Final Response to Petition From New Jersey Regarding SO2, 69052-69077 [2011-28816]

Agencies

• ENVIRONMENTAL PROTECTION AGENCY

[Federal Register Volume 76, Number 215 (Monday, November 7, 2011)]
[Rules and Regulations]
[Pages 69052-69077]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2011-28816]



[[Page 69051]]

Vol. 76

Monday,

No. 215

November 7, 2011

Part VII





Environmental Protection Agency





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40 CFR Part 52





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Final Response to Petition From New Jersey Regarding SO2 
Emissions From the Portland Generating Station; Final Rule

Federal Register / Vol. 76, No. 215 / Monday, November 7, 2011 / 
Rules and Regulations

[[Page 69052]]


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ENVIRONMENTAL PROTECTION AGENCY

40 CFR PART 52

[EPA-HQ-OAR-2011-0081; FRL-9487-8]
RIN 2060-AQ69


Final Response to Petition From New Jersey Regarding 
SO2 Emissions From the Portland Generating Station

AGENCY: Environmental Protection Agency (EPA).

ACTION: Final rule.

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SUMMARY: The EPA is making a finding that the coal-fired Portland 
Generating Station (Portland), owned and operated by GenOn REMA LLC 
(GenOn), in Upper Mount Bethel Township, Northampton County, 
Pennsylvania, is emitting air pollutants in violation of the interstate 
transport provisions of the Clean Air Act (CAA or Act). Specifically, 
the EPA finds that emissions of sulfur dioxide (SO2) from 
Portland significantly contribute to nonattainment and interfere with 
maintenance of the 1-hour SO2 national ambient air quality 
standard (NAAQS) in New Jersey. This finding is made in response to a 
petition submitted by the State of New Jersey Department of 
Environmental Protection (NJDEP) on September 17, 2010. In this action, 
the EPA is establishing emission limitations and compliance schedules 
to ensure that Portland will eliminate its significant contribution to 
nonattainment and interference with maintenance of the 1-hour 
SO2 NAAQS in New Jersey. Compliance with these limits will 
permit the continued operation of Portland beyond the 3-month limit 
established by the CAA for sources subject to a contribution finding.

DATES: This final rule is effective on January 6, 2012.

ADDRESSES: The EPA has established a docket for this action under 
Docket ID No. EPA-HQ-OAR-2011-0081. All documents in the docket are 
listed on the https://www.regulations.gov Web site. Although listed in 
the index, some information is not publicly available, e.g., 
confidential business information (CBI) or other information whose 
disclosure is restricted by statute. Certain other material, such as 
copyrighted material, will be publicly available only in hard copy 
form. Publicly available docket materials are available either 
electronically through https://www.regulations.gov or in hard copy at 
the Air and Radiation Docket and Information Center, EPA/DC, EPA West 
Building, Room 3334, 1301 Constitution Ave. 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 
Docket is (202) 566-1742.

FOR FURTHER INFORMATION CONTACT: Mr. Todd Hawes (919) 541-5591, 
hawes.todd@epa.gov, or Ms. Gobeail McKinley (919) 541-5246, 
mckinley.gobeail@epa.gov, Office of Air Quality Planning and Standards, 
Air Quality Policy Division, Mail Code C539-04, Research Triangle Park, 
NC 27711.

SUPPLEMENTARY INFORMATION: 

Table of Contents

I. Executive Summary
II. Summary of Changes From the April 7, 2011 Proposed Rule
III. The Basis for Making the Section 126 Finding for Portland
    A. CAA Section 126(b) and Our Legal Authority
    B. Summary of Comments and Responses Regarding Legal Authority
IV. Summary and Assessment of the Modeling and Other Data Relevant 
to the EPA's Proposed Finding
    A. Summary of the Modeling for the Proposed Rule
    1. Modeling Analysis in NJDEP's Section 126 Petition
    a. Model Selection
    b. Meteorological Data
    2. The EPA's Modeling Analysis To Quantify Significant 
Contribution
    B. Public Comments Related to the Modeling
    1. Model Selection
    2. Meteorological Data
    3. Emissions and Source Characteristics
    4. Identification of Background Concentrations
    5. Columbia Monitor Data and Analyses
    C. Modeling and Other Analyses To Determine Significant 
Contribution for the Final Rule
V. Establishing the Emission Limits Necessary for the Remedy
    A. Quantification of Necessary Emission Reductions
    B. Summary of the EPA's Proposed Remedy Analysis
    C. Summary of Comments and Responses Regarding the Remedy 
Modeling
    D. The Final Remedy Limit
    E. Compliance Schedule for the Final Remedy Limit
    1. Proposed Compliance Schedule
    2. Public Comments and the EPA's Responses
    a. Technical Feasibility
    b. Continued Operation of Facility in the Interim Period
    c. Harmonization With Other Requirements
    3. The Final Rule
    F. Other Considerations for Establishing the Final Remedy
    1. Economic Feasibility
    2. Requirement for Continuous Monitoring
    3. Delegation of Enforcement
VI. Increments of Progress
    A. Interim Emission Limits
    1. What the EPA Proposed
    2. Public Comments and the EPA's Responses
    a. Appropriateness of Including Interim Emissions Limits
    b. Technical Feasibility of Coal Switching
    c. Interim Limits Suggested by the GenOn Test Burn Report
    d. Load Shifting
    e. One-Year Time Period
    f. Effect of Interim Limits on Reliability
    g. Clear Rational for Limits
    h. Combined Emission Limits
    3. Final Rule Interim Emission Limits
    B. Increments of Progress: Reporting Milestones
    1. What the EPA Proposed
    2. Public Comments and the EPA's Responses
    3. Final Rule Reporting Milestones
VII. Alternate Compliance Schedule and Consideration of Petition for 
Rulemaking for Alternative Emission Limits
    A. Alternate Compliance Schedule if the Source Owner Opts To 
Cease Operations
    1. What the EPA Proposed
    2. Public Comments and the EPA's Responses
    3. The Final Rule
    B. Consideration of Petition for Rulemaking for Alternative 
Emission Limits
VIII. Statutory and Executive Order Reviews
    A. Executive Order 12866: Regulatory Planning and Review and 
Executive Order 13563: Improving Regulation and Regulatory Review
    B. Paperwork Reduction Act
    C. Regulatory Flexibility Act
    D. Unfunded Mandates Reform Act of 1995
    E. Executive Order 13132: Federalism
    F. Executive Order 13175: Consultation and Coordination With 
Indian Tribal Governments
    G. Executive Order 13045: Protection of Children From 
Environmental Health and Safety Risks
    H. Executive Order 13211: Actions That Significantly Affect 
Energy Supply, Distribution, or Use
    I. Executive Order 12898: Federal Actions To Address 
Environmental Justice in Minority Populations and Low-Income 
Populations
    J. National Technology Transfer and Advancement Act
    K. Congressional Review Act
    L. Judicial Review

I. Executive Summary

    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 
upwind states emits or would emit any air pollutant in violation of the 
prohibition of section110(a)(2)(D)(i),\1\ 42

[[Page 69053]]

U.S.C. 7426(b). On September 17, 2010, NJDEP filed a section 126 
petition requesting that the EPA find that emissions from Portland, 
located in Upper Mount Bethel Township, Northampton County, 
Pennsylvania, significantly contribute to nonattainment or interfere 
with maintenance of the 1-hour SO2 NAAQS in New Jersey. In 
this action, the EPA is granting that petition, and basing its finding 
on the review of NJDEP's air quality modeling, the EPA's independent 
assessment of the AERMOD \2\ dispersion modeling, and other technical 
analyses. Based on this assessment, the EPA finds that Portland's 
emissions significantly contribute to nonattainment and interfere with 
maintenance of the 1-hour SO2 NAAQS in New Jersey. Pursuant 
to section 126(c), the EPA is also authorizing continued operation of 
the plant consistent with emission limitations and compliance schedules 
(including increments of progress) set forth in this rule to bring the 
plant into compliance as expeditiously as practicable with the CAA 
prohibition on emissions that significantly contribute to nonattainment 
and interfere with maintenance of the 1-hour SO2 NAAQS. 
Specifically, the final rule requires Portland to reduce its 
SO2 emissions to meet the following limits: 1,105 pounds per 
hour (lb/hr) for unit 1; 1,691 lb/hr for unit 2; and 0.67 pounds per 
million metric British units (lb/mmBtu), based on a 30 boiler operating 
day rolling average, for units 1 and 2. Portland must achieve and 
maintain these emission limitations by no later than 3 years after the 
effective date of this rule. The EPA is establishing an interim 
SO2 emission limit requirement to ensure that Portland 
demonstrates appropriate increments of progress toward final 
compliance. Specifically, no later than 1 year after the effective date 
of this rule, total SO2 emissions from units 1 and 2 
combined may not exceed 6,253 lb/hr. The final rule also requires 
Portland to submit to the EPA a dispersion modeling protocol within six 
months of the effective date of the rule, a modeling analysis 
demonstrating the elimination of significant contribution to 
nonattainment and interference with maintenance within 1 year of the 
effective date of the rule, semi-annual interim progress reports, and a 
final progress report to demonstrate compliance with the interim and 
final emission limits. Compliance with the final emission limits 
established in this rule is sufficient to remedy Portland's significant 
contribution to nonattainment and interference with maintenance in the 
impacted areas in New Jersey.
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    \1\ The text of section 126 codified in the United States Code 
cross references section 110(a)(2)(D)(ii) instead of section 
110(a)(2)(D)(i). The courts have confirmed that this is a 
scrivener's error and the correct cross reference is to section 
110(a)(2)(D)(i), See Appalachian Power Co. v. EPA, 249 F.3d 1032, 
1040-44 (DC Cir. 2001).
    \2\ AERMOD stands for the American Meteorological Society/
Environmental Protection Agency Regulatory Model.
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II. Summary of Changes From the April 7, 2011 Proposed Rule

    The following is a summary of the significant changes made since 
proposal. Each of these changes is discussed later in this notice, and, 
where noted, additional information is provided in other supporting 
documentation in the docket for this rulemaking. The first change is 
that the final compliance remedy now includes a heat input-based 
SO2 emission limit of 0.67 lb/mmBtu for units 1 and 2, in 
addition to the proposed SO2 emission rate limits. The heat-
input based SO2 emission limit is based on a 30 boiler 
operating day rolling average. This additional requirement was made to 
address concerns raised by commenters that the proposed compliance 
remedy was not adequate to ensure attainment of the NAAQS in New 
Jersey. This issue is discussed in more detail in section V.
    Second, the interim emission rate limits, proposed as 2,910 lb/hr 
for unit 1 and 4,450 lb/hr for unit 2, and having a compliance date of 
no later than 1 year from the effective date of this rule, are now 
expressed as a single limit for units 1 and 2 combined, and may not 
exceed 6,253 lb/hr. The 1-year compliance timeframe remains unchanged. 
This change to the limit is partly in response to comments (including 
those from GenOn) in support of greater operational flexibility, and 
acknowledges that the interim limit need not be unit specific. It is 
also based on the availability of lower sulfur coal than the coal 
Portland is currently using. Additional details are provided in section 
VI.C.
    Third, in response to comments that the proposed deadlines for 
submitting a modeling protocol and modeling analysis were too short, 
the deadline for submitting the modeling protocol is changed to six 
months after the effective date of this rule, and the requirement to 
submit a modeling analysis is changed to 12 months after the effective 
date of this rule. This will allow Portland more time for planning its 
modeling analysis but does not change the compliance time frames for 
meeting the emission limits.
    Additionally, in response to comments suggesting the plant needed 
more than 90 days to determine a method of compliance, the final rule 
gives Portland 12 months from the effective date to indicate how it 
intends to achieve full compliance. The EPA agrees that the plant may 
need 12 months to identify the specific engineering and technology 
decisions to determine how to reach compliance within 3 years. 
Accordingly, we are eliminating the proposed requirement for Portland 
to notify the EPA, within 90 days from the effective date of this rule, 
whether the plant will continue to operate and comply with the emission 
limits and compliance schedules, or cease operations. The modeling 
protocol and the initial semi-annual progress report, due 6 months 
after the effective date of this rule, will appropriately inform 
Portland's plans for continuing operation. Finally, the EPA is not 
requiring separate compliance schedules and analyses should Portland 
decide to permanently cease operation of unit 1 and unit 2 as a means 
of compliance. The final and interim emission limits and compliance 
schedules are appropriate regardless of how Portland ultimately decides 
to meet them. Thus, we decided it was not necessary, as proposed, to 
include a separate schedule specifically for a compliance approach 
based on shutting down.

III. The EPA's Basis for Making the Section 126 Finding for Portland

A. CAA Section 126(b) and Our Legal Authority

    The statutory authority for this action is provided by the CAA, as 
amended, 42 U.S.C. 7401 et seq. Section 126 of the CAA provides 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 
upwind states emits or would emit any air pollutant in violation of the 
prohibition of section 110(a)(2)(D)(i). 42 U.S.C. 7426(b). If the EPA 
makes such a finding, in order to allow continued operation of the 
source, the EPA may also issue emission limits and compliance schedules 
(including increments of progress) to bring the source into compliance 
as expeditiously as practicable but no later than 3 years from the date 
of the finding. Absent such emission limits and a compliance schedule, 
the source may not continue operations beyond 90 days.
    Section 110(a)(2)(D) of the CAA, often referred to as the ``good 
neighbor'' or ``interstate transport'' provision of the Act, addresses 
interstate transport of air pollution. Under section 110(a)(2)(D)(i), 
emissions in one state that contribute significantly to nonattainment 
in, or interfere with maintenance of a NAAQS

[[Page 69054]]

by, any other state, or interfere with measures required to be included 
in the applicable implementation plan for any other state under part C 
to prevent significant deterioration of air quality or to protect 
visibility, are to be prohibited. 42 U.S.C. 7410(a)(2)(D)(i). Findings 
by the Administrator, made pursuant to section 126, that a source or 
group of sources emits air pollutants in violation of the section 
110(a)(2)(D)(i) prohibition are commonly referred to as section 126 
findings. Similarly, petitions submitted pursuant to this section are 
commonly referred to as section 126 petitions. This action responds to 
a section 126 petition submitted by the NJDEP. In this action, the EPA 
makes a section 126 finding with respect to Portland and establishes 
emission limits and compliance schedules to permit continued operation 
of the plant.
    Several commenters asserted that the EPA cannot, or should not, 
make such a section 126 finding at this time, but can only make such a 
finding after the state has submitted what is usually referred to as 
its ``interstate transport'' or section 110(a)(2)(D) State 
Implementation Plan (SIP). For the recently promulgated 1-hour 
SO2 standard, those SIPs are due on June 3, 2013. We 
disagree with this interpretation of the Act. The plain language of the 
statute confirms that section 126 remedies can, and in some cases must, 
be promulgated prior to the deadline for states to make SIP submissions 
under section 110(a)(2)(D).
    The EPA has consistently interpreted the language in section 126 as 
referring to a functional prohibition on emissions. This interpretation 
is supported by the plain language of the statute, the statutory 
structure, and the legislative history. Further, the EPA notes that the 
statute does not exempt, for any period of time, violations of the 
prohibition from scrutiny under section 126. For these reasons, the EPA 
believes its interpretation is compelled by the statutory language. 
Nonetheless, to the extent that the statutory language is ambiguous, 
the EPA's reasonable interpretation of this language is to be accorded 
deference.
    The EPA interprets the language in section 126 as referring to the 
actual functional prohibition of section 110(a)(2)(D)(i) that bars 
impermissible interstate transport. The EPA does not agree with the 
position taken by some commenters that the language refers only to an 
emissions limitation contained in a state's section 110(a)(2)(D) SIP. 
Further, there is nothing in the statute to support the argument that 
the prohibition on emissions does not arise until after the SIP 
submission deadline, or that a violation of the functional prohibition 
cannot occur before that deadline. Where the EPA finds such a violation 
exists, it must, under section 126, issue emission limits and 
compliance schedules to permit continued operation of the source.
    The EPA's interpretation of section 126 acknowledges that Congress 
created two independent statutory tools--section 110(a)(2)(D)(i) and 
section 126--to address the problem of interstate pollution transport. 
The purpose of each provision is to control upwind emissions that 
contribute significantly to downwind states' nonattainment or 
maintenance problems. The two provisions differ in that one relies on 
state regulation and the other relies on federal regulation. Congress 
provided both provisions without indicating any preference for one over 
the other, suggesting it viewed either approach as a legitimate means 
to produce the desired result. Instead, the statutory language creates 
two independent tools to address the problem. Section 110(a)(2)(D)(i) 
establishes an obligation for all states to address emissions within 
the state significantly contributing to downwind air quality problems 
or interfering with certain regulatory provisions in downwind states. 
Section 126 establishes a procedure for a state, or political 
subdivision, to petition the EPA to take federal action to address 
transported emissions from an identified source or group of sources in 
another state. The two provisions are independent, and nothing in the 
statute suggests that one is intended to limit the other.
    In general, statutes are to be interpreted in a way that gives 
meaning to each section. The EPA's interpretation of section 126 is 
consistent with this general rule in that it gives section 126 a 
purpose independent of the other remedies available under the CAA. In 
contrast, if section 126 were interpreted as referring only to a 
prohibition contained in a SIP, the section would not have any 
practical utility in the statutory scheme. The EPA's interpretation of 
the relationship between sections 126 and 110 is supported by the 
legislative history of the amendments to the CAA which added section 
126. In adopting the section 126 remedies, Congress explained that the 
petition process was intended to provide an avenue for relief separate 
from the 110(a)(2)(D) SIP procedure and that it was intended to 
expedite, not delay, resolution of interstate pollution conflicts.
    The EPA's interpretation of the ``prohibition'' referred to in 
section 126 is also consistent with the language of section 
110(a)(2)(D)(ii), which requires states to include in their SIPs 
provisions necessary to ensure compliance with sections 126 and 115 of 
the CAA, which relate to interstate transport and international 
transport of pollution, respectively. States are required to submit to 
the EPA such SIPs no later than 3 years after promulgation of a new or 
revised NAAQS. 42 U.S.C. 7410(a)(1). Thus, pursuant to section 
110(a)(2)(D)(ii), any emission limits and compliance schedules issued 
by the Administrator under section 126 prior to that deadline must be 
incorporated into the section 110(a)(2)(D) SIP submission for the state 
in which a source subject to such limits is located. Accordingly, the 
statute anticipates that the Administrator may address a section 126 
petition prior to the deadline for the initial submission of a section 
110(a)(2)(D) SIP.
    If Congress had intended to limit the EPA's authority to act on 
section 126 petitions until after the deadline for states to submit 
110(a)(2)(D) SIPs, it could have included such a restriction. However, 
the plain language of the statute does not clearly require this 
interpretation. Rather, the statute requires the EPA to address a 
section 126 petition within 60 days after receipt.\3\ Since the statute 
establishes firm deadlines for action on section 126 petitions, it does 
not provide an exception for petitions submitted prior to the good 
neighbor SIP submission deadline, and it provides a mechanism for 
incorporating reductions required in response to section 126 petitions 
into the state SIPs; the EPA believes it does not have discretion to 
delay action on a section 126 petition just because the state SIP 
submission deadline has not yet passed.
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    \3\ This deadline can be extended by up to 6 months pursuant to 
section 307(d)(10).
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    The EPA's interpretation of sections 110 and 126 in this context is 
also reasonable as it is consistent with the EPA's interpretation of 
these sections in two rulemakings issued in May 1999 and January 2000 
which concluded that each section of the Act provides an alternative 
avenue for relief. Findings of Significant Contribution and Rulemaking 
on Section 126 Petitions for Purposes of Reducing Interstate Ozone 
Transport, 64 FR 28250 (May 25, 1999); Findings of Significant 
Contribution and Rulemaking on Section 126 Petitions for Purposes of 
Reducing Interstate Ozone Transport, 65 FR 2674 (Jan. 18, 2000). NJDEP 
has, in this case, sought relief via section 126 from the interstate 
transport of pollution that is significantly

[[Page 69055]]

contributing to nonattainment within the state, and the EPA is 
obligated to address NJDEP's petition pursuant to the requirements of 
the Act.

B. Summary of Comments and Responses Regarding Legal Authority

    Comment: Several commenters argue that the statutory text is 
unambiguous in requiring that states be permitted to submit their 
infrastructure SIPs addressing the transport requirements of section 
110(a)(2)(D) before a section 126 petition can be filed.
    The commenters primarily argue that this interpretation is 
compelled because a section 126 petition may only be filed to complain 
of a violation of a section 110(a)(2)(D) SIP where a state has failed 
to adequately enforce its own plan. Accordingly, the commenters argue 
that there is no prohibition of transport emissions absent an approved 
SIP. The operative language in section 126 is that a petition may be 
granted where there is ``a violation of the prohibition of'' section 
110(a)(2)(D)(i). The commenters argue that ``prohibition'' referred to 
in section 126 is not on the act of emitting or contributing to 
transboundary nonattainment. Rather, the commenters assert, the 
prohibition is against emitting at levels that violate the limits 
imposed by the SIP regulations promulgated in response to the 
requirements of the CAA.
    Some of these commenters also suggest that a section 126 petition 
would be justified where a state fails to meet its SIP revision 
obligations under section 110(a)(2)(D). These commenters therefore 
argue that a section 126 petition may not be filed until the state 
fails to meet its deadline to file a SIP addressing its transport 
obligations with respect to the new or revised NAAQS.
    Response: The EPA does not agree that the interpretation posited by 
the commenters is reasonable much less compelled by the statutory text. 
Nothing in the statutory language in section 126 prohibits a downwind 
state from filing a section 126 petition until after the upwind state, 
in which the source or sources are located, has submitted, or is 
required to submit, a section 110(a)(2)(D) SIP to the EPA for approval. 
The commenters have not identified any statutory provision that so 
limits a downwind state's rights. Rather, the right of a state to file 
a section 126 petition does not have any time limitation, and the EPA 
is required to act quickly whenever presented with such a petition. The 
commenters' arguments that a section 126 petition cannot be filed, or a 
section 126 finding cannot be made, before the 110(a)(2)(D) SIP 
submission deadline passes are policy arguments with no basis in the 
statutory text. Instead, as discussed below, the statutory text, the 
structure of the CAA, and the legislative history all support the EPA's 
interpretation of the Act as creating, in sections 110 and 126, two 
independent means of controlling transboundary emissions and find no 
support for the argument that one should be prioritized over the other.
    Moreover, the plain language of the statute does not clearly define 
``prohibition'' to mean a SIP provision that sets emissions limits to 
address transboundary air pollution. Rather, the EPA believes that the 
better interpretation, in light of the structure of the CAA and its 
legislative history, is that the ``prohibition'' referred to in section 
126 is the actual, functional prohibition on transboundary air 
pollution contained in section 110(a)(2)(D)(i).
    The commenters' interpretation of the ``prohibition'' referred to 
in section 126 would render the relief provided by a section 126 
petition process essentially meaningless. If a source is emitting in 
violation of an emission limitation in a SIP, there is no question that 
the source is in violation of the SIP. The language in section 126 
stating that ``it shall be a violation of * * * the applicable 
implementation plan'' for a source to emit in violation of the 
prohibition of section 110(a)(2)(D) serves no legal purpose where the 
source is already directly violating a SIP requirement. By contrast, 
under the EPA's interpretation, section 126 deems a source's emissions 
to be a violation of the applicable SIP (as well as of section 126) 
whenever the emissions significantly contribute to nonattainment 
downwind or interferes with maintenance of any NAAQS. This 
interpretation gives legal effect to the language in section 126 and is 
consistent with Congress' purpose of providing a tool for downwind 
states and the EPA to use to impel upwind sources to reduce transported 
emissions even where a SIP may not yet directly regulate such 
emissions.
    Moreover, the EPA's interpretation of section 126 gives it a 
purpose independent of the other remedies available under the CAA. 
Under section 113, upon finding that any person is in violation of any 
requirement of an approved SIP, the EPA has the authority to enforce 
the requirement by issuing an order to comply, issuing an 
administrative penalty order, or bringing a civil action. In addition, 
any person (which includes states) may bring a citizen suit against any 
person in violation of any requirement of an approved SIP, independent 
of the EPA action. Section 304(a), (f); see also section 302. These 
provisions provide more direct and likely quicker recourse against a 
source that is violating its SIP-imposed emission limits than the 
section 126 petition process would. Thus, there is no need to have a 
petition, public hearing, and EPA determination pursuant to section 126 
simply to enforce existing SIP limits. By contrast, using the section 
126 petition process where transboundary emissions are not yet being 
controlled by an upwind state serves the unique role of allowing a 
downwind state to force the EPA's consideration of the problem and 
potentially achieve emissions reductions directly from sources, without 
the need to depend on action by the upwind state.
    The EPA's interpretation of the relationship between sections 126 
and 110 is expressly supported by the legislative history of the CAA. 
In adopting the section 126 remedies, Congress explained that the 
petition process was intended to provide an avenue for relief separate 
from the section 110(a)(2)(D) SIP procedure:

    This petition process is intended to expedite, not delay, 
resolution of interstate pollution conflicts. Thus, it should not be 
viewed as an administrative remedy which must be exhausted prior to 
bringing suit under section 304 of the act. Rather, the committee 
intends to create a second and entirely alternative method and basis 
for preventing and abating interstate pollution. The existing 
provision prohibiting any stationary source from causing or 
contributing to air pollution which interferes with timely 
attainment or maintenance or [sic] a national ambient air standard 
(or a prevention of significant deteriorating [sic] or visibility 
protection plan) in another state is retained. A new provision 
prohibiting any source from emitting any pollutant after the 
Administrator has made the requisite finding and granted the 
petition is an independent basis for controlling interstate air 
pollution.

H. Rep. 95-294 at 305, reprinted in 1977 Legislative History at 2798. 
Nothing in the legislative history suggests, as the commenters assert, 
that the section 126 remedy is dependent on the section 110 SIP 
procedure. Rather, this language clearly indicates that Congress 
intended sections 110 and 126 to operate as independent means of 
controlling transboundary emissions and that it did not intend to 
prioritize one means of control over the other. Accordingly, there is 
no basis in the legislative history to support the commenters' argument 
that a state does not have the right to submit a section 126 petition 
until after the deadline to submit a section 110(a)(2)(D) SIP has 
passed. To the contrary, the legislative history supports the 
conclusion that Congress did not intend to impose any limitation

[[Page 69056]]

tied to the section 110(a)(2)(D) SIP procedure on when a state may 
submit a section 126 petition after a new or revised NAAQS is 
promulgated.
    Moreover, Congress recognized in adopting all of the interstate 
transport provisions in the CAA that the interstate pollution problem 
stems from inadequate limits on transported emissions, and not 
inadequate compliance with adequate SIP requirements. This 
characterization of the problem is supported by the numerous 
descriptions of the interstate pollution problem in the 1977 
legislative histories, all of which explicitly or implicitly refer to 
the lack of upwind limitations and none of which mentions sources' 
violation of upwind SIP limits. See, e.g,. S. Comm. on Envt. and Public 
Works, Clean Air Act Amendments of 1977, S. Rep. 95-127, 95th Cong., 
1st Sess. 41 (1977), reprinted in 3 1977 Legislative History at 1415 
(noting that the 1970 Act failed to specify any abatement procedure if 
a source in one state emitted air pollutants that adversely affected 
another state, and ``[a]s a result, no interstate enforcement actions 
have taken place, resulting in serious inequities among several States, 
where one State may have more stringent implementation plan 
requirements than another state''); H. Rep. 95-294, 95th Cong., 1st 
Sess. at 304 (1977), reprinted in 4 1977 Legislative History at 2798 
(``[A]n effective program must not rely on prevention or abatement 
action by the State in which the source of the pollution is located, 
but rather by the state (or residents of the State) which receives the 
pollution and the harm, and thus which has the incentive and need to 
act.''). It is reasonable to assume that Congress intended to create a 
tool that would attack the problem Congress recognized. This supports 
the conclusion that Congress intended section 126 to provide an 
alternate means to compel compliance with the prohibition in section 
110(a)(2)(D) where upwind states are not controlling transboundary 
emissions, and not where sources are violating adequate SIP provisions.
    The interpretation that the EPA adopts here is also consistent with 
its historical interpretation of section 126. The EPA previously 
interpreted this section in two rulemakings issued in 1999 and 2000, 
wherein commenters challenged the EPA's authority, in light of a 
pending SIP call, to grant a number of section 126 petitions that 
sought to mitigate the transport of nitrogen oxides (NOX) 
from downwind states that were significantly contributing to ozone 
nonattainment problems in the petitioning states. 64 FR 28250; 65 FR 
2674. In both rulemakings, the EPA interpreted the relationship between 
sections 110 and 126 consistent with the EPA's interpretation here, 
concluding that the ``prohibition'' referred to in section 126 is the 
functional prohibition of section 110(a)(2)(D)(i), as opposed to an 
emissions limitation contained in a state's SIP, and that the section 
110(a)(2)(D) SIP process and the section 126 petition process are 
independent and alternative means of addressing impermissible 
interstate transport.
    Both rulemakings were challenged in the DC Circuit in Appalachian 
Power Co. v. EPA, 49 F.3d 1032 (2001), on the theories that the agency 
was required to refrain from making any section 126 findings while the 
SIP call was ongoing and that the doctrine of ``cooperative 
federalism'' embodied in the Act imposed a constraint on the EPA's 
ability to act before the section 110 process was complete. Id at 1045. 
The court deferred to the EPA's interpretation of the relationship 
between sections 110 and 126, holding that there is no inherent 
conflict in acting on a section 126 petition during the same period 
that a state has to develop a SIP submission: ``It is entirely 
reasonable for the EPA to regard a state that is under a legal 
obligation to revise its plan as being, in the meantime, in violation 
of a functional prohibition.'' Id. at 1046. The court explained that 
the petitioners' interpretation of section 126 would compromise three 
critical provisions of section 126:
    1. The requirement that source operate no more than 3 years after 
finding of contribution to downwind nonattainment;
    2. The fact that ``relief does not depend upon any action by the 
upwind states, as is necessary for a SIP revision''; and
    3. The fact that relief under section 126 is independent of the 
discretionary policy preferences of the EPA, as the agency is required 
to act upon a petition within 60 days.

Id. The court noted that the EPA's interpretation retains all three 
aspects of the statutory requirements.
Id. The court therefore concluded that ``[b]ecause it is reasonable, 
and because the `Congress provided both [Sec. Sec.  110 and 126] 
without indicating any preference for one over the other,' * * * the 
EPA's conclusion that these two provisions operate independently merits 
our deference under Chevron step two.'' Id. at 1048 (quoting 65 FR at 
2680/1).

    Thus, the EPA believes that the commenters' interpretation of 
section 126 is unreasonable and inconsistent with the legislative 
history, the EPA's past interpretations, and court rulings upholding 
those interpretations. In particular, the commenters' interpretation 
would render the relief provided by the section 126 petition process 
duplicative and unnecessary. The EPA's interpretation, on the other 
hand, gives legal effect to the language in section 126 and is 
consistent with Congress' purpose of providing an independent tool for 
a downwind states and the EPA to use to impel upwind sources to reduce 
transported emissions. The EPA believes this matter is clearly resolved 
by reference to the terms of the provision itself, so that under the 
first step of the Chevron analysis, no further inquiry is needed. If, 
however, it were concluded that the provision is ambiguous on this 
point, the EPA believes that, under the second step in the Chevron 
analysis, then the EPA should be given deference for any reasonable 
interpretation, as courts have given with respect to prior 
interpretations of section 126. Interpreting section 126 to refer to a 
functional prohibition on emissions and to preserve a state's right to 
file a section 126 petition is reasonable for the reasons described 
above.
    Comment: Several commenters argue that the EPA is turning to 
section 126 as a ``first resort'' for implementing the new NAAQS and 
that we are substituting the EPA's judgment for Pennsylvania's 
regarding the appropriate control strategy for Portland. The commenters 
contend that revising Pennsylvania's SIP is a usurpation of state 
discretion and that the SIP process would be superfluous if we allowed 
petitions to be filed so close on the heels of new or revised NAAQS. 
The commenters believe that Congress intended states to have primary 
responsibility for implementing a new or revised NAAQS. They contend 
that the EPA's interpretation of section 126 places priority on 
interstate transport over intrastate control of NAAQS attainment.
    Response: We respond by noting that the upwind state still retains 
its obligation to develop a SIP and implement the NAAQS. Applying 
section 126 independent of an upwind state's failure to act under 
section 110(a)(2)(D) does not impermissibly pressure upwind states to 
select certain control measures. The EPA acknowledges that because the 
section 126 findings precede any required state action, when states are 
eventually required to submit SIPs to control interstate transport, one 
of the largest sources of emissions will already be subject to emission 
control

[[Page 69057]]

requirements, and, depending upon the timing, may have already invested 
in controls. Yet this is not a legal constraint on states' choices--it 
is the reality that, over time, conditions change and different policy 
choices become more or less attractive for a variety of reasons. States 
would still be able to choose to regulate other sources, but depending 
upon the timing, the option of obtaining emission reductions from 
sources that have already invested in emission controls or have already 
reduced emissions may be more attractive on policy and economic grounds 
than regulating those sources otherwise would have been. There is a 
vast difference between, on one hand, the EPA prescribing a particular 
emissions control choice that states must adopt, and on the other, 
taking action required under the CAA to regulate sources directly with 
the possible effect of making certain future emissions control choices 
by some states more or less appealing.
    Such a potential future effect on the regulatory environment cannot 
override the obligation that the EPA act on state petitions under 
section 126. We do not believe it would be reasonable to conclude that 
the EPA can take no action under an independent mandate of the statute 
to respond to petitions submitted by downwind states facing their own 
time constraints and pressures to meet air quality standards, just to 
preserve the relative attractiveness of a variety of options for 
control of SO2 in the upwind states required under another 
provision of the CAA. The cooperative federalism principles of the CAA 
do not require the EPA to withhold federal action under section 126 
until states have been required to and failed to submit SIPs. It is 
perfectly reasonable for Congress to have established section 126 as an 
alternative mechanism under the CAA to address the interstate pollution 
problem, just as it did again in adopting sections 176A and 184. To 
provide alternatives, the various interstate transport provisions are 
necessarily different from each other and from other provisions of the 
Act, but that does not make them inconsistent with other provisions of 
the Act. Thus, simply because the EPA will have imposed certain 
requirements on Portland does not mean that Pennsylvania no longer has 
any discretion in crafting its SIP submission with respect to NAAQS 
compliance anywhere in the state. Pennsylvania can take into 
consideration the controls that Portland chooses to implement when 
creating its own attainment plan, just as it would take into 
consideration controls implemented at any other source.
    The court in Appalachian Power Co. v. EPA specifically addressed 
this concern that action on the section 126 petition before the SIP 
submissions were due would restrict the states' discretion to fashion 
their own plan for complying with the NAAQS: ``SIP development, like 
any environmental planning process, commonly involves decisionmaking 
subject to various legal constraints. That Sec.  126 imposes one such 
limitation--and it is surely not the only independent provision of 
federal law to do so--does not affect a state's discretion under Sec.  
110.'' 49 F.3d at 1047.
    Finally, as explained in detail above, Congress intended sections 
110 and 126 to operate as independent and alternate means to address 
transboundary pollution, and indicated no preference for one means of 
compelling compliance over the other. Thus, the EPA's action on this 
section 126 petition does not prioritize the control of interstate 
pollution over a state's control of intrastate pollution. Rather, it 
gives legal effect to section 126, consistent with the structure of the 
CAA and the legislative history, by providing a tool for downwind 
states to use to impel upwind sources to reduce transported emissions.

IV. Summary and Assessment of the Modeling and Other Data Relevant to 
the EPA's Proposed Finding

A. Summary of the Modeling for the Proposed Rule

    NJDEP's section 126 petition contained dispersion modeling results, 
based on both the CALPUFF \4\ and AERMOD dispersion models, that NJDEP 
relied upon to show that emissions from Portland, alone, caused 
downwind violations of the 1-hour SO2 NAAQS in New Jersey. 
Given the magnitude of the modeling violations, which were nearly seven 
times the 1-hour SO2 NAAQS based on AERMOD modeling of 
maximum allowable emissions, and the fact that significant exceedances 
of the NAAQS were also shown based on modeling of estimated actual 
emissions, the EPA concluded that the NJDEP had clearly shown that 
SO2 emissions from Portland cause violations of the 1-hour 
SO2 NAAQS in New Jersey.
---------------------------------------------------------------------------

    \4\ CALPUFF is a non-steady-state puff dispersion model that was 
originally developed for the California Air Resources Board.
---------------------------------------------------------------------------

    The EPA also modeled the emissions from Portland using the AERMOD 
dispersion model and determined that the modeled concentrations from 
Portland, when combined with the relatively low background 
concentrations, cause violations of the 1-hour SO2 NAAQS in 
Morris, Sussex, Warren and Hunterdon Counties in New Jersey.\5\ This 
section discusses the key modeling issues that arise in making that 
determination, and how the EPA is responding to comments we received on 
those issues. We also note that this modeling is used not only to 
characterize the NAAQS violations, but, as discussed in section V, it 
is also used to determine the appropriate remedy to address such 
violations.
---------------------------------------------------------------------------

    \5\ The EPA modeling analysis is detailed in the proposed rule 
Air Quality Modeling Technical Support Document, available in Docket 
ID EPA-HQ-OAR-2011-0081-0026.
---------------------------------------------------------------------------

1. Modeling Analysis in NJDEP's Section 126 Petition
a. Model Selection
    Model selection was one of the key issues that the EPA addressed in 
support of this rule given the critical role played by dispersion 
modeling both in relation to a finding under a section 126 petition 
that a source significantly contributes to nonattainment and/or 
interferes with maintenance of the 1-hour SO2 NAAQS in a 
neighboring state, and in relation to the determination of an 
appropriate remedy to address such a finding. As summarized in the 
proposed rule and documented in more detail in the EPA's proposed rule 
Air Quality Modeling Technical Support Document, NJDEP included 
modeling results based on both the CALPUFF and AERMOD dispersion models 
with its section 126 petition. The importance of this issue is further 
highlighted by the fact that the maximum 99th percentile of the daily 
maximum 1-hour modeled SO2 concentrations based on CALPUFF 
was about 2.5 times higher than the maximum 99th percentile of the 
daily maximum 1-hour modeled concentrations based on AERMOD. 
Consequently, a much more stringent remedy would be required to address 
such a finding based on CALPUFF modeling than based on AERMOD modeling.
    The NJDEP acknowledged that AERMOD is the preferred model under the 
EPA's ``Guideline on Air Quality Models,'' published as Appendix W to 
40 Code of Federal Regulations (CFR) Part 51, for near-field 
applications such as this, but suggested that the use of CALPUFF may be 
appropriate under the alternative model provisions in Section 3.2.2b of 
Appendix W. Section 3.2 of Appendix W lists three separate conditions 
under which an alternative model may be approved for use:

[[Page 69058]]

    (1) If a demonstration can be made that the model produces 
concentration estimates equivalent to the estimates obtained using a 
preferred model;
    (2) If a statistical performance evaluation has been conducted 
using measured air quality data and the results of that evaluation 
indicate the alternative model performs better for the given 
application than a comparable model in Appendix A of Appendix W; or
    (3) If the preferred model is less appropriate for the specific 
application, or there is no preferred model.
    The NJDEP modeling documentation suggested that NJDEP's use of the 
CALPUFF model in support of this petition was based on condition (2) of 
Section 3.2.2b, claiming to have shown that CALPUFF ``performed better 
and produced predictions of greater accuracy than AERMOD'' for this 
application. NJDEP also claimed that the use of CALPUFF is more 
appropriate for this specific application due to the complex winds 
addressed in Section 7.2.8 of Appendix W and is therefore justified 
under condition (3) of Section 3.2.2b.
    The section 126 petition referenced a CALPUFF model validation 
study based on the Martin's Creek field study database, submitted by 
NJDEP with an earlier section 126 petition, as demonstrating that 
``CALPUFF performed better and produced predictions of greater accuracy 
than AERMOD'' for this application.\6\
---------------------------------------------------------------------------

    \6\ See Letter from Bob Martin, Commissioner, New Jersey 
Department of Environmental Protection (NJDEP) to Lisa P. Jackson, 
Administrator, USEPA (September 13, 2010), Section IV, page 5. 
Docket ID No. EPA Docket, EPA-HQ-OAR-2011-0081-009.
---------------------------------------------------------------------------

    At proposal, the EPA included a detailed assessment of the NJDEP 
CALPUFF validation study as Appendix A of the proposed rule Air Quality 
Modeling TSD, and concluded that NJDEP had not adequately justified the 
use of CALPUFF in this application under either conditions (2) or (3) 
of Section 3.2.2b of Appendix W. The EPA further asserted that AERMOD 
is the most appropriate model for this application. Our assessment of 
the CALPUFF validation study identified several aspects of NJDEP's 
validation methodology that deviated from the EPA's Protocol for 
Determining the Best Performing Model,\7\ which undermined the 
integrity of the evaluation results. In addition, we cited the ``weight 
of evidence'' regarding AERMOD model performance which is based on 
evaluations for a total of 17 field study databases as compared to 
NJDEP's CALPUFF validation study which is the only near-field 
evaluation of CALPUFF model performance that the EPA is aware of that 
included CALMET-generated 3-dimensional wind fields. We also pointed to 
the fact that the 1-hour, 3-hour and 24-hour quantile-quantile (Q-Q) 
plots of modeled versus observed concentrations for AERMOD and CALPUFF 
included in the NJDEP validation study suggested that the performance 
of the CALPUFF and AERMOD models was very similar for this database, 
with both models exhibiting generally good agreement with observations, 
but with AERMOD showing slightly better overall agreement than CALPUFF. 
These clear visual comparisons of model performance are difficult to 
reconcile with NJDEP's assertion that CALPUFF performed better than 
AERMOD.
---------------------------------------------------------------------------

    \7\ Protocol for Determining the Best Performing Model. EPA-454/
R-92-025 (1992). U.S. Environmental Protection Agency, Research 
Triangle Park, NC, available at: https://www.epa.gov/ttn/scram/guidance/guide/modleval.zip.
---------------------------------------------------------------------------

b. Meteorological Data
    Another key component of the dispersion modeling analysis is the 
meteorological data. The EPA based the AERMOD modeling in support of 
the proposed rule on 1 year of Portland site-specific meteorological 
data available for July 1993 through June 1994. The site-specific 
meteorological data were collected from a 100-meter instrumented tower 
and Sound Detection and Ranging instrument (SODAR), located about 2.2 
kilometers west of Portland. Based on a review of the data, we 
determined that the Portland meteorological data from 1993-94 meet the 
basic criteria for representativeness under Section 8.3.3 of Appendix 
W, and therefore can be considered as site-specific data for purposes 
of modeling impacts from the elevated stacks for Portland units 1 and 
2. The 1993-94 data also meet the minimum criterion for the length of 
meteorological data record of at least 1 year of site-specific 
meteorological data recommended in Section 8.3.1.2 of Appendix W. 
However, the difference of about 100 meters in the base elevation for 
the meteorological tower versus the stack base elevation raised 
concerns regarding how the meteorological data were input to the AERMOD 
model in the NJDEP modeling analysis given that the stack heights for 
units 1 and 2 are about 122 meters and that plume heights of concern 
for units 1 and 2 are about 200 to 400 meters above stack base.
    The AERMOD modeling submitted by NJDEP used the measurement heights 
above local ground at the tower location for the meteorological data 
input to the model, effectively assuming that the measured profiles of 
wind, temperature and turbulence are ``terrain-following.'' Without 
adjusting for the difference in base elevation of about 100 meters 
between the meteorological data and the stacks, wind speeds are likely 
to be biased high and the wind directions may not be representative of 
plume heights relative to stack base. A review of the raw 
meteorological data files for Portland also revealed the fact that 
[sigma]w (vertical turbulence) data were available from the 
SODAR, but had not been used in the AERMOD modeling submitted with 
NJDEP's section 126 petition. Based on the analyses that are described 
in more detail in the EPA proposed rule Air Quality Modeling TSD, the 
EPA concluded that the representativeness of the Portland 
meteorological data would be improved by incorporating some adjustments 
to the measurement heights from the SODAR data and the inclusion of the 
[sigma]w data collected from the SODAR.
2. The EPA's Modeling Analysis To Quantify Significant Contribution
    In the EPA AERMOD modeling analysis, thousands of receptors were 
placed in New Jersey to determine the area of maximum concentration 
from Portland's emissions in order to quantify Portland's significant 
contribution to nonattainment in New Jersey. A design value 
concentration was calculated for each receptor for comparison to the 
NAAQS. The design value concentration is equal to the 99th percentile 
(4th-highest) of the annual distribution of daily maximum 1-hour 
SO2 concentrations. All receptors with modeled design value 
concentrations that are greater than the NAAQS [196.2 micrograms per 
cubic meter (ug/m\3\)] \8\ are determined to be nonattainment 
receptors.
---------------------------------------------------------------------------

    \8\ The 1-hour SO2 NAAQS is 75 ppb. For comparison to 
dispersion modeling results in units of ug/m\3\, the NAAQS can be 
expressed as 196.2 ug/m\3\, assuming reference temperature and 
pressure.
---------------------------------------------------------------------------

    The EPA proposed to define Portland's significant contribution to 
nonattainment and interference with maintenance as those emissions that 
must be eliminated to bring the downwind receptors in New Jersey 
affected by Portland into modeled attainment in the analysis year. 
While this approach would not be appropriate in every circumstance, the 
EPA believes it is appropriate where, as here, the source's emissions 
are sufficient on their own to cause downwind NAAQS violations and 
background levels of the relevant pollutant are relatively low. The EPA 
therefore developed a

[[Page 69059]]

methodology to identify the reductions necessary to bring the downwind 
receptors into attainment.
    To quantify the emissions that constitute Portland's significant 
contribution, the EPA identified the level of emissions that need to be 
reduced to ensure that no modeled concentration within the affected 
area (in New Jersey) exceeds the level of the NAAQS (i.e., the 99th 
percentile of the daily maximum 1-hour average of 196.2 ug/m\3\).
    The EPA also analyzed the modeling results to determine the 
appropriate emissions reductions that were needed to eliminate 
``interfere with maintenance.'' In addition to nonattainment receptors, 
the EPA also attempted to identify receptors that are modeled to be 
attainment but due to variability in meteorology or emissions might be 
at risk for nonattainment. Due to the high modeled concentrations from 
Portland's emissions, all of the downwind modeled receptors in the 
final modeled receptor grid in New Jersey are modeled to be 
nonattainment. In this application, it was not necessary to expand the 
modeling grid to identify additional nonattainment or ``maintenance 
only'' receptors because the modeling domain was focused on the 
receptors with the maximum impact from Portland. Therefore, the EPA did 
not identify any ``maintenance only'' receptors.
    In the proposal, the EPA considered whether Portland should be 
required to make additional reductions, above and beyond those required 
to eliminate its significant contribution to nonattainment, to ensure 
that it does not interfere with maintenance of the 1-hour 
SO2 NAAQS in violation of the prohibition in section 
110(a)(2)(D). We identified an approach that we believe is appropriate 
for these specific circumstances. Among other things, we considered the 
nature of the modeling used to determine the appropriate remedy and the 
potential for actual SO2 concentrations in New Jersey to be 
higher than those modeled. In the proposal, the EPA determined there is 
no indication that concentrations higher than those modeled from 
Portland would be likely to occur at nonattainment and/or maintenance 
receptors or anywhere else in New Jersey. This was based on the 
following facts:
    1. There is only 1 year of site-specific meteorology available, 
such that we were not able to explicitly examine the impact of year-to-
year variability of meteorology on downwind modeled concentrations.\9\
---------------------------------------------------------------------------

    \9\ Due to constraints on data availability, our analysis is 
appropriate in this instance; however, nothing here is intended to 
suggest that, where sufficient data are available to examine year-
to-year variability, this should not be a relevant factor.
---------------------------------------------------------------------------

    2. The remedy modeling used maximum allowable emissions from 
Portland. Since these are the highest emissions that are allowed to be 
emitted by the facility, higher concentrations could not be expected to 
occur in New Jersey due to the variability of emission from Portland.
    3. In the modeling analysis, we used background concentrations that 
varied by season and hour of day based on the 3-year average of the 
99th percentile of the distribution of hourly SO2 
concentrations in the area, which represents the high end of the 
distribution of monitored background concentrations. The background 
concentration accounts for contributions from other SO2 
sources. As demonstrated by NJDEP's trajectory analysis,\10\ it is 
likely that SO2 impacts from Portland contributed to some of 
the high monitored concentrations at the Chester, New Jersey, monitor 
used to represent the background concentrations, which is located about 
34 kilometers east-southeast of Portland. Although use of the 99th 
percentile values by season and hour of day from the Chester, New 
Jersey, monitor eliminated some of the peak hourly SO2 
concentrations, the background concentrations are still likely to be 
somewhat conservative (high) to account for variability that otherwise 
cannot be quantified.
---------------------------------------------------------------------------

    \10\ See Trajectory Analysis of High Sulfur Dioxide Episodes at 
the Chester, NJ Monitor. Bureau of Technical Services, Division of 
Air Quality, New Jersey Department of Environmental Protection. July 
30, 2010. Submitted to USEPA as Exhibit 4 of the September 13, 2010 
Supplement to New Jersey's May 12, 2010 Petition Pursuant to Section 
126 of the Clean Air Act, 42 U.S.C. 7426. Docket ID No. EPA Docket, 
EPA-HQ-OAR-2011-0081-008.
---------------------------------------------------------------------------

    It was therefore reasonable to conclude, under the circumstances, 
that any remedy that eliminates the significant contribution to 
nonattainment from Portland also eliminates its interference with 
maintenance with respect to year-to-year variability in emissions and 
meteorology. The EPA therefore proposed to find that compliance by 
Portland with the proposed emission limits will bring it into 
compliance with the prohibition on emissions that significantly 
contribute to nonattainment of the 1-hour SO2 NAAQS as well 
as with the prohibition on emissions that interfere with maintenance in 
a downwind area. The EPA requested comments on our modeling methodology 
and meteorological data adjustments.

B. Public Comments Related to the Modeling

    We received many public comments related to the modeling that was 
used to support the finding that SO2 emissions from Portland 
contribute significantly to nonattainment and interfere with 
maintenance of the 1-hour SO2 NAAQS in New Jersey. Some of 
the main comments and the EPA's responses related to model selection, 
meteorological data, emissions and source characteristics, and 
background concentrations are summarized below, with further details 
provided in the Response to Comments document.
1. Model Selection
    Comments: We received several comments supporting the EPA's 
conclusion that AERMOD is the appropriate dispersion model for this 
petition, and that also supported the EPA's overall assessment that 
NJDEP's CALPUFF validation study failed to demonstrate that CALPUFF 
performs better for this application than AERMOD. One commenter (NJDEP) 
believes that the modeling in support of the section 126 petition 
should be based on CALPUFF, and provided detailed comments on the EPA 
assessment of the CALPUFF validation study.
    Response: As discussed in greater detail in the final rule Air 
Quality Modeling technical support document (final rule Modeling TSD), 
the EPA review of NJDEP's comments related to our assessment of the 
CALPUFF validation study has identified additional deficiencies with 
the study that further undermine NJDEP's conclusion that ``CALPUFF 
performed better and produced predictions of greater accuracy than 
AERMOD'' for this application. One of these deficiencies that came to 
light upon closer examination of the CALPUFF modeling files for the 
validation study is that NJDEP used the ``ISC Type'' option for 
building downwash in CALPUFF instead of the PRIME \11\ downwash option 
when applying CALPUFF for the Martin's Creek validation study, although 
the CALPUFF input file

[[Page 69060]]

included the necessary building input parameters to run the PRIME 
option. The AERMOD modeling results for Martin's Creek used for 
comparison were based on the PRIME downwash algorithm. While building 
downwash associated with the cooling towers at Martin's Creek exhibited 
only a modest influence on results based on AERMOD evaluations, it is 
important enough to be treated properly in the model evaluation, and 
the EPA concludes that the PRIME downwash option should have been used 
in the CALPUFF modeling since AERMOD's promulgation effectively 
established the PRIME algorithm as the ``preferred'' downwash algorithm 
for near-field applications. NJDEP's CALPUFF validation report 
identifies that the ``ISC type'' downwash option was used in the table 
of CALPUFF inputs (the MBDW parameter in Table 8.2), but provides no 
explanation or justification for not using the PRIME downwash option. 
As described in more detail in the final rule Modeling TSD, the 
inclusion of the PRIME downwash option in CALPUFF resulted in a greater 
tendency for CALPUFF to overestimate concentrations at Martin's Creek 
as compared to the ``ISC-Type'' downwash option, with some 
deterioration in model performance metrics.
---------------------------------------------------------------------------

    \11\ The ``ISC Type'' building downwash option in CALPUFF refers 
to the Huber-Snyder and Schulman-Scire algorithms that are 
incorporated in the Industrial Source Complex Short Term (ISCST3) 
model. The PRIME downwash option refers to the ``Plume Rise Model 
Enhancements'' algorithms that were initially incorporated into a 
revised version of ISCST3 called ISC-PRIME, and were later 
incorporated into the AERMOD model prior to its promulgation as the 
EPA-preferred model for near-field applications, replacing ISCST3, 
in 2005.
---------------------------------------------------------------------------

    Additional evidence supporting the EPA's determination that AERMOD 
is a more appropriate model for this application than CALPUFF was 
provided by an EPA analysis of high modeled SO2 
concentrations versus high observed SO2 concentrations at 
the Columbia Lake Wildlife Management (Columbia) air quality monitor 
located in New Jersey about 2 kilometers northeast of Portland. The EPA 
compared the observed SO2 data from September 2010 through 
September 2011 to modeled concentrations from AERMOD and CALPUFF. 
Although the monitored con