SOX, and VOC emissions do not contribute significantly to
PM2.5 levels that exceed the 2012 annual PM2.5
NAAQS in the SJV, as discussed in section IV.B of this proposed rule,
the RFP demonstration provided by the State addresses emissions of
direct PM2.5 and NOX.\273\ Similarly, the State
developed quantitative milestones based upon the Plan's control
strategy measures that achieve emission reductions of direct
PM2.5 and NOX.\274\ For the 2012 annual
PM2.5 NAAQS, the RFP demonstration in the Plan follows a
stepwise approach due to the time required for CARB and the District
``to amend rules, develop programs, and implement the emission
reduction measures.'' \275\ The revised Appendix H provides clarifying
information on the RFP demonstration, including additional information
to justify the Plan's stepwise approach to demonstrating RFP. This
clarifying information did not affect the Plan's quantitative
milestones. We describe the RFP demonstration and quantitative
milestones in the SJV PM2.5 Plan in greater detail below.
---------------------------------------------------------------------------

    \272\ Appendix H to 2018 PM2.5 Plan, submitted
February 11, 2020, via the EPA State Planning Electronic
Collaboration System. This revised version of Appendix H replaces
the version submitted with the 2018 PM2.5 Plan on May 10,
2019. All references to Appendix H in this proposed rule are to the
revised version of Appendix H submitted February 11, 2020.
    \273\ 2018 PM2.5 Plan, App. H, H-1.
    \274\ Id. at App. H, H-23 to H-24 (for CARB milestones) and H-20
to H-22 (for District milestones).
    \275\ Id. at App. H, H-4.
---------------------------------------------------------------------------

(a) Reasonable Further Progress
    The State addressed the RFP and quantitative milestone requirements
in Appendix H to the 2018 PM2.5 Plan submitted in February
2020. The State estimates that emissions of direct PM2.5 and
NOX will generally decline from the 2013 base year to the
projected 2025 attainment year. The Plan's emissions inventory shows
that direct PM2.5 and NOX are emitted by a large
number and range of sources in the SJV. Table H-2 in Appendix H
contains an anticipated implementation schedule for District

regulatory control measures and Table 4-8 in Chapter 4 of the 2018
PM2.5 Plan contains an anticipated implementation schedule
for CARB control measures in the SJV. Table H-5 in Appendix H
(reproduced in Table 6 of this proposed rule) contains projected
emissions for each quantitative milestone year and the attainment year.
These emission levels reflect both baseline emissions projections and
commitments to achieve additional emission reductions through
implementation of new control measures by 2025.\276\
---------------------------------------------------------------------------

    \276\ In App. H, see tables H-3 (emission projections based on
baseline measures) and H-4 (reductions from control measure
commitments). The SJV PM2.5 Plan includes commitments for
reductions from new control measures by 2024 and 2025.

   Table 6--PM2.5 Projected Emissions Inventory for Base and Milestone Years, Including Baseline Measures and
                                         Emission Reduction Commitments
                                              [Annual average, tpd]
----------------------------------------------------------------------------------------------------------------
                                                       2013          2019 \a\          2022            2025
----------------------------------------------------------------------------------------------------------------
                                                                                Quantitative
                                                                   Quantitative    Quantitative    milestone and
                    Pollutant                      Baseline year     milestone       milestone      attainment
                                                                                year
----------------------------------------------------------------------------------------------------------------
PM2.5...........................................            62.5            59.2            58.4            56.1
NOX.............................................           317.2           214.5           179.8           109.8
----------------------------------------------------------------------------------------------------------------
Source: 2018 PM2.5 Plan, Appendix H, Table H-5.
\a\ 2019 is a quantitative milestone year in the SJV for the 2012 annual PM2.5 NAAQS for purposes of CAA
  requirements for Moderate PM2.5 nonattainment areas.

    Table H-6 and Table H-7 of Appendix H (reproduced in Table 7 of
this proposed rule) identify the reductions needed for attainment of
the 2012 annual PM2.5 NAAQS by 2025, and the SJV's projected
progress toward attainment in each milestone year.

             Table 7--Emission Reductions Needed for Attainment and Achieved in Each Milestone Year
                                                [Annual average]
----------------------------------------------------------------------------------------------------------------
                                                                   Percent reductions achieved in milestone year
                                                    Reductions   -----------------------------------------------
                                                    needed for         2019            2022            2025
                    Pollutant                       attainment   -----------------------------------------------
                                                    (from 2013     Quantitative    Quantitative     Attainment
                                                     baseline)       milestone       milestone         year
----------------------------------------------------------------------------------------------------------------
PM2.5...........................................         6.4 tpd            51.6            64.1             100
NOX.............................................       207.4 tpd            49.5            66.2             100
----------------------------------------------------------------------------------------------------------------
Source: 2018 PM2.5 Plan, Appendix H, tables H-6 and H-7.

    Based on the data in tables 6 and 7 of this proposed rule, CARB and
the District set RFP targets for the attainment year and quantitative
milestone years as shown in Table H-11 of Appendix H (reproduced in
Table 8 of this proposed rule). The targets are consistent with a
stepwise approach to demonstrating RFP. The emission projections show
steady reductions over time. The reductions between the 2013 base year
and the 2019 milestone year (51.6% of the direct PM2.5
reductions and 49.5% of the NOX reductions needed for
attainment), which we evaluated in the context of the Moderate area
requirements for RFP and quantitative milestones, are consistent with a
generally linear approach to demonstrating RFP. Emissions further
decrease by the 2022 milestone year but fall short of the rate of
reductions that would show generally linear progress toward
attainment.\277\ The Plan relies on a more substantial direct
PM2.5 and NOX emission reduction by 2025 due, in
large part, to CARB and the District's commitments to achieve
additional PM2.5 emission reductions from new measures by
2025.
---------------------------------------------------------------------------

    \277\ To show generally linear progress, emissions would need to
decrease by approximately 75% from 2013 to 2022. The projected
decrease for this span of years is 64.1% for direct PM2.5
and 66.2% for NOX.
---------------------------------------------------------------------------

    According to the Plan, reductions in both direct PM2.5
and NOX emissions from 2013 base year levels result in
emissions levels consistent with attainment in the 2025 attainment
year. Based on these analyses, CARB and the District assert that the
adopted control strategy and additional commitments for reductions from
new control programs by 2025 are adequate to meet the RFP requirement
for the 2012 annual PM2.5 NAAQS.

                      Table 8--Stepwise RFP Target Emission Levels and Projected Emission Levels for Milestone and Attainment Years
                                                                  [Annual average, tpd]
--------------------------------------------------------------------------------------------------------------------------------------------------------
                        Pollutant                                      2019                            2022                            2025
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                              Target         Projected        Target         Projected        Target         Projected
--------------------------------------------------------------------------------------------------------------------------------------------------------
PM2.5...................................................            59.2            59.2            58.4            58.4            56.1            56.1

NOX.....................................................           214.5           214.5           179.8           179.8           109.8           109.8
--------------------------------------------------------------------------------------------------------------------------------------------------------
Source: 2018 PM2.5 Plan, Appendix H, Table H-11.

    CARB and the District's control strategy in the 2018
PM2.5 Plan for attaining the 2012 annual PM2.5
NAAQS relies on ongoing reductions from baseline measures and an
aggregate tonnage commitment for the remaining reductions needed for
attainment. The majority of the NOX and PM2.5
reductions needed for attainment result from CARB's current mobile
source control program. The attainment control strategy in the Plan is
projected to achieve total emission reductions of 207.4 tpd
NOX and 6.4 tpd direct PM2.5, of which 78% (162
tpd) and 73% (4.7 tpd), respectively, are attributed to CARB's baseline
mobile source program.\278\ These on-going controls will thus result in
additional reductions in NOX and direct PM2.5
emissions between the 2013 base year and 2025 attainment year.\279\
---------------------------------------------------------------------------

    \278\ Id. at Ch. 4, Table 4-7.
    \279\ Id. at App. H, H-4.
---------------------------------------------------------------------------

    CARB's mobile source control program provides significant ongoing
reductions in emissions of direct PM2.5 and NOX
from on-road and non-road mobile sources such as light duty vehicles,
heavy-duty trucks and buses, non-road equipment, and fuels. For on-road
and non-road mobile sources, which represent the largest sources of
NOX emissions in the SJV, Appendix H of the 2018
PM2.5 Plan identifies five mobile source regulations and
control programs that limit emissions of direct PM2.5 and
NOX: The On-Road Heavy-Duty Diesel Vehicles (In-Use)
Regulation (``Truck and Bus Regulation''), the In-Use Off-Road Diesel-
Fueled Fleets Regulation (``Off-Road Regulation''), the California Low-
NOX Engine Standard for new on-road heavy-duty engines used
in medium- and heavy-duty trucks purchased in California, Heavy-Duty I/
M, and the second phase of the Advanced Clean Cars Program (``ACC
2'').\280\ CARB's mobile source BACM analysis in Appendix D of the 2018
PM2.5 Plan provides a more comprehensive overview of each of
these programs and regulations, among many others.\281\ CARB's emission
projections for mobile sources are presented in the Plan's emissions
inventory.\282\
---------------------------------------------------------------------------

    \280\ 2018 PM2.5 Plan, App. H, H-21 and H-22. Because
the ACC 2 measure is not scheduled for implementation until 2026
(see 2018 PM2.5 Plan, Table 4-8), which is after the
January 1, 2025 implementation deadline under 40 CFR 51.1011(b)(5)
for control measures necessary for attainment by December 31, 2025,
we are not reviewing this program as part of the control strategy in
the SJV PM2.5 Plan.
    \281\ 2018 PM2.5 Plan, App. D, Ch. IV.
    \282\ 2018 PM2.5 Plan, App. B.
---------------------------------------------------------------------------

    The Truck and Bus Regulation, first adopted in 2008 and amended in
2011, has rolling compliance deadlines based on truck engine model year
(MY). CARB's implementation of the Truck and Bus Regulation includes
phase-in requirements for PM2.5 and NOX emissions
reductions that began in 2012 and require nearly all pre-2010 vehicles
to have exhaust emissions meeting 2010 MY engine emission levels by
2023.\283\ The 2010 MY engines include particulate filters for direct
PM2.5 control. By 2016, the particulate filter requirement
for trucks with a gross vehicle weight rating greater than 26,001
pounds was fully implemented in the SJV and all heavier trucks with
1995 and older model year engines were required to have a 2010 engine
installed or to be replaced by a truck with a 2010 MY engine.\284\
---------------------------------------------------------------------------

    \283\ The State's quantitative milestone report for the 2019
milestone indicates that the requirement for heavier trucks to
install diesel particulate filters was fully implemented by 2016.
CARB and SJVUAPCD, ``2019 Quantitative Milestone Report for the 2012
PM2.5 NAAQS,'' 7, submitted by letter dated January 13,
2020, from Richard W. Corey, Executive Officer, CARB, to Mike
Stoker, Regional Administrator, EPA Region IX, with enclosures, 7.
    \284\ Id.
---------------------------------------------------------------------------

    For non-road vehicles, CARB adopted the Off-Road Regulation in 2007
to regulate vehicles used in construction, mining, and other industrial
applications. The Off-Road Regulation requires owners to (1) replace
older engines or vehicles with newer, cleaner models, (2) retire older
vehicles or reduce their use, or (3) apply retrofit exhaust
controls.\285\ Beginning in 2014 for large fleets and in 2017 for
medium fleets, non-road fleets are required to meet increasingly
stringent fleet average indices over time.\286\ These indices reflect a
fleet's overall PM and NOX emissions rates by model year and
horsepower.
---------------------------------------------------------------------------

    \285\ 2019 QM Report, 9.
    \286\ A fleet average index is an indicator of a fleet's overall
emissions rate of particulate matter and NOX based on the
horsepower and model year of each engine in the fleet.
---------------------------------------------------------------------------

    The District has also adopted numerous stationary and area source
rules for direct PM2.5 and NOX emission sources
that are projected to contribute to RFP and attainment of the
PM2.5 standards. These include control measures for
stationary internal combustion engines, residential fireplaces, glass
manufacturing facilities, agricultural burning sources, and various
sizes of boilers, steam generators, and process heaters used in
industrial operations. Appendix H of the 2018 PM2.5 Plan
identifies stationary source regulatory control measures implemented by
the District that achieve ongoing PM2.5 and/or
NOX reductions through the Plan's RFP milestone years and
the attainment year.\287\ These measures include seven rule amendments
that the District adopted in 2019 through 2021, as discussed in section
IV.F.3.c of this proposed rule and tabulated in Table IV-B of the EPA's
2012 Annual PM2.5 TSD.
---------------------------------------------------------------------------

    \287\ 2018 PM2.5 Plan, App. H, Table H-2.
---------------------------------------------------------------------------

    With respect to the 2022 milestone year, Rule 4354 was amended in
2011 to lower certain limits on emissions of NOX,
SOX, and PM10 from container glass, flat glass,
and fiberglass manufacturing facilities. Rule 4702 was amended in 2013
to lower the NOX and SOX emission limits for
various types of internal combustion engines rated at 25 brake
horsepower or greater. The District amended Rule 4901 in 2019 to lower
the thresholds at which ``No Burn'' days will be imposed to limit
direct PM2.5 emissions from high-polluting wood burning
heaters and fireplaces during the November through February timeframe
in three ``hot spot'' counties (Fresno, Kern, and Madera), with
implementation beginning November 1, 2019. These rules contribute to
additional emission

reductions of direct PM2.5 and NOX from the 2013
base year to the 2022 RFP milestone year. Additional District measures
to control sources of direct PM2.5 and NOX are
also presented in the Plan's BACM/MSM analyses and reflected in the
Plan's baseline emission projections.\288\
---------------------------------------------------------------------------

    \288\ 2018 PM2.5 Plan, App. B and App. C.
---------------------------------------------------------------------------

    For the remainder of the emission reductions necessary for
attainment, the SJV PM2.5 Plan identifies a series of
additional CARB and District commitments to achieve emission reductions
through additional control measures and incentive programs that will
contribute to attainment of the 2012 annual PM2.5 NAAQS by
2025, as discussed in section IV.F.3.c of this proposed rule. For
mobile sources, CARB's commitment identifies a list of 12 regulatory
measures and 3 incentive-based measures that CARB has committed to
propose to its Board for consideration by specific dates.\289\ For
stationary and area sources, the District's commitment identifies a
list of nine regulatory measures and three incentive-based measures
that the District has committed to propose to its Board for
consideration by specific dates.\290\ Both CARB and the District have
committed to achieve specific amounts of reductions in direct
PM2.5 and NOX emissions by 2025, either through
implementation of these listed measures or through implementation of
other control measures that achieve the necessary amounts of emission
reductions by 2025.\291\
---------------------------------------------------------------------------

    \289\ 2018 PM2.5 Plan, Chapter 4, Table 4-8 and CARB
Resolution 18-49, 5. Table 4-8 of the 2018 PM2.5 Plan
lists 14 State regulatory measures, but we are excluding from our
review the ACC 2 measure and the ``Cleaner In-Use Agricultural
Equipment'' measure because these measures are scheduled for
implementation in 2026 and 2030, respectively, which fall after the
January 1, 2025 implementation deadline for control measures
necessary for attainment by December 31, 2025. 40 CFR 51.1011(b)(5).
    \290\ 2018 PM2.5 Plan, Chapter 4, Table 4-4 and
SJVUAPCD Governing Board Resolution 18-11-16, 10-11.
    \291\ SJVUAPCD Governing Board Resolution 18-11-16, 10-11 and
CARB Resolution 18-49, 5.
---------------------------------------------------------------------------

    The 2018 PM2.5 Plan discusses a number of additional
control measures that the District may adopt to meet its aggregate
tonnage commitment, including additional control requirements for
flares; boilers, steam generators, and process heaters of various
sizes; glass melting furnaces; internal combustion engines;
conservation management practices for agricultural operations; and
commercial under-fired charbroilers.\292\ In addition, the Plan states
that the District intends to use incentive programs to reduce emissions
of direct PM2.5 and NOX from internal combustion
engines used in agricultural operations, commercial under-fired
charbroilers, and residential woodburning devices.\293\ The 2018
PM2.5 Plan establishes deadlines between 2018 and 2023 for
CARB to take action on and begin implementing the 15 additional mobile
source control measures that CARB has committed to propose to its Board
\294\ and similar deadlines between 2019 and 2024 for the District to
take action on and begin implementing the 12 additional District
control measures that the District has committed to propose to its
Board.\295\
---------------------------------------------------------------------------

    \292\ 2018 PM2.5 Plan, Chapter 4, 4-12 and 4-15 to 4-
22.
    \293\ Id. at 4-22 to 4-24.
    \294\ 2018 PM2.5 Plan, Chapter 4, Table 4-8 and CARB
Resolution 18-49, 5.
    \295\ 2018 PM2.5 Plan, tables 4-4 and 4-5, and
SJVUAPCD Governing Board Resolution 18-11-16, 10-11.
---------------------------------------------------------------------------

    The anticipated implementation schedule for new CARB measures is
presented in Table 4-8 of the 2018 PM2.5 Plan and the
anticipated implementation schedule for new District measures is
presented both in Table H-2 of Appendix H and in Tables 4-4 and 4-5 of
the 2018 PM2.5 Plan. We summarize these schedules, as well
as the compliance schedules for those District measures that have been
adopted by December 2021, in Table IV-A (for CARB measures) and Table
IV-B (for District measures) of the EPA's 2012 Annual PM2.5
TSD. For example, implementation of Rule 4901 began November 1, 2019,
and implementation for Rules 4311, 4306, 4320, and 4702 will begin
December 31, 2023.
    Section H.1.3 of Appendix H of the Plan provides the State's and
District's justifications for the stepwise approach to meeting the RFP
requirement and the related implementation schedules for new or revised
control measures. These justifications include the time needed to
engage in the rulemaking process, including time for state and local
public processes; the need to provide time for industry to comply with
new regulatory requirements; the need to resolve feasibility issues for
emerging technologies; and, for CARB mobile source measures, the need
for affected industries to prepare technologies and infrastructure for
market-scale adoption.
    For example, Appendix H of the 2018 PM2.5 Plan states
that ``time after rule adoption will be necessary for unit
manufacturers and vendors to make available compliant equipment, and
for facility operators to source, purchase, and install new units or
compliant retrofit equipment. Dependent on the source category,
construction of controls will include engineering, site preparation and
infrastructure upgrades, unit installation, and operator training on
proper operation.'' \296\
---------------------------------------------------------------------------

    \296\ 2018 PM2.5 Plan, App. H, H-7.
---------------------------------------------------------------------------

    CARB and the District discussed in greater detail a number of
specific implementation challenges as part of their justification for
meeting the RFP requirement by the stepwise approach in the Plan. For
NOX, the new control measures that CARB and the District
anticipate implementing toward the end of the attainment period can be
found in tables 4-4, 4-5, and 4-8 of the 2018 PM2.5 Plan.
Appendix H of the 2018 PM2.5 Plan provides the following
explanation for the need to implement the listed measures in a stepwise
manner:
    ``The objective of many of CARB's new measures is to introduce or
advance innovative technologies in early stages of development or
market penetration. In the case of technology-forcing regulations, . .
. time is needed by the affected industry to ready the technologies,
including infrastructure, for market-scale adoption, and would have
been discussed previously by CARB and stakeholders during the measure
development phase. The time required to facilitate new and innovative
technologies is a principle driver of the timeline for control measure
implementation CARB laid out in Table 4-8.'' \297\
---------------------------------------------------------------------------

    \297\ 2018 PM2.5 Plan, App. H, H-8.
---------------------------------------------------------------------------

    CARB provided more specific information regarding two of these
measures on pages H-9 and H-10 of Appendix H. For instance, the
development of Heavy-Duty I/M was affirmed by California legislative
action in 2019, and CARB was working on program design and
infrastructure to implement new legislative direction.\298\ For the
California Low-NOX Engine Standard, the implementation
timeline has been influenced by a multi-year research program to assess
the feasibility of this standard. The development of these measures has
now culminated in adoption of Heavy-Duty I/M in December 2021 and the
California Low-NOX Engine Standard in August 2020, with
implementation beginning in 2023 and 2024, respectively.
---------------------------------------------------------------------------

    \298\ California Senate Bill 210, signed September 20, 2019.
---------------------------------------------------------------------------

    The new direct PM2.5 measures that CARB and the District
anticipate implementing toward the end of the attainment period can be
found in Tables 4-4, 4-5, and 4-8 of the 2018 PM2.5 Plan.
CARB's additional measures are expected to achieve 0.9 tpd of direct

PM2.5 emission reductions \299\ and the District's
additional measures are expected to achieve 1.3 tpd of direct
PM2.5 emission reductions by 2025.\300\ New or revised
District measures are thus expected to achieve a significant portion of
CARB and the District's 2.2 tpd direct PM2.5 emission
reduction commitment for the 2025 attainment year.
---------------------------------------------------------------------------

    \299\ 2018 PM2.5 Plan, Ch. 4, Table 4-9.
    \300\ Id. at Table 4-3. As discussed in section IV.F.3.d of this
proposed rule, pending final approval of the Agricultural Burning
Phase-out Measure, the District would have met its direct
PM2.5 emission reduction commitment of 1.3 tpd and, in
fact, exceeded it by 0.13 tpd.
---------------------------------------------------------------------------

    As discussed in section IV.F.3.c of this proposed rule, CARB and
the District have adopted 18 measures of the 27 control measure
commitments, a majority of which will achieve direct PM2.5
emission reductions in the SJV. In doing so, CARB and the District
concurrently developed and adopted measures for wide-ranging emission
sources such as heavy-duty trucks, agricultural equipment, local
trucks, small off-road engines, flares, boilers, stationary internal
combustion engines, and residential wood burning.
    With respect to the commercial charbroiling, according to
information provided in Appendix C of the 2018 PM2.5 Plan,
the costs associated with retrofitting control technology onto
equipment at existing restaurants and maintaining such equipment can be
prohibitively expensive, especially for smaller restaurants.\301\
Because of ongoing uncertainties about the technological and economic
feasibility of controls for under-fired charbroiling (UFC), the
District adopted a set of registration and reporting provisions in a
revised version of Rule 4692 that required owners and operators of
commercial cooking operations with UFCs to register each unit and to
submit, by January 1, 2019, a one-time informational report providing
information about the UFC and its operations. CARB submitted this
revised rule to the EPA on November 16, 2018, and the EPA approved the
rule amendments into the California SIP on September 14, 2020.\302\
---------------------------------------------------------------------------

    \301\ 2018 PM2.5 Plan, App. C, C-209 to C-210.
    \302\ 85 FR 56521.
---------------------------------------------------------------------------

    While the District has not proposed to its Governing Board
amendments to Rule 4692 that impose new control requirements on UFCs,
in presenting the District's ``Commercial Underfired Charbroiling
Emission Reduction Strategy'' to its Governing Board on December 17,
2020, the District expressed continued difficulty in identifying
feasible control technologies for under-fired charbroiling restaurants,
particularly given the ``unprecedented impacts of the COVID-19 pandemic
to the restaurant industry'' that limited revenue streams.\303\
Nevertheless, the District continues to work on this source category,
including the evaluation of ``potential amendments to Rule 4692 in the
near future.'' \304\
---------------------------------------------------------------------------

    \303\ SJVUAPCD, ``Item Number 11: Adopt Proposed Commercial
Under-fired Charbroiling Emission Reduction Strategy,'' December 17,
2020, 2.
    \304\ 2021 Progress Report, 9.
---------------------------------------------------------------------------

    The 2018 PM2.5 Plan also shows that a portion of the
necessary direct PM2.5 emission reductions in 2025 (0.32 of
2.2 tpd) is expected to result from a revised version of the District's
Conservation Management Practices (CMP) rule (Rule 4550), which is
designed to reduce particulate emissions from agricultural
operations.\305\ The District hosted a public scoping meeting on
potential amendments to Rule 4550 on December 16, 2021,\306\ and
anticipates proposing this revised rule to the SJVUAPCD Governing Board
in 2022 and implementing it beginning in 2024.\307\ As explained in
Appendix C of the 2018 PM2.5 Plan, an important step in
developing effective PM2.5 controls for dust from
agricultural operations is to develop an understanding of the
effectiveness of CMPs on controlling PM2.5 emissions in the
Valley.\308\ Towards this end, the District intends to work with
stakeholders and researchers to evaluate the feasibility and
effectiveness of additional control measures to reduce PM2.5
emissions, including: Tilling and other land preparation activities;
selection of conservation tillage as a CMP for croplands; and CMPs on
fallow lands that are tilled or otherwise worked with implements of
husbandry (e.g., a farm tractor drawing a trailer with crops) to reduce
windblown PM emissions from disturbed fallowed acreage.\309\
---------------------------------------------------------------------------

    \305\ 2018 PM2.5 Plan, Ch. 4, Table 4-3.
    \306\ SJVUAPCD, ``Notice of Public Scoping Meeting, Rule 4550
(Conservation Management Practices),'' December 2, 2021. The
District also held a series of workshops from January to March 2020
with the stated goal of ``assisting growers and dairy families in
understanding and complying with District Rule 4550.'' SJVUAPCD,
``Air Quality Workshop Series Focused on Conservation Management
Practices (CMP) Plans,'' available at https://www.valleyair.org/Workshops/postings/2020/2020_CMP/notice.pdf.
    \307\ 2018 PM2.5 Plan, Ch. 4, Table 4-4.
    \308\ 2018 PM2.5 Plan, App. C, C-203.
    \309\ Id. at C-203.
---------------------------------------------------------------------------

(b) Quantitative Milestones
    Appendix H of the 2018 PM2.5 Plan identifies October 15
milestone dates for the 2019 and 2022 RFP milestone years, the 2025
attainment year, and a post-attainment milestone year of 2028.\310\
Appendix H also identifies target emissions levels to meet the RFP
requirement for direct PM2.5 and NOX emissions
for each of these milestone years,\311\ as shown in Table 6 of this
proposed rule, and control measures that CARB and the District plan to
implement by each of these years, in accordance with the control
strategy in the Plan.\312\
---------------------------------------------------------------------------

    \310\ 2018 PM2.5 Plan, App. H, Table H-12.
    \311\ Id. at Table H-5.
    \312\ Id. at H-23 to H-24 (for CARB milestones) and H-20 to H-22
(for District milestones).
---------------------------------------------------------------------------

    We note, however, that while quantitative milestones are required
for 2019 in the context of the Moderate area plan for the 2012 annual
PM2.5 NAAQS in the SJV (corresponding to the 4.5 years after
the date of designation), we have already evaluated and approved the
State's quantitative milestones for 2019, as supplemented by the 2018
PM2.5 Plan.\313\ Therefore, the EPA is not evaluating the
2019 milestones for purposes of the State's Serious area plan for the
2012 annual PM2.5 NAAQS in the SJV. Similarly, given that
the 2018 PM2.5 Plan includes a demonstration of attainment
by the 10th calendar year following designations, quantitative
milestones are not required beyond 10.5 years after the date of
designation (i.e., October 15, 2025). Therefore, the EPA is not
evaluating the 2028 milestones for purposes of the submitted Serious
area plan.
---------------------------------------------------------------------------

    \313\ 86 FR 67343, 67346.
---------------------------------------------------------------------------

    The 2018 PM2.5 Plan estimates that emissions of direct
PM2.5 and NOX will generally decline from the
2013 base year to the 2025 attainment year and that direct
PM2.5 and NOX are emitted by a large number and
range of sources in the SJV. With respect to emission reductions, the
2018 PM2.5 Plan relies on the baseline measures reflected in
the Plan's emissions inventory to demonstrate RFP through 2022.\314\
---------------------------------------------------------------------------

    \314\ 2018 PM2.5 Plan, App. H, H-4 to H-15.
---------------------------------------------------------------------------

    In addition to these baseline measures, the 2018 PM2.5
Plan's control strategy includes specific control measure commitments
for purposes of attaining the 2012 annual PM2.5 NAAQS by
2025, including commitments by CARB and the District to develop and
propose to their respective boards specific regulatory and incentive-
based measures identified in the plan by specific years leading up to
2025, including 2019 and 2022.\315\ Although

the attainment demonstration does not rely on these control measure
commitments for emission reductions until 2025,\316\ the RFP and
quantitative milestone elements of the 2018 PM2.5 Plan rely
on these control measure commitments to demonstrate that the plan
requires RFP toward attainment.\317\
---------------------------------------------------------------------------

    \315\ CARB Resolution 18-49, 5; 2018 PM2.5 Plan, Ch.
4, Table 4-8; email dated November 12, 2019, from Sylvia Vanderspek,
CARB to Anita Lee, EPA Region IX, ``RE: SJV PM2.5
information'' (attaching ``Valley State SIP Strategy Progress'');
CARB 2018 Staff Report, 14; SJVUAPCD Governing Board Resolution 18-
11-16, 10-11; 2018 PM2.5 Plan, Ch. 4, tables 4-4 and 4-5;
and email dated November 12, 2019, from Jon Klassen, SJVUAPCD to
Wienke Tax, EPA Region IX, ``RE: follow up on aggregate commitments
in SJV PM2.5 plan'' (attaching ``District Progress in
Implementing Commitments with 2018 PM2.5 Plan'').
    \316\ 2018 PM2.5 Plan, Ch. 4, Table 4-3 (``Emission
Reductions from District Measures'') and Table 4-9 (``San Joaquin
Valley Expected Emission Reductions from State Measures'').
    \317\ 2018 PM2.5 Plan, App. H, H-4 to H-10
(describing commitments by CARB and SJVUAPCD to adopt additional
measures to fulfill tonnage commitments for 2024 and 2025, including
``action'' and ``implementation'' dates occuring before 2024 to
ensure expeditious progress toward attainment).
---------------------------------------------------------------------------

    For the 2022 milestone year, Appendix H of the 2018
PM2.5 Plan describes the District's quantitative milestone
as a report on ``[t]he status of SIP measures adopted between 2019 and
2022 as per the schedule included in the adopted Plan, including
Residential Wood Burning Strategy and Commercial Under-Fired
Charbroiler incentive-based strategy.'' \318\ The schedule for
development of new or revised SIP measures in the 2018 PM2.5
Plan identifies ``action dates'' between 2019 and 2022 for 12 District
measures listed in tables 4-4 and 4-5 of Chapter 4, including, for
example, Rule 4311 (``Flares''), Rule 4702 (``Internal Combustion
Engines'') and Rule 4354 (``Glass Melting Furnaces'').\319\
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    \318\ 2018 PM2.5 Plan, App. H, H-20.
    \319\ 2018 PM2.5 Plan, Ch. 4, 4-12 and 4-13 (tables
4-4 and 4-5). See also email dated November 12, 2019, from Jon
Klassen, SJVUAPCD to Wienke Tax, EPA Region IX, ``RE: follow up on
aggregate commitments in SJV PM2.5 plan'' (attaching
``District Progress in Implementing Commitments with 2018
PM2.5 Plan,'' stating the District's intent to take
action on the listed rules and measures by beginning the public
process on each measure and then proposing the rule or measure to
the SJVUAPCD Governing Board).
---------------------------------------------------------------------------

    Appendix H describes CARB's quantitative milestone as a report on
two measure-specific milestones: (1) Actions taken between 2019 and
2022 to implement the Truck and Bus Regulation that required
particulate filters and cleaner engine standards on existing heavy-duty
diesel trucks and buses in California, and (2) the ``status of SIP
measures adopted between 2019 and 2022, including Advanced Clean Cars 2
and the Heavy-Duty Vehicle Inspection and Maintenance Program.'' \320\
The schedule for development of new or revised CARB measures in the
2018 PM2.5 Plan identifies ``action'' dates between 2019 and
2022 for 13 CARB measures listed in Table 4-8 of Chapter 4, including,
for example, Heavy-Duty I/M, the SORE regulation, and the Low-Emission
Diesel Fuel Requirement.\321\
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    \320\ 2018 PM2.5 Plan, App. H, H-23.
    \321\ 2018 PM2.5 Plan, Ch. 4, 4-28 (Table 4-8). See
also email dated November 12, 2019, from Sylvia Vanderspek, CARB to
Anita Lee, EPA Region IX, ``RE: SJV PM2.5 information''
(attaching ``Valley State SIP Strategy Progress'') and CARB 2018
Staff Report, 14-15 (stating CARB's intent to ``bring to the Board
or take action on the list of proposed State measures for the
Valley'' by the action dates specified in Table 2).
---------------------------------------------------------------------------

    For the 2025 attainment year, Appendix H of the 2018
PM2.5 Plan describes the District's quantitative milestone
as a report on ``[i]mplementation of amendments to Residential Wood
Burning Strategy, including any regulatory amendments and enhancements
to the District Burn Cleaner incentive program,'' ``[i]mplementation of
amendments to the Commercial Under-Fired [Charbroiler] Strategy,
including any regulatory amendments and implementation of related
incentive-based strategy,'' and ``[t]he status of SIP measures adopted
between 2022 and 2025 as per the schedule included in the adopted
Plan.'' \322\ The schedule for development of new or revised SIP
control measures in the 2018 PM2.5 Plan identifies ``action
dates'' between 2022 and 2025 for one District measure: Rule 4550
(``Conservation Management Practices'').\323\
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    \322\ 2018 PM2.5 Plan, App. H, H-20 to H-21.
    \323\ 2018 PM2.5 Plan, Ch. 4, 4-12 (Table 4-4). See
also email dated November 12, 2019, from Jon Klassen, SJVUAPCD to
Wienke Tax, EPA Region IX, ``RE: follow up on aggregate commitments
in SJV PM2.5 plan'' (attaching ``District Progress in
Implementing Commitments with 2018 PM2.5 Plan,'' stating
the District's intent to take action on the listed rules and
measures by beginning the public process on each measure and then
proposing the rule or measure to the SJVUAPCD Governing Board).
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    Appendix H describes CARB's quantitative milestone as a report on
three measure-specific milestones: (1) ``[i]dentify the number of
pieces of agricultural equipment turned over to Tier 4 Final due to the
Accelerated Turnover of Agricultural Tractors Measure through 2025;''
(2) ``[i]dentify the number of trucks and buses turned over to a low-
NOX engine or cleaner due to the Accelerated Turnover of
Trucks and Buses Measure through 2025;'' and (3) ``[t]he status of SIP
measures adopted between 2022 and 2025, including the proposed Cleaner
In-Use Agricultural Equipment Measure to incentivize the penetration of
cleaner agricultural equipment used in California.'' \324\ The schedule
for development of new or revised CARB measures in the 2018
PM2.5 Plan identifies ``action'' dates between 2022 and 2025
for one CARB measure: The Cleaner In-Use Agricultural Equipment
measure.\325\
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    \324\ 2018 PM2.5 Plan, App. H, H-23.
    \325\ 2018 PM2.5 Plan, Ch. 4, 4-28 (Table 4-8). See
also email dated November 12, 2019, from Sylvia Vanderspek, CARB to
Anita Lee, EPA Region IX, ``RE: SJV PM2.5 information''
(attaching ``Valley State SIP Strategy Progress'') and CARB 2018
Staff Report, 14-15 (stating CARB's intent to ``bring to the Board
or take action on the list of proposed State measures for the
Valley'' by the action dates specified in Table 2).
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3. EPA Evaluation and Proposed Action
(a) Reasonable Further Progress
    We have evaluated the RFP demonstration in Appendix H of the 2018
PM2.5 Plan and, for the following reasons, propose to find
that it satisfies the statutory and regulatory requirements for RFP.
First, the Plan contains an anticipated implementation schedule for the
attainment control strategy, including all BACM and BACT control
measures and CARB and the District's aggregate tonnage commitments, as
required by 40 CFR 51.1012(a)(1). The implementation schedule is found
in Tables 4-4, 4-5, and 4-8 of the 2018 PM2.5 Plan and in
Table H-2 of Appendix H. The 2018 PM2.5 Plan documents the
State's and District's conclusion that they are implementing all BACM
and BACT for direct PM2.5 and NOX emissions in
the Valley as expeditiously as practicable.\326\
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    \326\ The BACM/BACT control strategy that provides the basis for
these emissions projections is described in Chapter 4, App. C, and
App. D of the 2018 PM2.5 Plan.
---------------------------------------------------------------------------

    Second, the RFP demonstration contains projected emission levels
for direct PM2.5 and NOX for each applicable
milestone year as required by 40 CFR 51.1012(a)(2). These projections
are based on continued implementation of the existing control measures
in the area (i.e., baseline measures) and commitments to achieve
additional reductions from new measures by 2025, and reflect full
implementation of the State's, District's, and MPOs' attainment control
strategy for these pollutants.
    Third, the projected emissions levels based on the implementation
schedule in the Plan demonstrate that the control strategy will achieve
reasonable further progress toward attainment between the 2013 baseline
year and the 2025 attainment year as required by 40 CFR 51.1012(a)(3).
Tables 7 and 8 of this proposed rule show decreases in emissions levels
in each milestone year, leading to the achievement of the reductions
required for attainment in 2025.

    Finally, the RFP demonstration shows that overall pollutant
emissions will be at levels that reflect stepwise progress between the
base year and the attainment year and provides a justification for the
selected implementation schedule, as required by 40 CFR 51.1012(a)(4).
The steeper decline in emissions by 2025 is primarily due to
commitments by CARB and the District to achieve reductions from new
control measures by 2025. CARB and the District's justifications for
their selected implementation schedules, i.e., for the delay in their
respective commitments to achieve emissions reductions from new or
revised control measures, include the time needed for rulemaking
processes, the time needed for industry to comply with new regulatory
requirements, the need to resolve feasibility issues for emerging
technologies, and the time needed to prepare technologies and
infrastructure for market-scale adoption.
    We note that although both CARB and the District have committed to
propose to their respective boards certain new or revised control
measures in the years leading up to the 2025 attainment year, the only
enforceable commitment in the Plan that requires adoption of control
measures is the tonnage commitment for reductions by 2025, which
provides the basis for the stepwise approach to RFP.
(b) Quantitative Milestones
    Appendix H of the 2018 PM2.5 Plan identifies milestone
dates for the Serious plan (i.e., October 15, 2022, and October 15,
2025) that are consistent with the requirements of 40 CFR
51.1013(a)(2)(i) and target emissions levels for direct
PM2.5 and NOX to be achieved by these milestone
dates through implementation of the Plan's control strategy. These
target emission levels and associated control requirements provide for
objective evaluation of the area's progress towards attainment of the
2012 annual PM2.5 NAAQS.
    CARB's quantitative milestones in Appendix H are to take action on
or to implement specific measures listed in the State's control measure
commitments that apply to heavy-duty trucks and buses, light-duty
vehicles, and non-road equipment sources and may provide substantial
reductions in emissions of direct PM2.5 and NOX
from mobile sources in the SJV. Similarly, the District's quantitative
milestones in Appendix H are to take action on or to implement specific
measures listed in the District's control measure commitments that
apply to sources such as residential wood burning, conservation
management practices, glass melting furnaces, and internal combustion
engines and that may provide substantial reductions in emission of
direct PM2.5 and NOX from stationary sources.
These milestones provide an objective means for tracking CARB and the
District's progress in implementing their respective control measure
and aggregate tonnage commitments and, thus, provide for objective
evaluation of the SJV's progress toward timely attainment.
    For these reasons, we propose to determine that the SJV
PM2.5 Plan satisfies the requirements for quantitative
milestones in CAA section 189(c) and 40 CFR 51.1013 for the 2012 annual
PM2.5 NAAQS in the SJV.
    We note that on January 13, 2020, CARB submitted the ``2019
Quantitative Milestone Report for the 2012 PM2.5 NAAQS
(``SJV 2019 QM Report'') for the Moderate area plan to the EPA,\327\
which the EPA is currently reviewing.
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    \327\ Letter dated January 13, 2020, from Richard W. Corey,
Executive Officer, CARB, to Mike Stoker, Regional Administrator, EPA
Region IX, with enclosures.
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H. Contingency Measures

1. Requirements for Contingency Measures
    Under CAA section 172(c)(9), states required to make an attainment
plan SIP submission must include contingency measures that they will
implement if the area fails to meet RFP (``RFP contingency measures'')
or fails to attain the NAAQS by the applicable attainment date
(``attainment contingency measures''). Under the PM2.5 SIP
Requirements Rule, states must include contingency measures that will
be implemented following a determination by the EPA that the state has
failed: (1) To meet any RFP requirement in the approved attainment
plan; (2) to meet any quantitative milestone in the approved attainment
plan; (3) to submit a required quantitative milestone report; or (4) to
attain the applicable PM2.5 NAAQS by the applicable
attainment date.\328\ Contingency measures must be fully adopted rules
or control measures that are ready to be implemented quickly and
without significant further action by the state or the EPA upon failure
to meet RFP or failure of the area to meet the relevant NAAQS by the
applicable attainment date.\329\
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    \328\ 40 CFR 51.1014(a).
    \329\ 81 FR 58010, 58066 and General Preamble Addendum, 42015.
---------------------------------------------------------------------------

    The purpose of contingency measures is to continue progress in
reducing emissions while a state revises its SIP to meet the missed RFP
requirement or to correct ongoing nonattainment. Neither the CAA nor
the EPA's implementing regulations establish a specific amount of
emission reductions that implementation of contingency measures must
achieve, but the EPA recommends that contingency measures should
provide for emission reductions equivalent to approximately one year of
reductions needed for RFP in the nonattainment area, calculated as the
overall level of reductions needed to demonstrate attainment divided by
the number of years from the base year to the attainment year. In
general, we expect all actions needed to effect full implementation of
the measures to occur within 60 days after the EPA notifies the state
of a failure to meet RFP or to attain.\330\
---------------------------------------------------------------------------

    \330\ 81 FR 58010, 58066. See also General Preamble 13512,
13543-13544, and General Preamble Addendum, 42014-42015.
---------------------------------------------------------------------------

    To satisfy the requirements of 40 CFR 51.1014, the contingency
measures adopted as part of a PM2.5 attainment plan must
consist of control measures for the area that are not otherwise
required to meet other attainment plan requirements (e.g., to meet
RACM/RACT requirements) and must specify the timeframe within which
their requirements become effective following any of the EPA
determinations specified in 40 CFR 51.1014(a). To meet CAA section
172(c)(9), contingency measures must be measures that are triggered and
implemented only after the EPA determines that an area fails to meet
RFP requirements or to attain by the applicable attainment date, and
the state must not have begun to implement such measures before this
determination is made. Thus, already-implemented measures cannot serve
as contingency measures under CAA section 172(c)(9).\331\
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    \331\ See Bahr v. EPA, 836 F.3d 1218, 1235 (9th Cir. 2016),
Sierra Club v. EPA, 985 F.3d 1055 (DC Cir. 2021), and Assoc. of
Irritated Residents v. EPA, 10 F.4th 937 (9th Cir. 2021).
---------------------------------------------------------------------------

2. Summary of State's Submission
    The 2018 PM2.5 Plan addresses the contingency measure
requirement for the 2012 annual PM2.5 NAAQS by reference to
the contingency measure portion of a separate December 2018 SIP
submission that involved enhanced enforcement of CARB regulations in
the SJV, a commitment to amend the District's residential wood burning
rule (i.e., District Rule 4901) to include contingent provisions, and
emissions estimates for the year following the attainment year for use
in evaluating whether the emissions reductions from the contingency
measures are

sufficient.\332\ In January 2021, CARB withdrew the enhanced
enforcement portion of the December 2018 SIP submission as it pertained
to the 2012 annual PM2.5 NAAQS in the SJV.\333\
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    \332\ 2018 PM2.5 Plan, App. H (revised February 11,
2020), H-24 to H-26.
    \333\ Letter dated January 8, 2021, from Richard W. Corey,
Executive Officer, CARB, to John W. Busterud, Regional
Administrator, EPA Region IX, with enclosures.
---------------------------------------------------------------------------

    With respect to the District contingency measure, the 2018
PM2.5 Plan states that the District will amend District Rule
4901 to include a requirement that would be triggered should the EPA
issue a final rulemaking that the SJV failed to meet a regulatory
requirement necessitating implementation of a contingency measure.\334\
The District adopted amendments to Rule 4901 on June 20, 2019,
including a contingency measure in section 5.7.3 of the amended rule,
and CARB submitted the amended rule to the EPA for approval on July 22,
2019.\335\ In this proposal, we are evaluating District Rule 4901,
specifically, section 5.7.3, for compliance with the requirements for
contingency measures for purposes of meeting the Serious area planning
requirements for the 2012 annual PM2.5 NAAQS.
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    \334\ 2018 PM2.5 Plan, App. H, H-25.
    \335\ SJVUAPCD Rule 4901, as amended on June 20, 2019, was
submitted electronically to the EPA on July 22, 2019, as an
attachment to a letter dated July 19, 2019, from Richard W. Corey,
Executive Officer, CARB, to Mike Stoker, Regional Administrator, EPA
Region IX.
---------------------------------------------------------------------------

    District Rule 4901 is designed to limit emissions generated by the
use of wood burning fireplaces, wood burning heaters, and outdoor wood
burning devices. The rule establishes requirements for the sale/
transfer, operation, and installation of wood burning devices and for
advertising the sale of seasoned wood consistent with a moisture
content limit within the SJV.
    The rule includes a two-tiered, episodic wood burning curtailment
requirement that applies during four winter months, November through
February. During a level one episodic wood burning curtailment, section
5.7.1 prohibits any person from operating a wood burning fireplace or
unregistered wood burning heater but permits the use of a properly
operated wood burning heater that meets certification requirements and
has a current registration with the District. Sections 5.9 through 5.11
impose specific registration requirements on any person operating a
wood burning fireplace or wood burning heater and section 5.12 imposes
specific certification requirements on wood burning heater
professionals. During a level two episodic wood burning curtailment,
operation of any wood burning device is prohibited by section 5.7.2.
    Prior to the 2019-2020 wood burning season, the District imposed a
level one curtailment when the PM2.5 concentration was
forecasted to be between 20-65 [mu]g/m\3\ and imposed a level two
curtailment when the PM2.5 concentration was forecasted to
be above 65 [mu]g/m\3\ or the PM10 concentration was
forecasted to be above 135 [mu]g/m\3\. In 2019, the District adopted
revisions to Rule 4901 to lower the wood burning curtailment thresholds
in the ``hot spot'' counties of Madera, Fresno, and Kern. The District
lowered the level one PM2.5 threshold for these three
counties from 20 [mu]g/m\3\ to 12 [mu]g/m\3\, and the level two
PM2.5 threshold from 65 [mu]g/m\3\ to 35 [mu]g/m\3\. The
District did not modify the curtailment thresholds for other counties
in the SJV--those levels remained at 20 [mu]g/m\3\ for level one and 65
[mu]g/m\3\ for level two.
    The District's 2019 revision to Rule 4901 also included the
addition of a contingency measure in section 5.7.3 of the rule,
requiring that 60 days following the effective date of an EPA final
rulemaking that the SJV has failed to attain the 1997, 2006, or 2012
PM2.5 NAAQS by the applicable attainment date, the
PM2.5 curtailment levels for any county that has failed to
attain the applicable standard will be lowered to the curtailment
levels in place for hot spot counties. The District estimates that the
potential emissions reduction in direct PM2.5 would be in
the range of 0.014 tpd (if the contingency is triggered in Kings County
but not the other non-hot-spot counties) to 0.387 tpd (if the
contingency is triggered in all five of the non-hot-spot counties), but
there would be no emissions reduction if, at the time of the
determination of failure to attain the 2012 annual PM2.5
NAAQS by the attainment date, violations of the 2012 annual
PM2.5 NAAQS occurred only at monitors in the hot-spot
counties.\336\ The corresponding potential NOX emissions
reduction would be in the range of 0.002 tpd to 0.060 tpd,
respectively, but as previously noted there would be no emissions
reduction if the monitored violations occur in the hot-spot counties
only.\337\
---------------------------------------------------------------------------

    \336\ See Table B-13 in Appendix B from the District's Final
Staff Report (June 20, 2019) for revisions to Rule 4901.
    \337\ NOX emissions reductions from the contingency
measure are based on the District's estimates for direct
PM2.5 emissions using the ratio of direct
PM2.5 to NOX in Table 1 of the District's
Final Staff Report (June 20, 2019) for revisions to Rule 4901.
---------------------------------------------------------------------------

3. EPA Evaluation and Proposed Action
    We have evaluated the contingency measure element of the 2018
PM2.5 Plan and associated contingency measure in District
Rule 4901 (i.e., section 5.7.3 of the rule) against the requirements of
CAA section 172(c)(9) and 40 CFR 51.1014 for both attainment and RFP
contingency measures, and the related requirements for submission of
quantitative milestone reports and compliance with quantitative
milestones. We propose to find that the contingency measure element of
the 2018 PM2.5 Plan (and contingency measure in District
Rule 4901) is inadequate to meet the Serious area contingency measure
requirements for the 2012 annual PM2.5 NAAQS for several
reasons.
    As noted in our summary of the State's submission, the contingency
measure in District Rule 4901 is structured to provide for
implementation if the area fails to attain the 2012 annual
PM2.5 NAAQS, not before, and is therefore consistent with
the requirement under CAA section 172(c)(9) that contingency measures
be prospective and conditional, rather than already being implemented.
However, as structured, the contingency measure of Rule 4901 (i.e.,
section 5.7.3) would provide for emissions reductions only in Kings,
Merced, San Joaquin, Stanislaus, and/or Tulare counties, not the ``hot
spot'' counties of Fresno, Kern, and Madera, and only if a violating
monitoring site (i.e., a site where the collected data represent a
violation of the NAAQS) is located in such county. In other words, if
the EPA's determination of failure to attain the NAAQS by the
applicable attainment date indicates violations at monitoring sites in
Fresno and Kern (``hot spot'' counties) and Tulare (non-hot-spot
county) counties, the contingency measure would provide for emissions
reductions by lowering the wood burning curtailment thresholds in
Tulare County only. The ``hot spot'' counties are already subject to
the lower wood burning curtailment thresholds in the rule and thus
would not be affected by the finding of failure to attain determination
and the other non-``hot spot'' counties (i.e., other than Tulare County
in this example) would not be subject to the lower wood burning
curtailment thresholds.
    In accordance with 40 CFR 51.1014, the contingency measure in
District Rule 4901 identifies a specific triggering mechanism. In this
case, the triggering mechanism in the rule is the EPA's final
determination that the SJV has failed to attain the 2012 annual
PM2.5 NAAQS by

the applicable attainment date.\338\ The rule also specifies a
timeframe within which its requirements become effective after a
failure-to-attain determination (i.e., on and after 60 days from the
effective date of the EPA's final determination), and would take effect
with minimal further action by the state or the EPA. However, the
contingency measure in District Rule 4901 does not address the
potential for State failures to meet a quantitative milestone, submit a
quantitative milestone report, or failure to meet an RFP
requirement.\339\
---------------------------------------------------------------------------

    \338\ Section 5.7.3 of Rule 4901 states that ``the District
shall notify the public of an Episodic Curtailment for the
PM2.5 curtailment levels described in Sections <IP_ADDRESS>
and <IP_ADDRESS> for any county that has failed to attain the applicable
standard.'' (emphasis added) We interpret this to mean that the
District would apply the more stringent curtailment provisions for
any county identified in the EPA's final rule making the
determination that the SJV failed to attain the applicable
PM2.5 NAAQS.
    \339\ We note that section 5.7.3 of District Rule 4901 applies
the lower thresholds ``on and after sixty days following the
effective date of EPA final rulemaking,'' which is appropriate as a
contingency measure trigger for a failure to attain by the
applicable attainment date given that the EPA conducts rulemaking to
make such determinations. However, for the three other contingency
triggers, i.e., State failures to meet a quantitative milestone,
submit a quantitative milestone report, or failure to meet an RFP
requirement, the EPA may not conduct rulemaking but instead make the
determinations through correspondence directly to the State. Thus,
we recommend that section 5.7.3 of District Rule 4901 be amended to
refer to ``EPA final determinations'' rather than to ``EPA final
rulemaking'' if the rule is amended to include the additional
contingency measure triggers.
---------------------------------------------------------------------------

    In addition, the contingency measure provision of Rule 4901 is not
structured to achieve any additional emissions reductions if the EPA
finds that monitoring locations in the ``hot spot'' counties (i.e.,
Fresno, Kern, or Madera Counties) are the only ones in the SJV that are
violating the 2012 annual PM2.5 NAAQS as of the attainment
date. To qualify as a contingency measure, a measure must be structured
to achieve emissions reductions if triggered, and the contingency
measure of District Rule 4901 provides for such reductions only under
certain circumstances. If the District intends to retain a contingency
provision in Rule 4901, the District should revise the rule to provide
for additional emissions reductions in the SJV (if triggered)
regardless of which monitoring site(s) is determined to be violating
the 2012 annual PM2.5 NAAQS as of the attainment date.\340\
---------------------------------------------------------------------------

    \340\ The EPA believes that the most straightforward remedy
under these circumstances would be for the District to amend section
5.7.3 of Rule 4901 to extend the lower wood burning curtailment
thresholds region-wide if the EPA determines that the area has
failed to attain the 2012 annual PM2.5 NAAQS by the
applicable attainment date.
---------------------------------------------------------------------------

    Next, we considered the adequacy of the contingency measure in
section 5.7.3 of District Rule 4901 from the standpoint of the
magnitude of emissions reductions the measure would provide if
triggered. Neither the CAA nor the EPA's implementing regulations for
the PM2.5 NAAQS establish a specific amount of emissions
reductions that implementation of contingency measures must achieve,
but the EPA has long recommended that contingency measures should
provide for emissions reductions approximately equivalent to one year's
worth of RFP, which in the case of the Serious area attainment plan
amounts to reductions of approximately 0.5 tpd of direct
PM2.5 and 17.3 tpd of NOX for the 2012 annual
PM2.5 NAAQS in the SJV.\341\ As noted in our summary of the
State's submission, the emissions reductions from the contingency
measure in District Rule 4901 would amount to approximately 0.00 tpd to
0.387 tpd of direct PM2.5, which equates to approximately 0%
to 77% of one year's worth of RFP for direct PM2.5. With
respect to NOX emissions reductions, the contingency measure
in District Rule 4901 would amount to approximately 0.00 tpd to 0.06
tpd, which equates to approximately 0% to 0.3% of one year's worth of
RFP for NOX. As such, the emissions reductions from the
contingency measure in section 5.7.3 of Rule 4901, if triggered, would
be far less than one year's worth of progress with respect to the 2012
annual PM2.5 NAAQS in the SJV. District Rule 4901 alone, and
as currently formulated, would provide insufficient emission reductions
to meet the contingency measures requirement.
---------------------------------------------------------------------------

    \341\ The calculation of one year's worth of RFP is based on
dividing the values in column E of table H-6 of Appendix H (updated
February 11, 2020) of the 2018 PM2.5 Plan by 12, i.e.,
the number of years between 2013 and 2025. We consider that the fact
that this element focuses only on direct PM2.5 and
NOX (and not ammonia, SO2, and VOC) is
acceptable in light of our proposed approval of the precursor
demonstration in section IV.B of this proposed rule.
---------------------------------------------------------------------------

    For these reasons, we propose to disapprove the contingency measure
element of the 2018 PM2.5 Plan (and the related contingency
measure in District Rule 4901) under CAA section 179(c)(9) and 40 CFR
51.1014 with respect to the Serious area planning requirements for the
2012 annual PM2.5 NAAQS in the SJV. While the contingency
measure provision of the 2019 amendment to Rule 4901 has an adequate
triggering mechanism for failure to attain, we propose to disapprove it
because it may result in no emissions reductions if the area fails to
attain the NAAQS by the applicable attainment date. Furthermore,
because the contingency measure element and the contingency measure of
Rule 4901 lack any to-be-triggered measure for failure to meet a
quantitative milestone, failure to submit a quantitative milestone
report, or failure to meet an RFP requirement, we propose that the
submissions are also inadequate with respect to the RFP contingency
measure requirements. Lastly, the contingency measure element, and the
associated contingency measure in District Rule 4901, fail to provide
emissions reductions roughly equivalent to one year's worth of progress
or to provide an adequate reasoned justification why a smaller amount
of emissions reductions is appropriate.\342\
---------------------------------------------------------------------------

    \342\ 81 FR 58010, 58067. We note that the 2018 PM2.5
Plan includes estimates of surplus emissions reductions from
already-implemented measures to support approval of the contingency
measure; however, a recent Ninth Circuit decision rejected reliance
on surplus emissions reductions from already-implemented measures as
the basis for approving a contingency measure element that relied on
a contingency measure that would provide far less than one year's
worth of progress. See Assoc. of Irritated Residents v. EPA, 10
F.4th 937 (9th Cir. 2021).
---------------------------------------------------------------------------

    If the EPA finalizes the proposed disapproval of the contingency
measure element for the 2012 annual PM2.5 NAAQS and
finalizes approval of the Plan's RFP demonstration, modeled attainment
demonstration, and motor vehicle emissions budgets, the area would be
eligible for a protective finding under the transportation conformity
rule because the 2018 PM2.5 Plan reflects adopted control
measures and contains enforceable commitments that fully satisfy the
emissions reductions requirements for RFP and attainment for the 2012
annual PM2.5 NAAQS.\343\
---------------------------------------------------------------------------

    \343\ 40 CFR 93.120(a)(3).
---------------------------------------------------------------------------

I. Motor Vehicle Emission Budgets

1. Requirements for Motor Vehicle Emission Budgets
    Section 176(c) of the CAA requires federally funded or approved
actions in nonattainment and maintenance areas to conform to the SIP's
goals of eliminating or reducing the severity and number of violations
of the NAAQS and achieving expeditious attainment of the standards.
Conformity to the SIP's goals means that such actions will not: (1)
Cause or contribute to new violations of a NAAQS, (2) increase the
frequency or severity of an existing violation, or (3) delay timely
attainment of any NAAQS or any interim milestone.
    Actions involving Federal Highway Administration (FHWA) or Federal
Transit Administration (FTA) funding

or approval are subject to the EPA's transportation conformity rule,
codified at 40 CFR part 93, subpart A (``Transportation Conformity
Rule''). Under this rule, metropolitan planning organizations (MPOs) in
nonattainment and maintenance areas coordinate with state and local air
quality and transportation agencies, the EPA, FHWA, and FTA to
demonstrate that an area's regional transportation plans (RTP) and
transportation improvement programs (TIP) conform to the applicable
SIP. This demonstration is typically done by showing that estimated
emissions from existing and planned highway and transit systems are
less than or equal to the motor vehicle emissions budgets (``budgets'')
contained in all control strategy plans applicable to the area. An
attainment or maintenance plan for the PM2.5 NAAQS should
include budgets for the attainment year, each required RFP milestone
year, or the last year of the maintenance plan, as appropriate, for
direct PM2.5 and PM2.5 precursors subject to
transportation conformity analyses. Budgets are generally established
for specific years and specific pollutants or precursors and must
reflect all of the motor vehicle control measures contained in the
attainment and RFP demonstrations.\344\
---------------------------------------------------------------------------

    \344\ 40 CFR 93.118(e)(4)(v).
---------------------------------------------------------------------------

    Under the PM2.5 SIP Requirements Rule, Serious area
PM2.5 attainment plans must include appropriate quantitative
milestones and projected RFP emissions levels for direct
PM2.5 and all PM2.5 plan precursors in each
milestone year.\345\ For an area designated nonattainment for the 2012
annual PM2.5 NAAQS, a Serious area attainment plan that
demonstrates attainment by the end of the 10th calendar year following
the date of designation must contain quantitative milestones to be
achieved no later than 7.5 years and 10.5 years after the date the area
was designated nonattainment.\346\ Given that the SJV was designated
nonattainment for the 2012 annual PM2.5 NAAQS effective
April 15, 2015, the required Serious area milestone dates for the SJV
are October 15, 2022, and October 15, 2025. Given that the 2018
PM2.5 Plan includes a demonstration of attainment of these
NAAQS by December 31, 2025, the attainment year and the 2025 milestone
year coincide.
---------------------------------------------------------------------------

    \345\ 40 CFR 51.1012(a), 51.1013(a)(2).
    \346\ 40 CFR 51.1013(a)(2)(i).
---------------------------------------------------------------------------

    PM2.5 plans should identify budgets for direct
PM2.5, NOX, and all other PM2.5
precursors for which on-road emissions are determined to significantly
contribute to PM2.5 levels in the area for each RFP
milestone year and the attainment year, if the plan demonstrates
attainment. All direct PM2.5 SIP budgets should include
direct PM2.5 motor vehicle emissions from tailpipes, brake
wear, and tire wear. With respect to PM2.5 from re-entrained
road dust and emissions of VOC, SO2, and/or ammonia, the
transportation conformity provisions of 40 CFR part 93, subpart A,
apply only if the EPA Regional Administrator or the director of the
state air agency has made a finding that emissions of these pollutants
within the area are a significant contributor to the PM2.5
nonattainment problem and has so notified the MPO and Department of
Transportation (DOT), or if the applicable implementation plan (or
implementation plan submission) includes any of these pollutants in the
approved (or adequate) budget as part of the RFP, attainment, or
maintenance strategy.\347\
---------------------------------------------------------------------------

    \347\ 40 CFR 93.102(b)(3), 93.102(b)(2)(v), and 93.122(f); see
also Conformity Rule preamble at 69 FR 40004, 40031-36 (July 1,
2004).
---------------------------------------------------------------------------

    In addition, transportation conformity requirements apply with
respect to emissions of NOX unless both the EPA Regional
Administrator and the director of the state air agency have made a
finding that transportation-related emissions of NOX within
the nonattainment area are not a significant contributor to the
PM2.5 nonattainment problem and have so notified the MPO and
DOT, or the applicable implementation plan (or implementation plan
submission) does not establish an approved (or adequate) budget for
such emissions as part of the RFP, attainment, or maintenance
strategy.\348\
---------------------------------------------------------------------------

    \348\ 40 CFR 93.102(b)(2)(iv).
---------------------------------------------------------------------------

    It is not always necessary for states to establish motor vehicle
emissions budgets for all of the PM2.5 precursors. The
PM2.5 SIP Requirements Rule allows a state to demonstrate
that emissions of certain precursors do not contribute significantly to
PM2.5 levels that exceed the NAAQS in a nonattainment area,
in which case the state may exclude such precursor(s) from its control
evaluations for the specific NAAQS at issue. If a state successfully
demonstrates that the emissions of one or more of the PM2.5
precursors from all sources do not contribute significantly to
PM2.5 levels in the subject area, then it is not necessary
to establish motor vehicle emissions budgets for that precursor(s)
consistent with the applicability requirements of the transportation
conformity regulations (40 CFR 93.102(b)(2)(iv) and (v)).\349\
---------------------------------------------------------------------------

    \349\ 81 FR 58010, 58055, 58058, and 58090.
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    Additionally, the transportation conformity regulations contain
criteria for determining whether emissions of one or more
PM2.5 precursors are insignificant for transportation
conformity purposes.\350\ For a pollutant or precursor to be considered
an insignificant contributor based on the transportation conformity
rule's criteria, the control strategy SIP must demonstrate that it
would be unreasonable to expect that such an area would experience
enough motor vehicle emissions growth in that pollutant and/or
precursor for a NAAQS violation to occur. Insignificance determinations
are based on factors such as air quality, SIP-approved motor vehicle
control measures, trends and projections of motor vehicle emissions,
and the percentage of the total attainment plan emissions inventory for
the NAAQS at issue that is comprised of motor vehicle emissions. The
EPA's explanation for providing for insignificance determinations is
described in the July 1, 2004 revision to the Transportation Conformity
Rule.\351\
---------------------------------------------------------------------------

    \350\ 40 CFR 93.109(f).
    \351\ 69 FR 40004.
---------------------------------------------------------------------------

    Transportation conformity trading mechanisms are allowed under 40
CFR 93.124 where a state establishes appropriate mechanisms for such
trades. The basis for the trading mechanism is the SIP attainment
modeling that establishes the relative contribution of each
PM2.5 precursor pollutant. The applicability of emission
trading between conformity budgets for conformity purposes is described
in 40 CFR 93.124(c).
    The EPA's process for determining the adequacy of a budget consists
of three basic steps: (1) Notifying the public of a SIP submittal; (2)
providing the public the opportunity to comment on the budgets during a
public comment period; and (3) making a finding of adequacy or
inadequacy.\352\ The EPA can notify the public by either posting an
announcement that the EPA has received SIP budgets on the EPA's
adequacy website (40 CFR 93.118(f)(1)), or through a Federal Register
notice of proposed rulemaking when the EPA reviews the adequacy of an
implementation plan budget simultaneously with its review and action on
the SIP itself (40 CFR 93.118(f)(2)).
---------------------------------------------------------------------------

    \352\ 40 CFR 93.118(f).

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

Summary of State's Submission
    The 2018 PM2.5 Plan includes budgets for direct
PM2.5 and NOX emissions for the 2019 and 2022 RFP
milestone years, the projected attainment year (2025), and one post-
attainment year quantitative milestone (2028).\353\ The Plan
establishes separate direct PM2.5 and NOX subarea
budgets for each county, or partial county (for Kern County), in the
SJV.\354\ CARB calculated the budgets using EMFAC2014,\355\ CARB's
latest version of the EMFAC model for estimating emissions from on-road
vehicles operating in California that was approved by EPA at the time
of Plan development, and the latest modeled vehicle miles traveled and
speed distributions from the SJV MPOs from the Final 2017 Federal
Transportation Improvement Plans, adopted in September 2016. The
budgets reflect annual average emissions consistent with the annual
averaging period of the 2012 annual PM2.5 NAAQS and the 2018
PM2.5 Plan's RFP demonstration.
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    \353\ 2018 PM2.5 Plan, App. D, Table 3-3.
    \354\ 40 CFR 93.124(c) and (d).
    \355\ 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. 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.
---------------------------------------------------------------------------

    The required budget years applicable to the Serious area plan
portion of the 2018 PM2.5 Plan for the 2012 annual
PM2.5 NAAQS are 2022 and 2025. In our previous final rule on
the State's Moderate area plan for the 2012 annual PM2.5
NAAQS, we approved the budgets for the 2022 RFP milestone year and,
therefore, will not be acting on them again in this action.\356\
However, we include them as a reference point, given our discussion of
the 2022 year in section IV.G of this proposed rule. Also, while the
Plan includes budgets for 2019, consistent with our final rule on the
Moderate area plan, we are not evaluating the 2019 budgets because
budgets for that year would not be used in any future conformity
determination because the plan contains budgets for 2022 and other
years in the future, and because they are not required for the
submitted Serious area plan.
---------------------------------------------------------------------------

    \356\ 86 FR 67343, 67346.
---------------------------------------------------------------------------

    Furthermore, the EPA would begin the motor vehicle emissions budget
adequacy and approval review processes for the 2028 post-attainment
milestone year budgets only if the area fails to attain the standard by
December 31, 2025 (the applicable Serious area attainment date if the
EPA were to finalize approval of the 2018 PM2.5 Plan's
attainment demonstration). If found adequate or approved, that would
result in the 2028 budgets being used in future transportation
conformity determinations in any area that needed additional emissions
reductions to attain the PM2.5 NAAQS.
    The direct PM2.5 budgets include tailpipe, brake wear,
and tire wear emissions but do not include paved road dust, unpaved
road dust, and road construction dust emissions.\357\ The State did not
include budgets for VOC, SO2, or ammonia. As discussed in
section IV.B of this proposed rule, the State submitted a
PM2.5 precursor demonstration documenting that control of
these precursors would not significantly contribute to attainment of
the 2012 annual PM2.5 NAAQS, and the EPA is proposing to
approve the precursor demonstration. Therefore, if the EPA approves the
demonstration, consistent with the transportation conformity regulation
(40 CFR 93.102(b)(2)(v)), the State would not be required to submit
budgets for these precursors. The State also included a discussion of
the significance/insignificance factors for ammonia, SO2,
and VOC, which would demonstrate a finding of insignificance under the
transportation conformity rule.\358\ The State is not required to
include re-entrained road dust in the budgets under section
93.103(b)(3) unless the EPA or the State has made a finding that these
emissions are significant. Neither the State nor the EPA has made such
a finding. The Plan does include a discussion of the significance/
insignificance factors for re-entrained road dust.\359\ The budgets
included in the 2018 PM2.5 Plan are shown in Table 9 of this
proposed rule.
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    \357\ 2018 PM2.5 Plan, App. D, D-122 to D-123.
    \358\ 40 CFR 93.109(f).
    \359\ 2018 PM2.5 Plan, App. D, D-121 and D-122.

         Table 9--Motor Vehicle Emission Budgets for the San Joaquin Valley for the 2012 PM2.5 Standard
                                              [Annual average, tpd]
----------------------------------------------------------------------------------------------------------------
                                                        2022 (RFP year) \a\           2025 (attainment year)
                     County                      ---------------------------------------------------------------
                                                       PM2.5            NOX            PM2.5            NOX
----------------------------------------------------------------------------------------------------------------
Fresno..........................................             0.9            21.2             0.8            14.3
Kern............................................             0.8            19.4             0.8            12.8
Kings...........................................             0.2             4.1             0.2             2.7
Madera..........................................             0.2             3.5             0.2             2.3
Merced..........................................             0.3             7.6             0.3             5.0
San Joaquin.....................................             0.6            10.0             0.6             6.9
Stanislaus......................................             0.4             8.1             0.4             5.6
Tulare..........................................             0.4             6.9             0.4             4.7
----------------------------------------------------------------------------------------------------------------
Source: 2018 PM2.5 Plan, Appendix D, Table 3-3. Budgets are rounded to the nearest tenth of a ton.
\a\ The EPA has already approved the 2022 RFP budgets in our final rule on the State's Moderate area plan for
  the 2012 annual PM2.5 NAAQS in the SJV.

    In the submittal letter for the 2018 PM2.5 Plan, CARB
requested that the EPA limit the duration of the approval of the
budgets to the period before the effective date of the EPA's adequacy
finding for any subsequently submitted budgets.\360\
---------------------------------------------------------------------------

    \360\ Letter dated May 9, 2019, from Richard W. Corey, Executive
Officer, CARB to Mike Stoker, Regional Administrator, EPA Region IX,
3.
---------------------------------------------------------------------------

    The 2018 PM2.5 Plan also includes a proposed trading
mechanism for transportation conformity analyses that would allow
future decreases in NOX emissions from on-road mobile
sources to offset any on-road increases in direct PM2.5
emissions. In the 2018 PM2.5 Plan, the approximate weighting
ratios of the precursor emissions for annual average PM2.5
formation in equivalent tons per

day of NOX are: 6.5:1 (i.e., reducing 6.5 tons of
NOX is equivalent to reducing one ton of PM2.5).
The ratio is based on a sensitivity analysis based on a 30% reduction
of NOX or PM2.5 emissions and the corresponding
impact on design values at sites in Bakersfield and Fresno.
    To ensure that the trading mechanism does not affect the ability of
the SJV to meet the NOX budget, the NOX emission
reductions available to supplement the PM2.5 budget would
only be those remaining after the NOX budget has been
met.\361\ The Plan also provides that the SJV MPOs shall clearly
document the calculations used in the trading, along with any
additional reductions of NOX and PM2.5 emissions
in the conformity analysis.
---------------------------------------------------------------------------

    \361\ 2018 PM2.5 Plan, App. D, D-126 and D-127.
---------------------------------------------------------------------------

EPA Evaluation and Proposed Action
    The EPA generally first conducts a preliminary review of budgets
submitted with an attainment or maintenance plan for PM2.5
for adequacy, prior to taking action on the plan itself, and did so
with respect to the PM2.5 budgets in the 2018
PM2.5 Plan. On June 18, 2019, the EPA announced the
availability of the 2018 PM2.5 Plan with budgets and a 30-
day public comment period. This announcement was posted on the EPA's
Adequacy website at: https://www.epa.gov/state-and-local-transportation/state-implementation-plans-sip-submissions-currently-under-epa. The comment period for this notification ended on July 18,
2019. We did not receive any comments during this comment period.
    Based on our proposal to approve the State's demonstration that
emissions of ammonia, SO2, and VOCs do not contribute
significantly to PM2.5 levels that exceed the 2012 annual
PM2.5 NAAQS in the SJV, as discussed in section IV.B of this
preamble, and the information about ammonia, SO2, and VOC
emissions in the Plan, the EPA proposes to find that it is not
necessary to establish motor vehicle emissions budgets for
transportation-related emissions of ammonia, SO2, and VOC to
attain the 2012 annual PM2.5 NAAQS in the SJV.\362\ Based on
the information about re-entrained road dust in the Plan and in
accordance with 40 CFR 93.102(b)(3), the EPA proposes to find that it
is not necessary to include re-entrained road dust emissions in the
budgets for 2012 annual PM2.5 NAAQS in the SJV.
---------------------------------------------------------------------------

    \362\ 40 CFR 93.102(b)(2)(v).
---------------------------------------------------------------------------

    For the reasons discussed in sections IV.G and IV.F of this
proposed rule, the EPA is proposing to approve the RFP and attainment
demonstrations, respectively, in the 2018 PM2.5 Plan. The
2025 budgets for RFP and attainment, as shown in Table 9 of this
proposed rule, are consistent with these demonstrations, are clearly
identified and precisely quantified, and meet all other applicable
statutory and regulatory requirements including the adequacy criteria
in 40 CFR 93.118(e)(4) and (5). For these reasons, the EPA proposes to
approve the 2025 budgets listed in Table 9. We provide a more detailed
discussion in section VI of the EPA's 2012 Annual PM2.5 TSD.
    As discussed in section IV.I.2 of this proposed rule, we have
already approved the 2022 RFP budgets for the SJV as part of our final
rule on the State's Moderate area plan for the 2012 annual
PM2.5 NAAQS, as supplemented by the 2018 PM2.5
Plan. The budgets that the EPA is proposing to approve relate to the
2012 annual PM2.5 NAAQS only, and our proposed approval does
not affect the status of the previously-approved budgets for the 1997
PM2.5 NAAQS and related trading mechanism, which remain in
effect for that PM2.5 NAAQS, nor the 2006 24-hour
PM2.5 NAAQS and related trading mechanism, which remain in
effect for that PM2.5 NAAQS.\363\
---------------------------------------------------------------------------

    \363\ 76 FR 69896, 69923-69924 (final rule approving direct
PM2.5 and NOX budgets for 2012 and 2014 for
the 1997 annual and 24-hour PM2.5 NAAQS); and 85 FR
44192, 44204 (final rule approving direct PM2.5 and
NOX budgets for 2020, 2023, and 2024 for the 2006 24-hour
PM2.5 NAAQS). The EPA has also proposed to approve
budgets from the 2018 PM2.5 Plan for direct
PM2.5 and NOX for 2017 and 2020 for the 1997
24-hour PM2.5 NAAQS. 86 FR 53150, 53176-53179.
---------------------------------------------------------------------------

    As noted above, the State included a trading mechanism to be used
in transportation conformity analyses that would be used in conjunction
with the budgets in the 2018 PM2.5 Plan, as allowed for
under 40 CFR 93.124(b). This trading mechanism would allow future
decreases in NOX emissions from on-road mobile sources to
offset any on-road increases in PM2.5, using a 6.5:1
NOX:PM2.5 ratio. To ensure that the trading
mechanism does not affect the ability to meet the NOX
budget, the Plan provides that the NOX emission reductions
available to supplement the PM2.5 budget would only be those
remaining after the NOX budget has been met. The SJV MPOs
will have to document clearly the calculations used in the trading when
demonstrating conformity, along with any additional reductions of
NOX and PM2.5 emissions in the conformity
analysis. The trading calculations must be performed prior to the final
rounding to demonstrate conformity with the budgets.
    The EPA has reviewed the trading mechanism as described on pages D-
125 through D-127 in Appendix D of the 2018 PM2.5 Plan and
concludes that it is appropriate for transportation conformity purposes
in the SJV for the 2012 annual PM2.5 NAAQS. The methodology
for estimating the trading ratio for conformity purposes is essentially
an update (based on newer modeling) of the approach that the EPA
previously approved for the 2008 PM2.5 Plan for the 1997
PM2.5 NAAQS \364\ and the 2012 PM2.5 Plan for the
2006 24-hour PM2.5 NAAQS.\365\ The State's approach in the
previous plans was to model the ambient PM2.5 effect of
areawide NOX emissions reductions and of areawide direct
PM2.5 reductions, and to express the ratio of these modeled
sensitivities as an inter-pollutant trading ratio.
---------------------------------------------------------------------------

    \364\ 80 FR 1816, 1841 (January 13, 2015) (noting the EPA's
prior approval of motor vehicle emissions budgets for the 1997
annual and 24-hour PM2.5 standards in the 2008
PM2.5 Plan at 76 FR 69896).
    \365\ 81 FR 59876 (August 31, 2016).
---------------------------------------------------------------------------

    In the updated analysis for the 2018 PM2.5 Plan, the
State completed separate sensitivity analyses for the annual and 24-
hour standards and modeled only transportation-related sources in the
nonattainment area. The ratio the State is proposing to use for
transportation conformity purposes is derived from air quality modeling
that evaluated the effect of reductions in transportation-related
NOX and PM2.5 emissions in the SJV on ambient
concentrations at the Bakersfield-California Avenue, Bakersfield-Planz,
Fresno-Garland, and Fresno-Hamilton & Winery monitoring sites. The
modeling that the State performed to evaluate the effectiveness of
NOX and PM2.5 reductions on ambient annual
concentrations showed NOX:PM2.5 ratios that range
from a high of 7.1 at the Bakersfield-California Avenue monitor to a
low of 6.0 at the two Fresno monitors.\366\ We consider that the
State's approach is a reasonable method to use to develop ratios for
transportation conformity purposes. We therefore propose to approve the
6.5:1 NOX for PM2.5 trading mechanism as
enforceable components of the transportation conformity program for the
SJV for the 2012 annual PM2.5 NAAQS.
---------------------------------------------------------------------------

    \366\ 2018 PM2.5 Plan, App. D, D-126.
---------------------------------------------------------------------------

    Under the transportation conformity rule, once budgets are
approved, they cannot be superseded by revised budgets submitted for
the same CAA purpose and the same year(s) addressed by the previously
approved SIP until the EPA approves the revised budgets as a SIP
revision. As a general matter, such approved budgets cannot be
superseded

by revised budgets found adequate, but rather only through approval of
the revised budgets, unless the EPA specifies otherwise in its approval
of a SIP by limiting the duration of the approval to last only until
subsequently submitted budgets are found adequate.\367\
---------------------------------------------------------------------------

    \367\ 40 CFR 93.118(e)(1).
---------------------------------------------------------------------------

    In the submittal letter for the 2018 PM2.5 Plan, CARB
requested that we limit the duration of our approval of the budgets to
the period before the effective date of the EPA's adequacy finding for
any subsequently submitted budgets.\368\ However, CARB recently
clarified that since they have submitted EMFAC2021 for EPA review, they
no longer request that we limit the duration of our approval.\369\
---------------------------------------------------------------------------

    \368\ Letter dated May 9, 2019, from Richard W. Corey, Executive
Officer, CARB, to Mike Stoker, Regional Administrator, EPA Region
IX, 3.
    \369\ Email dated November 30, 2021, from Nesamani Kalandiyur,
Manager, Transportation Analysis Section, Sustainable Transportation
and Communities Division, CARB, to Karina O'Connor, Air Planning
Office, EPA Region IX.
---------------------------------------------------------------------------

    Lastly, in section IV.H of this proposed rule, the EPA is proposing
to disapprove the contingency measure element of the 2018
PM2.5 Plan with respect to the Serious area requirements for
the 2012 annual PM2.5 NAAQS. If the EPA were to finalize the
proposed disapproval of the 2012 annual PM2.5 NAAQS Serious
area contingency measure element, the area would be eligible for a
protective finding under the transportation conformity rule because the
2018 PM2.5 Plan reflects adopted control measures that fully
satisfy the emissions reductions requirements for the RFP and
attainment year of 2025.\370\
---------------------------------------------------------------------------

    \370\ 40 CFR 93.120(a)(3).
---------------------------------------------------------------------------

Summary of Proposed Actions and Request for Public Comment

    For the reasons discussed in this proposed rule, under CAA section
110(k)(3), the EPA proposes to approve, as a revision to the California
SIP, the following portions of the SJV PM2.5 Plan for the
2012 annual PM2.5 NAAQS to address the CAA's Serious area
planning requirements in the SJV nonattainment area:
    1. The 2013 base year emission inventories (CAA section 172(c)(3)
and 40 CFR 51.1008(b));
    2. the demonstration that BACM, including BACT, for the control of
direct PM2.5 and PM2.5 plan precursors will be
implemented no later than 4 years after the area was reclassified (CAA
section 189(b)(1)(B) and 40 CFR 51.1010(a));
    3. the demonstration (including air quality modeling) that the Plan
provides for attainment as expeditiously as practicable but no later
than December 31, 2025 (CAA sections 189(b)(1)(A) and 40 CFR
51.1011(b));
    4. plan provisions that require RFP toward attainment by the
applicable date (CAA section 172(c)(2) and 40 CFR 51.1012(a));
    5. quantitative milestones that are to be achieved every three
years until the area is redesignated attainment and that demonstrate
RFP toward attainment by the applicable attainment date (CAA section
189(c) and 40 CFR 51.1013(a)(2)(i));
    6. motor vehicle emissions budgets for 2025 as shown in Table 9 of
this proposed rule (CAA section 176(c) and 40 CFR part 93, subpart A);
and
    7. the inter-pollutant trading mechanism provided for use in
transportation conformity analyses for the 2012 annual PM2.5
NAAQS, in accordance with 40 CFR 93.124(b).
    We may, however, reconsider this proposal if, based on new
information or public comments, we find that the State has not
satisfied the statutory criteria for Serious area PM2.5
plans.
    Pursuant to CAA section 110(k)(3), the EPA proposes to disapprove
the contingency measure element of the 2018 PM2.5 Plan for
the 2012 annual PM2.5 NAAQS, as implemented by section 5.7.3
of District Rule 4901, under CAA section 179(c)(9) and 40 CFR 51.1014.
Among other reasons, the element includes no specific measures to be
undertaken if the state fails to submit a quantitative milestone report
for the area, or if the area fails to meet RFP or a quantitative
milestone. In addition, the element includes a specific measure
(section 5.7.3 of District Rule 4901) that may not result in any
emissions reductions following a failure to attain the 2012 annual
PM2.5 NAAQS by the applicable attainment date under certain
circumstances.
    If we finalize the disapproval of the contingency measure element
as proposed, the offset sanction in CAA section 179(b)(2) would apply
in the SJV 18 months after the effective date of a final disapproval,
and the highway funding sanctions in CAA section 179(b)(1) would apply
in the area six months after the offset sanction is imposed.\371\
Neither sanction will be imposed under the CAA if the State submits and
we approve, prior to the implementation of the sanctions, a SIP
revision that corrects the deficiencies that we identify in our final
action. The EPA intends to work with CARB and the SJVUAPCD to correct
the deficiencies in a timely manner.
---------------------------------------------------------------------------

    \371\ 40 CFR 52.31.
---------------------------------------------------------------------------

    In addition to the sanctions, CAA section 110(c)(1) provides that
the EPA must promulgate a federal implementation plan (FIP) addressing
any disapproved elements of an attainment plan two years after the
effective date of disapproval unless the State submits, and the EPA
approves, a SIP submission that cures the disapproved elements.
    Also, we previously approved the Serious area plan RFP and
attainment demonstrations and the motor vehicle emissions budgets for
the 2006 24-hour PM2.5 NAAQS \372\ and the Moderate area
plan RACM, additional reasonable measures, and RFP demonstrations.\373\
In this proposed rule, we are proposing to approve the Serious area
plan BACM/BACT, RFP, and attainment demonstrations, and motor vehicle
emission budgets for the 2012 annual PM2.5 NAAQS. Because of
those actions, we are proposing to issue a protective finding under 40
CFR 93.120(a)(3) to the disapproval of the contingency measure element.
---------------------------------------------------------------------------

    \372\ 85 FR 44192.
    \373\ 86 FR 67343, 67346.
---------------------------------------------------------------------------

    Without a protective finding, the final disapprovals would result
in a conformity freeze, under which only projects in the first four
years of the most recent conforming Regional Transportation Plans
(RTPs) and Transportation Improvement Programs (TIPs) can proceed.
Generally, during a freeze, no new RTPs, TIPs, or RTP/TIP amendments
can be found to conform until another control strategy implementation
plan revision fulfilling the same CAA requirements is submitted, the
EPA finds its motor vehicle emissions budget(s) adequate pursuant to
Sec.  93.118 or approves the submission, and conformity to the
implementation plan revision is determined.\374\ Under a protective
finding, the final disapproval of the contingency measures elements
would not result in a transportation conformity freeze in the SJV
PM2.5 nonattainment area and the MPOs may continue to make
transportation conformity determinations.
---------------------------------------------------------------------------

    \374\ 40 CFR 93.120(a)(2).
---------------------------------------------------------------------------

    We will accept comments from the public on these proposals for the
next 30 days. The deadline and instructions for submission of comments
are provided in the DATES and ADDRESSES sections at the beginning of
this proposed rule.

VI. Statutory and Executive Order Reviews

    Additional information about these statutes and Executive Orders
can be found at https://www.epa.gov/laws-regulations/laws-and-executive-orders.

A. Executive Order 12866: Regulatory Planning and Review and Executive
Order 13563: Improving Regulation and Regulatory Review

    This action is not a significant regulatory action and was
therefore not submitted to the Office of Management and Budget (OMB)
for review.

B. Paperwork Reduction Act (PRA)

    This action does not impose an information collection burden under
the PRA because this action does not impose additional requirements
beyond those imposed by state law.

C. Regulatory Flexibility Act (RFA)

    I certify that this action will not have a significant economic
impact on a substantial number of small entities under the RFA. This
action will not impose any requirements on small entities beyond those
imposed by state law.

D. Unfunded Mandates Reform Act (UMRA)

    This action does not contain any unfunded mandate as described in
UMRA, 2 U.S.C. 1531-1538, and does not significantly or uniquely affect
small governments. This action does not impose additional requirements
beyond those imposed by state law. Accordingly, no additional costs to
state, local, or tribal governments, or to the private sector, will
result from this action.

E. Executive Order 13132: Federalism

    This action does not have federalism implications. It will not have
substantial direct effects on the states, on the relationship between
the national government and the states, or on the distribution of power
and responsibilities among the various levels of government.

F. Executive Order 13175: Coordination With Indian Tribal Governments

    This action does not have tribal implications, as specified in
Executive Order 13175, because the SIP is not approved to apply on any
Indian reservation land or in any other area where the EPA or an Indian
tribe has demonstrated that a tribe has jurisdiction, and will not
impose substantial direct costs on tribal governments or preempt tribal
law. Thus, Executive Order 13175 does not apply to this action.

G. Executive Order 13045: Protection of Children From Environmental
Health Risks and Safety Risks

    The EPA interprets Executive Order 13045 as applying only to those
regulatory actions that concern environmental health or safety risks
that the EPA has reason to believe may disproportionately affect
children, per the definition of ``covered regulatory action'' in
section 2-202 of the Executive Order. This action is not subject to
Executive Order 13045 because it does not impose additional
requirements beyond those imposed by state law.

H. Executive Order 13211: Actions That Significantly Affect Energy
Supply, Distribution, or Use

    This action is not subject to Executive Order 13211, because it is
not a significant regulatory action under Executive Order 12866.

I. National Technology Transfer and Advancement Act (NTTAA)

    Section 12(d) of the NTTAA directs the EPA to use voluntary
consensus standards in its regulatory activities unless to do so would
be inconsistent with applicable law or otherwise impractical. The EPA
believes that this action is not subject to the requirements of section
12(d) of the NTTAA because application of those requirements would be
inconsistent with the CAA.

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

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

List of Subjects in 40 CFR Part 52

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

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

    Dated: December 16, 2021.
Deborah Jordan,
Acting Regional Administrator, Region IX.
[FR Doc. 2021-27796 Filed 12-28-21; 8:45 am]
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