Document ID: EPA-R09-OAR-2021-0408-0018
Agency: epa
Document Type: Rule
Title: Air Quality State Implementation Plans; Approvals and Promulgations: California; Base Year Emissions Inventories for the 2015 Ozone Standards
Posted Date: 2022-09-29T04:00Z

[Federal Register Volume 87, Number 188 (Thursday, September 29, 2022)]
[Rules and Regulations]
[Pages 59015-59021]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2022-20586]

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 52

[EPA-R09-OAR-2021-0408; FRL-8902-02-R9]

Clean Air Plans; Base Year Emissions Inventories for the 2015 
Ozone Standards; California

AGENCY: Environmental Protection Agency (EPA).

ACTION: Final rule.

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SUMMARY: The Environmental Protection Agency (EPA) is taking final 
action to approve revisions to the California State Implementation Plan 
(SIP) concerning the base year emissions inventories for 18 areas 
designated as nonattainment areas (NAAs) for the 2015 ozone national 
ambient air quality standards (``2015 ozone NAAQS'') submitted on July 
24, 2020. The areas include Amador County, Butte County, Calaveras 
County, Imperial County, Kern County (Eastern Kern), Los Angeles--San 
Bernardino Counties (West Mojave Desert), Los Angeles--South Coast Air 
Basin, Mariposa County, Nevada County (Western part), Riverside County 
(Coachella Valley), Sacramento Metro, San Francisco Bay Area, San 
Joaquin Valley, San Luis Obispo (Eastern part), Sutter Buttes, Tuolumne 
County, Tuscan Buttes, and Ventura County. We are approving these 
revisions under the Clean Air Act (CAA), which establishes emissions 
inventory requirements for all ozone nonattainment areas.

DATES: This rule is effective on October 31, 2022.

ADDRESSES: The EPA has established a docket for this action under 
Docket ID No. EPA-R09-OAR-2021-0408. All documents in the docket are 
listed on the https://www.regulations.gov website. Although listed in 
the index, some information is not publicly available, e.g., 
Confidential Business Information (CBI) or other information whose 
disclosure is restricted by statute. Certain other material, such as 
copyrighted material, is not placed on the internet and will be 
publicly available only in hard copy form. Publicly available docket 
materials are available through https://www.regulations.gov, or please 
contact the person identified in the FOR FURTHER INFORMATION CONTACT 
section for additional availability information. If you need assistance 
in a language other than English or if you are a person with 
disabilities who needs a reasonable accommodation at no cost to you, 
please contact the person identified in the FOR FURTHER INFORMATION 
CONTACT section.

FOR FURTHER INFORMATION CONTACT: Ben Leers, Air Planning Office (AIR-
2), EPA Region IX, 75 Hawthorne Street, San Francisco, CA 94105, (415) 
947-4279, or by email at [email protected].

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

Table of Contents

I. Summary of Proposed Action
II. Public Comments and EPA Responses
    A. Comments From Private Individuals
    B. Comment From Center for Biological Diversity
III. Final Action
IV. Statutory and Executive Order Reviews

I. Summary of Proposed Action

    On October 5, 2021, in accordance with CAA sections 172(c)(3) and 
182(a)(1), the EPA proposed to approve a July 27, 2020 SIP submittal 
from the California Air Resources Board (CARB) to address the ozone-
related emissions inventory requirements for the following 18 ozone 
nonattainment areas for the 2015 ozone NAAQS: Amador County, Butte 
County, Calaveras County, Imperial County, Kern County (Eastern Kern), 
Los Angeles--San Bernardino Counties (West Mojave Desert), Los 
Angeles--South Coast Air Basin, Mariposa County, Nevada County (Western 
part), Riverside County (Coachella Valley), Sacramento Metro, San 
Francisco Bay Area, San Joaquin Valley, San Luis Obispo (Eastern part), 
Sutter Buttes, Tuolumne County, Tuscan Buttes, and Ventura County.\1\ 
We refer to our October 5, 2021 proposed rulemaking as the ``proposed 
rule.''
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    \1\ 86 FR 54887 (October 5, 2021).
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    On October 28, 2021, the EPA extended the comment period for the 
proposed rule by 30 days in response to a stakeholder request for an 
extension.\2\ The original deadline to submit comments was November 4, 
2021. This action extended the comment period to December 6, 2021.
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    \2\ 86 FR 59678 (October 28, 2021).
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    In our proposed rule, we provided background information on the 
2015 ozone standards, area designations in

[[Page 59016]]

California, and related base year emissions inventory SIP revision 
requirements under the CAA and the EPA's implementing regulations for 
the 2015 ozone standards, referred to as the 2015 ozone SIP 
Requirements Rule (``2015 Ozone SRR'').\3\
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    \3\ ``Implementation of the 2015 National Ambient Air Quality 
Standards for Ozone: Nonattainment Area State Implementation Plan 
Requirements,'' Final Rule, 83 FR 62998 (December 6, 2018).
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    On July 27, 2020, the California Air Resources Board (CARB) 
submitted the ``70 ppb Ozone SIP Submittal'' (``2020 CARB SIP 
Submittal'') to the EPA.\4\ As explained in our proposed rule, the 2020 
CARB SIP Submittal contains a staff report with a release date of May 
22, 2020, and attachments of emissions inventories that address base 
year inventory requirements for 18 of the 21 NAAs in California.\5\ In 
our proposed rule, we provided a summary of the 2020 CARB SIP 
Submittal, evaluated the submittal for compliance with statutory and 
regulatory requirements, and proposed to find that the submittal meets 
all applicable requirements.
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    \4\ Letter dated July 24, 2020, from Richard W. Corey, Executive 
Officer, CARB, to John Busterud, Regional Administrator, EPA Region 
IX (submitted electronically July 27, 2020).
    \5\ CARB's submittal does not include the San Diego NAA, which 
was submitted separately via the State Planning Electronic 
Collaboration System (SPeCS) for SIPs on January 12, 2021. The EPA 
will take action on the emissions inventory for the San Diego NAA in 
a separate rulemaking. Because the State of California does not have 
regulatory authority over the Pechanga and Morongo NAAs, CARB's 
submittal does not include emissions inventories for these areas.
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    The emissions inventories we are approving into the SIP in this 
final action are detailed in Table 1 of the proposed rule. The EPA 
finds that CARB developed approvable inventories of oxides of nitrogen 
(NOX) and volatile organic compounds (VOC) emissions for the 
18 ozone nonattainment areas as required under the CAA and 2015 Ozone 
SRR (40 CFR 51.1315; see also CAA section 172(c)(3)).
    Refer to our proposed rule for more information concerning the 
background for this action and for a more detailed discussion of the 
rationale for approval.

II. Public Comments and EPA Responses

    The EPA's proposed rule provided a 30-day public comment period 
that ended on November 4, 2021. As explained in section I of this 
preamble, on October 28, 2021, we extended the comment period by 30 
days to December 6, 2021, in response to a stakeholder request for an 
extension.\6\ We received eight sets of comments, including seven 
comment submissions from private individuals \7\ and one comment letter 
from the Center for Biological Diversity (CBD).\8\ All comments 
received in response to our proposed rulemaking are available in the 
docket for this rulemaking.\9\ Four of the comment submissions from 
private individuals generally support our proposal to approve the 2020 
CARB SIP Submittal as meeting the base year emissions inventory 
requirements.\10\ These four supportive comments do not require a 
response. We respond to the remainder of the comments received on our 
proposed rulemaking in this action.
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    \6\ Email dated October 7, 2021, from Robert Ukeiley, Center for 
Biological Diversity, to Khoi Nguyen, EPA Region IX.
    \7\ Comments from private individuals were made to Docket ID No. 
EPA-R09-OAR-2021-0408 as follows: (1) comment dated October 6, 2021, 
from Saida Lopez Williams; (2) comment dated October 8, 2021, from 
Annie Miller; (3) comment dated October 11, 2021, from Tristan 
Sommers; (4) comment dated October 16, 2021, from Taylor W.; (5) 
comment dated November 3, 2021, from Lindsey H.; (6) comment dated 
November 3, 2021, from Alexander Mata; (7) comment dated November 3, 
2021, from Tom Loch.
    \8\ Letter dated December 1, 2021, from Nathan Donley, Center 
for Biological Diversity, to Docket ID No. EPA-R09-OAR-2021-0408, 
Subject: ``Re: Comments on Clean Air Plans; Base Year Emission 
Inventories for the 2015 Ozone Standards; California (Docket #: EPA-
R09-OAR-2021-0408).''
    \9\ Comments are publicly available at https://www.regulations.gov/docket/EPA-R09-OAR-2021-0408/comments.
    \10\ Docket ID No. EPA-R09-OAR-2021-0408-0011, EPA-R09-OAR-2021-
0408-0014, EPA-R09-OAR-2021-0408-0015, and EPA-R09-OAR-2021-0408-
0016.
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A. Comments From Private Individuals

    Comment A.1: Two private individual commenters \11\ question how 
the proposed rulemaking will improve air pollution in the nonattainment 
areas. Additionally, one of the commenters \12\ suggests that there 
should be a call to action for these nonattainment areas to implement 
some forms of regulation or change in activities to actively pursue 
attainment of environmental goals.
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    \11\ Docket ID No. EPA-R09-OAR-2021-0408-0007 and EPA-R09-OAR-
2021-0408-0008.
    \12\ Docket ID No. EPA-R09-OAR-2021-0408-0008.
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    Response A.1: The EPA appreciates the commenters' questions 
regarding how air pollution will be improved. As explained in our 
proposed rule, CAA section 182(a)(1) and 40 CFR 51.1315 require states 
to develop and submit, as SIP revisions, emissions inventories for all 
areas designated as nonattainment for the 2015 ozone NAAQS. An 
emissions inventory for an ozone nonattainment area is comprised of 
typical weekday actual emissions of ozone precursors in the area's 
ozone season. Emissions inventories provide emissions data for a 
variety of air quality planning tasks, including establishing baseline 
emissions levels (i.e., the level of emissions associated with 
violations of the ozone standards), calculating emissions reduction 
targets needed to attain the NAAQS and to achieve reasonable further 
progress (RFP) toward attainment of the ozone standards, determining 
emissions inputs for ozone air quality modeling analyses, and tracking 
emissions over time to determine progress toward achieving air quality 
and emissions reduction goals.
    The EPA also appreciates the commenters' concerns about 
nonattainment areas needing to actively pursue attainment via 
implementation of regulations or change in activities. The EPA 
promulgates NAAQS for certain air pollutants, such as ozone, under 
section 109 of the CAA. The NAAQS are concentration levels that the EPA 
has determined to be requisite to protect public health and welfare. 
Under CAA section 107(d), the EPA designates areas as nonattainment if 
they are violating the NAAQS or contributing to a violation of the 
NAAQS in nearby areas. State and local governments with nonattainment 
areas must develop implementation plans outlining how these areas will 
attain and maintain the NAAQS by reducing air pollutant emissions. 
Sections 110, 172, and 182 of the CAA require states to develop and 
submit SIPs to implement, maintain, and enforce the NAAQS.\13\ These 
SIPs address requirements for emissions inventories, attainment 
demonstrations, reasonable further progress, reasonably available 
control measures, contingency measures, and motor vehicle emissions 
budgets to improve air quality. Although the base year emissions 
inventories submitted pursuant to CAA sections 172(c)(3) and 182(a)(1) 
are not intended to result directly in reductions of emissions or ozone 
concentration levels, they inform the development and implementation of 
the SIP submittals that are required under the CAA to actively pursue 
attainment of environmental goals, as suggested by the commenter.
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    \13\ For more information on the NAAQS implementation process, 
please see https://www.epa.gov/criteria-air-pollutants/naaqs-implementation-process.
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    Comment A.2: One private individual commenter \14\ suggests that, 
within the requirements for base year inventories, a fifth class of 
anthropogenic sources should be added. The commenter explains that this 
fifth class will cover emissions contributions from agriculture 
livestock, agricultural soils, and rice production. The commenter 
indicates that by adding this fifth class,

[[Page 59017]]

the proposed rule will gain a more thorough overview of ozone creation 
within California, allowing the EPA to make better decisions based on 
nonattainment areas.
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    \14\ Docket ID No. EPA-R09-OAR-2021-0408-0009.
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    Response A.2: As explained in our proposed rule, CAA section 
182(a)(1) and 40 CFR 51.1315 contain the requirements for ozone base 
year emissions inventories. The EPA's guidance for the preparation of 
ozone base year emissions inventories (``EI Guidance'') \15\ also 
indicates that, traditionally, the term ``source category'' has been 
used to identify the major types of emissions inventory groupings: 
stationary point sources, stationary area (or nonpoint) sources, on-
road mobile sources, and nonroad mobile sources.\16\ Accordingly, our 
proposed rule identifies four general classes of anthropogenic sources: 
stationary point sources; area sources; on-road mobile sources; and 
off-road mobile sources.
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    \15\ EPA, ``Emissions Inventory Guidance for Implementation of 
Ozone and Particulate Matter National Ambient Air Quality Standards 
(NAAQS) and Regional Haze Regulations'' (May 2017).
    \16\ EI Guidance, 19.
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    Potentially referring to section A.2 of our proposed rulemaking 
titled ``Requirements for Base Year Inventories,'' the commenter 
proposes that the requirements for base year inventories should be 
amended to add a requirement for a separate category of anthropogenic 
sources encompassing emissions from agriculture livestock, agricultural 
soils, and rice production. The requirements for base year emissions 
inventories established at 40 CFR 51.1315 and at CAA sections 172(c)(3) 
and 182(a)(1) do not define specific ``classes'' of sources in which to 
sort reported emissions. However, we note that the source categories 
cited by the commenter for inclusion in a ``fifth class,'' i.e., 
agricultural livestock, agricultural soils, and rice production, are 
already included in California's base year emissions inventories for 
the 2015 ozone NAAQS. Emissions from these sources are accounted for in 
the 2020 CARB SIP Submittal under diesel agricultural equipment, 
agricultural diesel irrigation pumps, pesticides, farming operations 
(including livestock husbandry), and agricultural 
burning.\17\Additionally, we note that the EPA's EI Guidance addresses 
emissions from agricultural livestock \18\ and from certain 
agricultural soil sources (e.g., direct emissions of pesticides and 
fertilizers \19\) under the area source category. Emissions from rice 
production are addressed under various source categories, including the 
area source category for processes such as direct application of 
pesticides and fertilizers \20\ and the non-road mobile source category 
for mobile agricultural equipment.\21\
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    \17\ 2020 CARB SIP Submittal, Staff Report, 13, 15, 20-22.
    \18\ EI Guidance, 87 and B-1.
    \19\ EI Guidance, 87-88.
    \20\ Id.
    \21\ EI Guidance, 27.
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    Comment A.3: One private individual commenter \22\ expresses 
concerns about the lack of base year emissions inventory updates for 
attainment areas and questions why emissions reductions or new 
emissions standards are not required for attainment areas.
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    \22\ Docket ID No. EPA-R09-OAR-2021-0408-0008.
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    Response A.3: While establishing requirements for nonattainment and 
attainment areas is outside the scope of this rulemaking action, the 
EPA agrees that protection of air quality in all areas is of vital 
importance. We note that the CAA imposes various requirements on 
nonattainment areas for ozone national ambient air quality standards. 
The requirements that apply to ozone nonattainment areas, including the 
requirement for states to submit base year emissions inventories for 
these areas, are established in CAA sections 172 and 182. These 
statutes apply specifically to areas that the EPA has determined to be 
in nonattainment with respect to a NAAQS and are intended to restore 
air quality in these areas to levels that the EPA has determined to be 
requisite to protect public health and welfare with an adequate margin 
for safety. Accordingly, the SIP submittal that the EPA is evaluating 
for this action was submitted to fulfill requirements specific to ozone 
nonattainment areas. The requirements in CAA sections 172 and 182 do 
not apply to areas designated as attainment, and there is no CAA 
requirement for states to submit base year emissions inventories for 
attainment areas.
    We do note, however, that recent emissions information is available 
for all areas of the United States, including attainment areas, in the 
EPA's national emissions inventory (NEI). The NEI contains 
comprehensive and detailed information on air emissions of criteria 
pollutants, criteria pollutant precursors, and hazardous air pollutants 
from air emissions sources nationwide.\23\ The NEI is released every 
three years and is based primarily upon data provided by state, local, 
and tribal air agencies for sources in their jurisdictions in 
accordance with the air emissions reporting requirements (AERR) at 40 
CFR part 51, subpart A. At the state level, CARB also collects and 
provides statewide emissions via the California emissions inventory 
data analysis and reporting system (CEIDARS), which is a database 
management system developed to track statewide criteria pollutant and 
air toxics emissions.\24\ Similarly to the NEI, CEIDARS includes 
emissions information for all areas in California and is not limited to 
nonattainment areas.
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    \23\ For more information on the NEI, please see https://www.epa.gov/air-emissions-inventories/national-emissions-inventory-nei.
    \24\ See https://ww2.arb.ca.gov/criteria-pollutant-emission-inventory-data.
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B. Comment From Center for Biological Diversity

    Comment B.1: CBD asserts that CARB's base year emissions 
inventories must be corrected to account for anthropogenic sources of 
soil-based NOX emissions related to fertilizer and pesticide 
use in California before the EPA may approve the inventories.\25\ 
Throughout its comment letter, CBD refers to soil NOX 
resulting from fertilizer and pesticide use as an anthropogenic 
emissions source. CBD implies that CARB assumes NOX 
emissions from fertilizers and pesticides to be zero and argues that 
doing so is unacceptable and contrary to science. While the commenter 
acknowledges the challenges associated with quantifying NOX 
emissions resulting from fertilizer and pesticide use, they consider 
the quantification of these emissions to be no more complex than CARB's 
quantification of VOC emissions from pesticides in its base year 
emissions inventories. CBD's comment letter discusses the impacts that 
both fertilizer and pesticide use have on NOX emissions and 
cites 13 research manuscripts to support their comment, 11 of which are 
included as attachments to the comment letter.
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    \25\ CBD's comment letter and attachments (``CBD comment'') are 
available at https://www.regulations.gov/ under Docket ID No. EPA-
R09-OAR-2021-0408-0017.

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[[Page 59018]]

    With respect to fertilizer use, the commenter first references two 
studies: one concluding that non-fossil fuel NOX emissions 
should be equally considered as fossil fuel NOX emissions 
when designing NOX pollution mitigation,\26\ and another 
estimating that 600,000 to 800,000 tons of nitrogen from inorganic 
fertilizer were used in California each year between 2000 and 2008.\27\ 
Additionally, the commenter cites a study finding that, while soils are 
always producing background NOX in California, 
NOX production rises considerably in croplands with high 
fertilizer use, and the NOX emitted through soil could 
produce over 50 percent of the atmospheric NOX present in 
rural California regions.\28\ The commenter also references a review of 
studies conducted in California counties to suggest that between 0.2 
and 10.4 percent of the nitrogen applied as fertilizer is emitted as 
NOX, depending on the application method and region.\29\ 
Further, the commenter cites a recent study finding that fertilized 
croplands account for 32 percent of NOX emissions across 
California.\30\ Lastly, the commenter references a study indicating 
that California has measured fluxes in NOX in the San 
Joaquin Valley in the past and correlated these changes with fertilizer 
use.\31\
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    \26\ Song et al. (2021). Important contributions of non-fossil 
fuel nitrogen oxides emissions, Nature Communications, 12(1), 
doi:10.1038/s41467-020-20356-0; available at https://www.nature.com/articles/s41467-020-20356-0.
    \27\ Rosenstock et al. (2013). Nitrogen fertilizer use in 
California: Assessing the data, trends and a way forward, California 
Agriculture, 67(1), 68-79, doi:10.3733/ca.e.v067n01p68; available at 
https://escholarship.org/uc/item/5mk2q1sm.
    \28\ Sha et al. (2021). Impacts of soil NOX emission 
on O3 air quality in rural California, Environmental 
Science & Technology, 55(10), 7113-7122, doi:10.1021/
acs.est.0c06834; available at https://pubs.acs.org/doi/10.1021/acs.est.0c06834.
    \29\ Verhoeven et al. (2017). N2O emissions from 
California farmlands: A review, California Agriculture, 71(3), 148-
159, doi:10.3733/ca.2017a0026; available at https://escholarship.org/uc/item/0kb4505k.
    \30\ Almaraz et al. (2018). Agriculture is a major source of 
NOX pollution in California, Science Advances, 4(1), 
doi:10.1126/sciadv.aao3477, 2018; available at https://advances.sciencemag.org/content/4/1/eaao3477.
    \31\ Matson et al. (1997). Agricultural Systems in the San 
Joaquin Valley: Development of Emissions Estimates for Nitrogen 
Oxides; available at https://ww2.arb.ca.gov/sites/default/files/classic//research/apr/past/94-732.pdf.
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    With respect to pesticide use, the commenter cites two recent 
studies to suggest that pesticides of all types can have negative 
impacts on soil invertebrates or microorganisms by killing or inducing 
sublethal effects on growth, behavior, or reproduction.32 33 
Additionally, the commenter references research studies to suggest that 
the fumigant pesticide chloropicrin was found to increase soil 
NOX emissions by 8-fold and 7-fold in laboratory and field 
conditions, respectively,\34\ that multiple herbicides, one fungicide, 
and one adjuvant all increased NOX emissions in agricultural 
soils two months after crop harvest,\35\ that the herbicide butachlor 
increased NOX emissions from citrus fields by 56-85 
percent,\36\ that application of the insecticide sulfoxaflor to 
greenhouse vegetables drives changes to soil microbial communities 
leading to increased NOX emissions,\37\ and that application 
of the fungicide chlorothalonil has similar impacts to soil microbial 
communities leading to increases of NOX emissions in tea 
fields by 380-830 percent.\38\
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    \32\ Puglisi, E. (2012). Response of microbial organisms 
(aquatic and terrestrial) to pesticides, EFSA Supporting 
Publications, 9(11), doi:10.2903/sp.efsa.2012.en-359; available at 
https://efsa.onlinelibrary.wiley.com/doi/abs/10.2903/sp.efsa.2012.EN-359.
    \33\ Gunstone et al. (2021). Pesticides and soil invertebrates: 
A hazard assessment, Frontiers in Environmental Science, 9, 
doi:10.3389/fenvs.2021.643847; available at https://www.frontiersin.org/articles/10.3389/fenvs.2021.643847/full.
    \34\ Spokas and Wang. (2003). Stimulation of nitrous oxide 
production resulted from soil fumigation with chloropicrin, 
Atmospheric Environment, 37(25), 3501-3507, doi:10.1016/s1352-
2310(03)00412-6; available at https://www.sciencedirect.com/science/article/abs/pii/S1352231003004126.
    \35\ Jezierska-Tys et al. (2021). Microbiological nitrogen 
transformations in soil treated with pesticides and their impact on 
soil greenhouse gas emissions, Agriculture, 11(8), 787, doi:10.3390/
agriculture11080787; available at https://www.mdpi.com/2077-0472/11/8/787.
    \36\ XiangZhou et al. (2018). Effects of herbicides on urea 
nitrogen transformation and greenhouse gas emission of soil in 
citrus orchards with different planting years, Chinese Journal of 
Eco-Agriculture, 26(3), 338-346; available at https://www.cabdirect.org/cabdirect/abstract/20183141714.
    \37\ Fang et al. (2021). Effects of sulfoxaflor on greenhouse 
vegetable soil N2O emissions and its microbial driving 
mechanism, Chemosphere, 267, 129248, doi:10.1016/
j.chemosphere.2020.129248; available at https://pubmed.ncbi.nlm.nih.gov/33321281/.
    \38\ Su et al. (2020). Long-term effects of chlorothalonil on 
microbial denitrification and N2O emission in a tea field 
soil, Environmental Science and Pollution Research, 27(14), 17370-
17381, doi:10.1007/s11356-020-07679-7; available at https://link.springer.com/article/10.1007%2Fs11356-020-07679-7.
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    Response B.1: We appreciate CBD's comment regarding the inclusion 
of soil NOX emissions resulting from fertilizer and 
pesticide use in CARB's 2015 ozone base year emissions inventories. We 
acknowledge the studies cited by CBD in their comment letter finding 
that these types of soil NOX emissions contribute to 
atmospheric NOX levels in California. Particularly, the EPA 
acknowledges the growing body of research surrounding the 
identification and quantification of soil NOX emissions 
induced by fertilizer application in agricultural soils. The EPA 
encourages CARB and the districts governing California's ozone 
nonattainment areas to perform and keep abreast of research on 
NOX emissions from agriculture and their implications for 
air quality modeling and planning. However, as highlighted by our 
discussion in the following paragraphs, in light of EPA guidance and 
regulations related to the classification of emissions sources in base 
year emissions inventories and uncertainties and disagreements among 
studies regarding the contribution of fertilized cropland soils to 
NOX emissions in California, the EPA disagrees with the 
commenter's assertion that the emissions inventories in the 2020 CARB 
SIP Submittal must be amended to account for soil NOX 
emissions before the EPA may approve them as meeting the base year 
emissions inventory requirements for the 2015 ozone NAAQS.
    The 2020 CARB SIP Submittal specifies that the emissions 
inventories in the submittal include only emissions from anthropogenic 
sources, i.e., they do not include biogenic emissions.\39\ CBD's 
comment letter frequently refers to soil NOX from 
agricultural sources as an anthropogenic emissions source, suggesting 
that these soil NOX emissions must be categorized as 
anthropogenic and thereby included in CARB's base year emissions 
inventories. However, the techniques currently available for the 
estimation of soil NOX emissions induced by fertilizer 
application, including the techniques used in the studies cited by CBD 
in its comment letter, present substantial uncertainty and variability 
with respect to the magnitude and proportion of soil NOX 
emissions that can be attributed to agricultural fertilizer 
application. Thus, at this time, we do not find CARB's base year 
emissions inventories to be deficient for not including soil 
NOX as an anthropogenic emissions source.
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    \39\ 2020 CARB SIP Submittal, Staff Report, 8.
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    In its comment letter, CBD acknowledges the ``highly variable'' 
nature of soil NOX emissions and notes that estimating such 
emissions requires data on fertilizer or pesticide use in a particular 
region and is dependent on application method, amount of moisture in 
the soil and ``a whole host of other variables.'' \40\ In a study cited 
by the commenter, Almaraz et al. highlight the uncertainty present in 
the soil NOX estimation techniques relied upon in the

[[Page 59019]]

study.\41\ While Almaraz et al. suggest that soil NOX 
emissions may be significantly underestimated using currently employed 
techniques, the study acknowledges the limited number of surface 
measurements that were available for purposes of comparing the model 
results and that, where observations exist, there is a large range of 
observed values due to varying soil conditions (e.g., relating to 
temperature, moisture, fertilizer application, etc.). The ``top-down'' 
NOX emissions estimates derived from aircraft measurements 
relied upon in the study also reflect a significant degree of 
uncertainty, reported at 190 tons per day plus or minus 130 tons per 
day, i.e., plus or minus 68 percent. The authors acknowledge the 
difficulty in comparing the model results to the observations and note 
the need for more field measurements.
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    \40\ CBD comment, 3.
    \41\ Almaraz et al. (2018).
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    The challenges associated with quantifying the contribution of 
fertilizer application to NOX emissions using currently 
available datasets are also highlighted in a separate study not cited 
by the commenter evaluating the impacts of soil NOX to 
atmospheric levels of particulate matter in the San Joaquin Valley.\42\ 
In this study, Guo et al. expressed that obtaining an emission factor 
correlating NOX emissions to fertilizer application from the 
data available in various studies (including Almaraz et al.) would be 
``difficult or impossible'' due to the sparsity of data collected in 
terms of, sampling length, sampling frequency, and the episodic nature 
of nitrogen gases from soil.
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    \42\ Guo et al. (2020). Assessment of Nitrogen Oxide Emissions 
and San Joaquin Valley PM2.5 Impacts From Soils in 
California, Journal of Geophysical Research: Atmospheres, 125(24), 
doi: 10.1029/2020JD033304; available at https://doi.org/10.1029/2020JD033304, 2.
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    Additionally, estimates of the magnitude of agricultural soil 
NOX emissions in California vary greatly from study to 
study. For example, Almaraz et al. estimated that soil NOX 
emissions from fertilized croplands account for 32 percent of 
NOX emissions across California, Sha et al. estimated soil 
NOX emissions to comprise 40.1 percent of California's total 
NOX emissions, and Guo et al., estimated that soil 
NOX emissions in California equate to only 1.1 percent of 
anthropogenic NOX emissions in the State.\43\ Similarly, 
estimates of the fraction of nitrogen applied as fertilizer released as 
NOX to the atmosphere was estimated by Almaraz et al. to be 
15 percent, while seven other studies reviewed by Guo et al. estimated 
2 percent or less.\44\ Almaraz et al., Sha et al., and Guo et al. each 
evaluated the performance of the soil NOX estimation model 
used in the respective studies by comparing modeled soil NOX 
emissions to observed soil NOX emission values. Sha et al. 
and Guo et al. also used photochemical models to compare the resulting 
predicted NO2 concentrations to satellite observations of 
NO2. Despite producing drastically different estimates of 
the portion of California's NOX emissions inventories 
attributable to soil NOX, each of these studies report high 
agreement between modeled and observed soil NOX 
emissions.\45\ This discrepancy highlights the uncertainty surrounding 
the available observations, given that agreement between modeled and 
observed soil NOX emissions are not sufficient to constrain 
these disparate model results. Thus, at this time, the EPA does not 
believe that available research provides sufficient certainty about the 
magnitude and proportion of soil NOX emissions attributable 
to agricultural fertilizer application for the EPA to require that a 
state categorize these emissions as biogenic or anthropogenic when 
developing its base year emissions inventories.
---------------------------------------------------------------------------

    \43\ Guo et al. (2020).
    \44\ Guo et al. (2020), 7, table 2.
    \45\ For example, in evaluating model performance against 
satellite-observed NO2 observations over croplands, Sha 
et al. reported that the soil NOX estimation technique 
employed in the study decreased mean bias by nearly 23% compared to 
the default model employed by MEGAN version 2.04, concluding that 
the model employed in the study demonstrated ``good agreement'' with 
tropospheric NO2 column observations. Guo et al. 
validated its soil NOX model by comparing modeled values 
to field measurements of soil NOX flux rates in 
croplands, finding that ``the model predicted the measured soil 
NOX emissions closely, with an r\2\ of 0.69 and a p value 
of <0.001, demonstrating again that the model is capable of 
reasonably simulating N speciation and emissions from California 
agricultural ecosystems.''
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    While the base year emissions inventories in the 2020 CARB SIP 
Submittal do not include soil NOX emissions, the EPA 
disagrees with the commenter that CARB has assumed the NOX 
emissions attributed to soils to be zero. Biogenic emissions (including 
soil NOX emissions, if categorized as such) are generally 
accounted for in the modeled attainment demonstrations submitted for 
nonattainment areas as recommended in the EPA's ``Modeling Guidance for 
Demonstrating Air Quality Goals for Ozone, PM2.5 and 
Regional Haze.'' \46\ Modeled attainment demonstrations have not yet 
been submitted to the EPA for California nonattainment areas for the 
2015 ozone NAAQS. However, publicly available draft SIP materials for 
one nonattainment area in California, the Los Angeles-South Coast Air 
Basin, indicate that soil NOX emissions have been quantified 
and will be accounted for in the photochemical modeling relied upon in 
the area's attainment demonstration.\47\ Additionally, CARB has 
accounted for soil NOX emissions in modeled attainment 
demonstrations for recent SIP submittals, including the ``2018 Plan for 
the 1997, 2006, and 2012 PM2.5 Standards'' for the San 
Joaquin Valley (``2018 SJV PM2.5 Plan''),\48\ which shows 
that CARB develops estimates for soil NOX emissions and will 
account for these emissions and their impacts on modeled ozone design 
values in the upcoming attainment plans required for 2015 ozone NAAQS 
nonattainment areas.
---------------------------------------------------------------------------

    \46\ EPA, ``Modeling Guidance for Demonstrating Air Quality 
Goals for Ozone, PM2.5 and Regional Haze'' (November 
2018), section 2.7.7.5.
    \47\ South Coast Air Quality Management District, 2022 Draft Air 
Quality Management Plan, Appendix V, V-4-16, V-4-17. Soil 
NOX emissions are quantified by running the Model of 
Emissions of Gases and Aerosols from Nature version 3.0 (MEGAN3.0), 
which uses the Yienger-Levy model for soil NOX 
production. The Yienger-Levy model includes a linear dependence of 
NOX emission rates on nitrogen fertilizer application 
rate for agricultural soils and accounts for NOX emission 
pulses observed following the wetting of dry soils. See Yienger, 
J.J.; Levy, H. Empirical model of global soil-biogenic 
NOX emissions. J. Geophys. Res. 1995, 100, 11447-11464.
    \48\ See the EPA's ``Response to Comments Document for the EPA's 
Final Action on the San Joaquin Valley Serious Area Plan for the 
2006 PM2.5 NAAQS'' (June 2020), 149-150. Upon reviewing 
the 2018 SJV PM2.5 Plan, the EPA determined that 
California used the Model of Emissions of Gases and Aerosols from 
Nature (MEGAN) and the Model for Ozone and Related chemical Tracers, 
version 4 (MOZART-4) to generate inputs for photochemical models 
relied upon in the 2018 SJV Plan. MEGAN and MOZART-4 each include 
models to estimate soil NOX emissions. The EPA confirmed 
with CARB that the photochemical modeling in the 2018 SJV 
PM2.5 Plan accounted for soil NOX emissions 
from agricultural sources.
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    Consistent with applicable emissions inventory requirements and EPA 
guidance, the EPA generally grants flexibility to states in preparing 
their base year emissions inventories to comport with the structure and 
feasibility of their emissions collecting mechanisms, including with 
respect to the allocation of an emissions source to a particular source 
category. The requirements for base year emissions inventories in CAA 
sections 172(c)(3) and 182(a)(1) and at 40 CFR 51.1315 do not include 
requirements pertaining to the allocation of emissions to source 
categories, and the EPA's EI Guidance does not suggest whether 
agricultural soil NOX emissions should be categorized as an 
anthropogenic emissions source.\49\ The EPA generally

[[Page 59020]]

grants discretion to states to allocate emissions sources to source 
categories as they deem appropriate for the development of their 
emissions inventory SIP submittals. Additionally, the EPA's national 
emissions inventory also does not distinguish naturally occurring soil 
NOX emissions from fertilizer-induced soil NOX 
emissions, and it categorizes soil NOX emissions as a 
biogenic emissions source in name, because emissions are generated from 
the Biogenic Emissions Inventory System model.50 51 Thus, we 
find it acceptable that CARB did not include soil NOX 
emissions as an anthropogenic emissions source in the 2020 CARB SIP 
Submittal.
---------------------------------------------------------------------------

    \49\ EI Guidance, 100-101. ``Biogenic sources are a subset of 
natural emissions sources that may contribute significantly to an 
emissions inventory. Vegetation (i.e., forests and agriculture) is 
the predominant biogenic source of VOC and is typically the only 
source that is included in a biogenic VOC emissions inventory. 
Microbial activity in the soil contributes to natural biogenic 
NOX and CO emissions.''
    \50\ See 2017 National Emissions Inventory Technical Support 
Document (TSD), section 4.4 Agriculture--Fertilizer Application, 4-
49--4-56 (January 2021).
    \51\ The EPA's EI Guidance clarifies that source category 
groupings relate more to how emissions inventory data are created 
than to the features of the actual emissions sources included in the 
category. See EI Guidance, 19. For the purpose of the national 
emissions inventory, soil NOX emissions are calculated 
using the Biogenic Emissions Inventory System, a model that produces 
estimates of total soil NOX emissions that are not 
disaggregated into anthropogenic and biogenic contributions. Thus, 
the classification of soil NOX emissions as biogenic in 
the NEI is a matter of practicality rather than a policy statement.
---------------------------------------------------------------------------

    With respect to the impact of pesticides on soil NOX 
emissions, CBD's comment letter cites numerous studies to suggest that 
pesticide application increases NOX emissions from soils. We 
note that each of these studies correlates pesticide use to nitrous 
oxide (N2O) emissions rather than NOX emissions. 
These studies include Verhoeven et al. (2017), Spokas and Wang (2003), 
Jezierska-Tys et al. (2021), XiangZhou et al. (2018), Fang et al. 
(2021), and Su et al. (2020). These studies do not review pesticide 
impacts on NOX emissions, nor do they relate soil 
N2O emissions to NOX emissions. While 
N2O is known to contribute to greenhouse climate warming 
effects and atmospheric ozone depletion, N2O is not known to 
be active in the chemical processes contributing to ground-level ozone 
production and is relatively inert in the troposphere.\52\ It is 
therefore not included in the EPA's definition for NOX.\53\ 
Because the studies cited by the commenter do not correlate pesticide 
use (or the resultant N2O emissions) to NOX 
emissions, the EPA disagrees that the information provided by the 
commenter suggests that CARB's emissions inventories must be modified 
to include NOX emissions resulting from pesticide 
application.
---------------------------------------------------------------------------

    \52\ Seinfeld, J., & Pandis, S. (2016). ``Atmospheric Chemistry 
and Physics: From Air Pollution to Climate Change,'' John Wiley & 
Sons, 28.
    \53\ Per 40 CFR 51.1300, ``Nitrogen Oxides (NOX) 
means the sum of nitric oxide and nitrogen dioxide in the flue gas 
or emission point, collectively expressed as nitrogen dioxide.''
---------------------------------------------------------------------------

    The EPA does not find that CARB assumed NOX emissions 
from fertilizers to be zero in its base year emissions inventories. 
Rather, the EPA understands that CARB included only anthropogenic 
emissions in its base year inventories and therefore did not include 
soil NOX emissions in the base year inventories as a result 
of considering those emissions to be biogenic. Upon review of 
applicable statutes and regulations, EPA guidance, studies cited by the 
commenter, and additional research, the EPA does not find that it must 
require a particular categorization of soil NOX emissions in 
base year emissions inventories at this time. Furthermore, 
documentation related to various California area SIPs indicates that 
CARB accounts for NOX emissions resulting from fertilizer 
application in its attainment demonstration modeling for nonattainment 
areas. The studies cited by the commenter related to pesticide 
application address N2O emissions rather than NOX 
emissions and thus do not indicate that CARB's emissions inventories 
should be modified to include NOX emissions resulting from 
pesticide application. For these reasons, we conclude that the 
emissions inventories in CARB's submittal do not need to be amended 
before the EPA may approve them as meeting the applicable base year 
emissions inventory requirements.

III. Final Action

    The comments submitted in response to our proposed action do not 
change our assessment of the 2020 CARB SIP Submittal as described in 
our notice of proposed rulemaking. Therefore, for the reasons discussed 
in detail in the proposed rule and summarized herein, we are finalizing 
our approval of the 2020 CARB SIP Submittal to address the ozone-
related base year emissions inventory requirements for the following 18 
ozone nonattainment areas for the 2015 ozone NAAQS in accordance with 
CAA sections 172(c)(3) and 182(a)(1): Amador County, Butte County, 
Calaveras County, Imperial County, Kern County (Eastern Kern), Los 
Angeles--San Bernardino Counties (West Mojave Desert), Los Angeles--
South Coast Air Basin, Mariposa County, Nevada County (Western part), 
Riverside County (Coachella Valley), Sacramento Metro, San Francisco 
Bay Area, San Joaquin Valley, San Luis Obispo (Eastern part), Sutter 
Buttes, Tuolumne County, Tuscan Buttes, and Ventura County.

IV. Statutory and Executive Order Reviews

    Under the Clean Air Act, the Administrator is required to approve a 
SIP submission that complies with the provisions of the CAA and 
applicable Federal regulations. 42 U.S.C. 7410(k); 40 CFR 52.02(a). 
Thus, in reviewing SIP submissions, the EPA's role is to approve state 
choices, provided that they meet the criteria of the Clean Air Act. 
Accordingly, this action merely approves state law as meeting Federal 
requirements and does not impose additional requirements beyond those 
imposed by state law. For that reason, this action:
     Is not a significant regulatory action subject to review 
by the Office of Management and Budget under Executive Orders 12866 (58 
FR 51735, October 4, 1993) and 13563 (76 FR 3821, January 21, 2011);
     Does not impose an information collection burden under the 
provisions of the Paperwork Reduction Act (44 U.S.C. 3501 et seq.);
     Is certified as not having a significant economic impact 
on a substantial number of small entities under the Regulatory 
Flexibility Act (5 U.S.C. 601 et seq.);
     Does not contain any unfunded mandate or significantly or 
uniquely affect small governments, as described in the Unfunded 
Mandates Reform Act of 1995 (Pub. L. 104-4);
     Does not have federalism implications as specified in 
Executive Order 13132 (64 FR 43255, August 10, 1999);
     Is not an economically significant regulatory action based 
on health or safety risks subject to Executive Order 13045 (62 FR 
19885, April 23, 1997);
     Is not a significant regulatory action subject to 
Executive Order 13211 (66 FR 28355, May 22, 2001); and
     Is not subject to requirements of Section 12(d) of the 
National Technology Transfer and Advancement Act of 1995 (15 U.S.C. 272 
note) because application of those requirements would be inconsistent 
with the Clean Air Act.
    The State did not evaluate environmental justice considerations as 
part of its SIP submittal. There is no information in the record 
inconsistent with the stated goals of Executive Order 12898 (59 FR 
7629, February 16, 1994) of achieving environmental justice for people 
of color, low-income populations, and indigenous peoples.

[[Page 59021]]

    In addition, the SIP is not approved to apply on any Indian 
reservation land or in any other area where the EPA or an Indian tribe 
has demonstrated that a tribe has jurisdiction. In those areas of 
Indian country, the rule does not have tribal implications and will not 
impose substantial direct costs on tribal governments or preempt tribal 
law as specified by Executive Order 13175 (65 FR 67249, November 9, 
2000).
    The Congressional Review Act, 5 U.S.C. 801 et seq., as added by the 
Small Business Regulatory Enforcement Fairness Act of 1996, generally 
provides that before a rule may take effect, the agency promulgating 
the rule must submit a rule report, which includes a copy of the rule, 
to each House of the Congress and to the Comptroller General of the 
United States. The EPA will submit a report containing this action and 
other required information to the U.S. Senate, the U.S. House of 
Representatives, and the Comptroller General of the United States prior 
to publication of the rule in the Federal Register. A major rule cannot 
take effect until 60 days after it is published in the Federal 
Register. This action is not a ``major rule'' as defined by 5 U.S.C. 
804(2).
    Under section 307(b)(1) of the Clean Air Act, petitions for 
judicial review of this action must be filed in the United States Court 
of Appeals for the appropriate circuit by November 28, 2022. Filing a 
petition for reconsideration by the Administrator of this final rule 
does not affect the finality of this action for the purposes of 
judicial review nor does it extend the time within which a petition for 
judicial review may be filed, and shall not postpone the effectiveness 
of such rule or action. This action may not be challenged later in 
proceedings to enforce its requirements. (See section 307(b)(2).)

List of Subjects in 40 CFR Part 52

    Environmental protection, Air pollution control, Incorporation by 
reference, Intergovernmental relations, Ozone, Reporting and 
recordkeeping requirements, Volatile organic compounds.

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

    Dated: September 8, 2022.
Martha Guzman Aceves,
Regional Administrator, Region IX.

    For the reasons stated in the preamble, the EPA amends chapter I, 
title 40 of the Code of Federal Regulations as follows:

PART 52--APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS

0
1. The authority citation for part 52 continues to read as follows:

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

Subpart F--California

0
2. Section 52.220 is amended by adding paragraph (c)(589) to read as 
follows:

Sec.  52.220   Identification of plan--in part.

* * * * *
    (c) * * *
    (589) The following plan was submitted on July 27, 2020 by the 
Governor's designee.
    (i) [Reserved]
    (ii) Additional materials. (A) California Air Resources Board.
    (1) California Air Resources Board, ``70 ppb Ozone SIP Submittal,'' 
excluding section III, ``VMT Offset Demonstration,'' release date: May 
22, 2020.
    (2) [Reserved]
    (B) [Reserved]

[FR Doc. 2022-20586 Filed 9-28-22; 8:45 am]
BILLING CODE 6560-50-P