[Federal Register Volume 86, Number 185 (Tuesday, September 28, 2021)]
[Proposed Rules]
[Pages 53571-53576]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2021-20619]


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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 52

[EPA-R09-OAR-2020-0567; FRL-9001-01-R9]


Air Plan Approval; Hawaii; Interstate Transport for the 2015 
Ozone NAAQS

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.

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SUMMARY: The Environmental Protection Agency (EPA) is proposing to 
approve a state implementation plan (SIP) submission from the State of 
Hawaii addressing requirements in the Clean Air Act (CAA or ``Act'') 
regarding interstate transport for the 2015 ozone national ambient air 
quality standards (NAAQS). Hawaii submitted a SIP revision on November 
12, 2019 addressing the CAA provision 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 in any other state (``the good 
neighbor provision''). The EPA is proposing to approve Hawaii's good 
neighbor SIP revision for the 2015 ozone NAAQS.

DATES: Any comments must arrive by October 28, 2021.

ADDRESSES: Submit your comments, identified by Docket ID No. EPA-R09-
OAR-2020-0567 at https://www.regulations.gov. Follow the online 
instructions for submitting comments at Regulations.gov. Once 
submitted, comments cannot be edited or removed from Regulations.gov. 
The EPA may publish any comment received to its public docket. Do not 
submit electronically any information you consider to be Confidential 
Business Information (CBI) or other information whose disclosure is 
restricted by statute. Multimedia submissions (audio, video, etc.) must 
be accompanied by a written comment. The written comment is considered 
the official comment and should include discussion of all points you 
wish to make. The EPA will generally not consider comments or comment 
contents located outside of the primary submission (i.e., on the web, 
cloud, or other file sharing system). For additional submission 
methods, or 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 the full EPA public 
comment policy, information about CBI or multimedia submissions, and 
general guidance on making effective comments, please visit https://www.epa.gov/dockets/commenting-epa-dockets.

FOR FURTHER INFORMATION CONTACT: Tom Kelly, EPA Region IX, (415) 972-
3856, [email protected]. 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.

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

I. Background

    On October 1, 2015, the EPA promulgated a revision to the ozone 
NAAQS (``2015 ozone NAAQS''), lowering the level of both the primary 
and secondary standards to 0.070 parts per million (ppm).\1\ Section 
110(a)(1) of the CAA requires states to submit, within 3 years after 
promulgation of a new or revised standard, SIP submissions meeting the 
applicable requirements of section 110(a)(2).\2\ One of these 
applicable requirements is found in section 110(a)(2)(D)(i)(I), 
otherwise known as the good neighbor provision, which generally 
requires SIPs to contain adequate provisions to prohibit in-state 
emissions activities from having certain adverse air quality effects on 
other states due to interstate transport of pollution. There are two 
so-called ``prongs'' within CAA section 110(a)(2)(D)(i)(I). A SIP for a 
new or revised NAAQS must contain adequate provisions prohibiting any 
source or other type of emissions activity within the state from 
emitting air pollutants in amounts that will: Significantly contribute 
to nonattainment of the NAAQS in another state (prong 1); or interfere 
with maintenance of the NAAQS in another state (prong 2). The EPA and 
states must give independent significance to prong 1 and prong 2 when 
evaluating downwind air quality problems under CAA section 
110(a)(2)(D)(i)(I).\3\
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    \1\ National Ambient Air Quality Standards for Ozone, Final 
Rule, 80 FR 65292 (October 26, 2015). Although the level of the 
standard is specified in the units of ppm, ozone concentrations are 
also described in parts per billion (ppb). For example, 0.070 ppm is 
equivalent to 70 ppb.
    \2\ SIP revisions that are intended to meet the applicable 
requirements of section 110(a)(1) and (2) of the CAA are often 
referred to as infrastructure SIPs and the applicable elements under 
110(a)(2) are referred to as infrastructure requirements.
    \3\ See North Carolina v. EPA, 531 F.3d 896, 909-911 (2008).
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    We note that the EPA has addressed the interstate transport 
requirements of CAA section 110(a)(2)(D)(i)(I) with respect to prior 
ozone NAAQS in several regional regulatory actions, including the 
Cross-State Air Pollution Rule (CSAPR), which addressed interstate 
transport with respect to the 1997 ozone NAAQS as well as the 1997 and 
2006 fine particulate matter standards,\4\ the CSAPR Update, and, most 
recently, the Revised CSAPR Update for the 2008 ozone 
NAAQS.5 6
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    \4\ 76 FR 48208 (August 8, 2011).
    \5\ The Revised Cross-State Air Pollution Rule Update for the 
2008 Ozone NAAQS (86 FR 23054; April 30, 2021) was signed by the EPA 
Administrator on March 15, 2021 and responded to the remand of the 
CSAPR Update (81 FR 74504; October 26, 2016) and the vacatur of a 
separate rule, the CSAPR Close-Out (83 FR 65878; December 21, 2018) 
by the D.C. Circuit. Wisconsin v. EPA, 938 F.3d 303 (D.C. Cir. 
2019); New York v. EPA, 781 F. App'x. 4 (D.C. Cir. 2019).
    \6\ In 2019, the D.C. Circuit Court of Appeals remanded the 
CSAPR Update to the extent it failed to require upwind states to 
eliminate their significant contribution by the next applicable 
attainment date by which downwind states must come into compliance 
with the NAAQS, as established under CAA section 181(a). 938 F.3d 
303, 313.
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    Through the development and implementation of CSAPR and other 
regional rulemakings pursuant to the good neighbor provision,\7\ the 
EPA,

[[Page 53572]]

working in partnership with states, developed the following four-step 
interstate transport framework to address the requirements of the good 
neighbor provision for the ozone NAAQS: (1) Identify downwind air 
quality problems; (2) identify upwind states that impact those downwind 
air quality problems sufficiently such that they are considered 
``linked'' and therefore warrant further review and analysis; (3) 
identify the emissions reductions necessary (if any), applying a 
multifactor analysis, to prevent linked upwind states identified in 
step 2 from contributing significantly to nonattainment or interfering 
with maintenance of the NAAQS at the locations of the downwind air 
quality problems; and (4) adopt permanent and enforceable measures 
needed to achieve those emissions reductions.
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    \7\ In addition to the CSAPR rulemakings, other regional 
rulemakings addressing ozone transport include the NOX 
SIP Call, 63 FR 57356 (October 27, 1998), and the Clean Air 
Interstate Rule (CAIR), 70 FR 25162 (May 12, 2005).
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    The EPA has released several documents containing information 
relevant to evaluating interstate transport with respect to the 2015 
ozone NAAQS. First, on January 6, 2017, the EPA published a notice of 
data availability (NODA) with preliminary interstate ozone transport 
modeling with projected ozone design values for 2023 using a 2011 base 
year platform, on which we requested comment.\8\ In the NODA, the EPA 
used the year 2023 as the analytic year for this preliminary modeling 
because that year aligns with the expected attainment year for Moderate 
ozone nonattainment areas for the 2015 ozone NAAQS.\9\ On October 27, 
2017, we released a memorandum (``2017 memorandum'') containing updated 
modeling data for 2023, which incorporated changes made in response to 
comments on the NODA, and noted that the modeling may be useful for 
states developing SIPs to address good neighbor obligations for the 
2008 ozone NAAQS.\10\ On March 27, 2018, we issued a memorandum 
(``March 2018 memorandum'') noting that the same 2023 modeling data 
released in the 2017 memorandum could also be useful for identifying 
potential downwind air quality problems with respect to the 2015 ozone 
NAAQS at step 1 of the four-step interstate transport framework. The 
March 2018 memorandum also included the then newly available 
contribution modeling results to assist states in evaluating their 
impact on potential downwind air quality problems for the 2015 ozone 
NAAQS under step 2 of the interstate transport framework. The EPA 
subsequently issued two additional memoranda in August and October 
2018, providing additional information to states developing good 
neighbor SIPs for the 2015 ozone NAAQS concerning, respectively, 
potential contribution thresholds that may be appropriate to apply in 
step 2 of the framework, and considerations for identifying downwind 
areas that may have problems maintaining the standard at step 1 of the 
framework.\11\
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    \8\ See Notice of Availability of the Environmental Protection 
Agency's Preliminary Interstate Ozone Transport Modeling Data for 
the 2015 Ozone National Ambient Air Quality Standard (NAAQS), 82 FR 
1733 (January 6, 2017).
    \9\ 82 FR 1735 (January 6, 2017).
    \10\ See Information on the Interstate Transport State 
Implementation Plan Submissions for the 2008 Ozone National Ambient 
Air Quality Standards under Clean Air Act Section 
110(a)(2)(D)(i)(I), October 27, 2017, available in the docket for 
this action or at https://www.epa.gov/interstate-air-pollution-transport/interstate-air-pollution-transport-memos-and-notices.
    \11\ See Analysis of Contribution Thresholds for Use in Clean 
Air Act Section 110(a)(2)(D)(i)(I) Interstate Transport State 
Implementation Plan Submissions for the 2015 Ozone National Ambient 
Air Quality Standards, August 31, 2018) (``August 2018 
memorandum''), and Considerations for Identifying Maintenance 
Receptors for Use in Clean Air Act Section 110(a)(2)(D)(i)(I) 
Interstate Transport State Implementation Plan Submissions for the 
2015 Ozone National Ambient Air Quality Standards, October 19, 2018, 
available in the docket for this action or at https://www.epa.gov/airmarkets/memo-and-supplemental-information-regarding-interstate-transport-sips-2015-ozone-naaqs.
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    On October 30, 2020, in the Notice of Proposed Rulemaking for the 
Revised CSAPR Update, the EPA released and accepted public comment on 
updated 2023 modeling that used the 2016 emissions platform developed 
under the EPA/Multi-Jurisdictional Organization (MJO)/state 
collaborative project as the primary source for the base year and 
future year emissions data.\12\ On March 15, 2021, the EPA signed the 
final Revised CSAPR Update using the same modeling released at 
proposal.\13\ Although Hawaii relied in part on the modeling included 
in the March 2018 memorandum to develop its SIP submission, the EPA now 
proposes to primarily rely on the updated and newly available 2016 base 
year modeling in evaluating this submission. By using the updated 
modeling results, EPA is using the most current and technically 
appropriate information as the primary basis for this proposed 
rulemaking. EPA's independent analysis, which also evaluated historical 
monitoring data, recent ambient air monitoring design values, and 
emissions trends, found that such information provides additional 
support and further substantiates the results of the 2016 base year 
modeling as the basis for this proposed rulemaking. Section II of this 
document and the Air Quality Modeling technical support document (TSD) 
included in the docket for this proposed action contain additional 
detail on this modeling.\14\
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    \12\ See 85 FR 68964, 68981. The results of this modeling are 
included in a spreadsheet in the docket for this action. The 
underlying modeling files are available for public review in the 
docket for the Revised CSAPR Update (EPA-HQ-OAR-2020-0272).
    \13\ 82 FR 23054 (April 30, 2021).
    \14\ See ``Air Quality Modeling Technical Support Document for 
the Proposed Revised Cross-State Air Pollution Rule Update,'' 85 FR 
68964 (October 30, 2020), available in the docket for this action or 
at https://www.epa.gov/csapr/revised-cross-state-air-pollution-rule-update. This TSD was originally developed to support EPA's proposed 
action in the Revised CSAPR Update, as relating to outstanding good 
neighbor obligations under the 2008 ozone NAAQS. While developed in 
this separate context, the data and modeling outputs, including 
interpolated design values for 2021, may be evaluated with respect 
to the 2015 ozone NAAQS and used in support of this action.
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    In the CSAPR, CSAPR Update, and the Revised CSAPR Update, the EPA 
used a threshold of one percent of the NAAQS to determine whether a 
given upwind state was ``linked'' at step 2 of the interstate transport 
framework and would, therefore, contribute to downwind nonattainment 
and maintenance sites identified in step 1. If a state's impact did not 
equal or exceed the one percent threshold, the upwind state was not 
``linked'' to a downwind air quality problem, and the EPA, therefore, 
concluded the state would not significantly contribute to nonattainment 
or interfere with maintenance of the NAAQS in the downwind states. 
However, if a state's impact equaled or exceeded the one percent 
threshold, the state's emissions were further evaluated in step 3, to 
determine what, if any, emissions might be deemed ``significant'' and, 
thus, must be eliminated under the good neighbor provision. The EPA is 
proposing to rely on the one percent threshold (i.e., 0.070 ppb) for 
the purpose of evaluating Hawaii's contributions to nonattainment or 
maintenance of the 2015 ozone NAAQS in downwind areas.
    Several D.C. Circuit court decisions have addressed the issue of 
the relevant analytic year for the purposes of evaluating ozone 
transport air-quality problems. On September 13, 2019, the D.C. Circuit 
issued a decision in Wisconsin v. EPA, remanding the CSAPR Update to 
the extent that it failed to require upwind states to eliminate their 
significant contribution by the next applicable attainment date by 
which downwind states must come into compliance with the NAAQS, as 
established under CAA section 181(a).\15\
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    \15\ 938 F.3d 303, 313.
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    On May 19, 2020, the D.C. Circuit issued a decision in Maryland v. 
EPA

[[Page 53573]]

that cited the Wisconsin decision in holding that the EPA must assess 
the impact of interstate transport on air quality at the next downwind 
attainment date, including Marginal area attainment dates, in 
evaluating the basis for the EPA's denial of a petition under CAA 
section 126(b).\16\ The court noted that ``section 126(b) incorporates 
the Good Neighbor Provision,'' and, therefore, ``the EPA must find a 
violation [of section 126] if an upwind source will significantly 
contribute to downwind nonattainment at the next downwind attainment 
deadline. Therefore, the agency must evaluate downwind air quality at 
that deadline, not at some later date.'' \17\ The EPA interprets the 
court's holding in Maryland as requiring the Agency, under the good 
neighbor provision, to assess downwind air quality by the next 
applicable attainment date, including a Marginal area attainment date 
under section 181 for ozone nonattainment.\18\ The Marginal area 
attainment date for the 2015 ozone NAAQS is August 3, 2021.\19\ 
Historically, the EPA has considered the full ozone season prior to the 
attainment date as supplying an appropriate analytic year for assessing 
good neighbor obligations. While this would be 2020 for an August 2021 
attainment date (which falls within the 2021 ozone season running from 
May 1 to September 30), in this circumstance, when the 2020 ozone 
season is wholly in the past, it is appropriate to focus on 2021 in 
order to address good neighbor obligations to the extent possible by 
the 2021 attainment date. The EPA does not believe it would be 
appropriate to select an analytical year that is wholly in the past, 
because the agency interprets the good neighbor provision as forward 
looking.\20\ Consequently, in this proposed action the EPA will use the 
analytical year of 2021 to evaluate Hawaii's good neighbor obligations 
with respect to the 2015 ozone NAAQS.\21\
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    \16\ Maryland v. EPA, 958 F.3d 1185, 1203-04 (D.C. Cir. 2020).
    \17\ Id. at 1204.
    \18\ We note that the court in Maryland did not have occasion to 
evaluate circumstances in which EPA may determine that an upwind 
linkage to a downwind air quality problem exists at steps 1 and 2 of 
the interstate transport framework by a particular attainment date, 
but for reasons of impossibility or profound uncertainty the Agency 
is unable to mandate upwind pollution controls by that date. See 
Wisconsin, 938 F.3d at 320. The D.C. Circuit noted in Wisconsin that 
upon a sufficient showing, these circumstances may warrant 
flexibility in effectuating the purpose of the good neighbor 
provision. Such circumstances are not at issue in the present 
action.
    \19\ CAA section 181(a); 40 CFR 51.1303; 83 FR 25776 (June 4, 
2018, effective Aug. 3, 2018).
    \20\ See 85 FR at 68981; see also Wisconsin, 938 F.3d at 322.
    \21\ EPA recognizes that by the time final action is taken with 
respect to this SIP submission, the 2021 ozone season will be wholly 
in the past. As discussed below, the available modeling information 
indicates that our analysis would not change even using 2023 as the 
analytic year. The 2023 modeling results are included in the ``Ozone 
Design Values and Contributions Revised CSAPR Update.xlsx'', 
included in the docket for this action.
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II. HDOH SIP Submission

    The Hawaii Department of Health (HDOH) submitted its good neighbor 
SIP submission for the 2015 ozone NAAQS by letter dated November 12, 
2019.\22\ The submittal included documentation of public participation 
proceedings to meet the requirements of CAA section 110(a)(2) and 40 
CFR 51.102. The EPA determined that the submittal was complete on 
November 13, 2019.\23\
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    \22\ Letter dated November 12, 2019, from Bruce Anderson, Ph.D., 
Director of Health, HDOH, to Mike Stoker, Regional Administrator, 
U.S. EPA, Region IX.
    \23\ Letter dated November 13, 2019, from Elizabeth J. Adams, 
Acting Director, Air Division, EPA Region 9, to Bruce Anderson, 
HDOH.
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    HDOH concluded that Hawaii does not significantly contribute to 
nonattainment or interfere with maintenance of the 2015 ozone NAAQS in 
any other state, citing the distance from Hawaii to the continental 
U.S, the relatively small quantity of ozone precursor emissions in 
Hawaii, and an evaluation of ozone transport using trajectory analysis 
of emissions from Hawaii to the continental U.S.
    In the HDOH submittal, the State notes that Hawaii is approximately 
2,390 miles from the nearest state, California. HDOH also points to 
Hawaii's 2016 Annual Summary of Air Quality Data to note that Hawaii is 
in attainment for all NAAQS and compares Hawaii's ozone precursor 
emissions to those of California and Nevada. Hawaii's analysis states 
that emissions of ozone precursors, nitrogen oxides (NOX) 
and volatile organic compounds (VOC), from Hawaii were 7.57 and 6.28 
percent, respectively, of California's emissions in 2011 and 7.95 and 
5.21 percent in 2014.\24\ Cumulatively, emissions of ozone precursors 
from Hawaii in 2011 and 2014 were 6.97 and 6.54 percent, respectively, 
of California's emissions. Furthermore, HDOH points out that the 
State's ozone precursor emissions have exhibited a downward trend, 
having decreased since the 2011 National Emissions Inventory (NEI), and 
notes that their emissions continue to be relatively low compared to 
California. To demonstrate that Hawaii's ozone precursor emissions 
would not significantly contribute to interstate transport, even if 
California and Hawaii were directly adjacent to each other, the 
submittal compares Hawaii's ozone precursor emissions to those of 
Nevada, which shares a border with California, but does not 
significantly contribute to interstate transport to any other 
state.\25\ Emissions of NOX and VOCs from Hawaii were 51.24 
and 49.28 percent, respectively, of Nevada's emissions in 2014. 
Cumulatively, emissions of ozone precursors from Hawaii in 2014 were 
50.35 percent of Nevada's emissions.
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    \24\ 2014 data was the most recent available at the time Hawaii 
prepared its submittal.
    \25\ Hawaii cited EPA's 2015 Ozone NAAQS Interstate Transport 
Assessment Design Values and Contributions spreadsheet, released in 
a memorandum from Peter Tsirigotis, to Regional Air Division 
Directors, Region 1-10, dated March 27, 2018. See ``2015 Ozone NAAQS 
Interstate Transport Assessment Design Values and Contributions'' at 
https://www.epa.gov/airmarkets/memo-and-supplemental-information-regarding-interstate-transport-sips-2015-ozone-naaqs. File name: 
Updated_2023_modeling_dvs_collective_contributions.xlsx.
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    Appendix 1 of the HDOH submittal provides trajectories for 
emissions from Hawaii's Campbell Industrial Park, which includes a 
refinery and power generation facility, based on 2010 meteorological 
data during January and July. HDOH found that a comparison between the 
trajectory modeling results and ozone monitoring data supports the 
conclusion that it is highly unlikely that Hawaii is currently 
impacting nonattainment or maintenance areas of other states and that 
it is highly unlikely to do so in the future.

III. EPA Evaluation

    As explained in Section I of this document, in consideration of the 
holdings in Wisconsin and Maryland, the EPA's four-step interstate 
transport analysis relies on 2021 as the relevant attainment year for 
evaluating Hawaii's good neighbor obligations with respect to the 2015 
ozone NAAQS.\26\ In step 1, we identify locations where the Agency 
expects there to be nonattainment or maintenance receptors for the 2015 
8-hour ozone NAAQS in the 2021 analytic future year. Where the EPA's 
analysis shows that a monitoring site does not fall under the 
definition of a

[[Page 53574]]

nonattainment or maintenance receptor, that site is excluded from 
further analysis under the EPA's four-step interstate transport 
framework. For monitoring sites that are identified as nonattainment or 
maintenance receptors in 2021, we proceed to the next step of our four-
step framework by identifying the upwind state's contribution to those 
receptors.
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    \26\ We recognize that Hawaii and other states may have been 
influenced by EPA's 2018 guidance memos (issued prior to the 
Wisconsin and Maryland decisions) in making good neighbor 
submissions that relied on EPA's modeling of 2023. When there are 
intervening changes in relevant law or legal interpretation of CAA 
requirements, states are generally free to withdraw, supplement, 
and/or re-submit their SIP submissions with new analysis (in 
compliance with CAA procedures for SIP submissions). While Hawaii 
has not done this, as explained in this section, the independent 
analysis EPA has conducted at its discretion confirms that the 
state's submission in this instance is ultimately approvable.
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    The EPA's approach to identifying ozone nonattainment and 
maintenance receptors in this proposed action is consistent with the 
approach used in the CSAPR, the CSAPR Update, and the Revised CSAPR 
Update. The EPA's approach gives independent consideration to both the 
``contribute significantly to nonattainment'' and the ``interfere with 
maintenance'' prongs of section 110(a)(2)(D)(i)(I), consistent with the 
D.C. Circuit's direction in North Carolina.\27\ Further, in its 
decision on the remand of CSAPR from the Supreme Court in the EME Homer 
City case, the D.C. Circuit confirmed that the EPA's approach to 
identifying maintenance receptors in CSAPR comported with the court's 
prior instruction to give independent meaning to the ``interfere with 
maintenance'' prong in the good neighbor provision.\28\
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    \27\ 531 F.3d at 910-911 (holding that the EPA must give 
``independent significance'' to each prong of CAA section 
110(a)(2)(D)(i)(I)).
    \28\ EME Homer City Generation, L.P. v. EPA, 795 F.3d 118, 136 
(D.C. Cir. 2015) (EME Homer City II).
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    For purposes of this proposed action, the EPA identifies 
nonattainment receptors as those monitoring sites that are projected to 
have average design values that exceed the NAAQS and that are also 
measuring nonattainment based on the most recent monitored design 
values.\29\ This approach is consistent with prior transport 
rulemakings, such as the CSAPR Update, where the EPA defined 
nonattainment receptors as those areas that both currently monitor 
nonattainment and that the EPA projects will be in nonattainment in the 
future analytic year.\30\ In addition, in this proposed action, the EPA 
identifies a receptor to be a ``maintenance'' receptor for purposes of 
defining interference with maintenance, consistent with the method used 
in CSAPR and upheld by the D.C. Circuit in EME Homer City 
II.31 32
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    \29\ Average projected design values are based on the average 
design value during the five-year base monitoring period (i.e., 
2014-2016, 2015-2017 and 2016-2018), as discussed in the Final 
Revised Cross-State Air Pollution Rule Update for the 2008 Ozone 
NAAQS (86 FR 23054, April 30, 2021) and further clarified in the Air 
Quality Modeling Technical Support Document for the Final Revised 
Cross State Air Pollution Rule Update, which is available in the 
docket for that rulemaking EPA-HQ-OAR-2020-0272.
    \30\ See 81 FR 74504 (October 26, 2016). The Revised CSAPR 
Update also used this approach. See 86 FR 23054 (April 30, 2021). 
This same concept, relying on both current monitoring data and 
modeling to define nonattainment receptors, was also applied in 
CAIR. See 70 FR 25241 (January 14, 2005); see also North Carolina, 
531 F.3d at 913-14 (affirming as reasonable EPA's approach to 
defining nonattainment in CAIR).
    \31\ See 795 F.3d at 136.
    \32\ Maximum projected design values are based on the maximum 
design value during the five-year base monitoring period from 2014 
to 2018.
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    Recognizing that nonattainment receptors are also, by definition, 
maintenance receptors, the EPA often uses the term ``maintenance-only'' 
to refer to receptors that are not also nonattainment receptors. 
Consistent with the methodology described above, monitoring sites with 
a projected maximum design value that exceeds the NAAQS, but with a 
projected average design value that is below the NAAQS, are identified 
as maintenance-only receptors. In addition, those sites that are 
currently measuring ozone concentrations below the level of the 
applicable NAAQS but are projected to be nonattainment based on the 
average design value and that, by definition, are projected to have a 
maximum design value above the standard are also identified as 
maintenance-only receptors.
    To evaluate future air quality in steps 1 and 2 of the interstate 
transport framework, the EPA is using the 2016 and 2023 base case 
emissions developed under the EPA/MJO/state collaborative emissions 
modeling platform project as the primary source for base year and 2023 
future year emissions data for this proposed rule. Because this 
platform does not include emissions for 2021, the EPA developed an 
interpolation technique based on modeling for 2023 and measured ozone 
data to determine ozone concentrations for 2021. To estimate average 
and maximum design values for 2021, the EPA first performed air quality 
modeling for 2016 and 2023 to obtain design values in 2023. The 2023 
design values were then coupled with the corresponding 2016 measured 
design values to estimate design values in 2021. Details on the 
modeling, including the interpolation methodology, can be found in the 
Air Quality Modeling TSD, in the docket for this proposed action.
    To quantify the contribution of emissions from specific upwind 
states on 2021 8-hour design values for the identified downwind 
nonattainment and maintenance receptors, the EPA first performed 
nationwide, state-level ozone source apportionment modeling for 2023. 
The source apportionment modeling provided contributions to ozone from 
precursor emissions of anthropogenic NOX and VOCs in each 
individual state. The modeled contributions were then applied in a 
relative sense to the 2021 average design value to estimate the 
contributions in 2021 from each state to each receptor. Details on the 
source apportionment modeling and the methods for determining 
contributions in 2021 are in the Air Quality Modeling TSD in the 
docket.
    The EPA generally does not consider modeling to be necessary for 
isolated states like Hawaii for the purposes of evaluating interstate 
transport. Therefore, Hawaii was not included in the modeling domain, 
and the apportionment modeling analysis described above does not 
calculate emissions contributions from Hawaii to the downwind 
nonattainment and maintenance areas identified in step 1 in the 
contiguous United States. In lieu of apportionment modeling, at step 2 
of the interstate transport framework, a proper and well-supported 
weight of evidence approach can provide sufficient information for 
purposes of addressing Hawaii's interstate transport for the 2015 ozone 
NAAQS. In a weight of evidence analysis, no single piece of information 
is by itself dispositive of the issue. Instead, the total weight of all 
the evidence taken together is used to evaluate significant 
contribution to nonattainment or interference with maintenance of the 
2015 ozone NAAQS in another state. In the weight of evidence analysis 
detailed below, we consider (1) the distance between sources in Hawaii 
and the nonattainment and maintenance receptors identified in step 1; 
(2) the relative magnitude of state-wide emissions of ozone precursors; 
(3) an evaluation of prevailing wind direction that may impact of 
transport of emissions from Hawaii during the summer ozone season; and 
(4) a comparison of Hawaii's impact on California to California's 
impact on Connecticut.
    The state with the nearest nonattainment receptors to Hawaii is 
California, based on the modeling supporting the Revised CSAPR 
Update.\33\ The nearest California

[[Page 53575]]

nonattainment receptor is the Modesto-14th Street monitor, located in 
Stanislaus County, which is 2,384 miles from the easternmost edge of 
Hawaii.\34\ The next closest nonattainment receptors outside of 
California are located in Douglas County, Jefferson County, and Larimer 
County in Colorado, and Davis County and Salt Lake County in Utah.
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    \33\ Projected ozone 2021 receptor concentrations and interstate 
contributions are contained in spreadsheet titled, 
ozone_design_values_contributions_proposed_revised_csapr_update.xlsx.
 The spreadsheet and accompanying TSD, Air Quality Modeling TSD for 
the Proposed Revised Cross-State Air Pollution Rule Update, are 
contained in the docket for the Proposed Revised CSAPR Update, 
Docket Number EPA-HQ-OAR-2020-0272, and have also been included in 
the docket for this action. In total, in California 22 counties have 
nonattainment receptors and 2 counties have maintenance-only 
receptors.
    \34\ Determination of the nearest nonattainment and maintenance-
only receptors was based on final 2020 Ozone Design values. Final 
2020 design value reports can be found at https://www.epa.gov/air-trends/air-quality-design-values#report. California has numerous 
other nonattainment receptors in the following counties: Calaveras, 
El Dorado, Fresno, Imperial, Kern, Los Angeles, Madera, Mariposa, 
Merced, Nevada, Orange, Placer, Riverside, Sacramento, San 
Bernardino, San Diego, San Joaquin, Stanislaus, Tulare, and 
Tuolumne.
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    The nearest California maintenance-only receptor to Hawaii is the 
Tracy-Airport monitor, located in San Joaquin County, which is 2,363 
miles from the easternmost edge of Hawaii.\35\ The next closest 
maintenance-only receptors outside of California are in Yuma County, 
Arizona; Clark County, Nevada; Dona Ana County, New Mexico; and Weber 
County, Utah.
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    \35\ Monitor ID: 60773005.
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    Sheer distance alone makes it unlikely that emissions from Hawaii 
contribute to nonattainment or interfere with maintenance in these 
states. However, we also compare the emissions of ozone precursors from 
Hawaii to those of other western states.\36\ Hawaii's emissions of 
ozone precursors are substantially lower than emissions from other 
western states, as shown in Table 1.\37\ The table represents the most 
recent data available on emissions of ozone precursors. NEI data, which 
is released every three years, is not yet available for 2020.
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    \36\ Emissions estimates downloaded from the EPA's National 
Emissions Inventory, datasets: 2017NEI_Apr2020, 2014 NEI Final V2, 
on January 4 and 5, 2021, and saved as Excel spreadsheet files in 
the docket for this action.
    \37\ In this analysis, we focus primarily on 2017 emissions. The 
most recent available. The Docket for this document contains 
additional information about Event Emissions, which are comprised of 
wildfire, prescribed fire and agricultural burning.

                                                         Table 1--Emissions of Ozone Precursors
                                                                   [Tons per year] \a\
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                        Pollutant                                               NOX                                             VOC
--------------------------------------------------------------------------------------------------------------------------------------------------------
                          Year                                 2011            2014            2017            2011            2014            2017
--------------------------------------------------------------------------------------------------------------------------------------------------------
HI......................................................          54,398          43,061          40,809          38,781          26,593          31,079
AZ......................................................         241,993         215,643         163,779         167,951         120,100         141,160
CA......................................................         724,362         546,495         466,555         617,658         539,159         527,313
NV......................................................          99,234          84,746          69,539          68,526          50,601          68,547
OR......................................................         147,112         125,922         115,886         152,142         103,811         126,818
UT......................................................         178,586         172,488          90,975         217,880         176,188         135,231
--------------------------------------------------------------------------------------------------------------------------------------------------------
Source: Data lists all point, nonpoint, onroad and nonroad emissions from EPA's National Emissions Inventory downloaded from EPA's Emissions Information
  System, files 2017NEI_Apr2020, 2014 NEI Final V2, 2011 NEI V2.
\a\ Biogenic emission from plants and soil and wildfire emissions have been excluded from this data.

    The relative magnitude of Hawaii's emissions compared to Arizona, 
California, Nevada, Oregon, and Utah, coupled with the distance between 
Hawaii and these states, further indicates that Hawaii is unlikely to 
contribute to nonattainment or interfere with maintenance in 
California, or any other state.
    The next step in our analysis is to look at prevailing wind 
direction in Hawaii. In the trajectory analysis in Appendix 1 of the 
State's submittal, HDOH concluded that the predominant transport 
patterns in January and July of 2010--which are from the northeast to 
the southwest (i.e., generally opposite the direction from Hawaii to 
the location of nonattainment and maintenance-only receptors in the 
U.S.)--support the conclusion that Hawaii is unlikely to contribute to 
nonattainment or interfere with maintenance in California or other 
western states.\38\ While HDOH only analyzed wind trajectories in 
January and July of 2010, Hawaii's 2017 Regional Haze SIP contains 2013 
and 2015 wind rose plots, which also illustrate that the predominant 
wind transport patterns year-round blow from northeast to 
southwest.\39\ This is further verified by the National Weather 
Service, which lists persistent trade winds, the prevailing easterly 
winds \40\ that circle the earth near the equator as a result of the 
earth's rotation, from the northeast as a feature of Hawaii's 
climate.\41\ Based on the State's trajectory analysis and wind rose 
plots from its 2017 Regional Haze SIP, along with information from the 
National Weather Service, we expect emissions from Hawaii would 
initially travel westwards before turning eastwards on the vast 
majority of days. This would make the pathway to the continental U.S. 
considerably longer than the more than 2,000 miles separating the 
continental U.S. from Hawaii. These trajectories further indicate that 
Hawaii is unlikely to contribute to nonattainment or interfere with 
maintenance in California or any other state.
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    \38\ The U.S. EPA has also relied on this trajectory analysis in 
approving Hawaii's State Implementation Plan submittals addressing 
interstate transport for the 2008 ozone NAAQS (84 FR 40266, 
September 13, 2019, see the proposed rule at 84 FR 6736, February 
28, 2019), and the 1997 ozone NAAQS (77 FR 47530, October 9, 2012). 
See Technical Support Document, Evaluation of 2011 Hawaii 
Infrastructure SIP for 1997 Ozone; 1997 Particulate Matter; and 2006 
Particulate Matter NAAQS, U.S. EPA, Region 9, March 2012.
    \39\ Appendix C, 5 Year Regional Haze Progress Report for the 
Federal Implementation Plan, Hawaii Department of Health, October 
2017. The EPA approved the Regional Haze Progress Report on May 13, 
2019 (84 FR 14634).
    \40\ In meteorology, wind direction is described as the 
direction from which the wind is blowing (i.e., the Hawaiian trade 
winds blow from the northeast to the southwest), see https://www.weather.gov/cae/weatherterms.html.
    \41\ U.S. Department of Commerce, National Oceanic and 
Atmospheric Association (NOAA). ``Honolulu, HI.'' Pacific Region 
Headquarters, NOAA's National Weather Service, https://www.weather.gov/hfo/climate_summary, accessed on June 28, 2021.
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    Finally, we compare the impact of Hawaii on California, with 
California's impact on Connecticut, because the distance between Hawaii 
and California, and Connecticut and California, is roughly equivalent. 
As previously mentioned, we have modeled contributions among the 
continental states in the Revised CSAPR Update. In terms of distance, 
Hawaii is slightly farther to nonattainment and maintenance-only 
receptors in California, at 2,384 and 2,363 miles, respectively, than 
California is to nonattainment and maintenance only

[[Page 53576]]

receptors in Connecticut, which are 2,263 and 2,285 miles away, 
respectively.\42\ California's contribution to these monitors is 0.03 
ppb to both the nonattainment and maintenance-only receptors in 2021, 
which represents the maximum contribution of California to any 
nonattainment and maintenance-only receptor in Connecticut. This is 
well below the threshold of 1 percent of the NAAQS that would link the 
two states, triggering further review in steps 3 and 4 of the 
interstate transport analysis framework. Given that the distance 
between California and Connecticut is comparable to the distance 
between Hawaii and California, and ozone precursor emissions from 
California are more than 10 times larger than ozone precursor emissions 
from Hawaii, because California's contributions to Connecticut are well 
below the 1 percent threshold, it is reasonable to conclude that 
Hawaii's contribution to California would also be below the 1 percent 
threshold. Therefore, it is not necessary to evaluate potential 
NOX reductions as part of step 3 in the EPA's four-step 
interstate transport framework.
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    \42\ Nonattainment Receptor at Monitor ID 90019003, Fairfield, 
CT and Maintenance-Only Receptor at Monitor ID 90090027, New Haven, 
CT.
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    Based on the weight of evidence, including (1) the distance between 
Hawaii and California, (2) the relative magnitude of ozone precursor 
emissions from Hawaii, (3) the predominant wind direction of the trade 
winds in Hawaii, and (4) the comparison to the impact of ozone 
precursor emissions from California on Connecticut, we propose to find 
that Hawaii will not significantly contribute to nonattainment or 
interfere with maintenance in any other state.

IV. The EPA's Proposed Action

    Based on our review of the interstate transport SIP submission from 
HDOH to address the 2015 ozone NAAQS and the additional analysis 
discussed in this document, we propose to find that emissions from 
Hawaii will not significantly contribute to nonattainment or interfere 
with maintenance of the 2015 ozone NAAQS in any other state. 
Accordingly, we propose to approve the HDOH Submittal as satisfying the 
requirements of CAA section 110(a)(2)(D)(i)(I) for the 2015 ozone 
NAAQS.

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

List of Subjects in 40 CFR Part 52

    Environmental protection, Air pollution control, Incorporation by 
reference, Nitrogenoxides, Volatile organic compounds, Interstate 
transport, Infrastructure SIP.

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

    Dated: September 18, 2021.
Deborah Jordan,
Acting Regional Administrator, Region IX.
[FR Doc. 2021-20619 Filed 9-27-21; 8:45 am]
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