
[Federal Register Volume 77, Number 146 (Monday, July 30, 2012)]
[Proposed Rules]
[Pages 44551-44555]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2012-18545]



[[Page 44551]]

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 52

[EPA-R09-OAR-2012-0398; FRL-9707-4]


Approval of Air Quality Implementation Plans; Arizona; Interstate 
Transport of Fine Particulate Matter

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.

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SUMMARY: EPA is proposing to approve a State Implementation Plan (SIP) 
revision submitted by the State of Arizona on October 14, 2009 and to 
determine that the existing SIP is adequate to address the requirements 
of section 110(a)(2)(D)(i)(I) of the Clean Air Act (CAA) for the 2006 
National Ambient Air Quality Standard (NAAQS or standard) for fine 
particulate matter (PM2.5). Section 110(a)(2)(D)(i)(I) of 
the CAA requires that each SIP contain adequate provisions to prohibit 
air emissions from adversely affecting air quality in other states 
through interstate transport. EPA is proposing to approve the SIP 
revision submitted by Arizona and to conclude that additional control 
measures in Arizona are not necessary under CAA section 
110(a)(2)(D)(i)(I) because emissions from Arizona sources do not 
contribute significantly to nonattainment or interfere with maintenance 
of the 2006 24-hour PM2.5 NAAQS in any other state. We are 
taking comments on this proposal and plan to follow with a final 
action.

DATES: Written comments must be received on or before August 29, 2012.

ADDRESSES: Submit your comments, identified by Docket ID Number EPA-
R09-OAR-2012-0398, by one of the following methods:
    1. http://www.regulations.gov: Follow the on-line instructions for 
submitting comments.
    2. Email: vagenas.ginger@epa.gov.
    3. Fax: 415-942-3964.
    4. Mail or deliver: Ginger Vagenas (AIR-2), U.S. Environmental 
Protection Agency, Region IX, 75 Hawthorne Street, San Francisco, CA 
94105-3901. Deliveries are only accepted during the Regional Office's 
normal hours of operation.
    Instructions: All comments will be included in the public docket 
without change and may be made available online at http://www.regulations.gov, including any personal information provided, 
unless the comment includes Confidential Business Information (CBI) or 
other information whose disclosure is restricted by statute. 
Information that you consider CBI or otherwise protected should be 
clearly identified as such and should not be submitted through http://www.regulations.gov or email. http://www.regulations.gov is an 
anonymous access system, and EPA will not know your identity or contact 
information unless you provide it in the body of your comment. If you 
send email directly to EPA, your email address will be automatically 
captured and included as part of the public comment. If EPA cannot read 
your comment due to technical difficulties and cannot contact you for 
clarification, EPA may not be able to consider your comment.
    Docket: Generally, documents in the docket for this action are 
available electronically at www.regulations.gov and in hard copy at EPA 
Region IX, 75 Hawthorne Street, San Francisco, California. While all 
documents in the docket are listed at www.regulations.gov, some 
information may be publicly available only at the hard copy location 
(e.g., copyrighted material, large maps), and some may not be publicly 
available in either location (e.g., CBI). To inspect the hard copy 
materials, please schedule an appointment during normal business hours 
with the contact listed in the FOR FURTHER INFORMATION CONTACT section.

FOR FURTHER INFORMATION CONTACT: Ginger Vagenas, Air Planning Office 
(AIR-2), U.S. Environmental Protection Agency, Region IX, (415) 972-
3964 vagenas.ginger@epa.gov.

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

Table of Contents

I. Background
II. The State's Submittal
III. EPA's Evaluation
IV. Proposed Action
V. Statutory and Executive Order Reviews

I. Background

A. 2006 24-Hour PM2.5 NAAQS Infrastructure Requirements

    On September 21, 2006, EPA promulgated a final rule revising the 
1997 24-hour primary and secondary NAAQS for PM2.5 from 65 
micrograms per cubic meter ([micro]g/m\3\) to 35 [micro]g/m\3\. 71 FR 
61144 (October 17, 2006).
    Section 110(a)(1) of the CAA requires each state to submit to EPA, 
within 3 years (or such shorter period as the Administrator may 
prescribe) after the promulgation of a primary or secondary NAAQS or 
any revision thereof, a SIP that provides for the ``implementation, 
maintenance, and enforcement'' of such NAAQS. EPA refers to these 
specific submissions as ``infrastructure'' SIPs because they are 
intended to address basic structural SIP requirements for new or 
revised NAAQS. For the 2006 24-hour PM2.5 NAAQS, these 
infrastructure SIPs were due on September 21, 2009.\1\ Section 
110(a)(2) includes a list of specific elements that each such plan 
submission must meet, including section 110(a)(2)(D)(i), which pertains 
to interstate transport of certain emissions.
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    \1\ The rule establishing the revised PM2.5 NAAQS was 
signed by the Administrator and publically disseminated on September 
21, 2006. Because EPA did not prescribe a shorter period for section 
110(a) ``infrastructure'' SIP submittals for these NAAQS, these 
submittals were due on September 21, 2009, three years from the 
September 21, 2006 signature date pursuant to section 110(a)(1) of 
the CAA. See 42 U.S.C. 7410(a)(1).
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    The transport SIP provisions in section 110(a)(2)(D)(i) (also 
called ``good neighbor'' provisions) require each state to submit a SIP 
that prohibits emissions that adversely affect another state in the 
ways contemplated in the statute. Section 110(a)(2)(D)(i) identifies 
four distinct elements related to the evaluation of impacts of 
interstate transport of air pollutants. In this action, EPA is 
addressing the first two elements of this section (i.e., the 
requirements in section 110(a)(2)(D)(i)(I) to prohibit emissions 
activity within a state that will significantly contribute to 
nonattainment or interfere with maintenance of the NAAQS in any other 
state) for the 2006 24-hour PM2.5 NAAQS.\2\
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    \2\ This proposed action does not address the remaining two 
elements of the transport SIP provision (in CAA section 
110(a)(2)(D)(i)(II)) regarding interference with measures required 
to prevent significant deterioration of air quality or to protect 
visibility in another state. We intend to evaluate and act upon 
Arizona's SIP submissions addressing these additional requirements 
of CAA section 110(a)(2)(D)(i) in separate rulemakings. We proposed 
action on Arizona's provisions regarding interference with other 
states' measures to prevent significant deterioration of air quality 
on June 27, 2012. See 77 FR 38239.
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    The first element of section 110(a)(2)(D)(i) requires that each SIP 
for a new or revised NAAQS contain adequate measures to prohibit any 
source or other type of emissions activity within the state from 
emitting air pollutants that will ``contribute significantly to 
nonattainment'' of the NAAQS in another state. The second element of 
CAA section 110(a)(2)(D)(i) requires that each SIP prohibit any source 
or other type of emissions activity in the state from emitting 
pollutants that will ``interfere with maintenance'' of the applicable 
NAAQS in any other state.

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B. NOX SIP Call, Clean Air Interstate Rule (CAIR) and the 
Transport Rule

    EPA has previously addressed the requirements of section 
110(a)(2)(D)(i)(I) in past regulatory actions such as the 1998 
NOX SIP call,\3\ the 2005 Clean Air Interstate Rule 
(``CAIR''),\4\ and the 2011 Transport Rule (also known as the ``Cross-
State Air Pollution Rule'' or ``CSAPR'').\5\ In the NOX SIP 
call, EPA took action to remediate emissions of nitrogen oxides 
(NOX) that significantly contributed to nonattainment of, or 
interfered with maintenance of, the then applicable ozone NAAQS through 
interstate transport of NOX and the resulting ozone.\6\ 
Through this rule, EPA evaluated whether or not the ozone-season 
NOX emissions in certain states had prohibited interstate 
impacts, and if they had such impacts, required the states to adopt 
substantive SIP revisions to eliminate the NOX emissions, 
whether through participation in a regional cap and trade program or by 
other means.\7\
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    \3\ 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,'' 63 FR 57356 
(October 27, 1998) (``NOX SIP Call'').
    \4\ See ``Rule to Reduce Interstate Transport of Fine 
Particulate Matter and Ozone (Clean Air Interstate Rule); Revisions 
to Acid Rain Program; Revisions to the NOX SIP Call,'' 70 
FR 25162 (May 12, 2005) (``CAIR'').
    \5\ See ``Federal Implementation Plans: Interstate Transport of 
Fine Particulate Matter and Ozone and Correction of SIP Approvals; 
Final Rule,'' 76 FR 48208 (August 8, 2011) (``Transport Rule'').
    \6\ See 63 FR 57356 (October 27, 1998). EPA's general approach 
to section 110(a)(2)(D) in the NOX SIP Call was upheld in 
Michigan v. EPA, 213 F.3d 663 (D.C. Cir. 2000), cert denied, 532 
U.S. 904 (2001). However, EPA's approach to interference with 
maintenance in the NOX SIP Call was not explicitly 
reviewed by the court. See North Carolina v. EPA, 531 F.3d 896, 907-
09 (D.C. Cir. 2008).
    \7\ Ibid.
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    After promulgation of the 1997 8-hour ozone NAAQS and the 1997 
PM2.5 NAAQS, EPA again recognized that regional transport 
was a serious concern throughout the eastern United States and 
therefore developed CAIR to address emissions of sulfur dioxide 
(SO2) and NOX that exacerbate ambient ozone and 
PM2.5 levels in many downwind areas through interstate 
transport.\8\ Within CAIR, EPA interpreted the term ``interfere with 
maintenance'' as part of the evaluation of whether or not the emissions 
of sources in certain states had such impacts on areas that EPA 
projected would be in violation of the NAAQS unless actions were taken 
by upwind states to reduce SO2 and NOX emissions. 
Through CAIR, EPA again required states that had such interstate 
impacts to adopt substantive SIP revisions to eliminate the 
SO2 and NOX emissions, whether through 
participation in a regional cap and trade program or by other means.
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    \8\ See 70 FR 25162 at 25263-69 (May 12, 2005).
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    In 2008, the U.S. Court of Appeals for the D.C. Circuit found that 
CAIR and the related CAIR federal implementation plans were unlawful. 
North Carolina v. EPA, 531 F.3d 896 (D.C. Cir. 2008), modified on 
rehearing, North Carolina v. EPA, 550 F.3d 1176, 1178 (D.C. Cir. 2008). 
Among other issues, the court held that EPA had not correctly addressed 
the second element of section 110(a)(2)(D)(i)(I) in CAIR and noted that 
``EPA gave no independent significance to the `interfere with 
maintenance' prong of section 110(a)(2)(D)(i)(I) to separately identify 
upwind sources interfering with downwind maintenance.'' 531 F.3d at 
909. EPA's approach, the court reasoned, would leave areas that are 
``barely meeting attainment'' with ``no recourse'' to address upwind 
emissions sources. Id. The court therefore concluded that a plain 
language reading of the statute requires EPA to give independent 
meaning to the interfere with maintenance requirement of section 
110(a)(2)(D)(i) and that the approach used by EPA in CAIR failed to do 
so.
    To address the judicial remand of CAIR and to replace it, on August 
8, 2011, EPA published the final Transport Rule. 76 FR 48208. The 
Transport Rule addresses interstate transport pursuant to CAA section 
110(a)(2)(D)(i)(I) in the eastern United States with respect to the 
1997 8-hour ozone NAAQS, the 1997 PM2.5 NAAQS, and the 2006 
24-hour PM2.5 NAAQS.\9\ As part of this rulemaking, EPA 
specifically reexamined the section 110(a)(2)(D)(i)(I) requirements to 
prohibit emissions from sources in a state that ``contribute 
significantly to nonattainment'' or ``interfere with maintenance'' of 
the NAAQS in other states and developed an approach to identify (1) 
areas that it predicts to be violating the NAAQS, and (2) areas that it 
predicts to be close to the level of these NAAQS and therefore at risk 
to become nonattainment unless emissions from sources in other states 
are appropriately controlled. This approach starts by identifying those 
specific geographic areas for which further evaluation is appropriate 
and differentiates between areas where the concern is significant 
contribution to nonattainment as opposed to interference with 
maintenance. EPA then conducts state-specific analyses of multiple 
factors related to pollution levels at the identified ``receptors'' 
(monitoring sites) of concern to evaluate significant contribution to 
nonattainment and interference with maintenance of the NAAQS in other 
states.
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    \9\ CAIR did not address the 2006 24-hour PM2.5 
NAAQS.
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    On December 30, 2011, the U.S. Court of Appeals for the D.C. 
Circuit issued an order addressing the status of the Transport Rule and 
CAIR in response to motions filed by numerous parties seeking a stay of 
the Transport Rule pending judicial review.\10\ In that order, the 
court stayed the Transport Rule pending resolution of these petitions 
for review of the rule. The court also stated that EPA is expected to 
continue to administer CAIR in the interim until the court rules on 
these petitions for review of the Transport Rule.
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    \10\ See Order dated December 30, 2011, EME Homer City 
Generation, L.P. v. EPA (No. 11-1302 and consolidated cases) (D.C. 
Circuit).
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C. EPA Guidance

    On September 25, 2009, after the court remanded CAIR and while EPA 
was working on its replacement, EPA issued a guidance memorandum that 
provides recommendations to states for making submissions to meet the 
requirements of CAA section 110(a)(2)(D)(i) for the 2006 
PM2.5 standards (``2006 PM2.5 NAAQS 
Infrastructure Guidance'' or ``Guidance'').\11\ With respect to the 
requirement in section 110(a)(2)(D)(i)(I) to prohibit emissions that 
would contribute significantly to nonattainment of the NAAQS in any 
other state, the 2006 PM2.5 NAAQS Infrastructure Guidance 
essentially reiterated the recommendations for western states made by 
EPA in previous guidance addressing the 110(a)(2)(D)(i) requirements 
for the 1997 8-hour Ozone and 1997 PM2.5 NAAQS.\12\ The 2006 
PM2.5 NAAQS Infrastructure Guidance advised states outside 
of the CAIR region to include in their section 110(a)(2)(D)(i)(I) SIPs 
adequate technical analyses to support their conclusions regarding 
interstate pollution transport, e.g., information concerning emissions 
in the state, meteorological conditions in the state and in potentially 
impacted states, monitored ambient pollutant concentrations in the 
state and in potentially impacted states, distances to

[[Page 44553]]

the nearest areas not attaining the NAAQS in other states, and air 
quality modeling. See 2006 PM2.5 NAAQS Infrastructure 
Guidance at 3.\13\ With respect to the requirement in section 
110(a)(2)(D)(i)(I) to prohibit emissions that would interfere with 
maintenance of the NAAQS by any other state, the Guidance stated that 
SIP submissions must address this independent requirement of the 
statute and provide technical information appropriate to support the 
state's conclusions, such as information concerning emissions in the 
state, meteorological conditions in the state and in potentially 
impacted states, monitored ambient concentrations in the state and in 
potentially impacted states, and air quality modeling. See 2006 
PM2.5 NAAQS Infrastructure Guidance at 3, 4.
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    \11\ See Memorandum from William T. Harnett entitled ``Guidance 
on SIP Elements Required Under Sections 110(a)(1) and (2) for the 
2006 24-Hour Fine Particle (PM2.5) National Ambient Air 
Quality Standards (NAAQS),'' September 25, 2009.
    \12\ See Memorandum from William T. Harnett entitled ``Guidance 
for State Implementation Plan (SIP) Submission to Meet Current 
Outstanding Obligations Under Section 110(a)(2)(D)(i) for the 8-hour 
ozone and PM2.5 National Ambient Air Quality Standards,'' 
August 15, 2006.
    \13\ The 2006 PM2.5 NAAQS Infrastructure Guidance 
stated that EPA was working on a new rule to replace CAIR that would 
address issues raised by the court in the North Carolina case and 
that would provide guidance to states in addressing the requirements 
related to interstate transport in CAA section 110(a)(2)(D)(i)(I) 
for the 2006 PM2.5 NAAQS. It also noted that states could 
not rely on the CAIR rule for section 110(a)(2)(D)(i)(I) submissions 
for the 2006 24-hour PM2.5 NAAQS because the CAIR rule 
did not address this NAAQS. See 2006 PM2.5 NAAQS 
Infrastructure Guidance at 3.
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    In this action, EPA is maintaining the conceptual approach to 
evaluating interstate pollution transport under CAA section 
110(a)(2)(D)(i)(I) that the Agency provided in the 2006 
PM2.5 NAAQS Infrastructure Guidance and the Transport Rule.
    As described more fully in our Technical Support Document (TSD), 
EPA evaluated data from existing monitors over three overlapping 3-year 
periods (i.e., 2006-2008, 2007-2009, and 2008-2010) to determine which 
areas are expected to be violating the 2006 24-hour PM2.5 
NAAQS and which areas are predicted to potentially have difficulty 
maintaining attainment. In essence, if a monitoring site shows a 
violation of the 2006 24-hour PM2.5 NAAQS during the most 
recent 3-year period (2008-2010), then this monitor location is 
appropriate for evaluation for purposes of the significant contribution 
to nonattainment element of section 110(a)(2)(D)(i)(I). If, on the 
other hand, a monitoring site shows attainment of the 2006 24-hour 
PM2.5 NAAQS during the most recent 3-year period (2008-2010) 
but a violation in at least one of the previous two 3-year periods 
(2006-2008 or 2007-2009), then this monitor location is appropriate for 
evaluation for purposes of the interfere with maintenance element of 
the statute.
    By this method, EPA has identified those areas with monitors that 
are appropriate ``nonattainment receptors'' or ``maintenance 
receptors'' for evaluating whether the emissions from sources in 
another state could significantly contribute to nonattainment in, or 
interfere with maintenance in, that particular area. EPA believes that 
this approach for identifying areas that are predicted to be 
nonattainment and significantly impacted by other states, or have 
difficulty maintaining the NAAQS, is appropriate to evaluate a state's 
submission in relation to the elements of CAA section 
110(a)(2)(D)(i)(I) pertaining to significant contribution to 
nonattainment and interference with maintenance.
    EPA continues to believe that the more widespread and serious 
transport problems in the eastern United States are analytically 
distinct.\14\ For the 2006 PM2.5 NAAQS, EPA believes that 
nonattainment and maintenance problems in the western United States are 
relatively local in nature with only limited impacts from interstate 
transport. In the Transport Rule, EPA did not calculate the portion of 
any downwind state's predicted PM2.5 concentrations that 
would result from emissions from individual western states, such as 
Arizona. Accordingly, EPA believes that section 110(a)(2)(D)(i)(I) SIP 
submissions for states outside the geographic area analyzed to develop 
the Transport Rule may be evaluated using a ``weight of the evidence'' 
approach that takes into account available relevant information, such 
as that recommended by EPA in the 2006 PM2.5 NAAQS 
Infrastructure Guidance. Such information may include, but is not 
limited to, the amount of emissions in the state relevant to the NAAQS 
in question, the meteorological conditions in the area, the distance 
from the state to the nearest monitors in other states that are 
appropriate receptors, or such other information as may be probative to 
consider whether sources in the state may contribute significantly to 
nonattainment or interfere with maintenance of the 2006 24-hour 
PM2.5 NAAQS in other states. These submissions can rely on 
modeling when acceptable modeling technical analyses are available, but 
EPA does not believe that modeling is necessarily required if other 
available information is sufficient to evaluate the presence or degree 
of interstate transport in a given situation.
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    \14\ See Transport Rule Proposal, 75 FR 45210 at 45227 (August 
2, 2010).
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II. The State's Submittal

    CAA sections 110(a) and 110(l) require that revisions to a SIP be 
adopted by the State after reasonable notice and public hearing. EPA 
has promulgated specific procedural requirements for SIP revisions in 
40 CFR part 51, subpart F. These requirements include publication of 
notices, by prominent advertisement in the relevant geographic area, of 
a public hearing on the proposed revisions, a public comment period of 
at least 30 days, and an opportunity for a public hearing.
    On October 14, 2009, the Arizona Department of Environmental 
Quality (ADEQ) submitted the ``Arizona State Implementation Plan 
Revision under Clean Air Act Section 110(a)(1) and (2); 2006 
PM2.5 NAAQS, 1997 PM2.5 NAAQS and 1997 8-hour 
Ozone NAAQS,'' to address the requirements of CAA section 
110(a)(2)(D)(i)(I) for the 2006 PM2.5 NAAQS, among other 
requirements (``2009 Infrastructure Analysis'').\15\ Within that 
submittal, Appendix B, ``Clean Air Act Section 110(a)(2)(D)(i)--
Interstate Transport Analysis for the 2006 PM2.5 National 
Ambient Air Quality Standards'' (referred to herein as 
``PM2.5 Transport Analysis'') addresses the CAA section 
110(a)(2)(D)(i)(I) interstate transport requirements that are the 
subject of this proposed rule.
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    \15\ ADEQ intended for this SIP submittal to also address all 
other requirements of CAA section 110(a), excepting section 
110(a)(2)(G), for the 1997 8-hour ozone and PM2.5 NAAQS 
and the 2006 PM2.5 NAAQS. See letter dated October 14, 
2009, from Eric C. Massey, Air Quality Director, ADEQ, to Laura 
Yoshii, Acting Regional Administrator, EPA Region 9, with 
enclosures. EPA has proposed to act on this submittal for purposes 
of addressing the other ``infrastructure'' requirements of CAA 
section 110(a) in a separate proposed rule published on June 27, 
2012 (77 FR 38239).
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    ADEQ's October 14, 2009 submittal includes public process 
documentation for the 2009 Infrastructure Analysis, including the 
PM2.5 Transport Analysis. In addition, the SIP revision 
includes documentation of a duly noticed public hearing held on 
September 16, 2009, on the proposed 2009 Infrastructure Analysis.
    We find that the process followed by ADEQ in adopting the 
PM2.5 Transport Analysis complies with the procedural 
requirements for SIP revisions under CAA section 110 and EPA's 
implementing regulations.

III. EPA's Evaluation

    To determine whether the CAA section 110(a)(2)(D)(i)(I) requirement 
is satisfied, EPA must determine whether a state's emissions contribute 
significantly to nonattainment or

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interfere with maintenance in downwind areas. If this factual finding 
is in the negative, then section 110(a)(2)(D)(i)(I) does not require 
any changes to a state's SIP. If, however, the evaluation reveals that 
emissions from sources within the state do contribute significantly to 
nonattainment or interfere with maintenance in other states, then the 
state must adopt substantive provisions to eliminate those emissions. 
The state could achieve any required reductions through traditional 
command and control programs, or at its own election, through 
participation in a cap and trade program. Consistent with EPA's 
approach in the 1998 NOX SIP call, the 2005 CAIR, and the 
2011 Transport Rule,\16\ EPA is evaluating these impacts with respect 
to specific monitors identified as having nonattainment and/or 
maintenance problems, which we refer to as ``receptors.'' EPA notes 
that no single piece of information is by itself dispositive of the 
issue. Instead, the total weight of all the evidence taken together is 
used to evaluate significant contributions to nonattainment or 
interference with maintenance of the 2006 24-hour PM2.5 
NAAQS in another state.
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    \16\ See NOX SIP Call, 63 FR 57371 (October 27, 
1998); CAIR, 70 FR 25172 (May 12, 2005); and Transport Rule or 
Cross-State Air Pollution Rule, 76 FR 48208 (August 8, 2011).
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    This proposed approval addresses the requirements of CAA section 
110(a)(2)(D)(i)(I) for the 2006 24-hour PM2.5 NAAQS in 
several ways. It takes into account Arizona's PM2.5 
Transport Analysis, which explains that meteorological and other 
characteristics in Arizona and in the surrounding areas reduce the 
likelihood that Arizona's emissions contribute significantly to 
nonattainment or interfere with maintenance of the 2006 24-hour 
PM2.5 NAAQS in any downwind state. In addition, EPA has 
supplemented its evaluation of Arizona's submittal with a review of the 
monitors in other states that are appropriate ``nonattainment 
receptors'' or ``maintenance receptors,'' consistent with EPA's 
approach in the Transport Rule, and additional technical information to 
consider whether sources in Arizona contribute significantly to 
nonattainment or interfere with maintenance of the 2006 24-hour 
PM2.5 NAAQS in other states.
    Our Technical Support Document (TSD) contains a more detailed 
evaluation and is available in the public docket for this rulemaking, 
which may be accessed online at http://www.regulations.gov, docket 
number EPA-R09-OAR-2012-0398. We provide below a summary of our 
analysis.

A. Evaluation of Significant Contribution to Nonattainment

    EPA reviewed the State of Arizona's PM2.5 Transport 
Analysis and additional technical information to evaluate the potential 
for Arizona emissions to contribute significantly to nonattainment of 
the 2006 PM2.5 NAAQS at specified monitoring sites in the 
western United States.\17\ EPA first identified as ``nonattainment 
receptors'' all monitoring sites in the western states that had 
recorded PM2.5 design values above the level of the 2006 24-
hour PM2.5 NAAQS (35 [mu]g/m\3\) during the years 2008-
2010.\18\ See Section III of the TSD for more a more detailed 
description of EPA's methodology for selection of nonattainment 
receptors. Because geographic distance is a relevant factor in the 
assessment of potential pollution transport, EPA focused its review on 
information related to potential transport of PM2.5 
pollution from Arizona to nonattainment receptors in the states 
bordering Arizona: Utah, Nevada, and California.\19\ With respect to 
Utah and Nevada, as detailed in the TSD, EPA believes that the 
following factors support a finding that emissions from Arizona do not 
significantly contribute to nonattainment of the 2006 24-hour 
PM2.5 NAAQS in either of these states: (1) Technical 
information indicating that elevated PM2.5 levels at 
nonattainment receptors are predominantly caused by local emission 
sources, (2) air quality data indicating that regional background 
levels of PM2.5 are generally low during the time periods of 
elevated PM2.5 at these receptors, and (3) the presence of 
significant terrain, which creates a physical impediment to pollution 
transport. Similarly and again as detailed in the TSD, with respect to 
California, technical information indicating that elevated 
PM2.5 levels at the nonattainment receptors are 
predominantly caused by local emission sources and that the dominant 
air flows across California are from the west to the east support a 
finding that emissions from the state of Arizona do not significantly 
contribute to nonattainment of the 2006 24-hour PM2.5 
standards in California.
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    \17\ EPA has also considered potential PM2.5 
transport from Arizona to the nearest nonattainment and maintenance 
receptors located in the eastern, midwestern and southern states 
covered by the Transport Rule and believes it is reasonable to 
conclude that, given the significant distance from Arizona to the 
nearest such receptor (in Illinois) and the relatively insignificant 
amount of emissions from Arizona that could potentially be 
transported such a distance, emissions from Arizona sources do not 
significantly contribute to nonattainment or interfere with 
maintenance of the 2006 24-hour PM2.5 NAAQS at this 
location. These same factors also support a finding that emissions 
from Arizona sources neither contribute significantly to 
nonattainment nor interfere with maintenance of the 2006 24-hour 
PM2.5 NAAQS at any location further east. See TSD at 
Section I.B.3.
    \18\ Because CAIR did not cover states in the western United 
States, these data are not significantly impacted by the remanded 
CAIR and thus could be considered in this analysis. In contrast, 
recent air quality data in the eastern, midwestern and southern 
states are significantly impacted by reductions associated with CAIR 
and because the Transport Rule was developed to replace CAIR, EPA 
could not consider reductions associated with the CAIR in the base 
case transport analysis for those states. See 76 FR at 48223-24.
    \19\ EPA did not identify any nonattainment receptors in New 
Mexico or Colorado.
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    EPA also evaluated potential PM2.5 transport to 
nonattainment receptors in the more distant western states of Oregon, 
Washington, Idaho, and Montana.\20\ EPA believes that the following 
factors support a finding that emissions from Arizona do not 
significantly contribute to nonattainment of the 2006 24-hour 
PM2.5 NAAQS in any of these states: (1) The significant 
distance from the State of Arizona to the nonattainment receptors in 
these states, (2) technical information indicating that elevated 
PM2.5 levels at nonattainment receptors in these states are 
predominantly caused by local emission sources, (3) air quality data 
indicating that regional background levels of PM2.5 are 
generally low during the time periods of elevated PM2.5 at 
these receptors, and (4) the presence of significant terrain, which 
creates a physical impediment to pollution transport.
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    \20\ EPA did not identify any nonattainment receptors in 
Wyoming.
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    Based on this evaluation of Arizona's PM2.5 Transport 
Analysis and additional technical information, EPA proposes to conclude 
that emissions of direct PM2.5 and PM2.5 
precursors from sources in the State of Arizona do not significantly 
contribute to nonattainment of the 2006 24-hour PM2.5 
standards in any other state and that CAA section 110(a)(2)(D)(i)(I) 
therefore does not require Arizona to adopt additional controls for 
purposes of implementing the 2006 24-hour PM2.5 standards.

B. Evaluation of Interference With Maintenance

    EPA reviewed the State of Arizona's PM2.5 Transport 
Analysis and additional technical information to evaluate the potential 
for Arizona emissions to interfere with maintenance of the 2006 24-hour 
PM2.5 standards at specified monitoring sites in the western 
U.S. EPA first identified as ``maintenance

[[Page 44555]]

receptors'' all monitoring sites in the western states that had 
recorded PM2.5 design values above the level of the 2006 24-
hour PM2.5 NAAQS (35 [mu]g/m\3\) during the 2006-2008 and/or 
2007-2009 periods but below this standard during the 2008-2010 period. 
See section IV of the TSD for more information regarding EPA's 
methodology for selection of maintenance receptors. All of the 
maintenance receptors in the western states are located in California, 
Utah, and Arizona. EPA therefore evaluated the potential for transport 
of Arizona emissions to the maintenance receptors located in California 
and Utah.\21\ As detailed in the TSD, EPA believes that the following 
factors support a finding that emissions from Arizona do not interfere 
with maintenance of the 2006 24-hour PM2.5 NAAQS in either 
state: (1) Technical information indicating that elevated 
PM2.5 levels at these maintenance receptors are 
predominantly caused by local emission sources, and (2) technical 
information indicating that the dominant air flows across California 
are from the west to the east.
---------------------------------------------------------------------------

    \21\ As this analysis focused on interstate transport, EPA did 
not evaluate the impact of Arizona emissions on maintenance 
receptors within Arizona. (EPA has not identified any nonattainment 
receptors in Arizona.)
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    Based on this evaluation of Arizona's PM2.5 Transport 
Analysis and additional technical information, EPA proposes to conclude 
that emissions of direct PM2.5 and PM2.5 
precursors from sources in the State of Arizona do not interfere with 
maintenance of the 2006 24-hour PM2.5 standards in any other 
state and that CAA section 110(a)(2)(D)(i)(I) therefore does not 
require Arizona to adopt additional controls for purposes of 
implementing the 2006 24-hour PM2.5 standards.

C. Section 110(l) of the Act

    Section 110(l) of the Act prohibits EPA from approving any SIP 
revision that would interfere with any applicable requirement 
concerning attainment and reasonable further progress (RFP) or any 
other applicable requirement of the Act. The PM2.5 Transport 
Analysis contains no regulatory provisions and does not affect any 
requirement in Arizona's applicable implementation plan. We propose to 
determine that our approval of the PM2.5 Transport Analysis 
would comply with CAA section 110(l) because the proposed SIP revision 
would not interfere with the on-going process for ensuring that 
requirements for RFP and attainment of the NAAQS are met. The SIP 
revision does not alter any provisions in the SIP as EPA has concluded, 
based on its supplemental analysis, that the existing SIP is sufficient 
to meet the requirements of 110(a)(2)(D)(i)(I). Our TSD contains a more 
detailed discussion of our evaluation.

IV. Proposed Action

    Under section 110(k) of the Clean Air Act, EPA is proposing to 
approve a SIP revision submitted by the State of Arizona on October 14, 
2009 and to determine, based on that submission and additional EPA 
analysis, that emissions from Arizona sources do not contribute 
significantly to nonattainment of the 2006 24-hour PM2.5 
NAAQS in any other state or interfere with maintenance of the 2006 24-
hour PM2.5 NAAQS by any other state. Accordingly, we propose 
to conclude that the existing SIP is adequate to address the 
requirements of section 110(a)(2)(D)(i)(I) of the Clean Air Act (CAA) 
for the 2006 National Ambient Air Quality Standard (NAAQS or standard) 
for fine particulate matter (PM2.5) and that additional 
control measures in Arizona are not necessary for this purpose.
    EPA is soliciting public comments on this proposal and will accept 
comments until the date noted in the DATES section above.

V. Statutory and Executive Order Reviews

    Under the Clean Air Act, the Administrator is required to approve a 
SIP submission that complies with the provisions of the Act and 
applicable Federal regulations. 42 U.S.C. 7410(k); 40 CFR 52.02(a). 
Thus, in reviewing SIP submissions, EPA's role is to approve state 
choices, provided that they meet the criteria of the Clean Air Act. 
Accordingly, this action merely proposes to approve state law as 
meeting Federal requirements and does not impose additional 
requirements beyond those imposed by state law. For that reason, this 
proposed action:
     Is not a ``significant regulatory action'' subject to 
review by the Office of Management and Budget under Executive Order 
12866 (58 FR 51735, October 4, 1993);
     Does not impose an information collection burden under the 
provisions of the Paperwork Reduction Act (44 U.S.C. 3501 et seq.);
     Is certified as not having a significant economic impact 
on a substantial number of small entities under the Regulatory 
Flexibility Act (5 U.S.C. 601 et seq.);
     Does not contain any unfunded mandate or significantly or 
uniquely affect small governments, as described in the Unfunded 
Mandates Reform Act of 1995 (Pub. L. 104-4);
     Does not have Federalism implications as specified in 
Executive Order 13132 (64 FR 43255, August 10, 1999);
     Is not an economically significant regulatory action based 
on health or safety risks subject to Executive Order 13045 (62 FR 
19885, April 23, 1997);
     Is not a significant regulatory action subject to 
Executive Order 13211 (66 FR 28355, May 22, 2001);
     Is not subject to requirements of Section 12(d) of the 
National Technology Transfer and Advancement Act of 1995 (15 U.S.C. 272 
note) because application of those requirements would be inconsistent 
with the Clean Air Act; and
     Does not provide EPA with the discretionary authority to 
address, as appropriate, disproportionate human health or environmental 
effects, using practicable and legally permissible methods, under 
Executive Order 12898 (59 FR 7629, February 16, 1994).

In addition, this proposed rule does not have tribal implications as 
specified by Executive Order 13175 (65 FR 67249, November 9, 2000), 
because the SIP is not approved to apply in Indian country located in 
the state, and EPA notes that it will not impose substantial direct 
costs on tribal governments or preempt tribal law.

List of Subjects in 40 CFR Part 52

    Environmental protection, Air pollution control, Intergovernmental 
relations, Nitrogen dioxide, Ozone, Reporting and recordkeeping 
requirements, Volatile organic compounds.

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

    Dated: July 20, 2012.
Jared Blumenfeld,
Regional Administrator, Region IX.
[FR Doc. 2012-18545 Filed 7-27-12; 8:45 am]
BILLING CODE 6560-50-P


