[Federal Register Volume 76, Number 67 (Thursday, April 7, 2011)]
[Proposed Rules]
[Pages 19292-19304]
[FR Doc No: 2011-8330]

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 52

[EPA-R10-OAR-2011-0003; FRL-9291-4]

Approval and Promulgation of Implementation Plans; Oregon;
Interstate Transport of Pollution; Significant Contribution to
Nonattainment and Interference With Maintenance Requirements

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.

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SUMMARY: EPA is proposing to approve a portion of the State
Implementation Plan (SIP) revision submitted by the State of Oregon for
the purpose of addressing the interstate transport provisions of Clean
Air Act (CAA) section 110(a)(2)(D)(i)(I) for the 1997 8-hour ozone
National Ambient Air

Quality Standards (NAAQS or standards) and the 1997 fine particulate
matter (PM2.5) NAAQS. Section 110(a)(2)(D)(i) of the CAA
requires that each State have adequate provisions to prohibit air
emissions from adversely affecting air quality in other States through
interstate transport. EPA is proposing to approve Oregon's SIP revision
for the 1997 8-hour ozone and 1997 PM2.5 NAAQS as meeting
the requirements of CAA section 110(a)(2)(D)(i)(I) to prohibit
emissions that will contribute significantly to nonattainment of the
these standards in any other State and to prohibit emissions that will
interfere with maintenance of these standards by any other State.

DATES: Written comments must be received on or before May 9, 2011.

ADDRESSES: Submit your comments, identified by Docket ID No. EPA-R10-
OAR-2011-0003, by one of the following methods:
    A. http://www.regulations.gov. Follow the on-line instructions for
submitting comments.
    B. E-Mail<EMAIL_ADDRESS>    C. Mail: Donna Deneen, U.S. Environmental Protection Agency, Region
10, 1200 Sixth Avenue, Suite 900, Mail Stop: AWT-107, Seattle, WA
98101.
    D. Hand Delivery: U.S. Environmental Protection Agency, Region 10,
Attn: Donna Deneen (AWT-107), 1200 Sixth Avenue, Suite 900, Seattle,
Washington 98101, 9th Floor. Such deliveries are only accepted during
normal hours of operation, and special arrangements should be made for
deliveries of boxed information.
    Instructions: Direct your comments to Docket ID No. EPA-R10-OAR-
2011-0003. EPA's policy is that all comments received 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 information claimed to be
Confidential Business Information (CBI) or other information whose
disclosure is restricted by statute. Do not submit information that you
consider to be CBI or otherwise protected through http://www.regulations.gov or e-mail. The http://www.regulations.gov Web site
is an ``anonymous access'' system, which means EPA will not know your
identity or contact information unless you provide it in the body of
your comment. If you send an e-mail comment directly to EPA without
going through http://www.regulations.gov, your e-mail address will be
automatically captured and included as part of the comment that is
placed in the public docket and made available on the Internet. If you
submit an electronic comment, EPA recommends that you include your name
and other contact information in the body of you comment and with any
disk or CD-ROM you submit. 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. Electronic files should avoid
the use of special characters, any form of encryption, and be free of
any defects or viruses.
    Docket: All documents in the electronic docket are listed in the
www.regulations.gov index. Although listed in the index, some
information, i.e., CBI or other information whose disclosure is
restricted by statute, is not publicly available. Certain other
material, such as copyrighted material, is not placed on the Internet
and will be publicly available only in hard copy form. Publicly
available docket materials are available either electronically in
http://www.regulations.gov or in hard copy during normal business hours
at the Office of Air, Waste and Toxics, U.S. Environmental Protection
Agency, Region 10, 1200 Sixth Avenue, Suite 900, Seattle, Washington
98101.

FOR FURTHER INFORMATION CONTACT: Donna Deneen,<PHONE_NUMBER> or
<EMAIL_ADDRESS>
SUPPLEMENTARY INFORMATION: Throughout this notice, the words ``we'',
``us'', or ``our'' means the Environmental Protection Agency (EPA).

Table of Contents

I. What proposed action is EPA taking?
II. What is a SIP?
III. What is the background for this proposed action?
IV. What is the state process to submit these materials to EPA?
V. What is EPA's evaluation of the state's submission?
    A. EPA's Evaluation of Significant Contribution to Nonattainment
    1. Significant Contribution to Nonattainment Evaluation for the
1997 8-Hour Ozone NAAQS
    2. Significant Contribution to Nonattainment Evaluation for the
1997 PM2.5 NAAQS
    3. Conclusion Regarding Significant Contribution to
Nonattainment
    B. EPA's Evaluation of Interference With Maintenance
    1. Oregon's 2010 Interstate Transport SIP
    2. Interference With Maintenance Evaluation for the 8-Hour Ozone
NAAQS
    3. Interference With Maintenance Evaluation for the 1997
PM2.5 NAAQS
    4. Conclusion Regarding Interference With Maintenance
VI. Proposed Action
VII. Statutory and Executive Order Reviews

I. What proposed action is EPA taking?

    EPA is proposing to approve a portion of Oregon's Interstate
Transport State Implementation Plan (SIP) revision for the 1997 8-hour
ozone and 1997 PM2.5 NAAQS submitted by the Oregon
Department of Environmental Quality (ODEQ) on June 23, 2010.\1\
Specifically, we are proposing to approve the portion of the interstate
transport SIP revision that addresses the following elements of CAA
section 110(a)(2)(D)(i): (1) Significant contribution to nonattainment
of these NAAQS in any other state; and (2) interference with
maintenance of these NAAQS by any other state. EPA will address element
(3), interference with any other state's required measures to prevent
significant deterioration (PSD) of its air quality; and element (4),
interference with any other state's required measures to protect
visibility, in a separate action.\2\ This proposed action does not
address the requirements of the 2006 PM2.5 NAAQS or the 2008
8-hour ozone NAAQS; those standards will be addressed in future
actions.
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    \1\ See transmittal letters dated June 23, 2010, from Joni
Hammond, Deputy Director, ODEQ, and December 23, 2010, from Dick
Pedersen, Director, ODEQ, to Dennis McLerran, Regional
Administrator, EPA Region 10.
    \2\ On March 8, 2011, EPA proposed to approve the Oregon
interstate transport SIP provisions addressing interference with any
other state's required measures to protect visibility. See 76 FR
12651 (March 8, 2011).
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II. What is a SIP?

    Section 110(a) of the CAA requires each state to develop a plan
that provides for the implementation, maintenance, and enforcement of
the NAAQS. EPA establishes NAAQS under section 109 of the CAA.
Currently, the NAAQS address six criteria pollutants: Carbon monoxide,
nitrogen dioxide, ozone, lead, particulate matter, and sulfur dioxide.
    The plan developed by a state is referred to as the SIP. The
content of the SIP is specified in section 110 of the CAA, other
provisions of the CAA, and applicable regulations. SIPs can be
extensive, containing state regulations or other enforceable measures
and various types of supporting information, such as emissions
inventories, monitoring networks, and modeling demonstrations.
    A primary purpose of the SIP is to provide the air pollution
regulations, control strategies, and other means or techniques
developed by the state to

ensure that the ambient air within that state meets the NAAQS. However,
another important aspect of the SIP is to ensure that emissions from
within the state do not have certain prohibited impacts upon the
ambient air in other states through interstate transport of pollutants.
This SIP requirement is specified in section 110(a)(2)(D). Pursuant to
that provision, each state's SIP must contain provisions adequate to
prevent emissions that significantly contribute to violations of the
NAAQS in any other state, interfere with maintenance in any other
state, interfere with any other state's required measures to prevent
significant deterioration of its air quality, and interfere with any
other state's required measures to protect visibility.
    States are required to update or revise SIPs under certain
circumstances. One such circumstance is EPA's promulgation of a new or
revised NAAQS. Each state must submit these revisions to EPA for
approval and incorporation into the federally-enforceable SIP.

III. What is the background for this proposed action?

    On July 18, 1997, EPA promulgated new standards for 8-hour ozone
\3\ and fine particulate matter \4\ (PM2.5). This proposed
action is in response to the promulgation of these standards (the 1997
8-hour ozone NAAQS and 1997 PM2.5 NAAQS).
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    \3\ See 62 FR 38856. The level of the 1997 8-hour ozone NAAQS is
0.08 parts per million (ppm). 40 CFR part 50.10. The 8-hour ozone
standard is met when the 3-year average of the annual 4th highest
daily maximum 8-hour ozone concentrations is 0.08 ppm or less (i.e.,
less than 0.085 ppm based on the rounding convention in 40 CFR part
50 Appendix I). This 3-year average is referred to as the ``design
value.''
    \4\ See 62 FR 38652. The level of the 1997 PM2.5
NAAQS are 15.0 [micro]g/m\3\ (annual arithmetic mean concentration)
and 65 [micro]g/m\3\ (24-hour average concentration). 40 CFR part
50.7. The annual standard is met when the 3-year average of the
annual mean concentrations is 15.0 [micro]g/m\3\ or less (i.e., less
than 15.05 [micro]g/m\3\ based on the rounding convention in 40 CFR
part 50 Appendix N Section 4.3). The 24-hour standard is met when
the 3-year average annual 98th percentile of 24-hour concentrations
is 65 [micro]g/m\3\ or less (i.e., less than 65.5 [micro]g/m\3\
based on the rounding convention in 40 CFR part 40 Appendix N
Section 4.3). Id. These 3-year averages are referred to as the
annual PM2.5 and 24-hour PM2.5 ``design
values,'' respectively.
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    Section 110(a)(1) of the CAA requires states to submit SIPs to
address a new or revised NAAQS within three years after promulgation of
such standards, or within such shorter period as EPA may prescribe.
Section 110(a)(2) lists the elements that such new SIPs must address,
as applicable, including section 110(a)(2)(D)(i) which pertains to
interstate transport of certain emissions. On August 15, 2006, EPA
issued a guidance memorandum that provides recommendations to states
for making submissions to meet the requirements of section
110(a)(2)(D)(i) for the 1997 8-hour ozone and 1997 PM2.5
standards (2006 Guidance).\5\
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    \5\ Memorandum from William T. Harnett entitled ``Guidance for
State Implementation Plan (SIP) Submissions 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.
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    The interstate 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 rulemaking EPA is
addressing the first two elements of this subsection.
    The first element of section 110(a)(2)(D)(i)(I) requires that a
state's SIP for a new or revised NAAQS must contain adequate measures
to prohibit emissions from sources within the state that ``contribute
significantly'' to nonattainment of the NAAQS in another state. The
second element of CAA section 110(a)(2)(D)(i)(I) requires that a
state's SIP must 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.
    The CAA does not specifically mandate how to determine significant
contribution to nonattainment or interference with maintenance.
Therefore, EPA has interpreted these terms in past regulatory actions,
such as the 1998 NOX SIP Call, in which 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\ The
NOX SIP Call was the mechanism through which EPA evaluated
whether or not the NOX emissions from sources in certain
states had such 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.
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    \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 (DC 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 (DC Cir.
2008).
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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 the 2005 Clean Air Interstate Rule (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.\7\ 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 determined would either be in
violation of the NAAQS, or would be in jeopardy of violating the NAAQS,
in a modeled future year unless action 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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    \7\ 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;
Final Rule,'' at 70 FR 25162 at 25263-69 (May 12, 2005).
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    EPA's 2006 Guidance addressed CAA section 110(a)(2)(D)(i)
requirements for the 1997 8-hour ozone NAAQS and 1997 PM2.5
NAAQS. For those states subject to CAIR, EPA indicated that compliance
with CAIR would meet the two requirements of section 110(a)(2)(D)(i)(I)
for these NAAQS. For states outside of the CAIR region, the 2006
Guidance recommended various methods by which states might evaluate
whether or not their emissions significantly contribute to
nonattainment of the 1997 8-hour ozone or the 1997 PM2.5
NAAQS in another state. Among other methods, EPA recommended
consideration of available EPA modeling conducted in conjunction with
the CAIR, or in the absence of such EPA modeling, consideration of
other information such as the amount of emissions, the geographic
location of violating areas, meteorological data, or various other
forms of information that would be relevant to assessing the likelihood
of significant contribution to violations of the NAAQS in another
state.
    The assessment of significant contribution to nonattainment is not
restricted to impacts upon areas that are formally designated
nonattainment. Consistent with EPA's approach in CAIR and recently in
the Transport Rule

Proposal, as discussed further below, this impact must be evaluated
with respect to monitors showing a violation of the NAAQS.\8\
Furthermore, although relevant information other than modeling may be
considered in assessing the likelihood of significant contribution to
nonattainment of the 8-hour ozone or PM2.5 NAAQS in another
state, 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
violations of the 1997 8-hour ozone or 1997 PM2.5 NAAQS in
another state.
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    \8\ See 63 FR 57371 (October 27, 1998), NOX SIP Call;
70 FR 25172 (May 12, 2005), CAIR; and 75 FR 45210 (August 2, 2010),
Transport Rule Proposal.
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    As to the second element of section 110(a)(2)(D)(i), for states not
within the CAIR region, EPA recommended that states evaluate whether or
not emissions from their sources would ``interfere with maintenance''
in other states following the conceptual approach adopted by EPA in
CAIR. After recommending various types of information that could be
relevant for the technical analysis to support the SIP submission, such
as the amount of emissions and meteorological conditions in the state,
EPA further indicated that it would be appropriate for the state to
assess impacts of its emissions on other states using considerations
comparable to those used by EPA ``in evaluating significant
contribution to nonattainment in the CAIR.'' \9\ EPA did not make
specific recommendations for how states should assess interference with
maintenance separately, and discussed the first two elements of section
110(a)(2)(D)(i) together without explicitly differentiating between
them.
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    \9\ 2006 Guidance at 5.
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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.\10\ 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.'' \11\ EPA's approach, the court reasoned, would leave
areas that are ``barely meeting attainment'' with ``no recourse'' to
address upwind emissions sources.\12\ 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. In addition to affecting CAIR directly, the court's
decision in the North Carolina case indirectly affects EPA's
recommendations to states in the 2006 Guidance with respect to the
interfere with maintenance element of section 110(a)(2)(D)(i) because
the agency's guidance suggested that states use an approach comparable
to that used by EPA in CAIR.
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    \10\ See North Carolina v. EPA, 531 F.3d 896 (DC Circuit 2008).
    \11\ 531 F.3d at 909.
    \12\ Ibid.
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    To address the judicial remand of CAIR, EPA has recently proposed a
new rule to address interstate transport of air pollution pursuant to
section 110(a)(2)(D)(i), the ``Federal Implementation Plans to Reduce
Interstate Transport of Fine Particulate Matter and Ozone'' (Transport
Rule Proposal).\13\ As part of the Transport Rule Proposal, EPA
specifically reexamined the section 110(a)(2)(D)(i)(I) requirements
that emissions from sources in a state must not ``contribute
significantly to nonattainment'' or ``interfere with maintenance'' of
the 1997 8-hour ozone NAAQS and 1997 PM2.5 NAAQS in other
states. In the proposal, EPA developed an approach to identify areas
that it predicts to be violating the 1997 8-hour ozone and
PM2.5 NAAQS in the future, and areas that it predicts to be
close to the level of these NAAQS in the future 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.
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    \13\ See 75 FR 45210 (August 2, 2010).
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    As described in more detail below, EPA evaluated data from existing
monitors over three overlapping 3-year periods (i.e., 2003-2005, 2004-
2006, and 2005-2007), as well as air quality modeling data, in order to
determine which areas are predicted to be violating the 1997 8-hour
ozone and PM2.5 NAAQS in 2012, and which areas are predicted
potentially to have difficulty maintaining attainment as of that date.
In essence, if an area's projected data for 2012 indicates that it
would be violating the NAAQS based on the average of these three
overlapping periods, then this monitor location is appropriate for
comparison for purposes of the significant contribution to
nonattainment element of section 110(a)(2)(D)(i). If, however, an
area's projected data indicate that it would be violating the NAAQS
based on the highest single period, but not over the average of the
three periods, then this monitor location is appropriate for comparison
for purposes of the interfere with maintenance element of the
statute.\14\
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    \14\ A memorandum in the docket for this action provides the
information EPA used to identify monitors that are receptors for
evaluation of significant contribution or interference with
maintenance for certain states in the western United States. See
Memorandum from Brian Timin, EPA Office of Air Quality Planning and
Standards, ``Documentation of Future Year Ozone and Annual
PM2.5 Design Values for Monitors in Western States,''
August 23, 2010 (Timin Memo).
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    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 or to 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.\15\
EPA's 2006 Guidance did not provide this specific recommendation to
states, but in light of the court's decision on CAIR, EPA will itself
follow this approach in evaluating the Oregon submission.
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    \15\ To begin this analysis, EPA first identifies all monitors
projected to be in nonattainment or, based on historic variability
in air quality, projected to have maintenance problems in 2012.
Monitors projected to be in nonattainment are those with future year
design values that violate the standard, based on the projection of
5-year weighted average concentrations. Monitors projected to have
maintenance problems are those at risk of not staying in attainment
because the air quality data is close enough to the level of the
1997 8-hour ozone and PM2.5 NAAQS that minor variations
in weather or emissions could result in violations of the NAAQS in
2012.
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    As explained in the 2006 Guidance, EPA does not believe that
section 110(a)(2)(D)(i) SIP submissions from all states necessarily
need to follow precisely the same analytical approach of CAIR. In the
2006 Guidance, EPA stated that: ``EPA believes that the contents of the
SIP submission required by section 110(a)(2)(D) may vary, depending
upon the facts and circumstances related to the specific NAAQS. In
particular, the data and analytical tools available at the time the
State develops and submits a SIP for a new or revised NAAQS necessarily

affects the contents of the required submission.'' \16\ EPA also
indicated in the 2006 Guidance that it did not anticipate that sources
in states outside the geographic area covered by CAIR were
significantly contributing to nonattainment, or interfering with
maintenance, in other states.\17\ As noted in the Transport Rule
Proposal, EPA continues to believe that the more widespread and serious
transport problems in the eastern United States are analytically
distinct.\18\ For the 1997 8-hour ozone and 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 Proposal, EPA did not
calculate the portion of predicted ozone or PM concentrations in any
downwind state that would result from emissions from individual western
states, such as Oregon.
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    \16\ 2006 Guidance at 4.
    \17\ Ibid. at 5.
    \18\ See Transport Rule Proposal, 75 FR 45210 at 45227 (August
2, 2010).
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    Accordingly, EPA believes that section 110(a)(2)(D)(i) SIP
submissions for states outside the geographic area of the Transport
Rule Proposal may be evaluated using a ``weight of the evidence''
approach that takes into account the available relevant information,
such as that recommended by EPA in the 2006 Guidance for states outside
the area affected by CAIR. 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 significantly contribute to
nonattainment or interfere with maintenance of the 1997 8-hour ozone
and 1997 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.

II. What is the state process to submit these materials to EPA?

    CAA sections 110(a)(1) and (2) and section 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 June 23, 2010, and December 23, 2010, the Oregon Department of
Environmental Quality (ODEQ) submitted a SIP revision to update
Oregon's infrastructure SIP for ozone and PM2.5. Included in
this submittal was a SIP revision entitled ``Oregon SIP Infrastructure
for Addressing the Interstate Transport of Ozone and Fine Particulate
Matter'' to address the interstate transport SIP requirements of CAA
section 110(a)(2)(D)(i) for the 1997 8-hour ozone and 1997
PM2.5 NAAQS (2010 interstate transport SIP).\19\ ODEQ's June
23, 2010, submittal includes public process documentation for the 2010
interstate transport SIP submittal. In addition, the SIP revision
includes documentation of a duly noticed public hearing held on
December 22, 2009.
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    \19\ Oregon's submission addresses the interstate transport
requirements of the 1997 PM2.5 NAAQS, the 1997 8-hour
ozone NAAQS, the 2006 PM2.5 NAAQS, and the 2008 8-hour
ozone NAAQS. In this action, EPA is only taking action with respect
to CAA section 110(a)(2)(D)(i)(I) for the 1997 PM2.5 and
1997 8-hour ozone NAAQS.
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    We find that the process followed by ODEQ in adopting the 2010
interstate transport SIP complies with the procedural requirements for
SIP revisions under CAA section 110 and EPA's implementing regulations.

V. What is EPA's evaluation of the state's submission?

A. EPA's Evaluation of Significant Contribution to Nonattainment

    This proposed approval evaluates the significant contribution to
nonattainment element of section 110(a)(2)(D)(i)(I) for the 1997 8-hour
ozone and 1997 PM2.5 NAAQS in several ways. It takes into
account Oregon's 2010 interstate transport SIP, in which the State
explains that based on meteorological and other characteristics in
Oregon and in the surrounding areas, PM2.5 and ozone
precursor emissions from Oregon sources do not significantly contribute
to violations of the PM2.5 or ozone NAAQS in other
states.\20\ In addition, EPA has supplemented the State's analysis with
its own evaluation of the evidence, including a review of the nearest
monitors in other states that are appropriate nonattainment receptors,
in order to assess whether emissions sources in Oregon contribute
significantly to nonattainment of the 1997 8-hour ozone and
PM2.5 NAAQS in other states.
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    \20\ Oregon's submission makes this conclusion with respect to
not only the 1997 PM 2.5 NAAQS and 1997 8-hour ozone NAAQS, but also
the 2006 PM 2.5 NAAQS and the 2008 8-hour ozone NAAQS.
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    Finally, EPA has also reviewed recent ozone and PM2.5
monitoring data for the states bordering Oregon to consider whether
Oregon emissions could significantly contribute to violations of the
1997 8-hour ozone or PM2.5 NAAQS in those states.
1. Significant Contribution to Nonattainment Evaluation for the 1997 8-
Hour Ozone NAAQS
    To address whether emissions from Oregon sources significantly
contribute to nonattainment of the 8-hour ozone NAAQS in another state,
the State argued in the 2010 interstate transport SIP that
meteorological and other characteristics of the Pacific Northwest
support a finding that emissions from Oregon sources do not
significantly contribute to violations of the PM2.5 or ozone
NAAQS in other states. Oregon pointed out that, in the Pacific
Northwest, exceedances of the 8-hour ozone standard occur in the summer
months, and during that season the prevailing winds \21\ are
predominantly from the north to northwest and, consequently, preclude
any significant influence from Oregon on Washington ozone nonattainment
areas.\22\ While acknowledging the possibility that prevailing summer
winds could result in some interstate transport of ozone forming
emissions to western Idaho, Nevada and northern California, the State
asserted in the 2010 interstate transport SIP that significant
distances and topography (such as major mountain ranges that separate
Oregon from California, Idaho and Nevada) would likely minimize the
significance of these impacts on other states. Oregon gave as an
example the largest major urban center in Oregon (the greater Portland
area), which it estimated is 400 to 700 miles away from urban areas in
western Idaho, Nevada, and northern California, and is separated by at
least one major mountain range (the Cascades).
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    \21\ This north/northwest prevailing wind direction was derived
from surface level winds and airport data and is not necessarily
indicative of the prevailing wind direction of typical weather
systems in the west.
    \22\ Note that there are currently no ozone nonattainment areas
in Oregon or Washington.
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    Oregon also pointed to its section 110 infrastructure SIP to show
that ODEQ

has the ability to participate as needed in future studies on regional
air pollution issues, or collaborate with other states if air quality
concerns are identified that require a case-specific evaluation of
interstate transport, and also ensures the legal mechanism for ODEQ to
take action as needed to reduce emissions to help attain compliance
with Federal NAAQS.
    Finally, the State explained that it consulted with air agencies in
Washington, Idaho, Nevada, and California and other agencies to
evaluate case-specific air quality problems that may involve regional
transport of air pollution. These staff-level communications indicated
no impacts on ozone concentrations in other states caused by transport
from the State of Oregon. The State added that if any future violations
of ozone standards occur, Oregon would work with other air agencies and
EPA as necessary to evaluate the role of interstate air pollution
transport. This consultation provided additional support for the
state's view that emissions from Oregon sources do not significantly
contribute to violations of the 1997 8-hour ozone NAAQS in other
states.
    Based on the information provided in its 2010 interstate transport
SIP, ODEQ concluded that emissions from air pollution sources in Oregon
do not significantly contribute to nonattainment of the 1997 8-hour
ozone NAAQS in other states.
    EPA does not necessarily agree that Oregon's methodology is
adequate for purposes of a section 110(a)(2)(D)(i) analysis. Therefore,
EPA is supplementing the State's submission with additional, and more
recent, information in order to assess this issue more fully. As noted
above, EPA is evaluating the State's 2010 interstate transport SIP
taking into account methodologies and analyses for the identification
of receptor monitors that was developed in the Transport Rule Proposal,
as well as EPA's projections of future air quality at monitors in
western states in the Timin Memo, and preliminary air quality data from
monitors in the states bordering Oregon. Although each of the factors
considered in the following analysis are not in and of themselves
determinative, consideration of these factors together provides a
reliable qualitative conclusion that emissions from Oregon do not
contribute significantly to nonattainment of the 1997 8-hour ozone
NAAQS at monitors in other states.
    The Transport Rule Proposal includes an approach to determining
whether emissions from a state contribute significantly to
nonattainment of the 1997 8-hour ozone NAAQS in other states.
Specifically, EPA used existing monitoring data to project future
concentrations of ozone at monitors to identify areas that are expected
to be violating the 1997 8-hour ozone NAAQS in 2012, based on the 5-
year weighted average design value. We call these monitors
``nonattainment receptors.'' To identify the states with emissions that
may contribute significantly to ozone nonattainment in other states,
the Transport Rule Proposal models the states' contributions to ambient
ozone levels at these nonattainment receptors.\23\ Because the
Transport Rule Proposal does not model the contribution of emissions
from Oregon (nor other western states not fully inside the Transport
Rule Proposal's modeling domain) to 8-hour ozone nonattainment
receptors in other states, our assessment in this proposed action
relies on a weight of evidence approach that considers relevant
information from the Transport Rule Proposal pertaining to states
within its modeling domain, and additional material such as
geographical and meteorological factors, EPA's projections of future
air quality at monitors in western states in the Timin Memo, and AQS
monitoring data.
---------------------------------------------------------------------------

    \23\ Transport Rule Proposal, 75 FR 45210 at 45253-45273.
---------------------------------------------------------------------------

    Our analysis begins by assessing Oregon's contribution to the
closest nonattainment receptors for the 1997 8-hour ozone standard. The
Transport Rule Proposal identifies within its modeling domain
(consisting of 37 states east of the Rocky Mountains, and the District
of Columbia) 11 nonattainment receptors for the 1997 8-hour ozone
standard. Of these, the nonattainment receptors closest to Oregon are
seven receptors in the Dallas-Fort Worth and Houston-Galveston-Brazoria
8-hour ozone nonattainment areas in eastern Texas. The remaining four
nonattainment receptors for the 1997 8-hour ozone NAAQS are in
Louisiana, New York, and Pennsylvania.\24\
---------------------------------------------------------------------------

    \24\ See Transport Rule Proposal, Table IV.C-11, 75 FR 45210 at
45252.
---------------------------------------------------------------------------

    The nonattainment receptors in Dallas-Fort Worth and Houston areas
are over 1200 miles from the closest point on Oregon's border, and the
receptors in Louisiana, New York, and Pennsylvania are significantly
further away. Although distance alone is not determinative in the
analysis of potential ozone transport, with increasing distance there
are greater opportunities for ozone and NOX dispersion and/
or removal from the atmosphere due to the effect of winds or chemical
sink processes. Moreover, the intervening Rocky Mountains act as a
natural barrier to air pollution transport. These factors together
support a conclusion that Oregon sources do not contribute
significantly to nonattainment of the 1997 8-hour ozone NAAQS in the
nearest areas with nonattainment receptors identified in the Transport
Rule Proposal.
    To assist in the evaluation of the potential for ozone transport
among western states, EPA also developed an additional analysis in the
Timin Memo identifying monitors projected to record violations of the
1997 8-hour ozone NAAQS in the western U.S. The Timin Memo identified
predicted future nonattainment receptors for the 1997 8-hour ozone
NAAQS in southern and central California. This analysis did not,
however, identify any projected nonattainment receptors for the 1997 8-
hour ozone NAAQS in any other western state.\25\ The nonattainment
receptor nearest to Oregon for the 1997 8-hour ozone NAAQS was
identified as Nevada County, California. Nevada County is approximately
170 miles south/southeast of the closest point on Oregon's border and
on the other side of intervening mountain ranges that act as a natural
barrier to air pollution transport. Although not determinative by
themselves, distance and topography are not favorable to 8-hour ozone
transport from Oregon to central California. In addition, prevailing
winds in the west generally move from south-westerly, westerly, or
north-westerly directions, as indicated by the typical movement of
weather systems. Hence central and southern California are not in the
predominant direction of winds from Oregon. Given the distance between
Oregon's border and central and southern California nonattainment
receptors, the intervening mountainous topography, and the general
direction of transport winds in the Western U.S., it is reasonable to
conclude that Oregon sources do not contribute significantly to
nonattainment of the 1997 8-hour ozone NAAQS in Nevada County or to any
more distant nonattainment receptors in California. EPA's analysis for
western states therefore supports our proposal to conclude that Oregon
sources do not contribute significantly to nonattainment of the 1997 8-
hour ozone NAAQS in any other state.
---------------------------------------------------------------------------

    \25\ See Timin Memo at Appendix B (``Base year 2003-2007 and
Future Year 2012 8-Hour Average Ozone Design Values--Western
States'').
---------------------------------------------------------------------------

    In addition to the information in the 2010 interstate transport SIP
and EPA's projections of future air quality in the Transport Rule
Proposal and in the

Timin Memo, EPA also evaluated preliminary air quality monitoring data
for the areas in states bordering Oregon that are designated
nonattainment for the 1997 8-hour ozone NAAQS. While significant
contribution must be measured not just against designated nonattainment
areas but also against areas with monitors showing violations of the
NAAQS, nonattainment areas are a convenient point of analysis. Two
states bordering Oregon--California and Nevada--have areas currently
designated nonattainment for the 1997 8-hour ozone standard. In
California, the closest nonattainment area is Butte County, and in
Nevada, the closest nonattainment area is the Las Vegas area in Clark
County. EPA designated both of these areas as nonattainment for the
1997 8-hour ozone standard in 2004. See 69 FR 23858 (April 30, 2004);
40 CFR 81.305 and 81.329. Both of these areas, however, have current
design values indicating attainment of the 1997 8-hour ozone NAAQS. Our
review of preliminary monitoring data for the 2007-2009 period
available in EPA's Air Quality System (AQS) database indicates that the
8-hour ozone design values for Butte County and Las Vegas during this
period were 82 and 74 ppb, respectively.\26\ We therefore believe it is
reasonable to conclude that Oregon sources are not contributing
significantly to nonattainment of the 1997 8-hour ozone NAAQS in Butte
County, California or Clark County, Nevada. The closest nonattainment
area to the Oregon border that had a design value above the 1997 8-hour
ozone NAAQS for the 2007-2009 period was Nevada County, California. As
noted above, given the distance between the Oregon border and Nevada
County, the intervening mountainous topography, and the general
direction of transport winds in the Western U.S., it is reasonable to
conclude that Oregon sources do not contribute significantly to
nonattainment in Nevada County or to any more distant central or
southern California 1997 8-hour ozone nonattainment areas. There are no
designated nonattainment areas in Idaho and Washington for the 1997 8-
hour ozone NAAQS. This is further support that Oregon sources do not
contribute significantly to nonattainment of the 1997 8-hour ozone
NAAQS in any other state.
---------------------------------------------------------------------------

    \26\ See EPA AQS, ``Preliminary Design Value Report,'' 2007-
2009, for Washington, Idaho, Nevada, and California.
---------------------------------------------------------------------------

    We also evaluated ozone monitoring data from the 2007-2009 period
from each of the ozone monitoring sites in Washington, Idaho, Nevada
and California, to determine whether the ozone levels in any of these
states violate the 1997 8-hour ozone NAAQS.\27\ We have identified no
design values above the 1997 8-hour ozone NAAQS at any of the monitors
in Washington, Idaho, or Nevada, nor any indication that emissions from
Oregon sources contribute significantly to nonattainment of the 1997 8-
hour ozone NAAQS in these adjacent states. Although AQS data for
California show 8-hour ozone design values above the 1997 NAAQS during
the 2007-2009 period, the closest monitor to Oregon that has a 2007-
2009 8-hour ozone design value above the 1997 NAAQS is located in
Nevada County. As noted above, given the distance between the Oregon
border and Nevada County, the intervening mountainous topography, and
the general direction of transport winds in the Western U.S., it is
reasonable to conclude that Oregon sources do not contribute
significantly to nonattainment in Nevada County or to any more distant
central or southern California monitors. This is further support that
Oregon sources do not contribute significantly to nonattainment of the
1997 8-hour ozone NAAQS in any other state.
---------------------------------------------------------------------------

    \27\ Id.
---------------------------------------------------------------------------

    Finally, none of the ozone monitors in Oregon have themselves
indicated a violation of the 1997 8-hour ozone NAAQS. The absence of
violations in Oregon itself does not rule out the possibility of
transport, but taken in conjunction with other relevant information,
including the distance from Oregon to areas with design values above
the 1997 8-hour ozone NAAQS and Pacific Northwest meteorology and
topography, this fact helps to support the conclusion that there is no
transport from Oregon resulting in significant contribution to
nonattainment in another state. Distance per se is also not an obstacle
to long range transport of ozone and its precursors, as discussed
above. However, with increasing distance there are greater
opportunities for ozone and NOX dispersion and removal from
the atmosphere due to the effects of winds and chemical sink processes.
In this context, the distance between Oregon sources and areas not
meeting the 8-hour ozone standard reduces, but does not exclude, the
possibility of significant contribution to nonattainment. Nevertheless,
the absence of violations in Oregon combined with the total weight of
all of the factors discussed above supports a conclusion that emissions
from its sources do not significantly contribute to nonattainment in
other states, in accordance with section 110(a)(2)(D)(i).
2. Significant Contribution to Nonattainment Evaluation for the 1997
PM2.5 NAAQS
    To address whether emissions from sources in Oregon significantly
contribute to nonattainment of the 1997 PM2.5 NAAQS in
another state, the State argued in its 2010 interstate transport SIP
that meteorological and other characteristics of any areas designated
nonattainment for the 1997 PM2.5 NAAQS in the surrounding
states of Washington, Idaho, Nevada, and California support a finding
that emissions from Oregon sources do not significantly contribute to
violations of the PM2.5 NAAQS or ozone NAAQS in other
states. Oregon explained that the closest nonattainment areas in
neighboring states are the Tacoma area (Pierce County) in Washington;
the Chico area (portions of Butte County) in California, and the Cache
Valley area in Southeast Idaho (portions of Cache County, Utah and
Franklin County, Idaho).\28\ Oregon argues that the area of highest
Oregon emission densities (Portland Metro area) is separated from these
PM2.5 nonattainment areas by significant distances and major
mountain ranges up to approximately 7000 feet. Oregon identifies one
exception--the Portland-Vancouver metro area, which shares a common air
shed between Oregon and Washington. Oregon, however, notes that both
Portland and Vancouver are in attainment with the PM2.5
NAAQS.
---------------------------------------------------------------------------

    \28\ Although the 2010 Interstate transport SIP identified these
areas as PM2.5 nonattainment areas, they are all 2006 24-
hour PM2.5 nonattainment areas. There are no 1997
PM2.5 nonattainment areas in Washington or Idaho, and the
closest 1997 PM2.5 nonattainment area to Oregon is in
California (San Joaquin County). Oregon asserts that its evaluation
of more stringent 2006 24-hour PM2.5 NAAQS nonattainment
areas is indicative of potential contribution to nonattainment of
the less stringent 1997 PM2.5 NAAQS.
---------------------------------------------------------------------------

    Oregon described typical seasonal wind patterns during the winter
when PM2.5 levels are the highest. It noted that wind speeds
are typically variable with the majority of wind speeds occurring at
less than 8 miles per hour, and a significant portion of low winds at
less than 5 miles per hour. Oregon explained that these low wind speeds
and air stagnation conditions do not lend themselves to long distance
air pollution transport, and noted that the Portland area can
experience high wind speeds in the winter travelling through the
Columbia River Gorge east of Portland that are not conducive to the
buildup of air pollution. Oregon concluded that general meteorology

supports the conclusion that high winter time PM2.5 levels
in Pacific Northwest communities are typically dominated by local
emission sources.
    Oregon also pointed to its section 110 infrastructure SIP to show
that ODEQ has the ability to participate as needed in future studies on
regional air pollution issues, or collaborate with other states if air
quality concerns are identified that require a case-specific evaluation
of interstate transport, and also ensures the legal mechanism for ODEQ
to take action as needed to reduce emissions to help attain compliance
with Federal NAAQS. Oregon stated that that high PM2.5
levels that threaten the NAAQS are investigated as needed to identify
contributing sources, including any potential role of interstate
transport.
    Finally, the state explained that it had consulted with air
agencies in Washington, Idaho, Nevada, and California and other
agencies to evaluate case-specific air quality problems that may
involve regional transport of air pollution. These staff-level
communications indicated no impacts on PM2.5 concentrations
in other states caused by transport from the state of Oregon, providing
additional support for the state's view that emissions from Oregon
sources do not significantly contribute to violations of the 1997
PM2.5 NAAQS in other states.
    Based on this and other information provided in its 2010 interstate
transport SIP, ODEQ concluded that emissions from air pollution sources
in Oregon do not significantly contribute to nonattainment of the 1997
PM2.5 NAAQS in other states.
    EPA does not necessarily agree that Oregon's methodology is
adequate for purposes of a section 110(a)(2)(D)(i) analysis. Therefore,
EPA is supplementing the State's submission with additional, and more
recent, information in order to assess this issue more fully. As noted
above, EPA is evaluating the 2010 interstate transport SIP taking into
account methodologies and analyses for the identification of the
receptor monitors that was developed in the Transport Rule Proposal, as
well as EPA's projections of future air quality at monitors in western
states in the Timin Memo, and air quality data from monitors in the
states bordering Oregon. Although each of the factors considered in the
following analysis are not in and of themselves determinative,
consideration of these factors together provides a reliable qualitative
conclusion that emissions from Oregon do not contribute significantly
to nonattainment of the PM2.5 NAAQS at monitors in other
states.
    Specifically, we identified the nonattainment receptors for the
1997 annual PM2.5 NAAQS closest to Oregon to evaluate
whether emissions from Oregon sources contribute significantly to
nonattainment of the 1997 PM2.5 NAAQS in any other
state.\29\ For the 1997 annual PM2.5 NAAQS, the projected
nonattainment receptors closest to Oregon that EPA identified from the
modeling analyses conducted for the Transport Rule Proposal are all
east of the Mississippi River.\30\ Given the significant distance
between Oregon and these nonattainment receptors and the intervening
mountainous terrain, we believe it is reasonable to conclude that
Oregon sources do not significantly contribute to nonattainment of the
1997 annual PM2.5 NAAQS in any of these areas.
---------------------------------------------------------------------------

    \29\ For PM2.5, the Transport Rule Proposal
identified nonattainment receptors for the 1997 annual
PM2.5 NAAQS and the 2006 24-hour PM2.5 NAAQS.
See 75 FR 45210 at 45212. Because our proposal on Oregon's 2010
Interstate transport SIP addresses requirements of CAA section
110(a)(2)(D)(i) only for purposes of the 1997 ozone and
PM2.5 NAAQS, for PM2.5 purposes we consider
only the nonattainment receptors for the 1997 annual
PM2.5 NAAQS identified in the Transport Rule Proposal.
    \30\ Specifically, the nonattainment receptors for the 1997
annual PM2.5 standard are located in Alabama, Georgia,
Illinois, Indiana, Kentucky, Michigan, Ohio, Pennsylvania, and West
Virginia. See Transport Rule Proposal, 75 FR 45210 at 45247-45248
(August 2, 2010).
---------------------------------------------------------------------------

    To address the potential for PM2.5 transport among
western states, EPA also relied on the additional analysis in the Timin
Memo identifying monitors projected to record violations of the 1997
annual PM2.5 NAAQS. The Timin Memo identified predicted
future nonattainment receptors for the 1997 annual PM2.5
NAAQS in southern and central California but did not identify predicted
future nonattainment receptors for the 1997 annual PM2.5
NAAQS in any other western state.\31\ For Oregon, the closest
nonattainment receptor in California for the 1997 annual
PM2.5 NAAQS was Fresno County. Fresno County is over 300
miles south of the closest point on Oregon's border and is on the other
side of intervening mountain ranges that act as a natural barrier to
air pollution transport. Although not determinative by themselves,
distance and topography are not favorable to PM2.5 transport
from Oregon to central California. In addition, prevailing winds in the
west generally move from south-westerly, westerly, or north-westerly
directions, as indicated by the typical movement of weather systems.
Hence central and southern California are not in the predominant
direction of winds from Oregon. Given the distance between the Oregon
border and central and southern California nonattainment receptors, the
intervening mountainous topography, and the general westerly direction
of transport winds in the Western U.S., EPA concludes that Oregon
sources do not contribute significantly to nonattainment of the 1997
annual PM2.5 NAAQS in Fresno County or to any more distant
nonattainment receptors in California. EPA's analysis for western
states therefore supports our proposal to conclude that Oregon sources
do not contribute significantly to nonattainment of the 1997 annual
PM2.5 NAAQS in any other state.
---------------------------------------------------------------------------

    \31\ See Timin Memo at Appendix B (``Base year 2003-2007 and
Future Year 2012 8-Hour Average Ozone Design Values--Western
States'').
---------------------------------------------------------------------------

    The analysis for the Transport Rule Proposal did not identify any
nonattainment receptors for the 1997 24-hour PM2.5 NAAQS in
the portions of the U.S. covered by the Transport Rule Proposal
modeling domain (i.e., the 12 km grid covering the continental U.S.
east of the Rockies).\32\ Recent monitoring data in EPA's Air Quality
System (2007-2009 design values) indicate that the highest 24-hour
PM2.5 design value in the 47 states of the continental U.S.
(excluding California) is 50 [mu]g/m\3\,\33\ which is well below the
level of the 1997 24-hour PM2.5 NAAQS of 65 [mu]g/m\3\. In
California, 2007-2009 AQS data indicate that only one area, Kern
County, has a design value above the level of the 1997 24-hour
PM2.5 NAAQS. As discussed above, EPA believes that given the
relatively long distance between the Oregon border and Kern County, the
intervening mountainous topography, and the generally westerly
direction of transport winds in the Western U.S., emissions from Oregon
sources do not interfere with maintenance of the 1997 24-hour
PM2.5 NAAQS in Kern County. These data and factors further
support our proposed finding that Oregon sources do not significantly
contribute to nonattainment of the 1997 24-hour PM2.5 NAAQS
in any other state.
---------------------------------------------------------------------------

    \32\ 75 FR 45210 at 45249-45251 (August 2, 2010).
    \33\ These values were recorded at monitors in Liberty-Clairton,
Pennsylvania and Provo, Utah. See http://epa.gov/airtrends/pdfs/PM2.5%202007-2009%20design%20value%20update.pdf. Data from EPA's Air
Quality System can be viewed at http://www.epa.gov/ttn/airs/airsaqs/.
---------------------------------------------------------------------------

    In addition to the information in the 2010 interstate transport SIP
and our review of the nearest nonattainment receptors identified from
the modeling analyses conducted for the Transport Rule Proposal, EPA
evaluated air quality data for the areas in states bordering Oregon
that are designated nonattainment for the 1997 PM2.5

NAAQS. Although significant contribution must be measured not just
against nonattainment areas but also against areas with monitors
showing violations of the NAAQS, nonattainment areas are a convenient
point of analysis.
    The closest 1997 PM2.5 nonattainment area in any state
bordering Oregon is the San Joaquin Valley in California.\34\ This
nonattainment area is located in central California and is over 250
miles from the closest point on Oregon's border and on the other side
of intervening mountain ranges that act as a natural barrier to air
pollution transport. In addition, prevailing winds in the western U.S.
generally move from south-westerly, westerly, or north-westerly
directions, as indicated by the typical movement of weather systems.
Hence, Joaquin Valley, California, is not in the predominant direction
of winds from Oregon. Given the relatively long distance between Oregon
and the San Joaquin Valley, the intervening mountainous topography, and
the general direction of transport winds in the Western U.S., EPA
believes that Oregon sources do not significantly contribute to
nonattainment of the 1997 PM2.5 NAAQS in the San Joaquin
Valley nonattainment area or to any more distant California 1997
PM2.5 nonattainment areas. There are no areas in Idaho and
Washington currently designated nonattainment for the 1997
PM2.5 NAAQS. This is further support that Oregon sources do
not contribute significantly to nonattainment of the 1997
PM2.5 NAAQS in any other state.
---------------------------------------------------------------------------

    \34\ In 2005, EPA designated this area nonattainment for
violations of the 1997 and annual PM2.5 NAAQS. 70 FR 944
(January 5, 2005), and 40 CFR 81.305.
---------------------------------------------------------------------------

    Although not located in a state bordering Oregon, the closest
designated nonattainment area to Oregon for the 1997 PM2.5
NAAQS is Libby, in Lincoln County, Montana.\35\ In 2005, EPA designated
this area nonattainment for the 1997 annual PM2.5 NAAQS. 70
FR 944 (January 5, 2005) and 40 CFR 81.327. A number of factors provide
evidence that Oregon emissions do not significantly contribute to past
violations of the 1997 annual PM2.5 standards in Libby,
Montana.
---------------------------------------------------------------------------

    \35\ Libby is in a narrow valley surrounded by mountains 4,000
feet higher than the town. The Rocky Mountain Range to the west of
Libby (and east of the Idaho border) reaches summit elevations of
12,000 feet with most summit elevations between 6000 and 7000 feet
that act as a barrier to air movement between Idaho and Montana.
---------------------------------------------------------------------------

    First, in the process of designating Libby nonattainment for both
the 1997 PM2.5 NAAQS and the 2006 24-hour PM2.5
NAAQS, EPA noted the predominantly local origins of PM2.5
nonattainment in Libby.36 37 Residential wood-burning stoves
during the winter-time, when frequent and persistent temperature
inversions occurred, were specifically identified as a key source of PM
emissions. The fact that nonattainment in a given area is primarily the
result of local emissions sources does not, however, exclude the
possibility of significant contribution to nonattainment from
interstate transport. EPA believes that other evidence supports the
conclusion that emissions from Oregon sources are not significantly
contributing to violations in Libby, Montana.
---------------------------------------------------------------------------

    \36\ ``Technical Support for State and Tribal Air Quality Fine
Particle (PM2.5) Designations,'' (for Montana) Chapter 6,
pp. 347-352, December 2004.
    \37\ ``Technical Support for State and Tribal Air Quality Fine
Particle (PM2.5) Designations,'' (for Montana) Chapter
4.8.1, pp. 1-15, December 2008.
---------------------------------------------------------------------------

    Second, monitoring data from 1999 through 2009 from areas outside
of Libby in Montana support a determination that Oregon does not
significantly contribute to nonattainment in Libby. At all other sites
in Montana, annual PM2.5 design value levels have remained
below the 15 [mu]g/m\3\ nonattainment threshold. Annual
PM2.5 design values for this period for most of these
monitors remained at levels equal to, or less than, two-thirds of the
1997 annual PM2.5 NAAQS. Even the three highest design
values at these monitors were 20 percent below the level of the annual
standard.\38\ The lower PM2.5 levels elsewhere in Montana
are evidence that local sources, and not interstate transport, are key
contributors to past nonattainment in Libby.
---------------------------------------------------------------------------

    \38\ In 2001, 2002 and 2006, design values for two monitors in
Missoula County were 11.1, 11.4 and 11.8 [mu]g/m\3\. Computed from
AQS monitoring data. 75 FR 16028 (March 31, 2010).
---------------------------------------------------------------------------

    Third, for 2007-2009, AQS data show that the annual
PM2.5 design values for the Libby nonattainment area
themselves fell below the levels of the NAAQS. This reduction has been
attributed to an effective wood stove replacement program that
decreased PM2.5 emissions by approximately 59 percent.\39\
In other words, even if emissions from Oregon sources were reaching
Libby, they would not significantly contribute to violations of the
1997 annual PM2.5 NAAQS because monitoring data demonstrate
that Libby is not violating the 1997 annual PM2.5 NAAQS.
---------------------------------------------------------------------------

    \39\ State of Montana, Department of Environmental Quality,
``State Implementation Plan-Libby Annual PM2.5 Control
Plan,'' submitted to EPA April 1, 2008.
---------------------------------------------------------------------------

    Finally, EPA's conclusion that emissions from Oregon do not
significantly contribute to nonattainment in Libby, Montana, is further
supported by the analysis of monitors in the western United States.\40\
This analysis concludes that in 2012 the average annual
PM2.5 design values in Lincoln County, Montana will be below
the threshold for consideration as a nonattainment receptor. These
factors together support a conclusion that Oregon sources do not
contribute significantly to nonattainment of the 1997 annual
PM2.5 NAAQS in the Libby 1997 PM2.5 nonattainment
area.
---------------------------------------------------------------------------

    \40\ See Timin Memo at Appendix A (``Base year 2003-20007 and
Future Year 2012 Annual Average PM2.5 Design Values--
Western States'').
---------------------------------------------------------------------------

    As mentioned above, EPA considers not only significant contribution
to designated nonattainment areas, but also significant contribution to
areas with monitors showing violations of the NAAQS. A review of the
most recent three years (2007-2009) of monitoring data in AQS for the
bordering states of Washington, Idaho, Nevada, and California shows
that the only monitors with design values above the 1997 annual
PM2.5 NAAQS are located in central and southern California.
The county closest to the Oregon border that has a design value above
the 1997 annual PM2.5 NAAQS is Kern County, California. Kern
County is more than 400 miles from the closest point on Oregon's border
and is on the other side of intervening mountain ranges that act as a
natural barrier to air pollution transport. Although not determinative
by themselves, distance and topography are not favorable to
PM2.5 transport from Oregon to central California. In
addition, prevailing winds in the west generally move from south-
westerly, westerly, or north-westerly directions, as indicated by the
typical movement of weather systems. Hence Kern County, California is
not in the predominant direction of winds from Oregon. Given the
relatively long distance between the Oregon border and Kern County, the
intervening mountainous topography, and the generally westerly
direction of transport winds in the Western U.S., it is reasonable to
conclude that Oregon sources do not significantly contribute to
nonattainment of the 1997 PM2.5 NAAQS in Kern County or to
any more distant monitors in California.
    As noted above no monitors in Washington, Idaho and Nevada or
Northern California had design values above the 1997 annual
PM2.5 NAAQS for the 2007-2009 period. The fact that monitors
in these areas are not registering violations of the 1997
PM2.5 NAAQS does not in itself conclusively establish that
emissions from Oregon could not contribute in the aggregate to

violations in these areas. But this fact combined with our above
evaluation of the nearest nonattainment receptors, nearest
nonattainment areas, and nearest monitors with design values above the
1997 annual PM2.5 NAAQS, supports a conclusion that Oregon
sources do not significantly contribute to nonattainment of the 1997
PM2.5 NAAQS in other states.
    Finally, none of the PM2.5 monitors in Oregon have
themselves indicated a violation of the 1997 annual PM2.5
NAAQS. The absence of violations in Oregon itself does not rule out the
possibility of transport, but taken in conjunction with other relevant
information, including the distance from Oregon to areas with design
values above the 1997 annual PM2.5 NAAQS and Pacific
Northwest meteorology and topography, this fact helps to support the
conclusion that there is no transport from Oregon resulting in
significant contribution to nonattainment in another state. Taking into
account the total weight of all of the factors discussed above, EPA
concludes that Oregon does not significantly contribute to the 1997
annual PM2.5 NAAQS nonattainment in any other state.
3. Conclusion Regarding Significant Contribution to Nonattainment
    Based on the weight of evidence discussed above, including the
location of the nearest projected nonattainment receptors, distance to
the nearest designated PM2.5 nonattainment area,
meteorology, topography, and recent air quality monitoring data, we
propose to determine that Oregon's 2010 interstate transport SIP is
adequate to ensure that emissions from Oregon do not significantly
contribute to nonattainment in any other state for the 1997 8-hour
ozone or 1997 PM2.5 NAAQS, consistent with the requirements
of CAA section 110(a)(2)(D)(i)(I). Thus, we propose to determine that
Oregon's SIP includes the measures necessary to prevent such prohibited
interstate transport impacts for these NAAQS.

B. EPA's Evaluation of Interference With Maintenance

    This proposed approval evaluates the interfere with maintenance
element of section of section 110(a)(2)(D)(i)(I) for the 1997 8-hour
ozone and 1997 PM2.5 NAAQS in several ways. It takes into
account Oregon's 2010 interstate transport SIP, in which the State
explains that based on meteorological and other characteristics in
Oregon and in the surrounding areas, PM2.5 and ozone
precursor emissions do not interfere with maintenance of the 1997 8-
hour ozone or 1997 PM2.5 NAAQS in other states.\41\ In
addition, EPA has supplemented the State's analysis with its own
evaluation of the evidence, including a review of the nearest monitors
in other states that are appropriate maintenance receptors, consistent
with EPA's approach in the Transport Rule Proposal, in order to assess
whether emissions sources in Oregon interfere with maintenance of the
1997 8-hour ozone and PM2.5 NAAQS in other states.
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    \41\ Oregon's submission makes this conclusion with respect to
not only the 1997 PM2.5 NAAQS and 1997 8-hour ozone
NAAQS, but also the 2006 PM2.5 NAAQS and the 2008 8-hour
ozone NAAQS.
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1. Oregon's 2010 Interstate Transport SIP
    To show that Oregon emissions, as controlled under its SIP, do not
interfere with maintenance of the 1997 8-hour ozone NAAQS and 1997
PM2.5 NAAQS in another state, Oregon's 2010 interstate
transport SIP analyzed several types of factors to support its
assertion. First, the State pointed to topography and meteorology for
its evaluation, maintaining that high PM2.5 concentrations
in adjacent states typically occur under winter conditions when air
speeds are low and/or localized air inversions occur. Describing wind
direction as being typically variable with the majority of wind speeds
less than 8 miles per hour, and a significant portion of low winds less
than 5 miles per hour, the state noted that these low wind speeds and
air stagnation conditions do not lend them to long distance air
pollution transport. The State indicated that there are occasional high
8-hour ozone levels that occur in the summer months, but maintained
that prevailing winds\42\ in Oregon are predominantly from the north to
northwest.\43\ The state indicated that prevailing summer winds could
theoretically result in some interstate transport of ozone forming
emission from Oregon to western Idaho, Nevada and northern California.
It also noted, however, that significant distances and topography (such
as major mountain ranges that separate Oregon from California, Idaho,
and Nevada) would likely minimize the significance of these impacts on
other states. It pointed to, for example, the approximately 400 to 700
miles distance between the largest major urban center in Oregon (the
greater Portland area) and urban areas in western Idaho, Nevada, and
northern California and at least one major mountain range between those
areas.
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    \42\ This north/northwest prevailing wind direction was derived
from surface level winds and airport data and is not necessarily
indicative of the prevailing wind direction of typical weather
systems in the west.
    \43\ There are currently no 1997 8-hour ozone nonattainment
areas in Oregon or Washington.
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    Second, Oregon used AQS monitoring data for 2006-2008 from other
states in its analysis. Oregon pointed out that both PM2.5
and ozone design values in all counties adjacent to Oregon are below
the PM2.5 and 8-hour ozone NAAQS. Oregon also consulted with
each of the state air agencies for Washington, Idaho, Nevada, and
California to get a sense of what the local air agencies believe are
the likely causes of any air quality concerns for maintaining
compliance with the PM2.5 and ozone NAAQS. Based on these
consultations and the other information above, Oregon concluded that
emissions from air pollution sources in Oregon do not interfere with
the maintenance of the 8-hour ozone or PM2.5 NAAQS in other
states.
    Oregon also relied on information about air stagnation conditions
in other states to support its assertions that Oregon sources do not
interfere with maintenance of the 1997 8-hour ozone NAAQS and 1997
PM2.5 NAAQS in other states. Oregon noted that stagnant air
conditions are associated with weak transport and that high
PM2.5 concentrations in adjacent states typically occur
under winter conditions when air speeds are low and/or localized air
inversions occur. Oregon also pointed to examples of where it has
collaborated with other states to demonstrate its ability and
willingness to address problems involving interstate transport.
Examples included the Portland-Vancouver 1-hour ozone attainment and
maintenance plans, and Oregon's regional haze plan. Oregon described
how in the mid-1990s and again in 2007, ODEQ collaborated with the
Southwest Clean Air Agency (i.e., the State of Washington air agency
with jurisdiction over Vancouver) to develop bi-state ozone attainment
and maintenance plans with emission reduction strategies needed to
attain and maintain compliance with federal ozone standards. In 2008-
09, ODEQ worked with the states of Washington, Idaho and California, as
well as Federal Land Managers in developing Oregon's Regional Haze
plan. Oregon described how under that plan ODEQ adopted several
emission reduction strategies, including emission control requirements
to reduce the interstate transport of haze forming emissions.
    Finally, Oregon pointed to its section 110 infrastructure SIP to
show that ODEQ has the ability to participate as needed in future
studies on regional air pollution issues, or collaborate with

other states if air quality concerns are identified that require a
case-specific evaluation of interstate transport. Oregon added that its
infrastructure SIP also ensures the legal mechanism for ODEQ to take
action as needed to reduce emissions to help maintain compliance with
federal NAAQS.
    EPA does not necessarily agree that Oregon's methodology is
adequate for purposes of a section 110(a)(2)(D)(i) analysis. Therefore,
EPA is supplementing the State's submission with additional, and more
recent, information in order to assess this issue more fully. As noted
above, EPA is evaluating the 2010 interstate transport SIP taking into
account methodologies and analyses for the identification of the
receptor monitors that was developed in the Transport Rule Proposal, as
well as EPA's projections of future air quality at monitors in western
states in the Timin Memo and preliminary air quality data from monitors
in the states bordering Oregon. Although each of the factors considered
in the following analysis are not in and of themselves determinative,
consideration of these factors together provides a reliable qualitative
conclusion that emissions from Oregon do not interfere with maintenance
of the 1997 8-hour ozone and PM2.5 NAAQS at monitors in
other states.
2. Interfere With Maintenance Evaluation for the 8-Hour Ozone NAAQS
    As discussed above, in the Transport Rule Proposal, EPA projected
future concentrations of ozone at monitors to identify areas that are
expected to be violating the NAAQS or to have difficulty maintaining
compliance with the NAAQS in 2012. For purposes of the interference
with maintenance evaluation, EPA projected future concentrations of
ozone at monitors to identify areas that are expected to have a maximum
design value (based on a single 3-year period) that exceeds the 1997 8-
hour ozone NAAQS, and EPA anticipates that by 2012 these maintenance
receptors will have difficulty in maintaining attainment of the NAAQS
if there are adverse variations in meteorology or emissions.
    To identify the states with emissions that may cause interference
with maintenance of the NAAQS at maintenance receptors, the Transport
Rule Proposal modeled the states' contributions to ambient ozone levels
at these maintenance receptors.\44\ Because the Transport Rule Proposal
did not identify the contribution of emissions from Oregon (and other
western states not fully inside the Transport Rule Proposal's modeling
domain) to 8-hour ozone maintenance receptors in other states, our
assessment relies on a weight of evidence approach that considers
relevant information from the Transport Rule Proposal pertaining to
states within its modeling domain, and additional information such as
geographical and meteorological factors, EPA's projections of future
air quality at monitors in western states in the Timin Memo, and AQS
monitoring data. Although each of the factors considered in the
following analysis is not in and of itself determinative, consideration
of these factors together supports a reliable qualitative conclusion
that emissions from Oregon do not interfere with maintenance of the
1997 8-hour ozone NAAQS at monitors in other states.
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    \44\ See Transport Rule Proposal, 75 FR 45210 at 45253-45273.
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    Our analysis begins by assessing Oregon's contribution to the
closest maintenance receptors for the 1997 8-hour ozone standard. The
Transport Rule Proposal identifies 16 maintenance receptors for the
1997 8-hour ozone standard within its modeling domain (consisting of 37
states east of the Rocky Mountains, and the District of Columbia). Of
these, the receptors closest to Oregon are eight receptors in the
Dallas-Fort Worth and Houston-Galveston-Brazoria 8-hour ozone
nonattainment areas in eastern Texas. The remaining eight maintenance
receptors are located in Connecticut, Georgia, New York and
Pennsylvania.\45\
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    \45\ See Transport Rule Proposal, Table IV.C-12, 75 FR 45210 at
45252-45253.
---------------------------------------------------------------------------

    As discussed above in section V.A.1, the Dallas-Fort Worth and
Houston areas are over 1200 miles from the closest point on Oregon's
border. The maintenance receptor monitors located in Connecticut,
Georgia, New York and Pennsylvania are significantly further away.
Although distance alone is not determinative in the analysis of
potential ozone transport, with increasing distance there are greater
opportunities for ozone and NOX dispersion and/or removal
from the atmosphere. Moreover, the intervening Rocky Mountains act as a
natural barrier to air pollution transport. These factors together
support a conclusion that emissions from Oregon sources do not
interfere with maintenance of the 1997 8-hour ozone NAAQS in the
nearest areas with monitors projected to violate the 1997 8-hour ozone
NAAQS as part of the Transport Rule Proposal.
    EPA's analysis in the Timin Memo identified four maintenance
receptors for the 1997 8-hour ozone NAAQS in southern and central
California.\46\ The closest 8-hour ozone maintenance receptor to Oregon
was in Placer County, California. Placer County is approximately 185
miles south of the closest point on Oregon's border and is not in the
predominant direction of transport winds. As noted earlier, prevailing
winds generally move from south-westerly, westerly, or northwesterly
directions, as indicated by the typical movement of weather systems.
Given the relatively long distance between Oregon and central
California, the intervening mountainous topography, and the general
direction of west-to-east transport winds across Oregon, it is
reasonable to conclude that Oregon sources do not interfere with
maintenance of the 1997 8-hour ozone NAAQS in Placer County,
California. It is also reasonable to conclude that emissions from
sources in Oregon would not have such impacts at other identified
maintenance receptor sites that are in central or southern California
that are in the same direction and further away from the Oregon border.
All of these factors taken together supports a conclusion that
emissions from Oregon sources do not interfere with maintenance of the
1997 8-hour ozone NAAQS in any other state.
---------------------------------------------------------------------------

    \46\ See Timin Memo at Appendix B (``Base year 2003-2007 and
Future Year 2012 8-Hour Average Ozone Design Values--Western
States'').
---------------------------------------------------------------------------

    Finally, none of the ozone monitors in Oregon have themselves
indicated a violation of the 1997 8-hour ozone NAAQS. The absence of
violations in Oregon itself does not rule out the possibility of
transport, but taken in conjunction with other relevant information,
including the distance from Oregon to areas with design values above
the 1997 8-hour ozone NAAQS and Pacific Northwest meteorology and
topography, this fact helps to support a conclusion that there is no
transport from Oregon resulting in interference with maintenance in
another state. Taking into account the total weight of all of the
factors discussed above, EPA concludes that Oregon does not interfere
with maintenance of the 1997 8-hour ozone NAAQS in any other state.
3. Interference With Maintenance Evaluation for the 1997
PM2.5 NAAQS
    The Transport Rule Proposal identifies within its modeling domain
16 predicted future maintenance receptors for the 1997 annual
PM2.5 NAAQS. Of these, the closest to Oregon are receptors
located in Harris County, Texas. Harris County, Texas, is over 1,400
miles from the closest point on Oregon's border and on the other side
of

the Rocky Mountains. Given the long distance and intervening
mountainous topography between Oregon and this area, it is reasonable
to conclude that there is a very low probability that Oregon sources
interfere with maintenance in that area or at the other identified
maintenance sites east of Harris County, Texas.\47\ EPA, therefore,
concludes that Oregon sources do not interfere with maintenance of the
1997 annual PM2.5 NAAQS in other states within the
geographic region covered by the Transport Rule Proposal.
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    \47\ Specifically, the remaining 15 maintenance sites for the
1997 annual PM2.5 NAAQS are located in Kentucky, New
York, Ohio, Pennsylvania, and West Virginia.
---------------------------------------------------------------------------

    EPA's analysis in the Timin Memo identified Los Angeles County,
California, as the closest projected maintenance receptor to Oregon's
border. Los Angeles County is located almost 500 miles south of the
closest point on Oregon's border and is on the other side of
intervening mountain ranges that act as a natural barrier to air
pollution transport. Although not determinative by themselves, distance
and topography are not favorable to PM2.5 transport from
Oregon to central California. In addition, prevailing winds in the west
generally move from south-westerly, westerly, or north-westerly
directions, as indicated by the typical movement of weather systems.
Given the relatively long distance between Oregon and Los Angeles
County, the intervening mountainous topography, and the general
westerly direction of transport winds in the Western U.S., it is
reasonable to conclude that Oregon sources do not interfere with
maintenance of the 1997 annual PM2.5 NAAQS in Los Angeles
County or to any more distant maintenance receptors in central or
southern California. EPA's analysis for the western states therefore
supports our proposal to conclude that Oregon sources do not interfere
with maintenance of the 1997 annual PM2.5 NAAQS in any other
states. Based on all of these factors taken together, EPA further
believes it is reasonable to conclude that Oregon emissions under the
SIP do not interfere with maintenance of the 1997 PM2.5
NAAQS in any other state.
    The analysis for the Transport Rule Proposal did not identify any
maintenance receptors for the 1997 24-hour PM2.5 NAAQS in
the portions of the U.S. covered by the Transport Rule Proposal
modeling domain.\48\ Recent monitoring data in EPA's AQS Database
(2007-2009 design values that are under final EPA review) indicate that
the highest 24-hour PM2.5 design value in the 47 states of
the continental U.S. (excluding California) is 50 [micro]g/m\3\, which
is well below the level of the 1997 24-hour PM2.5 NAAQS of
65 [micro]g/m\3\.\49\ For California, AQS data indicate that only Kern
County has a 24-hour design value above the level of the 1997 24-hour
PM2.5 NAAQS. As discussed above, EPA believes that, based on
the relatively long distance between the Oregon border and Kern County,
the intervening mountainous topography, and the generally westerly
direction of transport winds in the Western U.S., emissions from Oregon
sources do not interfere with maintenance of the 1997 24-hour
PM2.5 NAAQS in Kern County.
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    \48\ 75 FR 45210 at 45249-45251 (August 2, 2010). See also fn.
39 and fn. 47.
    \49\ Data from EPA's Air Quality System can be viewed at http://www.epa.gov/ttn/airs/airsaqs/.
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4. Conclusion Regarding Interference With Maintenance
    Based on the weight of evidence, including the location of the
nearest projected maintenance sites, taking into account distance,
meteorology, topography, and recent air quality monitoring data, as
discussed above, we propose to determine that Oregon's 2010 interstate
transport SIP is adequate and that emissions from Oregon do not
interfere with maintenance in any other state for the 1997 8-hour ozone
or 1997 PM2.5 NAAQS, consistent with the requirements of
element (2) of CAA section 110(a)(2)(D)(i)(I). Thus, we propose to
determine that Oregon's SIP contains adequate provisions necessary to
prevent such prohibited interstate transport impacts for these NAAQS
and does not require any additional measures for this purpose at this
time.

VI. Proposed Action

    In light of the data and the weight of evidence analysis presented
above, EPA is proposing to approve revisions to the Oregon SIP,
submitted on June 23, 2010, and December 23, 2010, and concludes that
for the 1997 8-hour ozone and 1997 PM2.5 NAAQS, air
pollutant emissions from sources within Oregon do not either (1)
significantly contribute to nonattainment of the NAAQS in any other
state; or (2) interfere with maintenance of the NAAQS by any other
state.
    As noted previously, EPA will address element (3) interference with
any other state's required measures to prevent significant
deterioration of its air quality and element (4), interference with any
other state's required measures to protect visibility, in a separate
action. EPA will also take action on the portion of Oregon's SIP that
addresses the 2006 PM2.5 and 2008 8-hour ozone NAAQS in a
separate action.

VII. 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
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, Incorporation by
reference, Intergovernmental relations, Ozone, Particulate matter,
Reporting and recordkeeping requirements, Volatile organic compounds.

    Dated: March 30, 2011.
Dennis J. McLerran,
Regional Administrator, Region 10.
[FR Doc. 2011-8330 Filed 4-6-11; 8:45 am]
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