[Federal Register Volume 75, Number 180 (Friday, September 17, 2010)]
[Proposed Rules]
[Pages 56928-56935]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2010-23292]
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ENVIRONMENTAL PROTECTION AGENCY
40 CFR Part 52
[EPA-R08-OAR-2009-0557; FRL-9202-8]
Approval and Promulgation of State Implementation Plan Revisions;
State of North Dakota; Interstate Transport of Pollution for the 1997
PM2.5 and 8-hour Ozone NAAQS: ``Interference With
Maintenance'' Requirements
AGENCY: Environmental Protection Agency (EPA).
ACTION: Proposed rule.
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SUMMARY: The Environmental Protection Agency is proposing partial
approval of the State Implementation Plan (SIP) revisions called
``Interstate Transport of Air Pollution'' addressing the ``interference
with maintenance'' requirement of Clean Air Act (CAA) section
110(a)(2)(D)(i) for the 1997 fine particulate matter (PM2.5)
and 8-hour ozone National Ambient Air Quality Standards (NAAQS). In
this action EPA proposes to approve the North Dakota Interstate
Transport SIP sections that address the requirements of section
110(a)(2)(D)(i) prohibiting a state's emissions from interfering with
maintenance by any other state of the 1997 PM2.5 and 8-hour
ozone NAAQS. This action is being taken under section 110 of the CAA.
DATES: Comments must be received on or before October 18, 2010.
ADDRESSES: Submit your comments, identified by Docket ID No. EPA-R08-
OAR-2009-0557, by one of the following methods:
http://www.regulations.gov. Follow the on-line
instructions for submitting comments.
E-mail: [email protected].
Fax: (303) 312-6064 (please alert the individual listed in
the FOR FURTHER INFORMATION CONTACT if you are faxing comments).
Mail: Callie Videtich, Director, Air Program,
Environmental Protection Agency (EPA), Region 8, Mailcode 8P-AR, 1595
Wynkoop Street, Denver, Colorado 80202-1129.
Hand Delivery: Callie Videtich, Director, Air Program,
Environmental Protection Agency (EPA), Region 8, Mailcode 8P-AR, 1595
Wynkoop, Denver, Colorado 80202-1129. Such deliveries are only accepted
Monday through Friday, 8 a.m. to 4:30 p.m., excluding Federal holidays.
Special arrangements should be made for deliveries of boxed
information.
Instructions: Direct your comments to Docket ID No. EPA-R08-OAR-
2009-0557. 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 your 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. For additional instructions on submitting
comments, go to Section I. General Information of the SUPPLEMENTARY
INFORMATION section of this document.
Docket: All documents in the docket are listed in the http://www.regulations.gov index. Although listed in the index, some
information is not publicly available, e.g., CBI or other information
whose disclosure is restricted by statute. Certain other material, such
as copyrighted material, will be publicly available only in hard copy.
Publicly-available docket materials are available either electronically
in http://www.regulations.gov or in hard copy at the Air Program,
Environmental Protection Agency (EPA), Region 8, Mailcode 8P-AR, 1595
Wynkoop, Denver, Colorado 80202-1129. EPA requests that if at all
possible, you contact the individual listed in the FOR FURTHER
INFORMATION CONTACT section to view the hard copy of the docket. You
may view the hard copy of the docket Monday through Friday, 8 a.m. to 4
p.m., excluding Federal holidays.
FOR FURTHER INFORMATION CONTACT: Domenico Mastrangelo, Air Program,
U.S. Environmental Protection Agency, Region 8, Mailcode 8P-AR, 1595
Wynkoop, Denver, Colorado 80202-1129, (303) 312-6436,
[email protected].
SUPPLEMENTARY INFORMATION:
Definitions
For the purpose of this document, we are giving meaning to certain
words or initials as follows:
(i) The words or initials Act or CAA mean or refer to the Clean Air
Act, unless the context indicates otherwise.
[[Page 56929]]
(ii) The words EPA, we, us or our mean or refer to the United
States Environmental Protection Agency.
(iii) The initials SIP mean or refer to State Implementation Plan.
(iv) The words North Dakota and State mean the State of North
Dakota.
Table of Contents
I. General Information
What should I consider as I prepare my comments for EPA?
II. Background
III. What action is EPA proposing?
IV. What is the State process to submit this material to EPA?
V. EPA's Review and Technical Information
A. EPA's Evaluation of Interference with Maintenance
B. North Dakota Transport SIP
VI. Proposed Action
VII. Statutory and Executive Order Reviews
I. General Information
What should I consider as I prepare my comments for EPA?
1. Submitting CBI. Do not submit CBI to EPA through http://www.regulations.gov or e-mail. Clearly mark the part or all of the
information that you claim to be CBI. For CBI information in a disk or
CD ROM that you mail to EPA, mark the outside of the disk or CD ROM as
CBI and then identify electronically within the disk or CD ROM the
specific information that is claimed as CBI. In addition to one
complete version of the comment that includes information claimed as
CBI, a copy of the comment that does not contain the information
claimed as CBI must be submitted for inclusion in the public docket.
Information so marked will not be disclosed except in accordance with
procedures set forth in 40 CFR part 2.
2. Tips for Preparing Your Comments. When submitting comments,
remember to:
Identify the rulemaking by docket number and other identifying
information (subject heading, Federal Register date and page number).
Follow directions--The agency may ask you to respond to specific
questions or organize comments by referencing a Code of Federal
Regulations (CFR) part or section number.
Explain why you agree or disagree; suggest alternatives and substitute
language for your requested changes.
Describe any assumptions and provide any technical information and/or
data that you used.
If you estimate potential costs or burdens, explain how you arrived at
your estimate in sufficient detail to allow for it to be reproduced.
Provide specific examples to illustrate your concerns, and suggest
alternatives.
Explain your views as clearly as possible, avoiding the use of
profanity or personal threats.
Make sure to submit your comments by the comment period deadline
identified.
II. Background
On July 18, 1997, EPA promulgated new NAAQS for ozone and for
PM2.5. This action is being taken in response to the
promulgation of the 1997 PM2.5 and 8-hour ozone NAAQS. This
action does not address the requirements for the 2006 24-hour
PM2.5 or 2008 8-hour ozone NAAQS; those standards will be
addressed in later actions.
Section 110(a)(1) of the CAA requires states to submit SIPs to
address a new or revised NAAQS within 3 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 its ``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'' (2006 Guidance). EPA developed the 2006 Guidance to make
recommendations to states for making submissions to meet the
requirements of section 110(a)(2)(D)(i) for the 1997 8-hour ozone
standards and the 1997 PM2.5 standards.
As identified in the 2006 Guidance, the ``good neighbor''
provisions in section 110(a)(2)(D)(i) 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) contains four
distinct requirements related to the impacts of interstate transport.
The SIP must prevent sources in the state from emitting pollutants in
amounts which will: (1) Contribute significantly to nonattainment of
the NAAQS in other states; (2) interfere with maintenance of the NAAQS
in other states; (3) interfere with provisions to prevent significant
deterioration of air quality in other states; or (4) interfere with
efforts to protect visibility in other states.
On April 6, 2009, EPA received a SIP revision from the State of
North Dakota intended to address the requirements of section
110(a)(2)(D)(i) for both the 1997 8-hour ozone standards and the 1997
PM2.5 standards. In this rulemaking, EPA is addressing only
the requirements that pertain to preventing sources in North Dakota
from emitting pollutants that will interfere with maintenance of the
1997 8-hour ozone NAAQS and the 1997 PM2.5 NAAQS by other
states. In its submission, the State of North Dakota indicated that its
current SIP is adequate to prevent such interference. With this
submission, the state intended to meet the recommendations of the 2006
Guidance for SIP submissions to meet the second element of section
110(a)(2)(D)(i) for the 1997 PM2.5 and 8-hour ozone
standards.
III. What action is EPA proposing?
EPA is proposing partial approval of the North Dakota Interstate
Transport of Air Pollution SIP for the 1997 PM2.5 and 8-hour
ozone NAAQS. The addition to the North Dakota SIP of section 7.8,
``Interstate Transport of Air Pollution,'' was adopted by the State of
North Dakota on April 1, 2009 and submitted to EPA on April 6, 2009.
EPA is proposing to approve the language and demonstrations of the
North Dakota Interstate Transport SIP that address element (2) of
section 110(a)(2)(D)(i), i.e., the prohibition of interference with
maintenance of the 1997 8-hour ozone NAAQS and the 1997
PM2.5 NAAQS by any other state.
IV. What is the State process to submit this material to EPA?
Section 110(k) of the CAA addresses EPA's rulemaking action on SIP
submissions by states. The CAA requires states to observe certain
procedural requirements in developing SIP revisions for submittal to
EPA. Section 110(a)(2) of the CAA requires that each SIP revision be
adopted after reasonable notice and public hearing. This must occur
prior to the revision being submitted by a state to EPA.
The North Dakota Department of Health (NDDH) held a public hearing
on October 7, 2008 for the addition to the North Dakota SIP of the
Interstate Transport non-regulatory provisions. The NDDH adopted the
provisions on April 1, 2009 and submitted them to EPA on April 6, 2009.
EPA has reviewed the submittal by the NDDH and has determined that
the State met the requirements for reasonable notice and public hearing
under section 110(a)(2) of the CAA.
V. EPA's Review and Technical Information
A. EPA's Evaluation of Interference With Maintenance
The second element of section 110(a)(2)(D)(i) requires that a
state's SIP must prohibit any source or other type
[[Page 56930]]
of emissions activity in the state from emitting pollutants that would
``interfere with maintenance'' of the applicable NAAQS by any other
state. This term is not defined in the statute. Therefore, EPA has
interpreted this term in past regulatory actions, such as the 1998
NOX SIP Call, in which EPA took action to eliminate
emissions of NOX that significantly contributed to
nonattainment, or interfered with maintenance of, the then applicable
ozone NAAQS through interstate transport of NOX and the
resulting ozone.\1\ 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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\1\ See, 63 FR 57356 (October 27, 1998). EPA's general approach
to section 110(a)(2)(D) 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 U.S. and therefore
developed the 2005 Clean Air Interstate Rule (CAIR) to address
emissions of SO2 and NOX that exacerbate ambient
ozone and PM2.5 levels in many downwind areas through
interstate transport.\2\ Within CAIR, EPA likewise 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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\2\ See, 70 FR 25162 (May 12, 2005).
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EPA's 2006 Guidance addressed 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 not within the CAIR region, EPA recommended that
states evaluate whether or not emissions from their sources would
``interfere with maintenance'' by 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.'' \3\ 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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\3\ 2006 Guidance at 5.
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In 2008, however, the U.S. Court of Appeals for the DC Circuit
found that CAIR and the related CAIR Federal implementation plans were
unlawful.\4\ 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. The court 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.'' \5\ EPA's approach, the court reasoned, would leave
areas that are ``barely meeting attainment'' with ``no recourse'' to
address upwind emissions sources.\6\ 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) and that the approach used by EPA in CAIR failed
to do so.
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\4\ See, North Carolina v. EPA, 531 F.3d 896 (DC Cir. 2008).
\5\ Id. at 909.
\6\ Id.
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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 interference 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. States such as North Dakota developed and adopted their
Interstate Transport SIP not long after the Court's July 2008 decision,
but well before EPA, in the Transport Rule Proposal (see below), was
able to propose a new approach for the interference with maintenance
element. Without recommendations from EPA, North Dakota's SIP may not
have sufficiently differentiated between the significant contribution
to nonattainment and interference with maintenance elements of the
statute, and relied in a general way on the difference between
monitored concentrations and the 1997 8-hour ozone NAAQS to evaluate
the impacts of State emissions on maintenance of the NAAQS in
neighboring states. EPA believes that it is necessary to evaluate these
state submissions for section 110(a)(2)(D)(i)(I) in such a way as to
assure that the interfere with maintenance element of the statute is
given independent meaning and is appropriately evaluated using the
types of information that EPA recommended in the 2006 Guidance. To
accomplish this, EPA believes it is necessary to use an updated
approach to this issue and to supplement the technical analysis
provided by the state in order to evaluate the submissions with respect
to the interfere with maintenance element of section 110(a)(2)(D)(i).
EPA has recently proposed a new rule to address interstate
transport 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), in order to address the
judicial remand of CAIR.\7\ As part of the Transport Rule Proposal, EPA
specifically reexamined the section 110(a)(2)(D) requirement that
emissions from sources in a state must not ``interfere with
maintenance'' of the 1997 8-hour ozone NAAQS and 1997 PM2.5
NAAQS by other states. In the proposal, EPA developed an approach to
identify areas that it predicts to be close to the level of the 1997 8-
hour ozone NAAQS and 1997 PM2.5 NAAQS in the future, and
therefore at risk to become or continue to be nonattainment for these
NAAQS 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 with interference
with maintenance, rather than with significant contribution to
nonattainment.
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\7\ See ``Federal Implementation Plans to Reduce Interstate
Transport of Fine Particulate Matter and Ozone,'' 75 FR 45210
(August 2, 2010).
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[[Page 56931]]
As described in more detail below, EPA's analysis evaluates data
from existing monitors over three overlapping three-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 with 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 interference with maintenance element of
the statute.
By this method, EPA has identified those areas with monitors that
are appropriate ``maintenance-only sites'' or maintenance ``receptors''
for evaluating whether the emissions from sources in another state
could interfere with maintenance in that particular area. EPA then uses
other analytical tools to examine the potential impacts of emissions
from upwind states on these maintenance receptors in downwind states.
EPA believes that this new approach for identifying those areas that
are predicted to have maintenance problems is appropriate to evaluate
the section 110(a)(2)(D)(i) SIP submission of a state for the
interference with maintenance element.\8\ 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
acting upon the North Dakota submission.
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\8\ 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.
These maintenance areas are at risk not to stay in attainment
because they are so close to the level of the 1997 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 as CAIR. In the
2006 Guidance, EPA stated that: ``EPA believes that the contents of the
SIP submission required by section 110(a)(2)(D)(i) 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.'' \9\ 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.\10\ 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. For the 1997 8-hour ozone NAAQS and the 1997 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.\11\ In the Transport Rule Proposal,
EPA did not calculate interstate ozone or PM2.5
contributions to or from western States.
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\9\ 2006 Guidance at 4.
\10\ Id. at 5.
\11\ See, Transport Rule Proposal, 75 FR 45210, 45277.
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Accordingly, EPA believes that section 110(a)(2)(D)(i) SIP
submissions for states not evaluated in the Transport Rule Proposal 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 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 interfere with maintenance of the 1997 8-hour ozone
and 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.
As a result, in the Transport Rule Proposal, EPA focused its
modeling on a domain including eastern states. The Transport Rule
Proposal's modeling domain includes all states east of the Rockies,
from North Dakota in the north to Texas in the south and eastward, and
its analysis results include estimates of North Dakota's contribution
to the maintenance-only sites within the Transport Rule Proposal's
modeling domain for the 1997 annual PM2.5 and 8-hour ozone
NAAQS. To reach a comprehensive determination on whether emissions from
North Dakota interfere with maintenance of the NAAQS by any other
states we use these estimated contributions in combination with other
types of information that allow us to assess whether emissions from
North Dakota interfere with maintenance of the NAAQS by states outside
the Eastern modeling domain.
B. North Dakota Transport SIP
To meet the requirements of section 110(a)(2)(D)(i), the State of
North Dakota on April 6, 2009 made a SIP submission to EPA addressing
interstate transport for the 1997 PM2.5 and the 8-hour ozone
NAAQS. EPA has previously approved this submission for purposes of the
significant contribution to nonattainment and of the interference with
PSD elements of section 110(a)(2)(D)(i).\12\ The State's submittal
focused primarily on whether emissions from North Dakota sources
significantly contribute to nonattainment of the 1997 8-hour ozone
NAAQS and 1997 PM2.5 NAAQS in other states. Following the
2006 Guidance and consistent with EPA's approach in CAIR, North Dakota
did not evaluate whether emissions from the State sources interfere
with maintenance of these NAAQS by other states separately from
significant contribution to nonattainment in other states. Instead, the
State presumed that if North Dakota sources were not significantly
contributing to violations of the NAAQS in other states, then no
further specific evaluation was necessary for purposes of the
interference with maintenance element of section 110(a)(2)(D)(i). As
explained above, however, CAIR was remanded to EPA, in part because the
court found that EPA had failed to give independent meaning to the
``interfere with maintenance'' requirement, a flaw that EPA has
remedied in the Transport Rule Proposal. However, North Dakota
submitted its Interstate Transport SIP without the benefit of EPA's new
interpretation. We therefore discuss in more detail the approach of the
Transport Rule Proposal and apply it to our assessment of whether North
Dakota's emissions interfere with maintenance of the relevant NAAQS by
any other states.
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\12\ See, 75 FR 33174 (June 11, 2010).
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Below, we discuss in greater detail relevant methods and techniques
of the
[[Page 56932]]
Transport Rule Proposal, followed by our assessment of whether
emissions from North Dakota interfere with maintenance of the 1997
PM2.5 and 8-hour ozone NAAQS.
On July 6, 2010, the EPA Administrator signed a proposed rule in
response to the judicial remand of CAIR. The Transport Rule Proposal,
published August 2, 2010, includes a new approach to determine whether
emissions from a state interfere with maintenance of the 1997 8-hour
ozone NAAQS and the 1997 PM2.5 NAAQS by other states. In
this action, EPA is using modeling results from the Transport Rule
Proposal to assess whether North Dakota emissions interfere with
maintenance of the NAAQS by states included in the proposed rule's
modeling domain. We use a comparable approach to assess whether North
Dakota interferes with maintenance of the NAAQS by western states, not
modeled for ozone or PM2.5 contributions from North Dakota.
In the Transport Rule Proposal, EPA projected future concentrations
of ozone and PM2.5 at monitors to identify areas that are
expected to be out of attainment with NAAQS or to have difficulty
maintaining compliance with the NAAQS in 2012. These areas are referred
to as nonattainment and maintenance receptors respectively. These
nonattainment and maintenance receptors are based on projections of
future air quality at existing ozone and PM2.5 monitoring
sites in those locations. EPA then used these sites as the receptors
for examining the contributions of emissions from sources located in
upwind states to nonattainment and maintenance problems at these
monitoring locations.
For ozone, EPA evaluated air quality, or ozone concentrations,
relative to the 1997 8-hour ozone NAAQS. The 1997 8-hour ozone NAAQS is
set at 0.8 parts per million. The 8-hour ozone standard is met if the
3-year average of the annual 4th highest daily maximum 8-hour ozone
concentration is less than or equal to 0.08 ppm (i.e., less than 85 ppb
based on the rounding convention in 40 CFR part 50 Appendix I). This 3-
year average is referred to as the ``design value.''
For PM2.5, EPA evaluated concentrations for both the
annual PM2.5 NAAQS and the 24-hour PM2.5 NAAQS.
The 1997 annual PM2.5 NAAQS is met when the 3-year average
of the annual mean concentration is 15.0 micrograms per cubic meter
([mu]g/m\3\) or less. The 3-year average annual mean concentration is
computed at each site by averaging the daily Federal Reference Method
(FRM) samples by quarter, averaging these quarterly averages to obtain
an annual average, and then averaging the three annual averages to get
the design value. The 1997 24-hour PM2.5 NAAQS is met when
the 3-year average of the annual 98th percentiles is 65 [mu]g/m\3\ or
less.\13\ The 3-year average mean 98th percentile concentration is
computed at each site by averaging the three individual annual 98th
percentile values at each site. The 3-year average 98th percentile
concentration is referred to as the 24-hour average design value.
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\13\ The 2006 24-hour PM2.5 NAAQS, which is not the
subject of this action, is met when the 3-year average of the annual
98th percentile PM2.5 concentrations is 35 [mu]g/m\3\ or
less.
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To project future ozone and annual PM2.5 design values,
EPA relies on monitoring data from the Air Quality System (AQS)
combined with photochemical air quality modeling results. The Transport
Rule Proposal generates the projected future ozone values based on an
average of three design value periods which include the years 2003-2007
(i.e., design values for 2003-2005, 2004-2006, and 2005-2007). The
average of the three design values creates a ``5-year weighted
average'' value. The 5-year weighted average values were then projected
to the future years that were analyzed for the Transport Rule
Proposal.\14\ EPA used the 5-year weighted average concentrations to
project concentrations anticipated in 2012 to determine which
monitoring sites are expected to be nonattainment in this future year.
EPA also projected 2012 design values based on each of the three year
periods (i.e., 2003-2005, 2004-2006, and 2005-2007.) The highest
projection, referred to as ``maximum design value,'' gives an
indication of potential variability in future projections due to
differences in actual meteorology and emissions from what was modeled.
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\14\ See, Transport Rule Proposal, at 45246.
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EPA identified those sites that are projected to be attainment
based on the 5-year weighted average design value, but that have a
maximum design value (based on a single three year period) that exceeds
the NAAQS, as maintenance receptors. These sites are attaining the
NAAQS based on the projected average design values, but EPA anticipates
that there will be more difficulty in maintaining attainment of the
NAAQS at these locations if there are adverse variations in meteorology
or emissions. These projected maintenance sites are the ones that EPA
has used to determine if emissions from North Dakota sources
potentially interfere with maintenance of the 1997 8-hour ozone NAAQS
and 1997 annual PM2.5 NAAQS in other states in this action.
To evaluate ambient impacts from upwind states to maintenance
receptors, the Transport Rule Proposal uses a two step approach for
measuring each state's significant contribution. In the first step, EPA
evaluates through air quality modeling, contributions from individual
states to downwind maintenance receptors. States whose contributions to
any downwind receptors which are above the ``significant contribution''
threshold, one percent of the relevant NAAQS, are considered ``linked''
to those receptors for the purpose of the second step. In the second
step, EPA uses maximum cost thresholds, informed by air quality
considerations, to determine the portion of each state's contribution
that constitutes its ``interference with maintenance,'' or
``significant contribution.'' \15\
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\15\ For details, see: id., at 45233 et seq., and ``Air Quality
Modeling Technical Support Document,'' (AQMTSD) (June 2010),
available at Regulations.gov as Document ID No. EPA-HQ-OAR-2009-
0491-0047. For greater detail on air quality contributions see:
``Transport Rule Air Quality Contributions,'' Document ID No. EPA-
HQ-OAR-2009-0491-0060.
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EPA Transport Rule Proposal proposed a threshold for ``interference
with maintenance'' at one percent of the NAAQS for both
PM2.5 and ozone.\16\ For the 1997 annual PM2.5
EPA proposed in the Transport Rule Proposal a threshold of 0.15 [mu]g/
m\3\, without any further rounding up.\17\ States contributing less
than 0.15 [mu]g/m\3\ to downwind maintenance receptors are below the
threshold and as a result are excluded from further analysis. States
contributing 0.15 [mu]g/m\3\ or more are above the threshold and are
``linked'' to the counties in which the affected receptors are located.
States with ``linkages'' to downwind maintenance receptors are included
in the analytical process that determines the controls (if any)
required for compliance with the ``interference with maintenance''
element of section 110(a)(2)(D)(i) for the 1997 PM2.5
standards.
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\16\ Transport Rule Proposal, at 45237.
\17\ Note that, differently from CAIR, the Transport Rule
decouples the precision of air quality thresholds from the
monitoring reporting requirements and uses 2-digit values
representing one percent of the NAAQS. Id.
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For the 1997 8-hour ozone standard, EPA Transport Rule Proposal
proposed a threshold for ``interference with maintenance'' at 0.8 ppb,
one percent of the NAAQS. State contributions of 0.8 ppb and higher are
considered above the threshold, while state contributions less than 0.8
ppb are below the threshold and such states are excluded from further
analysis. States contributing significantly, 0.8 ppb or more, to
[[Page 56933]]
downwind maintenance receptors are considered to be ``linked'' to the
counties in which they are located and are included in the follow-up
process that determines the controls (if any) required of such states
to satisfy the ``interfere with maintenance'' element of section
110(a)(2)(D)(i) for the 1997 8-hour ozone standard.\18\
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\18\ Id.
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PM2.5
In the Transport Rule Proposal, EPA projected future concentrations
of PM2.5 to identify receptors that are expected to have
difficulty maintaining compliance with the NAAQS in 2012, referred to
as maintenance-only sites or maintenance receptors. For the 1997 annual
PM2.5 NAAQS, the Transport Rule Proposal identified 16
maintenance receptors in its modeling domain. The monitors at risk for
maintenance are located in seven states, including two in Illinois
(Cook County), four in West Virginia, six in Ohio, and one each in
Kentucky, New York, Pennsylvania and Texas.\19\ To determine the states
in the Eastern domain that contribute significantly to maintenance
receptors, the Transport Rule models the states' PM2.5
contribution to the maintenance receptors in these states. The largest
contribution from North Dakota emissions to the maintenance receptors
in these states was estimated to be 0.05 [mu]g/m\3\, a level two thirds
below the ``significant contribution'' threshold of 0.15 [mu]g/
m\3\.\20\ This small contribution excluded North Dakota from the
Transport Rule Proposal's follow-up analysis for the states that
contributed significantly and were ``linked'' to at least one of the
monitors at risk for maintenance of the NAAQS.\21\
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\19\ Table IV.C-8, id., at 45248.
\20\ Table IV.C-13, id., at 45255.
\21\ For ``linkages'' between states and maintenance-only sites
see Table IV.C-15, id., at 45259-60.
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To assist in the evaluation of whether emissions from a state's
sources interfere with maintenance of the NAAQS in western states, EPA
has developed, independent of the Transport Rule Proposal, a modeling
analysis identifying monitors at risk for maintenance of the NAAQS
within a modeling domain that includes the western states. The analysis
presented in the memo, ``Documentation of Future Year Ozone and Annual
PM2.5 Design Values for Western States'' (Western States
Design Values), uses model results from the Transport Rule Proposal
modeling Continental U.S. 36 km grid, which is coarser than the 12 km
grid used in the Transport Rule, but does not necessarily yield less
reliable results.\22\
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\22\ EPA's August 23, 2010 memo, ``Documentation of Future Year
Ozone and Annual PM2.5 Design Values for Western
States,'' at 5.
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EPA's modeling analysis of western states to identify monitors at
risk for maintenance of the 1997 annual PM2.5 NAAQS
identifies only two such maintenance-only receptors, in Los Angeles and
Orange Counties, California. These monitors are at least 1,100 miles
from North Dakota's closest area (the State's southwestern corner,)
\23\ and mountain ranges between North Dakota and the southern
California maintenance receptors, such as the Rocky Mountains, Wasatch
and the Sierra Nevada, present large obstacles to PM2.5
transport from North Dakota to the two maintenance receptors in Los
Angeles and Orange Counties. In addition, west of the Continental
Divide the prevailing winds generally move from south-westerly,
westerly, or north-westerly directions, as indicated by the typical
movement of weather systems. Thus, geography, topography and
meteorology of the region that encompasses North Dakota and California
make it unlikely for PM2.5 emissions and/or its precursors
to contribute significantly to California's maintenance receptors, and
thus interfere with maintenance of the annual PM2.5 1997
NAAQS at these receptors.
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\23\ This distance is estimated on a straight path from North
Dakota's southwestern corner to Los Angeles. Any emissions from
North Dakota sources reaching the Los Angeles and Orange Counties
would travel a longer distance because the sources would be farther
east and/or north than the State's southwestern corner, and because
long range transport air parcel pathways rarely follow a straight
path.
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It must also be noted that there are no maintenance receptors in
any of the western states adjacent, or relatively close, to North
Dakota, such as Montana, Idaho, Wyoming, and Utah. In fact, 2012
projected design values for the annual PM2.5 peaked in Utah,
Montana and Idaho at concentrations below 12 [mu]g/m\3\, and in Wyoming
at concentrations below 10 [mu]g/m\3\.\24\
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\24\ Western States Design Values (August 23, 2010) at 9-11.
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Turning to the 1997 24-hour PM2.5 NAAQS, in the
Transport Rule Proposal EPA did not evaluate nonattainment receptors
because there were no violations of these standards in portions of the
U.S. covered by the 12 km grid, which includes the 37 states east of
the Rockies.\25\ In fact, based on recent monitoring data (2007-2009
design values that are under final EPA review), the highest 24-hour
PM2.5 design value in 47 of the 48 states of the continental
U.S. (not including 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\.\26\ Therefore, outside of California, there are no areas
that we would expect to have difficulty in maintaining the 1997 24-hour
PM2.5 NAAQS. In California, the most recent (2009) 24-hour
PM2.5 design values show that the only monitors that might
be at risk for maintenance of the 1997 24-hour PM2.5 NAAQS
are in Turlock, Fresno, and Bakersfield, in the northern, central and
southern sections of the San Joaquin Valley.\27\ The high mountain
ranges on three sides of the Valley's boundaries (Coast Mountain with
5,000 feet peaks on the west, Sierra Nevada range with 14,000 feet
peaks on the east, and Tehachapi Mountains with 6,000 feet along the
southern boundary) are an obstacle to transport of PM2.5 and
its precursors into the valley. As noted earlier in our discussion of
the impacts from North Dakota emissions on annual PM2.5
concentrations, and in this case too, the geography (nearly 1,200 miles
distance), topography (high mountain ranges between North Dakota and
California), and meteorology (southwesterly or westerly directions of
prevailing winds) make it highly unlikely that emissions from North
Dakota contribute significantly to the San Joaquin Valley monitors at
risk for maintenance of the 24-hour PM2.5 NAAQS.
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\25\ EPA did not model projections for the 24-hour
PM2.5 NAAQS in the 36 km grid modeling domain. For the
states included in the Eastern domain see Table IV.C-13, Transport
Rule Proposal, at 45255.
\26\ Data undergoing review from EPA's Air Quality System, which
is EPA's repository of ambient air quality data. (See http://www.epa.gov/ttn/airs/airsaqs/).
\27\ The AQS preliminary design value data shows that in 2009
design values at monitors in these locations ranged from 60
[micro]g/m\3\ in Fresno and Turlock, to 70 [micro]g/m\3\ in
Bakersfield.
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In conclusion, our analysis indicates that emissions of
PM2.5 and/or its precursors from the sources in North Dakota
are unlikely to interfere with maintenance of the 24-hour and the
annual PM2.5 NAAQS by any other states.
8-Hour Ozone
In the Transport Rule Proposal, EPA projected future concentrations
of ozone to identify receptors, referred to as maintenance receptors,
that are expected to have difficulty maintaining compliance with the
1997 8-hour ozone NAAQS in 2012. To determine states that impact
maintenance-only sites, in the Transport Rule Proposal EPA models the
states' ozone contribution to these receptors. For the 8-hour ozone
NAAQS, EPA identified 16 maintenance
[[Page 56934]]
receptors in its modeling domain. The monitors at risk for maintenance
are located in a handful of states, including eight monitors in Texas,
four in Connecticut, two in Georgia, and one each in New York and
Pennsylvania.\28\ The largest contribution from North Dakota emissions
to the 16 maintenance receptors in these states was estimated to be 0.0
ppb, resulting in the exclusion of the State's emissions from further
analysis, and in the conclusion that North Dakota emissions do not
interfere with maintenance of the 1997 8-hour ozone NAAQS by any states
in the eastern U.S.A.
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\28\ Table IV.C-12, Transport Rule Proposal, at 45252-53
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As noted earlier, EPA has also developed a modeling analysis
identifying maintenance receptors within a modeling domain that
includes the western states.\29\ In the western states EPA identified
only four monitors at risk for maintenance of the 1997 8-hour ozone
NAAQS, and all four are in California, in Mercer, Placer, Riverside,
and Sacramento Counties. Geography and topography are not favorable to
ozone transport from North Dakota, which is approximately 1200 miles
northeast of the counties referenced above. In the absence of
significant northeasterly regional transport winds, mountain ranges
between North Dakota and the California maintenance receptors, such as
the Rocky Mountains, the Wasatch and the Sierra Nevada, present serious
obstacles to ozone transport from North Dakota to California. Thus,
geography and topography reduce the likelihood of transport from North
Dakota to California's maintenance receptors.
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\29\ Western States Design Values (August 23, 2010).
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Prevailing wind orientation in fact strongly supports the
conclusion that emissions from North Dakota sources are unlikely to
interfere with maintenance of the 1997 8-hour ozone standard in
California. West of the Continental Divide the prevailing winds
generally move from south-westerly, westerly, or north-westerly
directions, as indicated by the typical movement of weather systems. To
further evaluate the direction of regional transport winds affecting
the California maintenance receptors, EPA Region 8 has plotted back
trajectories starting at each maintenance receptor on high ozone days.
High ozone days include the top one third of the exceedance days (for
the 1997 8-hour ozone NAAQS) registered at each monitor in 2005 and
2006. As shown by the trajectories mapped for all four maintenance
receptors in Figure 3.1, Appendix A of EPA's supporting documentation,
on high ozone days air parcels converge on the Mercer, Placer,
Sacramento and Riverside monitors from the northwest, south and
southeast, but there are no pathways from the east/northeast directions
reaching even as far as the eastern Nevada border, let alone North
Dakota.
For a large number of receptors in western states, EPA's modeling
analysis could not calculate 2012 projected design values because these
receptors did not have at least 5 days with base year concentrations
equal to or greater than 70 ppb, as required by EPA's modeling
guidance. However, the observed maximum design values at these sites in
the 2003-2007 period were generally well below the 1997 ozone NAAQS.
The highest (non-California \30\) site had a maximum design value of 77
ppb. Additionally, the 2012 modeling results at western monitors (where
a future year design value could be estimated,) shows a downward trend
in ozone. There are no areas in the West where ozone is predicted to be
higher in 2012 (without CAIR) compared to 2005. On these bases it is
plausible to conclude that it is highly unlikely, but not impossible,
for these monitors to be at risk for maintenance of the 1997 8-hour
ozone NAAQS.
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\30\ We are excluding the California monitors from this portion
of our analysis because above we have already demonstrated that
North Dakota's emissions are unlikely to interfere with maintenance
at the modeled California maintenance monitors in the northern,
central and southern sections of the state. The factors we
considered--distance, topography, and wind orientation--apply
equally to the un-modeled monitors and make it plausible to conclude
that the same demonstration is true for North Dakota emissions'
impact on California non-modeled monitors.
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In conclusion, data and weight of evidence analysis presented in
this section support the position of the North Dakota Interstate
Transport SIP (adopted into the State SIP on April 1, 2009 and
submitted to EPA April 6, 2009) that emissions from North Dakota do not
interfere with maintenance of the 1997 8-hour ozone NAAQS by any other
state, consistent with the requirements of element (2) of CAA section
110(a)(2)(D)(i).
VI. Proposed Action
EPA is proposing partial approval of the addition to the North
Dakota SIP of the ``Interstate Transport of Air Pollution'' SIP
addressing the requirements of CAA section 110(a)(2)(D)(i) for the 1997
PM2.5 and 8-hour ozone National Ambient Air Quality
Standards (NAAQS). EPA is proposing approval of the language in Section
7.8.1, subsection B., ``Nonattainment and Maintenance Area Impact,''
that specifically addresses element (2) of section 110(a)(2)(D)(i), the
requirement that the SIP contain adequate provisions prohibiting
emissions from North Dakota from interfering with maintenance of the
1997 PM2.5 and 8-hour ozone NAAQS by any other state. The
language in Section 7.8.1, subsection B., that addresses element (1) of
section 110(a)(2)(D)(i) was approved by EPA in a June 3, 2010 Federal
Register action.
VII. Statutory and Executive Order Review
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 approves 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 2835, 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
[[Page 56935]]
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 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, Nitrogen dioxide, Ozone,
Particulate matter, Reporting and recordkeeping requirements, Volatile
Organic Compounds.
Authority: 42 U.S.C. 7401 et seq.
Dated: September 9, 2010.
Carol Rushin,
Acting Regional Administrator, Region 8.
[FR Doc. 2010-23292 Filed 9-16-10; 8:45 am]
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