[Federal Register Volume 85, Number 12 (Friday, January 17, 2020)]
[Proposed Rules]
[Pages 2949-2974]
[FR Doc No: 2020-00538]

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 52

[EPA-R09-OAR-2019-0241; FRL-10003-99-Region 9]

Approval of Air Quality Implementation Plans; California;
Coachella Valley; 2008 8-Hour Ozone Nonattainment Area Requirements

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, all or portions of two state
implementation plan (SIP) revisions submitted by the State of
California to meet Clean Air Act requirements for the 2008 8-hour ozone
national ambient air quality standards (NAAQS or ``standards'') in the
Coachella Valley ozone nonattainment area (``Coachella Valley''). The
two SIP revisions include the portions of the ``Final 2016 Air Quality
Management Plan'' and the ``2018 Updates to the California State
Implementation Plan'' that address ozone in the Coachella Valley. These
submittals address the nonattainment area requirements for the 2008 8-
hour ozone NAAQS, including the requirements for an emissions
inventory, emissions statements, attainment demonstration, reasonable
further progress (RFP), reasonably available control measures,
contingency measures, and motor vehicle emissions budgets. The EPA is
proposing to approve these submittals as meeting all the applicable
ozone nonattainment area requirements except for the contingency
measure requirements, for which the EPA is proposing to conditionally
approve the RFP contingency measures and to defer action on the
attainment contingency measure.

DATES: Any comments must be submitted by February 18, 2020.

ADDRESSES: Submit your comments, identified by Docket ID No. EPA-R09-
OAR-2019-0241 at https://www.regulations.gov. For comments submitted at
Regulations.gov, follow the online instructions for submitting
comments. Once submitted, comments cannot be edited or removed from
Regulations.gov. The EPA may publish any comment received to its public
docket. Do not submit electronically any information you consider to be
Confidential Business Information (CBI) or other information whose
disclosure is restricted by statute. Multimedia submissions (audio,
video, etc.) must be accompanied by a written comment.

The written comment is considered the official comment and should
include discussion of all points you wish to make. The EPA will
generally not consider comments or comment contents located outside of
the primary submission (i.e., on the web, cloud, or other file sharing
system). For additional submission methods, please contact the person
identified in the FOR FURTHER INFORMATION CONTACT section. For the full
EPA public comment policy, information about CBI or multimedia
submissions, and general guidance on making effective comments, please
visit http://www.epa.gov/dockets/commenting-epa-dockets.

FOR FURTHER INFORMATION CONTACT: John Ungvarsky, Air Planning Office
(AIR-2), EPA Region IX, 75 Hawthorne Street, San Francisco, CA 94105,
(415) 972-3963, or by email at<EMAIL_ADDRESS>
SUPPLEMENTARY INFORMATION:  Throughout this document, ``we,'' ``us''
and ``our'' refer to the EPA.

Table of Contents

I. Regulatory Context
    A. Ozone Standards, Area Designations and SIPs
    B. The Coachella Valley 2008 Ozone Nonattainment Area
    C. Clean Air Act and Regulatory Requirements for 2008 Ozone
Nonattainment Area SIPs
II. Submissions From the State of California To Address 2008 Ozone
Requirements in the Coachella Valley
    A. Summary of Submissions
    B. Clean Air Act Procedural Requirements for Adoption and
Submission of SIP Revisions
III. Review of the 2016 Coachella Valley Ozone SIP
    A. Emissions Inventories
    B. Emissions Statement
    C. Reasonably Available Control Measures Demonstration and
Control Strategy
    D. Attainment Demonstration
    E. Rate of Progress Plan and Reasonable Further Progress
Demonstration
    F. Transportation Control Strategies and Measures To Offset
Emissions Increases From Vehicle Miles Traveled
    G. Contingency Measures
    H. Motor Vehicle Emissions Budgets for Transportation Conformity
    I. Other Clean Air Act Requirements Applicable to Severe Ozone
Nonattainment Areas
IV. Proposed Action
V. Statutory and Executive Order Reviews

I. Regulatory Context

A. Ozone Standards, Area Designations and SIPs

    Ground-level ozone pollution is formed from the reaction of
volatile organic compounds (VOC) and oxides of nitrogen
(NOX) in the presence of sunlight.\1\ These two pollutants,
referred to as ozone precursors, are emitted by many types of sources,
including on- and off-road motor vehicles and engines, power plants and
industrial facilities, and smaller area sources such as lawn and garden
equipment and paints.
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    \1\ The State of California refers to reactive organic gases
(ROG) in some of its ozone-related SIP submissions. As a practical
matter, ROG and VOC refer to the same set of chemical constituents,
and for the sake of simplicity, we refer to this set of gases as VOC
in this proposed rule.
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    Scientific evidence indicates that adverse public health effects
occur following exposure to ozone, particularly in children and adults
with lung disease. Breathing air containing ozone can reduce lung
function and inflame airways, which can increase respiratory symptoms
and aggravate asthma or other lung diseases.\2\
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    \2\ ``Fact Sheet--2008 Final Revisions to the National Ambient
Air Quality Standards for Ozone,'' dated March 2008.
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    Under section 109 of the Clean Air Act (CAA or ``the Act''), the
EPA promulgates NAAQS for pervasive air pollutants, such as ozone. The
NAAQS are concentration levels that the attainment and maintenance of
which the EPA has determined to be requisite to protect public health
and welfare. Following promulgation of a new or revised NAAQS, the EPA
is required by the CAA to designate areas throughout the nation as
either attaining or not attaining the standards.
    On February 8, 1979, under section 109 of the CAA, the EPA
established primary and secondary NAAQS for ozone at 0.12 parts per
million (ppm) averaged over a 1-hour period.\3\ On July 18, 1997, the
EPA revised the primary and secondary standards for ozone to set the
acceptable level of ozone in the ambient air at 0.08 ppm averaged over
an 8-hour period (``1997 ozone NAAQS'').\4\
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    \3\ See 44 FR 8202.
    \4\ See 62 FR 38856. On April 30, 2004, the EPA designated and
classified areas of the country with respect to the 1997 ozone
NAAQS. See 69 FR 23858. On July 10, 2019, the EPA granted a request
from the State of California to reclassify the Coachella Valley
ozone nonattainment area from ``Severe-15'' to ``Extreme'' for the
1997 ozone NAAQS. See 84 FR 32841.
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    In 2008, the EPA lowered the 8-hour ozone NAAQS to 0.075 ppm
(``2008 ozone NAAQS'') to replace the 1997 ozone NAAQS of 0.08 ppm.\5\
In 2012, the EPA designated the Coachella Valley as nonattainment for
the 2008 ozone NAAQS and classified the area as ``Severe-15.'' \6\
Areas classified as Severe-15 must attain the NAAQS within 15 years of
the effective date of the nonattainment designation.\7\
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    \5\ 73 FR 16436 (March 27, 2008). The EPA further tightened the
8-hour ozone NAAQS to 0.070 ppm in 2015, but this proposed action
relates to the requirements for the 2008 ozone NAAQS. Information on
the 2015 ozone NAAQS is available at 80 FR 65292 (October 26, 2015).
    \6\ 77 FR 30088 (May 21, 2012).
    \7\ CAA section 181(a)(1), 40 CFR 51.1102 and 51.1103(a).
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    Designations of nonattainment for a given NAAQS trigger
requirements under the CAA to prepare and submit SIP revisions. The SIP
revisions that are the subject of today's proposed action address the
Severe-15 nonattainment area requirements that apply to the Coachella
Valley for the 2008 ozone NAAQS.
    Under California law, the California Air Resources Board (CARB) is
the state agency that is responsible for the adoption and submission to
the EPA of California SIPs and SIP revisions, and it has broad
authority to establish emissions standards and other requirements for
mobile sources. Local and regional air pollution control districts in
California are responsible for the regulation of stationary sources and
are generally responsible for the development of regional air quality
management plans (AQMPs or ``plans''). In the Coachella Valley, the
South Coast Air Quality Management District (SCAQMD or ``District'')
develops and adopts AQMPs to address CAA planning requirements
applicable to that region. Such plans are then submitted to CARB for
adoption and submittal to the EPA as revisions to the California SIP.

B. The Coachella Valley 2008 Ozone Nonattainment Area

    The Coachella Valley is located within Riverside County, and its
boundaries generally align with the Riverside County portion of the
Salton Sea Air Basin (SSAB). For a precise description of the
geographic boundaries of the Coachella Valley, see 40 CFR 81.305.
    Prior AQMPs and state control measures developed by the District
and CARB have produced significant emissions reductions over the years
and improved air quality in the Coachella Valley. For instance, the 8-
hour ozone design value for the Coachella Valley decreased from 0.110
ppm to 0.088 ppm from 1995 to 2015, despite increases in population and
vehicular activity.\8\
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    \8\ 2016 AQMP, Appendix II (``Current Air Quality''), Table A-8.
For the 8-hour ozone NAAQS, the design value at any given monitoring
site is the 3-year average of the annual fourth highest daily
maximum 8-hour average ambient air quality ozone concentration. The
maximum design value among the various ozone monitoring sites is the
design value for the area.
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    The Coachella Valley is downwind from the South Coast Air Basin
(``South

Coast'') and is subject to significant transport of ozone from that
area; both ozone nonattainment areas are regulated by the SCAQMD. The
Final 2016 Air Quality Management Plan describes ozone transport from
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the South Coast as follows:

    Atmospheric ozone in the Riverside county portion of the SSAB is
both directly transported from the Basin and formed photochemically
from precursors emitted upwind. The precursors are emitted in
greatest quantity in the coastal and central Los Angeles County
areas of the Basin. The Basin's prevailing sea breeze causes
polluted air to be transported inland. As the air is being
transported inland, ozone is formed, with peak concentrations
occurring in the inland valleys of the Basin, extending from eastern
San Fernando Valley through the San Gabriel Valley into the
Riverside-San Bernardino area and the adjacent mountains. As the air
is transported still further inland into the Coachella Valley
through the San Gorgonio Pass, ozone concentrations typically
decrease due to dilution, although ozone standards can still be
exceeded.\9\
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    \9\ ``Final 2016 Air Quality Management Plan,'' SCAQMD, March
2017, 7-9. See also 2007 AQMP, 7-23 (describing ozone transport
through the San Gorgonio Pass and citing early studies documenting
this transport).

    Because of the transport from the South Coast into the Coachella
Valley, continued progress in the South Coast towards meeting the 1997
and 2008 ozone NAAQS is critical for the Coachella Valley to attain the
2008 ozone NAAQS.

C. Clean Air Act and Regulatory Requirements for 2008 Ozone
Nonattainment Area SIPs

    States must implement the 2008 ozone NAAQS under title I, part D of
the CAA, including sections 171-179B of subpart 1 (``Nonattainment
Areas in General'') and sections 181-185 of subpart 2 (``Additional
Provisions for Ozone Nonattainment Areas''). To assist states in
developing effective plans to address ozone nonattainment problems, in
2015, the EPA issued a SIP Requirements Rule (SRR) for the 2008 ozone
NAAQS (``2008 Ozone SRR'') that addressed implementation of the 2008
standards, including attainment dates, requirements for emissions
inventories, attainment and reasonable further progress (RFP)
demonstrations, among other SIP elements, as well as the transition
from the 1997 ozone NAAQS to the 2008 ozone NAAQS and associated anti-
backsliding requirements.\10\ The regulatory requirements of the 2008
Ozone SRR are codified at 40 CFR part 51, subpart AA. We discuss the
CAA and regulatory planning requirements for the elements of 2008 ozone
plans relevant to this proposal in more detail below.
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    \10\ 80 FR 12264 (March 6, 2015). Anti-backsliding requirements
are the provisions applicable to revoked NAAQS (including the 1979
1-hour ozone NAAQS and the 1997 ozone NAAQS) as described in CAA
section 172(e).
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    The EPA's 2008 Ozone SRR was challenged, and on February 16, 2018,
the U.S. Court of Appeals for the D.C. Circuit (``D.C. Circuit'')
published its decision in South Coast Air Quality Management District
v. EPA (``South Coast II'') \11\ vacating portions of the 2008 Ozone
SRR. The only aspect of the South Coast II decision that affects this
proposed action is the vacatur of the alternative baseline year for
RFP. More specifically, the 2008 Ozone SRR required states to develop
the baseline emissions inventory for RFP using the emissions for the
most recent calendar year for which states submit a triennial inventory
to the EPA under subpart A (``Air Emissions Reporting Requirements'')
of 40 CFR part 51, which was 2011. However, the 2008 Ozone SRR allowed
states to use an alternative year, between 2008 and 2012, for the
baseline emissions inventory provided that the state demonstrated why
the alternative baseline year was appropriate. In the South Coast II
decision, the D.C. Circuit vacated the provisions of the 2008 Ozone SRR
that allowed states to use an alternative baseline year for
demonstrating RFP.
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    \11\ South Coast Air Quality Management District v. EPA, 882
F.3d 1138 (D.C. Cir. 2018). The term ``South Coast II'' is used in
reference to the 2018 court decision to distinguish it from a
decision published in 2006 also referred to as ``South Coast.'' The
earlier decision involved a challenge to the EPA's Phase 1
implementation rule for the 1997 ozone NAAQS. South Coast Air
Quality Management Dist. v. EPA, 472 F.3d 882 (D.C. Cir. 2006).
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II. Submissions From the State of California To Address 2008 Ozone
Requirements in the Coachella Valley

A. Summary of Submissions

    In this document, we are proposing action on portions of two SIP
revisions that are described in detail in the following paragraphs.
Collectively, we refer to the relevant portions of the two SIP
revisions as the ``2016 Coachella Valley Ozone SIP.''
1. SCAQMD's 2016 Air Quality Management Plan
    On April 27, 2017, CARB submitted the Final 2016 Air Quality
Management Plan (March 2017) (``2016 AQMP'') to the EPA as a revision
to the California SIP.\12\ The 2016 AQMP addresses the nonattainment
area requirements for the South Coast for the 2008 8-hour ozone NAAQS,
the 2006 fine particulate matter (PM2.5) NAAQS, and the 2012
PM2.5 NAAQS, and for the Coachella Valley for the 2008 8-
hour ozone NAAQS. It also updates the approved attainment
demonstrations for the 1979 1-hour ozone NAAQS and 1997 8-hour ozone
NAAQS for the South Coast and adds new measures to reduce the reliance
on section 182(e)(5) new technology measures to attain those standards.
On October 1, 2019, the EPA approved portions of the 2016 AQMP and
other submittals (collectively referred to as the ``2016 South Coast
Ozone SIP'') \13\ with respect to numerous requirements for the South
Coast relating to the 1979 1-hour, 1997 8-hour, and 2008 8-hour ozone
NAAQS.\14\ In today's notice, we are proposing action on the portions
of the 2016 AQMP that address the 2008 ozone NAAQS for the Coachella
Valley.
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    \12\ Letter dated April 27, 2017, from Richard Corey, Executive
Officer, CARB, to Alexis Strauss, Acting Regional Administrator, EPA
Region IX.
    \13\ The 2016 South Coast Ozone SIP includes five submittals:
The 2016 AQMP, the ``Revised Proposed 2016 State Strategy for the
State Implementation Plan,'' the ``2018 Updates to the California
State Implementation Plan,'' the ``Updated Federal 1979 1-Hour Ozone
Standard Attainment Demonstration,'' and a SCAQMD emissions
statement rule.
    \14\ 84 FR 52005. The EPA's proposed approval of the 2016 South
Coast Ozone SIP is at 84 FR 28132 (June 17, 2019). On February 12,
2019, we approved portions of the 2016 AQMP with respect to the 2006
PM2.5 NAAQS (except for the related contingency measure
element). See 84 FR 3305.
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    The SIP revision for the 2016 AQMP includes the various chapters
and appendices of the 2016 AQMP, described further below, plus the
District's resolution of adoption for the plan (District Resolution 17-
2) and CARB's resolution of adoption of the 2016 AQMP as a revision to
the California SIP (CARB Resolution 17-8) that includes commitments on
which the 2016 AQMP relies.\15\ With respect to ozone, the 2016 AQMP
addresses the CAA requirements for emissions inventories, air quality
modeling demonstrating attainment, reasonably available control
measures (RACM), RFP, transportation control strategies and measures,
and contingency measures for failure to make RFP, among other
requirements.
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    \15\ SCAQMD Board Resolution 17-2, March 3, 2017; CARB Board
Resolution 17-8, 2016 Air Quality Management Plan for Ozone and
PM2.5 in the South Coast and the Coachella Valley, March
23, 2017.
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    The 2016 AQMP is organized into eleven chapters. Most of the 2016
AQMP is directly relevant to the ozone and PM2.5 NAAQS in
the South Coast, and our review for this action addresses only those
portions of the 2016 AQMP that address the 2008 ozone NAAQS for

the Coachella Valley.\16\ The Coachella Valley is located in the SSAB,
which is separate from the upwind South Coast and faces different air
quality challenges. Chapter 7, ``Current and Future Air Quality--Desert
Nonattainment Areas SIP'' of the 2016 AQMP addresses CAA requirements
for the 2008 ozone NAAQS in the Coachella Valley.
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    \16\ The following chapters or portions thereof in the 2016 AQMP
were submitted for information only and are not subject to review as
part of the SIP revision: The portion of Chapter 6 that is titled
``California Clean Air Act Requirements'' and that discusses
compliance with state law requirements for clean air plans; Chapter
8, ``Looking Beyond Current Requirements,'' assesses the South
Coast's status with respect to the 2015 8-hour ozone standard of
0.070 ppm; 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, and the relationship between air quality
improvement and greenhouse gas mitigation goals. As noted
previously, we are not taking action in this rulemaking on the
portions of the 2016 AQMP that relate only to the South Coast.
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    Additional chapters in the 2016 AQMP also discuss the Coachella
Valley and provide relevant background. Chapter 1, ``Introduction,''
introduces the 2016 AQMP, including its purpose, historical air quality
progress in the South Coast and Coachella Valley, 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 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 and modeled attainment demonstration. Chapter 6,
``Federal and State Clean Air Act Requirements,'' discusses specific
federal and state requirements, 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 2016 AQMP. A glossary is
provided at the end of the document, presenting definitions of commonly
used terms found in the 2016 AQMP.
    The 2016 AQMP also includes the following technical appendices:
     Appendix I (``Health Effects'') presents a summary of
scientific findings on the health effects of ambient air pollutants.
     Appendix II (``Current Air Quality'') contains a detailed
summary of the air quality in 2015, 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 emission
inventories of air pollutants in future attainment years for both
annual average and summer planning inventories in the South Coast.
     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.
     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'' (2016 RTP/SCS) and transportation
control measures.
     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 2016
AQMP complies with specific CAA requirements.
    Attainment of the 2008 ozone NAAQS in the Coachella Valley is
heavily dependent on emission reductions occurring in the adjacent
South Coast. The emission reductions in the South Coast are described
in the 2016 South Coast Ozone SIP. As discussed in section III.D
(Attainment Demonstration) of the EPA's proposed approval of the 2016
South Coast Ozone SIP,\17\ the ozone attainment demonstrations for the
1997 and 2008 ozone NAAQS include commitments made by the District in
the 2016 AQMP and by CARB in the ``Revised Proposed 2016 State Strategy
for the State Implementation Plan'' (March 7, 2017) (``2016 State
Strategy''). The 2016 State Strategy does not include specific
commitments for the Coachella Valley. For details on the District and
CARB emissions reduction commitments in the 2016 South Coast Ozone SIP,
see the EPA's June 17, 2019 proposed approval action at 84 FR 28132.
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    \17\ 84 FR 28132 (June 17, 2019). On October 1, 2019, the EPA
finalized its approval of the 2016 South Coast Ozone SIP. See 84 FR
52005.
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2. CARB's 2018 Updates to the California State Implementation Plan
    On December 5, 2018, CARB submitted the 2018 Updates to the
California State Implementation Plan (``2018 SIP Update'') to the EPA
as a revision to the California SIP.\18\ CARB adopted the 2018 SIP
Update on October 25, 2018. CARB developed the 2018 SIP Update in
response to the court's decision in South Coast II vacating the 2008
Ozone SRR with respect to the use of an alternate baseline year for
demonstrating RFP, and to address contingency measure requirements in
the wake of the court decision in Bahr v. EPA.\19\ The 2018 SIP Update
includes updates for 8 different California ozone nonattainment areas.
We previously approved the San Joaquin Valley and South Coast portions
of the 2018 SIP Update.\20\ The 2018 SIP Update includes an RFP
demonstration using the required 2011 baseline year for the Coachella
Valley for the 2008 ozone NAAQS.\21\
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    \18\ Letter dated December 5, 2018, from Richard Corey,
Executive Officer, CARB, to Mike Stoker, Regional Administrator, EPA
Region IX.
    \19\ Bahr v. EPA, 836 F.3d 1218 (9th Cir. 2016). In this case,
the court rejected the EPA's longstanding interpretation of CAA
section 172(c)(9) as allowing for early implementation of
contingency measures. The court concluded that a contingency measure
must take effect at the time the area fails to make RFP or attain by
the applicable attainment date, not before.
    \20\ 84 FR 11198 (March 25, 2019) (final approval of the San
Joaquin Valley portion of the 2018 SIP Update) and 84 FR 52005
(October 1, 2019) (final approval of the South Coast portion of the
2018 SIP Update).
    \21\ Because we understand the State intended the RFP
demonstration for the Coachella Valley in the 2018 SIP Update to
replace the prior RFP demonstration in the 2016 AQMP submitted in
April 2017, we plan no further action on the RFP demonstration for
Coachella Valley in the 2016 AQMP.
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    The 2018 SIP Update also includes updated motor vehicle emissions
budgets and information to support the contingency measure element. To
supplement the contingency measures element of the 2016 Coachella
Valley Ozone SIP, the District has committed by letter to modify an
existing rule or adopt a new rule to create a contingency measure that
will be triggered if the area fails to meet an RFP milestone or attain
the 2008 ozone NAAQS.\22\ CARB transmitted the District's letter to the
EPA and committed to submit the revised District rule to the EPA as a
SIP revision within 12 months of the EPA's final action on the
contingency measure element of the 2016 Coachella Valley Ozone SIP.\23\
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    \22\ Letter dated August 2, 2019, from Wayne Nastri, SCAQMD
Executive Officer, to Richard Corey, Executive Officer, CARB.
    \23\ Letter dated September 9, 2019, from Michael Benjamin,
Chief, Air Quality and Science Division, CARB, to Amy Zimpfer,
Associate Director, Air Division, EPA Region IX.

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B. Clean Air Act Procedural Requirements for Adoption and Submission of
SIP Revisions

    CAA sections 110(a) and 110(l) require a state to provide
reasonable public notice and opportunity for public hearing prior to
the adoption and submission of a SIP or SIP revision. To meet this
requirement, every SIP submittal 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 have satisfied the applicable statutory
and regulatory requirements for reasonable public notice and hearing
prior to the adoption and submittal of the SIP revisions that compose
the 2016 Coachella Valley Ozone SIP. With respect to the 2016 AQMP, the
District held six regional workshops from July 14 through July 21,
2016, and four regional hearings on November 15 and 17, 2016, to
discuss the plan and solicit public input.\24\ On December 19 and 20,
2016, the District published notices in several local newspapers of a
public hearing to be held on February 3, 2017, for the adoption of the
2016 AQMP.\25\ On February 3, 2017, the District held the public
hearing, and on March 3, 2017, through Resolution 17-2, the District
adopted the 2016 AQMP and directed the Executive Officer to forward the
plan to CARB for inclusion in the California SIP.
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    \24\ See 2016 AQMP, Table 11-2.
    \25\ Memorandum dated January 24, 2017, from Denise Garzaro,
Clerk of the Boards, SCAQMD to Arlene Martinez, Administrative
Secretary, Planning, Rule Development and Area Sources, SCAQMD. The
memorandum includes copies of the proofs of publication of the
notice for the February 3, 2017 public hearing.
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    CARB also provided public notice and opportunity for public comment
on the 2016 AQMP. On March 6, 2017, CARB released for public review its
Staff Report for the 2016 AQMP and published a notice of public meeting
to be held on March 23, 2017, to consider adoption of the 2016
AQMP.\26\ On March 23, 2017, CARB held the hearing and adopted the 2016
AQMP as a revision to the California SIP, excluding those portions not
required to be submitted to the EPA, and directed the Executive Officer
to submit the 2016 AQMP to the EPA for approval into the California
SIP.\27\ On April 27, 2017, the Executive Officer of CARB submitted the
2016 AQMP to the EPA and included the transcript of the hearing held on
March 23, 2017.\28\ On October 23, 2017, the EPA determined that the
portions of this submittal applicable to the 2008 ozone NAAQS were
complete.\29\
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    \26\ 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 signed by Richard Corey,
Executive Officer, CARB, March 6, 2017.
    \27\ CARB Resolution 17-8, 10.
    \28\ Transcript of the March 23, 2017 Meeting of the State of
California Air Resources Board.
    \29\ Letter dated October 23, 2017, from Matthew J. Lakin,
Acting Director, Air Division, EPA Region IX to Richard Corey,
Executive Officer, CARB.
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    With respect to the 2018 SIP Update, CARB also provided public
notice and opportunity for public comment. On September 21, 2018, CARB
released for public review the 2018 SIP Update and published notice of
a public meeting to be held on October 23, 2018, to consider adoption
of the 2018 SIP Update.\30\ On October 23, 2018, through Resolution 18-
50, CARB adopted the 2018 SIP Update. On December 5, 2018, CARB
submitted the 2018 SIP Update to the EPA.
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    \30\ Notice of Public Meeting to Consider the 2018 Updates to
the California State Implementation Plan signed by Richard Corey,
Executive Officer, CARB, September 21, 2018.
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    Based on information provided in each of the SIP revisions
summarized above, the EPA has determined that all hearings were
properly noticed. Therefore, we find that the submittals of the 2016
AQMP and the 2018 SIP Update meet the procedural requirements for
public notice and hearing in CAA sections 110(a) and 110(l) and 40 CFR
51.102.

III. Review of the 2016 Coachella Valley Ozone SIP

A. Emissions Inventories

1. Statutory and Regulatory Requirements
    CAA sections 172(c)(3) and 182(a)(1) require states to submit for
each ozone nonattainment area a ``base year inventory'' that is a
comprehensive, accurate, current inventory of actual emissions from all
sources of the relevant pollutant or pollutants in the area. In
addition, the 2008 Ozone SRR requires that the inventory year be
selected consistent with the baseline year for the RFP demonstration,
which is the most recent calendar year for which a complete triennial
inventory is required to be submitted to the EPA under the Air
Emissions Reporting Requirements.\31\
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    \31\ 2008 Ozone SRR at 40 CFR 51.1115(a) and the Air Emissions
Reporting Requirements at 40 CFR part 51, subpart A.
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    The EPA has issued guidance on the development of base year and
future year emissions inventories for 8-hour ozone and other
pollutants.\32\ Emissions inventories for ozone must include emissions
of VOC and NOX and represent emissions for a typical ozone
season weekday.\33\ States should include documentation explaining how
the emissions data were calculated. In estimating mobile source
emissions, states should use the latest emissions models and planning
assumptions available at the time the SIP is developed.\34\
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    \32\ ``Emissions Inventory Guidance for Implementation of Ozone
and Particulate Matter National Ambient Air Quality Standards
(NAAQS) and Regional Haze Regulations,'' EPA-454/B-17-002, May 2017.
At the time the 2016 AQMP was developed, the following EPA emissions
inventory guidance applied: ``Emissions Inventory Guidance for
Implementation of Ozone and Particulate Matter National Ambient Air
Quality Standards (NAAQS) and Regional Haze Regulations'' EPA-454-R-
05-001, November 2005.
    \33\ 40 CFR 51.1115(a) and (c), and 40 CFR 51.1100(bb) and (cc).
    \34\ 80 FR 12264, 12290 (March 6, 2015).
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    Future baseline emissions inventories must reflect the most recent
population, employment, travel and congestion estimates for the area.
In this context, ``baseline'' emissions inventories refer to emissions
estimates for a given year and area that reflect rules and regulations
and other measures that are already adopted. Future baseline emissions
inventories are necessary to show the projected effectiveness of SIP
control measures. Both the base year and future year inventories are
necessary for photochemical modeling to demonstrate attainment.
2. Summary of State's Submission
    The 2016 AQMP includes a summary of the base year (2012) and future
year annual average baseline inventories for NOX and VOC for
the Coachella Valley. Documentation for the inventories is found in
Chapter 7 and Appendix III of the 2016 AQMP. Additionally, the District
provided the EPA with supplemental documentation (``2016 AQMP Inventory
Supplement'') for the 2012 and 2026 ozone season inventories relied on
in the 2016 AQMP.\35\ The 2018 SIP Update provides detailed
NOX and VOC inventories for 2011 (the base year used for
RFP) and 2012, and projected inventories for 2017, 2020, 2023, 2026,
and 2027. Because ozone levels in the Coachella Valley are typically
higher from May through October, the

inventories in the 2016 AQMP Inventory Supplement and the 2018 SIP
Update represent average summer day emissions. The inventories in the
2016 AQMP Inventory Supplement and 2018 SIP Update reflect District
rules adopted prior to December 2015 and CARB rules adopted by November
2015. For estimating on-road motor vehicle emissions, these inventories
use EMFAC2014, the EPA-approved version of California's mobile source
emissions model available at the time the 2016 AQMP and 2018 SIP Update
were developed.\36\
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    \35\ Email dated June 28, 2019, from Zorik Pirveysian, SCAQMD,
to John Ungvarsky, EPA, Subject: ``RE: Coachella Valley ozone
inventory clarification and update on possible contingency
measures.'' The 2016 AQMP Inventory Supplement consists of two
attachments to this email, which provide the detailed 2012 and 2026
ozone season inventories that were used for the summary in the 2016
AQMP. The inventories were generated on November 30, 2016.
    \36\ EMFAC is short for EMission FACtor. The EPA announced the
availability of the EMFAC2014 model for use in state implementation
plan 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 of the notice 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. See 84 FR 41717.
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    The VOC and NOX emissions estimates are grouped into two
general categories, stationary sources and mobile sources. Stationary
sources are further divided into ``point'' and ``area'' sources. Point
sources typically refer to permitted facilities and have one or more
identified and fixed pieces of equipment and emissions points. Area
sources consist of widespread and numerous smaller emissions sources,
such as small permitted facilities and households. The mobile sources
category is divided into two major subcategories, ``on-road'' and
``off-road'' mobile sources. On-road mobile sources include light-duty
automobiles, light-, medium-, and heavy-duty trucks, and motorcycles.
Off-road mobile sources include aircraft, locomotives, construction
equipment, mobile equipment, and recreational vehicles.
    Point source emissions for the 2012 base year emissions inventory
are calculated using reported data from facilities using the District's
annual emissions reporting program, which applies under District Rule
301 (``Permitting and Associated Fees'') to stationary sources in the
Coachella Valley that emit 4 tons per year (tpy) or more of VOC or
NOX. Area sources include smaller emissions 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 emissions
factors and activity information. Activity data are derived from
national survey data such as the Energy Information Administration or
from local sources such as the Southern California Gas Company, paint
suppliers, and District databases. Emissions factors used for the
estimates come from a number of sources including source tests,
compliance reports, and the EPA's compilation of emissions factor
document known as ``AP-42.''
    On-road emissions inventories in the 2016 AQMP Inventory Supplement
are calculated using CARB's EMFAC2014 model and the travel activity
data provided by SCAG in the 2016 RTP/SCS.\37\ 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 inventories are developed in conjunction with the
airports in the region.
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    \37\ See http://scagrtpscs.net/Pages/FINAL2016RTPSCS.aspx. SCAG
is the metropolitan planning organization for the Coachella Valley
and surrounding areas. The SCAG region encompasses six counties
(Imperial, Los Angeles, Orange, Riverside, San Bernardino and
Ventura) and 191 cities in an area covering more than 38,000 square
miles.
    \38\ 2016 AQMP, Appendix III, page III-1-24.
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    Table 1 provides a summary of the District's 2012 base year and
2026 attainment year baseline emissions estimates in tons per average
summer day for NOX and VOC. These inventories provide the
basis for the control measure analysis and the attainment
demonstrations in the 2016 AQMP. Based on the inventory for 2012,
stationary and area sources currently account for 39 percent of the VOC
emissions and less than 5 percent of the NOX emissions in
the Coachella Valley while mobile sources account for 61 percent of the
VOC emissions and over 95 percent of the NOX emissions. For
a more detailed discussion of the methodologies used to develop the
inventories, see Appendix III of the 2016 AQMP.

             Table 1--Coachella Valley Base Year and Attainment Year Baseline Emissions Inventories
                                 [Summer planning inventory, tons per day (tpd)]
----------------------------------------------------------------------------------------------------------------
                                                               2012                            2026
                    Category                     ---------------------------------------------------------------
                                                        NOX             VOC             NOX             VOC
----------------------------------------------------------------------------------------------------------------
Stationary and Area Sources.....................             1.2             6.4             1.4             8.8
On-Road Mobile Sources..........................            18.9             6.4             4.1             2.9
Off-Road Mobile Sources.........................             6.5             3.7             3.6             3.3
                                                 ---------------------------------------------------------------
    Total.......................................            26.6            16.5             9.1            15.1
----------------------------------------------------------------------------------------------------------------
Sources: 2016 AQMP Inventory Supplement and 2018 SIP Update, Table VII-1. The sum of the emissions values may
  not equal the total due to rounding of the numbers.

    Future emissions forecasts are primarily based on demographic and
economic growth projections provided by SCAG, and control factors
developed by the District in reference to the 2012 base year. Growth
factors used to project these baseline inventories are derived mainly
from data obtained from SCAG.\39\
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    \39\ 2016 AQMP, 7-25, and Appendix III, page III-2-6.
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3. The EPA's Review of the State's Submission
    We have reviewed the 2012 base year emissions inventory in the 2016
AQMP Inventory Supplement and the inventory methodologies used by the
District and CARB for consistency with CAA requirements and EPA
guidance. First, we find that the 2012 inventory includes estimates for
VOC and NOX for a typical ozone season weekday, and that
CARB has provided adequate documentation explaining how the emissions
are calculated. Second, we find that the 2012 base year emissions
inventory in the 2016 AQMP Inventory Supplement reflects appropriate

emissions models and methodologies, and, therefore, represents a
comprehensive, accurate, and current inventory of actual emissions
during that year in the Coachella Valley nonattainment area. Third, we
find that selection of year 2012 for the base year emissions inventory
is appropriate because it is consistent with the 2011 RFP baseline year
(from the 2018 SIP Update) because both inventories are derived from a
common set of models and methods. Therefore, the EPA is proposing to
approve the 2012 emissions inventory in the 2016 AQMP Inventory
Supplement as meeting the requirements for a base year inventory set
forth in CAA section 182(a)(1) and 40 CFR 51.1115.\40\
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    \40\ The 2012 base year inventory from the 2016 AQMP Inventory
Supplement revises and updates the base year emission inventory
included in the ``8-Hour Ozone State Implementation Plan Emission
Inventory Submittal'' submitted by CARB on July 17, 2014. Because we
understand the State intended the 2016 AQMP and the 2016 AQMP
Inventory Supplement to replace the July 2014 submittal (at least
with respect to Coachella Valley), we plan no further action on the
inventory for Coachella Valley submitted by CARB in July 2014.
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    With respect to the 2026 attainment year baseline projections, we
have reviewed the growth and control factors and find them acceptable
and conclude that the future baseline emissions projections in the 2016
AQMP Inventory Supplement reflect appropriate calculation methods and
the latest planning assumptions. Also, as a general matter, the EPA
will approve a SIP revision that takes emissions reduction credit for a
control measure only where the EPA has approved the measure as part of
the SIP. Thus, to take credit for the emissions reductions from newly-
adopted or amended District rules for stationary sources, the related
rules must be approved by the EPA into the SIP. Table 2 in the
technical support document (TSD) accompanying this rulemaking shows
District rules with post-2012 compliance dates that were incorporated
in the future year inventories, along with information on EPA approval
of these rules, and shows that emissions reductions assumed by the 2016
AQMP for future years for stationary sources are supported by rules
approved as part of the SIP. With respect to mobile sources, the EPA
has taken action in recent years to approve CARB mobile source
regulations into the California SIP.\41\ We therefore find that the
future year baseline projections in the 2016 AQMP Inventory Supplement
are properly supported by SIP-approved stationary and mobile source
measures.\42\
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    \41\ See 81 FR 39424 (June 16, 2016), 82 FR 14446 (March 21,
2017), and 83 FR 23232 (May 18, 2018).
    \42\ The baseline emissions projections in the 2016 South Coast
Ozone SIP assume implementation of CARB's Zero Emissions Vehicle
(ZEV) sales mandate and greenhouse gas (GHG) standards. On September
27, 2019, the U.S. Department of Transportation and the EPA issued a
notice of final rulemaking for the Safer Affordable Fuel-Efficient
(SAFE) Vehicles Rule Part One: One National Program that, among
other things, withdrew the EPA's 2013 waiver of preemption of CARB's
ZEV sales mandate and GHG standards. 84 FR 51310. See also proposed
SAFE rule at 83 FR 42986 (August 24, 2018). However, the agencies'
final rule withdrawing the 2013 waiver did not include final action
on the federal fuel economy and GHG vehicle emissions standards from
the SAFE proposal. If the fuel economy and GHG standards are
finalized prior to our final rulemaking on the 2016 Coachella Valley
Ozone SIP, we will evaluate and address, as appropriate, the impact
of the SAFE action on our proposed action.
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B. Emissions Statement

1. Statutory and Regulatory Requirements
    Section 182(a)(3)(B)(i) of the Act requires states to submit a SIP
revision requiring owners or operators of stationary sources of VOC or
NOX to provide the state with statements of actual emissions
from such sources. Statements must be submitted at least every year and
must contain a certification that the information contained in the
statement is accurate to the best knowledge of the individual
certifying the statement. Section 182(a)(3)(B)(ii) of the Act allows
states to waive the emissions statement requirement for any class or
category of stationary sources that emit less than 25 tpy of VOC or
NOX, if the state provides an inventory of emissions from
such class or category of sources as part of the base year or periodic
inventories required under CAA sections 182(a)(1) and 182(a)(3)(A),
based on the use of emissions factors established by the EPA or other
methods acceptable to the EPA.
    The preamble of the 2008 Ozone SRR states that if an area has a
previously approved emissions statement rule for the 1997 ozone NAAQS
or the 1-hour ozone NAAQS that covers all portions of the nonattainment
area for the 2008 ozone NAAQS, such rule should be sufficient for
purposes of the emissions statement requirement for the 2008 ozone
NAAQS. The state should review the existing rule to ensure it is
adequate and, if so, may rely on it to meet the emissions statement
requirement for the 2008 ozone NAAQS.\43\ Where an existing emissions
statement requirement is still adequate to meet the requirements of
this rule, states can provide the rationale for that determination to
the EPA in a written statement in the SIP to meet this requirement.
States should identify the various requirements and how each is met by
the existing emissions statement program. Where an emissions statement
requirement is modified for any reason, states must provide the
revision to the emissions statement as part of its SIP.
---------------------------------------------------------------------------

    \43\ See 80 FR 12264, at 12291 (March 6, 2015).
---------------------------------------------------------------------------

2. Summary of the State's Submission
    The 2016 AQMP addresses compliance with the emissions statement
requirement in CAA section 182(a)(3)(B) for the 2008 ozone NAAQS by
reference to District Rule 301 that, among other things, requires
emissions reporting from all stationary sources of NOX and
VOC greater than or equal to 4 tpy. District Rule 301 applies
throughout both the South Coast and the Coachella Valley. On July 12,
2019, the District adopted revisions to District Rule 301 to meet the
requirements in CAA section 182(a)(3)(B), and on July 19, 2019, the
District submitted to CARB a request for Rule 301 to be included into
the California SIP and forwarded to the EPA. On August 5, 2019, CARB
adopted and submitted paragraphs (e)(1)(A) and (B), (e)(2), (e)(5) and
(e)(8) of District Rule 301 to the EPA as a revision to the California
SIP. The submittal includes CARB Executive Order S-19-011 adopting the
specified sections of District Rule 301 as a revision to the SIP, a
copy of District Rule 301 itself, and documentation of public notice
and opportunity to comment on the draft rule.
3. The EPA's Review of the State's Submission
    On October 1, 2019, as part of our approval of the 2016 South Coast
Ozone SIP, the EPA approved portions of District Rule 301 (paragraphs
(e)(1)(A) and (B), (e)(2), (e)(5) and (e)(8)) as meeting the emissions
statement requirement under CAA section 182(a)(3)(B) for the South
Coast for the 2008 ozone NAAQS.\44\ Rule 301 is effective throughout
both the South Coast and the Coachella Valley. Therefore, the approved
portions of District Rule 301 also satisfy the CAA 182(a)(3)(B)
requirements for the 2008 ozone NAAQS in the Coachella Valley.
---------------------------------------------------------------------------

    \44\ 84 FR 52005, 52015.
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C. Reasonably Available Control Measures Demonstration and Control
Strategy

1. Statutory and Regulatory Requirements
    CAA section 172(c)(1) requires that each attainment plan provide
for the implementation of all RACM as

expeditiously as practicable (including such reductions in emissions
from existing sources in the area as may be obtained through
implementation of reasonably available control technology (RACT)), and
also provide for attainment of the NAAQS. The 2008 Ozone SRR requires
that, for each nonattainment area required to submit an attainment
demonstration, the state concurrently submit a SIP revision
demonstrating that it has adopted all RACM necessary to demonstrate
attainment as expeditiously as practicable and to meet any RFP
requirements.\45\
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    \45\ 40 CFR 51.1112(c).
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    The EPA has previously provided guidance interpreting the RACM
requirement in the General Preamble for the Implementation of the Clean
Air Act Amendments of 1990 (``General Preamble'') and in a memorandum
entitled ``Guidance on the Reasonably Available Control Measure
Requirement and Attainment Demonstration Submissions for Ozone
Nonattainment Areas.'' \46\ In short, to address the requirement to
adopt all RACM, states should consider all potentially reasonable
control measures for source categories in the nonattainment area to
determine whether they are reasonably available for implementation in
that area and whether they would, if implemented individually or
collectively, advance the area's attainment date by one year or
more.\47\ Any measures that are necessary to meet these requirements
that are not already either federally promulgated, or part of the
state's SIP, must be submitted in enforceable form as part of the
state's attainment plan for the area.\48\
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    \46\ See General Preamble, 57 FR 13498, 13560 (April 16, 1992)
and memorandum dated November 30, 1999, from John Seitz, Director,
OAQPS, to Regional Air Directors, titled ``Guidance on the
Reasonably Available Control Measure Requirement and Attainment
Demonstration Submissions for Ozone Nonattainment Areas.''
    \47\ Id. See also 44 FR 20372 (April 4, 1979), and memorandum
dated December 14, 2000, from John S. Seitz, Director, OAQPS, to
Regional Air Directors, titled ``Additional Submission on RACM From
States with Severe One-Hour Ozone Nonattainment Area SIPs.''
    \48\ For ozone nonattainment areas classified as Moderate or
above, CAA section 182(b)(2) also requires implementation of RACT
for all major sources of VOC and for each VOC source category for
which the EPA has issued a control techniques guideline. CAA section
182(f) requires that RACT under section 182(b)(2) also apply to
major stationary sources of NOX. In Severe areas, a major
source is a stationary source that emits or has the potential to
emit at least 25 tpy of VOC or NOX (see CAA section
182(e) and (f)). Under the 2008 Ozone SRR, states were required to
submit SIP revisions meeting the RACT requirements of CAA sections
182(b)(2) and 182(f) no later than 24 months after the effective
date of designation for the 2008 Ozone NAAQS and to implement the
required RACT measures as expeditiously as practicable but no later
than January 1 of the 5th year after the effective date of
designation (see 40 CFR 51.1112(a)). California submitted the CAA
section 182 RACT SIP for the South Coast and the Coachella Valley on
July 18, 2014, and the EPA fully approved this submission at 82 FR
43850 (September 20, 2017).
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2. Summary of the State's Submission
    For the 2016 Coachella Valley Ozone SIP, the District, CARB, and
SCAG each undertook a process to identify and evaluate potential RACM
that could contribute to expeditious attainment of the 2008 ozone NAAQS
in the Coachella Valley. The RACM demonstration for the Coachella
Valley is the same demonstration undertaken for the 2016 South Coast
Ozone SIP that the EPA approved on November 1, 2019.\49\
---------------------------------------------------------------------------

    \49\ 84 FR 52005.
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a. District's RACM Analysis
    The District's RACM demonstration for the 2008 ozone NAAQS focuses
on stationary and area source controls, and it is described in Appendix
VI-A (``Reasonably Available Control Measures (RACM)/Best Available
Control Measures (BACM) Demonstration'') of the 2016 AQMP. Appendix VI-
A identifies potential control measures and analyzes these measures for
emission reduction opportunities, as well as economic and technological
feasibility. The District's comprehensive demonstration considers
potential control measures for stationary and area sources located
throughout the areas under its jurisdiction, including both the South
Coast (where most of the sources are located) and the Coachella Valley.
Therefore, the demonstration includes not only all of the source
categories present in the Coachella Valley, but also the source
categories found only in the South Coast.
    As a first step in the RACM analysis, the District prepared a
detailed inventory of emissions sources that emit VOC and
NOX to identify source categories from which emissions
reductions would effectively contribute to attainment. Details on the
methodology and development of the emissions inventory are discussed in
Chapter 7 and Appendix III of the 2016 AQMP. A total of 76 source
categories are included in the base year emissions inventory: 46 for
stationary and area sources and 30 for mobile sources.\50\
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    \50\ 2016 AQMP, Appendix VI-A, Table VI-A-3. The majority of the
stationary emissions sources included in this inventory are located
in the South Coast. The 2016 AQMP identifies only two stationary
sources (i.e., Desert View Power and Imperial Irrigation District)
emitting 10 tpy or more of either VOC or NOX in 2012
located within the Coachella Valley. See 2016 AQMP, Appendix III,
Attachment C. CARB's Facility Search Engine database shows three
sources (i.e., Desert View Power, Palm Springs International
Airport, and Sentinel Energy Center LLC) emitting 10 tpy or more of
either VOC or NOX emissions in 2017 located in the
Coachella Valley. See the docket for today's action or go to CARB's
database at https://www.arb.ca.gov/app/emsinv/facinfo/facinfo.php
and set Air Basin search filter to ``Salton Sea.''
---------------------------------------------------------------------------

    For the RACM analysis, the District then compared these source
categories to its rules for stationary and area sources. This analysis
builds upon a foundation of District rules developed for earlier ozone
plans and approved as part of the SIP. We provide a list of the
District's NOX and VOC rules approved into the California
SIP in Table 1 of our TSD for this proposed action. The 86 SIP-approved
District VOC or NOX rules listed in Table 1 of our TSD
establish emissions limits or other types of emissions controls for a
wide range of sources, including use of solvents, refineries, gasoline
storage, architectural coatings, spray booths, various types of
commercial coatings, boilers, steam generators and process heaters, oil
and gas production well, marine tank vessel operations, and many more.
These rules have already provided significant reductions toward
attainment of the 2008 ozone NAAQS by 2026.
    To demonstrate that the SCAQMD considered all candidate measures
that are available and technologically and economically feasible, the
District conducted a six-step analysis, as described below.
Step 1. 2015 Air Quality Technology Symposium (``2015 Symposium'')
    The 2015 Symposium was held on June 10 and 11, 2015, with
participation of technical experts and the public to solicit new and
innovative concepts to assist in attaining the 1997 and 2008 ozone
NAAQS by the applicable attainment dates. The SCAQMD also conducted
extensive outreach to engage a wide range of stakeholders in the
process.
Step 2. Reasonably Available Control Technology/Best Available Control
Technology Analysis
    The District's Reasonably Available Control Technology/Best
Available Control Technology (RACT/BACT) analysis \51\ found four
SCAQMD VOC or NOX rules (i.e., District Rules 462 (``Organic
Liquid Loading''), 1115 (``Motor Vehicle Assembly Line Coating
Operations''), 1118 (``Control of Emissions from Refinery Flares'') and
1138 (``Control of Emissions from

Restaurant Operations'')) that are less stringent than EPA control
techniques guidelines or analogous rules in other air districts. The
SCAQMD evaluated the rules as candidate potential measures. See section
IV of the TSD for this action for the EPA's evaluation of the four
rules.
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    \51\ BACM, including BACT, is a requirement for certain
PM2.5 nonattainment areas. BACM is not a requirement for
ozone nonattainment areas, but because the District addresses both
PM2.5 and ozone in its 2016 AQMP, the District prepared
an analysis that addresses both RACT and BACT.
---------------------------------------------------------------------------

Step 3. EPA TSDs
    The District researched TSDs from recent EPA rulemakings on SCAQMD
rules for EPA recommendations on potential control measures. The TSD
for the EPA's action on District Rule 1125 (``Metal Container, Closure,
and Coil Coating Operations,'' amended March 7, 2008) was the only
applicable and recent TSD that met the criteria for review.
Step 4. Control Measures in Other Areas
    The District reviewed control measures in other areas (i.e.,
Ventura County, San Francisco Bay Area, San Joaquin Valley, Sacramento
Metropolitan, Dallas-Fort Worth and Houston-Galveston-Brazoria, New
York, and New Jersey) to evaluate whether control technologies
available and cost-effective within other areas would be available and
cost-effective for use in the South Coast and the Coachella Valley.
Step 5. Control Measures beyond RACM in 2012 AQMP
    The District updated the RACM analysis for four control measures
that were determined to be beyond RACM in the analysis for the prior
2012 AQMP, including reconsideration of emissions reductions of VOC
from greenwaste composting.
Step 6. EPA Menu of Control Measures
    The Menu of Control Measures (MCM) \52\ compiled by the EPA's
Office of Air Quality Planning and Standards was created to provide
information useful in the development of emissions reduction strategies
and to identify and evaluate potential control measures. District staff
reviewed the MCM for point and nonpoint sources of NOX and
VOC.
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    \52\ EPA, MCM, http://www3.epa.gov/ttn/naaqs/pdfs/MenuOfControlMeasures.pdf.
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    The District provides a comprehensive evaluation of its RACM
control strategy in Appendix VI-A of the 2016 AQMP. The evaluation
includes the following: Source descriptions; base year and projected
baseline year emissions for the source category affected by the rule;
discussion of the current requirements of the rule; and discussion of
potential additional control measures, including, in many cases, a
discussion of the technological and economic feasibility of the
additional control measures. This includes comparison of each District
rule to analogous control measures adopted by other agencies.
    Based on its RACM analysis for stationary and area sources under
its jurisdiction, the District identified the following three
additional RACM with quantifiable VOC and NOX emission
reductions: 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; and
BCM-10--Emission Reductions from Greenwaste Composting. These three
RACM are included in the District's stationary source measures in Table
4-2 of the 2016 AQMP that the District Board adopted through Resolution
17-2. For the few remaining measures that the District rejected from
its RACM analysis, the District determined that these measures would
not collectively advance the attainment date or contribute to RFP due
to the uncertain or non-quantifiable emissions reductions they would
potentially generate.\53\
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    \53\ 2016 AQMP, Appendix VI-A, page VI-A-40, and Attachments VI-
A-1c, VI-A-1d, and VI-A-2.
---------------------------------------------------------------------------

    Based on its evaluation of all available measures, the District
concluded that its existing rules are generally as stringent as, or
more stringent than, the analogous rules in other districts. Further,
the District concluded that, based on its comprehensive review and
evaluation of potential candidate measures and the adoption of
commitments to implement the three measures determined to be
technologically and economically feasible, the District meets the RACM
requirement for the 2008 ozone NAAQS for all sources under the
District's jurisdiction.
    Lastly, the District concluded that its controls will achieve
attainment for the ozone standards as expeditiously as possible, and
that the available control measures not included as plan commitments
would not collectively advance attainment.\54\
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    \54\ 2016 AQMP, Appendix VI, page VI-A-40.
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b. Local Jurisdictions' RACM Analysis and Transportation Control
Measures
    Appendix IV-C of the 2016 AQMP, contains the transportation control
measure (TCM) RACM component for the 2016 South Coast Ozone SIP. The
TCMs in Appendix IV-C are applicable in the upwind South Coast Air
Basin. Because of the significant influence of pollutant transport from
the South Coast Air Basin on ozone conditions in the Coachella Valley,
neither the District nor CARB rely on implementation of any TCMs in the
Coachella Valley to demonstrate implementation of RACM in the 2016
Coachella Valley Ozone SIP. SCAG conducted the TCM RACM analysis on
behalf of the local jurisdictions in its region, based on its 2016 RTP/
SCS and 2015 Federal Transportation Improvement Program (FTIP), as
amended.\55\ The 2016 RTP/SCS and FTIP were developed in consultation
with federal, state and local transportation and air quality planning
agencies and other stakeholders. The four county transportation
commissions (CTCs),\56\ including the Riverside CTC overseeing the
Coachella Valley, were involved in the development of the regional
transportation measures in Appendix IV-C.\57\
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    \55\ The 2016 RTP/SCS was adopted by SCAG's Regional Council on
April 7, 2016. The 2015 FTIP was adopted by SCAG's Executive/
Administration Committee on September 11, 2014, and approved by the
Federal Highway Administration on December 14, 2014.
    \56\ Los Angeles County Metropolitan Transportation Authority,
Riverside County Transportation Commission, Orange County
Transportation Authority, and the San Bernardino County
Transportation Authority (formerly known as the San Bernardino
Associated Governments).
    \57\ 2016 AQMP, Appendix IV-C, page IV-C-1.
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    As described in Appendix IV-C of the 2016 AQMP, for the TCM RACM
analysis, SCAG compared the list of measures implemented within the
South Coast with those implemented in other ozone and PM2.5
nonattainment areas.\58\ SCAG then organized measures, including
candidate measures and those measures currently implemented in the
region, according to the sixteen categories specified in section
108(f)(1)(A) of the CAA. SCAG found a small number of candidate
measures that were not currently implemented in the region and not
included in the prior 2012 AQMP TCM RACM analysis. Attachment A
(``Committed Transportation Control Measures (TCMs)'') to Appendix IV-C
of the 2016 AQMP lists the TCM projects that are specifically
identified and committed to in the 2016 AQMP. The complete listing of
all candidate measures evaluated for the RACM determination is included
in Attachment B (``2016 South Coast AQMP Reasonably Available Control
Measures (RACM) Analysis--TCMs'') to Appendix IV-C of the 2016 AQMP.
Based on its comprehensive review of TCM projects in other
nonattainment

areas or otherwise identified, SCAG determined that the TCMs being
implemented in the South Coast are inclusive of all RACM.\59\
---------------------------------------------------------------------------

    \58\ The specific nonattainment area SIPs that were reviewed for
candidate TCMs for ozone are listed in Table 4 of Appendix IV-C of
the 2016 AQMP.
    \59\ Appendix IV-C, page IV-C-30.
---------------------------------------------------------------------------

c. CARB's RACM Analysis
    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 AQMP.
    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 AQMP. The BACM/RACM assessment and 2016 State Strategy
collectively contain CARB's evaluation of mobile source and other
statewide control measures that reduce emissions of NOX and
VOC in California, including the Coachella Valley. The 2016 State
Strategy also includes a commitment to take action on new measures and
to achieve aggregate emissions reductions in the South Coast.\60\
Because the Coachella Valley's attainment of the 2008 ozone NAAQS is
dependent on progress made in the upwind South Coast, this commitment
will contribute to attainment in the Coachella Valley. On October 1,
2019, the EPA approved the 2016 South Coast Ozone SIP, including CARB's
commitment.\61\ For additional details on CARB's commitment, see
section III.D.2.b.ii of our notice for the proposed action.\62\
---------------------------------------------------------------------------

    \60\ 2016 State Strategy, Chapter 3 (``Proposed SIP
Commitment''),
    \61\ 84 FR 52005, 52015.
    \62\ 84 FR 28132, 28147.
---------------------------------------------------------------------------

    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, motor vehicle fuels, and consumer
products. CARB developed its 2016 State Strategy through a multi-step
measure development process, including extensive public consultation,
to develop and evaluate potential strategies for mobile source
categories under CARB's regulatory authority that could contribute to
expeditious attainment of the standard.\63\ Through the process of
developing the 2016 State Strategy, CARB identified certain defined
measures as available to achieve additional VOC and NOX
emissions reductions from sources under CARB jurisdiction, including
tighter requirements for new light- and medium-duty vehicles (referred
to as the ``Advanced Clean Cars 2'' measure), a low-NOX
engine standard for vehicles with new heavy-duty engines, tighter
emissions standards for small off-road engines, and more stringent
requirements for consumer products, among others.\64\ In adopting the
2016 State Strategy, CARB commits to bringing the defined measures to
the CARB Board for action according to the specific schedule included
as part of the strategy.\65\
---------------------------------------------------------------------------

    \63\ Appendix VI-A, Attachment VI-A-3, page VI-A-102.
    \64\ 2016 State Strategy, Chapter 4 (``State SIP Measures'').
    \65\ CARB Resolution 17-7 (dated March 23, 2017), 7.
---------------------------------------------------------------------------

    Given the need for substantial emissions reductions from mobile and
area sources to meet the NAAQS in California nonattainment areas, CARB
established stringent control measures for on-road and off-road mobile
sources and the fuels that power them. California has unique authority
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.
    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 been submitted and approved as revisions to the
California SIP.\66\
---------------------------------------------------------------------------

    \66\ 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 inspection and maintenance program at 75 FR 38023 (July 1,
2010).
---------------------------------------------------------------------------

    In the BACM/RACM assessment, CARB concludes that, in light of the
extensive public process culminating in the 2016 State Strategy, with
the current mobile source program and proposed measures included in the
2016 State Strategy, there are no additional RACM that would advance
attainment of the 2008 ozone NAAQS in the South Coast. As a result,
CARB concludes that California's mobile source programs fully meet the
RACM requirement.\67\
---------------------------------------------------------------------------

    \67\ 2016 AQMP, Appendix VI, page VI-A-106.
---------------------------------------------------------------------------

    Appendix IV-B of the 2016 AQMP describes CARB's current consumer
products program and commitments in the 2016 State Strategy to achieve
additional VOC reductions from consumer products.\68\ As described in
this section, CARB's current consumer products program limits VOC
emissions from 129 consumer product categories, including product
categories such as antiperspirants and deodorants and aerosol
coatings.\69\ The EPA has approved many of these measures into the
California SIP as VOC emissions controls for a wide array of consumer
products.\70\
---------------------------------------------------------------------------

    \68\ 2016 AQMP, Appendix IV-B, page IV-B-93. CARB's consumer
product measures are found in the California Code of Regulations,
Title 17 (``Public Health''), Division 3 (``Air Resources''),
Chapter 1 (``Air Resources Board''), Subchapter 8.5 (``Consumer
Products'').
    \69\ 2016 AQMP, Appendix IV-B, page IV-B-93.
    \70\ The compilation of such measures that have been approved
into the California SIP, including Federal Register citations, is
available at: https://www.epa.gov/sips-ca/epa-approved-regulations-california-sip. EPA's most recent approval of amendments to
California's consumer products regulations was in 2014. 79 FR 62346
(October 17, 2014).
---------------------------------------------------------------------------

3. The EPA's Review of the State's Submission
    As described above, the District already implements many rules to
reduce VOC and NOX emissions from stationary and area
sources in the Coachella Valley. For the 2016 AQMP, the District
evaluated a range of potentially available measures and committed to
adopt certain additional measures (i.e., CMB-02, CMB-03, and BCM-10)
found to be reasonably available for implementation in the South Coast
and Coachella Valley nonattainment areas. We find that the process
followed by the District in the 2016 AQMP to identify additional RACM
is generally consistent with the EPA's recommendations in the General
Preamble, that the District's evaluation of potential measures is
appropriate, and that the District has provided reasoned justifications
for rejection of measures deemed not reasonably available.
    With respect to mobile sources, CARB's current program addresses
the full range of mobile sources in the South Coast and Coachella
Valley through regulatory programs for both new and in-use vehicles.
Moreover, we find that the process conducted by CARB to prepare the
2016 State Strategy was reasonably designed to identify additional
available measures within CARB's jurisdiction, and that CARB has

adopted those measures that are reasonably available (e.g., the low-
NOX heavy-duty engine standard, among others). With respect
to TCMs, we find that SCAG's process for identifying additional TCM
RACM and conclusion that the TCMs being implemented in the South Coast
(i.e., the TCMs listed in Attachment A to Appendix IV-C of the 2016
AQMP) are inclusive of all TCM RACM to be reasonably justified and
supported. For the 2016 Coachella Valley Ozone SIP, given the
significant influence of pollutant transport from the South Coast Air
Basin and the minimal and diminishing emissions benefits generally
associated with TCMs, no TCM or combination of TCMs implemented in the
Coachella Valley would advance the attainment date in the Coachella
Valley. Therefore, no TCMs are reasonably available for implementation
in the Coachella Valley for the purposes of meeting the RACM
requirement.
    Additionally, we find that CARB's consumer products program
comprehensively addresses emissions from consumer products in the South
Coast and Coachella Valley. CARB measures are more stringent than the
EPA's consumer products regulation promulgated in 1998,\71\ and
generally exceed the controls in place throughout other areas of the
country. The additional commitments included in the 2016 State Strategy
will further strengthen this program by achieving additional VOC
reductions.
---------------------------------------------------------------------------

    \71\ 63 FR 48819 (September 11, 1998).
---------------------------------------------------------------------------

    Based on our review of these RACM analyses, the District's and
CARB's adopted rules, and the District's commitment to adopt three
additional reasonably available measures (i.e., CMB-02, CMB-03, and
BCM-10), we propose to find that there are currently no additional RACM
(including RACT) that would advance attainment of the 2008 ozone NAAQS
in the Coachella Valley, and that the 2016 Coachella Valley Ozone SIP
provides for the implementation of all RACM as required by CAA section
172(c)(1) and 40 CFR 51.1112(c). For additional background on the EPA's
evaluation of the District's RACM analysis, see our June 17, 2019
notice of proposed rulemaking on the 2016 South Coast Ozone SIP.\72\
---------------------------------------------------------------------------

    \72\ 84 FR 28132, 28140. See also the EPA's November 1, 2019
approval of the 2016 South Coast Ozone SIP at 84 FR 52005.
---------------------------------------------------------------------------

D. Attainment Demonstration

1. Statutory and Regulatory Requirements
    An attainment demonstration consists of: (1) Technical analyses,
such as base year and future year modeling, to locate and identify
sources of emissions that are contributing to violations of the ozone
NAAQS within the nonattainment area (i.e., analyses related to the
emissions inventory for the nonattainment area and the emissions
reductions necessary to attain the standards); (2) a list of adopted
measures (including RACT controls) with schedules for implementation
and other means and techniques necessary and appropriate for
demonstrating RFP and attainment as expeditiously as practicable but no
later than the outside attainment date for the area's classification;
(3) a RACM analysis; and (4) contingency measures required under
sections 172(c)(9) and 182(c)(9) of the CAA that can be implemented
without further action by the state or the EPA to cover emissions
shortfalls in RFP and failures to attain.\73\ This subsection of
today's proposed rule addresses the first two components of the
attainment demonstration--the technical analyses and a list of adopted
measures. Section III.C (Reasonably Available Control Measures
Demonstration and Control Strategy) of this document addresses the RACM
component, and section III.G (Contingency Measures) addresses the
contingency measures component of the attainment demonstration in the
2016 Coachella Valley Ozone SIP.
---------------------------------------------------------------------------

    \73\ 78 FR 34178, 34184 (June 6, 2013) (proposed rule for
implementing the 2008 ozone NAAQS).
---------------------------------------------------------------------------

    With respect to the technical analyses, section 182(c)(2)(A) of the
CAA requires that a plan for an ozone nonattainment area classified
Serious or above include a ``demonstration that the plan . . . will
provide for attainment of the ozone [NAAQS] by the applicable
attainment date. This attainment demonstration must be based on
photochemical grid modeling or any other analytical method determined .
. . to be at least as effective.'' The attainment demonstration
predicts future ambient concentrations for comparison to the NAAQS,
making use of available information on measured concentrations,
meteorology, and current and projected emissions inventories of ozone
precursors, including the effect of control measures in the plan.
    Areas classified Severe for the 2008 ozone NAAQS must demonstrate
attainment as expeditiously as practicable, but no later than 15 years
after the effective date of designation to nonattainment. The Coachella
Valley was designated nonattainment for the 2008 ozone NAAQS effective
July 20, 2012,\74\ and accordingly the area must demonstrate attainment
of the standards by July 20, 2027.\75\ An attainment demonstration must
show attainment of the standards by the calendar year prior to the
attainment date, so in practice, Severe nonattainment areas must
demonstrate attainment in 2026.
---------------------------------------------------------------------------

    \74\ 77 FR 30087 (May 21, 2012).
    \75\ 80 FR 12264.
---------------------------------------------------------------------------

    The EPA's recommended procedures for modeling ozone as part of an
attainment demonstration are contained in ``Modeling Guidance for
Demonstrating Air Quality Goals for Ozone, PM2.5, and
Regional Haze'' (``Modeling Guidance'').\76\ The Modeling Guidance
includes recommendations for a modeling protocol, model input
preparation, model performance evaluation, use of model output for the
numerical NAAQS attainment test, and modeling documentation. Air
quality modeling is performed using meteorology and emissions from a
base year, and the predicted concentrations from this base case
modeling are compared to air quality monitoring data from that year to
evaluate model performance.
---------------------------------------------------------------------------

    \76\ Modeling Guidance, EPA 454/R-18-009, November 2018. See
https://www3.epa.gov/ttn/scram/guidance/guide/O3-PM-RH-Modeling_Guidance-2018.pdf. The Modeling Guidance updates, but is
largely consistent with, the earlier ``Guidance on the Use of Models
and Other Analyses for Demonstrating Attainment of Air Quality Goals
for the 8-Hour Ozone and PM2.5 NAAQS and Regional Haze,''
EPA-454/B-07-002, April 2007. Additional EPA modeling guidance can
be found in 40 CFR 51 Appendix W, ``Guideline on Air Quality
Models,'' 82 FR 5182 (January 17, 2017); available at https://www.epa.gov/scram/clean-air-act-permit-modeling-guidance.
---------------------------------------------------------------------------

    Once the model performance is determined to be acceptable, future
year emissions are simulated with the model. The relative (or percent)
change in modeled concentration due to future emissions reductions
provides a relative response factor (RRF). Each monitoring site's RRF
is applied to its monitored base year design value to provide the
future design value for comparison to the NAAQS. The Modeling Guidance
also recommends supplemental air quality analyses, which may be used as
part of a weight of evidence (WOE) analysis. A WOE analysis
corroborates the attainment demonstration by considering evidence other
than the main air quality modeling attainment test, such as trends and
additional monitoring and modeling analyses.
    The Modeling Guidance also does not require a particular year to be
used as the base year for 8-hour ozone plans.\77\ The Modeling Guidance
states that the most recent year of the National Emissions Inventory
may be appropriate

for use as the base year for modeling, but that other years may be more
appropriate when considering meteorology, transport patterns,
exceptional events, or other factors that may vary from year to
year.\78\ Therefore, the base year used for the attainment
demonstration need not be the same year used to meet the requirements
for emissions inventories and RFP.
---------------------------------------------------------------------------

    \77\ Modeling Guidance at section 2.7.1, 35.
    \78\ Id.
---------------------------------------------------------------------------

    With respect to the list of adopted measures, CAA section 172(c)(6)
requires that nonattainment area plans include enforceable emissions
limitations, and such other control measures, means or techniques
(including economic incentives such as fees, marketable permits, and
auctions of emission rights), as well as schedules and timetables for
compliance, as may be necessary or appropriate to provide for timely
attainment of the NAAQS.\79\ Under the 2008 Ozone SRR, all control
measures needed for attainment must be implemented no later than the
beginning of the attainment year ozone season.\80\ The attainment year
ozone season is defined as the ozone season immediately preceding a
nonattainment area's maximum attainment date.\81\
---------------------------------------------------------------------------

    \79\ See also CAA section 110(a)(2)(A).
    \80\ 40 CFR 51.1108(d).
    \81\ 40 CFR 51.1100(h).
---------------------------------------------------------------------------

2. Summary of the State's Submission
a. Photochemical Modeling
    The 2016 Coachella Valley Ozone SIP includes photochemical modeling
for the 2008 ozone NAAQS. The SCAQMD performed the air quality modeling
for the 2016 Coachella Valley Ozone SIP. The modeling relies on a 2012
base year and demonstrates attainment of the 2008 ozone NAAQS in 2026.
    As a general matter, the modeling for the 2016 Coachella Valley
Ozone SIP represents an update to the photochemical modeling performed
for the EPA-approved 2012 AQMP to account for more recent satellite-
based input data, improved chemical gaseous and particulate mechanisms,
improved computational resources and post-processing utilities,
enhanced spatial and temporal allocations of the emissions inventory,
and a revised attainment demonstration methodology. The modeling and
modeled attainment demonstration are described in Chapter 5 (``Future
Air Quality'') of the 2016 AQMP. Chapter 7 (``Current and Future Air
Quality: Desert Nonattainment Areas SIP'') provides background
information on the Coachella Valley, as well as the ozone attainment
demonstration. Appendix V (``Modeling and Attainment Demonstration'')
of the 2016 AQMP provides a description of model input preparation
procedures, various model configuration options, and model performance
statistics. The modeling protocol is in Chapter 2 (``Modeling
Protocol'') of Appendix V of the 2016 AQMP and contains all the
elements recommended in the Modeling Guidance. Those include: Selection
of model, time period to model, modeling domain, and model boundary
conditions and initialization procedures; a discussion of emissions
inventory development and other model input preparation procedures;
model performance evaluation procedures; selection of days; and other
details for calculating RRFs. Appendix V of the 2016 AQMP provides the
coordinates of the modeling domain and thoroughly describes the
development of the modeling emissions inventory, including its chemical
speciation, its spatial and temporal allocation, its temperature
dependence, and quality assurance procedures. Appendix C of CARB's
Staff Report for the 2016 AQMP, entitled ``Coachella Valley Weight of
Evidence,'' provides additional information about ozone formation and
trends in the Coachella Valley.
    The modeling analysis used version 5.0.2 of the Community
Multiscale Air Quality (CMAQ) photochemical model, developed by the
EPA. To prepare meteorological input for CMAQ, the Weather and Research
Forecasting model version 3.6 (WRF) from the National Center for
Atmospheric Research was used. CMAQ and WRF are both recognized in the
Modeling Guidance as technically sound, state-of-the-art models. The
areal extent and the horizontal and vertical resolution used in these
models were adequate for modeling Coachella Valley ozone.
    The WRF meteorological model results and performance statistics are
described in Chapter 3 (``Meteorological Modeling and Sensitivity
Analyses'') of Appendix V. The District evaluated the performance of
the WRF model through a series of simulations and concluded that the
daily WRF simulation for 2012 provided representative meteorological
fields that well characterized the observed conditions. The District's
conclusions were supported by hourly time series graphs of wind speed,
direction, and temperature for the southern California domain, included
as Attachment 1 (``WRF Model Performance Time Series'') to Appendix V.
    Ozone model performance statistics are described in the 2016 AQMP
Appendix V, Chapter 5 (``8-Hour Ozone Attainment Demonstration'') which
include tables of statistics recommended in the Modeling Guidance for
ozone for the South Coast sub-regions, including the Coachella
Valley.\82\ Hourly time series are presented as well as density scatter
plots, and plots of bias against concentration. Note that, because only
relative changes are used from the modeling, the underprediction of
ozone concentrations does not mean that future concentrations will be
underestimated.
---------------------------------------------------------------------------

    \82\ The other sub-regions are the ``Coastal,'' ``San
Fernando,'' ``Foothills,'' ``Urban Source,'' and ``Urban Receptor''
zones.
---------------------------------------------------------------------------

    After model performance for the 2012 base case was accepted, the
model was applied to develop RRFs for the attainment demonstration.
This entailed running the model with the same meteorological inputs as
before, but with adjusted emissions inventories to reflect the expected
changes between 2012 and the 2026 attainment year. The base year or
``reference year'' modeling inventory was the same as the inventory for
the modeling base case. The 2026 inventory projects the base year into
the future by including the effect of economic growth and emissions
control measures. The set of 153 days from May 1 through September 30,
2012, was simulated and analyzed to determine 8-hour average maximum
ozone concentrations for the 2012 and 2026 emissions inventories. To
develop the RRFs for the 8-hour ozone NAAQS, only the top 10 days were
used, consistent with the Modeling Guidance.\83\
---------------------------------------------------------------------------

    \83\ See Modeling Guidance at section 4.2.1.
---------------------------------------------------------------------------

    The Modeling Guidance addresses attainment demonstrations with
ozone NAAQS based on 8-hour averages, and for the 2008 ozone NAAQS, the
2016 AQMP carried out the attainment test procedure consistent with the
Modeling Guidance. The RRFs were calculated as the ratio of future to
base year concentrations. The resulting RRFs were then applied to 2012
weighted base year design values \84\ for each monitor to arrive at
2026 future year design values. Ozone is measured continuously at two
locations in the Coachella Valley at the Palm Springs and Indio air
monitoring stations. The modeled 2026 ozone design value at the Palm
Springs site (the higher of the two sites) is 0.075 ppm; this value
demonstrates attainment of the 2008 ozone NAAQS.\85\
---------------------------------------------------------------------------

    \84\ The Modeling Guidance recommends that RRFs be applied to
the average of three three-year design values centered on the base
year, in this case the design values for 2010-2012, 2011-2013, and
2012-2014. This amounts to a 5-year weighted average of individual
year 4th high concentrations, centered on the base year of 2012, and
so is referred to as a weighted design value.
    \85\ 2016 AQMP, Appendix V, page V-5-28.

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

    The 2016 AQMP modeling includes a WOE demonstration, based on a
model performance evaluation of the temporal profile of on-road mobile
source emissions and spatial surrogate profiles of area emissions.\86\
The demonstration is based on a sensitivity analysis of four scenarios
of emissions reductions. Appendix C of CARB's Staff Report for the 2016
AQMP also provides a WOE discussion that includes information about
ozone formation in the Coachella Valley. The WOE demonstration in
Appendix C includes ambient ozone data and trends, precursor emissions
trends and reductions, and population exposure trends to complement the
regional photochemical modeling analyses.
---------------------------------------------------------------------------

    \86\ 2016 AQMP, Appendix V, pages V-5-36 to V-5-41.
---------------------------------------------------------------------------

b. Control Strategy for the 2008 Ozone NAAQS
    The control strategy for attainment of the 2008 ozone NAAQS in the
Coachella Valley relies primarily on timely attainment in 2023 of the
1997 ozone NAAQS in the South Coast. Continued air quality improvement
in the Coachella Valley is expected during the 2023 through 2026
timeframe because of ongoing fleet turnover in the Coachella Valley and
South Coast and from existing measures and additional reductions from
new measures implemented before 2027 for attainment of the 2008 ozone
NAAQS by 2031 in the South Coast.
    The control strategy in the 2016 South Coast Ozone SIP for
attainment of the 1997 ozone NAAQS by 2023 in the South Coast relies on
emissions reductions from already-adopted measures, commitments by the
District to certain regulatory and nonregulatory initiatives and
aggregate emissions reductions, and commitments by CARB to certain
regulatory and nonregulatory initiatives and aggregate emissions
reductions. Already-adopted measures are expected to achieve
approximately 66 percent of the NOX reductions needed from
the 2012 base year for the South Coast to attain the NAAQS in 2023. To
address the remaining emissions reductions, the 2016 South Coast Ozone
SIP includes District and CARB aggregate commitments to achieve
additional emissions reductions by 2023, as shown in tables 2, 3, and 4
below. Table 2 summarizes the additional reduction commitments in the
2016 South Coast Ozone SIP. Tables 3 and 4 show the District and CARB
measures included in the aggregate commitments in Table 2. The
emissions reductions for individual measures shown in tables 3 and 4
are not intended to be enforceable; they are estimates prepared by the
District and CARB to show how they expect at the present time to
achieve the aggregate emissions reductions for 2023. The EPA's June 17,
2019 proposed approval of the 2016 South Coast Ozone SIP provides an
extensive discussion of the control strategy and attainment
demonstrations for the upwind South Coast to attain the 1997 and 2008
ozone NAAQS.\87\
---------------------------------------------------------------------------

    \87\ 84 FR 28132.

 Table 2--District and CARB Aggregate Emission Reduction Commitments for
                   2023 in 2016 South Coast Ozone Plan
                   [Summer planning inventory, tpd] a
------------------------------------------------------------------------
                                                     Year 2023
                  Plan                   -------------------------------
                                                NOX             VOC
------------------------------------------------------------------------
SCAQMD b................................              23               6
CARB c..................................             113           50-51
                                         -------------------------------
    Total...............................             136           56-57
------------------------------------------------------------------------
\a\ Rounded to whole number.
\b\ 2016 AQMP, tables 4-9, 4-10 and 4-11. Reductions are from the 2012
  base year.
\c\ 2016 State Strategy, Table 4, and CARB Resolution 17-7 (March 23,
  2017). Reductions are from the 2012 base year.

                                             Table 3--District Measures With Reductions by 2023 in 2016 AQMP
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                NOX Emission
                                                                                Reductions     VOC emission
                   No.                                 Title                Adoption          Implementation period            (tpd)        reductions
                                                                                (tpd)
--------------------------------------------------------------------------------------------------------------------------------------------------------
CMB-01...................................  Transition to Zero and Near-            2018  Ongoing........................             2.5         \a\ 1.2
                                            Zero Emission Technologies
                                            for Stationary Sources.
CMB-02...................................  Emission Reductions from                2018  2020-2031......................             1.1  ..............
                                            Replacement with Zero or
                                            Near-Zero NOX Appliances in
                                            Commercial and Residential
                                            Applications
CMB-03...................................  Emission Reductions from Non-           2018  2020...........................             1.4         \a\ 0.4
                                            Refinery Flares.
CMB-04...................................  Emission Reductions from                2018  2022...........................             0.8  ..............
                                            Restaurant Burners and
                                            Residential Cooking.
BCM-10...................................  Emission Reductions from                2019  2020...........................  ..............             1.5
                                            Greenwaste Composting.
FUG-01...................................  Improved Leak Detection and             2019  2022...........................  ..............             2.0
                                            Repair.
CTS-01...................................  Further Emission Reductions        2017/2021  2020-2031......................  ..............             1.0
                                            from Coatings, Solvents,
                                            Adhesives, and Sealants.
ECC-02...................................  Co-Benefits from Existing               2018  Ongoing........................             0.3         \a\ 0.1
                                            Residential and Commercial
                                            Building Energy Efficiency
                                            Measures
ECC-03...................................  Additional Enhancements in              2018  Ongoing........................             1.2         \a\ 0.2
                                            Reducing Existing
                                            Residential Building Energy
                                            Use.
                                          --------------------------------------------------------------------------------------------------------------
    Stationary Sources Totals...........................................................................................             7.3             6.4

MOB-10...................................  Extension of the SOON \b\                 NA  Ongoing........................             1.9  ..............
                                            Provision for Construction/
                                            Industrial Equipment.
MOB-11...................................  Extended Exchange Program...              NA  Ongoing........................             2.9  ..............
MOB-14...................................  Emission Reductions from                  NA  2016-2024......................              11  ..............
                                            Incentive Programs.
                                          --------------------------------------------------------------------------------------------------------------
    Mobile Sources Totals...............................................................................................            15.8  ..............
        Stationary and Mobile Sources Totals............................................................................            23.1             6.4
--------------------------------------------------------------------------------------------------------------------------------------------------------
Notes:
\a\ Corresponding VOC reductions from other measures.
\b\ Surplus Off-Road Opt-In for NOX Program
 The sum of the emissions values may not equal the total shown due to rounding of the numbers.
Source: 2016 AQMP, tables 4-2, 4-4, 4-9, 4-10 and 4-11.

                                         Table 4--Measures With Reductions by 2023 in CARB's 2016 State Strategy
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                Implementation                  NOX Emission
                                                                           ----------------------------------------------   Reductions     VOC emission
                  Title                                Adoption                                                                (tpd)        reductions
                                                                              Time frame               Agency                                  (tpd)
--------------------------------------------------------------------------------------------------------------------------------------------------------
On-Road Light-Duty:
    Further Deployment of Cleaner          ongoing........................            2016  CARB, SCAQMD, EPA...........               7              16
     Technologies \a\.
On-Road Heavy-Duty:
    Lower In-Use Emission Performance      2017-2020......................          2018 +  CARB........................             NYQ            <0.1
     Level.
    Innovative Clean Transit.............  2017...........................            2018  CARB........................            <0.1            <0.1
    Last Mile Delivery...................  2018...........................            2020  CARB........................            <0.1            <0.1
    Incentive Funding to Achieve Further   ongoing........................            2016  CARB, SCAQMD................               3             0.4
     Emission Reductions from On-Road
     Heavy Duty Vehicles \b\.
    Further Deployment of Cleaner          ongoing........................            2016  CARB, SCAQMD, EPA...........              34               4
     Technologies \a\.
Aircraft:
    Further Deployment of Cleaner          ongoing........................            2016  CARB, SCAQMD, EPA...........               9             NYQ
     Technologies \a\.
Locomotives:
    More Stringent National Locomotive     2017...........................            2023  EPA.........................            <0.1            <0.1
     Emission Standards.
    Further Deployment of Cleaner          ongoing........................            2016  CARB, SCAQMD, EPA...........               7             0.3
     Technologies \a\.
Ocean-Going Vessels:
    At-Berth Regulation Amendments.......  2017-2018......................            2023  CARB........................             0.3            <0.1
    Further Deployment of Cleaner          ongoing........................            2016  CARB, SCAQMD, EPA...........              30             NYQ
     Technologies \a\.
Off-Road Equipment:
    Zero-Emission Airport Ground Support   2018...........................            2023  CARB........................            <0.1            <0.1
     Equipment.
    Small Off-Road Engines...............  2018-2020......................            2022  CARB........................             0.7               7
    Low-Emission Diesel Requirement......  by 2020........................            2023  CARB........................             0.3             NYQ
    Further Deployment of Cleaner          ongoing........................            2016  CARB, SCAQMD, EPA...........              21              21
     Technologies \a\.
Consumer Products:
    Consumer Products Program............  2019-2021......................          2020 +  CARB........................               0             1-2
rrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrr
        Total Emission Reductions........  ...............................  ..............  ............................             113           50-51
--------------------------------------------------------------------------------------------------------------------------------------------------------
Notes:
\a\ CARB requested the EPA approve the ``Further Deployment of Cleaner Technologies'' measures under the provisions of section 182(e)(5) of the CAA. In
  today's action we also refer to these as new technology measures.
\b\ On March 22, 2018, CARB adopted the ``South Coast On-Road Heavy-Duty Vehicle Incentive Measure.'' On April 25, 2019, the EPA proposed to approve the
  measure as achieving 1 tpd of NOX reductions in 2023. See 84 FR 17365.
NYQ means not yet quantified.
The sum of the emissions values may not equal the total shown due to rounding of the numbers.
Source: 2016 State Strategy, Table 4; Attachment A to CARB Resolution 17-7 (March 23, 2017).

c. Attainment Demonstration
    Chapter 7 of the 2016 AQMP includes a section entitled ``Ozone
Attainment Demonstration and Projections,'' which describes the
Coachella Valley's progress toward attaining the 1997, 2008, and 2015
ozone standards.\88\ For the 2008 ozone NAAQS, the 2016 AQMP summarizes
the District's modeling for the area, and concludes that the measures
included in the control strategy (including CARB

commitments) will result in the area attaining the standards no later
than 2026. The WOE discussion in Appendix C of CARB's Staff Report for
the 2016 AQMP provides additional discussion of air quality trends and
projections in the Coachella Valley and determines that the area is on
track to attain the 2008 ozone NAAQS by 2026.
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    \88\ 2016 AQMP, 7-35 to 7-40.
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3. The EPA's Review of the State's Submission
a. Photochemical Modeling
    As discussed above in Section III.A of this notice, we are
proposing to approve the base year emissions inventory and to find that
the future year emissions projections in the 2016 AQMP reflect
appropriate calculation methods and that the latest planning
assumptions are properly supported by SIP-approved stationary and
mobile source measures. In the discussion below, we address our
findings for the modeling submitted with the 2016 Coachella Valley
Ozone SIP. Because of the importance of ozone transport from the South
Coast to attainment in the Coachella Valley, and the close interactions
of the modeling for each area, we have considered the modeling for both
areas. Similar and additional discussion for the South Coast can be
found in our June 17, 2019 proposed action on the 2016 South Coast
Ozone SIP.\89\
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    \89\ 84 FR 28132.
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    Based on our review of Appendix V of the 2016 AQMP, the EPA finds
that the photochemical modeling is adequate for purposes of supporting
the attainment demonstration.\90\ First, we note the extensive
discussion of modeling procedures, tests, and performance analyses
called for in the Modeling Protocol (i.e., Chapter 2 of Appendix V of
the 2016 AQMP) and the good model performance. Second, we find the WRF
meteorological model results and performance statistics, including
hourly time series graphs of wind speed, direction, and temperature for
both the South Coast and the Coachella Valley, to be satisfactory and
consistent with our Modeling Guidance.\91\ Performance was evaluated
for each month in each zone for the entire year of 2012.\92\ Diurnal
variation of temperature, humidity and surface wind are well
represented by WRF. Geographically, winds are predicted most accurately
at the inland urban receptor sites. Accurate wind predictions in this
region of elevated ozone concentrations is one of the most critical
factors to simulate chemical transport to the Coachella Valley.
Overall, the daily WRF simulation for 2012 provided representative
meteorological fields that characterized the observed conditions well.
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    \90\ The EPA's review of the modeling and attainment
demonstration is discussed in greater detail in section VI of the
TSD (``Modeling and Attainment Demonstration'').
    \91\ Modeling Guidance, 30.
    \92\ Temperature, water vapor mixing ratio, and wind speed were
evaluated in terms of normalized gross bias and normalized gross
error.
---------------------------------------------------------------------------

    The model performance statistics for ozone are described in Chapter
5 of Appendix V and are based on the statistical evaluation recommended
in the Modeling Guidance. Model performance was provided for 8-hour
daily maximum ozone for Coachella Valley as well as other areas in the
Southern California modeling domain.\93\ A geographical bias is shown
in the time series, with over-prediction in coastal areas, and under-
prediction in the inland areas, including Coachella Valley.\94\ The
2016 AQMP also presents ozone frequency distributions, scatter plots,
and plots of bias against concentration. The scatter and density
scatter plots show low bias at high concentrations, and higher bias at
low concentrations. The low bias at high concentrations is important
because it reflects the model's capability to predict high
concentrations, in particular, the top 10 days that form the basis for
the RRF calculation. The supplemental hourly time series show generally
good performance, though many individual daily ozone peaks are
underpredicted. As noted above, however, the underprediction of
absolute ozone concentrations does not mean that future concentrations
will be underestimated. In addition, the WOE analysis presented in
Appendix C of CARB's Staff Report for the 2016 Coachella Valley Ozone
SIP provides additional information with respect to the sensitivity to
emissions changes and further supports the model performance. We are
proposing to find the air quality modeling adequate to support the
attainment demonstration for the 2008 ozone NAAQS, based on reasonable
meteorological and ozone modeling performance, and supported by the
weight of evidence analyses. For additional information, please see
section VI of the TSD for this action.
---------------------------------------------------------------------------

    \93\ 2016 AQMP Appendix V, Table V-5-8. These zones are
represented by the following ozone monitoring sites: ``Coastal''
(Costa Mesa, LAX, Long Beach, Mission Viejo, West Los Angeles);
``Urban Source'' (Anaheim, Central Los Angeles, Compton, La Habra,
Pico Rivera, Pomona); ``San Fernando'' (Reseda, Santa Clarita,
Burbank); ``Foothills'' (Azusa, Glendora, Pasadena); ``Urban
Receptor'' (Crestline, Fontana, Lake Elsinore, Mira Loma, Redlands,
Rubidoux, San Bernardino, Upland); and ``Coachella Valley'' (Palm
Springs and Indio).
    \94\ The model performance varied by zone, with over-prediction
in the ``Coastal'' zone and under-prediction in the ``San
Fernando,'' and ``Foothills'' zones. The model ozone predictions in
the ``Urban Receptor'' zone agree reasonably well with the
measurements.
---------------------------------------------------------------------------

b. Control Strategy
    The Coachella Valley control strategy relies primarily on
previously adopted and future emissions reductions detailed in the 2016
South Coast Ozone SIP. As described in Section III.D.2.b above, a
significant portion of the emissions reductions needed to attain the
1997 ozone NAAQS in the South Coast by 2023 will be obtained through
previously adopted measures in the SIP, and the balance of the
reductions needed for attainment will result from enforceable
commitments to take certain specific actions within prescribed periods
and to achieve aggregate tonnage reductions of VOC or NOX by
specific years. The aggregate commitments provide the remaining
additional upwind reductions necessary for the Coachella Valley to
attain the 2008 ozone NAAQS by 2026. In our October 1, 2019 approval of
the 2016 South Coast Ozone SIP, the EPA approved the control strategy,
including CARB's and the District's aggregate commitments, for the
South Coast to attain the 1997 ozone NAAQS.\95\ For the reasons
described in that action, and based on the District's demonstration
specific to the Coachella Valley described above, we propose to find
the District's control strategy acceptable for purposes of attaining
the 2008 ozone NAAQS in the Coachella Valley. For additional
information, please see the TSD for this action.
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    \95\ See 84 FR 52005.
---------------------------------------------------------------------------

c. Attainment Demonstration
    Based on our proposed determinations that the photochemical
modeling and control strategy are acceptable, we propose to approve the
attainment demonstration for the 2008 ozone NAAQS in the 2016 Coachella
Valley Ozone SIP as meeting the requirements of CAA section
182(c)(2)(A) and 40 CFR 51.1108.

E. Rate of Progress Plan and Reasonable Further Progress Demonstration

1. Statutory and Regulatory Requirements
    Requirements for RFP for ozone nonattainment areas are specified in
CAA sections 172(c)(2), 182(b)(1), and 182(c)(2)(B). Under CAA section
171(1), RFP is defined as meaning such annual incremental reductions in
emissions of the relevant air pollutant as are required under part D
(``Plan Requirements for Nonattainment Areas'') of the CAA or as may
reasonably be required by the EPA

for the purpose of ensuring attainment of the applicable NAAQS by the
applicable date. CAA section 182(b)(1) specifically requires that ozone
nonattainment areas classified as Moderate or above demonstrate a 15
percent reduction in VOC between the years of 1990 and 1996. The EPA
has typically referred to section 182(b)(1) as the rate of progress
(ROP) requirement. For ozone nonattainment areas classified as Serious
or higher, section 182(c)(2)(B) requires VOC reductions of at least 3
percent of baseline emissions per year, averaged over each consecutive
3-year period, beginning 6 years after the baseline year until the
attainment date. Under CAA section 182(c)(2)(C), a state may substitute
NOX emissions reductions for VOC emissions reductions.
Additionally, CAA section 182(c)(2)(B)(ii) allows an amount less than 3
percent of such baseline emissions each year if a state demonstrates to
the EPA that its plan includes all measures that can feasibly be
implemented in the area in light of technological achievability.
    In the 2008 Ozone SRR, the EPA provides that areas classified
Moderate or higher will have met the ROP requirements of CAA section
182(b)(1) if the area has a fully approved 15 percent ROP plan for the
1-hour or 1997 ozone NAAQS.\96\ For such areas, the EPA interprets the
RFP requirements of CAA section 172(c)(2) to require areas classified
as Moderate to provide a 15 percent emissions reduction of ozone
precursors within 6 years of the baseline year. Areas classified as
Serious or higher must meet the RFP requirements of CAA section
182(c)(2)(B) by providing an 18 percent reduction of ozone precursors
in the first 6-year period, and an average ozone precursor emissions
reduction of 3 percent per year for all remaining 3-year periods
thereafter.\97\ The 2008 Ozone SRR allows substitution of
NOX reductions for VOC reductions to meet the CAA section
172(c)(2) and 182(c)(2)(B) RFP requirements.\98\
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    \96\ 70 FR 12264, 12271 (March 6, 2015).
    \97\ Id.
    \98\ Id.; 40 CFR 51.1110(a)(2)(i)(C) and 40 CFR
51.1110(a)(2)(ii)(B).
---------------------------------------------------------------------------

    Except as specifically provided in CAA section 182(b)(1)(C),
emissions reductions from all SIP-approved, federally promulgated, or
otherwise SIP-creditable measures that occur after the baseline year
are creditable for purposes of demonstrating that the RFP targets are
met. Because the EPA has determined that the passage of time has caused
the effect of certain exclusions to be de minimis, the RFP
demonstration is no longer required to calculate and specifically
exclude reductions from measures related to motor vehicle exhaust or
evaporative emissions promulgated by January 1, 1990; regulations
concerning Reid vapor pressure promulgated by November 15, 1990;
measures to correct previous RACT requirements; and measures required
to correct previous inspection and maintenance (I/M) programs.\99\
---------------------------------------------------------------------------

    \99\ 40 CFR 51.1110(a)(7).
---------------------------------------------------------------------------

    The 2008 Ozone SRR requires the RFP baseline year to be the most
recent calendar year for which a complete triennial inventory was
required to be submitted to the EPA. For the purposes of developing RFP
demonstrations for the 2008 ozone NAAQS, the applicable triennial
inventory year is 2011. As discussed previously, the 2008 Ozone SRR
provided states with the opportunity to use an alternative baseline
year for RFP,\100\ but that provision of the 2008 Ozone SRR was vacated
by the D.C. Circuit in the South Coast II decision.
---------------------------------------------------------------------------

    \100\ 40 CFR 51.1110(b).
---------------------------------------------------------------------------

2. Summary of the State's Submission
    In response to the South Coast II decision, CARB developed the 2018
SIP Update to revise the RFP demonstrations in previously submitted
ozone SIPs, including the Coachella Valley RFP demonstration in the
2016 AQMP. The 2018 SIP Update includes updated emissions estimates for
the 2011 RFP baseline year, subsequent milestone years, and the
attainment year.\101\ To develop the 2011 RFP baseline inventory, CARB
relied on actual emissions reported from industrial point sources for
year 2011 and backcast emissions from smaller stationary sources and
area sources from 2012 to 2011 using the same growth and control
factors as was used for the 2016 AQMP. To develop the emissions
inventories for the RFP milestone years (i.e., 2017, 2020, 2023) and
attainment year (2026), CARB also relied upon the same growth and
control factors as the 2016 AQMP.\102\ For both sets of baseline
emissions inventories (those in the 2016 AQMP and those in the 2018 SIP
Update), emissions estimates reflect District rules adopted through
December 2015 and CARB rules adopted through November 2015.
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    \101\ 2018 SIP Update, RFP demonstration, section IX-B, 44 and
45.
    \102\ Documentation for the Coachella Valley RFP baseline and
milestone emissions inventories is found in the 2018 SIP Update on
pages 4-5, 44-45, and Appendix A, pages A-23 to A-26.
---------------------------------------------------------------------------

    The updated RFP demonstration for Coachella Valley for the 2008
ozone NAAQS is shown in Table 5. The updated RFP demonstration
calculates future year VOC targets from the 2011 baseline, consistent
with CAA 182(c)(2)(B)(i), which requires reductions of ``at least 3
percent of baseline emissions each year,'' and it substitutes
NOX reductions for VOC reductions beginning in milestone
year 2020 to meet VOC emission targets.\103\ For the Coachella Valley,
CARB concludes that the RFP demonstration meets the applicable
requirements for each milestone year as well as the attainment year.
---------------------------------------------------------------------------

    \103\ NOX substitution is permitted under EPA
regulations. See 40 CFR 51.1110(a)(2)(i)(C) and 40 CFR
51.1110(a)(2)(ii)(B); and 70 FR 12264, at 12271 (March 6, 2015).

                                      Table 5--RFP Demonstration for the Coachella Valley for the 2008 Ozone NAAQS
                                                       [Summer planning inventory, tpd or percent]
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                VOC
                                   ---------------------------------------------------------------------------------------------------------------------
                                         2011                 2017                      2020                      2023                     2026
--------------------------------------------------------------------------------------------------------------------------------------------------------
Baseline VOC......................            16.9  14.8....................  14.5....................  14.7...................  15.1
Required change since 2011 (VOC or  ..............  18%.....................  27%.....................  36%....................  45%
 NOX), %.
Required reductions since 2011....  ..............  3.0.....................  4.6.....................  6.1....................  7.6
Target VOC level..................  ..............  13.9....................  12.3....................  10.8...................  9.3
Apparent shortfall in VOC.........  ..............  -0.9....................  -2.2....................  -3.9...................  -5.8
Apparent shortfall in VOC, %......  ..............  -5.6%...................  -13.0%..................  -23.0%.................  -34.1%
VOC shortfall previously provided   ..............  0.0%....................  5.6%....................  13.0%..................  23.0%
 by NOX substitution, %.
Actual VOC shortfall, %...........  ..............  -5.6%...................  -7.5%...................  -10.0%.................  -11.1%
                                   ---------------------------------------------------------------------------------------------------------------------

                                                                                NOX
rrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrr
Baseline NOX......................            29.8  18.1....................  14.9....................  10.2...................  9.1
Change in NOX since 2011..........  ..............  11.8....................  15.0....................  19.6...................  20.7