# Response to Clean Air Act Section 126(b) Petition From New York

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URL: https://www.frixlaw.com/law-library/documents/fr%3A2019-21207

## Record

- **Collection:** Federal Register
- **Document type:** Rule
- **Published:** October 18, 2019
- **Citation:** 84 FR 56058

## Text

ENVIRONMENTAL PROTECTION AGENCY
40 CFR Part 52
[EPA-HQ-OAR-2018-0170; FRL-10000-58-OAR]
RIN 2060-AU04
Response to Clean Air Act Section 126(b) Petition From New York

AGENCY:

Environmental Protection Agency (EPA).

ACTION:

Notification of final action on petition.

SUMMARY:

The Environmental Protection Agency (EPA) is denying a Clean Air Act (CAA or Act) petition submitted by the State of New York on March 12, 2018. The petition requested that the EPA make a finding that emissions from a group of hundreds of identified sources in nine states (Illinois, Indiana, Kentucky, Maryland, Michigan, Ohio, Pennsylvania, Virginia and West Virginia) significantly contribute to nonattainment and interfere with maintenance of the 2008 and 2015 ozone national ambient air quality standards (NAAQS) in Chautauqua County and the New York Metropolitan Area (NYMA) in violation of the good neighbor provision. The EPA is denying the petition because the petitioner, New York, has not demonstrated, and the EPA did not independently find, that the group of identified sources emits or would emit in violation of the good neighbor provision for the 2008 or 2015 ozone NAAQS in Chautauqua County and the NYMA.

DATES:

This final action is effective on October 18, 2019.

ADDRESSES:

The EPA has established a docket for this action under Docket ID No. EPA-HQ-OAR-2018-0170. All documents in the docket are listed and publicly available at
http://www.regulations.gov.
Publicly available docket materials are also available in hard copy at the Air and Radiation Docket and Information Center, EPA/DC, EPA William Jefferson Clinton West Building, Room 3334, 1301 Constitution Avenue NW, Washington, DC. The Public Reading Room is open from 8:30 a.m. to 4:30 p.m., Monday through Friday, excluding legal holidays. The telephone number for the Public Reading Room is (202) 566-1744 and the telephone number for the Air and Radiation Docket and Information Center is (202) 566-1742. For additional information about the EPA's public docket, visit the EPA Docket Center homepage at:
http://www.epa.gov/epahome/dockets.htm.

FOR FURTHER INFORMATION CONTACT:

Please direct questions concerning this final action to Beth W. Palma, U.S. EPA, Office of Air Quality Planning and Standards, Air Quality Policy Division, Mail Code C539-04, Research Triangle Park, NC 27711, telephone (919) 541-5432, email at
palma.elizabeth@epa.gov.

SUPPLEMENTARY INFORMATION:

The information in this document is organized as follows:

I. General Information

A. Executive Summary of the EPA's Decision on the CAA Section 126(b) Petition From New York

B. The CAA Section 126(b) Petition From New York

C. Summary of the EPA's May 6, 2019, Proposal

II. Background and Legal Authority

A. Ground-Level Ozone and the Interstate Transport of Ozone

B. CAA Sections 110 and 126

C. The EPA's Historical Approach To Addressing Interstate Transport of Ozone Under the Good Neighbor Provision

III. The EPA's Final Response to the CAA Section 126(b) Petition From New York

A. Reasonableness of Applying the Four-Step Interstate Transport Framework for This Action

B. The EPA's Standard of Review for This CAA Section 126(b) Petition Regarding the 2008 and 2015 8-Hour Ozone NAAQS

C. The EPA's Evaluation of Whether the Petition Is Sufficient To Support a CAA Section 126(b) Finding

IV. Determinations Under CAA Section 307(b)(1) and (d)

V. Statutory Authority

I. General Information

A. Executive Summary of the EPA's Decision on the CAA Section 126(b) Petition From New York

In March 2018, the State of New York submitted a petition requesting that the EPA make a finding pursuant to CAA section 126(b) that emissions from approximately 350 facilities in nine states significantly contribute to nonattainment and/or interfere with maintenance of the 2008 and 2015 ozone NAAQS in violation of CAA section 110(a)(2)(D)(i)(I), otherwise known as the good neighbor provision. On May 6, 2019, the EPA issued a proposal to deny the CAA section 126(b) petition from New York. 84 FR 22787 (May 20, 2019). The Agency solicited comments on the proposal and hosted a public hearing on June 11, 2019, during which four speakers testified. The EPA also received 44 written comments submitted to the docket on the proposed denial. This
Federal Register
notification addresses certain significant comments the Agency received. The EPA addressed the remaining comments in the separate Response to Comments (RTC) document available in the docket for this action.

As described in further detail in this notification, the EPA is finalizing the denial of the CAA section 126(b) petition submitted by the State of New York. Generally, the New York petition (and comments supportive of the EPA granting this petition) suggests that residents of New York are exposed to unhealthy levels of ground-level ozone pollution. The petition identifies approximately 350 electric generating unit (EGU) facilities and non-EGU facilities emitting, or projected to emit, 400 tons per year or more of nitrogen oxides (NO
X
) in nine upwind states and requests that the EPA establish permanent and enforceable emissions limitations for the named major NO
X
sources at levels designed to prevent them from significantly contributing to nonattainment or interfering with maintenance of the 2008 and 2015 ozone NAAQS in New York State. In crafting this final action, the EPA has considered public comments on its May 6, 2019, proposal to deny this petition.

Consistent with the EPA's proposal and based on the best data and information available to the Agency at this time, the Agency is finalizing its denial of this petition. This denial is based on New York's failure to meet its statutory burden to demonstrate that the group of sources identified in the petition emits or would emit in violation of the good neighbor provision for the 2008 or 2015 ozone NAAQS with respect to either Chautauqua County or the New York-Northern New Jersey-Long Island, New York-New Jersey-Connecticut area (hereafter, the New York metropolitan area or NYMA).

As indicated in the EPA's proposal, the EPA evaluated New York's CAA section 126(b) petition consistent with the same four-step interstate transport framework that the EPA has used in previous regulatory actions addressing regional ozone transport problems. The EPA's denial rests on both the first and third steps of this framework. With respect to the 2008 and 2015 ozone NAAQS in Chautauqua County, the EPA is denying the petition at step 1 of the framework (
i.e.,
whether there will be a downwind air quality problem relative to the relevant NAAQS) based on the conclusion that the petition does not provide sufficient information to indicate that Chautauqua County should be considered a nonattainment or maintenance receptor pursuant to the good neighbor provision. With respect to the 2008 ozone NAAQS in the NYMA, the EPA is also denying the petition at step 1 of the framework based on the conclusion that the

petition does not provide sufficient information to indicate that the NYMA should be considered a nonattainment or maintenance receptor pursuant to the good neighbor provision. Furthermore, the EPA's own independent analysis of available information indicates that there is not currently, nor is there projected to be in 2023, an air quality problem with respect to either NAAQS in Chautauqua County, and that in 2023 there is not projected to be any further air quality problem with respect to the 2008 ozone NAAQS in the NYMA.
1

Thus, for these areas and NAAQS, the EPA has found that the petition has not met its burden at step 1 of the four-step interstate transport framework to demonstrate that the group of identified sources either emits or would emit pollution in violation of the good neighbor provision. With respect to the 2015 ozone NAAQS in the NYMA, the Agency's 2023 modeling shows a relevant downwind air quality problem, and, thus, the EPA is not denying this portion of the petition with respect to step 1.

1
The EPA notes that on September 13, 2019, the D.C. Circuit issued an opinion remanding the Cross State Air Pollution Rule Update (CSAPR Update, 81 FR 74504 (October 26, 2016)) in
Wisconsin
v.
EPA,
No. 16-1406. The court held that the rule is inconsistent with the CAA because it does not fully address upwind states' obligations under the good neighbor provision by the relevant attainment date for downwind areas. Nonetheless, the EPA is subject to a court-ordered deadline to take final action on New York's CAA section 126(b) petition by September 20, 2019. As explained in this notification, the EPA is finalizing its denial of New York's CAA section 126(b) petition, in part, because the petitioner did not meet its burden to demonstrate both that there is a relevant downwind air quality under the good neighbor provision in a relevant future year in either Chautauqua County or the NYMA, and that there are cost-effective emissions reductions available at the named sources. This basis for denial based on Petitioner's failure to meet its burden is independent and severable from any portion of the denial based on the EPA's discretionary evaluation of downwind air quality in New York using the Agency's 2023 modeling data. The EPA may make any necessary or appropriate modifications to this final action subsequently to reflect its understanding of the court's holding in
Wisconsin.

The EPA is additionally denying the petition as to all areas for the 2008 and 2015 NAAQS at step 3 of the framework (
i.e.,
whether, considering cost and air quality factors, emissions from sources in the named state(s) will significantly contribute to nonattainment or interfere with maintenance of a NAAQS at a receptor in another state). The EPA has found that material elements in the petition's assessment of whether the sources may be further controlled through implementation of cost-effective controls are insufficient and, thus, New York did not meet its step 3 burden to demonstrate that the named sources currently emit or would emit in violation of the good neighbor provision with respect to the relevant ozone NAAQS.
2

2
The EPA solicited comment on whether to also deny the petition because the petitioner did not sufficiently justify that its identification of such a large, undifferentiated number of sources located in numerous upwind states constitutes a “group of stationary sources” within the context of CAA section 126(b). Based on the other bases for denial, the EPA does not need to reach the question of whether the petitioners' failed to sufficiently justify its interpretation of a “group of stationary sources” but notes that the absence of supporting information for such a determination makes the Agency unlikely to side with petitioners on the information provided.

In making this final decision, the EPA reviewed the petition from New York, the public comments received, the relevant statutory authorities and other relevant materials. Accordingly, the EPA denies the CAA section 126(b) petition from New York.

The remainder of this notification is organized as follows: The General Information part of this notification (Section I) continues with a summary of the relevant issues raised in New York's CAA section 126(b) petition and a summary of the EPA's May 6, 2019, proposed action. Section II of this notification provides background material and information regarding the EPA's approach to addressing the interstate transport of ozone under CAA sections 110(a)(2)(D)(i)(I) and 126(b). Section III of this notification discusses the EPA's standard of review for this action and details the bases for the EPA's final action to deny this petition, including responses to significant comments received on the proposal.

B. The CAA Section 126(b) Petition From New York

On March 12, 2018, the State of New York, through the New York State Department of Environmental Conservation (NY DEC), submitted a CAA section 126(b) petition alleging that emissions from a group of specified upwind sources in Illinois, Indiana, Kentucky, Maryland, Michigan, Ohio, Pennsylvania, Virginia and West Virginia significantly contribute to nonattainment and interfere with maintenance of the 2008 and 2015 ozone NAAQS in the NYMA and in Chautauqua County in western New York.

The petition contends that, although the Chautauqua County area (
i.e.,
the area in and around Jamestown, New York) was at the time of petition submittal (and is currently) attaining both the 2008 and the 2015 ozone NAAQS, the area may have difficulty maintaining its attainment status in the future. The petition also explains that the NYMA is currently designated nonattainment for the 2008 ozone NAAQS and, at the time New York submitted the petition, the area would likely be designated nonattainment for the 2015 ozone NAAQS.
3

The petition further asserts that all three states in the multistate NYMA (
i.e.,
New York, New Jersey and Connecticut) have surpassed their three-percent-per-year emissions reductions requirements for the 2008 NAAQS; yet certified monitoring data through 2016 and (at the time of the petition submittal) preliminary 2017 data indicate that the area is not attaining the 2008 NAAQS, with one monitor in Connecticut recording a preliminary 2017 design value of 83 parts per billion (ppb).

3
The EPA had not yet issued final designations at the time the petition was submitted. On April 30, 2018, the EPA designated New York-Northern New Jersey-Long Island, NY-NJ-CT area (NYMA) as a Moderate nonattainment area for the 2015 ozone NAAQS. 83 FR 25776 (June 4, 2018).

The New York petition alleges that emissions from numerous, named upwind sources significantly contribute to nonattainment and interfere with maintenance of the 2008 and 2015 8-hour ozone NAAQS in New York based on two arguments. First, the petition alleges that the EPA's 2017 contribution modeling conducted in support of the EPA's Cross-State Air Pollution Rule (CSAPR) Update
4

shows that the nine states in which these sources are located contribute 1 percent or more of the 2008 8-hour ozone NAAQS (or 0.75 ppb or more) to ozone concentrations in New York. Second, the petition describes a study that allegedly found that air transported into Chautauqua County on the worst air quality days results in maximum daily ozone concentrations that, on average, are within 2 ppb of the 2015 ozone NAAQS and often exceed the standard of 70 ppb.
5

4
81 FR 74504 (October 26, 2016).

5
The petition discusses the results of a study titled the “Dunkirk Monitor Transport Study,” which presents an analysis of back-trajectories used to single out interstate airflow on “design days,” which the petition defines as days considered in the calculation of the design values. The subject days include the 4 days in each year from 2013 to 2017 with the largest daily maximum 8-hour ozone concentrations at the Dunkirk monitoring site in Chautauqua County, New York. The Dunkirk monitoring site is the design value monitoring site in Chautauqua County (
i.e.,
the site with the highest design value in the county).

When identifying what constitutes significant ozone contributions, the petition considers the highest emitting facilities (
i.e.,
EGU and non-EGU facilities emitting, or projected to emit, 400 tons per year or more of NO
X
) from the named states and asserts that these facilities are expected to have the

greatest impact on the ability of the NYMA and Chautauqua County to attain and maintain the 2008 and 2015 NAAQS.
6

The petition uses NY DEC generated air quality modeling data to show single-day, 8-hour average impacts from the group of 400 ton-per-year sources identified in any individual state of up to 6.34 ppb in Chautauqua County and 4.97 ppb in the New York portion of the NYMA nonattainment area.
7

The petition asserts that instances in which the maximum impact from an individual state's total combined 400 ton-per-year sources exceeds 0.75 ppb at a particular monitor indicate significant contribution to nonattainment or interference with maintenance of the 2008 ozone NAAQS. The petition further asserts that impacts above 0.70 ppb indicate significant contribution to nonattainment or interference with maintenance of the 2015 ozone NAAQS. NY DEC used its own independent modeling to support the assertions in their CAA section 126(b) petition because the State “has significant concerns” about the assumptions and results of the EPA's recently released 2023 air quality modeling and its applicability to the CAA section 126(b) petition process.
8

The petition takes particular issue with the EPA's expectation that uncontrolled EGUs will greatly reduce their emissions rates in the absence of unit-level enforceable limits and expresses the additional concern that the EPA may have underestimated the ozone concentration results for monitoring sites located near significant water bodies based on the treatment of model cells containing a land/water interface. The petition also asserts that modeling of 2023 is insufficient to support good neighbor state implementation plans (SIPs) and cannot be used to support a review of New York's petition because CAA section 126(c) explicitly states that compliance must be met “in no case later than three years after the date of [a CAA section 126(b)] finding,” and 2023 is more than 3 years after the deadline by which the EPA must act on the NY DEC petition.

6
The petition identifies which facilities emit 400 tons per year of more of NO
X
based on 2017 EGU projections by the Mid-Atlantic Regional Air Management Association. The petition also identifies non-EGU sources emitting greater than 400 tons of NO
X
in the 2014 National Emissions Inventory.

7
The petition provides additional detail regarding the modeling methodology. Specifically, the petition notes that NY DEC used version 5.0.2 of the Community Multiscale Air Quality model with the EPA's Weather Research Forecast (WRF) 2011 meteorological data to model hourly ozone concentrations during the period May 18 to July 30 for a 2017 “baseline” scenario and additional state-by-state “control” modeling scenarios in which emissions from the named sources in a given state were set to zero. The petition explains that NY DEC then used the modeled concentrations to calculate the 8-hour daily maximum average (MDA8) in each grid cell on each day of the modeling period for each modeled scenario. The difference in MDA8 concentrations between the 2017 baseline and each state zero-out run was used to represent the contributions on each day. The NY DEC then selected the largest single-day contribution from among the highest ozone concentration days to support their analysis of contributions relative to a 1-percent-of-the-NAAQS threshold.

8

See
the EPA's October 27, 2017 memorandum titled, “Supplemental 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)” that provided future year ozone design values for monitoring sites in the U.S. based on updated air quality modeling (for 2023) and monitoring data.

After asserting that the identified sources within the named upwind states significantly contribute to nonattainment or interfere with maintenance of the 2008 and 2015 ozone NAAQS in New York, the petition further asserts that these named sources can reasonably be retrofitted with control equipment or can operate existing controls more frequently to reduce NO
X
emissions. The petition requests that the EPA establish permanent and enforceable emissions limitations for the named sources at levels designed to prevent them from significantly contributing to nonattainment or interfering with maintenance in New York State. Specifically, the petition requests that the named sources be subject to emissions limits consistent with Reasonably Available Control Technology (RACT) as defined by New York State, which bases its presumptive limits and facility-specific control analyses on a standard of $5,000 per ton of NO
X
reduced. The petition acknowledges that some of the facilities identified in the petition may already operate with a NO
X
emissions rate similar to New York's RACT limits. Nonetheless, the petition asks that the EPA establish enforceable daily emissions limits during the ozone season to require these sources to continue to operate at these rates in the future. The petition claims that enforceable emissions limits would prevent emissions controls from being turned off, which the petition asserts occurs when the sources in the State are collectively emitting well below their seasonal CSAPR budgets. Section III.D of the proposal provides more detail regarding the content of the New York CAA section 126(b) petition.

After receiving New York's CAA section 126(b) petition in March of 2018, and consistent with CAA section 307(d)(10), the EPA determined that the 60-day period for responding to New York's petition was insufficient for the EPA to act on the petition. On May 11, 2018, the EPA published a document extending the deadline for acting on New York's CAA section 126(b) petition to November 9, 2018.
9

That document is in the docket for this rulemaking.

9
83 FR 21909 (May 11, 2018).

C. Summary of the EPA's May 6, 2019, Proposal

In Section IV of the proposal, the EPA explained its basis for proposing to deny the CAA section 126(b) petition from New York. Given that ozone is a regional pollutant and that the EPA had recently evaluated regional ozone pollution in two recent rulemakings—the CSAPR Update
10

and the Determination Regarding Good Neighbor Obligations for the 2008 Ozone National Ambient Air Quality Standard
11

(the Determination Rule)—the EPA proposed to evaluate New York's CAA section 126(b) petition consistent with the same four-step interstate transport framework (
see
Section II.C.1 of this action) that the EPA has used in previous regulatory actions to evaluate regional ozone transport problems.

10
81 FR 74504 (October 26, 2016).

11
83 FR 65878 (December 21, 2018).

The EPA identified multiple bases for the proposed denial. The EPA noted that the Agency's historical approach to evaluating CAA section 126(b) petitions first looks at whether a petition independently identifies or establishes a technical basis for the requested CAA section 126(b) finding. 84 FR 22797. In this regard, the Agency proposed to find that several aspects of New York's analyses are insufficient to support New York's conclusion that the sources named in the petitions emit or would emit in violation of the good neighbor provision. First, considering step 1 of the four-step interstate transport framework, the EPA proposed to find that New York's petition does not provide sufficient information to demonstrate that there is a current or expected future downwind nonattainment or maintenance problem in Chautauqua County with respect to either the 2008 or the 2015 ozone NAAQS.
Id.
at 22800. Similarly, with respect to the NYMA, the EPA proposed to find, at step 1, that the New York petition does not provide sufficient information to indicate that there will be a future nonattainment or maintenance problem with respect to the 2008 ozone NAAQS.
Id.
at 22800-01. Second, considering step 3 of the four-step interstate transport framework, the EPA proposed to find that material

elements in New York's analyses are technically deficient, such that the EPA cannot conclude that any source or group of sources in any of the named states will significantly contribute to nonattainment or interfere with maintenance in Chautauqua County or the NYMA relative to the 2008 and 2015 ozone NAAQS.
Id.
at 22802.

The EPA further proposed to rely on its own independent analysis to evaluate the requested CAA section 126(b) findings at step 1 considering available air quality monitoring and modeling data.
Id.
at 22800. The EPA proposed to find that its independent analysis provides no basis to conclude that Chautauqua County will have an air quality problem relative to either the 2008 or the 2015 ozone NAAQS. The EPA explained that the 2015-2017 design value in Chautauqua County is 68 ppb, which is below the level of both the 2008 and 2015 ozone NAAQS.
12

Furthermore, the EPA indicated that it had recently finalized a determination that the Jamestown, New York Marginal nonattainment area (Chautauqua County) has attained the 2008 ozone NAAQS.
13

Additionally, Section IV.B of the proposal explained that the EPA's examination in the Determination Rule of the 2023 projected design values for Chautauqua County indicates that this area is not projected to be in nonattainment or have a maintenance problem in 2023 for the 2008 ozone NAAQS. The EPA's air quality modeling supporting the Determination Rule also indicates that the monitor in Chautauqua County is expected to continue to both attain and maintain the 2015 ozone NAAQS standard in 2023, with an average 2023 design value of 58.5 ppb and a maximum 2023 design value of 60.7 ppb.
14

12
The 2015-2017 design value for Chautauqua County in the “Jamestown-Dunkirk-Fredonia, NY CBSA” at AQS site 360130006 is 68 ppb. Available at
https://www.epa.gov/sites/production/files/2018-07/ozone_designvalues_20152017_final_07_24_18.xlsx.

13

See
Approval and Promulgation of Air Quality Implementation Plans; New York; Determination of Attainment of the 2008 8-Hour Ozone National Ambient Air Quality Standard for the Jamestown, New York Marginal Nonattainment Area, 83 FR 49492 (October 2, 2018).

14

See
2023 design values for AQS site 360130006 in spreadsheet released with the EPA's March 2018 memorandum. Available at
https://www.epa.gov/sites/production/files/2018-05/updated_2023_modeling_dvs_collective_contributions.xlsx.

The EPA also proposed to find that its independent analysis, conducted to support the Determination Rule, provides no basis to conclude that the NYMA will have a future air quality problem relative to the 2008 ozone NAAQS. The EPA's examination of the 2023 projected design values for the NYMA indicates that this area is not projected to be in nonattainment or have a maintenance problem in 2023 for the 2008 ozone NAAQS. However, the modeling indicates that the NYMA is projected to be in nonattainment in 2023 with respect to the 2015 ozone NAAQS.

As noted previously, considering step 3 of the four-step interstate transport framework, the EPA proposed to find that material elements in New York's analyses are technically deficient, such that the EPA cannot conclude that any source or group of sources in any of the named states will significantly contribute to nonattainment or interfere with maintenance in Chautauqua County or the NYMA relative to the 2008 and 2015 ozone NAAQS. As discussed in Section IV.B of the proposal, the EPA did not independently conduct a regional step 3 analysis for any sources with respect to the 2015 ozone NAAQS because the EPA interprets CAA section 126(b) as placing the burden on the petitioner to establish a technical basis for the specific finding requested, and, unlike the step 1 analysis, the EPA lacked information and analysis on which it could rely for such an independent step 3 analysis.

II. Background and Legal Authority

This section of the notification discusses background and legal authority relevant to this action beginning with an overview of ozone formation and interstate transport in Section II.A. Section II.B of this notification describes the key statutory provisions under both CAA sections 126 and 110(a)(2)(D)(i)(I), including the relationship between the good neighbor provision and CAA section 126(b). Section II.C summarizes the EPA's historical approach to addressing the interstate transport of ozone under the good neighbor provision to include a description of the four-step interstate transport framework and the EPA's prior regional rulemakings.

A. Ground-Level Ozone and the Interstate Transport of Ozone

On March 12, 2008, the EPA promulgated a revision to the ground-level ozone NAAQS, lowering both the primary and secondary standards to 75 ppb.
15

On October 1, 2015, the EPA further revised the ground-level ozone NAAQS to 70 ppb.
16

15

See
National Ambient Air Quality Standards for Ozone, Final Rule, 73 FR 16436 (March 27, 2008).

16

See
National Ambient Air Quality Standards for Ozone, Final Rule, 80 FR 65292 (October 26, 2015).

As discussed in Section III.A of the proposal, ground-level ozone is not emitted directly into the air but is a secondary air pollutant created by chemical reactions between ozone precursors, chiefly NO
X
and non-methane volatile organic compounds (VOCs), in the presence of sunlight. Emissions from mobile sources, EGUs, industrial facilities, gasoline vapors, and chemical solvents are some of the major anthropogenic sources of ozone precursors. These precursor emissions can be transported downwind directly or, after transformation in the atmosphere, as ozone. Studies have established that ozone formation, atmospheric residence, and transport can occur on a regional scale (
i.e.,
across hundreds of miles) over much of the eastern United States. Thus, in any given location, ozone pollution levels are affected by a combination of local emissions and emissions from upwind sources. Numerous observational studies have demonstrated the transport of ozone and its precursors and the impact of upwind emissions on high concentrations of ozone pollution.
17

For further discussion of ozone-formation chemistry and health effects,
see
the National Ambient Air Quality Standards for Ozone, Final Rule, 80 FR 65292 (October 26, 2015). For further discussion of the regional nature of interstate transport of ozone pollution
see
the Determination Rule, 83 FR 65879-80 (December 21, 2018).

17
For example, Bergin, M.S. et al. (2007). Regional air quality: local and interstate impacts of NO
X
and SO
2
emissions on ozone and fine particulate matter in the eastern United States. Environmental Sci & Tech. 41: 4677-4689.

B. CAA Sections 110 and 126

CAA sections 126 and 110(a)(2)(D)(i) provide the statutory authority for this action. Section 126(b) of the CAA provides, among other things, that any state or political subdivision may petition the Administrator of the EPA to find that any major source or group of stationary sources in an upwind state emits or would emit any air pollutant in violation of the prohibition of CAA section 110(a)(2)(D)(i), referred to as the good neighbor provision of the Act.
18

Petitions submitted pursuant to this section are commonly referred to as CAA section 126(b) petitions. Similarly, findings by the Administrator, pursuant to this section, that a source or group of

sources emits air pollutants in violation of the CAA section 110(a)(2)(D)(i) prohibition are commonly referred to as CAA section 126(b) findings.

18
The text of CAA section 126 as codified in the U.S. Code cross-references CAA section 110(a)(2)(D)(ii) instead of CAA section 110(a)(2)(D)(i). The courts have confirmed that this is a scrivener's error and that Congress instead intended to cross-reference CAA section 110(a)(2)(D)(i).
See Appalachian Power Co.
v.
EPA,
249 F.3d 1032, 1040-44 (D.C. Cir. 2001).

CAA section 126 explains the effect of a CAA section 126(b) finding and establishes the conditions under which continued operation of a source subject to such a finding may be permitted. Specifically, CAA section 126(c) provides that it is a violation of section 126 of the Act and of the applicable SIP: (1) For any major proposed new or modified source subject to a CAA section 126(b) finding to be constructed or operate in violation of the prohibition of CAA section 110(a)(2)(D)(i) or (2) for any major existing source for which such a finding has been made to stay in operation more than 3 months after the date of the finding. The statute, however, also gives the Administrator discretion to permit the continued operation of a source beyond 3 months if the source complies with emissions limitations and compliance schedules provided by the EPA to bring about compliance with the requirements contained in CAA sections 110(a)(2)(D)(i) and 126 as expeditiously as practicable, but in any event no later than 3 years from the date of the finding.

Section 110(a)(2)(D)(i) of the CAA requires states to prohibit certain emissions from in-state sources if such emissions impact the air quality in downwind states. Specifically, CAA sections 110(a)(1) and 110(a)(2)(D)(i)(I) require all states, within 3 years of promulgation of a new or revised NAAQS, to submit SIPs that contain adequate provisions prohibiting any source or other type of emissions activity within the state from emitting any air pollutant in amounts which will contribute significantly to nonattainment in, or interfere with maintenance by, any other state with respect to that NAAQS. As described further in Section II.C.2, the EPA has developed several regional rulemakings to address the requirements of CAA section 110(a)(2)(D)(i)(I) for the various ozone NAAQS. The EPA's most recent rulemaking, the Determination Rule, finalized a determination that the existing CSAPR Update fully addresses certain states' interstate transport obligations under CAA section 110(a)(2)(D)(i)(I) for the 2008 ozone NAAQS. 83 FR 65878 (December 21, 2018).

Section 110(a)(2)(D)(ii) of the CAA further requires SIPs to contain adequate provisions ensuring compliance with the applicable requirements of,
inter alia,
CAA section 126. Thus, where the EPA has made a finding pursuant to CAA section 126(b), this provision requires states to revise their SIPs to adopt any emissions limitations and compliance schedules provided by the EPA under CAA section 126(c).

C. The EPA's Historical Approach To Addressing Interstate Transport of Ozone Under the Good Neighbor Provision

Given that formation, atmospheric residence, and transport of ozone can occur on a regional scale (
i.e.,
across hundreds of miles) and that many separate areas across the eastern U.S. have struggled to attain and maintain the NAAQS, the EPA has historically addressed the interstate transport of ozone pursuant to the good neighbor provision by promulgating rulemakings that addressed significant contribution and interference with maintenance through regional trading programs to reduce NO
X
emissions. Each of these rulemakings followed a similar four-step interstate transport framework to evaluate and address the extent of the ozone transport problem (
i.e.,
the breadth of downwind ozone problems and the contributions from upwind states) and, ultimately, to find that downwind states' problems attaining and maintaining the ozone NAAQS result from an interconnected system of transported pollution emitted by multiple upwind sources located in different upwind states combined with downwind (
i.e.,
locally generated) ozone.

1. Description of the Four-Step Interstate Transport Framework

Through the development and implementation of several previous rulemakings,
19

the EPA established the following four-step interstate transport framework to address the requirements of the good neighbor provision for regional pollutants such as ozone and fine particulate matter (PM
2.5
):

19

See
Finding of Significant Contribution and Rulemaking for Certain States in the Ozone Transport Assessment Group Region for Purposes of Reducing Regional Transport of Ozone (also known as the NO
X
SIP Call), 63 FR 57356 (October 27, 1998); Clean Air Interstate Rule (CAIR) Final Rule, 70 FR 25162 (May 12, 2005); CSAPR Final Rule, 76 FR 48208 (August 8, 2011); CSAPR Update Final Rule, 81 FR 74504 (October 26, 2016); Determination Rule, 83 FR 65878 (December 21, 2018).

(1)
Identify downwind receptors that are expected to have problems attaining or maintaining the NAAQS.
The EPA historically identified downwind areas with air quality problems, referred to as receptors, using air quality modeling projections for a future analytic year and, where appropriate, considering monitored air quality data.

(2)
Determine which upwind states are linked to these identified downwind air quality problems and thus warrant further analysis to determine whether their emissions violate the good neighbor provision.
In the EPA's most recent transport rulemakings for the 1997 and 2008 ozone NAAQS, as well as the 1997 and 2006 PM
2.5
NAAQS, the Agency identified such upwind states to be those modeled to contribute at or above an air quality threshold relative to the applicable NAAQS.

(3)
For states linked to downwind air quality problems, identify upwind emissions (if any) on a statewide basis that will significantly contribute to nonattainment or interfere with maintenance of a standard at a receptor in another state.
In the EPA's prior rulemakings for ozone and PM
2.5
, the Agency identified and apportioned emissions reduction responsibility among multiple upwind states linked to downwind air quality problems by identifying a uniform level of control stringency for certain sources in the state based on cost and air quality factors evaluated in a multi-factor test.

(4)
For upwind states that are found to have emissions that will significantly contribute to nonattainment or interfere with maintenance of the NAAQS downwind, implement the necessary emissions reductions within the state.
When the EPA has promulgated federal implementation plans (FIPs) addressing the good neighbor provision for ozone and PM
2.5
NAAQS in prior transport rulemakings, the EPA has typically required affected sources in upwind states to participate in allowance trading programs to achieve the necessary emissions reductions.
20

In addition, the EPA has also offered states the opportunity to participate in comparable EPA-operated allowance trading programs to achieve the necessary emissions reductions through SIPs.

20
While the EPA has chosen to implement emissions reductions through allowance trading programs for states found to have a downwind impact, upwind states can choose to submit a SIP that implements such reductions through other enforceable mechanisms that meet the requirements of the good neighbor provision, such as the enforceable mechanisms that the petitioner apparently favors in its petition.

Using the four-step framework to evaluate a particular interstate transport problem allows the EPA to determine whether upwind states actually contribute to a downwind air quality problem, whether and which sources can be cost-effectively controlled to address that downwind air quality

problem, what level of emissions should be eliminated to address the downwind air quality problem (and thus should be considered “significant”), and the means of implementing corresponding emissions limits (
i.e.,
source-specific rates or statewide emissions budgets in a limited regional allowance trading program). The outcome of this assessment varies based on the scope of the air quality problem, the availability and cost of controls at sources in upwind states, and the estimated impact of upwind emissions reductions on downwind ozone concentrations.

2. Prior Regional Rulemakings Under the Good Neighbor Provision

The EPA's first regional interstate transport rulemaking, the NO
X
SIP Call, addressed the 1979 ozone NAAQS. 63 FR 57356 (October 27, 1998).
21

The NO
X
SIP Call was the result of the analytic work and recommendations of the Ozone Transport Assessment Group, which was organized and led by states in consultation with the EPA and other stakeholders. The EPA used this collaboratively developed analysis to conclude in the NO
X
SIP Call that “[t]he fact that virtually every nonattainment problem is caused by numerous sources over a wide geographic area is a factor suggesting that the solution to the problem is the implementation over a wide area of controls on many sources, each of which may have a small or unmeasurable ambient impact by itself.” 63 FR 57356, 57377 (October 27, 1998). The NO
X
SIP Call promulgated statewide emissions budgets and required upwind states to adopt SIPs that would decrease their NO
X
emissions to meet these budgets, thereby prohibiting the emissions that significantly contribute to nonattainment or interfere with maintenance of the ozone NAAQS in downwind states. The EPA also promulgated a model rule for a regional allowance trading program called the NO
X
Budget Trading Program that states could adopt in their SIPs as a mechanism to achieve some or all required emissions reductions. All jurisdictions covered by the NO
X
SIP Call ultimately chose to adopt the NO
X
Budget Trading Program into their SIPs. The NO
X
SIP Call was upheld by the U.S. Court of Appeals for the District of Columbia Circuit (D.C. Circuit) in all pertinent respects.
See Michigan
v.
EPA,
213 F.3d 663 (2000).

21
As originally promulgated, the NO
X
SIP Call also addressed good neighbor obligations under the 1997 8-hour ozone NAAQS, but the EPA subsequently stayed the rule's provisions with respect to that standard. 65 FR 56245 (September 18, 2000). The EPA recently finalized an action rescinding the findings of good neighbor obligations with respect to the 1997 ozone NAAQS as a basis for the NO
X
SIP Call. 84 FR 8422 (March 8, 2019).

In coordination with the NO
X
SIP Call rulemaking under CAA section 110(a)(2)(D)(i)(I), the EPA also addressed several pending CAA section 126(b) petitions submitted by eight northeastern states regarding the same air quality issues addressed by the NO
X
SIP Call, specifically interstate ozone transport for the 1979 ozone NAAQS. These CAA section 126(b) petitions asked the EPA to find that ozone precursor emissions from numerous sources located in 30 states and the District of Columbia had adverse air quality impacts on the petitioning downwind states. Half of the petitioning states (
i.e.,
Connecticut, Maine, New York, and Pennsylvania) requested an allowance trading program to reduce NO
X
emissions and remedy regional interstate ozone transport. 63 FR 56297 (October 21, 1998). Based on analysis conducted for the NO
X
SIP Call regarding upwind state impacts on downwind air quality, the EPA, in May 1999, made technical determinations regarding the claims in the petitions, but did not at that time make the CAA section 126(b) findings requested by the petitions. 64 FR 28250 (May 25, 1999). In making these technical determinations, the EPA concluded that the NO
X
SIP Call would fully address and remediate the claims raised in these petitions and that the EPA would, therefore, not need to take separate action to remedy any potential violations of the CAA section 110(a)(2)(D)(i) prohibition. 64 FR 28252. However, subsequent litigation resulted in a judicial stay of the NO
X
SIP Call and led the EPA to “de-link” the CAA section 126(b) petition response from the NO
X
SIP Call. The EPA made final CAA section 126(b) findings for 12 states named in the petitions and the District of Columbia. The EPA found that sources in these states emitted in violation of the prohibition in the good neighbor provision with respect to the 1979 ozone NAAQS based on the affirmative technical determinations made in the May 1999 rulemaking. To remedy the violation under CAA section 126(c), the EPA required affected sources in the upwind states to participate in a regional allowance trading program whose requirements were designed to be interchangeable with the requirements of the optional NO
X
Budget Trading Program model rule provided under the NO
X
SIP Call. 65 FR 2674 (January 18, 2000). The EPA's action on these CAA section 126(b) petitions was upheld by the D.C. Circuit.
See Appalachian Power Co.
v.
EPA,
249 F.3d 1032 (D.C. Cir. 2001).

The EPA next promulgated the Clean Air Interstate Rule (CAIR), 70 FR 25162 (May 12, 2005), to address interstate transport under the good neighbor provision with respect to the 1997 ozone NAAQS, as well as the 1997 PM
2.5
NAAQS. 70 FR 25172. The EPA adopted the same approach for quantifying the level of states' significant contribution to downwind nonattainment in CAIR as it used in the NO
X
SIP Call, based on the determination in the NO
X
SIP Call that downwind ozone nonattainment is due to the impact of emissions from numerous upwind sources and states. 70 FR 25162, 25172 (May 12, 2005). The EPA explained that “[t]ypically, two or more States contribute transported pollution to a single downwind area, so that the `collective contribution' is much larger than the contribution of any single State.” 70 FR 25186. CAIR included two distinct regulatory processes: (1) A rulemaking to define significant contribution (
i.e.,
the emissions reduction obligation) under the good neighbor provision and provide for submission of SIPs eliminating that contribution, 70 FR 25162 (May 12, 2005); and (2) a rulemaking to promulgate, where necessary, FIPs imposing emissions limitations in the event states did not submit SIPs. 71 FR 25328 (April 28, 2006). The FIPs required EGUs in affected states to participate in regional allowance trading programs, which replaced the previous NO
X
Budget Trading Program.

In conjunction with the second CAIR rulemaking, which promulgated backstop FIPs, the EPA acted on a CAA section 126(b) petition received from the State of North Carolina on March 19, 2004, seeking a finding that large EGUs located in 13 states were significantly contributing to nonattainment and/or interfering with maintenance of the 1997 ozone NAAQS and the 1997 PM
2.5
NAAQS in North Carolina. Citing the analyses conducted to support the promulgation of CAIR, the EPA denied North Carolina's CAA section 126(b) petition in full based on determinations either that the named states were not adversely impacting downwind air quality in violation of the good neighbor provision, or that such impacts were fully remedied by implementation of the emissions reductions required by the CAIR FIPs. 71 FR 25328, 25330 (April 28, 2006).

The D.C. Circuit found that the EPA's approach to CAA section 110(a)(2)(D)(i)(I) in CAIR was “fundamentally flawed” in several

respects, and the rule was remanded in July 2008 with the instruction that the EPA replace the rule “from the ground up.”
North Carolina
v.
EPA,
531 F.3d 896, 929 (D.C. Cir.), modified on reh'g, 550 F.3d 1176 (D.C. Cir. 2008). The decision concluded the EPA's analysis and compliance mechanisms did not address all elements required by the statute. The EPA's separate action denying North Carolina's CAA section 126(b) petition was not challenged.

On August 8, 2011, the EPA promulgated CSAPR to replace CAIR. 76 FR 48208 (August 8, 2011). CSAPR addressed the same (1997) ozone and PM
2.5
NAAQS as CAIR and additionally addressed interstate transport for the 2006 PM
2.5
NAAQS by requiring 28 states to reduce sulfur dioxide (SO
2
) emissions, annual NO
X
emissions, and/or ozone season NO
X
emissions that would significantly contribute to other states' nonattainment or interfere with other states' ability to maintain these air quality standards. Consistent with prior determinations made in the NO
X
SIP Call and CAIR, the EPA again found that emissions from sources in multiple upwind states contributed to ozone nonattainment in multiple downwind states. Specifically, the EPA found “that the total `collective contribution' from upwind sources represents a large portion of PM
2.5
and ozone at downwind locations and that the total amount of transport is composed of the individual contribution from numerous upwind states.” 76 FR 48237. Accordingly, the EPA conducted a regional analysis, calculated emissions budgets for affected states, and required EGUs in these states to participate in new regional allowance trading programs to reduce statewide emissions levels.
22

CSAPR was subject to nearly 4 years of litigation. Ultimately, the Supreme Court upheld the EPA's approach to calculating emissions reduction obligations and apportioning upwind state responsibility under the good neighbor provision, but also held that the EPA was precluded from requiring more emissions reductions than necessary to address downwind air quality problems, or “over-controlling” upwind state emissions.
See EPA
v.
EME Homer City Generation, L.P.,
572 U.S. 489, 521-22 (2014) (
EME Homer City
).
23

22
The CSAPR trading programs included assurance provisions to ensure that emissions are reduced within each individual state, in accordance with
North Carolina,
531 F.3d at 907-08 (holding the EPA must require elimination of emissions from each upwind state that contribute significantly to nonattainment and interfere with maintenance in downwind areas). Those provisions were also included in the CSAPR Update and took effect with the 2017 CSAPR compliance periods.

23
On remand from the Supreme Court, the D.C. Circuit further affirmed various aspects of the CSAPR, while remanding the rule without vacatur for reconsideration of certain states' emissions budgets where it found those budgets may over-control emissions beyond what was necessary to address the good neighbor requirements.
EME Homer City Generation, L.P.
v.
EPA,
795 F.3d 118 (2015) (
EME Homer City II
). The EPA addressed the remand in several rulemaking actions in 2016 and 2017.

In 2016, the EPA promulgated the CSAPR Update to address the good neighbor provision requirements for the 2008 ozone NAAQS. 81 FR 74504 (October 26, 2016). The CSAPR Update built upon previous regulatory efforts to address the collective contributions of ozone pollution from 22 states in the eastern U.S. to widespread downwind air quality problems. As with previous rulemakings, the EPA evaluated the nature (
i.e.,
breadth and interconnectedness) of the ozone problem and NO
X
reduction potential from EGUs, including essentially all the EGUs at the facilities named in the New York CAA section 126(b) petition.
24

In the CSAPR Update, the EPA quantified emissions reduction obligations for each state based on an analysis of control strategies that could be implemented by the upcoming 2017 ozone season, which coincided with the (then) upcoming 2018 Moderate area attainment date. The EPA implemented those emissions reductions through FIPs which required EGUs in affected states to participate in a regional allowance trading program to further reduce statewide NO
X
emissions levels. The CSAPR Update is subject to pending legal challenges in the D.C. Circuit.
Wisconsin
v.
EPA,
No. 16-1406 (D.C. Cir. argued October 3, 2018).

24
The EPA uses the language “
essentially all
the EGUs at the facilities named . . . .” (emphasis added) to clarify that the New York petition identifies sources at the facility, rather than at the unit, level. The CSAPR Update looked at unit-level data and included all fossil-fuel-fired boiler or combustion turbine EGUs with a capacity (electrical output) greater than 25 megawatts (MW).
See
81 FR 74563 (October 26, 2016).

At the time the EPA finalized the CSAPR Update in 2016, the EPA was unable to determine whether the rule fully resolved good neighbor obligations with respect to the 2008 ozone NAAQS for most (
i.e.,
21) of the States subject to that action, including those addressed in New York's petition (
i.e.,
Illinois, Indiana, Kentucky, Maryland, Michigan, Ohio, Pennsylvania, Virginia and West Virginia). The EPA stated that, based on its analysis of 2017 air quality at that time, the emissions reductions required by the rule “may not be all that is needed” to address transported emissions.
25

81 FR 74521-22 (October 26, 2016). The information available at that time suggested that downwind air quality problems would remain in 2017 after implementation of the CSAPR Update and that upwind states continued to be linked to those downwind problems at or above the 1 percent threshold used at step 2 of the EPA's analysis. However, in the CSAPR Update, the EPA could not determine whether, in step 3 of the four-step interstate transport framework, the EPA had quantified all emissions reductions that may be considered cost-effective because the rule did not evaluate non-EGU ozone season NO
X
reductions or further EGU control strategies (
i.e.,
the implementation of new post-combustion controls) that may be achievable on timeframes extending beyond the 2017 analytic year used in the EPA's analysis. The Agency recognized that completing such an analysis could extend the timeframe for action and prioritized the substantial short-term emissions reductions achievable for the 2017 ozone season.
See
81 FR 74521 for additional details.

25
The EPA determined that the emissions reductions required by the CSAPR Update satisfied the full scope of the good neighbor obligation for Tennessee with respect to the 2008 ozone NAAQS. 81 FR 74551-52 (October 26, 2016).

On December 6, 2018, the EPA finalized a determination that, based on the latest available emissions inventory and air quality modeling data for a 2023 analytic year, the CSAPR Update fully addresses the good neighbor provision requirements for the 2008 ozone NAAQS for 20 eastern states (among the 22) previously addressed in the CSAPR Update. 83 FR 65878 (December 21, 2018). The EPA's Determination Rule applied the four-step interstate transport framework but did not move beyond an analysis at step 1, because the EPA found that there would be no remaining nonattainment or maintenance receptors for the 2008 ozone NAAQS in the eastern U.S. in 2023. Therefore, with the CSAPR Update fully implemented, the EPA finalized in the Determination Rule a finding that the 20 states addressed by that action (including eight of the nine states named in New York's petition) will not contribute significantly to nonattainment in, or interfere with maintenance by, any other state regarding the 2008 ozone NAAQS. The EPA had already determined that the remaining two states would have no remaining good neighbor obligation for the 2008 ozone NAAQS—one in the CSAPR Update (Tennessee), 81 FR 74540 (October 26, 2016), and the other in a separate SIP approval (Kentucky,

the ninth state named in New York's petition), 83 FR 33730 (July 17, 2018), that relied on the same air quality modeling used in the Determination Rule. The Determination Rule is subject to pending legal challenges in the D.C. Circuit.
New York
v.
EPA,
No. 19-1019 (D.C. Cir.).

Most recently, the EPA acted on six CAA section 126(b) petitions pertaining to the 2008 and 2015 ozone NAAQS submitted by the States of Connecticut, Delaware, and Maryland regarding various sources in five upwind states. In denying the petitions, the EPA applied the same four-step interstate transport framework used in prior rulemakings and relied on analysis and determinations made in the CSAPR Update for purposes of evaluating the good neighbor obligations with respect to the 2008 ozone NAAQS. 83 FR 16064 (April 13, 2018) (Connecticut) 83 FR 50444 (October 5, 2018) (Delaware and Maryland).
26

The EPA found that the downwind areas were not projected to have problems attaining or maintaining the NAAQS (step 1) and/or that the petition failed to identify cost-effective emissions reductions for the affected sources (step 3), particularly where enforceable emissions limits had already been implemented for certain sources in the form of state-wide emissions budgets and, thus, the EPA already had addressed their significant contribution or interference with maintenance for those sources.

26
The EPA's denial of the Delaware and Maryland petitions is subject to pending legal challenges in the D.C. Circuit.
Maryland
v.
EPA,
No. 18-1285 (D.C. Cir. filed October 15, 2018).

III. The EPA's Final Response to the CAA Section 126(b) Petition From New York

The EPA is finalizing a denial of the CAA section 126(b) petition from New York. Section III.A of this notification describes the reasonableness of applying the four-step interstate transport framework as the standard of review in evaluating New York's CAA section 126(b) petition. Section III.B discusses the EPA's general standard of review of CAA section 126(b) petitions. Section III.C describes the EPA's determination that New York has not demonstrated that the sources named in its petition emit or would emit in violation of the good neighbor provision such that they will significantly contribute to nonattainment or interfere with maintenance of the 2008 or 2015 ozone NAAQS in New York. Where the EPA has currently available information to inform an independent analysis of New York's petition, we also present this information in Section III.C. In Section III, generally, and in the RTC document included in the docket for this action, the Agency explains the rationale supporting its final action and provides its response to significant public comments on the proposed action.

A. Reasonableness of Applying the Four-Step Interstate Transport Framework for This Action

As discussed in Section II.C of this notification, the EPA has consistently analyzed ozone transport with the understanding that nonattainment and maintenance concerns result from the cumulative air quality impacts of contributions from numerous anthropogenic sources across several upwind states (as well as from within the downwind state). Consistent with this understanding, the EPA has historically evaluated ozone transport based, in part, on the relative contribution of all anthropogenic sources within a state, as measured against a screening threshold, and then identified particular source sectors and units for regulatory consideration.
27

This approach to evaluating ozone transport is reasonable because the statute's use of “significantly” as a modifier to “contribute” implies a relationship (
e.g.,
the impact a source or collection of sources has relative to other relevant sources of that pollutant). Therefore, although CAA section 126(b) allows downwind states to petition the EPA regarding specific sources or groups of sources that they believe are contributing to the downwind air quality problems, the EPA believes it is reasonable and appropriate to evaluate the emissions from sources named in a CAA section 126(b) petition in the context of all relevant anthropogenic sources of that pollutant to determine whether emissions from the named sources violate the good neighbor provision. In this way, the EPA can evaluate whether the petitioner has appropriately identified the source or group of sources that should be regulated.

27
The EPA has used cost as a factor in its multi-factor approach for quantifying significant contribution from multiple contributing states. Cost is used in a relative (
i.e.,
least-cost abatement) approach that also requires examining individual source impact and reduction potential in the context of the larger universe of contributors.

The EPA notes that the four-step framework provides a logical, consistent and systematic approach for addressing interstate transport for a variety of criteria pollutants under a broad array of national, regional and local scenarios. Consequently, the EPA finds it reasonable to apply the same four-step interstate transport framework used to evaluate regional ozone transport under the good neighbor provision in considering a CAA section 126(b) petition addressing the impacts of individual sources on downwind attainment and maintenance of the ozone NAAQS. As the four-step interstate transport framework is applied to evaluate a particular interstate transport problem, the EPA can determine whether upwind sources are actually contributing to a downwind air quality problem; whether and which sources can be cost effectively controlled relative to that downwind air quality problem; what level of emissions should be eliminated to address the downwind air quality problem and the means of implementing corresponding emissions limits (
i.e.,
source-specific rates, or statewide emissions budgets in a limited regional allowance trading program). The outcome of this assessment will vary based on the scope of the air quality problem, the availably and cost of controls at sources in upwind states and the relative impact of upwind emissions reductions on downwind ozone concentrations.

The complexity of atmospheric chemistry and nature of ozone transport also demonstrate the appropriateness of applying the four-step interstate transport framework in considering a CAA section 126(b) petition. As a result of this complexity, including domestic and international as well as anthropogenic and background contributions to ozone and its precursors, it is less likely that a single source is entirely responsible for impacts to a downwind area. Thus, a determination regarding whether this impact is sufficient to significantly contribute to nonattainment or interfere with maintenance of the NAAQS—in light of other anthropogenic emissions sources impacting a downwind area—is necessarily more complicated. The EPA therefore evaluates within step 3 of the framework whether upwind sources have emissions that significantly contribute to nonattainment or interfere with maintenance of the ozone NAAQS based on various control, cost and air quality factors, including the magnitude of emissions from upwind states, the amount of potential emissions reductions from upwind sources, the cost of those potential emissions reductions, and the potential air quality impacts of emissions reductions.
28

The

EPA believes it is reasonable to consider these factors whether evaluating ozone transport in the context of a good neighbor SIP under CAA section 110 or a CAA section 126(b) petition.

28
“We believe it is important to consider both [cost and air quality] factors because circumstances related to different downwind receptors can vary and consideration of multiple factors can help EPA appropriately identify each state's significant

contribution under different circumstances . . . . Using both air quality and cost factors allows EPA to consider the full range of circumstances and state-specific factors that affect the relationship between upwind emissions and downwind nonattainment and maintenance problems. For example, considering cost takes into account the extent to which existing plants are already controlled as well as the potential for, and relative difficulty of, additional emissions reductions. Therefore, EPA believes that it is appropriate to consider both cost and air quality metrics when quantifying each state's significant contribution.” Proposed Federal Implementation Plans To Reduce Interstate Transport of Fine Particulate Matter and Ozone, 75 FR 45210, 45271 (August 2, 2010) (CSAPR proposal) (describing potential disparities between upwind and downwind state contributions to identified air quality problems and between levels of controls between states).

For any analysis of a CAA section 126(b) petition regarding interstate transport of ozone, a regional pollutant with contribution from a variety of sources, the EPA reviews whether the particular sources identified by the petitioner should be controlled in light of the collective impact of emissions on air quality in the area, including emissions from other anthropogenic sources. Thus, review of the named sources in New York's petition provides a starting point for the EPA's evaluation, but does not—as the commenters suggest—complete the evaluation to determine whether the named sources emit or would emit in violation of the good neighbor provision.

Several commenters assert that the EPA incorrectly applied the four-step interstate transport framework used to address CAA section 110(a)(2)(D)(i)(I) to the separate provision under CAA section 126(b). Specifically, one commenter states that the four-step interstate transport framework aligns with the planning requirements under CAA section 110(a)(2)(D)(i)(I) because it allows contribution to be apportioned by state boundaries particularly at step 2, which considers whether an upwind state is linked to the downwind air quality problem above an identified air quality threshold. The commenter explains that applying such a threshold allows the collective “significant contribution” from a group of sources located in multiple upwind states to be apportioned into “non-significant contributions” according to state boundaries. The commenter continues by stating that the provisions in CAA section 126 apply to source emissions regardless of state boundaries, thereby better reflecting the science of air pollution transport and allowing a state to petition for, were the EPA to grant the petition, the application of emissions reductions requirements to a group of stationary sources located in multiple upwind states.

A second commenter notes that the EPA's use of the four-step interstate transport within CAA section 126(b) does not facilitate the application of the CAA section 126(b) petition mechanism as intended, which the commenter articulates as including the use of such petitions and the EPA's action thereupon as a precise tool to control specific sources (
e.g.,
EGUs), potentially through the imposition of emissions limits including shorter averaging times. The commenter notes that the good neighbor provision, as the EPA has historically implemented it, relies on regional trading programs and robust emissions allowance pools, which do not guarantee control of emissions from nearby, upwind sources on high electric demand days that are most conducive to downwind ozone formulation.

The EPA disagrees with commenters who assert that its application of the four-step interstate transport framework used to address requirements under the good neighbor provision is not appropriate to address CAA section 126(b) petitions. While either CAA section 126(b) or CAA section 110(a)(2)(D)(i)(I) may be applied to address interstate transport, as discussed in Section III.B, the cross-reference in CAA section 126(b) to the prohibition in CAA section 110(a)(2)(D)(i) means that the same substantive standard is used to determine whether there is a violation under either section and, therefore, whether emissions should be prohibited in either a good neighbor SIP or in a finding under CAA section 126(b). Moreover, the EPA also believes its use of the four-step interstate transport framework to evaluate a CAA section 126(b) petition continues to be technically justified, especially as it applies to New York's petition addressing the impacts of hundreds of sources to alleged ozone nonattainment downwind.

As discussed earlier, the EPA agrees with commenters that ozone nonattainment problems result from the cumulative air quality impacts of relatively smaller contributions from numerous anthropogenic sources across several upwind states (as well as from within the downwind state). Thus, evaluating which upwind states and sources should be held responsible for addressing downwind nonattainment presents a “thorny causation problem.”
EME Homer City,
572 U.S. at 514. This is true whether the EPA is evaluating the problem in the context of reviewing a SIP or promulgating a FIP under CAA section 110(a)(2)(D)(i)(I) or in the context of evaluating a petition targeting individual sources under CAA section 126(b). The four-step interstate transport framework provides a reasonable approach to identifying which upwind states and sources among many should bear the responsibility for implementing emissions reductions to benefit downwind air quality.

Thus, the EPA disagrees with commenters asserting that application of a statewide air quality threshold at step 2 is inappropriate under CAA section 126(b). First, as discussed further in Section III.C of this notification, while the EPA is not taking a position regarding what air quality threshold is most appropriately applied with respect to the 2015 ozone NAAQS, the EPA agrees that its modeling shows that upwind states named in the petition are all linked to a projected air quality problem in the NYMA using the 1 percent threshold that the EPA has used in other recent rulemakings to evaluate step 2 linkages. Accordingly, although the EPA is not here deciding whether the 1 percent threshold is the only appropriate screening level that might be applied for good neighbor analysis for the 2015 ozone NAAQS in other contexts (such as the EPA's review of SIP submissions
29

addressing 2015 ozone NAAQS good neighbor obligations), the EPA has not proposed to deny the petition on the basis of any analysis at step 2, and the commenter's concern that the use of any statewide air quality threshold is ill-suited to a CAA section 126(b) petition is not raised in this action.

29

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 2018) (providing analysis to support potential use of a 1 ppb threshold in the development of good neighbor SIPs for the 2015 ozone NAAQS). Available at
https://www.epa.gov/sites/production/files/2018-09/documents/contrib_thresholds_transport_sip_subm_2015_ozone_memo_08_31_18.pdf.

The EPA further notes that both New York's petition and the commenters conflate the EPA's use of an air quality threshold at step 2 with the full analysis used under the four-step interstate transport framework as a whole for apportioning responsibility for emissions reductions among upwind states and sources. New York's CAA section 126(b) petition uses a 1 percent threshold to identify states that are linked to the downwind air quality problems and asserts that all the emissions from the named sources that collectively exceed 1 percent are deemed significant. However, this

misunderstands the EPA's use of the air quality threshold in the context of the four-step interstate transport framework. If an upwind state's air quality impact to an identified downwind air quality problem exceeds the threshold as determined at step 2, the EPA then turns to the evaluation of additional cost and air quality factors at step 3 to determine what amount of emissions, if any, from an upwind state should be considered to
significantly
contribute to the downwind air quality problems. If the collective air quality contribution does not exceed the threshold, then emissions from within the state are considered not to significantly contribute to the downwind air quality problem. Thus, the EPA reasonably uses an air quality threshold at step 2 of the four-step interstate transport framework as one aspect of the resolution of the “thorny causation” problem by identifying which states' collective impact is sufficiently large to merit further review of the emissions reduction potential at sources within the state. As the cumulative nature of the ozone problem remains the same whether evaluated under CAA section 110(a)(2)(D)(i)(I) or section 126(b), the EPA believes that it is reasonable to apply a statewide air quality threshold in this case as in the four-step interstate transport framework that it has historically used to implement the good neighbor provision.

The EPA also disagrees that its use of the four-step interstate transport framework precludes the targeted, source-specific remedy provided for by CAA section 126(c). Although the EPA has used regional trading programs to address good neighbor obligations in past rulemakings under both CAA section 110(a)(2)(D)(i)(I) and CAA section 126(b), the application of the framework does not dictate that the remedy at step 4 necessarily be implemented in a particular manner. Thus, the four-step interstate transport framework can be applied in the context of CAA section 126(b) to determine whether a source is operating in violation of the good neighbor provision with sufficient flexibility to permit the application of an appropriately demonstrated remedy under CAA section 126(c), whether through a regional trading program or source-specific emissions limits.

B. The EPA's Standard of Review for This CAA Section 126(b) Petition Regarding the 2008 and 2015 8-Hour Ozone NAAQS

As discussed in Section II.B of this action, section 126(b) of the CAA provides a mechanism for states and other political subdivisions to seek abatement of pollution in other states that may be affecting their air quality. CAA section 126(b) does not, however, identify a specific methodology or specific criteria for the Administrator to apply when making a CAA section 126(b) finding or denying a petition. Therefore, the EPA has the discretion to identify relevant criteria and develop a reasonable approach for evaluating a CAA section 126(b) petition.
See, e.g., Chevron, U.S.A., Inc.
v.
NRDC,
467 U.S. 837, 842-43 (1984);
Smiley
v.
Citibank,
517 U.S. 735, 744-45 (1996).

With respect to the statutory requirements of section 126 and section 110(a)(2)(D)(i) of the CAA, the EPA has consistently acknowledged that Congress created these provisions as two independent statutory tools to address the problem of interstate pollution transport.
See, e.g.,
76 FR 69052, 69054 (November 7, 2011).
30

The fact that Congress did not indicate any preference for one over the other suggests that either tool could serve as a legitimate means to produce the desired result, which is to mitigate significant contribution to nonattainment and interference with maintenance of the NAAQS in downwind states. While the provisions in CAA section 110(a)(2)(D)(i) and section 126 are independent, they are also closely linked. A violation of the prohibition in CAA section 110(a)(2)(D)(i) is a condition precedent for action under CAA section 126(b) and, accordingly, both provisions are reasonably interpreted to construe significant contribution to nonattainment and interference with maintenance identically, since the identical terms are naturally interpreted as meaning the same thing in the two linked provisions.
See Appalachian Power,
249 F. 3d at 1049-50.

30
Courts have also upheld the EPA's position that CAA sections 110(a)(2)(D)(i) and section 126 are two independent statutory tools to address the same problem of interstate transport.
See GenOn REMA, LLC
v.
EPA,
722 F.3d 513, 520-23 (3d Cir. 2013);
Appalachian Power,
249 F.3d at 1047.

Thus, in addressing a CAA section 126(b) petition for ozone transport, the EPA believes it is appropriate to interpret the ambiguous terms incorporated by the cross-reference to CAA section 110(a)(2)(D)(i) (
i.e.,
“contribute significantly to nonattainment” and “interfere with maintenance”)
31

consistent with the EPA's past approach to evaluating interstate ozone pollution transport under the good neighbor provision, and its interpretation and application of that related provision of the statute. As previously discussed, ozone is a regional air pollutant and the EPA's previous analyses and regulatory actions have evaluated the regional interstate ozone transport problem using the four-step interstate transport framework. The EPA most recently applied this four-step interstate transport framework in promulgating the CSAPR Update and the Determination Rule to address interstate transport with respect to the 2008 ozone NAAQS under CAA section 110(a)(2)(D)(i)(I). This approach is particularly applicable with respect to New York's claims regarding the 2008 ozone NAAQS because both rulemakings address projected air quality problems in New York and the impacts of upwind states, including those named in the petition, on such areas.
32

Given the specific cross-reference in CAA section 126(b) to the substantive prohibition in CAA section 110(a)(2)(D)(i), the EPA believes any prior findings made under the good neighbor provision are informative—if not determinative—for a CAA section 126(b) action. Therefore, in this instance, the EPA's decision whether to grant or deny the CAA section 126(b) petition regarding the 2008 8-hour ozone NAAQS depends on application of the four-step interstate transport framework.

31
The Supreme Court confirmed that these terms are ambiguous in
EME Homer City
and that the EPA is therefore delegated the authority to reasonably interpret the provisions. 572 U.S. at 514-15 n.18.

32
The EPA similarly evaluated the impact of Kentucky on New York's air quality after implementation of the CSAPR Update in approving the former state's SIP submission and concluded Kentucky's good neighbor obligations for the 2008 ozone NAAQS were fully addressed by the CSAPR Update. 83 FR 33730 (July 17, 2018). No legal challenges to the EPA's determinations in that SIP action were filed within the period for judicial review.

While the EPA previously applied the four-step interstate transport framework and interpreted significant contribution and interference with maintenance under CAA section 110(a)(2)(D)(i) for the 2008 ozone NAAQS via the CSAPR Update and the Determination Rule, the EPA has not engaged in a regional rulemaking action to apply the good neighbor provision for the 2015 ozone NAAQS. However, the EPA has released technical information intended to inform states' development of SIPs to address the 2015 ozone standard.
33

This information included the results of air quality modeling to identify potential downwind air quality problems in 2023, which we discuss in more detail in

Section III.C.1 of this document. As part of the memorandum releasing the technical information, the EPA acknowledged that states have the flexibility to pursue approaches that may differ from the EPA's historical approach to evaluating interstate transport in developing their good neighbor SIPs.
34

Nonetheless, the EPA's technical analysis and the potential flexibilities identified in the memorandum generally followed the basic elements of the EPA's historical four-step interstate transport framework. As described previously, CAA section 126(b) does not identify a specific methodology or specific criteria for the Administrator to apply when making a CAA section 126(b) finding or denying a petition. Thus, given the EPA's discretion to identify relevant criteria and develop a reasonable approach to inform a CAA section 126(b) finding, the EPA believes that it continues to be appropriate for the Agency to evaluate the claims regarding the 2015 ozone NAAQS in New York's CAA section 126(b) petition consistent with the EPA's four-step interstate transport framework used to evaluate other ozone NAAQS.

33

See
Information on the Interstate Transport State Implementation Plan Submissions for the 2015 Ozone National Ambient Air Quality Standards under Clean Air Act Section 110(a)(2)(D)(i)(I) (March 27, 2018).

34
The EPA has also released two additional memoranda providing guidance to states developing good neighbor SIPs for the 2015 ozone NAAQS.
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); 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). All three memoranda are available in the docket for this final action and at
https://www.epa.gov/airmarkets/memo-and-supplemental-information-regarding-interstate-transport-sips-2015-ozone-naaqs.

Accordingly, because the EPA interprets “contribute significantly to nonattainment” and “interfere with maintenance” to mean the same thing under both CAA sections 110(a)(2)(D)(i)(I) and 126(b), the EPA's decision whether to grant or deny a CAA section 126(b) petition regarding both the 2008 and 2015 ozone NAAQS depends on application of the analysis used to address CAA section 110(a)(2)(D)(i)(I). That is, the EPA assesses whether there is a downwind air quality problem in the petitioning state (
i.e.,
step 1 of the four-step interstate transport framework); whether the upwind state where the source subject to the petition is located is linked to the downwind air quality problem (
i.e.,
step 2); and, if such a linkage exists, whether (balancing various cost and air quality factors) there are cost-effective emissions reductions available from sources in the upwind state to support a conclusion that the sources in the state significantly contribute to nonattainment or interfere with maintenance of the NAAQS (
i.e.,
step 3). If the EPA makes a CAA section 126(b) finding based on its determination that a source or sources will significantly contribute to nonattainment or interfere with maintenance, then the EPA will implement a remedy under CAA section 126(c) to ensure that the violation of the good neighbor provision is addressed through permanent and enforceable measures (
i.e.,
step 4).

In interpreting the phrase “emits or would emit in violation of the prohibition of section [110(a)(2)(D)(i)],” if the EPA or a state has already adopted provisions that eliminate the significant contribution to nonattainment or interference with maintenance of the NAAQS in downwind states, then there simply is no violation of the CAA section 110(a)(2)(D)(i)(I) prohibition. Stated another way, requiring additional reductions from upwind sources would result in eliminating emissions that do not contribute significantly to nonattainment or interfere with maintenance of the NAAQS. Such an action is beyond the scope of the prohibition in CAA section 110(a)(2)(D)(i)(I) and, therefore, beyond the scope of the EPA's authority to make the requested finding under CAA section 126(b).
See EME Homer City,
572 U.S. at 515 n.18, 521-22 (holding the EPA may not require sources in upwind states to reduce emissions by more than necessary to eliminate significant contribution to nonattainment or interference with maintenance of the NAAQS in downwind states under the good neighbor provision).

Thus, it follows that if the EPA approved a state's SIP as adequately meeting the requirements of CAA section 110(a)(2)(D)(i)(I) for a specific NAAQS, the EPA would not find that a source in that state was emitting in violation of the prohibition of CAA section 110(a)(2)(D)(i)(I) absent new information demonstrating that the SIP is now insufficient to address the prohibition for that NAAQS. Similarly, if the EPA has promulgated a FIP that fully eliminates emissions that significantly contribute to nonattainment or interfere with maintenance in a downwind state for a specific NAAQS, the EPA has no basis to find that sources in the upwind state are emitting or would emit in violation of the CAA section 110(a)(2)(D)(i)(I) prohibition, absent new information to the contrary for that NAAQS.

The EPA notes that the approval of a SIP or promulgation of a FIP implementing CAA section 110(a)(2)(D)(i)(I) constitutes a determination that a state's emissions are adequately controlled considering the specific facts that the EPA analyzed while approving the SIP or promulgating the FIP. If a petitioner produces new data or information showing a different level of contribution or other facts the EPA did not consider when approving the SIP or promulgating the FIP, compliance with a SIP or FIP may not be determinative regarding whether the upwind sources emit or would emit in violation of the prohibition of CAA section 110(a)(2)(D)(i)(I).
See
64 FR 28250, 28274 n.15 (May 25, 1999); 71 FR 25328, 25336 n.6 (April 28, 2006);
Appalachian Power,
249 F.3d at 1067 (later developments can be the basis for another CAA section 126 petition). Thus, in circumstances where a state is implementing a SIP or the EPA is implementing a FIP addressing CAA section 110(a)(2)(D)(i)(I) for a particular NAAQS, the EPA will evaluate the CAA section 126(b) petition to determine if the submitted petition raises new information that merits further consideration.

Turning to the comments on the EPA's proposed standard of review, several commenters took issue with the EPA's application of the four-step interstate transport framework under CAA section 126, arguing that in doing so the EPA is “unlawfully eliminating [CAA] section 126 as an independent statutory tool for downwind states.” Commenters disagreed with the EPA's interpretation of the relationship between the good neighbor provision under CAA sections 110(a)(2)(D)(i)(I) and 126(b), contending that Congress intended CAA section 126(b) petitions to be a legal tool to address interstate problems separate and distinct from SIP and FIP actions under CAA section 110. Commenters cite to legislative history and the Third Circuit's opinion in
GenOn,
722 F.3d at 520-23, in support of their assertions that CAA section 126 is intended to remedy interstate transport problems notwithstanding the existence of CAA section 110. Commenters accordingly assert the EPA is incorrect in determining that its four-step interstate transport approach under CAA section 110(a)(2)(D)(i)(I) is appropriate for evaluating under CAA section 126(b) whether an upwind source or group of sources will significantly contribute to nonattainment or interfere with

maintenance of the 2008 and the 2015 ozone NAAQS in a petitioning downwind state.

The EPA has consistently acknowledged in prior actions under CAA section 126(b) that Congress created the good neighbor provision and CAA section 126 as two independent statutory processes to address one problem: Interstate pollution transport.
See, e.g.,
83 FR 26666, 26675 (June 8, 2018) (proposal for this final action); 76 FR 69052, 69054 (November 7, 2011) (proposed action for the EPA's final action on New Jersey's CAA section 126(b) petition regarding SO
2
emissions from Portland Generating Station). As the commenters point out, the Third Circuit has upheld the EPA's position that CAA sections 110(a)(2)(D)(i) and 126 are two independent statutory processes to address the same problem of interstate transport.
See GenOn,
722 F.3d at 520-23. However, the commenters misread the court's holding regarding the EPA's interpretation of the interplay between the two provisions. The Third Circuit spoke to the question of the
timing and sequence
of these processes—specifically, whether the EPA could act on a CAA section 126(b) petition in instances where the Agency had not yet acted on a CAA section 110 SIP addressing interstate transport for the same NAAQS. The Third Circuit also cited to a similar holding by the D.C. Circuit in
Appalachian Power. Appalachian Power,
249 F.3d at 1047. Both courts upheld the EPA's position that it need not wait for the CAA section 110 process to conclude before acting on a CAA section 126(b) petition, thus affirming that both statutory provisions are independent from one another from a timing perspective. But neither court held that the EPA was precluded from applying the same analytical framework to resolving CAA section 126(b) petitions as it applies to analyze states' good neighbor obligations. Here, the Agency has not deferred action on New York's petition regarding the 2015 ozone NAAQS, for which good neighbor SIPs were due on October 1, 2018, until its action on the good neighbor SIPs (for the named upwind states) has concluded. Therefore, by acting on New York's CAA section 126(b) petition regarding the 2015 ozone NAAQS before concluding action on CAA section 110 SIPs, the EPA believes it has given CAA section 126(b) independent meaning as intended by Congress and the courts.

Moreover, the D.C. Circuit's opinion in
Appalachian Power
further supports the EPA's interpretation taken in this action: That while the Agency need not wait for the CAA section 110 process to conclude before acting on a CAA section 126(b) petition, the EPA reasonably imported the four-step interstate transport framework under CAA section 110 to CAA section 126 by interpreting the substantive requirements of the two provisions to be closely linked. The court in
Appalachian Power
specifically considered whether it was appropriate for the EPA to rely on findings made under the good neighbor provision in the NO
X
SIP Call rulemaking in granting several CAA section 126(b) petitions raising similar interstate transport concerns with regards to the same NAAQS. Petitioners in that case argued that the EPA should instead make a finding that “the specified stationary sources within a given state
independently
met [the statute's] threshold test for effect on downwind nonattainment.” 249 F.3d at 1049. The court found that by referring to stationary sources that emit pollutants “in violation of the prohibition of [CAA section 110(a)(2)(D)(i)],” Congress “clearly hinged the meaning of [CAA] section 126 on that of section 110(a)(2)(D)(i).”
Id.
at 1050. The court, therefore, concluded that given CAA section 126's silence on what it means for a stationary source to violate CAA section 110(a)(2)(D)(i), the EPA's approach of relying on findings under CAA section 110(a)(2)(D)(i) was reasonable and, therefore, entitled to deference under
Chevron,
467 U.S. at 843.
See Appalachian Power,
249 F.3d at 1050. The EPA's approach to addressing New York's CAA section 126(b) petition through the application of the four-step interstate transport framework and consideration of findings made in the CSAPR Update and the Determination Rule is therefore reasonable and consistent with prior case law.

Several commenters assert that the EPA cannot rely on recent regional transport rulemakings because they did not fully address good neighbor obligations. Commenters assert that the existence of the CSAPR Update does not foreclose a state from seeking—or the EPA from providing—redress under CAA section 126(b) when the state finds itself struggling to meet NAAQS due to significant upwind contributions or interference. When the EPA promulgated the CSAPR Update it explicitly noted that it only served as a “partial remedy” as to the 2008 ozone NAAQS. Commenters argue that the fact that New York is continuing to experience challenges attaining the 2008 ozone NAAQS demonstrates that significant interstate pollution and associated attainment difficulties remain after the implementation of the CSAPR Update. Commenters therefore assert that the EPA's reliance on the Determination Rule as a complete remedy with respect to the 2008 ozone NAAQS is arbitrary and capricious because the rule fails to eliminate current and ongoing significant contributions by upwind states and sources.

The EPA agrees that the existence of the CSAPR Update does not foreclose redress under CAA section 126(b), but the commenters misstate the EPA's basis for evaluating the petition in light of the CSAPR Update. Although the EPA explained in the proposal that the Determination Rule concluded that the emissions reductions required by the CSAPR Update would fully address covered states' good neighbor obligations for the 2008 ozone NAAQS, the EPA did not rely on these rules (
i.e.,
the CSAPR Update and the Determination Rule) alone to propose denial of the petition.
35

Rather, as described in more detail in Section III.C below, the EPA has reviewed the petition consistent with its interpretation of CAA section 126(b) and the good neighbor provision to see if additional information that was not previously considered by the EPA in either the CSAPR Update or the Determination Rule would justify imposing the additional control requirements that New York requested. As described in Section III.C, the EPA specifically considered the relevance of current air quality in New York. However, based on its evaluation of the information provided in the petition, the EPA has found that the petitioner has not satisfied its burden to demonstrate that the sources named in the petition emit or would emit in violation of the good neighbor provision with respect to either the 2008 or 2015 ozone NAAQS.

35
Similar to Kentucky, the EPA did not rely on its approval of the State's SIP alone to propose denial as to the sources named in that state but considered whether the petition raised new information not previously considered in that action.

C. The EPA's Evaluation of Whether the Petition Is Sufficient To Support a CAA Section 126(b) Finding

This section discusses the approach that the EPA used to review the sufficiency of New York's CAA section 126(b) petition and the EPA's resulting determination that New York has not provided an adequate technical and analytic basis for the EPA to make a finding nor does the EPA have available information to support such a finding.

Consistent with the EPA's approach to evaluating several prior CAA section

126(b) petitions, the EPA interprets CAA section 126(b) as placing an burden on the petitioner to establish a technical and analytic basis for the specific finding requested. Thus, the EPA first looks to see if the petition identifies or contains a sufficient basis to make the requested finding.
See, e.g.,
76 FR 19662, 19666 (April 7, 2011) (proposed response to petition from New Jersey regarding SO
2
emissions from the Portland Generating Station); 83 FR 16064, 16070 (April 13, 2018) (final response to petition from Connecticut regarding ozone emissions from the Brunner Island Steam Electric Station); 83 FR 50444, 50452 (October 5, 2018) (final response to petitions from Delaware and Maryland regarding ozone emissions from four EGU facilities and 36 individual EGUs, respectively).
36

36
The EPA's response to the Maryland and Delaware petition is currently subject to judicial review in the D.C. Circuit.
Maryland
v.
EPA,
No. 18-1285 (D.C. Cir. filed October 15, 2018).

While the EPA interprets CAA section 126(b) as putting the burden on the petitioner, rather than the EPA, to provide a basis or justification for making the requested finding, nothing precludes the EPA from choosing to conduct an independent analysis on a discretionary basis when the Agency determines it would be helpful in evaluating a petition. The EPA has chosen to invoke its discretion in prior actions on CAA section 126(b) petitions concerning ozone, primarily where the Agency already had technical data or findings it could rely on as part of its independent analysis. Notably, because the supplemental information already existed at the time the EPA acted on those petitions, the EPA could leverage such information in its action without undertaking new analyses that would naturally take significantly more time and resources to develop.
37

Consistent with this position and as described further in this section of the notification, the EPA is using supplemental information, when currently available, as part of its discretionary independent analysis of New York's CAA section 126(b) petition. The results of the following analysis support the EPA's determination that New York has not provided an adequate technical and analytic basis for the EPA to make a finding, nor does the EPA's analysis of supplemental information available to it outside of the basis that New York has provided support such a finding.

37

See
83 FR 16064 (April 13, 2018); 83 FR 50444 (October 5, 2018).

1. The EPA's Evaluation of New York's Petition Considering Step 1

As discussed in Section IV.B.1 of the proposal, with respect to step 1 of the four-step interstate transport framework, the EPA began by evaluating New York's petition to determine whether the State identified a downwind air quality problem (nonattainment or maintenance) that may be impacted by ozone transport from other states. The EPA conducted this evaluation for Chautauqua County and the NYMA regarding both the 2008 and 2015 ozone NAAQS.

As discussed in Section II.C of this notification, the EPA typically focuses its analysis regarding potential downwind air quality problems on a future analytic year given the forward-looking nature of the good neighbor obligation in CAA section 110(a)(2)(D)(i)(I). The good neighbor provision requires that states prohibit emissions that “will” significantly contribute to nonattainment or interfere with maintenance of the NAAQS in any other state. The EPA reasonably interprets this language as permitting states and the EPA in implementing the good neighbor provision to prospectively evaluate downwind air quality problems and the need for further upwind emissions reductions.

Particularly relevant to this action, the EPA also applied this interpretation of “will” in the Determination Rule to evaluate remaining good neighbor obligations with respect to the 2008 ozone NAAQS for the CSAPR Update states, including the nine upwind states cited in New York's petition. 83 FR 65889-90. As explained in that action, a key decision informing the application of the interstate transport framework is the selection of a future analytic year. Several court decisions have guided the factors that the EPA considers in selecting an appropriate future analytic year for such an analysis. First, in
North Carolina,
the D.C. Circuit held that the timeframe for implementation of emissions reductions required by the good neighbor provision should be selected by considering the relevant attainment dates of downwind nonattainment areas affected by interstate transport of air pollution. 531 F.3d at 911-12. Moreover, the Supreme Court and the D.C. Circuit have both held that the EPA may not over-control upwind state emissions relative to the downwind air quality problems. Specifically, the courts found that the Agency may not require emissions reductions (at steps 3 and 4 of the interstate transport framework) from a state that are greater than necessary to achieve attainment and maintenance of the NAAQS in all the downwind areas to which that state is linked.
See EME Homer City,
572 U.S. at 521-22;
EME Homer City II,
795 F.3d at 127, 129-30 (on remand from the Supreme Court, finding ozone-season NO
X
budgets for ten states invalid because the EPA's modeling showed that the downwind air quality problems to which these states were linked would be resolved by the time the budgets would be implemented). These court decisions support the Agency's choice to use a future analytic year to help ensure that any emissions reductions that the EPA may require of sources in upwind states neither over- or under-control emissions with respect to the EPA's projections as to downwind air quality at the time by which that those controls could feasibly be implemented.

In the Determination Rule, the EPA established the appropriate future analytic year for purposes of assessing remaining interstate transport obligations for the 2008 ozone NAAQS. 83 FR 65889-890. The EPA's analysis considered two primary factors: (1) The applicable attainment dates for the 2008 ozone NAAQS; and (2) the timing to feasibly implement new NO
X
control strategies not previously addressed in the CSAPR Update. As the applicable attainment dates, the EPA explained that the next attainment dates for the 2008 ozone NAAQS would be July 20, 2021, for nonattainment areas classified as Serious, and July 20, 2027, for nonattainment areas classified as Severe.

In the Determination Rule, the EPA then evaluated the timeframe necessary to implement additional NO
X
control strategies at various sources across the region. 83 FR 65893-901. For EGUs, the EPA explained that it was appropriate to consider the timeframe required for implementation of selective catalytic reduction (SCR) across the region because of the potential for larger emissions reductions as compared to selective non-catalytic reduction (SNCR). The EPA determined that SCR project development and installation can require up to 39 months for an individual power plant installing controls on more than one boiler,
38

and that a minimum of 48 months (4 years) is a reasonable time-period needed to complete all necessary steps of SCR projects at EGUs on a regional scale, considering the necessary stages of post-

combustion control project planning, shepherding of labor and material supply, installation, coordination of outages, testing, and operation. The EPA further concluded that SNCR installations, while generally having shorter project timeframes (
i.e.,
up to 16 months for an individual power plant installing controls on more than one boiler), share similar implementation steps with and need to account for the same regional factors as SCR installations.
39

The EPA, therefore, concluded that it may reasonably take up to 4 years to install the new emissions controls regionwide for EGUs.

38

See
Table 3-1 in Engineering and Economic Factors Affecting the Installation of Control Technologies for Multipollutant Strategies. EPA Final Report. EPA-600/R-02/073. October 2002. Available at
https://cfpub.epa.gov/si/si_public_record_report.cfm?Lab=NRMRL&dirEntryId=63473.

39

See
the month-by-month evaluation of SNCR installation presented in Exhibit A-6 in Engineering and Economic Factors Affecting the Installation of Control Technologies for Multipollutant Strategies. EPA Final Report. EPA-600/R-02/073. October 2002. Available at
https://cfpub.epa.gov/si/si_public_record_report.cfm?Lab=NRMRL&dirEntryId=63473.
Evaluation of implementation timeframes for various control strategies is also found in the EPA's CSAPR Update EGU NO
X
Mitigation Strategies Final Rule TSD.
See
Docket ID No. EPA-HQ-OAR-2015-0500 (available at
http://www.regulations.gov
).

The EPA further explained that many of the same considerations affecting the EPA's analysis of regionwide implementation of controls at EGUs would also affect the regionwide implementation of controls at non-EGUs, which may be more complex considering the diversity of non-EGU sources as well as the greater number and smaller size of the individual sources. 83 FR 65901-04. The EPA noted that preliminary estimates for the implementation of some potential control technologies on non-EGUs only account for the time between bid evaluation and startup but do not account for additional considerations such as pre-bid evaluation studies, permitting, and installation of monitoring equipment. In addition, these preliminary estimates for implementing control technologies do not include the time and resources needed to install such technologies on a sector- or region-wide basis. Accordingly, the EPA concluded that it was reasonable to assume for purposes of the Determination Rule that an expeditious timeframe for installing sector- or region-wide controls on non-EGU sources could also be 4 years or more.

Considering the timeframes for regionwide implementation of control strategies and the timeframe in which a rulemaking requiring such controls would be finalized, the EPA concluded that reductions from such control strategies were unlikely to be implemented for a full ozone season until 2023. The EPA acknowledged that 2023 is later than the attainment date for nonattainment areas classified as Serious (July 20, 2021), but concluded that it was unlikely emissions control requirements could be feasibly promulgated and implemented by that earlier date. Moreover, the EPA noted that 2023 was well in advance of the subsequent attainment date for areas classified as Severe. Accordingly, the EPA determined that 2023 was a reasonable year to assess downwind air quality to evaluate any remaining requirements under the good neighbor provision for the 2008 ozone NAAQS. 83 FR 65901-05.

After selecting the analytic year, the EPA then used the Comprehensive Air Quality Model with Extensions (CAMx v6.40) to model emissions in 2011 and 2023, based on updates provided to the EPA from states and other stakeholders on a January 6, 2017, Notice of Data Availability (NODA).
40 41

This updated modeling was used in the Determination Rule to estimate ozone design values in 2023, as described in the Determination Rule Air Quality Modeling Technical Support Document (TSD).
42

The EPA used outputs from the 2011 and 2023 model simulations to project base period 2009-2013 average and maximum ozone design values to 2023 at monitoring sites nationwide. In projecting future year design values, the EPA applied its own modeling guidance,
43

which recommends using model predictions from the “3 x 3” array of grid cells surrounding the location of the monitoring site.
44

Considering the comments on the January 2017 NODA and other analyses, the EPA also projected 2023 design values based on a modified version of the “3 x 3” approach for those monitoring sites located in coastal areas. Briefly, in this alternative approach, the EPA eliminated from the design value calculations those modeling data in grid cells that are dominated by water (
i.e.,
more than 50 percent of the area in the grid cell is water) and that do not contain a monitoring site (
i.e.,
if a grid cell is more than 50 percent water but contains an air quality monitor, that cell would remain in the calculation).
45

For each individual monitoring site, the base period 2009-2013 average and maximum design values, and the 2023 projected average and maximum design values (based on both the “3 x 3” approach and the alternative approach) affecting coastal sites are available in Excel format in the docket for this action and in PDF format at
https://www.epa.gov/airmarkets/memo-supplemental-information-interstate-transport-sips-2008-ozone-naaqs.

40
Using the 2023 analytic year also allowed the EPA to begin the updated analysis using the data sets originally developed for a January 2017 Notice of Data Availability (NODA) (82 FR 1733, January 6, 2017), which the EPA revised in response to stakeholder feedback. Accordingly, the EPA initiated its analysis more quickly than if a different year had been chosen, which might have delayed subsequent rulemaking actions and therefore emissions reductions.

41

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). This memorandum also supplements the information provided in, “Supplemental 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).” Memorandum from Stephen D. Page, Director, U.S. EPA Office of Air Quality Planning and Standards, to Regional Air Division Directors, Regions 1-10. October 27, 2017. Available at
https://www.epa.gov/sites/production/files/2017-10/documents/final_2008_o3_naaqs_transport_memo_10-27-17b.pdf.

42
Air Quality Modeling Technical Support Document for the Updated 2023 Projected Ozone Design Values. U.S. EPA Office of Air Quality Planning and Standards. June 2018. Document developed to support the Determination Rule, 83 FR 65878 (December 21, 2018). Available at
https://www.epa.gov/airmarkets/air-quality-modeling-technical-support-document-updated-2023-projected-ozone-design.

43
“Draft Modeling Guidance for Demonstrating Attainment of Air Quality Goals for Ozone, PM
2.5
, and Regional Haze.” Memorandum from Richard Wayland, Division Director, Air Quality Assessment Division, U.S. EPA Office of Air Quality Planning and Standards, to Regional Air Division Directors, Regions 1-10. December 3, 2014. Available at
https://www3.epa.gov/scram001/guidance/guide/Draft-O3-PM-RH-Modeling_Guidance-2014.pdf.

44
The EPA's modeling uses 12km
2
grid cells.

45
A model grid cell is identified as a “water” cell if more than 50 percent of the grid cell is water based on the 2006 National Land Cover Database. Grid cells that meet this criterion are treated as entirely over water in the WRF modeling used to develop the 2011 meteorology for the EPA's air quality modeling. (
See
Air Quality Modeling Technical Support Document for the Updated 2023 Projected Ozone Design Values. U.S. EPA Office of Air Quality Planning and Standards. June 2018. Document developed to support the Determination Rule, 83 FR 65878 (December 21, 2018). Available at
https://www.epa.gov/airmarkets/air-quality-modeling-technical-support-document-updated-2023-projected-ozone-design.
)

In the Determination Rule, the EPA followed the same approach for identifying receptors based on this modeling as in the CSAPR Update rulemaking process. That is, the EPA considered a combination of modeling projections and monitoring data to identify receptor sites that are projected to have problems attaining or maintaining the NAAQS.
46

Specifically, the EPA identified nonattainment receptors as those monitoring sites with current measured values exceeding the NAAQS that also have projected (
i.e.,
in 2023) average design values exceeding the NAAQS. The EPA also identified maintenance receptors as those

monitoring sites with projected maximum design values exceeding the NAAQS. Specifically, maintenance receptors included sites with current measured values below the NAAQS with projected average and maximum design values exceeding the NAAQS and monitoring sites with projected average design values below the NAAQS but with projected maximum design values exceeding the NAAQS.

46

See
81 FR 74530-74532 (October 26, 2016).

Pertinent to this action, the EPA's examination in the Determination Rule of the 2023 projected design values for Chautauqua County indicates that this area is not projected to be in nonattainment or have a maintenance problem in 2023 for either the 2008 or the 2015 ozone NAAQS. The EPA's examination of the 2023 projected design values for the NYMA indicates that this area is not projected to be in nonattainment or have a maintenance problem in 2023 for the 2008 ozone NAAQS. However, the EPA's modeling indicates that the NYMA is projected to be in nonattainment in 2023 with respect to the 2015 ozone NAAQS.

Because the EPA has already conducted a rulemaking evaluating good neighbor obligations for the 2008 ozone NAAQS under CAA section 110(a)(2)(D)(i)(I) in which the Agency used 2023 as the future analytic year and because, as discussed previously, CAA section 126(b) directly incorporates the CAA section 110(a)(2)(D)(i) standard, the EPA believes it is also appropriate to consider the 2023 modeling conducted for the Determination Rule in evaluating whether New York's petition has adequately demonstrated that there will be a downwind air quality problem with respect to the 2008 ozone NAAQS in Chautauqua County and the NYMA.
47

Moreover, the EPA believes it is appropriate to consider the 2023 modeling when evaluating the petition's claims with respect to the 2015 ozone NAAQS because the 2023 ozone season aligns with the attainment year for the 2015 NAAQS in Moderate ozone nonattainment areas, consistent with the D.C. Circuit's instruction in
North Carolina.
48

As explained at proposal, while the EPA is not in this action reopening the analysis and findings made in the Determination Rule with respect to the 2008 ozone NAAQS, the EPA evaluated the petition, consistent with the standard of review described in Section III.B, to determine whether additional information not considered in the Determination Rule should influence the EPA's finding as to whether the sources named in New York's petition emit or would emit in violation of the prohibition of CAA section 110(a)(2)(D)(i)(I).

47

See
n.1,
supra,
regarding the potential impact on this final action of the September 13, 2019, decision of the D.C. Circuit in
Wisconsin
v.
EPA,
No. 16-1406.

48
The 2023 ozone season represents the last full season from which data can be used to determine attainment with the 2015 ozone NAAQS by the August 3, 2024, attainment date for nonattainment areas classified as Moderate.

The New York petition raises concerns about the assumptions and results of the EPA's modeling. Specifically, the petition indicates significant concerns with the EPA's expectation that uncontrolled EGUs will reduce their emissions rates in the absence of unit-level enforceable limits and with the EPA's treatment of model cells containing a land/water interface. The petition does not further elaborate on the basis for these concerns, and the EPA, therefore, has no reason to believe that its 2023 modeling is unreliable. Moreover, the EPA already addressed concerns regarding the EGU assumptions in the 2023 modeling in response to comments raised in the Determination Rule.
See
83 FR 65886-89 (explaining statutory rationale regarding when enforceable emissions limitations are required and responding to comments); 83 FR 65913-15 (responding to comments concerning projections of EGU emissions in 2023).
49

49
The EPA's conclusions regarding the EGU assumptions in the 2023 modeling are also the subject of judicial review in the D.C. Circuit.
New York
v.
EPA,
No. 19-1019 (D.C. Cir.).

As described earlier in this section, the EPA also addressed concerns regarding the treatment of model cells containing land/water interface in the Determination Rule by calculating design values using two different methodologies. 83 FR 65917. The petition does not provide any new information not already considered by the EPA in the Determination Rule as to these issues and therefore, the EPA has no basis to reconsider its conclusions finalized in that action.

The EPA received several comments challenging the conclusion that it is appropriate to evaluate air quality in a future year to determine whether there is a violation of the good neighbor provision in evaluating New York's CAA section 126(b) petition. First, the EPA received comments asserting that the EPA's reliance on the term “will” as it appears in the good neighbor provision to justify consideration of air quality in a future year is inconsistent with the plain language of the CAA. Commenters contend that Congress specified that implementation plans under CAA section 110(a)(2)(D)(i) must prohibit “any” pollution from “any” source that will contribute significantly to nonattainment and interfere with maintenance, and that this includes pollution that will do so between now and 2023.

The EPA does not agree that analysis of air quality in a future year is inconsistent with the statute. The EPA reasonably interprets the word “will” in the good neighbor provision as permitting states and the EPA in implementing the good neighbor provision to prospectively evaluate downwind air quality problems and the need for further upwind emissions reductions. In the EPA's prior regional transport rulemakings, the Agency has routinely evaluated whether upwind states “will” significantly contribute to nonattainment or interfere with maintenance based on projections of air quality in the future year in which any emissions reductions would be expected to go into effect. For the 1998 NO
X
SIP Call, the EPA used an analytic year of 2007. For the 2005 CAIR, the Agency used analytic years of 2009 and 2010 for ozone and PM
2.5
, respectively. 63 FR 57450; 70 FR 25241. The EPA applied the same approach in finalizing CSAPR in 2011, the CSAPR Update in 2016, and the Determination Rule in 2018 by evaluating air quality in 2012, 2017 and 2023, respectively. 76 FR 48211; 81 FR 74537.

The D.C. Circuit affirmed the EPA's interpretation of “will” in CAIR, finding the EPA's consideration of future projected air quality (in addition to current measured data) to be a reasonable interpretation of an ambiguous term.
North Carolina,
531 F.3d at 913-14. The
North Carolina
court affirmed the EPA's interpretation, explaining that “will” “can mean either certainty or indicate the future tense” and held that it is reasonable for the EPA to give effect to both potential meanings of the word.
Id.
Thus, although the court acknowledged that the term “will” could refer to the certainty of an upwind state's impact on a downwind state (
i.e.,
based on current measured nonattainment), the court also clearly acknowledged the ambiguity of this term and indicated this was not the only reasonable interpretation. Given this ambiguity, the D.C. Circuit affirmed that the EPA's approach is permissible under the Act.

While the EPA agrees that the references to “any” in CAA section 110(a)(2)(D)(i) mean that any source of emissions of any air pollutant having the requisite impact may be subject to control under that provision, the commenter does not explain how this term limits the EPA's discretion to

evaluate of future air quality when evaluating whether such emissions have the requisite impact on downwind areas and therefore whether such control is necessary or authorized. Rather, as the commenter fails to acknowledge, the EPA is only authorized under the good neighbor provision to require the prohibition of such emissions in “amounts which will” improperly impact another state with respect to the NAAQS. The Supreme Court has held that this language means that any emissions reductions imposed under the good neighbor provision be no greater than necessary to address downwind NAAQS,
i.e.,
that the EPA avoid unnecessary over-control of emissions from upwind states.
See EME Homer City,
572 U.S. at 521-22. In interpreting that decision, the D.C. Circuit declared the EPA's emissions reduction requirements for certain states to be invalid under the good neighbor provision where the EPA had information indicating that there will be no downwind air quality problems by the time the emissions reductions would have been implemented.
See EME Homer City II,
795 F.3d at 130. Thus, the EPA does not agree that it is obligated to impose emissions reductions if there will be no downwind air quality issues to address by the time such reductions could be in place.

Several commenters contend that, by evaluating air quality in a future year the EPA fails to give “emits” in the phrase “emits or would emit” under CAA section 126(b) independent meaning, thereby unreasonably ignoring existing air quality issues in evaluating CAA section 126(b) petitions. Commenters contend that the provision is intended to provide relief for both current and future attainment and maintenance problems, with one commenter noting that the “or” conjunction indicates that the criteria for demonstrating a violation could be fulfilled either through current or future conditions. Thus, the commenters conclude that it is inappropriate for the EPA to rely on the word “will” in the good neighbor provision to base its analysis on future air quality without considering current conditions.

One commenter further asserts that the EPA's forward-looking approach to interpreting the requirements of CAA section 126(b) is inconsistent with its prior grant of a CAA section 126(b) petition from New Jersey, which was based on the named source's current and ongoing emissions.
50

The commenter cites the Third Circuit's decision which upheld the EPA's action on the petition in
GenOn,
indicating that the court noted, in construing the timing provisions of CAA section 126 “that a statute ought, upon the whole, to be so construed that, if it can be prevented, no clause, sentence, or word shall be superfluous, void, or insignificant.” 722 F.3d 513, 520-21 (3d Cir. 2013) (quoting
TRW Inc.
v.
Andrews,
122 S. Ct. 441 (2001)).

50
Final Response to Petition from New Jersey Regarding SO
2
Emissions From the Portland Generating Station, 76 FR 69052 (November 7, 2011) (finding facility in violation of the prohibitions of CAA section 110(a)(2)(D)(i)(I) with respect to the 2010 SO
2
NAAQS prior to issuance of designations for that standard).

The EPA agrees it must give meaning to the statutory terms of CAA section 126(b) and has done so here. As an initial matter, certain commenters misconstrue the EPA's forward-looking evaluation of air quality impacts under CAA section 126(b) as stemming from the phrase “would emit” under this provision. As described in this section, the EPA looks to future
air quality
impacts under CAA section 126(b) because of the future-looking reference in the word “will” under the good neighbor provision, a violation of which is the explicit condition precedent for making the requested finding under CAA section 126(b). As explained in the EPA's prior actions under

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Source: Frix Law Library, https://www.frixlaw.com/law-library/documents/fr%3A2019-21207. Public record. Not legal advice.