[Federal Register Volume 83, Number 243 (Wednesday, December 19, 2018)]
[Rules and Regulations]
[Pages 65093-65101]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2018-27477]


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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 52

[EPA-R09-OAR-2017-0177; FRL-9987-97-Region 9]


Approval and Promulgation of Air Quality State Implementation 
Plans; California; Interstate Transport Requirements for Ozone, Fine 
Particulate Matter, and Sulfur Dioxide

AGENCY: Environmental Protection Agency (EPA).

ACTION: Final rule.

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SUMMARY: The Environmental Protection Agency (EPA) is finalizing 
approval of a State Implementation Plan (SIP) submission from the State 
of California regarding certain interstate transport requirements of 
the Clean Air Act (CAA or ``Act''). This submission addresses the 2008 
ozone national ambient air quality standards (NAAQS), the 2006 fine 
particulate matter (PM<INF>2.5</INF>) and 2012 PM<INF>2.5</INF> NAAQS, 
and the 2010 sulfur dioxide (SO<INF>2</INF>) NAAQS. The interstate 
transport requirements under the CAA consist of several elements; this 
final rule pertains only to significant contribution to nonattainment 
and interference with maintenance of the NAAQS in other states.

DATES: This final rule is effective on January 18, 2019.

ADDRESSES: The EPA has established a docket for this action under 
Docket ID No. EPA-R09-OAR-2017-0177. 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.

FOR FURTHER INFORMATION CONTACT: Rory Mays, Air Planning Office (AIR-
2), EPA Region IX, (415) 972-3227, <a href="/cdn-cgi/l/email-protection#086569717b267a677a71486d7869266f677e"><span class="__cf_email__" data-cfemail="9cf1fde5efb2eef3eee5dcf9ecfdb2fbf3ea">[email protected]</span></a>.

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

Table of Contents

I. Proposed Action
    A. Evaluation for the 2008 Ozone NAAQS
    B. Evaluation for the 2006 PM<INF>2.5</INF> and 2012 
PM<INF>2.5</INF> NAAQS
    C. Evaluation for the 2010 SO<INF>2</INF> NAAQS
II. Public Comments and EPA Responses
III. EPA Action
IV. Statutory and Executive Order Reviews

I. Proposed Action

    The California Air Resources Board (CARB) submitted the 
``California Infrastructure State Implementation Plan (SIP) Revision, 
Clean Air Act Section 110(a)(2)(D)'' on January 19, 2016 (``California 
Transport Plan'' or ``Plan'').\1\ This Plan addresses interstate 
transport for the 2008 ozone, 2006 PM<INF>2.5</INF>, 2012 
PM<INF>2.5</INF>, and 2010 SO<INF>2</INF> NAAQS.\2\ On February 7, 
2018, the EPA proposed to approve the California Transport Plan into 
the California SIP because we determined that it complies with the 
relevant CAA requirements.\3\ Our proposed action contains more 
information on the California Transport Plan and our evaluation. We 
summarize the key points of our proposed rulemaking and evaluation in 
this final rule.
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    \1\ Letter dated January 19, 2016, from Richard W. Corey, 
Executive Officer, CARB to Jared Blumenfeld, Regional Administrator, 
Region 9, EPA.
    \2\ The 2008 ozone NAAQS include primary and secondary 8-hour 
ozone NAAQS of 0.075 parts per million (ppm), 73 FR 16436 (March 27, 
2008). The 2006 PM<INF>2.5</INF> NAAQS include primary and secondary 
24-hour NAAQS for PM<INF>2.5</INF> of 35 micrograms per cubic meter 
([micro]g/m\3\), 71 FR 61144 (October 17, 2006). The 2012 
PM<INF>2.5</INF> NAAQS include a primary annual PM<INF>2.5</INF> 
NAAQS of 12.0 [mu]g/m\3\, 78 FR 3086 (January 15, 2013). The 2010 
SO<INF>2</INF> NAAQS include a primary 1-hour SO<INF>2</INF> NAAQS 
of 75 parts per billion (ppb), 75 FR 35520 (June 22, 2010).
    \3\ 83 FR 5375.
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    Sections 110(a)(2)(D)(i)(I)-(II) of the CAA require SIPs to include 
provisions prohibiting any source or other type of emissions activity 
in one state from emitting any air pollutant in amounts that will 
contribute significantly to nonattainment, or interfere with 
maintenance, of the NAAQS, or interfere with measures required to 
prevent significant deterioration of air quality or to protect 
visibility in any other state. This final rule addresses the

[[Page 65094]]

two requirements under section 110(a)(2)(D)(i)(I), which we refer to as 
prong 1 (significant contribution to nonattainment of the NAAQS in any 
other state) and prong 2 (interference with maintenance of the NAAQS in 
any other state).\4\ The EPA refers to SIP revisions addressing the 
requirements of section 110(a)(2)(D)(i)(I) as ``good neighbor SIPs'' or 
``interstate transport SIPs.''
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    \4\ The remaining interstate and international transport 
requirements of CAA section 110(a)(2)(D) for the 2008 ozone, 2006 
PM<INF>2.5</INF>, 2012 PM<INF>2.5</INF>, and 2010 SO<INF>2</INF> 
NAAQS for California have been addressed in prior State submissions 
and EPA rulemakings. 81 FR 18766 (April 1, 2016). Specifically, this 
includes the section 110(a)(2)(D)(i)(II) requirements relating to 
interference with measures required to be included in the applicable 
implementation plan for any other state under part C to prevent 
significant deterioration of air quality (prong 3) or to protect 
visibility (prong 4), and the section 110(a)(2)(D)(ii) requirements 
relating to interstate and international pollution abatement.
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    In addition to our evaluation of the California Transport Plan with 
respect to transport of air pollution to other states, we considered 
transport to the Morongo Band of Mission Indians (``Morongo'') and the 
Pechanga Band of Luise[ntilde]o Indians (``Pechanga''), given their 
regulatory monitoring for certain pollutants and comments during the 
EPA's rulemaking on California's interstate transport SIP for the 1997 
ozone and 1997 PM<INF>2.5</INF> NAAQS. Based on our review of the 
ambient air quality data of Morongo and Pechanga and the emission 
control regimes of the South Coast Air Quality Management District 
(AQMD) for stationary sources and of CARB for mobile sources, as 
described in the EPA's memo to the docket,\5\ the EPA proposed to find 
that California adequately prohibits the emission of air pollutants in 
amounts that will significantly contribute to nonattainment, or 
interfere with maintenance, of the 2008 ozone, 2006 PM<INF>2.5</INF>, 
2012 PM<INF>2.5</INF>, and 2010 SO<INF>2</INF> NAAQS in the Morongo and 
Pechanga reservations. The EPA offered consultation with each tribe at 
the time of the proposal; neither tribe requested such consultation.\6\
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    \5\ Memorandum of January 2018 from Rory Mays, Air Planning 
Office, Air Division, Region IX, EPA, ``Interstate Transport for the 
2008 ozone, 2006 PM<INF>2.5</INF>, 2012 PM<INF>2.5</INF>, and 2010 
SO<INF>2</INF> NAAQS and the Morongo Band of Mission Indians and the 
Pechanga Band of Luise[ntilde]o Indians.''
    \6\ See, e.g., email dated February 27, 2018 from Kelcey 
Stricker, Environmental Director, Pechanga Band of Luise[ntilde]o 
Mission Indians to Rory Mays, Air Planning Office, U.S. EPA Region 
IX, indicating that Pechanga did not see the need to consult. The 
EPA did not receive a request for consultation or a comparable email 
from the Morongo Band of Mission Indians.
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A. Evaluation for the 2008 Ozone NAAQS

    In our proposed rulemaking the EPA agreed with the conclusion of 
the California Transport Plan that California meets the CAA 
requirements for interstate transport prongs 1 and 2 for the 2008 ozone 
NAAQS. However, our rationale differed from that presented by CARB. The 
analysis in the California Transport Plan relies primarily on CARB's 
conclusion that the ozone transport linkages are uncertain and 
therefore no significant contribution or interference with maintenance 
has been demonstrated. The EPA's evaluation finds that the transport 
linkages are adequately quantified (and uncertainties sufficiently 
addressed) and that California's emission control programs adequately 
address the transport requirements.
    The EPA presented the various elements of our evaluation that led 
to this conclusion.\7\ The EPA first explained that it approached its 
evaluation considering the four-step framework for evaluating regional 
ozone transport that has been developed through several prior regional 
EPA rulemakings. This framework evaluates downwind air quality (step 
1), upwind state linkages (step 2), and various cost and air quality 
factors (step 3) to identify whether a state will significantly 
contribute to nonattainment or interfere with maintenance of the NAAQS 
in another state and to implement any necessary emission reductions 
(step 4). We discussed the EPA's modeling for the Cross-State Air 
Pollution Rule (CSAPR) Update rule (``CSAPR Update''),\8\ which 
identified regulatory monitors throughout the continental U.S. that 
were expected to exceed the NAAQS in 2017 based on both projected 
average design values and monitored data as ``nonattainment receptors'' 
(i.e., not expected to attain) and those that may have difficulty 
maintaining the NAAQS, taking into account historic variability in air 
quality, as ``maintenance receptors,'' and estimated the contribution 
of other states to the ozone levels at each of these receptors. The 
analytic year of 2017 was selected since it corresponds to the 
attainment year prior to the mid-2018 attainment deadline for 2008 
ozone NAAQS nonattainment areas classified as Moderate.
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    \7\ For discussion of our general evaluation approach and our 
specific evaluation with respect to the 2008 ozone NAAQS, please see 
sections II.A and II.B of our proposed rulemaking preamble. 83 FR 
5375 (February 7, 2018).
    \8\ 81 FR 74504 (October 26, 2016).
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    We addressed CARB's assertions regarding ozone transport modeling 
uncertainties (relating to a prior, similar iteration of the EPA's 
ozone transport modeling) for identifying nonattainment and maintenance 
receptors in 2017 and linkages from California to downwind receptors, 
and discussed the contrast that CARB draws between ozone transport in 
the eastern versus western U.S.
    Based on our analysis, we proposed to find that California is 
linked to three maintenance receptors in the Denver, Colorado area. 
This conclusion was based on a combination of factors: (1) The EPA's 
projection that California emissions would contribute above 1 percent 
of the 2008 ozone NAAQS at each of the three receptors (1.1 to 2.6 
percent), (2) other states also contribute above 1 percent of the NAAQS 
to these receptors, and (3) the average interstate contribution to 
ozone concentrations from all states upwind of these receptors was both 
considerable (9.2 to 9.4 percent of the projected ozone design values) 
and comparable to collective contributions from upwind states to 
receptors in Texas as evaluated in the CSAPR Update. Accordingly, we 
proposed that a 1 percent threshold is appropriate as an air quality 
threshold to determine whether California is ``linked'' to the three 
maintenance receptors in the Denver area for the 2008 ozone NAAQS.
    Our proposed finding that California is linked to the three Denver 
area receptors prompted further inquiry into whether the contributions 
would interfere with maintenance at the receptors and whether there are 
cost-effective controls that can be employed to reduce emissions. To do 
so, we presented a general assessment of the emission sources in 
California, including mobile and stationary emission sources. We 
proposed to find that control measures in the California SIP for mobile 
sources, large electricity generating units (EGUs), and large non-EGU 
sources (e.g., cement plants and oil refineries), adequately prohibit 
the emission of air pollution in amounts that will interfere with 
maintenance of the 2008 ozone NAAQS at the identified receptors in the 
Denver area.
    We discussed California's mobile source measures, which are 
primarily adopted and implemented by CARB, and stationary source 
measures, which are primarily adopted and implemented by California's 
35 local air districts. For the latter, beyond the measures described 
in the California Transport Plan, we also considered stationary

[[Page 65095]]

source control measures for EGUs, consistent with the controls analysis 
for the CSAPR and CSAPR Update rulemakings,\9\ and examples of 
stationary source control measures for the largest non-EGU sources in 
the State.
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    \9\ 76 FR 48208 (August 8, 2011) and 81 FR 74504 (October 26, 
2016), respectively.
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    We noted that California mobile sources account for approximately 
70 percent of the projected 2017 nitrogen oxide (NO<INF>X</INF>) 
emissions and that CARB has established a comprehensive program to 
control and reduce mobile source emissions within the state. The EPA 
has approved many of CARB's mobile source regulations as part of the 
California SIP, including regulations establishing standards and other 
requirements relating to emissions from cars, light- and medium-duty 
trucks, heavy-duty trucks, commercial harbor craft, mobile cargo 
handling equipment, marine engines and boats, and off-highway 
recreational vehicles. To support and enhance these emissions 
standards, we also noted that CARB has established specific gasoline 
and diesel fuel requirements, and the California Bureau of Automotive 
Repair has established a vehicle emissions and inspection (i.e., ``smog 
check'') program.
    With respect to stationary and area emission sources, we noted that 
the California SIP has hundreds of rules that limit the emissions of 
NO<INF>X</INF> and volatile organic compounds (VOCs) and that many of 
these rules were developed by local air districts to reduce ozone 
concentrations in response to the prior 1979 1-hour ozone and 1997 8-
hour ozone NAAQS.
    For EGUs producing greater than 25 megawatts of electricity, 
including non-fossil fuel EGUs, we described how California's statewide 
NO<INF>X</INF> emissions rate is very low (0.0097 pounds of 
NO<INF>X</INF> per million British thermal units in 2018) and ranks as 
the 47th lowest out of the 48 contiguous states and Washington, DC for 
which the EPA performed power sector modeling in the context of the 
CSAPR Update. We found that California produces electricity very 
efficiently in terms of NO<INF>X</INF> emissions and is therefore 
unlikely to have significant, further NO<INF>X</INF> reductions 
available from the EGU sector at reasonable cost.
    In investigating the potential for further NO<INF>X</INF> emissions 
reductions from EGUs, we found that additional NO<INF>X</INF> 
reductions from EGUs in California would cost more than three times the 
amount that the EPA determined to be cost-effective to partially 
address ozone transport obligations in the eastern U.S. under the CSAPR 
Update (i.e., reductions expected above $5,000 per ton of 
NO<INF>X</INF> in California versus a cost-effective control level of 
$1,400 per ton in the CSAPR Update rulemaking for 22 eastern states). 
Further, we noted that the largest collection of EGU facilities 
emitting over 100 tons per year (tpy) of NO<INF>X</INF>, per the 2011 
National Emissions Inventory, are found in the San Joaquin Valley, Bay 
Area, and South Coast air districts and are subject to district rules 
that limit NO<INF>X</INF> emissions and have been approved into the 
California SIP.
    For non-EGU stationary sources, we found that they emitted 6.7 
times more NO<INF>X</INF> than EGUs in California in 2011. Of these 
sources, 19 emitted over 500 tpy of NO<INF>X</INF>, including Portland 
cement plants, petroleum refineries, and several other source types, 
and accounted for two thirds of the NO<INF>X</INF> emissions from 
California stationary sources that emitted over 100 tpy in 2011 and 5.2 
percent of the total 2011 NO<INF>X</INF> inventory for California. 
These 19 sources are in the Bay Area, Kern County, Mojave Desert, San 
Joaquin Valley, and South Coast air districts and, overall, are subject 
to rules that limit NO<INF>X</INF> emissions and have been approved 
into the California SIP. For the small number of large non-EGU sources 
that are either subject to NO<INF>X</INF> control measures that have 
not been submitted for approval into the California SIP, or fall 
outside the geographic jurisdiction of the applicable district rules, 
we found that further emission controls would be unlikely to reduce any 
potential impact on downwind states' air quality because such sources 
comprise no more than 0.8 percent of the total NO<INF>X</INF> emitted 
in California in 2011.
    In sum, on the strength of CARB and the local air districts' 
emission control programs, especially for mobile and stationary sources 
of NO<INF>X</INF>, we proposed that the California SIP adequately 
prohibits the emission of air pollutants in amounts that will 
significantly contribute to nonattainment, or interfere with 
maintenance, of the 2008 ozone NAAQS in any other state. The EPA also 
noted that recent modeling shows that by the 2023 ozone season the 
receptors identified in Denver are projected to be ``clean,'' i.e., 
both the average and maximum design values are projected to be below 
the level of the 2008 ozone NAAQS.\10\
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    \10\ Memorandum dated October 27, 2017 from Stephen D. Page, 
Director, EPA Office of Air Quality Planning and Standards, to 
Regional Air Division Directors, Regions 1-10. Available at: https://www.epa.gov/sites/production/files/2017-10/documents/final_2008_o3_naaqs_transport_memo_10-27-17b.pdf.
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B. Evaluation for the 2006 PM2.5 and 2012 PM2.5 NAAQS

    The EPA proposed to approve the California Transport Plan for the 
CAA requirements for interstate transport prongs 1 and 2 for the 2006 
PM<INF>2.5</INF> and 2012 PM<INF>2.5</INF> NAAQS. First, we discussed 
our evaluation of CARB's identification of nonattainment and 
maintenance receptors in western states based on data presented in the 
California Transport Plan as well as the EPA's analysis of 2009-2013 
24-hour and annual PM<INF>2.5</INF> design values. Based on that 
evaluation, we presented modified lists of such receptors that largely 
follow the lists of receptors in the California Transport Plan.
    For the 2006 24-hour PM<INF>2.5</INF> NAAQS, we derived a list of 
18 potential nonattainment receptors and three potential maintenance 
receptors within 11 western states (excluding California) \11\ that 
accounted for the information presented in the California Transport 
Plan and ambient air quality and emissions data that were common to our 
evaluation of both the 24-hour and annual NAAQS. We also presented the 
24-hour PM<INF>2.5</INF> design values for 2014-2016 at each identified 
receptor.
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    \11\ For purposes of this rulemaking, ``western states'' refers 
to the states of Arizona, California, Colorado, Idaho, Montana, 
Nevada, New Mexico, Oregon, Utah, Washington, and Wyoming.
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    For the 2012 annual PM<INF>2.5</INF> NAAQS, we did not find that 
there would be any potential nonattainment receptors and we identified 
two potential maintenance receptors, one in Idaho and one in 
Pennsylvania. To do so, we relied on photochemical modeling results 
presented in the EPA's informational memo on interstate transport for 
the 2012 PM<INF>2.5</INF> NAAQS (``2012 PM<INF>2.5</INF> NAAQS 
Transport Memo''), which projected annual PM<INF>2.5</INF> design 
values for 2017 and 2025 at each regulatory PM<INF>2.5</INF> monitor in 
the continental U.S.\12\ We used those results to evaluate projected 
air quality in 2021, which corresponds to the attainment deadline for 
2012 PM<INF>2.5</INF> NAAQS nonattainment areas classified as Moderate. 
We also addressed some differences in the receptors identified by CARB 
and those identified by the EPA and considered the annual 
PM<INF>2.5</INF> design values for 2014-2016 at the potential 
maintenance receptors identified in the EPA's 2012 PM<INF>2.5</INF> 
NAAQS Transport Memo.
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    \12\ 2012 PM<INF>2.5</INF> NAAQS Transport Memo, Table 1, 5. 
Available at https://www.epa.gov/pm-pollution/information-interstate-transport-good-neighbor-provision-2012-fine-particulate-matter.
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    We then discussed California emissions of PM<INF>2.5</INF> and its 
precursors, California's regulations to limit such emissions, and the 
emissions trends

[[Page 65096]]

resulting from such regulations. We discussed California's control 
measures before our more specific discussion of interstate transport 
prongs 1 and 2 for each NAAQS because such discussion provided a common 
basis for evaluating the California emissions component of CARB's 
weight of evidence analysis. For three PM<INF>2.5</INF> precursors 
pollutants, we incorporated our evaluation of California's emissions 
and regulatory programs for NO<INF>X</INF> and VOC (for the 2008 ozone 
NAAQS) and oxides of sulfur (SO<INF>X</INF>) (for the 2010 
SO<INF>2</INF> NAAQS).\13\ For directly-emitted PM<INF>2.5</INF>, we 
affirmed that many of California's measures limit the emission of 
particulate matter and have been approved into the California SIP. 
These include the State's mobile source emission standards and test 
procedures for heavy-duty engines and vehicles, passenger cars, light 
duty trucks, and medium duty vehicles; in-use diesel standards for 
heavy-duty trucks, buses, drayage trucks, and off-road vehicles; and 
inspection and maintenance programs, as well as air district stationary 
source measures for combustion sources of PM<INF>2.5</INF>, such as 
open burning, refineries, and cement plants, and dust sources of 
PM<INF>2.5</INF>, such as fugitive dust from roads and agricultural 
operations.
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    \13\ CARB estimates that SO<INF>2</INF> comprises 97% of the 
state-wide SO<INF>X</INF> inventory and therefore used California 
SO<INF>X</INF> emissions in its analysis to represent California 
SO<INF>2</INF> emissions. California Transport Plan, App. C, C-1.
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    We also described trends in California emissions, which have 
decreased by substantial amounts (e.g., statewide decreases from 2000 
to 2016 of 75 percent direct PM<INF>2.5</INF>, 66 percent 
NO<INF>X</INF>, 54 percent VOC, and 75 percent SO<INF>2</INF>) in 
response to state and local control measures, as well as federal 
measures for sources outside California's regulatory authority.
    Based on our review of the state and local measures cited in the 
California Transport Plan that limit the emission of PM<INF>2.5</INF> 
and its precursor pollutants and of the applicable California emission 
trends, which are generally decreasing, we agreed with CARB's general 
conclusions regarding interstate transport of PM<INF>2.5</INF>: That 
California emissions from stationary sources are subject to stringent 
limits for direct PM<INF>2.5</INF> and its precursors (e.g., 
NO<INF>X</INF> and SO<INF>X</INF>); that California has a long history 
of reducing emissions through motor vehicle and fuel standards; and 
that state and local measures will continue to reduce the potential for 
California emissions to contribute significantly to nonattainment, or 
interfere with maintenance, of the 2006 24-hour PM<INF>2.5</INF> or 
2012 annual PM<INF>2.5</INF> NAAQS in any other state.
    Building on the identification of potential nonattainment and 
maintenance receptors and our discussion of California emissions, we 
presented the EPA's weight of evidence analysis to address the CAA 
requirements, which affirmed CARB's weight of evidence analysis for the 
2006 24-hour PM<INF>2.5</INF> and 2012 annual PM<INF>2.5</INF> NAAQS. 
We prepared a Technical Support Document (TSD) containing our more 
detailed analysis of interstate transport for the 2006 24-hour 
PM<INF>2.5</INF> NAAQS (``EPA's PM<INF>2.5</INF> Transport TSD''), 
which was also relevant for our evaluation of the 2012 annual 
PM<INF>2.5</INF> NAAQS.\14\
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    \14\ ``EPA Evaluation of the California Interstate Transport 
Plan (2006 PM<INF>2.5</INF> NAAQS), Technical Support Document,'' 
EPA, Region IX, January 2018.
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    For interstate transport prongs 1 and 2 for the 2006 24-hour 
PM<INF>2.5</INF> NAAQS, we summarized our evaluation of the areas 
encompassing the 18 nonattainment receptors, grouping them into three 
geographic bins (i.e., Arizona, the Northern Rocky Mountains, and Utah) 
based on the nature of the emission sources affecting the receptors, 
and the areas encompassing the three maintenance receptors, grouping 
them by the two relevant states (Montana and Utah).
    For each receptor area we described our review of the information 
compiled and presented in the California Transport Plan, including 
distance of relevant receptors from California; intervening terrain; 
potential wildfire effects; chemical speciation data; local topography; 
the effect of local emission sources, particularly residential wood 
burning and, in certain cases, other sources (e.g., mobile sources, 
agricultural activities), on wintertime exceedances; and regional 
background levels represented by ambient 24-hour PM<INF>2.5</INF> data 
from Interagency Monitoring of Protected Visual Environments (IMPROVE) 
monitoring sites. We reviewed California's emissions and emission 
control programs for PM<INF>2.5</INF> and its precursors, especially 
for NO<INF>X</INF> and SO<INF>X</INF>, and concluded that California 
has an extensive and effective program for limiting emissions of such 
pollutants. Thus, we proposed that California will not significantly 
contribute to nonattainment or interfere with maintenance of the 2006 
24-hour PM<INF>2.5</INF> NAAQS in any western state.
    As the California Transport Plan did not evaluate PM<INF>2.5</INF> 
transport to states farther east than Montana, Wyoming, Colorado, and 
New Mexico, we evaluated the potential for transport of 
PM<INF>2.5</INF> and its precursors to states farther east. We did so 
by reviewing modeling data from the CSAPR and recent air quality data 
to identify the westernmost area in the East \15\ with potential 
nonattainment or maintenance receptors, and then comparing California's 
likely contributions with the contributions of intervening states that 
may significantly contribute to nonattainment or interfere with 
maintenance of the NAAQS at the potential nonattainment and maintenance 
receptors, respectively.
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    \15\ For purposes of the PM<INF>2.5</INF> evaluation in this 
notice, ``the East'' refers to the 37 states and Washington, DC that 
lie east of the states of Montana, Wyoming, Colorado, and New 
Mexico. The EPA modeled the contribution of states within the East 
to each receptor for CSAPR but did not model the contribution of any 
state further west, such as California.
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    We concluded that California emission sources will not 
significantly contribute to nonattainment or interfere with maintenance 
of the 2006 PM<INF>2.5</INF> NAAQS at the westernmost nonattainment and 
maintenance receptors in the East, which were in Madison County, 
Illinois. This was based on the generally improved air quality in the 
East since the EPA's analysis in 2011 for CSAPR, which reduced the 
number of potential nonattainment or maintenance receptors; the 
distance of the Madison County, Illinois receptors from California; 
intervening terrain; our analysis of the westernmost states linked to 
the Madison receptors and comparison of California emissions; the large 
reductions in emissions of PM<INF>2.5</INF> and its precursors in 
California; and the trend of decreasing 24-hour PM<INF>2.5</INF> 
concentrations at the Madison receptors. As the distance from 
California to the other potential eastern nonattainment or maintenance 
receptors is even greater, we noted that the expected contribution from 
California to 24-hour PM<INF>2.5</INF> concentrations at such receptors 
would be even smaller and thus not significantly contribute to 
nonattainment or interfere with maintenance of the 2006 24-hour 
PM<INF>2.5</INF> NAAQS in any state farther east than Montana, Wyoming, 
Colorado, and New Mexico.
    For interstate transport prongs 1 and 2 for the 2012 annual 
PM<INF>2.5</INF> NAAQS, we agreed with CARB that California will not 
significantly contribute to nonattainment, or interfere with 
maintenance, of the 2012 annual PM<INF>2.5</INF> NAAQS in any other 
state and presented our analysis for potential maintenance receptors in 
Lemhi and Shoshone counties, Idaho and Allegheny County, Pennsylvania.

[[Page 65097]]

    For the potential maintenance receptors in Idaho, we reviewed the 
information compiled and presented in the California Transport Plan, 
including distance of these monitors from California; intervening 
terrain; wildfire effects; local topography; the effect of local 
emission sources on wintertime exceedances of the 24-hour NAAQS and the 
effect of those exceedances on annual PM<INF>2.5</INF> concentrations; 
and rural background levels represented by IMPROVE data. We reviewed 
California's emissions and emission control programs for 
PM<INF>2.5</INF> and its precursors, especially for NO<INF>X</INF> and 
SO<INF>X</INF>, and concluded that California has an extensive and 
effective program for limiting emissions of such pollutants. Thus, we 
proposed that California will not significantly contribute to 
nonattainment or interfere with maintenance of the 2012 annual 
PM<INF>2.5</INF> NAAQS in Idaho or any western state.
    For the potential maintenance receptor in Allegheny County, 
Pennsylvania, we concluded that California emission sources will not 
interfere with maintenance of the 2012 annual PM<INF>2.5</INF> NAAQS. 
This was based on our interpolated projection that the Allegheny 
monitor will likely be attaining the annual PM<INF>2.5</INF> NAAQS in 
2021; the distance of this receptor from California; intervening 
terrain; the contribution modeling performed for CSAPR; the large 
reductions in emissions of PM<INF>2.5</INF> and its precursors in 
California; and the general trend of decreasing annual PM<INF>2.5</INF> 
concentrations at the Allegheny receptor.
    Based on our analysis that there are no nonattainment receptors 
outside of California for the 2012 PM<INF>2.5</INF> NAAQS, and our 
analysis for the maintenance receptors in Idaho and Pennsylvania, we 
proposed that California will not significantly contribute to 
nonattainment, or interfere with maintenance, of the 2012 
PM<INF>2.5</INF> NAAQS in any other state.

C. Evaluation for the 2010 SO2 NAAQS

    The EPA proposed to approve the California Transport Plan for the 
CAA requirements for interstate transport prongs 1 and 2 for the 2010 
SO<INF>2</INF> NAAQS. We described how our evaluation of SO<INF>2</INF> 
transport required a slightly different approach than our evaluation 
for regional pollutants, such as ozone and PM<INF>2.5</INF>, and more 
localized pollutants, like lead, given the universe of SO<INF>2</INF> 
emission sources and physical properties of SO<INF>2</INF> in the 
atmosphere relative to those other pollutants. In our evaluation we 
addressed the air quality, emission sources, and emission trends in the 
states bordering California, i.e., Arizona, Nevada, and Oregon. Then we 
discussed California's air quality, emissions sources, control 
measures, and emission trends with respect to interstate transport 
prong 1, followed by discussion of additional California air quality 
trends and emission trends with respect to interstate transport prong 
2.
    We found that monitored 1-hour SO<INF>2</INF> levels in Arizona, 
Nevada, and Oregon are generally well below 75 ppb; that sources in 
these bordering states that emit over 2,000 tpy of SO<INF>2</INF> are 
located at a distance well beyond a 50-km buffer from California's 
borders where emissions from California sources might be expected to 
have downwind impacts on air quality; and that the downward 
SO<INF>2</INF> emission trends in each bordering state reduce the 
likelihood of SO<INF>2</INF> nonattainment or maintenance issues 
appearing in the future.\16\
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    \16\ This final approval of the California Transport Plan for 
the 2010 SO<INF>2</INF> NAAQS under CAA section 110(a)(2)(D)(i)(I) 
is based on the information contained in the administrative record 
for this action and does not prejudge any other future EPA action 
that may make other determinations regarding California's air 
quality status. Any such future actions, such as area designations 
under any NAAQS, will be based on their own administrative records 
and the EPA's analyses of information that becomes available at 
those times. Future available information may include, and is not 
limited to, monitoring data and modeling analyses conducted pursuant 
to the EPA's SO<INF>2</INF> Data Requirements Rule (80 FR 51052, 
August 21, 2015) and information submitted to the EPA by states, air 
agencies, and third-party stakeholders such as citizen groups and 
industry representatives.
---------------------------------------------------------------------------

    For interstate transport prong 1, the EPA reviewed the analysis 
presented in the California Transport Plan and considered additional 
information on ambient SO<INF>2</INF> monitoring data, SO<INF>2</INF> 
emission sources and controls, including state measures for mobile 
sources and air district measures for large stationary sources, and 
emission trends in California. As for Arizona, Nevada, and Oregon, 
monitored 1-hour SO<INF>2</INF> levels in California are low (most 
often below half the level of the 2010 SO<INF>2</INF> NAAQS); the 29 
SO<INF>2</INF> sources in California that emit over 100 tpy of 
SO<INF>2</INF> are located at a distance well beyond 50 km from 
California's borders, the distance where emissions from California 
sources might be expected to have downwind impacts on air quality in 
bordering states; and California's decreasing SO<INF>2</INF> emission 
trend each reduce the likelihood of California emitting SO<INF>2</INF> 
in amounts that would adversely affect other states in the future.
    Therefore, based on our analysis of SO<INF>2</INF> air quality and 
emission sources in Arizona, Nevada, and Oregon and our analysis of 
SO<INF>2</INF> air quality and emissions in California, we proposed 
that California will not significantly contribute to nonattainment of 
the 2010 SO<INF>2</INF> NAAQS in any other state, per the requirements 
of CAA section 110(a)(2)(D)(i)(I).
    For interstate transport prong 2, the EPA reviewed the analysis 
presented in the California Transport Plan and considered additional 
information on California air quality trends and emission trends to 
evaluate CARB's conclusion that California does not interfere with 
maintenance of the 2010 SO<INF>2</INF> NAAQS in other states. The EPA's 
analysis built on our evaluation of air quality and SO<INF>2</INF> 
emission sources in Arizona, Nevada, and Oregon, and our evaluation for 
significant contribution to nonattainment (prong 1) based on the 
evidence that we reviewed (i.e., low ambient concentrations of 
SO<INF>2</INF>, large distance of SO<INF>2</INF> sources from the 
California border, decreasing SO<INF>2</INF> emissions, and the 
existence of SIP-approved California control measures).
    We found that from 2000 to 2015 both ambient SO<INF>2</INF> 
concentrations and SO<INF>2</INF> emissions from California's largest 
stationary sources have decreased substantially; and that state and 
local measures to limit the sulfur content of fuels and limit 
SO<INF>2</INF> emissions will continue to limit SO<INF>2</INF> 
emissions that might adversely affect other states. Accordingly, we 
proposed that California SO<INF>2</INF> emission sources will not 
interfere with maintenance of the 2010 SO<INF>2</INF> NAAQS in any 
other state, per the requirements of CAA section 110(a)(2)(D)(i)(I).

II. Public Comments and EPA Responses

    The 30-day comment period for the EPA's proposed rulemaking closed 
on March 9, 2018. We received four comment letters in response to the 
proposed rulemaking. CARB submitted a letter affirming its support for 
the EPA's proposed approval.\17\ The Center for Biological Diversity 
(CBD) submitted adverse comments regarding the State's and the EPA's 
evaluation of interstate transport for the 2008 ozone NAAQS.\18\ The 
two remaining letters were anonymous comment letters that raised issues 
outside the scope of this rulemaking and did not identify any material 
issues necessitating a

[[Page 65098]]

response.\19\ The comment letters are available in the docket for this 
rulemaking.
---------------------------------------------------------------------------

    \17\ Letter dated March 9, 2018, from Kurt Karperos, Deputy 
Executive Officer, CARB to Alexis Strauss, Acting Regional 
Administrator, EPA Region IX.
    \18\ Letter dated March 9, 2018, from Robert Ukeiley, Senior 
Attorney, Center for Biological Diversity to Rory Mays, Air Planning 
Office, EPA Region IX.
    \19\ Comments received on February 21, 2018 and February 27, 
2018.
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    CBD requests that the EPA disapprove the California Transport Plan 
with respect to the 2008 ozone NAAQS. We address CBD's comments in 
three parts as follows.
    Comment #1: The commenter states that the ozone transport analysis 
in the California Transport Plan is flawed because it underestimates 
NO<INF>X</INF> emissions from agricultural soils in California. The 
commenter relies on a recent study that concludes that agricultural 
soils are a dominant source of California's NO<INF>X</INF> emissions 
(``Soil NO<INF>X</INF> Study''), especially in the San Joaquin 
Valley.\20\ Based on this study, the commenter states that California's 
NO<INF>X</INF> emissions would have been 20 to 51 percent higher and 
that, by underestimating such emissions, the California Transport Plan 
underestimated California's contribution to downwind states. The 
commenter recommends re-running ozone transport modeling with a 
corrected NO<INF>X</INF> emission inventory for California and suggests 
that this could change the linkages between California and other states 
for ozone. The commenter asserts that, pursuant to the Supreme Court's 
holding in Motor Vehicle Manufacturers Association v. State Farm Mutual 
Automobile Insurance, it is unlawful to fail to consider an important 
aspect of a problem before the agency.\21\
---------------------------------------------------------------------------

    \20\ Almaraz, et al., ``Agriculture is a major source of 
NO<INF>X</INF> pollution in California,'' Science Advances, January 
31, 2018, 1. As this article is copyrighted, it is available in hard 
copy, but not available electronically at Regulations.gov, as part 
of the docket of this rulemaking; see the ADDRESSES section of this 
action for hard copy viewing information. It is also publicly 
available at: http://advances.sciencemag.org/content/4/1/eaao3477/tab-pdf.
    \21\ 463 U.S. 29, 43 (1983).
---------------------------------------------------------------------------

    Response #1: The EPA disagrees that the California Transport Plan 
is flawed in this manner and that the EPA failed to consider an 
important aspect of interstate transport for the 2008 ozone NAAQS. As 
an initial matter, the CSAPR Update modeling estimates that California 
contributes more than 1 percent of the NAAQS to downwind maintenance 
receptors in Denver (i.e., California is ``linked'' to receptors in 
Denver). An increase in NO<INF>X</INF> emissions from California could 
potentially increase the magnitude of the contribution to these 
receptors but would be unlikely to result in any additional downwind 
linkages for California because there are no other nonattainment or 
maintenance receptors in the West (excluding California), based on 
EPA's CSAPR Update modeling. Moreover, in the CSAPR Update four-step 
process, the amount of contribution above the 1 percent threshold is 
not a factor in determining whether the upwind state's contribution is 
significant or will interfere with maintenance.\22\
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    \22\ The 1 percent threshold can serve to limit the scope of an 
upwind state's emission reduction obligation if upwind emission 
reductions would otherwise reduce a state's impact to below the 
threshold. See EME Homer City Generation, L.P. v. EPA, 134 S. Ct. 
1584, 1608-09 (2014) (the EPA cannot require a state to reduce its 
contribution to every receptor to which it is linked to below 1 
percent of the NAAQS). In this action, however, the EPA has not 
concluded that California's impact to any downwind receptors would 
be reduced below the 1 percent threshold as a result of the emission 
controls implemented by the State's SIP. Therefore, the potential 
additional impact of NO<INF>X</INF> emissions resulting from 
agricultural soils would not implicate this limit on the Agency's 
statutory authority.
---------------------------------------------------------------------------

    Although the study upon which the commenter relies was not 
published until after the EPA's proposed rulemaking was signed on 
January 26, 2018, we have considered the commenter's statement and the 
study on possible underestimation of NO<INF>X</INF> emissions from 
agricultural soils in California and potential effects in analyzing 
California's contribution to ozone in downwind states. Accordingly, we 
present a brief synopsis of how the CSAPR Update modeling accounted for 
NO<INF>X</INF> emissions from land in California, as well as a summary 
of the Soil NO<INF>X</INF> Study referenced by the commenter and our 
evaluation thereof with respect to this rulemaking.
    In 2016, the EPA's CSAPR Update modeling used NO<INF>X</INF> 
emissions from soils for the continental U.S based on application of 
the Biogenic Emissions Inventory System (BEIS version 3.61).\23\ 
Emissions of soil NO<INF>X</INF> vary by land cover type and, 
accordingly, model emission factors vary for each type of land cover. 
For example, the emission factor for agricultural lands is relatively 
higher than grasslands due to application of nitrogen-based 
fertilizers. The annual soil NO<INF>X</INF> emissions from California 
were estimated to be 30,593 tpy in both 2011 and 2017, which 
corresponds to 4.1 percent of the total 2011 NO<INF>X</INF> inventory 
for California (740,179 tpy) and 5.6 percent of the total 2017 base 
case NO<INF>X</INF> inventory (544,972 tpy), respectively. Thus, the 
CSAPR Update modeling accounted for the effect of California's soil 
NO<INF>X</INF> emissions on ozone formation and downwind transport to 
other states.
---------------------------------------------------------------------------

    \23\ Information on BEIS can be found at https://www.epa.gov/air-emissions-modeling/biogenic-emission-inventory-system-beis. This 
web page includes a brief version history of BEIS, including points 
at which the system's soil NO algorithm was revised based on the 
work of peer-reviewed research papers, and a list of BEIS references 
at https://www.epa.gov/sites/production/files/2015-10/documents/beis_references.pdf. The EPA's emissions modeling platform TSD for 
the CSAPR Update final rule describes how BEIS was used to estimate 
emissions from soils and vegetation. ``Technical Support Document 
(TSD) Preparation of Emission Inventories for the Version 6.3, 2011 
Emissions Modeling Platform,'' EPA, August 2016, 33-35.
---------------------------------------------------------------------------

    In the Soil NO<INF>X</INF> Study, the authors generated annual 
estimates of soil NO<INF>X</INF> emissions from California using a 
nitrogen isotope model and the Integrated Model for the Assessment of 
the Global Environment at a 4 kilometer (km) by 4 km resolution. These 
complex biogeochemical models include the full suite of variables 
thought to contribute to soil NO<INF>X</INF> emissions. The model 
results were compared to a limited number of observations from surface 
measurements around California. The average modeled NO<INF>X</INF> 
emissions were comparable to the surface measurements in some areas and 
larger than the surface measurements in other areas.\24\
---------------------------------------------------------------------------

    \24\ Soil NO<INF>X</INF> Study, Table 1, 3.
---------------------------------------------------------------------------

    The authors then compared model predicted emissions to CARB's non-
soil NO<INF>X</INF> emissions inventory and estimated that soil 
NO<INF>X</INF> emissions account for 25 percent of California's total 
NO<INF>X</INF> emissions.\25\ They note that this is in the range of 
previous modeling studies that considered agricultural soils worldwide. 
With respect to the San Joaquin Valley, the study also used airborne 
and surface measurements of NO<INF>X</INF> from a separate study \26\ 
to estimate total NO<INF>X</INF> emissions from a portion of the San 
Joaquin Valley of 190 metric tons of nitrogen per day (tnpd), with a 
range of plus or minus 130 tnpd.
---------------------------------------------------------------------------

    \25\ The Soil NO<INF>X</INF> Study notes that CARB ascribes 
about 3.8 percent of California's total NO<INF>X</INF> emissions to 
cropland soils. Soil NO<INF>X</INF> Study, p. 1. The commenters did 
not attempt to further compare the model results of the Soil 
NO<INF>X</INF> Study with the emissions inventory used in the 
California Transport Plan (based on the initial CSAPR Update 
modeling) nor the CSAPR Update modeling, upon which the EPA's 
proposed rulemaking was based. Notwithstanding, the proportion of 
CARB's cropland NO<INF>X</INF> emissions estimates appear to fall in 
a similar scale to those modeled for the EPA's CSAPR Update rule.
    \26\ Trousdell, et al., ``Observing entrainment mixing, 
photochemical ozone production, and regional methane emissions by 
aircraft using a simple mixed-layer framework,'' Atmospheric 
Chemistry and Physics. 16, 15433-15450 (2016).
---------------------------------------------------------------------------

    The Soil NO<INF>X</INF> Study concludes that it is the first study 
to include a spatially explicit estimate of soil NO<INF>X</INF> 
emissions compared to other emission sources in California. While 
acknowledging the uncertainty in the estimate, the Soil NO<INF>X</INF> 
Study further concludes that its model results add to a growing body of

[[Page 65099]]

literature suggesting that soil NO<INF>X</INF> emissions could be 
significantly underestimated in current inventories and possibly 
increase California's total NO<INF>X</INF> emissions by 20 to 51 
percent.\27\
---------------------------------------------------------------------------

    \27\ Id. at 1.
---------------------------------------------------------------------------

    The EPA acknowledges the value that studies of this kind contribute 
towards a better understanding of soil NO<INF>X</INF> emissions from 
California. However, the quantification of such emissions is currently 
uncertain, as described below, and would require further field research 
to substantiate. The commenters did not address the uncertainties 
expressed in the study and did not consider other important analytical 
aspects of interstate transport of ozone.
    First, the study acknowledges that a limited number of surface 
measurements were available for purposes of comparing the model results 
and, where observations exist, there is a large range in observed 
values due to varying soil conditions (e.g., relating to temperature, 
moisture, fertilizer application, etc.). The authors acknowledge the 
difficulty in comparing the model results to the observations and note 
the need for more field measurements.\28\ Second, there was a 
significant degree of uncertainty in the aircraft estimates of 
NO<INF>X</INF> emissions over the San Joaquin Valley (190 tnpd plus or 
minus 130 tnpd, which equates to plus or minus 68 percent). Further 
research would be needed to determine whether these higher levels of 
soil NO<INF>X</INF> emissions over California and elsewhere are 
accurate and reliable before updates are included in air quality 
modeling to support regulatory decisions.\29\
---------------------------------------------------------------------------

    \28\ Id. at 5.
    \29\ Technical comments have been published in response to the 
Soil NO<INF>X</INF> Study that present additional uncertainties 
(with respect to the calculations used) in the Soil NO<INF>X</INF> 
Study and recommend supplemental data that could be released to 
allow for an improved assessment of the study. Maaz, et al., 
``Inconsistencies undermine the conclusion that agriculture is a 
dominant source of NO<INF>X</INF> in California,'' Science Advances, 
September 12, 2018. As these technical comments are copyrighted, 
they are available in hard copy as part of the docket of this 
rulemaking; see the ADDRESSES section of this action for viewing 
information. They are also publicly available at: http://advances.sciencemag.org/content/4/9/eaat4706?intcmp=trendmd-adv.
---------------------------------------------------------------------------

    Furthermore, in the EPA's proposed rulemaking, we described the 
rationale for our disagreement with CARB's assertions in the California 
Transport Plan that California's contributions to ozone levels in the 
Denver area were overestimated, while acknowledging that the future 
research that CARB suggests to better characterize ozone transport from 
California to other states could prove valuable.\30\ In this response, 
we disagree with the commenter that California's contributions to such 
ozone levels were underestimated, while similarly acknowledging the 
value of further research to better characterize California's 
NO<INF>X</INF> emissions. In both cases, however, we assert that the 
prospect of future research that might better quantify California's 
emissions or their effect on other states' ozone levels does not itself 
undermine the technical adequacy of the EPA's current modeling for the 
2008 ozone NAAQS. We reaffirm that the CSAPR Update modeling, including 
its emissions inventory bases, and our analysis with respect to 
California based on that modeling adequately estimate the interstate 
transport of ozone from California to downwind states.
---------------------------------------------------------------------------

    \30\ 83 FR 5375, 5380 (February 7, 2018).
---------------------------------------------------------------------------

    In sum, the soil NO<INF>X</INF> emissions used in the CSAPR Update 
modeling, upon which our evaluation of the California Transport Plan 
relies for the 2008 ozone NAAQS, were based on the BEIS, which 
incorporates prior research on soil NO<INF>X</INF> as noted above. 
While the Soil NO<INF>X</INF> Study suggests that California's soil 
NO<INF>X</INF> emissions may be underestimated, they have not been 
adequately quantified and verified to a sufficient degree to replace 
the emissions inventories that were part of the analytical basis of the 
EPA's proposal to approve California Transport Plan for the 2008 ozone 
NAAQS, nor to warrant re-running the ozone transport modeling. 
Furthermore, the CSAPR modeling and our proposed finding did indicate 
that California is linked to downwind receptors, and therefore we 
presented a general assessment of cost-effective controls that can be 
employed to reduce emissions from sources in California.
    The EPA therefore disagrees that it has failed to consider an 
important aspect of the interstate transport problem in violation of 
the Supreme Court's holding in State Farm. We affirm that the EPA has 
considered the multiple important aspects of interstate transport of 
ozone from California to other states, as described in our proposed 
rulemaking and in this final rule's response to comments. These aspects 
include, but are not limited to, consideration of measured and modeled 
ambient ozone concentrations, measured and estimated NO<INF>X</INF> and 
VOC emissions inventories for California and the continental U.S., 
application of state of the science modeling tools for regional air 
pollution analysis and appropriate model validation, existing and 
planned emission control regimes, and meteorology. Furthermore, we have 
considered the commenter's arguments with respect to California's soil 
NO<INF>X</INF> emissions and disagree that the science of such 
emissions is quantified and verified to a sufficient degree to warrant 
a new analysis of interstate transport from California to other states 
for the 2008 ozone NAAQS.
    Comment #2: The commenter states that the ozone transport analysis 
in the California Transport Plan is flawed by failing to consider 
whether soil NO<INF>X</INF> emissions from California are adequately 
controlled. Specifically, the commenter states that the EPA failed to 
consider whether California has rules to limit NO<INF>X</INF> via 
agricultural management practices, whether such rules are in the 
California SIP, and whether such rules are adequate. The commenter does 
not believe that such rules are in place.
    Response #2: We disagree with the commenter's assertion that the 
California Transport Plan should have examined whether soil 
NO<INF>X</INF> emissions are subject to control and whether such 
controls are adequate for purposes of the interstate transport 
requirements for the 2008 ozone NAAQS. This flows from our 
considerations expressed in Response #1 of this final rule. We do not 
consider the Soil NO<INF>X</INF> Study alone to be sufficient to compel 
replacement of the emissions inventories that were the analytical bases 
of the EPA's proposal, particularly given the study's wide range of 
suggested soil NO<INF>X</INF> emission increases (20 to 51 percent for 
California) and the large uncertainty in the model results.
    Soil NO<INF>X</INF> emissions occur across California's wide range 
of ecological regions \31\ and NO<INF>X</INF> emissions from 
agricultural regions in the State represent a subset of the statewide 
annual soil NO<INF>X</INF> estimate. Within the agricultural regions, 
the amount of soil NO<INF>X</INF> emitted varies based on agricultural 
practices employed (e.g., irrigation; method, timing, and amount of 
fertilizer application; etc.), crop type, temperature, and other 
factors. Additionally, soil NO<INF>X</INF> is not directly emitted 
(e.g., nitrifying bacteria in the soil convert ammonium from various 
sources into NO<INF>X</INF>, some of which is emitted into the 
atmosphere) and involves numerous natural emissions sources and 
processes. Therefore, the production of NO<INF>X</INF> in the soil is 
quite complex and inherently difficult to estimate and model.
---------------------------------------------------------------------------

    \31\ A map of California's ecological regions is available at: 
https://www.epa.gov/eco-research/ecoregion-download-files-state-region-9.
---------------------------------------------------------------------------

    In addition, the commenter did not provide examples or 
recommendations of alternative agricultural practices that might reduce 
soil NO<INF>X</INF> emissions in California. Even if there were known

[[Page 65100]]

alternative practices, it may prove difficult to estimate the effect of 
those potential controls given the complexity of soil NO<INF>X</INF> 
production. Given the complexity in estimating and modeling soil 
NO<INF>X</INF> emissions, the indirect and partially natural source of 
the emissions, the absence of specific alternative measures that could 
be implemented to reduce soil NO<INF>X</INF> emissions, and the 
uncertainty in the effectiveness of potential emission controls, the 
EPA concludes that there is not sufficient information available at 
this time to warrant an evaluation of potential control of soil 
NO<INF>X</INF> emissions in California for purposes of interstate 
transport prongs 1 and 2 for the 2008 ozone NAAQS.
    Therefore, we reaffirm that our approach of evaluating California's 
largest sources of NO<INF>X</INF> emissions and the control measures 
for such sources, including mobile sources (70 percent of the projected 
2017 emissions inventory) and stationary point sources (15 percent of 
the inventory, including EGUs and non-EGU sources), is a reasonable 
means for assessing whether California has satisfied the interstate 
transport requirements of CAA section 110(a)(2)(D)(i)(I) with respect 
to the 2008 ozone NAAQS.
    Comment #3: Lastly, the commenter asserts that measures to control 
NO<INF>X</INF> emissions from cropland soils will bring economic, 
ecosystem, and human health co-benefits to rural California, per the 
recent study. On this basis, the commenter disagrees that the EPA lacks 
discretionary authority under Executive Order 12898 to address 
disproportionate human health or environmental effects and highlights 
the San Joaquin Valley as an area with many communities that suffer 
environmental injustice. The commenter states that the California 
Transport Plan should include measures to control NO<INF>X</INF> 
emissions from agricultural soils to reduce pollution in such 
communities, consistent with Executive Order 12898.
    Response #3: We disagree that the EPA has discretionary authority 
in this rulemaking under Executive Order 12898 to address any 
disproportionate human health or environmental effects in rural 
California. First, Executive Order 12898 applies only to federal agency 
actions that invoke certain federal requirements, such as the National 
Environmental Policy Act or CAA section 309, and it does not apply 
where the EPA is merely approving a state submission as meeting basic 
requirements of the CAA. Second, this rulemaking concerns the 
interstate transport of ozone from California to other states under CAA 
section 110(a)(2)(D)(i)(I), rather than the effect of California's 
NO<INF>X</INF> emissions on communities within California. Thus, the 
commenters suggestion that California should control NO<INF>X</INF> 
emissions from cropland soils to reduce pollution that may affect 
communities in California is outside the scope of this rulemaking. For 
these reasons, Executive Order 12898 is not applicable to this action.

III. EPA Action

    We have reviewed the California Transport Plan for the 2008 ozone, 
2006 PM<INF>2.5</INF>, 2012 PM<INF>2.5</INF>, and 2010 SO<INF>2</INF> 
NAAQS using step-wise processes. Based on this review and additional 
analyses conducted by the EPA to verify and supplement the California 
Transport Plan, and consistent with CAA section 110(a)(2)(D)(i)(I) and 
EPA guidance with respect to interstate transport for these NAAQS, we 
find that California will not significantly contribute to 
nonattainment, or interfere with maintenance, of the 2008 ozone, 2006 
PM<INF>2.5</INF>, 2012 PM<INF>2.5</INF>, and 2010 SO<INF>2</INF> NAAQS 
in any other state. No comments were submitted that change our 
assessment of the California Transport Plan as described in our 
proposed rulemaking. Therefore, as authorized in section 110(k)(3) of 
the Act, the EPA is fully approving the California Transport Plan into 
the California SIP for the requirements of CAA section 
110(a)(2)(D)(i)(I) for these NAAQS.
    In addition, for the 2006 PM<INF>2.5</INF> and 2008 ozone NAAQS, 
the EPA had previously found that California failed to submit the 
required SIP revisions addressing interstate transport prongs 1 and 2 
by certain dates.\32\ Those actions triggered the obligation for the 
EPA to promulgate a federal implementation plan (FIP) for these 
requirements unless the State submitted and the EPA approved a SIP 
submission that addresses the two prongs. As the EPA is fully approving 
the California Transport Plan for these two NAAQS, this final rule also 
removes the obligation for the EPA to promulgate such FIPs.
---------------------------------------------------------------------------

    \32\ 79 FR 63536 (October 24, 2014) for the 2006 
PM<INF>2.5</INF> NAAQS; and 80 FR 39961 (July 13, 2015) for the 2008 
ozone NAAQS.
---------------------------------------------------------------------------

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 Act and 
applicable federal regulations. 42 U.S.C. 7410(k); 40 CFR 52.02(a). 
Thus, in reviewing SIP submissions, the EPA's role is to approve state 
choices, provided that they meet the criteria of the Clean Air 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:
    <bullet> 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);
    <bullet> Is not an Executive Order 13771 (82 FR 9339, February 2, 
2017) regulatory action because SIP approvals are exempted under 
Executive Order 12866;
    <bullet> Does not impose an information collection burden under the 
provisions of the Paperwork Reduction Act (44 U.S.C. 3501 et seq.);
    <bullet> 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.);
    <bullet> 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);
    <bullet> Does not have Federalism implications as specified in 
Executive Order 13132 (64 FR 43255, August 10, 1999);
    <bullet> Is not an economically significant regulatory action based 
on health or safety risks subject to Executive Order 13045 (62 FR 
19885, April 23, 1997);
    <bullet> Is not a significant regulatory action subject to 
Executive Order 13211 (66 FR 28355, May 22, 2001);
    <bullet> Is not subject to requirements of Section 12(d) of the 
National Technology Transfer and Advancement Act of 1995 (15 U.S.C. 272 
note) because application of those requirements would be inconsistent 
with the Clean Air Act; and
    <bullet> Does not provide the EPA with the discretionary authority 
to address, as appropriate, disproportionate human health or 
environmental effects, using practicable and legally permissible 
methods, under Executive Order 12898 (59 FR 7629, February 16, 1994).
    In addition, the SIP is not approved to apply on any Indian 
reservation land or in any other area where the EPA or an Indian tribe 
has demonstrated that a tribe has jurisdiction. In those areas of 
Indian country, the 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).

[[Page 65101]]

    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 February 19, 2019. 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, Ammonia, 
Incorporation by reference, Intergovernmental relations, Nitrogen 
dioxide, Ozone, Particulate matter, Reporting and recordkeeping 
requirements, Sulfur dioxide, Volatile organic compounds.

    Dated: November 30, 2018.
Deborah Jordan,
Acting Regional Administrator, Region IX.

    Part 52, Chapter I, Title 40 of the Code of Federal Regulations is 
amended 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)(512) to read as 
follows:


Sec.  52.220   Identification of plan--in part.

* * * * *
    (c) * * *
    (512) The following plan was submitted on January 19, 2016, by the 
Governor's Designee.
    (i) [Reserved].
    (ii) Additional materials.
    (A) California Air Resources Board (CARB).
    (1) ``California Infrastructure State Implementation Plan (SIP) 
Revision, Clean Air Act Section 110(a)(2)(D),'' adopted December 17, 
2015, (``California Transport Plan'').

0
3. Section 52.283 is amended by adding paragraphs (c)(3), (d)(3), and 
(g)(3) to read as follows:


Sec.  52.283   Interstate Transport.

* * * * *
    (c) * * *
    (3) The requirements of CAA section 110(a)(2)(D)(i)(I) regarding 
significant contribution to nonattainment of the 2006 PM<INF>2.5</INF> 
NAAQS and 2012 PM<INF>2.5</INF> NAAQS in any other state and 
interference with maintenance of the 2006 PM<INF>2.5</INF> NAAQS and 
2012 PM<INF>2.5</INF> NAAQS by any other state.
* * * * *
    (d) * * *
    (3) The requirements of CAA section 110(a)(2)(D)(i)(I) regarding 
significant contribution to nonattainment of the 2008 ozone NAAQS in 
any other State and interference with maintenance of the 2010 ozone 
NAAQS by any other State.
* * * * *
    (g) * * *
    (3) The requirements of CAA section 110(a)(2)(D)(i)(I) regarding 
significant contribution to nonattainment of the 2010 SO<INF>2</INF> 
NAAQS in any other State and interference with maintenance of the 2010 
SO<INF>2</INF> NAAQS by any other State.

[FR Doc. 2018-27477 Filed 12-18-18; 8:45 am]
BILLING CODE 6560-50-P


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