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[Federal Register: September 17, 2010 (Volume 75, Number 180)]
[Proposed Rules]               
[Page 56928-56935]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr17se10-24]                         

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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: mastrangelo.domenico@epa.gov.
     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, 
mastrangelo.domenico@epa.gov.

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
---------------------------------------------------------------------------

    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).
---------------------------------------------------------------------------

    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.
---------------------------------------------------------------------------

    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]
BILLING CODE 6560-50-P
```