Adoption since 2016 AQMP 20190809.xlsx.''
    \152\ Table 6 identifies only emission levels for milestone 
years that must be addressed by the Moderate area plan.
    \153\ 2016 PM2.5 Plan, VI-C-9.

          Table 6--Annual PM2.5 Baseline Emissions for Base Year and Moderate Area Plan Milestone Years
                                              [Annual average tpd]
----------------------------------------------------------------------------------------------------------------
                                                                                       2019            2022
                            Pollutant                             2012  Baseline   (Quantitative   (Quantitative
                                                                                    milestone)      milestone)
----------------------------------------------------------------------------------------------------------------
PM2.5...........................................................            66.4            63.9            64.1
NOX.............................................................             540             353             275
SOX.............................................................            18.4            16.6            17.0
VOC.............................................................             470             376             348
Ammonia.........................................................            81.1            74.0            72.6
----------------------------------------------------------------------------------------------------------------
Source: 2016 PM2.5 Plan, Table VI-C-5.

                                Table 7--Summary of Annual PM2.5 RFP Calculations
----------------------------------------------------------------------------------------------------------------
         Row               Calculation step         PM2.5         NOX          SOX          VOC        Ammonia
----------------------------------------------------------------------------------------------------------------
1....................  2012 base year emissions         66.4          540         18.4          470         81.1
                        (tpd).
2....................  Annual percent change            0.27          4.8         0.43          2.2         0.83
                        needed to show linear
                        progress (%).
3....................  2019 target needed to            65.2          360         17.8          398         76.4
                        show linear progress
                        (tpd).
4....................  2019 baseline emissions          63.9          353         16.6          376         74.0
                        (tpd).
5....................  Projected shortfall                 0            0            0            0            0
                        (tpd).
6....................  Surplus in 2019 (tpd)...          1.3          6.8          1.2         22.2          2.4
7....................  2022 target needed to            64.6          283         17.6          367         74.4
                        show linear progress
                        (%).
8....................  2022 emissions (tpd) *..         64.1          275         17.0          348         72.6
9....................  Projected shortfall                 0            0            0            0            0
                        (tpd).
10...................  Surplus in 2022 (tpd)...         0.56          8.0         0.59         18.5          1.7
----------------------------------------------------------------------------------------------------------------
* Based on controlled emissions with emission reductions committed to in the 2016 PM2.5 Plan.
Source: 2016 PM2.5 Plan, Table VI-C-5A.

    The 2016 PM2.5 Plan documents the State's conclusion 
that all RACM/RACT and additional reasonable measures for these 
pollutants are being implemented as expeditiously as practicable and 
identifies projected levels of direct

[[Page 40045]]

PM2.5, NOX, SOX, VOC, and ammonia 
emissions that reflect full implementation of the State, District, and 
SCAG's RACM/RACT and additional reasonable measure control strategy for 
these pollutants.\154\ The control strategy that provides the basis for 
these emission projections is described in Chapter 4, Appendix IV, and 
Appendix VI of the 2016 PM2.5 Plan.
---------------------------------------------------------------------------

    \154\ Id. at VI-C-5 to VI-C-12; see also evaluation of RACM/RACT 
in section V.D of this proposed rule.
---------------------------------------------------------------------------

Direct PM2.5
    The District has several stationary and area source rules that are 
projected to contribute to RFP and attainment of the PM2.5 
standards.\155\ For example, Rule 444 (``Open Burning'') and Rule 445 
(``Residential Wood Burning Devices'') were amended in 2013 to achieve 
PM2.5 reductions during winter episodic conditions. The 2013 
amendments to Rule 445 lowered the mandatory winter burning curtailment 
program threshold for residential wood burning and, in certain cases, 
extended the curtailment to the entire South Coast air basin, thereby 
further limiting emissions from one of the largest direct 
PM2.5 combustion sources in the South Coast nonattainment 
area.\156\ These rule amendments provide part of the incremental 
reductions in emissions of direct PM2.5 needed from the 2012 
base year to meet RFP requirements.\157\ Measures to control sources of 
direct PM2.5 are also presented in the Plan's RACM analyses 
and are reflected in the Plan's baseline emission projections.
---------------------------------------------------------------------------

    \155\ Id., Table III-2-2B and Table 4-8.
    \156\ Id., Table III-1-2. See also 78 FR 59249 (September 26, 
2013).
    \157\ Id., Table VI-C-4.
---------------------------------------------------------------------------

    The Plan highlights on-road and other mobile source control 
measures as the primary means for achieving direct PM2.5 
emission reductions. CARB's implementation of the Truck and Bus 
Regulation achieved PM2.5 emission reductions beginning in 
2012.\158\ Lighter trucks and buses were required to replace 1995 and 
older engines with a 2010 model year by 2015. The 2010 model year 
engines include particulate filters. CARB's LEV II program includes PM 
emission limits by model year for 2016, and the LEV II program has 
stricter emission limits for 2017 and beyond. For off-road vehicles, 
CARB adopted the In-Use Off Road Diesel-Fueled Fleets Regulation 
(``Off-Road Regulation'') in 2007. The Off-Road Regulation requires 
owners to replace older vehicles or engines with newer, cleaner models 
to either (1) retire older vehicles or reduce their use, or (2) to 
apply retrofit exhaust controls. Off-road fleets are required to meet 
increasingly strict fleet average indices over time.\159\ These indices 
reflect a fleet's overall emission rates of PM and NOX for 
model year and horsepower combinations. Fleets were also banned from 
adding Tier 0 off-road engines as of January 1, 2014.\160\ CARB 
implemented a similar ban on Tier 1 engines between January 1, 2014 
(large fleets) and January 1, 2016 (small fleets).
---------------------------------------------------------------------------

    \158\ The State's quantitative milestone report for the 2017 
milestone for the 2006 PM2.5 standards indicates that the 
requirement for heavier trucks to install diesel particulate filters 
was fully implemented by 2016. See SCAQMD, ``2017 Quantitative 
Milestone Report for the 2006 24-hour PM2.5 National 
Ambient Air Quality Standard,'' March 2018 (``2017 QM Report''), 11.
    \159\ A fleet average index is an indicator of a fleet's overall 
emissions rate of PM and NOX based on the horsepower and 
model year of each engine in the fleet.
    \160\ Tier 0 engines meet 1995 to 1999 emission standards, 
depending on engine size and horsepower. See http://www.assocpower.com/eqdata/tech/US-EPA-Tier-Chart_1995-2004.php.
---------------------------------------------------------------------------

Nitrogen Oxides
    The District regulates numerous NOX emission sources 
such as residential space and water heating devices, stationary 
internal combustion engines, and various sizes of boilers, steam 
generators, and process heaters used in industrial settings. The 2016 
PM2.5 Plan identifies the following South Coast regulations 
as measures that achieve ongoing NOX reductions with 
compliance dates during the RFP years of the Plan: Rule 1111 
(``Reductions of NOX from Natural Gas-Fired, Fan-Type 
Central Furnaces''), Rule 1146.2 (``Emission of Oxides of Nitrogen from 
Large Water Heaters and Small Boilers and Process Heaters''), and Rule 
1147 (``NOX Reductions from Miscellaneous 
Sources'').161 162
---------------------------------------------------------------------------

    \161\ 2016 PM2.5 Plan, Table VI-C-4. See also email 
dated September 12, 2019 from Kalam Cheung, SCAQMD, to Ashley 
Graham, EPA Region IX, attaching spreadsheet entitled ``Draft Rule 
Adoption since 2016 AQMP 20190809.xlsx.''
    \162\ Rule 1111 was mistakenly listed as Rule 1110 in the 2016 
PM2.5 Plan, Table VI-C-4. See 2017 QM Report, 6, footnote 
1.
---------------------------------------------------------------------------

    In addition to these baseline measures, the District has committed 
to adopt and implement several new measures to reduce NOX 
emissions and ensure RFP toward attainment of the 2012 PM2.5 
NAAQS in the South Coast air basin. These measures may include CMB-01 
(``Transition to Zero and Near-Zero Emission Technologies for 
Stationary Sources''), CMB-02 (``Emission Reductions from Replacement 
with Zero or Near-Zero NOX Appliances in Commercial and 
Residential Applications''), CMB-03 (``Emission Reductions from Non-
Refinery Flares''), CMB-04 (``Emission Reductions from Restaurant 
Burners and Residential Cooking''), ECC-02 (``Co-Benefits from Existing 
Residential and Commercial Building Energy Efficiency Measures''), ECC-
03 (``Additional Enhancements in Reducing Residential Building Energy 
Use''), MOB-10 (``Extension of the SOON Provision for Construction/
Industrial Equipment''), MOB-11 (``Extended Exchange Program''), and 
MOB-14 (``Emission Reductions from Incentive Programs'').\163\
---------------------------------------------------------------------------

    \163\ 2016 PM2.5 Plan, Table VI-C-6.
---------------------------------------------------------------------------

    For on-road and non-road mobile sources, which represent the 
largest sources of NOX emissions in the nonattainment area, 
the 2016 PM2.5 Plan lists numerous CARB regulations and 
discusses the key regulations that limit emissions of direct 
PM2.5 as well as NOX, SO2, VOC, and 
ammonia from these sources.\164\ For example, the regulations that 
apply to the three largest sources of NOX in the South 
Coast--heavy-duty diesel trucks, light- and medium-duty passenger 
vehicles, and off-road equipment--are discussed in the 2016 
PM2.5 Plan at Appendix VI-C, Attachment VI-C-1, ``California 
Existing Mobile Source Control Program,'' and CARB's emission 
projections for these sources are presented in the Plan's emissions 
inventory.\165\ The Plan also shows that NOX emission levels 
in the 2019 and 2022 milestone years are projected to be below the 
levels needed to show generally linear progress toward attainment in 
2025.\166\
---------------------------------------------------------------------------

    \164\ Id., Appendix VI-C, Attachment VI-C-1.
    \165\ Id., Appendix III.
    \166\ Id., Table VI-C-5A.
---------------------------------------------------------------------------

    The Truck and Bus Regulation and Drayage Truck Regulation became 
effective in 2011 and have rolling compliance deadlines based on truck 
engine model year. These and other regulations applicable to heavy-duty 
diesel trucks will continue to reduce emissions of diesel PM and 
NOX through the RFP planning years.\167\ For example, model 
year 1994 and 1995 heavy-duty diesel truck engines were required to be 
upgraded to meet the 2010 model year truck engine emission standards by 
2016, and model year 1996-1999 engines must be upgraded by January 1, 
2020.\168\
---------------------------------------------------------------------------

    \167\ Id. at VI-C-20.
    \168\ Title 13, California Code of Regulations, Section 2025 
(``Regulation to Reduce Emissions of Diesel Particulate Matter, 
Oxides of Nitrogen and Other Criteria Pollutants, from In-Use Heavy-
Duty Diesel-Fueled Vehicles''), paragraphs (e), (f), and (g), 
effective December 14, 2011. See also 77 FR 20308, 20309-20310 
(April 4, 2012) (final rule approving CARB's Truck and Bus Rule into 
California SIP).

---------------------------------------------------------------------------

[[Page 40046]]

    CARB's Cleaner In-Use Off-road Equipment regulation was first 
approved in 2007 to reduce PM2.5 and NOX 
emissions from in-use off-road heavy-duty diesel vehicles in California 
such as those used in construction, mining, and industrial operations. 
The regulation reduces emissions of PM2.5 and NOX 
by targeting the existing fleet and imposing idling limits, 
restrictions on use of older vehicles, and requirements to retrofit or 
replace the oldest engines. For example, Tier 0 engines could not be 
added to fleets after January 1, 2014, and Tier 1 engines could not be 
added after January 1, 2016. The regulation was phased in between 
January 1, 2014 and January 1, 2019.\169\
---------------------------------------------------------------------------

    \169\ 2016 PM2.5 Plan, Appendix VI-C, Attachment VI-
C-1, VI-C-23 and VI-C-24.
---------------------------------------------------------------------------

Volatile Organic Compounds
    As with other precursors, the District regulates stationary and 
area sources of VOCs, and CARB is largely responsible for regulating 
emissions from both on-road and off-road mobile sources. The 2016 
PM2.5 Plan highlights one adopted stationary source VOC rule 
that contributes to RFP: Rule 1114 (``Petroleum Refinery Coking 
Operations'').\170\
---------------------------------------------------------------------------

    \170\ Id., Table VI-C-4. See also, email dated September 12, 
2019 from Kalam Cheung, SCAQMD, to Ashley Graham, EPA Region IX, 
attaching spreadsheet entitled ``Draft Rule Adoption since 2016 AQMP 
20190809.xlsx.''
---------------------------------------------------------------------------

    In addition to the baseline measures discussed above, the District 
intends to adopt and implement several measures to reduce 
NOX emissions that may also result in VOC emission 
reductions and help ensure RFP toward attainment of the 2012 
PM2.5 NAAQS in the South Coast air basin. These measures 
include CMB-01 (``Transition to Zero and Near-Zero Emission 
Technologies for Stationary Sources''), CMB-03 (``Emission Reductions 
from Non-Refinery Flares''), ECC-02 (``Co-Benefits from Existing 
Residential and Commercial Building Energy Efficiency Measures''), ECC-
03 (``Additional Enhancements in Reducing Residential Building Energy 
Use'').\171\
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    \171\ Id.
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    As with NOX, the majority of VOC emission reductions 
that occur between the 2012 base year and the 2022 RFP year come from 
on-road mobile sources and other mobile sources that are under the 
State's jurisdiction.
Ammonia
    Control measures for ammonia sources are described in Appendix VI 
of the 2016 PM2.5 Plan. For example, South Coast Rule 223 
and Rule 1127, which regulate confined animal facilities and manure 
waste from these facilities, control ammonia, as do the District's 
composting measures (i.e., Rule 1133, Rule 1133.1, Rule 1133.2 and Rule 
1133.3). These rules and the methods they use to control ammonia 
emissions are discussed at length in Appendix IV-A of the Plan, and 
their emission projections are presented collectively under farming 
operations (for confined animal feeding operations and manure) or waste 
disposal (for composting categories) in the Plan's emissions 
inventory.\172\ We discuss our evaluation of these rules for purposes 
of satisfying RACM requirements in section V.D of this proposed rule.
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    \172\ 2016 PM2.5 Plan, IV-A-98 to IV-A-103.
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    As part of the control strategy for the 2016 PM2.5 Plan, 
the District has committed to adopt and implement new or revised 
control measures to reduce ammonia emissions in the South Coast air 
basin. Potential measures include: (1) BCM-04 (``Emission Reductions 
from Manure Management Strategies''), which would reduce ammonia from 
fresh manure through acidifier application, dietary manipulation, feed 
additives, and other manure control strategies, including potentially 
lowering the threshold for large confined animal facilities under Rule 
223; and (2) BCM-10 (``Emission Reductions from Greenwaste 
Composting''), which would reduce ammonia through emerging organic 
waste processing technology and potential restrictions on direct land 
application of uncomposted greenwaste.\173\
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    \173\ SCAQMD, Governing Board Resolution No. 17-2 (March 3, 
2017), 9 and 2016 PM2.5 Plan, Table 4-7, identifying BCM-
04 and BCM-10 as new control measures to be implemented by 2020 for 
PM2.5 purposes.
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    The District ascribes the projected reductions in ammonia during 
the period from 2012 to 2022 to decreases in farming operations in the 
South Coast air basin, reductions in emissions from mobile sources 
largely achieved by State regulations for on-road motor vehicles, and 
the District's commitments to adopt and implement new control measures 
such as BCM-04 and BCM-10.\174\
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    \174\ 2016 PM2.5 Plan, Appendix III, Attachment A.
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Sulfur Dioxide
    Reductions of SO2 in the South Coast nonattainment area 
during the period from 2012 to 2022 are mainly from mobile source 
reductions. The majority of the SO2 reductions come from 
non-road mobile sources, primarily reductions from state regulation of 
ocean-going vessels.
Quantitative Milestones
    The 2016 PM2.5 Plan identifies a milestone year of 2019, 
which is 4.5 years after the effective date of the EPA's designation 
and classification of the South Coast as a Moderate nonattainment area 
for the 2012 PM2.5 NAAQS, and a second milestone year of 
2022, which is 7.5 years after the effective date of the designation. 
The Plan also identifies target RFP emission levels for direct 
PM2.5, NOX, SO2, VOC, and ammonia for 
the 2019 milestone year and the 2022 post-attainment milestone 
year,\175\ and emission reduction commitments to be achieved through 
2022 in accordance with the control strategy in the Plan.\176\
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    \175\ 2016 PM2.5 Plan, VI-C-9 and VI-C-10.
    \176\ Id., Table VI-C-6.
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3. The EPA's Evaluation and Proposed Action
    The 2016 PM2.5 Plan describes the adopted control 
measures for direct PM2.5, NOX, SO2, 
VOC, and ammonia implemented during each year of the plan and 
demonstrates that these measures are being implemented as expeditiously 
as practicable. Additionally, the Plan presents basin-wide emission 
reduction commitments to attain the 2012 PM2.5 NAAQS. The 
Plan contains projected RFP emission levels for direct PM2.5 
and all PM2.5 precursors for the 2019 and 2022 milestone 
years based on the anticipated implementation schedule for the control 
strategy. Finally, the 2016 PM2.5 Plan demonstrates that, by 
the end of the calendar year for each milestone date for the area, 
emissions of direct PM2.5 and all PM2.5 
precursors will be reduced at rates representing generally linear 
progress towards attainment.\177\ We agree with the State and 
District's conclusion that generally linear progress is an appropriate 
measure of RFP for the 2012 PM2.5 NAAQS in the South Coast 
area given that PM2.5 and its precursors are emitted by a 
large number and range of sources in the South Coast, the emission 
reductions needed for these

[[Page 40047]]

pollutants are inventory-wide,\178\ and secondary particulates 
contribute significantly to ambient PM2.5 levels in the 
South Coast area.\179\
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    \177\ In addition to the Moderate area plan and request for 
reclassification to Serious, the 2016 PM2.5 Plan includes 
a Serious area attainment demonstration for the 2012 
PM2.5 NAAQS with a December 31, 2025 attainment date. The 
RFP demonstration in the 2016 PM2.5 Plan represents 
generally linear progress between the 2012 base year and projected 
2025 attainment year in the Serious area plan. Given that the Plan 
identifies December 31, 2025 as the most expeditious attainment date 
for the area, we find this date to be an appropriate end point for 
the RFP demonstration.
    \178\ 2016 PM2.5 Plan, Appendix IV-A, Appendix IV-B, 
and Appendix VI-A.
    \179\ Id. at V-6-61.
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    Additionally, the 2016 PM2.5 Plan identifies 
quantitative milestone dates that are consistent with the requirements 
of 40 CFR 51.1013(a)(4) and target emission levels for direct 
PM2.5 and all PM2.5 precursors to be achieved by 
these milestone dates through implementation of the control strategy. 
These target emission levels and associated control requirements 
provide for objective evaluation of the area's progress towards 
attainment of the 2012 PM2.5 NAAQS.
    For all of these reasons, we propose to approve the RFP 
demonstration in the 2016 PM2.5 Plan as meeting the 
requirements of CAA section 172(c)(2) and 40 CFR 51.1012(a) and to 
determine that the quantitative milestones in the Plan satisfy the 
requirements of CAA section 189(c) and 40 CFR 51.1013.
    On January 13, 2020, CARB submitted the ``2019 Quantitative 
Milestone Report for the 2012 annual PM2.5 National Ambient 
Air Qualtiy Standard (January 2020)'' (``2019 QM Report'') to the 
EPA.\180\ The 2019 QM Report includes a certification from the 
Governor's designee that the 2019 quantitative milestones for the South 
Coast PM2.5 nonattainment area have been achieved and a 
demonstration that the adopted control strategy has been fully 
implemented. The 2019 QM Report also contains a demonstration of how 
the emission reductions achieved to date compare to those required or 
scheduled to meet RFP. The State and District conclude in the 2019 QM 
Report that the emission reductions needed to demonstrate RFP have been 
achieved and that the 2019 quantitative milestone has been met in the 
South Coast. On March 30, 2020, the EPA determined that the South Coast 
2019 QM Report was adequate.\181\ We invite the public to comment on 
this determination of adequacy.
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    \180\ Letter dated January 13, 2020, from Richard W. Corey, 
Executive Officer, CARB, to Mike Stoker, Regional Administrator, EPA 
Region IX, with enclosure.
    \181\ Letter dated March 30, 2020, from Andrew R. Wheeler, 
Administrator, EPA, to Richard W. Corey, Executive Officer, CARB, 
regarding 2019 Quantitative Milestone Report for the 2012 annual 
PM2.5 National Ambient Air Quality Standards.
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H. Contingency Measures

1. Requirements for Contingency Measures
    Under CAA section 172(c)(9), each SIP for a nonattainment area must 
include contingency measures to be implemented if an area fails to meet 
RFP (``RFP contingency measures'') or fails to attain the NAAQS by the 
applicable attainment date (``attainment contingency measures''). Under 
the PM2.5 SIP Requirements Rule, PM2.5 attainment 
plans must include contingency measures to be implemented following a 
determination by the EPA that the state has failed: (1) To meet any RFP 
requirement in the approved SIP; (2) to meet any quantitative milestone 
in the approved SIP; (3) to submit a required quantitative milestone 
report; or (4) to attain the applicable PM2.5 NAAQS by the 
applicable attainment date.\182\ Section 189(b)(1)(A) of the CAA, 
however, differentiates between attainment plans that provide for 
timely attainment and those that demonstrate that attainment is 
impracticable. Where a SIP includes a demonstration that attainment by 
the applicable attainment date is impracticable, the state need only 
submit contingency measures to be implemented if an area fails to meet 
RFP, to meet a SIP-approved quantitative milestone, or to submit a 
required quantitative milestone report.\183\ Contingency measures must 
be fully adopted rules or control measures that are ready to be 
implemented quickly upon failure to meet RFP or failure of the area to 
meet the relevant NAAQS by the applicable attainment date.\184\
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    \182\ 40 CFR 51.1014(a).
    \183\ The EPA does not interpret the requirement for failure-to-
attain contingency measures to apply to a Moderate PM2.5 
nonattainment area that a state demonstrates cannot practicably 
attain the NAAQS by the statutory attainment date. Rather, the EPA 
believes it is appropriate for the state to identify and adopt 
attainment contingency measures as part of the Serious area 
attainment plan. 81 FR 58010, 58067 and Addendum, 42015.
    \184\ 81 FR 58010, 58066 and Addendum, 42015.
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    The purpose of contingency measures is to continue progress in 
reducing emissions while a state revises its SIP to meet the missed RFP 
requirement or to correct ongoing nonattainment. Neither the CAA nor 
the EPA's implementing regulations establish a specific level of 
emission reductions that implementation of contingency measures must 
achieve, but the EPA recommends that contingency measures should 
provide for emission reductions equivalent to approximately one year of 
reductions needed for RFP, calculated as the overall level of 
reductions needed to demonstrate attainment divided by the number of 
years from the base year to the attainment year. In general, we expect 
all actions needed to effect full implementation of the measures to 
occur within 60 days after the EPA notifies the state of a failure to 
meet RFP or to attain.\185\
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    \185\ 81 FR 58010, 58066. See also General Preamble, 13512, 
13543-13544, and Addendum, 42014-42015.
---------------------------------------------------------------------------

    To satisfy the requirements of 40 CFR 51.1014, the contingency 
measures adopted as part of a PM2.5 attainment plan must 
consist of control measures for the area that are not otherwise 
required to meet other nonattainment plan requirements (e.g., to meet 
RACM/RACT requirements) and must specify the timeframe within which 
their requirements become effective following any of the EPA 
determinations specified in 40 CFR 51.1014(a).
    In a 2016 decision called Bahr v. EPA (``Bahr''),\186\ the Ninth 
Circuit Court of Appeals rejected the EPA's interpretation of CAA 
section 172(c)(9) to allow approval of already implemented control 
measures as contingency measures. In Bahr, the Ninth Circuit concluded 
that contingency measures must be measures that are triggered only 
after the EPA determines that an area fails to meet RFP requirements or 
to attain by the applicable attainment date, not before. Thus, within 
the geographic jurisdiction of the Ninth Circuit, already implemented 
measures cannot serve as contingency measures under CAA section 
172(c)(9).
---------------------------------------------------------------------------

    \186\ Bahr v. EPA, 836 F.3d 1218, 1235-1237 (9th Cir. 2016).
---------------------------------------------------------------------------

    To comply with section 172(c)(9), as interpreted in the Bahr 
decision, a state must develop, adopt, and submit a contingency measure 
to be triggered upon a failure to meet an RFP milestone, failure to 
meet a quantitative milestone requirement, or failure to attain the 
NAAQS by the applicable attainment date regardless of the extent to 
which already-implemented measures would achieve surplus emission 
reductions beyond those necessary to meet RFP or quantitative milestone 
requirements and beyond those predicted to achieve attainment of the 
NAAQS.
2. Contingency Measures in the 2016 PM2.5 Plan
    The 2016 PM2.5 Plan addresses the contingency measure 
requirement in Chapter 4 of the Plan and in section H of the CARB Staff 
Report. Chapter 4 of the 2016 PM2.5 Plan addresses 
contingency measures for failure to attain the 2006 PM2.5 
NAAQS by

[[Page 40048]]

describing emission reductions to be achieved by an adopted measure, 
South Coast Rule 445 (``Wood-Burning Devices).\187\ The 2016 
PM2.5 Plan does not specifically address contingency 
measures for failure to meet RFP or quantitative milestone 
requirements. The CARB Staff Report provides a brief statement 
acknowledging the Bahr decision and committing to work with the EPA and 
the District to provide additional documentation or develop any needed 
SIP revisions consistent with that decision.\188\
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    \187\ 2016 PM2.5 Plan, 4-51 to 4-52.
    \188\ The SCAQMD and CARB adopted the 2016 PM2.5 Plan 
in March and April 2017, shortly after the Ninth Circuit issued its 
decision in Bahr.
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    To supplement the contingency measure element of the 2016 
PM2.5 Plan, CARB submitted a letter dated January 29, 2019 
enclosing the District's commitment to adopt a control measure by a 
date certain for purposes of satisfying CAA contingency measure 
requirements for the 2006 and 2012 PM2.5 NAAQS.\189\ By 
letter dated February 12, 2020, the District clarified its commitment 
by committing to develop, adopt, and submit to CARB, for submission to 
the EPA, a revised rule containing specific contingency provisions that 
would become effective if the EPA determines: (1) That the area failed 
to attain the 2006 24-hour PM2.5 NAAQS or the 2012 annual 
PM2.5 NAAQS by the applicable attainment date; (2) that the 
area failed to meet any RFP requirement; (3) that the area failed to 
meet any quantitative milestone; or (4) that the State failed to submit 
a required quantitative milestone report for the area.\190\ The 
District submitted this clarified commitment, accompanied by a 
technical analysis of the emission reductions to be achieved by the 
contingency measure (``Technical Clarification''), to satisfy the 
attainment contingency measure requirement for the 2006 
PM2.5 NAAQS and the RFP contingency measure requirement for 
the 2012 PM2.5 NAAQS in the South Coast nonattainment 
area.\191\
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    \189\ Letter dated February 13, 2019, from Michael Benjamin, Air 
Quality Planning and Science Division, CARB, to Mike Stoker, 
Regional Administrator, EPA Region IX (transmitting letter dated 
January 29, 2019, from Wayne Nastri, Executive Officer, SCAQMD, to 
Richard Corey, Executive Officer, CARB). In its January 29, 2019 
letter, the District committed to modify an existing rule or adopt a 
new rule to create a contingency measure that would be triggered if 
the area fails to meet an RFP requirement, to submit a quantitative 
milestone report, to meet a quantitative milestone, or to attain the 
2006 24-hour or 2012 annual PM2.5 NAAQS.
    \190\ Letter dated February 12, 2020, from Wayne Nastri, 
Executive Officer, SCAQMD, to Richard Corey, Executive Officer, CARB 
(attaching ``Technical clarification regarding emission reductions 
associated with contingency measures for the 2006 24-hour 
PM2.5 standard attainment and 2012 annual 
PM2.5 standard Reasonable Further Progress,'' February 
2020) (``Technical Clarification'').
    \191\ Id.
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    Specifically, the District has committed to revise an existing 
rule, Rule 445 (``Wood Burning Devices''), to establish more stringent 
requirements that would become effective if the EPA makes any of the 
four determinations (i.e., ``findings of failure'') listed in 40 CFR 
51.1014(a). The revisions are to lower the PM wood burning curtailment 
threshold to 29 [micro]g/m\3\ upon the first EPA finding of failure, 
and to lower the threshold to 28, 27, and 26 [micro]g/m\3\ upon a 
second, third, and fourth finding of failure, respectively. Under the 
revised rule, the mandatory winter burning curtailment would apply to 
the entire South Coast air basin. The District estimates that lowering 
the curtailment threshold to 29, 28, 27, and 26 [micro]g/m\3\ upon each 
finding of failure would achieve reductions in PM2.5 
emissions of 20.9, 20.9, 13.9, and 19.1 tpy, respectively.\192\
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    \192\ Technical Clarification, 2.
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    The District has committed to adopt this revised rule and submit it 
to CARB in time for CARB to submit the revised rule to the EPA by the 
earlier of the following dates: (1) One year after the date of the 
EPA's conditional approval of the contingency measures for the 2012 
annual PM2.5 standard, or (2) 60 days after the date the EPA 
makes a determination that the South Coast area has failed to attain 
the 2006 24-hour PM2.5 standards but no later than one year 
after the date of the EPA's conditional approval of the contingency 
measures for these standards.\193\ In its March 3, 2020 letter 
submitting the District's commitment to the EPA, CARB also committed to 
submit the revised rule to the EPA by the earlier of these two 
dates.\194\
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    \193\ Letter dated February 12, 2020, from Wayne Nastri, 
Executive Officer, SCAQMD, to Richard Corey, Executive Officer, 
CARB.
    \194\ Letter dated March 3, 2020, from Michael T. Benjamin, 
Chief, Air Quality Planning and Science Division, CARB, to Amy 
Zimpfer, Associate Director, Air Division, EPA Region IX 
(transmitting letter dated February 12, 2020, from Wayne Nastri, 
Executive Officer, SCAQMD, to Richard Corey, Executive Officer, 
CARB).
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3. The EPA's Evaluation and Proposed Action
    Section 172(c)(9) requires contingency measures to address 
potential failure to achieve RFP milestones, failure to meet 
requirements concerning quantitative milestones, and failure to attain 
the NAAQS by the applicable attainment date. For purposes of evaluating 
the contingency measure element of the 2016 PM2.5 Plan, we 
find it useful to distinguish between contingency measures to address 
potential failure to achieve RFP milestones or to meet quantitative 
milestone requirements (``RFP contingency measures'') and contingency 
measures to address potential failure to attain the NAAQS (``attainment 
contingency measures'').
2006 PM2.5 Serious Area Contingency Measure Requirements
    The EPA previously approved those portions of the 2016 
PM2.5 Plan that pertain to the requirements for implementing 
the 2006 PM2.5 NAAQS in the South Coast, except for the 
contingency measure component of the Plan.\195\ As part of that action, 
the EPA found that, for purposes of the 2006 PM2.5 NAAQS, 
the requirement for RFP contingency measures was moot as applied to the 
2017 milestone year because CARB and the District had demonstrated to 
the EPA's satisfaction that the 2017 quantitative milestones in the 
plan had been met.\196\ The EPA took no action, however, with respect 
to RFP contingency measures for the 2020 milestone year or attainment 
contingency measures for the 2006 PM2.5 NAAQS. Thus, the EPA 
is now proposing to act on these outstanding components of the 2016 
PM2.5 Plan for purposes of the 2006 PM2.5 NAAQS.
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    \195\ 84 FR 3305 (February 12, 2019).
    \196\ Id. and 83 FR 49872, 49890 (October 3, 2018) (referencing 
the EPA's September 7, 2018 adequacy determination).
---------------------------------------------------------------------------

    The applicable quantitative milestone dates for the Serious area 
plan for the 2006 PM2.5 NAAQS are December 31, 2017 and 
December 31, 2020.\197\ We discuss below our evaluation of the 2016 
PM2.5 Plan and related State and District commitments for 
compliance with the 2020 RFP and attainment contingency measure 
requirements for the 2006 PM2.5 NAAQS.
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    \197\ 40 CFR 51.1013(a)(4).
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2012 PM2.5 Moderate Area Contingency Measure Requirements
    Because we are proposing to approve the State's demonstration that 
the South Coast area cannot practicably attain the 2012 
PM2.5 NAAQS by the applicable Moderate area attainment date 
of December 31, 2021, and to reclassify the area to Serious on this 
basis, attainment contingency measures are not required as part of the 
Moderate area plan for the 2012 PM2.5 NAAQS. Upon 
reclassification of the South Coast area as a Serious area, California 
will be required to adopt attainment contingency measures as part of 
the Serious area attainment plan for the 2012 PM2.5 NAAQS.

[[Page 40049]]

    With respect to the RFP contingency measure requirement for the 
2012 PM2.5 NAAQS, the applicable quantitative milestone 
dates are October 15, 2019 and October 15, 2022. As explained in 
section V.G.3 of this proposed rule, on January 13, 2020, CARB 
submitted a quantitative milestone report demonstrating that the 2019 
quantitative milestones in the 2016 PM2.5 Plan have been 
achieved, and the EPA has determined that this milestone report is 
adequate. Because the State and District have demonstrated that the 
South Coast area has met its 2019 quantitative milestones, RFP 
contingency measures for the 2019 milestone year are no longer needed. 
The sole purpose of RFP contingency measures is to provide continued 
progress if an area fails to meet its RFP or quantitative milestone 
requirements. Failure to meet RFP or quantitative milestone 
requirements for 2019 would have required California to implement RFP 
contingency measures and, in certain cases, to revise the 2016 
PM2.5 Plan to assure that the area would achieve the next 
quantitative milestone (i.e., for 2022).\198\ In this case, however, 
the 2019 QM Report demonstrates that actual emission levels in 2019 
were consistent with the approved 2019 RFP milestone year targets for 
direct PM2.5 and all precursor pollutants (NOX, 
SO2, VOC, and ammonia) regulated in the 2016 
PM2.5 Plan. Accordingly, RFP contingency measures for 2019 
no longer have meaning or purpose, and the EPA proposes to find that 
the requirement for them is now moot as applied to the South Coast. We 
discuss below our evaluation of the 2016 PM2.5 Plan and 
related State and District commitments for compliance with the 2022 RFP 
contingency measure requirement for the 2012 PM2.5 NAAQS.
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    \198\ Under section 189(c)(3) of the CAA, if a state fails to 
submit a required quantitative milestone report or the EPA 
determines that the area has not met an applicable milestone, the 
EPA must require the state, within nine months after such failure or 
determination, to submit a plan revision that assures that the state 
will achieve the next milestone (or attain the NAAQS, if there is no 
next milestone) by the applicable date.
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The State's Contingency Measure Commitment
    The District and CARB have committed to develop, adopt, and submit 
a revised District rule (Rule 445, ``Wood-Burning Devices'') to meet 
the attainment contingency measure requirement for the 2006 
PM2.5 NAAQS and the RFP contingency measure requirement for 
the 2012 PM2.5 NAAQS. The specific revisions the District 
has committed to make (i.e., increasing the stringency of the existing 
wood burning curtailment provisions in Rule 445) would satisfy the 
requirements in CAA section 172(c)(9) because they would be undertaken 
if the area fails to attain or fails to meet an RFP or quantitative 
milestone requirement, and would take effect without significant 
further action by the State or the EPA. The revised rule would also 
comply with the regulatory requirements in 40 CFR 51.1014 because it 
would contain contingency provisions that take effect if the EPA makes 
any of the four determinations listed in 40 CFR 51.1014(a), would 
consist of control requirements not otherwise included in the control 
strategy, and would specify the timeframe within which its contingency 
provisions become effective following any of the determinations listed 
in 40 CFR 51.1014(a).
    We also considered the adequacy of the contingency measure (once 
adopted and submitted) from the standpoint of the magnitude of emission 
reductions the measure would provide (if triggered). Neither the CAA 
nor the EPA's implementing regulations for the PM2.5 NAAQS 
establish a specific amount of emission reductions that implementation 
of contingency measures must achieve, but we generally expect that 
contingency measures should provide for emission reductions 
approximately equivalent to one year's worth of RFP. For the 2006 
PM2.5 NAAQS in the South Coast, one year's worth of 
reductions is approximately 0.36 of direct PM2.5 reductions, 
26.68 tpd of NOX reductions, 0.26 tpd of SOX 
reductions, 13.50 tpd of VOC reductions, and 1.02 tpd of ammonia 
reductions.\199\ For the 2012 PM2.5 NAAQS, one year's worth 
of reductions needed for RFP is approximately 0.18 tpd of direct 
PM2.5 reductions, 25.71 tpd of NOX reductions, 
0.08 tpd of SOX reductions, 10.33 tpd of VOC reductions, and 
0.67 tpd of ammonia reductions.\200\
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    \199\ Technical Clarification, Table 1.
    \200\ 2016 PM2.5 Plan, Appendix III, Attachment A.
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    With respect to attainment contingency measures for the 2006 
PM2.5 NAAQS, the Technical Clarification contains the 
District's quantification of the expected emission reductions from the 
strengthened requirements to be adopted as contingency measures in Rule 
445. The District estimates that lowering the curtailment threshold in 
Rule 445 by 1 [micro]g/m\3\ for each finding of failure (i.e., to 29, 
28, 27, and 26 [micro]g/m\3\) would achieve additional reductions in 
PM2.5 emissions of 20.9, 20.9, 13.9, and 19.1 tpy (0.06, 
0.06, 0.04, and 0.05 tpd), respectively, in 2020, the year after the 
attainment year for the 2006 PM2.5 NAAQS.\201\ Each of these 
reduction levels alone do not achieve one year's worth of RFP. However, 
the District's submittal provides the larger SIP planning context in 
which to judge the adequacy of the to-be-submitted District contingency 
measure by identifying surplus direct PM2.5, NOX, 
VOC, and ammonia emission reductions estimated to be achieved in 
2020.\202\ The surplus reflects already implemented regulations, 
including vehicle turnover, which refers to the ongoing replacement by 
individuals, companies, and government agencies of older, more 
polluting vehicles and engines with newer vehicles and engines designed 
to meet more stringent CARB mobile source emissions standards. The 
surplus also reflects additional emission reductions from regulations 
and programs that were adopted after the development of the 2016 
PM2.5 Plan. These include CARB's Heavy-Duty Vehicle 
Inspection Program, Periodic Smoke Inspection Program, and efforts to 
reduce emissions from Ocean-Going Vessels At-Berth, and the District's 
Airports Memorandum of Understanding, Metrolink Locomotives, Low Carbon 
Fuel Standard and Alternative Diesel Fuels Regulation, and Airborne 
Toxic Control Measure (ATCM) for Portable Engines and the Statewide 
Portable Equipment Registration Program.\203\
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    \201\ Technical Clarification, 2-3.
    \202\ These emission reductions are surplus to those relied upon 
in the control strategy for attaining the 2006 PM2.5 
NAAQS in the 2016 PM2.5 Plan because they occur after the 
December 31, 2019 attainment date and/or will be achieved through 
implementation of measures adopted after the Plan's adoption.
    \203\ Technical Clarification, 2-4.
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    We have reviewed the surplus emissions estimates for 2020, as shown 
in the Technical Clarification, and find the calculations reasonable. 
We therefore agree with the District's conclusion that the 2016 
PM2.5 Plan provides surplus emission reductions beyond those 
necessary to demonstrate attainment by the December 31, 2019 Serious 
area attainment date for the 2006 PM2.5 NAAQS in the South 
Coast. While such surplus emission reductions in the year after the 
2019 attainment year do not represent contingency measures themselves, 
we consider them relevant in evaluating the adequacy of the contingency 
measures that the State has committed to in order to meet the 
requirements of section 172(c)(9). In light of the ongoing reductions 
in emissions of direct PM2.5, NOX, VOC, and 
ammonia achieved by the State and District measures identified in the 
Technical Clarification, the emission

[[Page 40050]]

reductions from the District contingency measure (revised Rule 445) 
would be sufficient to meet the attainment contingency measure 
requirement for the 2006 PM2.5 NAAQS, even though the 
measure would achieve emission reductions lower than the EPA normally 
recommends for reductions from such a measure.
    With respect to RFP contingency measures for the 2022 milestone 
year in the Moderate area plan for the 2012 PM2.5 NAAQS, the 
District similarly explains in the Technical Clarification that 
continuing implementation of existing regulations and turn-over of 
older vehicles and equipment to cleaner vehicles and equipment will 
result in surplus emission reductions in the 2022 RFP milestone 
year.\204\ In light of these ongoing reductions in emissions of direct 
PM2.5, NOX, VOC, and ammonia, the District 
contingency measure (revised Rule 445) would be sufficient to meet the 
2022 RFP contingency measure requirement for the 2012 PM2.5 
NAAQS, even though the measure would not by itself achieve emission 
reductions equivalent to one year's worth of RFP. For the same reasons, 
the District contingency measure (revised Rule 445) would be sufficient 
to meet the 2020 RFP contingency measure requirement for the 2006 
PM2.5 NAAQS. We note that under the proposed revisions to 
Rule 445, if the EPA determines that the South Coast area has failed to 
attain the 2006 PM2.5 NAAQS by the December 31, 2019 
attainment date and thereby triggers the contingency measure provision 
to lower the mandatory burning curtailment to 29 [micro]g/m\3\, the 
State would not be required to submit a new contingency measure because 
the additional provisions to lower the curtailment threshold to 28, 27, 
and 26 [micro]g/m\3\ could be triggered upon subsequent failures and 
therefore would satisfy RFP contingency measure requirements for both 
the 2006 PM2.5 NAAQS and the 2012 PM2.5 NAAQS.
---------------------------------------------------------------------------

    \204\ Id. at 4-6.
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    Finally, CARB has committed to submit the revised rule to the EPA 
within one year after a final action conditionally approving the 
contingency measure element of the 2016 PM2.5 Plan, or 
within 60 days of a determination by the EPA that the South Coast area 
failed to attain the 2006 PM2.5 NAAQS by the applicable 
attainment date, whichever occurs sooner. Section 110(k)(4) of the Act 
authorizes the EPA to conditionally approve a plan revision based on a 
commitment by the state to adopt specific enforceable measures by a 
date certain, but not later than one year after the date of approval of 
the plan revision. The outermost deadline in CARB's commitment (one 
year following conditional approval of the plan revision) is consistent 
with the submission deadline in CAA section 110(k)(4). If, however, the 
EPA determines that the South Coast area failed to attain the 2006 
PM2.5 NAAQS by the applicable attainment date (December 31, 
2019), and the date 60 days after this determination is earlier than 
the 1-year deadline under section 110(k)(4), then CARB would be 
obligated under its commitment to submit the revised rule to the EPA by 
the earlier date. These deadlines ensure that, should the EPA determine 
that the South Coast area failed to timely attain the 2006 
PM2.5 NAAQS, contingency provisions will take effect within 
60 days of the determination, consistent with longstanding EPA 
guidance.
    For these reasons, we propose to conditionally approve the 
contingency measure element of the 2016 PM2.5 Plan for the 
2006 PM2.5 NAAQS and the 2012 PM2.5 NAAQS, as 
supplemented by commitments from the District and CARB to adopt and 
submit an additional contingency measure to meet the attainment and RFP 
contingency measure requirements of CAA section 172(c)(9) for these 
NAAQS. Our proposed approval is conditional because it relies upon 
commitments to adopt and submit a specific enforceable contingency 
measure (i.e., a revised District rule with contingent provisions).

I. Motor Vehicle Emissions Budgets

1. Requirements for Motor Vehicle Emissions Budgets
    Section 176(c) of the CAA requires federal actions in nonattainment 
and maintenance areas to conform to the SIP's goals of eliminating or 
reducing the severity and number of violations of the NAAQS and 
achieving timely attainment of the standards. Conformity to the SIP's 
goals means that such actions will not: (1) Cause or contribute to 
violations of a NAAQS, (2) worsen the severity of an existing 
violation, or (3) delay timely attainment of any NAAQS or any interim 
milestone.
    Actions involving Federal Highway Administration (FHWA) or Federal 
Transit Administration (FTA) funding or approval are subject to the 
EPA's transportation conformity rule, codified at 40 CFR part 93, 
subpart A. Under this rule, metropolitan planning organizations (MPOs) 
in nonattainment and maintenance areas coordinate with state and local 
air quality and transportation agencies, the EPA, the FHWA, and the FTA 
to demonstrate that an area's regional transportation plans and 
transportation improvement programs conform to the applicable SIP. This 
demonstration is typically done by showing that estimated emissions 
from existing and planned highway and transit systems are less than or 
equal to the motor vehicle emissions budgets (MVEBs or ``budgets'') 
contained in all control strategy SIPs. An attainment, maintenance, or 
RFP SIP should include budgets for the attainment year, each required 
RFP milestone year, and the last year of the maintenance plan, as 
appropriate. Budgets are generally established for specific years and 
specific pollutants or precursors and must reflect all of the motor 
vehicle control measures contained in the attainment and RFP 
demonstrations.\205\
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    \205\ 40 CFR 93.118(e)(4)(v).
---------------------------------------------------------------------------

    Under the PM2.5 SIP Requirements Rule, each attainment 
plan submittal for a Moderate PM2.5 nonattainment area must 
contain quantitative milestones to be achieved no later than 4.5 years 
and 7.5 years after the date the area was designated 
nonattainment.\206\ The second of these milestone dates, October 15, 
2022,\207\ falls after the attainment date for the South Coast area, 
which is December 31, 2021. As the EPA explained in the preamble to the 
PM2.5 SIP Requirements Rule, it is important to include a 
post-attainment year quantitative milestone to ensure that, if the area 
fails to attain by the attainment date, the EPA can continue to monitor 
the area's progress toward attainment while the state develops a new 
attainment plan.\208\ Moderate area plans demonstrating that attainment 
by the Moderate area attainment date is impracticable must, therefore, 
include budgets for both of the milestone dates. States that submit 
impracticability demonstrations for Moderate areas under CAA section 
189(a)(1)(B)(ii), however, are not required to submit budgets for the 
attainment year because the submitted SIP does not demonstrate 
attainment.\209\
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    \206\ 40 CFR 51.1013(a)(1).
    \207\ Because the South Coast area was designated nonattainment 
effective April 15, 2015, the first milestone date is October 15, 
2019, and the second milestone date is October 15, 2022. 80 FR 2206.
    \208\ 81 FR 58010, 58058 and 58063-58064.
    \209\ Id. at 58055.
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    PM2.5 plans should identify budgets for direct 
PM2.5, NOX, and all other PM2.5 
precursors for which on-road emissions are determined to significantly 
contribute to PM2.5 levels in the area for each RFP 
milestone year and the attainment year, if the plan demonstrates 
attainment. All direct PM2.5 SIP budgets should include 
direct PM2.5 motor vehicle emissions from

[[Page 40051]]

tailpipes, brake wear, and tire wear. With respect to PM2.5 
from re-entrained road dust and emissions of VOC, SO2, and/
or ammonia, the transportation conformity provisions of 40 CFR part 93, 
subpart A, apply only if the EPA Regional Administrator or the director 
of the state air agency has made a finding that emissions of these 
pollutants within the area are a significant contributor to the 
PM2.5 nonattainment problem and has so notified the MPO and 
Department of Transportation (DOT), or if the applicable implementation 
plan (or implementation plan submission) includes any of these 
pollutants in the approved (or adequate) budget as part of the RFP, 
attainment, or maintenance strategy.\210\ Additionally, as the EPA 
explained in its May 6, 2005 transportation conformity rule amendments 
for the PM2.5 NAAQS, it is not necessary for a SIP to 
explicitly state that VOC, SO2, and/or ammonia are 
insignificant precursors. Instead, states should consider the on-road 
contribution of all four precursors to the PM2.5 problem as 
they develop their SIPs and establish emissions budgets for those 
precursors for which on-road emissions need to be addressed in order to 
attain the PM2.5 standard as expeditiously as practicable. 
Conformity determinations must address all precursors for which the SIP 
establishes a budget and need not address those precursors for which 
the state has not established a budget because the emissions of that 
precursor are insignificant.\211\
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    \210\ 40 CFR 93.102(b)(3), 93.102(b)(2)(v), and 93.122(f); see 
also Conformity Rule preambles at 69 FR 40004, 40031-40036 (July 1, 
2004), 70 FR 24280, 24283-24285 (May 6, 2005) and 70 FR 31354 (June 
1, 2005).
    \211\ 70 FR 24280, 24287 (May 6, 2005).
---------------------------------------------------------------------------

    By contrast, transportation conformity requirements apply with 
respect to emissions of NOX unless both the EPA Regional 
Administrator and the director of the state air agency have made a 
finding that transportation-related emissions of NOX within 
the nonattainment area are not a significant contributor to the 
PM2.5 nonattainment problem and have so notified the MPO and 
DOT, or the applicable implementation plan (or implementation plan 
submission) does not establish an approved (or adequate) budget for 
such emissions as part of the RFP, attainment, or maintenance 
strategy.\212\
---------------------------------------------------------------------------

    \212\ 40 CFR 93.102(b)(2)(iv).
---------------------------------------------------------------------------

    The criteria for insignificance determinations are provided in 40 
CFR 93.109(f). In order for a pollutant or precursor to be considered 
an insignificant contributor, the control strategy SIP must demonstrate 
that it would be unreasonable to expect that such an area would 
experience enough motor vehicle emissions growth in that pollutant/
precursor for a NAAQS violation to occur. Insignificance determinations 
are based on factors such as air quality, SIP motor vehicle control 
measures, trends and projections of motor vehicle emissions, and the 
percentage of the total SIP inventory that is comprised of motor 
vehicle emissions. The EPA's rationale for providing for insignificance 
determinations is described in the July 1, 2004 revision to the 
Transportation Conformity Rule.\213\
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    \213\ 69 FR 40004 (July 1, 2004).
---------------------------------------------------------------------------

    The EPA's process for determining the adequacy of a budget consists 
of three basic steps: (1) Notifying the public of a SIP submittal; (2) 
providing the public the opportunity to comment on the budget during a 
public comment period; and, (3) making a finding of adequacy or 
inadequacy. The EPA can notify the public by either posting an 
announcement that the EPA has received SIP budgets on the EPA's 
adequacy website (40 CFR 93.118(f)(1)), or through a Federal Register 
notice of proposed rulemaking when the EPA reviews the adequacy of an 
implementation plan budget simultaneously with its review and action on 
the SIP itself (40 CFR 93.118(f)(2)).
    For budgets to be approvable, they must meet, at a minimum, the 
EPA's adequacy criteria (40 CFR 93.118(e)(4)). To meet these 
requirements, the budgets must be consistent with the attainment and 
RFP requirements and reflect all of the motor vehicle control measures 
contained in the attainment and RFP demonstrations.\214\
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    \214\ 40 CFR 93.118(e)(4)(iii), (iv) and (v). For more 
information on the transportation conformity requirements and 
applicable policies on MVEBs, please visit our transportation 
conformity website at: http://www.epa.gov/otaq/stateresources/transconf/index.htm.
---------------------------------------------------------------------------

2. Motor Vehicle Emissions Budgets in the 2016 PM2.5 Plan
    The 2016 PM2.5 Plan includes budgets for direct 
PM2.5, NOx, and VOC for 2019 and 2022 (RFP milestone year 
and post-attainment quantitative milestone year, respectively).\215\ 
The budgets were calculated using EMFAC2014, the latest approved 
version of the EMFAC model for estimating emissions from on-road 
vehicles operating in California that was available at the time the 
plan was prepared, and SCAG's latest modeled VMT and speed 
distributions from the ``2016 Regional Transportation Plan/Sustainable 
Communities Strategy (RTP/SCS)'' adopted in April 2016.\216\ The 
budgets reflect annual average emissions because those emissions are 
linked with the District's RFP demonstration for the 2012 
PM2.5 NAAQS.
---------------------------------------------------------------------------

    \215\ 2016 PM2.5 Plan, Appendix VI-D and Table VI-D-
3.
    \216\ See footnote 30, supra.
---------------------------------------------------------------------------

    The direct PM2.5 budgets include tailpipe, brake wear, 
and tire wear emissions as well as paved road dust, unpaved road dust, 
and road construction dust emissions.\217\ The Plan includes budgets 
for NOx and VOC because they are regulated precursors under the Plan, 
but the Plan does not include budgets for SO2 or ammonia. 
The budgets included in the 2016 PM2.5 Plan are shown in 
Table 8.
---------------------------------------------------------------------------

    \217\ 2016 PM2.5 Plan, Table VI-D-3.

                         Table 8--MVEBs for the South Coast for the 2012 PM2.5 Standard
                                              [Annual average tpd]
----------------------------------------------------------------------------------------------------------------
                                               2019  (RFP year)                 2022  (post attainment year)
                                   -----------------------------------------------------------------------------
                                       PM2.5         NOX          VOC         PM2.5         NOX          VOC
----------------------------------------------------------------------------------------------------------------
Baseline emissions: Exhaust, brake        10.82       168.13        82.52        10.25       126.26        68.22
 and tire wear....................
Paved road dust...................         8.15  ...........  ...........         8.38  ...........  ...........
Unpaved road dust.................         0.59  ...........  ...........         0.59  ...........  ...........
Road construction.................         0.25  ...........  ...........         0.27  ...........  ...........
                                   -----------------------------------------------------------------------------
    Total.........................        19.81       168.13        82.52        19.48       126.26        68.22

[[Page 40052]]

 
Conformity budget.................           20          169           83           20          127           69
----------------------------------------------------------------------------------------------------------------
Source: 2016 PM2.5 Plan, Table VI-D-3. Budgets are rounded up to the nearest whole number.

    In the submittal letter for the 2016 PM2.5 Plan, CARB 
requested that we limit the duration of our approval of the budgets to 
the period before the effective date of the EPA's adequacy finding for 
any subsequently submitted budgets.\218\
---------------------------------------------------------------------------

    \218\ Letter dated April 27, 2017, from Richard W. Corey, 
Executive Officer, CARB, to Alexis Strauss, Acting Regional 
Administrator, EPA Region IX, 3.
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3. The EPA's Evaluation and Proposed Action
    We have evaluated the budgets in the 2016 PM2.5 Plan 
against our adequacy criteria in 40 CFR 93.118(e)(4) as part of our 
review of the budgets' approvability (see Table 10 in section IV of the 
EPA's TSD for this proposal) and will complete the adequacy review 
concurrent with our final action on the 2016 PM2.5 Plan. The 
EPA is not required under its transportation conformity rule to find 
budgets adequate prior to proposing approval of them.\219\
---------------------------------------------------------------------------

    \219\ Under the Transportation Conformity regulations, the EPA 
may review the adequacy of submitted MVEBs simultaneously with the 
EPA's approval or disapproval of the submitted implementation plan. 
40 CFR 93.118(f)(2).
---------------------------------------------------------------------------

    Based on the information about SO2 and ammonia emissions 
in the 2016 PM2.5 Plan, we propose to find that it is not 
necessary to establish MVEBs for transportation-related emissions of 
SO2 and ammonia to attain the 2012 PM2.5 standard 
in the South Coast. As discussed in the May 6, 2005 final 
transportation conformity rule that addresses the requirements for 
PM2.5 precursors,\220\ on-road emissions of SO2 
and ammonia typically are a small portion of the total emissions for 
these precursors. In the May 6, 2005 final rule, the EPA stated that 
with adopted fuel regulations, projections of on-road emissions of 
SO2 would be less than one percent of total SO2 
emissions in 2020. This was based on an analysis of projected on-road 
SO2 emissions in 372 counties that potentially could have 
been designated as nonattainment for the 1997 annual PM2.5 
NAAQS based on 1999-2001 air quality data.\221\ In the South Coast, on-
road emissions of SO2 and ammonia are projected to account 
for approximately 10 and 18 percent of total SO2 and ammonia 
emissions, respectively, in 2020.\222\ The projected contribution of 
total SO2 emissions to PM2.5 concentrations in 
the South Coast is in the range of 10 to 13 percent, and the projected 
contribution of total ammonia emissions to PM2.5 
concentrations in the area is in the range of 6 to 8 percent, in 
2021.\223\ CARB implements stringent standards for sulfur content in 
reformulated gasoline and diesel fuel,\224\ both of which effectively 
limit the SO2 contribution from motor vehicles in the South 
Coast. Given that transportation-related emissions of SO2 or 
ammonia are not significant contributors to the nonattainment problem 
in this area, it is not necessary for the 2016 PM2.5 Plan to 
include SO2 or ammonia budgets.
---------------------------------------------------------------------------

    \220\ 70 FR 24280, 24283-24285.
    \221\ Id. at 24283.
    \222\ 2016 PM2.5 Plan, Appendix III, Attachment A 
(identifying 2020 total SOX emissions estimate of 16.67 
tpd in the South Coast, of which 1.75 tpd (approximately 10 percent) 
is attributed to on-road motor vehicles, and 2020 total ammonia 
emissions estimate of 73.25 tpd, of which 13.21 tpd (approximately 
18 percent) is attributed to on-road motor vehicles).
    \223\ Id., Table V-6-6 (identifying projected 2021 
PM2.5 annual design values by component species, 
including SO4 and NH4).
    \224\ California Code of Regulations, title 13, sections 2262 
and 2282, 74 FR 33196, 33199 (July 10, 2009) (noting that CARB's 
sulfur content standard for diesel fuel is more stringent than the 
requirements of the federal ultra-low sulfur diesel program at 40 
CFR 80.29), and 75 FR 26653 (May 12, 2010) (final rule approving 
revisions to the California reformulated gasoline and diesel fuel 
regulations).
---------------------------------------------------------------------------

    For the reasons discussed in section V.F of this proposed rule, we 
are proposing to approve the State's demonstration that it is 
impracticable to attain the 2012 PM2.5 standard in the South 
Coast by the applicable Moderate area attainment date of December 31, 
2021 and are proposing to reclassify the area as Serious. Because the 
2016 PM2.5 Plan does not demonstrate attainment, we do not 
address in this proposal any budgets for the Moderate area attainment 
year of 2021.
    For the reasons discussed in section V.G of this proposed rule, we 
are proposing to approve the RFP demonstration in the 2016 
PM2.5 Plan. The 2019 and 2022 budgets, as shown in Table 8 
of this proposed rule, are consistent with applicable requirements for 
RFP, are clearly identified and precisely quantified, and meet all 
other applicable statutory and regulatory requirements including the 
adequacy criteria in 93.118(e)(4) and (5). For these reasons, the EPA 
proposes to approve the budgets listed in Table 8. We provide a more 
detailed discussion in section IV of the TSD, which can be found in the 
docket for today's action.
    We have previously approved MVEBs for the 1997 and 2006 annual and 
24-hour PM2.5 NAAQS.\225\ The budgets that the EPA is 
proposing to approve apply only for purposes of the 2012 
PM2.5 NAAQS and would not affect the status of the 
previously-approved budgets for the 1997 or 2006 PM2.5 NAAQS 
and related trading mechanisms, which remain in effect for those 
PM2.5 NAAQS.
---------------------------------------------------------------------------

    \225\ 76 FR 69928, 69951 (November 9, 2011) and 84 FR 3305, 3307 
(February 12, 2019).
---------------------------------------------------------------------------

    In general, only budgets in approved SIPs can be used for 
transportation conformity purposes. However, section 93.118(e) of the 
transportation conformity rule allows budgets in a SIP submission to 
apply for conformity purposes before the SIP submission is approved 
under certain circumstances. First, there must not be any other 
approved SIP budgets that have been established for the same year, 
pollutant, and CAA requirement. Second, the EPA must find that the 
submitted SIP budgets are adequate for transportation conformity 
purposes. To be found adequate, the submission must meet the conformity 
adequacy requirements of 40 CFR 93.118(e)(4) and (5).
    The transportation conformity rule allows for replacement of 
previously approved budgets by submitted MVEBs that the EPA has found 
adequate, if the EPA has limited the duration of its prior approval to 
the period before it finds replacement budgets adequate.\226\ However, 
the EPA will consider a state's request to limit the duration of an 
MVEB approval only if the request includes the following elements:
---------------------------------------------------------------------------

    \226\ 40 CFR 93.118(e)(1).
---------------------------------------------------------------------------

     An acknowledgement and explanation as to why the budgets 
under

[[Page 40053]]

consideration have become outdated or deficient;
     A commitment to update the budgets as part of a 
comprehensive SIP update; and
     A request that the EPA limit the duration of its approval 
to the period before the EPA finds new budgets to be adequate for 
transportation conformity purposes.\227\
---------------------------------------------------------------------------

    \227\ See, e.g., 67 FR 69139 (November 15, 2002), limiting our 
prior approval of MVEBs in certain California SIPs.
---------------------------------------------------------------------------

    In the submittal letter for the 2016 PM2.5 Plan, CARB 
requested that we limit the duration of our approval of the budgets to 
the period before the effective date of the EPA's adequacy finding for 
any subsequently submitted budgets.\228\ In a letter dated March 3, 
2020, CARB clarified their request to limit the budgets and included an 
explanation as to why the budgets under consideration will become 
outdated. In short, CARB has requested that we limit the duration of 
the approval of the budgets because the EPA's approval of EMFAC2017 
\229\ on August 15, 2019 has rendered the budgets outdated. CARB 
explains that the budgets from the 2016 PM2.5 Plan, for 
which we are proposing approval in today's action, will need to be 
revised using EMFAC2017 within the transportation conformity grace 
period established in our approval of EMFAC2017 to provide for a new 
conformity determination for the South Coast regional transportation 
plan and program. In addition, CARB states that, without the ability to 
replace the budgets using the budget adequacy process, the benefits of 
using the updated data may not be realized for a year or more after the 
updated SIP (with the EMFAC2017-derived budgets) is submitted, due to 
the length of the SIP approval process. We find that CARB's explanation 
for limiting the duration of the approval of the budgets is appropriate 
and provides us with a reasonable basis on which to limit the duration 
of the approval of the budgets.
---------------------------------------------------------------------------

    \228\ See letter dated April 27, 2017, from Richard W. Corey, 
Executive Officer, CARB, to Alexis Strauss, Acting Regional 
Administrator, EPA Region IX, 3.
    \229\ EMFAC2017 updates vehicle mix and emissions data of the 
previously approved version of the model, EMFAC2014.
---------------------------------------------------------------------------

    We note that CARB has not committed to update the budgets as part 
of a comprehensive SIP update, but as a practical matter, CARB must 
submit a SIP revision that includes updated demonstrations as well as 
the updated budgets to meet the adequacy criteria in 40 CFR 
93.118(e)(4); \230\ and thus, we do not need a specific commitment for 
such a plan at this time. For the reasons provided above, and in light 
of CARB's explanation for why the budgets will become outdated and 
should be replaced upon an adequacy finding for updated budgets, we 
propose to limit the duration of our approval of the budgets in the 
2016 PM2.5 Plan until new budgets have been found adequate.
---------------------------------------------------------------------------

    \230\ Under 40 CFR 93.118(e)(4), the EPA will not find a budget 
in a submitted SIP to be adequate unless, among other criteria, the 
budgets, when considered together with all other emission sources, 
are consistent with applicable requirements for RFP and attainment. 
40 CFR 93.118(e)(4)(iv).
---------------------------------------------------------------------------

VI. Reclassification as Serious Nonattainment and Serious Area SIP 
Requirements

A. Reclassification as Serious and Applicable Attainment Date

    Section 188 of the Act outlines the process for classification of 
PM2.5 nonattainment areas and establishes the applicable 
attainment dates. Under the plain meaning of the terms of section 
188(b)(1) of the Act, the EPA has general authority to reclassify at 
any time before the applicable attainment date any area that the EPA 
determines cannot practicably attain the standard by such date. 
Accordingly, section 188(b)(1) of the Act is a general expression of 
delegated rulemaking authority. In addition, subparagraphs (A) and (B) 
of section 188(b)(1) mandate that the EPA reclassify ``appropriate'' 
PM10 nonattainment areas at specified time frames (i.e., by 
December 31, 1991 for the initial PM10 nonattainment areas, 
and within 18 months after the SIP submittal due date for subsequent 
nonattainment areas). These subparagraphs do not restrict the EPA's 
general authority but simply specify that, at a minimum, it must be 
exercised at certain times.\231\
---------------------------------------------------------------------------

    \231\ For a general discussion of the EPA's interpretation of 
the reclassification provisions in section 188(b)(1) of the Act, see 
the General Preamble, 13537-13538.
---------------------------------------------------------------------------

    We have reviewed the air quality modeling and impracticability 
demonstration in the 2016 PM2.5 Plan and, based on our 
review, agree with the District's conclusion that implementation of the 
State/District's SIP control strategy, including RACM/RACT and 
additional reasonable measures, is insufficient to bring the South 
Coast into attainment by the December 31, 2021 Moderate area attainment 
deadline. See sections V.C and V.F of this notice. In addition, we have 
reviewed recent PM2.5 monitoring data for the South Coast 
available in the EPA's Air Quality System (AQS) database. These data 
show that 24-hour PM2.5 levels in the South Coast continue 
to be above 12 [micro]g/m\3\, the level of the 2012 PM2.5 
standard, and the recent trends in the South Coast's annual 
PM2.5 levels are not consistent with a projection of 
attainment by the end of 2021.\232\
---------------------------------------------------------------------------

    \232\ EPA, Design Value Spreadsheets, 
``20200306_SouthCoastPM25Annual.xlsx'' and 
``pm25_designvalues_20162018_final_12_03_19.xlsx.''
---------------------------------------------------------------------------

    In accordance with section 188(b)(1) of the Act, the EPA is 
proposing to reclassify the South Coast area from Moderate to Serious 
nonattainment for the 2012 PM2.5 standard of 12 [micro]g/
m\3\, based on the EPA's determination that the South Coast area cannot 
practicably attain the standard by the applicable attainment date of 
December 31, 2021.
    Under section 188(c)(2) of the Act, the attainment date for a 
Serious area ``shall be as expeditiously as practicable but no later 
than the end of the tenth calendar year beginning after the area's 
designation as nonattainment . . .'' The EPA designated the South Coast 
area as nonattainment for the 2012 PM2.5 standard effective 
April 15, 2015.\233\ Therefore, upon final reclassification of the 
South Coast area as a Serious nonattainment area, the latest 
permissible attainment date under section 188(c)(2) of the Act, for 
purposes of the 2012 PM2.5 standard in this area, will be 
December 31, 2025.
---------------------------------------------------------------------------

    \233\ 80 FR 2206.
---------------------------------------------------------------------------

    Under section 188(e) of the Act, a state may apply to the EPA for a 
single extension of the Serious area attainment date by up to 5 years, 
which the EPA may grant if the state satisfies certain conditions. 
Before the EPA may extend the attainment date for a Serious area under 
section 188(e), the state must: (1) Apply for an extension of the 
attainment date beyond the statutory attainment date; (2) demonstrate 
that attainment by the statutory attainment date is impracticable; (3) 
demonstrate that it has complied with all requirements and commitments 
pertaining to the area in the implementation plan; (4) demonstrate to 
the satisfaction of the Administrator that the plan for the area 
includes the most stringent measures that are included in the 
implementation plan of any state or are achieved in practice in any 
state, and can feasibly be implemented in the area; and (5) submit a 
demonstration of attainment by the most expeditious alternative date 
practicable.\234\
---------------------------------------------------------------------------

    \234\ For a discussion of the EPA's interpretation of the 
requirements of section 188(e), see Addendum, 42002; 65 FR 19964 
(April 13, 2000) (proposed action on PM10 Plan for 
Maricopa County, Arizona); 67 FR 48718 (July 25, 2002) (final action 
on PM10 Plan for Maricopa County, Arizona); and Vigil v. 
EPA, 366 F.3d 1025, amended at 381 F.3d 826 (9th Cir. 2004) 
(remanding EPA action on PM10 Plan for Maricopa County, 
Arizona but generally upholding the EPA's interpretation of CAA 
section 188(e)).

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[[Page 40054]]

B. Clean Air Act Requirements for Serious PM2.5 Nonattainment Area 
Plans

    Upon reclassification as a Serious nonattainment area for the 2012 
PM2.5 NAAQS, California will be required to submit 
additional SIP revisions to satisfy the statutory requirements that 
apply to Serious PM2.5 nonattainment areas, including the 
requirements of subpart 4 of part D, title I of the Act.
    The Serious area SIP elements that California will be required to 
submit are as follows:
    1. Provisions to assure that the best available control measures 
(BACM),\235\ including best available control technology (BACT) for 
stationary sources, for the control of direct PM2.5 and 
PM2.5 precursors shall be implemented no later than 4 years 
after the area is reclassified (CAA section 189(b)(1)(B));
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    \235\ The EPA defines BACM as, among other things, the maximum 
degree of emission reduction achievable for a source or source 
category, which is determined on a case-by-case basis considering 
energy, environmental, and economic impacts. (Addendum, 42010 and 
42014). BACM must be implemented for all categories of sources in a 
Serious PM2.5 nonattainment area unless the State 
adequately demonstrates that a particular source category does not 
contribute significantly to nonattainment of the PM2.5 
standard. (Id. at 42011, 42012).
---------------------------------------------------------------------------

    2. a demonstration (including air quality modeling) that the plan 
provides for attainment as expeditiously as practicable but no later 
than December 31, 2025, or where the state is seeking an extension of 
the attainment date under section 188(e), a demonstration that 
attainment by December 31, 2025 is impracticable and that the plan 
provides for attainment by the most expeditious alternative date 
practicable and no later than December 31, 2030 (CAA sections 
189(b)(1)(A), 188(c)(2), and 188(e));
    3. plan provisions that require reasonable further progress (RFP) 
(CAA 172(c)(2));
    4. 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));
    5. provisions to assure that control requirements applicable to 
major stationary sources of PM2.5 also apply to major 
stationary sources of PM2.5 precursors, except where the 
state demonstrates to the EPA's satisfaction that such sources do not 
contribute significantly to PM2.5 levels that exceed the 
standard in the area (CAA section 189(e));
    6. a comprehensive, accurate, current inventory of actual emissions 
from all sources of PM2.5 and PM2.5 precursors in 
the area (CAA section 172(c)(3));
    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 NNSR program to lower the applicable ``major 
stationary source'' \236\ thresholds from 100 tpy to 70 tpy (CAA 
section 189(b)(3)) and to satisfy the subpart 4 control requirements 
for major stationary sources of PM2.5 precursors (CAA 
section 189(e)).
---------------------------------------------------------------------------

    \236\ 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 tpy of PM10 (CAA 
sections 189(b)(3)).
---------------------------------------------------------------------------

    As discussed in section V.E of this proposed rule, California 
submitted NNSR SIP revisions for the South Coast to address the subpart 
4 NNSR requirements for Serious PM2.5 nonattainment areas on 
May 8, 2017, and the EPA conditionally approved these NNSR SIP 
revisions on November 30, 2018.\237\ The State fulfilled the commitment 
that provided the basis for the EPA's conditional approval of these 
NNSR SIP revisions by submitting a revised version of Rule 1325 
(``Federal PM2.5 New Source Review Program'') on April 24, 
2019.
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    \237\ 83 FR 61551 (establishing December 30, 2019 deadline for 
the State to correct identified rule deficiencies). Previously, the 
EPA fully approved NNSR SIP revisions from California to address the 
NNSR requirements for Moderate PM2.5 nonattainment areas. 
80 FR 24821 (May 1, 2015).
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    Finally, reclassification of the South Coast area as Serious 
nonattainment for the 2012 PM2.5 standard would lower the de 
minimis threshold under the CAA's General Conformity requirements (40 
CFR part 93, subpart B) from 100 tpy to 70 tpy for PM2.5 and 
PM2.5 precursors.\238\ In this case, however, 
reclassification would have no impact on the applicable General 
Conformity de minimis thresholds, because the South Coast area is 
already subject to the 70 tpy de minimis threshold for PM2.5 
and all PM2.5 precursors as a result of the EPA's previous 
action reclassifying the area as Serious nonattainment for the 2006 
PM2.5 NAAQS.\239\
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    \238\ 40 CFR 93.153(b), 81 FR 58010, 58126.
    \239\ 81 FR 1514.
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C. Statutory Deadline for Submittal of the Serious Area Plan

    For an area reclassified as a Serious nonattainment area before the 
applicable attainment date under CAA section 188(b)(1), section 
189(b)(2) requires the state to submit the required BACM provisions 
``no later than 18 months after reclassification of the area as a 
Serious Area'' and to submit the required attainment demonstration ``no 
later than 4 years after reclassification of the area to Serious.'' 
Section 189(b)(2) establishes outer bounds on the SIP submission 
deadlines as necessary or appropriate to assure consistency among the 
required submissions and to implement the statutory requirements.
    The Act provides the state with up to 18 months after final 
reclassification of an area to Serious to submit the required BACM 
provisions. Because an up-to-date emissions inventory serves as the 
foundation for a state's BACM/BACT determination, the PM2.5 
SIP Requirements Rule requires the state to submit the emissions 
inventory required under CAA section 172(c)(3) within 18 months after 
the effective date of final reclassification.\240\ Similarly, because 
an effective evaluation of BACM/BACT measures requires evaluation of 
the precursor pollutants that must be controlled to provide for 
expeditious attainment in the area, if the state chooses to submit an 
optional precursor insignificance demonstration to support a 
determination to exclude a PM2.5 precursor from the required 
control measure evaluations for the area, the EPA requires that the 
state submit any such demonstration by this same date. An 18-month 
timeframe for submission of these plan elements is consistent with both 
the timeframe for submission of BACM/BACT provisions under CAA section 
189(b)(2) and the timeframe for submission of subpart 1 plan elements 
under section 172(b) of the Act.\241\
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    \240\ 81 FR 58010, 58077.
    \241\ Section 172(b) requires the EPA to establish, concurrent 
with nonattainment area designations, a schedule extending no later 
than 3 years from the date of the nonattainment designation for 
states to submit plans or plan revisions meeting the applicable 
requirements of sections 110(a)(2) and 172(c) of the CAA.
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    The PM2.5 SIP Requirements Rule also establishes a 
specific deadline for submission of the attainment demonstration and 
attainment-related plan elements following discretionary 
reclassification, which is the earlier of (1) four years from the date 
of reclassification, or (2) the end of the eighth calendar year after 
designation.\242\ In this case, the earlier of these two dates will be 
the end of the eighth calendar year after designation--i.e., December 
31, 2023. The attainment-related plan elements required within the same 
timeframe as the attainment demonstration are: (1) The RFP 
demonstration required under section 172(c)(2); (2) the quantitative 
milestones

[[Page 40055]]

required under section 189(c); (3) any additional control measures 
necessary to meet the requirements of section 172(c)(6); and (4) the 
contingency measures required under section 172(c)(9). Although section 
189(b)(2) generally provides for up to four years after a discretionary 
reclassification for the state to submit the required attainment 
demonstration, given the timing of this reclassification action less 
than two years before the Moderate area attainment date, it is 
appropriate in this case for the EPA to establish an earlier SIP 
submission deadline to assure timely implementation of the statutory 
requirements.
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    \242\ 81 FR 58010, 58077.
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    Finally, the PM2.5 SIP Requirements Rule establishes a 
regulatory requirement that the state submit revised NNSR program 
requirements no later than 18 months after final reclassification.\243\ 
The Act does not specify a deadline for the state's submission of SIP 
revisions to meet NNSR program requirements to lower the ``major 
stationary source'' threshold from 100 tpy to 70 tpy (CAA section 
189(b)(3)) and to address the control requirements for major stationary 
sources of PM2.5 precursors (CAA section 189(e)) \244\ 
following reclassification of a Moderate PM2.5 nonattainment 
area as Serious nonattainment under subpart 4. Pursuant to the EPA's 
gap-filling authority in CAA section 301(a) and to effectuate the 
statutory control requirements in section 189 of the Act, the 
PM2.5 SIP Requirements Rule requires the state to submit 
these NNSR SIP revisions, as well as any necessary analysis of and 
additional control requirements for major stationary sources of 
PM2.5 precursors, no later than 18 months after the 
effective date of final reclassification of the South Coast area as 
Serious nonattainment for the 2012 PM2.5 standard. This due 
date will ensure that necessary control requirements for major sources 
are established in advance of the required attainment demonstration. An 
18-month timeframe for submission of the NNSR SIP revisions also aligns 
with the statutory deadline for submission of BACM and BACT provisions 
and the broader analysis of PM2.5 precursors for potential 
controls on existing sources in the area.
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    \243\ Id. at 58078.
    \244\ Section 189(e) requires that the control requirements 
applicable to major stationary sources of PM2.5 also 
apply to major stationary sources of PM2.5 precursors, 
except where the state demonstrates to the EPA's satisfaction that 
such sources do not contribute significantly to PM2.5 
levels that exceed the standard in the area.
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    Accordingly, if we finalize our proposal to reclassify the South 
Coast as a Serious nonattainment area for the 2012 PM2.5 
NAAQS, California will be required to submit the emissions inventory 
required under CAA section 172(c)(3), the BACM/BACT provisions required 
under CAA section 189(b)(1)(B), and any NNSR SIP revisions required to 
satisfy the requirements of CAA sections 189(b)(3) and 189(e) for the 
2012 PM2.5 NAAQS no later than 18 months after the effective 
date of a final reclassification action. Additionally, California will 
be required to submit the Serious area attainment demonstration and all 
attainment-related plan elements no later than the end of the eighth 
calendar year after designation--i.e., by December 31, 2023. We note 
that the 2016 PM2.5 Plan submitted on April 27, 2017, 
includes a Serious area attainment demonstration, an emissions 
inventory, attainment-related plan elements, and BACM/BACT provisions, 
which the EPA intends to evaluate and act on through subsequent 
rulemakings, as appropriate.

VII. Reclassification of Areas of Indian Country

    When the South Coast area was designated nonattainment for the 2012 
PM2.5 NAAQS, five Indian tribes were located within the 
boundaries of the nonattainment area. These tribes include the Cahuilla 
Band of Mission Indians of the Cahuilla Reservation, the Morongo Band 
of Mission Indians, the Ramona Band of Cahuilla, the San Manuel Band of 
Mission Indians, and the Soboba Band of Luiseno Indians. At that time, 
the main body of land belonging to the Pechanga Band of Luiseno Mission 
Indians of the Pechanga Reservation was expressly excluded from the 
South Coast 2012 PM2.5 nonattainment area. However, since 
designations, the tribe acquired the Meadowbrook parcel, which is 
located approximately 30 miles northwest of the northern boundary of 
the Reservation and is located within the 2012 PM2.5 
nonattainment area.
    We have considered the relevance of our proposal to reclassify the 
South Coast area as Serious nonattainment for the 2012 PM2.5 
standard for each tribe located within the South Coast area. We believe 
that the same facts and circumstances that support the proposal for the 
non-Indian country lands also support the proposal for reservation 
areas of Indian country \245\ and any other areas of Indian country 
where the EPA or a tribe has demonstrated that the tribe has 
jurisdiction located within the South Coast nonattainment area. The EPA 
is therefore proposing to exercise our authority under CAA section 
188(b)(1) to reclassify areas of Indian country geographically located 
in the South Coast nonattainment area. Section 188(b)(1) broadly 
authorizes the EPA to reclassify a nonattainment area--including any 
Indian country located within such an area--that the EPA determines 
cannot practicably attain the relevant standard by the applicable 
attainment date.
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    \245\ ``Indian country'' as defined at 18 U.S.C. 1151 refers to: 
``(a) all land within the limits of any Indian reservation under the 
jurisdiction of the United States Government, notwithstanding the 
issuance of any patent, and including rights-of-way running through 
the reservation, (b) all dependent Indian communities within the 
borders of the United States whether within the original or 
subsequently acquired territory thereof, and whether within or 
without the limits of a state, and (c) all Indian allotments, the 
Indian titles to which have not been extinguished, including rights-
of-way running through the same.''
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    Directly-emitted PM2.5 and its precursor pollutants 
(NOX, SO2, VOC, and ammonia) are emitted 
throughout a nonattainment area and can be transported throughout that 
nonattainment area. Therefore, boundaries for nonattainment areas are 
drawn to encompass both areas with direct sources of the pollutant 
problem as well as nearby areas in the same airshed. Initial 
classifications of nonattainment areas are coterminous with, that is, 
they match exactly, their boundaries. The EPA believes this approach 
best ensures public health protection from the adverse effects of 
PM2.5 pollution. Therefore, it is generally 
counterproductive from an air quality and planning perspective to have 
a disparate classification for a land area located within the 
boundaries of a nonattainment area, such as the reservation areas of 
Indian country contained within the South Coast PM2.5 
nonattainment area. Violations of the 2012 PM2.5 standard, 
which are measured and modeled throughout the nonattainment area, as 
well as shared meteorological conditions, would dictate the same 
conclusion. Furthermore, emissions increases in portions of a 
PM2.5 nonattainment area that are left classified as 
Moderate could counteract the effects of efforts to attain the standard 
within the overall area because less stringent requirements would apply 
in those Moderate portions relative to those that would apply in the 
portions of the area reclassified to Serious.
    Uniformity of classification throughout a nonattainment area is 
thus a guiding principle and premise when an area is being 
reclassified. In this

[[Page 40056]]

particular case, we are proposing to determine, based on the State's 
demonstration and current ambient air quality trends, that the entire 
South Coast nonattainment area, including all reservations areas of 
Indian country and any other area located within the South Coast where 
a tribe has jurisdiction, cannot practicably attain the 2012 
PM2.5 standard by the applicable Moderate area attainment 
date of December 31, 2021.
    In light of the considerations outlined above that support 
retention of a uniformly-classified PM2.5 nonattainment 
area, and our proposal to find that it is impracticable for the area to 
attain by the applicable attainment date, we propose to reclassify the 
entire South Coast nonattainment area, including reservation areas of 
Indian country and any other area of Indian country located within it 
where the EPA or a tribe has demonstrated that the tribe has 
jurisdiction, as Serious nonattainment for the 2012 PM2.5 
standard.
    Generally, the effect of reclassification is to lower the 
applicable ``major source'' threshold for purposes of the NNSR program 
and the Title V operating permit program from 100 tpy to 70 tpy,\246\ 
thus subjecting more new or modified stationary sources to these 
requirements. Reclassification also lowers the de minimis threshold 
under the CAA's General Conformity requirements from 100 tpy to 70 
tpy.\247\ In this case, however, reclassification would not change the 
``major source'' thresholds because, as a result of the EPA's January 
2016 reclassification of the South Coast area as a ``Serious'' 
nonattainment area for the 2006 PM2.5 NAAQS, the area is 
already subject to the 70 tpy major source threshold for Serious 
PM2.5 nonattainment areas in CAA section 189(b)(3).\248\ 
Likewise, reclassification would have no impact on the applicable 
General Conformity de minimis thresholds, because the South Coast area 
is already subject to the 70 tpy de minimis threshold for 
PM2.5 and all PM2.5 precursors as a result of the 
EPA's previous reclassification of the area as Serious for the 2006 
PM2.5 NAAQS.\249\
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    \246\ CAA sections 189(b)(3) and 501(2)(B).
    \247\ 40 CFR part 93, subpart B.
    \248\ 81 FR 1514.
    \249\ Id. and 40 CFR 93.153(b).
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    The EPA has contacted tribal officials to invite government-to-
government consultation on this rulemaking effort.\250\ The EPA 
specifically solicits additional comment on this proposed rule from 
tribal officials. We note that although eligible tribes may seek EPA 
approval of relevant tribal programs under the CAA, none of the 
affected tribes will be required to submit an implementation plan as a 
result of this reclassification.
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    \250\ We sent letters dated January 22, 2020 to tribal officials 
offering government-to-government consultation.
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VIII. Summary of Proposed Actions and Request for Public Comment

    Under CAA section 110(k)(3), the EPA is proposing to approve the 
following elements of the 2016 PM2.5 Plan submitted by 
California to address the CAA's Moderate area planning requirements for 
the 2012 PM2.5 NAAQS in the South Coast nonattainment area:
    1. The 2012 base year emissions inventories as meeting the 
requirements of CAA section 172(c)(3);
    2. the reasonably available control measures/reasonably available 
control technology demonstration as meeting the requirements of CAA 
sections 172(c)(1) and 189(a)(1)(C);
    3. the demonstration that attainment by the Moderate area 
attainment date of December 31, 2021 is impracticable as meeting the 
requirements of CAA section 189(a)(1)(B)(ii);
    4. the reasonable further progress demonstration as meeting the 
requirements of CAA section 172(c)(2);
    5. the quantitative milestones as meeting the requirements of CAA 
section 189(c);
    6. the motor vehicle emissions budgets for 2019 and 2022 as shown 
in Table 8 of this proposed rule because they are derived from an 
approvable RFP demonstration and meet the requirements of CAA section 
176(c) and 40 CFR part 93, subpart A; and
    7. the SCAQMD's commitments to adopt and implement specific rules 
and measures in accordance with the schedule provided in Chapter 4 of 
the 2016 PM2.5 Plan to achieve the emission reductions shown 
therein, and to submit these rules and measures to CARB for transmittal 
to the EPA as a revision to the SIP, as stated on page 9 of SCAQMD 
Governing Board Resolution 17-2.
    The EPA is also proposing to conditionally approve the contingency 
measure element of the 2016 PM2.5 Plan as meeting the 
requirements of CAA section 172(c)(9) for the 2006 PM2.5 
NAAQS and the 2012 PM2.5 NAAQS.
    Finally, pursuant to CAA section 188(b)(1), the EPA is proposing to 
reclassify the South Coast PM2.5 nonattainment area, 
including reservation areas of Indian country and any other area where 
the EPA or a tribe has demonstrated that a tribe has jurisdiction 
within the South Coast area, as Serious nonattainment for the 2012 
PM2.5 standard based on the agency's determination that the 
South Coast area cannot practicably attain the standard by the Moderate 
area attainment date of December 31, 2021. Upon final reclassification 
as a Serious area, California will be required to submit, within 18 
months after the effective date of the reclassification, provisions to 
assure that BACM shall be implemented no later than 4 years after the 
date of reclassification. California will also be required to submit, 
by December 31, 2023, a Serious area plan that satisfies the 
requirements of part D of title I of the Act. This plan must include a 
demonstration that the South Coast area will attain the 2012 
PM2.5 standard as expeditiously as practicable but no later 
than December 31, 2025, or by the most expeditious alternative date 
practicable and no later than December 31, 2030, in accordance with the 
requirements of CAA sections 189(b) and 188(e).
    We note that the 2016 PM2.5 Plan submitted on April 27, 
2017, includes a Serious area attainment demonstration, an emissions 
inventory, attainment-related plan elements, and BACM/BACT provisions, 
which the EPA intends to evaluate and act on through subsequent 
rulemakings, as appropriate.
    In addition, because the EPA is proposing to similarly reclassify 
reservation areas of Indian country and any other area of Indian 
country where the EPA or a tribe has demonstrated that the tribe has 
jurisdiction within the South Coast PM2.5 nonattainment area 
as Serious nonattainment for the 2012 PM2.5 standard, 
consistent with our proposed reclassification of the surrounding non-
Indian country lands, the EPA has invited consultation with interested 
tribes concerning this issue. Although eligible tribes may seek the 
EPA's approval of relevant tribal programs under the CAA, none of the 
affected tribes will be required to submit an implementation plan as a 
result of this reclassification.
    We will accept comments from the public on these proposals for the 
next 30 days. The deadline and instructions for submission of comments 
are provided in the DATES and ADDRESSES sections at the beginning of 
this preamble.

IX. Statutory and Executive Order Reviews

    Under the Clean Air Act, the Administrator is required to approve a 
SIP submission that complies with the provisions of the Act and 
applicable federal regulations. 42 U.S.C. 7410(k); 40 CFR 52.02(a). 
Thus, in reviewing SIP submissions, the EPA's role is to approve state 
choices, provided that they meet the criteria of the Clean Air

[[Page 40057]]

Act. Accordingly, this proposed action merely proposes to approve, or 
conditionally approve, state plans as meeting federal requirements and 
does not impose additional requirements beyond those imposed by state 
law. For that reason, this proposed action:
     Is not a ``significant regulatory action'' subject to 
review by the Office of Management and Budget under Executive Orders 
12866 (58 FR 51735, October 4, 1993) and 13563 (76 FR 3821, January 21, 
2011);
     Is not an Executive Order 13771 (82 FR 9339, February 2, 
2017) regulatory action because SIP approvals are exempted under 
Executive Order 12866;
     Does not impose an information collection burden under the 
provisions of the Paperwork Reduction Act (44 U.S.C. 3501 et seq.);
     Is certified as not having a significant economic impact 
on a substantial number of small entities under the Regulatory 
Flexibility Act (5 U.S.C. 601 et seq.);
     Does not contain any unfunded mandate or significantly or 
uniquely affect small governments, as described in the Unfunded 
Mandates Reform Act of 1995 (Pub. L. 104-4);
     Does not have Federalism implications as specified in 
Executive Order 13132 (64 FR 43255, August 10, 1999);
     Is not an economically significant regulatory action based 
on health or safety risks subject to Executive Order 13045 (62 FR 
19885, April 23, 1997);
     Is not a significant regulatory action subject to 
Executive Order 13211 (66 FR 28355, May 22, 2001);
     Is not subject to requirements of Section 12(d) of the 
National Technology Transfer and Advancement Act of 1995 (15 U.S.C. 272 
note) because application of those requirements would be inconsistent 
with the Clean Air Act; and
     Does not provide the EPA with the discretionary authority 
to address disproportionate human health or environmental effects with 
practical, appropriate, and legally permissible methods under Executive 
Order 12898 (59 FR 7629, February 16, 1994).
    In addition, the SIP is not approved to apply on any Indian 
reservation land or in any other area where the EPA or an Indian tribe 
has demonstrated that a tribe has jurisdiction. In those areas of 
Indian country, the proposed rule does not have tribal implications and 
will not impose substantial direct costs on tribal governments or 
preempt tribal law as specified by Executive Order 13175 (65 FR 67249, 
November 9, 2000).

List of Subjects

40 CFR Part 52

    Environmental protection, Air pollution control, Ammonia, 
Incorporation by reference, Intergovernmental relations, Nitrogen 
dioxide, Particulate matter, Reporting and recordkeeping requirements, 
Sulfur dioxide, Volatile organic compounds.

40 CFR Part 81

    Environmental protection, Air pollution control, Particulate 
matter.

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

     Dated: June 5, 2020.
John Busterud,
Regional Administrator, Region IX.
[FR Doc. 2020-12690 Filed 7-1-20; 8:45 am]
BILLING CODE 6560-50-P