[Federal Register: June 11, 2010 (Volume 75, Number 112)]
[Rules and Regulations]
[Page 33174-33190]
[DOCID:fr11jn10-10]

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 52

[EPA-R06-OAR-2007-0993; FRL-9160-2]

Approval and Promulgation of Implementation Plans; New Mexico;
Interstate Transport of Pollution

AGENCY: Environmental Protection Agency (EPA).

ACTION: Final rule.

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SUMMARY: EPA is approving a portion of a State Implementation Plan
(SIP) submitted by the State of New Mexico for the purpose of
addressing the ``good neighbor'' provisions of the Clean Air Act (CAA)
section 110(a)(2)(D)(i) for the 1997 ozone National Ambient Air Quality
Standard (NAAQS) and the 1997 PM2.5 NAAQS. This SIP revision
satisfies a portion of the State of New Mexico's obligation to submit a
SIP that demonstrates that adequate provisions are in place to prohibit
air emissions from adversely affecting another state's air quality
through interstate transport. This rulemaking action is being taken
under section 110 of the CAA and addresses one element of CAA section
110(a)(2)(D)(i), which pertains to prohibiting air pollutant emissions
from within New Mexico from contributing significantly to nonattainment
of the 1997 8-hour ozone and PM2.5 NAAQS in any other state.

DATES: This final rule will be effective July 12, 2010.

ADDRESSES: EPA has established a docket for this action under Docket
Identification No. EPA-R06-OAR-2007-0993. All documents in the docket
are listed at www.regulations.gov. Although listed in the index, some
information is not publicly available, e.g., Confidential Business
Information or other information whose disclosure is restricted by
statute. Certain other material, such as copyrighted material, is not
placed on the Internet and will be publicly available only in hard copy
form. Publicly available docket materials are available either
electronically through www.regulations.gov or in hard copy at the Air
Planning Section (6PD-L), Environmental Protection Agency, 1445 Ross
Avenue, Suite 700, Dallas, Texas 75202-2733. The file will be made
available by appointment for public inspection in the Region 6 Freedom
of Information Act (FOIA) Review Room between the hours of 8:30 a.m.
and 4:30 p.m. weekdays except for legal holidays. Contact the person
listed in the FOR FURTHER INFORMATION CONTACT paragraph below or Mr.
Bill Deese at<PHONE_NUMBER> to make an appointment. If possible, please
make the appointment at least two working days in advance of your
visit. There will be a 15 cent per page fee for making photocopies of
documents. On the day of the visit, please check in at the EPA Region 6
reception area at 1445 Ross Avenue, Suite 700, Dallas, Texas.

FOR FURTHER INFORMATION CONTACT: Emad Shahin, Air Planning Section
(6PD-L), Environmental Protection

Agency, Region 6, 1445 Ross Avenue, Suite 700, Dallas, Texas 75202-
2733, telephone<PHONE_NUMBER>; fax number<PHONE_NUMBER>; e-mail
address<EMAIL_ADDRESS>
SUPPLEMENTARY INFORMATION: Throughout this document wherever ``we,''
``us,'' or ``our'' is used, we mean the EPA.

Outline

I. What action is EPA taking?
II. What is the background for this action?
III. What comments did EPA receive and how has EPA responded to
them?
IV. Final Action
V. Statutory and Executive Order Reviews

I. What action is EPA taking?

    We are approving a portion of the submission from the State of New
Mexico demonstrating that New Mexico has adequately addressed one of
the required elements of the CAA section 110(a)(2)(D)(i), the element
that prohibits air pollutant emissions from sources within a state from
contributing significantly to nonattainment of the relevant NAAQS in
any other state. We have determined that emissions from sources in New
Mexico do not significantly contribute to nonattainment of the 1997 8-
hour ozone NAAQS or the 1997 PM2.5 NAAQS in any other state.
Because emissions from sources in New Mexico do not significantly
contribute to nonattainment in any other state, section
110(a)(2)(D)(i)(I) does not require any substantive changes to New
Mexico's SIP.
    The remaining three elements of section 110(a)(2)(D) are that a
state's SIP contain adequate provisions to prevent: Interference with
maintenance of the NAAQS in any other state; interference with measures
required to prevent significant deterioration of air quality in any
other state; and interference with measures required to protect
visibility in any other state. EPA will evaluate the New Mexico SIP and
SIP submissions for compliance with these other requirements of section
110(a)(2)(D) for the 1997 8-hour ozone and 1997 PM2.5 NAAQS
in future rulemakings.

II. What is the background for this action?

    On July 18, 1997, EPA promulgated new standards for 8-hour ozone
and fine particulate matter (PM2.5). This action is being
taken in response to the July 18, 1997 revision to the 8-hour ozone
NAAQS and PM2.5 NAAQS. This action does not address the
requirements for the 2006 PM2.5 NAAQS or the 2008 8-hour
ozone NAAQS; those standards will be addressed in a later action.
    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) Submission to
Meet Current Outstanding Obligations Under Section 110(a)(2)(D)(i) for
the 8-Hour Ozone and PM2.5 National Ambient Air Quality
Standards'' (2006 Guidance) for SIP submissions that states should use
to address the requirements of section 110(a)(2)(D)(i). EPA developed
this guidance to make recommendations to states for making submissions
to meet the requirements of section 110(a)(2)(D) for the 1997 8-hour
ozone NAAQS and 1997 PM2.5 NAAQS.
    On September 17, 2007, EPA received a SIP submission from the State
of New Mexico to address the requirements of section 110(a)(2)(D)(i)
for both the 1997 8-hour ozone NAAQS and 1997 PM2.5 NAAQS.
The state based its submittal on EPA's 2006 Guidance. As explained in
the 2006 Guidance, the ``good neighbor'' provisions in section
110(a)(2)(D)(i) require each State to submit a SIP that contains
adequate provisions to prohibit emissions from sources within that
state from adversely affecting 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. In this
rulemaking EPA is addressing only the requirement that pertains to
preventing sources in the state from emitting pollutants in amounts
which will contribute significantly to nonattainment of the 1997 8-hour
ozone NAAQS and the 1997 PM2.5 NAAQS in any other state. In
its submission, the State of New Mexico indicated that its current SIP
is adequate to prevent such significant contribution to nonattainment
in any other state, and thus no additional emissions controls are
necessary at this time to alleviate interstate transport.
    On April 8, 2010, we published a direct final rule and a parallel
proposal to approve the portion of New Mexico's SIP submission that
addressed one element of the CAA section 110(a)(2)(D)(i), which
pertains to prohibiting air pollutant emissions from within New Mexico
from contributing significantly to nonattainment of the 1997 8-hour
ozone and 1997 PM2.5 NAAQS in any other state (75 FR 17868).
The direct final rule and proposal stated that if EPA received any
relevant adverse comments during the public comment period ending on
May 10, 2010, then EPA would withdraw the direct final rule and respond
to such comments in a subsequent final action based upon the proposal.
EPA received adverse comments during the comment period, and
accordingly EPA withdrew the direct final rule on May 3, 2010 (75 FR
23167). The April 8, 2010, proposal (75 FR 17894) provides the basis
for today's final action.

III. What comments did EPA receive and how has EPA responded to them?

    EPA received three comment letters on the April 8, 2010, direct
final rule and proposal. The letters can be found on the internet in
the electronic docket for this action. To access the letters, please go
to http://www.regulations.gov and search for Docket No. EPA-R06-OAR-
2007-0993, or contact the person listed in the FOR FURTHER INFORMATION
CONTACT paragraph above. The discussion below addresses those comments
and our response.

A. Comments From WildEarth Guardians

    Comment No. 1--The commenter argued that New Mexico and EPA did not
appropriately assess impacts to nonattainment in downwind states.
According to the commenter, New Mexico failed to assess the
significance of downwind impacts in accordance with EPA precedent and
refers to the 1998 NOX SIP Call.
    EPA Response--EPA disagrees with the commenter on this point.
Section 110(a)(2)(D) does not explicitly specify how states or EPA
should evaluate the existence of, or extent of, interstate transport
and whether interstate transport is of sufficient magnitude to
constitute ``significant contribution to nonattainment'' as a
regulatory matter. The statutory language is ambiguous on its face and
EPA must reasonably interpret that language when it applies it to
factual situations before the Agency.
    EPA agrees that the NOX SIP Call is one rulemaking in
which EPA evaluated the existence of, and extent of, interstate
transport. In that action, EPA developed an approach that allowed the
Agency to evaluate whether there was significant contribution to ozone
nonattainment across an entire region that was comprised of many
states. That approach included regional scale modeling and other
technical analyses that EPA deemed useful to evaluate the issue of
interstate transport on that geographic scale and for the facts and
circumstances at issue in that

rulemaking. EPA does not agree, however, that the approach of the
NOX SIP Call is the only way that states or EPA may evaluate
the existence of, and extent of, interstate transport in all
situations, and especially in situations where the state and EPA are
evaluating the question on a state by state basis, and in situations
where there is not evidence of widespread interstate transport.
    Indeed, EPA issued specific guidance with recommendations to states
about how to address section 110(a)(2)(D) in SIP submissions for the
1997 8-hour ozone NAAQS. EPA issued this guidance document, entitled
``Guidance for State Implementation Plan (SIP) Submissions to Meet
Current Outstanding Obligations Under Section 110(a)(2)(D)(i) for the
8-Hour Ozone and PM2.5 National Ambient Air Quality
Standards'' on August 15, 2006.\1\ This guidance document postdated the
NOX SIP Call, and was developed by EPA specifically to
address SIP submissions for the 1997 8-hour ozone NAAQS.
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    \1\ Memorandum from William T. Harnett entitled Guidance for
State Implementation Plan (SIP) Submissions to Meet Current
Outstanding Obligations Under Section 110(a)(2)(D)(i) for the 8-hour
Ozone and PM2.5 National Ambient Air Quality Standards
(Aug. 15, 2006) (``2006 Guidance''); p. 3.
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    Within the 2006 Guidance, EPA notes that it explicitly stated its
view that the ``precise nature and contents of such a submission [are]
not stipulated in the statute'' and that the contents of the SIP
submission ``may vary depending upon the facts and circumstances
related to the specific NAAQS.'' \2\ Moreover, within that guidance,
EPA expressed its view that ``the data and analytical tools available''
at the time of the SIP submission ``necessarily affect the content of
the required submission.'' \3\ To that end, EPA specifically
recommended that states located within the geographic region covered by
the Clean Air Interstate Rule (CAIR) \4\ comply with section
110(a)(2)(D) for the 1997 8-hour ozone NAAQS by complying with CAIR
itself. For states outside the CAIR rule region, however, EPA
recommended that states develop their SIP submissions for section
110(a)(2)(D) considering relevant information.
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    \2\ Id. at 3.
    \3\ Id.
    \4\ In this action the expression ``CAIR'' refers to the final
rule published in the May 12, 2005 Federal Register and entitled
``Rule to Reduce Interstate Transport of Fine Particulate Matter and
Ozone (Clean Air Interstate Rule); Revisions to Acid Rain Program;
Revisions to NOX SIP Call; Final Rule'' (70 FR 25162).
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    EPA explicitly recommended that relevant information for section
110(a)(2)(D) submissions addressing significant contribution to
nonattainment ``might include, but is not limited to, information
concerning emissions in the State, meteorological conditions in the
State, the distance to the nearest nonattainment area in another State,
reliance on modeling conducted by EPA in determining that such State
should not be included within the ambit of the CAIR, or such other
information as the State considers probative on the issue of
significant contribution.'' \5\ In addition, EPA recommended that
states might elect to evaluate significant contribution to
nonattainment using relevant considerations comparable to those used by
EPA in CAIR, including evaluating impacts as of an appropriate year
(such as 2010) and in light of the cost of control to mitigate
emissions that resulted in interstate transport.
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    \5\ Id. at 5.
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    The commenter did not acknowledge or discuss EPA's actual guidance
for section 110(a)(2)(D) SIP submissions for the 1997 8-hour ozone
NAAQS, and thus it is unclear whether the commenter was aware of it. In
any event, EPA believes that the New Mexico submission and EPA's
evaluation of it is consistent with EPA's guidance for the 1997 8-hour
ozone NAAQS. For example, as discussed in the direct final notice, the
State of New Mexico and EPA considered information such as monitoring
data in other states, geographical and meteorological information, and
technical studies of the nature and sources of nonattainment problems
in various downwind states. These are among the types of information
that EPA recommended and that EPA considers relevant. Thus, EPA has
concluded that the State's submission, and EPA's evaluation of that
submission, meet the requirements of section 110(a)(2)(D) and are
consistent with applicable guidance.
    Finally, EPA notes that the considerations the Agency recommended
to states in the 2006 Guidance are consistent with the concepts of the
NOX SIP Call referenced by the commenter: (a) The overall
nature of the ozone problem; (b) the extent of downwind nonattainment
problems to which upwind state's emissions are linked; (c) the ambient
impact of the emissions from upwind States' sources on the downwind
nonattainment problems; and (d) the availability of high cost-effective
control measures for upwind emissions. The only distinction in the case
of the New Mexico submission at issue here would be that because the
available evidence indicates that there is so very little contribution
of emissions from New Mexico sources to nonattainment in other states,
it is not necessary to advance to the final step and evaluate whether
the cost of controls for those sources is above or below a certain cost
of control as part of determining whether the contribution constitutes
``significant contribution to nonattainment'' for regulatory purposes,
as was necessary in the NOX SIP Call and in CAIR.
    Comment No. 2--The commenter believes that New Mexico and EPA did
not appropriately assess impacts to nonattainment in downwind states in
terms of air quality. Specifically, the commenter objected to EPA's
proposed approval because New Mexico assessed impacts in downwind
states by considering only areas that had monitoring data as for
evaluating significant contribution to nonattainment. In other words,
the commenter is concerned that New Mexico did not assess impacts in
areas that have no monitor. The commenter implied that this reliance on
monitor data is inconsistent with both section 110(a)(2)(D) and with
EPA's guidance, by which the commenter evidently means the
NOX SIP Call. In support of this assertion, the commenter
quoted from the NOX SIP Call proposal in which EPA addressed
the proper interpretation of the statutory phrase ``contribute
significantly to nonattainment:''

    ``The EPA proposes to interpret this term to refer to air
quality and not to be limited to currently designated nonattainment
areas. Section 110(a)(2)(D) does not refer to `nonattainment areas,'
which is a phrase that EPA interprets to refer to areas that are
designated nonattainment under section 107 (section
107(d)(1)(A)(I))''

According to the commenter, this statement, and similar ones in the
context of the final NOX SIP Call rulemaking, establish that
states and EPA cannot utilize monitoring data to evaluate the existence
of, and extent of, interstate transport. Furthermore, the commenter
interprets the reference to ``air quality'' in these statements to
support its contention, amplified in later comments, that EPA must
evaluate significant contribution in areas in which there is no
monitored nonattainment.
    EPA response--EPA disagrees with the commenter's arguments. First,
the commenter misunderstands the point that EPA was making in the
quoted statement from the NOX SIP Call proposal (and that
EPA has subsequently made in the context of

CAIR). When EPA stated that it would evaluate impacts on air quality in
downwind states, independent of the current formal ``designation'' of
such downwind states, it was not referring to air quality in the
absence of monitor data. EPA's point was that it was inappropriate to
wait for either initial designations of nonattainment for a new NAAQS
under section 107(d)(1), or for a redesignation to nonattainment for an
existing NAAQS under section 107(d)(3), before EPA could assess whether
there is significant contribution to nonattainment of a NAAQS in
another state.
    For example, in the case of initial designations, section 107(d)
contemplates a process and timeline for initial designations that could
well extend for two or three years following the promulgation of a new
or revised NAAQS. By contrast, section 110(a)(1) requires states to
make SIP submissions that address section 110(a)(2)(D) and interstate
transport ``within 3 years or such shorter period as the Administrator
may prescribe'' of EPA's promulgation of a new or revised NAAQS. This
schedule does not support a reading of section 110(a)(2)(D) that is
dependent upon formal designations having occurred first. This is a key
reason why EPA determined that it was appropriate to evaluate
interstate transport based upon monitor data, not designation status,
in the CAIR rulemaking.
    The commenter's misunderstanding of EPA's statement concerning
designation status evidently caused the commenter to believe that EPA's
assessment of interstate transport in the NOX SIP Call was
not limited to evaluation of downwind areas with monitors. This is
simply incorrect. In both the NOX SIP Call and CAIR, EPA
evaluated significant contribution to nonattainment as measured or
predicted at monitors. For example, in the technical analysis for the
NOX SIP Call, EPA specifically evaluated the impacts of
emissions from upwind states on monitors located in downwind states.
The NOX SIP Call did not evaluate impacts at points without
monitors, nor did the CAIR rulemaking. EPA believes that this approach
to evaluating significant contribution is correct under section
110(a)(2)(D), and EPA's general approach to this threshold
determination has not been disturbed by the courts.\6\
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    \6\ Michigan v. U.S. EPA, 213 F.3d 663, 674-681 (DC Cir. 2000);
North Carolina v. EPA, 531 F.3d 896, 913-916 (DC Cir. 2008)
(upholding EPA approach to determining threshold despite remanding
other aspects of CAIR).
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    Finally, EPA disagrees with the commenter's argument that the
assessment of significant contribution to downwind nonattainment must
include evaluation of impacts on non-monitored areas. Neither section
110(a)(2)(D)(i)(I) provisions, nor the 2006 Guidance EPA issued for the
1997 8-hour ozone NAAQS, support the commenter's position, as neither
refers to any explicit mandatory or recommended approach to assess air
quality in non-monitored areas.\7\ The same focus on monitor data as a
means of assessing interstate transport is found in the NOX
SIP Call and in CAIR. An initial step in both the NOX SIP
Call and CAIR was the identification of areas with current monitored
violations of the ozone and/or PM2.5 NAAQS.\8\ The
subsequent modeling analyses for NAAQS violations in future years (2007
for the SIP Call and 2010 for CAIR) likewise evaluated future
violations at monitors in areas identified in the initial step. Thus,
the commenter is simply in error that EPA has not previously evaluated
the presence and extent of interstate transport under section
110(a)(2)(D) by focusing on monitoring data. Indeed, such monitoring
data was at the core of both of these efforts. In neither of these
rulemakings did EPA evaluate significant contribution to nonattainment
in areas in which there was no monitor. This is reasonable and
appropriate, because data from a properly placed federal reference
method monitor is the way in which EPA ascertains that there is a
violation of the 1997 8-hour ozone NAAQS or of the 1997
PM2.5 NAAQS in a particular area.
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    \7\ 2006 Guidance, p. 5.
    \8\ ``Based on this approach, we predicted that in the absence
of additional control measures, 47 counties with air quality
monitors [emphasis ours] would violate the 8-hour ozone NAAQS in
2010 * * *.'' From the CAIR proposed rule of January 30, 2004 (69 FR
4566, 4581). The NOX SIP call proposed rule action reads:
``* * * For current nonattainment areas, EPA used air quality data
for the period 1993 through 1995 to determine which counties are
violating the 1-hour and/or 8-hour NAAQS. These are the most recent
3 years of fully quality assured data which were available in time
for this assessment.'' See, 62 FR 60336.
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    EPA did not use photochemical modeling to determine if an area is
violating the 1997 8-hour ozone or 1997 PM2.5 NAAQS to
designate the area as nonattainment without supporting monitoring data.
EPA's regulations for these NAAQS, the monitoring requirements for
these NAAQS, and EPA's guidance for designations for these NAAQS
provide for such designations for violating areas to be based only on
monitoring data. In addition, this is reasonable for these particular
NAAQS because photochemical models, while based on the best science
available, only provide a best estimate of air quality. EPA's 2007
modeling guidance \9\ recognizes that model results and projections
will continue to have uncertainty.
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    \9\ EPA-454/B-07-002, April 2007, ``Guidance on the Use of
Models and other Analyses for Demonstrating Attainment of Air
Quality Goals for Ozone, PM2.5 and Regional Haze'',
Office of Air Quality Planning and Standards, Air Modeling Group.
Research Triangle Park, North Carolina, available at http://
www.epa.gov/scram001/guidance/guide/final-03-pm-rh-guidance.pdf.
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    Therefore, even if modeling analyses indicated violation of the
1997 8-hour ozone NAAQS in other states, EPA would not make a
determination that these areas should be designated nonattainment for
these NAAQS without monitoring data in the area to support a
determination of nonattainment. In summary, in order for there to be
significant contribution to nonattainment for either of these specific
NAAQS, there must be a monitor with data showing a violation of that
NAAQS. EPA has concluded that by considering data from monitored areas,
its assessment of whether emissions from New Mexico contribute
significantly to ozone nonattainment in downwind states is consistent
with the 2006 Guidance, and with the approach used by both the CAIR
rule and the NOX SIP Call, and EPA modeling guidance.
    Comment No. 3--In support of its comments that EPA should assess
significant contribution to nonattainment in nonmonitored areas, the
commenter argued that existing modeling performed by another
organization ``indicates that large areas of neighboring states will be
likely to violate the ozone NAAQS.'' According to the commenter, these
likely ``violations'' of the ozone NAAQS were predicted for the year
2018, as reflected in a slide from a July 30, 2008 presentation before
the Western Regional Air Partnership (``Review of Ozone Performance in
WRAP Modeling and Relevant to Future Regional Ozone Planning'').\10\ In
short, the commenter argues that modeling performed by the WRAP
establishes that there will be violations of the 1997 8-hour ozone
NAAQS in 2018 in non-monitored areas of states adjacent to New Mexico.
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    \10\ The presentation is available for review as Document ID
 EPA-R06-OAR-2007-0993-0008.9 at Regulations.gov, Docket ID
 EPA-R06-OAR-2007-0993.
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    EPA Response--EPA disagrees with this comment on several grounds.
First, EPA does not agree that it is appropriate when satisfying the
requirements of Section 110(a)(2)(D) to evaluate significant
contribution to nonattainment for the 1997 8-hour ozone NAAQS by
modeling ambient

levels in areas where there is no monitor to provide data to establish
a violation of the NAAQS in question. Section 110(a)(2)(D) does not
require such an approach, EPA has not taken this approach in the
NOX SIP Call or other rulemakings under section
110(a)(2)(D), and EPA's prior analytical approach has not been
disturbed by the courts.
    Second, the commenter's own description of the ozone concentrations
predicted for the year 2018 as projecting ``violations'' of the ozone
NAAQS is inaccurate. Within the same sentence, quoted above, slide 28
is described as displaying the projected fourth maximum ozone reading
for the year 2018, and as indicating that ``* * * air quality * * *
will exceed or violate [emphasis ours] the 1997 ozone NAAQS.'' By
definition, a one year value of the fourth maximum above the NAAQS only
constitutes an exceedance of the NAAQS; to constitute a violation of
the 1997 8-hour ozone NAAQS, the average of the fourth high for three
consecutive years at the same monitor must exceed the standard. Thus,
even if the WRAP presentation submitted by the commenter were
technically sound, the conclusion drawn from it by the commenter is
inaccurate and does not support its claim of projected violations of
the NAAQS in large areas (monitored or unmonitored) of New Mexico's
neighboring states.
    Even if EPA believed that it was appropriate to use modeling to
establish violations of the 1997 8-hour ozone NAAQS, EPA has reviewed
the WRAP presentation submitted by the commenter, and believes that
there was a substantial error in the WRAP modeling software that led to
overestimation of ground level ozone concentrations. A recent study
conducted by Environ for the Four Corners Air Quality Task Force
(FCAQTF) \11\ has demonstrated that excessive vertical transport in the
CMAQ and CAMx models over high terrain was responsible for
overestimated ground level ozone concentrations due to downward
transport of stratospheric ozone.\12\ Environ has developed revised
vertical velocity algorithms in a new version of CAMx that eliminated
the excessive downward transport of ozone from the top layers of the
model. This revised version of the model is now being used in a number
of applications throughout high terrain areas in the West. In
conclusion, EPA believes that this key inadequacy of the WRAP model,
noted above, makes it inappropriate support for the commenter's
concerns about large areas of other states violating the 1997 8-hour
ozone NAAQS projected for 2018 in areas without monitors.
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    \11\ This document is available for review at the
regulations.gov Web site under Docket ID No. EPA-R06-OAR-2007-0993.
    \12\ Stoeckenius, T.E., C.A. Emery, T.P. Shah, J.R. Johnson,
L.K. Parker, A.K. Pollack, 2009. ``Air Quality Modeling Study for
the Four Corners Region,'' pp. ES-3, ES-4, 3-4, 3-12, 3-30, 5-1.
Prepared for the New Mexico Environment Department, Air Quality
Bureau, Santa Fe, NM, by ENVIRON International Corporation, Novato,
CA.
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    Comment No. 4--As additional support for its assertion that EPA
should require modeling to assess ambient levels in unmonitored
portions of other states, the commenter relied on an additional study
entitled the ``2009 Uinta Basin Air Quality Study'' (UBAQS). The
commenter argued that the UBAQS further supports its concern that New
Mexico and EPA, having limited the evaluation of downwind impacts only
to areas with monitors, failed to assess ozone nonattainment in non-
monitored areas. According to the commenter, UBAQS modeling \13\
results show that: (a) the Wasatch Front region is currently exceeding
and will exceed in 2012 the 1997 8-hour ozone NAAQS; and (b) based on
2005 meteorological data, portions of the four counties in the
southwestern corner of Utah are also currently in nonattainment and
will be in nonattainment in 2012.\14\
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    \13\ In this action the expression ``UBAQS'' refers to the
``FINAL REPORT UBAQS TECHNICAL REPORT'', June 30, 2009. The
presentation is available for review as Document ID  EPA-
R06-OAR-2007-0993-0008.9 at regulations.gov, Docket ID
EPA-R06-OAR-2007-0993.
    \14\ UBAQS. The southwestern area referred to by the commenter
includes portions of Washington, Iron, Kane, and Garfield Counties.
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    EPA Response--As noted above, EPA does not agree that it is
appropriate to assess significant contribution to nonattainment for the
1997 8-hour ozone NAAQS in the way advocated by the commenter. In
particular, EPA does not agree that it is necessary to evaluate
significant contribution to areas where only the model predicts
nonattainment where there are no monitors. Even if EPA felt it was
appropriate to use model results to determine areas that are not
attaining the standard, EPA does not agree that the modeled
nonattainment of the 1997 8-hour ozone NAAQS (current and projected) in
the Wasatch Front Range area in the UBAQS supports the commenter's
concerns about the need to evaluate the possibility of significant
contribution from New Mexico to nonattainment in these areas. Based on
what the commenter presented, EPA sees several problems with the
commenter's interpretation of the UBAQS analysis results for counties
in Utah's southwestern corner: ``based on 2005 meteorological data,
portions of Washington, Iron, Kane, and Garfield Counties are also in
nonattainment and will be in nonattainment in 2012.'' \15\ First, the
commenter's interpretation of the predicted ozone concentrations shown
in Figures 4-3a and 4-3b (pages 4 and 5 of the comment letter) is
inaccurate. A close review of the legend in these figures indicates
that the highest ozone concentrations predicted by the model for
portions of the counties noted above are somewhere between 81.00 and
85.99 ppb, but the exact modeled value is not specified and there are
only three grid cells with this value range estimated. If the actual
model prediction is less than or equal to 84.94 ppb then the area is
attaining the 1997 8-hour ozone NAAQS, if it is predicted as greater
than 84.94 ppb then the modeling is indicating that it is not attaining
those NAAQS. Thus, the current and predicted design values for the
three grid cells in southwestern Utah area identified in Figures 4-3a
and 4-3b could both be in attainment, or both in nonattainment, or one
of them in attainment and the other in nonattainment, for the 1997 8-
hour ozone NAAQS. EPA does not believe that this evidence adequately
establishes that one or both areas definitely violate the NAAQS, even
if the information were taken at face value.
---------------------------------------------------------------------------

    \15\ WG's April 16, 2010 comment letter, pp. 3. The letter is
available for review at the regulations.gov Web site Docket ID No.
EPA-R06-OAR-2007-0993.
    Page three of the commenter's letter.
---------------------------------------------------------------------------

    Second, even if the design values predicted for these unmonitored
areas were at the top of the 81.00-85.99 ppb range, their reliability
would remain questionable. The UBAQS itself identifies and illustrates
major shortcomings of its modeling analysis, only to neglect assessing
the impact of these shortcomings on the modeling results.\16\ The study
deviates in at least two significant ways from EPA's 2007 guidance on
SIP modeling.\17\ One deviation is the UBAQS modeling reliance on fewer
than the five years of data recommended by EPA to generate an 8-hour
ozone current design value (DVC). UBAQS relaxed this requirement so
that sites with as little as 1 year of data were included as DVCs in
the analysis. The other deviation is in the computation of the relative
responsive

factor (RRF), which directly affects the modeling's future design value
(DVF).\18\ Due to unavailability of data satisfying EPA's
recommendation that the RRF be based on a minimum of five days of ozone
concentrations above 85 ppb, UBAQS modeling uses RRFs based on one or
more days of ozone concentrations above 70 ppb.\19\ Also, looking at
Figures 3-19a-j of the UBAQS report, which cover ozone modeling
performance through September of 2005, shows the modeling to have an
over prediction bias for ozone. So, EPA concludes that the modeling
analysis results provided by the commenter are unreliable for
projecting nonattainment status even if EPA believed it was appropriate
to use modeling for this purpose for the 1997 8-hr ozone NAAQS.
---------------------------------------------------------------------------

    \16\ See UBAQS, pp. 4-27 to 4-29.
    \17\ EPA, Guidance on the Use of Models and other Analyses for
Demonstrating Attainment of Air Quality Goals for Ozone,
PM2.5 and Regional Haze. Office of Air Quality Planning
and Standards, Air Modeling Group. Research Triangle Park, North
Carolina (2007), available at http://www.epa.gov/scram001/guidance/
guide/final-03-pm-rh-guidance.pdf.
    \18\ Id., DVC x RRF = DVF.
    \19\ See UBAQS, p. 4-28.
---------------------------------------------------------------------------

    Finally, even if it were appropriate to consider modeled violations
and the modeling were reliable for this purpose, the commenter has not
raised any convincing evidence that emissions from New Mexico sources
are impacting southwestern Utah during the predicted high ozone events.
Specifically, no assessment or source apportionment was performed that
indicated sources in New Mexico contributed to the three grid cells
with modeled high values that may be modeled nonattainment values in
Utah. In fact, the predominant wind direction would not carry emissions
from New Mexico into southwestern Utah. Furthermore, in evaluating the
Figures provided (Fig 4-3a to 4-4b) and other information in the
modeling report, the modeling also does not indicate that emissions
from New Mexico are impacting the higher modeled ozone values in the
southwestern Utah area.
    In summary, EPA does not agree that it is appropriate for purposes
of section 110(a)(2)(D) to use modeled nonattainment as a basis for
evaluation, for these two NAAQS (1997 8-hour ozone NAAQS and PM 2.5
NAAQS) especially in light of the concerns with the modeling discussed
above. Even if EPA were to use modeling for this purpose, the UBAQS
modeling analyses does not clearly predict violations of the 1997 8-
hour ozone NAAQS in western Colorado and eastern Utah. In particular,
the UBAQS modeling does not clearly establish violations of the NAAQS
in southwestern Utah because of the way the results were reported.
Significantly, the model does project violations in the Salt Lake City
area (in 2006 and 2012 model years), but monitors in the area do not
substantiate these modeled predictions. Based on monitoring data for
2007-2009, the Salt Lake City area does not have a monitored design
value within 6 ppb of the level of the 1997 8-hour ozone NAAQS. In
addition, EPA does not consider the UBAQS modeling reliable because the
modeling deviates from EPA guidance and appears to have an over-
prediction bias. Finally, the commenter did not provide evidence that
emissions from New Mexico in fact contributed significantly to the
modeled exceedances or violations projected in this modeling.
    Comment No. 5--In support of its arguments that EPA should not
assess significant contribution to nonattainment through evaluation of
impacts at monitors instead of modeling impacts where there is no such
monitor, the commenter cited a past statement by EPA to the effect that
the ozone monitoring network in the western United States needs to be
expanded. The quoted statements included EPA's observation that:
``[v]irtually all States east of the Mississippi River have at least
two to four non-urban O3 monitors, while many large mid-
western and western States have one or no non-urban monitors.'' 74 FR
34525 (July 16, 2009). From this statement, the commenter argues that
it is not appropriate for EPA to limit evaluation of significant
contribution to nonattainment of the ozone NAAQS in other states to
reliance on monitoring data instead of modeled ambient levels.
    EPA Response--EPA does not disagree that there are relatively few
ozone monitors in the western states, and that relatively few of these
ozone monitors are currently located in non-urban areas of western
states. However, the commenter failed to note that the quoted statement
from EPA concerning the adequacy of western monitors came from the
Agency's July 16, 2009, proposed rulemaking entitled ``Ambient Ozone
Monitoring Regulations: Revisions to Network Design Requirements.''
This statement was thus taken out of context, because EPA was in that
proposal referring to changes in state monitoring networks that it
anticipates will be necessary in order to implement not the 1997 8-hour
ozone NAAQS, the subject of this rulemaking, but rather the next
iteration of the ozone NAAQS. Because the new ozone standard is likely
to be significantly more stringent than the 1997 8-hour ozone NAAQS, it
is anticipated there will be a need to evaluate ambient levels in
previously unmonitored areas of the western United States. The fact
that additional monitors may be necessary in the future for a newer
ozone NAAQS does not mean that the existing ozone monitoring networks
are insufficient for the 1997 8-hour ozone NAAQS, as the commenter
implies. Indeed, states submit annual monitor network reports to EPA
and EPA evaluates these to insure that the deployment of monitors in
the state meets the applicable regulatory requirements and guidance
recommendations.
    For example, New Mexico itself submits just such a report on an
annual basis, and EPA reviews it for adequacy.\20\ All states submit
comparable reports. Absent a specific concern that another state's
current monitor network is inadequate to evaluate ambient levels of the
1997 8-hour ozone NAAQS, EPA has no reason to believe that the
evaluation of possible significant contribution from New Mexico sources
in reliance on those monitors is incorrect.
---------------------------------------------------------------------------

    \20\ See the New Mexico Annual Monitoring Network Plan dated
July 14, 2009. The plan is available for review at the
regulations.gov Web site under Docket ID No.  EPA-R06-OAR-
2007-0993.
---------------------------------------------------------------------------

    Comment No. 6--The commenter objected to EPA's proposed approval of
the New Mexico's SIP submission because neither New Mexico nor EPA
performed a specific modeling analysis to assure that emissions from
New Mexico sources do not significantly contribute to nonattainment of
the 1997 8-hour ozone NAAQS in downwind States.
    EPA Response--First, this comment is incorrect. EPA and New Mexico
did provide modeling as part of the evaluation of whether emissions
from sources in New Mexico impact monitors with violating data in other
states. The modeling is discussed in the proposed federal register and
technical support document for this action and is one of the primary
considerations in EPA's approval. The modeling that the commenter
claims is necessary but absent, is modeling to assess impacts in areas
with no monitors. As explained above, EPA believes that the assessment
of significant contribution to nonattainment under section 110(a)(2)(D)
for these NAAQS should be based upon impacts at monitors.
    Second, EPA disagrees with the commenter's belief that only
modeling can establish whether or not there is significant contribution
from one state to another. As noted above, EPA does not believe that
section 110(a)(2)(D) requires modeling. While modeling can be useful,
EPA believes that other forms of analysis can be sufficient to evaluate
whether or not there is significant contribution to nonattainment. For
this reason, EPA's 2006 Guidance

recommended other forms of information that states might wish to
evaluate as a qualitative approach as part of their section
110(a)(2)(D) submissions for the 1997 8-hour ozone NAAQS. EPA has
concluded that the qualitative approach used by New Mexico in addition
to modeling to assess the existence of, and extent of, any significant
contribution to downwind ozone nonattainment is consistent with EPA's
2006 Guidance.
    Comment No. 7--In further support of its argument that EPA must use
modeling to evaluate whether there is significant contribution to
nonattainment under section 110(a)(2)(D), the commenter noted that EPA
itself asks other agencies to perform such modeling in other contexts.
As examples, the commenter cited four examples in which EPA commented
on actions by other agencies in which EPA recommended the use of
modeling analysis to assess ozone impacts prior to authorizing oil and
gas development projects. As supporting material, the comment includes
quotations from and references to EPA letters to Federal Agencies on
assessing impacts of oil and gas development projects.\21\ The
commenter questioned why EPA's recommendation for such an approach in
its comments to other Federal Agencies, did not result in its use of
the same approach to evaluate the impacts from New Mexico's emissions
and to insure compliance with Section 110(a)(2)(D)(i)(I). The commenter
reasoned that the emissions that would result from the actions at issue
in the other agency decisions, such as selected oil and gas drilling
projects, would be of less magnitude and importance than the statewide
emissions at issue in an evaluation under section 110(a)(2)(D).
---------------------------------------------------------------------------

    \21\ WG's April 16, 2010 comment letter, pp. 8-9. Complete
versions of the EPA comment letters referenced here were attached to
the comment as Exhibits 3 through 6, and are viewable on the
Regulations.gov Web site as Documents ID No. EPA-R06-OAR-2007-0993-
0008.3 through 0993-0008.6.
---------------------------------------------------------------------------

    EPA Response--As explained above, this comment is misplaced because
EPA and New Mexico did employ modeling as part of the evaluation.
Further, EPA disagrees with the commenter's fundamental argument that
modeling is mandatory in all instances in order to evaluate significant
contribution to nonattainment, whether by section 110(a)(2)(D), by EPA
guidance, or by past EPA precedent. EPA's applicable guidance made
recommendations as to different approaches that could lead to
demonstration of the satisfaction of the interstate transport
requirements for significant contribution to nonattainment in other
states. EPA explicitly recommended that relevant information for
section 110(a)(2)(D) submissions addressing significant contribution to
nonattainment ``might include, but is not limited to, information
concerning emissions in the State, meteorological conditions in the
State, the distance to the nearest nonattainment area in another State,
reliance on modeling conducted by EPA in determining that such State
should not be included within the ambit of the CAIR, or such other
information as the State considers probative on the issue of
significant contribution.'' Even EPA's own CAIR analysis relied on a
combination of qualitative and quantitative analyses. EPA's CAIR
analysis excluded certain western states on the basis of a qualitative
assessment of topography, geography, and meteorology.\22\
---------------------------------------------------------------------------

    \22\ See 69 FR 4581, January 30, 2004.
---------------------------------------------------------------------------

    Furthermore, EPA believes that the commenter's references to EPA
statements commenting on the actions of other agencies are inapposite.
As the commenter is aware, those comments were made in the context of
the evaluation of the impacts of various federal actions pursuant to
National Environmental Policy Act, not the Clean Air Act. As explained
above, in the context of section 110(a)(2)(D), EPA does not agree that
only modeling is always required to make that different type of
evaluation, and EPA itself has relied on other more qualitative
evidence when it deemed that evidence sufficient to reach a reasoned
determination.
    Comment No. 8--In further support of its argument that EPA should
require a specific type of modeling to evaluate significant
contribution to nonattainment, the commenter referred to EPA
regulations governing nonattainment SIPs. The commenter noted 40 CFR
51.112(a)(1), which states that: ``[t]he adequacy of a control strategy
shall be demonstrated by means of applicable air quality models, data
bases, and other requirements specified in appendix W of [Part 51]
(Guideline on Air Quality Models).'' The commenter argues that this
regulation appears to support the commenter's position that modeling is
required to satisfy the significant contribution element of
110(a)(2)(D).
    EPA Response--EPA disagrees with this comment. The cited language
implies that the need for control strategy requirements has already
been demonstrated, and sets a modeling analysis requirement to
demonstrate the adequacy of the control strategy developed to achieve
the reductions necessary to prevent an area's air quality from
continuing to violate the NAAQS. EPA's determination that emissions
from sources in New Mexico do not contribute significantly to
nonattainment for the 1997 8-hour ozone NAAQS in any other state
eliminates the need for a control strategy aimed at satisfying the
section 110(a)(2)(D) requirements. Moreover, EPA interprets the
language at 40 CFR 51.112(a): ``[e]ach plan must demonstrate that the
measures, rules, and regulations contained in it are adequate to
provide for the timely attainment and maintenance of the national
standard that it implements,'' to refer to modeling for attainment
demonstrations, an integral part of nonattainment area SIPs under part
D of the CAA. This interpretation was upheld by the Sixth Circuit Court
of Appeals. Wall v. U.S. EPA, 265 F.3d 426, 436 (6th Cir. 2001). This
modeling may also be appropriate under certain circumstances for
maintenance SIPs under section 110(a)(1). Thus, the commenter's cited
regulation is not relevant to EPA's technical demonstration assessing
whether emissions from New Mexico contribute significantly to
nonattainment in any other states under section 110(a)(2)(D)(i).
    Comment No. 9--The commenter expressed concern with EPA statements
in the proposed approval about the current factual attainment of the
Denver Metro/North Front Range area of Colorado. The commenter noted
that nine counties in the Denver area are currently formally designated
``nonattainment'' for the 1997 8-hour ozone NAAQS. The commenter took
issue with EPA's description of the nature of the nonattainment problem
in this area as resulting from an unusually bad ozone season that
``temporarily'' resulted in violations of the NAAQS. The commenter
argued that data from the 2001-2003 period and the 2005-2007 period
showed consistent violations of the 1997 8-hour ozone NAAQS in the
Denver area, and that these violations are the reason for the current
nonattainment designation.
    EPA Response--EPA disagrees that formal designation status of an
area is the most important consideration in evaluating the existence
of, and extent of, the impacts of interstate transport from one state
to another. In past actions under section 110(a)(2)(D), EPA has
interpreted that provision to turn upon the actual monitored ambient
levels in a downwind area, regardless of the formal designation status
of the area. For example, EPA developed the CAIR

rule based upon evaluation of monitor data showing violations of the
1997 PM2.5 NAAQS in certain areas, in advance of completing
the designation process for those NAAQS under section 107(d). \23\ EPA
agrees that the designation status of an area is a relevant
consideration, but the actual monitored ambient levels are an
appropriate measure, especially when there is evidence that the
monitored levels are different than reflected by the designation for
the area. EPA itself has also looked to future attainment status as a
means of evaluating the presence of, and extents of, interstate
transport. This analysis depends not upon the anticipated formal
designation status of the area, but rather upon the anticipated
monitored level of the area.\24\
---------------------------------------------------------------------------

    \23\ See: Final CAIR rule, 70 FR 25,162, 25,263-25,269.
    \24\ EPA notes that the commenter itself also made the argument
that nonattainment for purposes of section 110(a)(2)(D) should be
viewed ``in terms of air quality, and not in terms of area
designations'' on page 2 of its own comment letter.
---------------------------------------------------------------------------

    EPA believes that the commenter is placing undue importance upon
the EPA's characterization of the data from Denver area monitors as
``temporarily'' in nonattainment based on the ``bad'' ozone season of
2007. EPA agrees that this area has historically had relatively high
ambient levels. However, as explained in the proposal, these levels
have improved, and more importantly, have improved during the period
that is most relevant and most recent. As noted in the proposal, recent
monitoring data from the Denver area for the 2007-2009 period indicates
that the area is below the level of the NAAQS. For this trend to
change, EPA anticipates that the Denver area would have to have
dramatically higher ozone levels in 2010 than the area has experienced
for many years. EPA believes that it is more reasonable to conclude
that the monitored attainment of this area at the time of the analysis
done by New Mexico will continue. Therefore there could not be
significant contribution from sources in New Mexico to nonattainment in
Denver.
    EPA believes that the downward trend in monitored nonattainment in
the Denver area supports this conclusion. At the time the modeling was
performed to support the state's section 110(a)(2)(D) submission,
Denver was monitoring attainment (the 2004-2006 8-Hour Ozone Design
Value (DV) was 81 ppb).\25\ In 2007, the Denver area experienced a
particularly bad ozone season, and inclusion of the data from this year
did temporarily affect the monitored values in this area. However, the
most recent data for this area, preliminary data for 2007-2009 DV
(awaiting final data validation), is 82 ppb even with inclusion of the
very high ozone values from 2007. Thus, the area's most recent DV based
upon preliminary data is several ppb below the 1997 8-hour ozone NAAQS,
and the area is therefore currently monitoring attainment.
---------------------------------------------------------------------------

    \25\ Data from EPA's Air Quality System which is EPA's
repository of ambient air quality data. (http://www.epa.gov/ttn/
airs/airsaqs/).
---------------------------------------------------------------------------

    The downward trend in ozone concentrations is in part the result of
a sustained effort to attain the NAAQS in the Denver area. The Denver
area has seen a drop in ozone levels in the last 10 years attributable
in part to federal measures that have reduced mobile source emissions.
In addition, Colorado adopted an Ozone Action Plan in December 2008
that included additional reductions in emissions of ozone precursors
(NOX and VOCs), that will further aid the area in
maintaining attainment. Given these facts, EPA concludes that the
monitored attainment of the 1997 8-hour ozone NAAQS in the Denver area
is likely to continue.
    Comment No. 10--The commenter also disputed the EPA statement in
the proposal that it is ``unlikely that Denver will be in nonattainment
at the end of the 2010 ozone season,'' and questioned why EPA did not
cite or include any actual model data to support this assertion. The
commenter specifically took issue with EPA's reference to the ``2010
ozone season'' in the proposal because section 110(a)(2)(D) would
prohibit significant contribution to nonattainment at all times, not
simply during the ``2010 ozone season.''
    EPA Response--As discussed above, EPA believes the monitoring data
adequately demonstrates that the Denver area is attaining the standard
and is likely to continue to do so. The commenter is correct that EPA
did not cite modeling that showed that Denver would be in attainment in
2010 in the proposal. We are aware, however, of the photochemical
modeling for Denver completed as part of the ``Ozone Action Plan''
adopted by Colorado in December 2008.\26\ This plan included the
benefits of federal measures and fleet turnover and additional local
NOX and VOC reductions. The plan also included photochemical
modeling that indicated all monitors in the area would be in attainment
of the 1997 8-hour ozone NAAQS in 2010. The modeling results supplement
the monitoring results discussed previously indicating the area is in
attainment and will be in attainment in 2010.
---------------------------------------------------------------------------

    \26\ ``Denver Metro Area & North Front Range Ozone Action Plan
Including Revisions to the State Implementation Plan'', Approved by
Colorado Air Quality Control Commission, December 12, 2008.
---------------------------------------------------------------------------

    Further, EPA believes that the commenter is mistakenly assuming
that EPA's reference to the ``2010 ozone season'' implied that section
110(a)(2)(D) would not require the elimination of emissions from
sources in an upwind state that significantly contributed to violations
of a NAAQS at any time of the year. In the case of the 1997 8-hour
ozone NAAQS, however, it is a fact that there is an ``ozone season'' in
many places across the county. Higher ozone concentration levels
typically occur during the warmer, sunnier portions of the year,
especially the summer. Like most areas, Denver has an ozone season.
Therefore, it is not unreasonable for EPA to evaluate the likely
impacts of data from monitors in this area during the ``ozone season.''
    EPA also disagrees that an evaluation focused on impacts on 2010
levels is not adequate for purposes of section 110(a)(2)(D). As further
discussed elsewhere in this notice, EPA's 2006 Guidance to states for
section 110(a)(2)(D) SIP submissions recommended that states might
elect to evaluate the existence of, and extent of, significant
contribution to nonattainment in other states by evaluating impacts as
of an appropriate year (such as 2010) and in light of the cost of
control to mitigate emissions that resulted in interstate transport.
EPA itself in the context of the CAIR rule evaluated whether there
would be such impacts in 2010. This year was a reasonable choice,
because it correlated with the presumptive attainment dates for states
with nonattainment areas. For example, in the case of the 1997
PM2.5 NAAQS, the applicable attainment date is as
expeditiously as practicable, but not later than five years from the
effective date of the designation, i.e., by 2010. Because 2010 is a
reasonable date for this analysis, given the purpose of section
110(a)(2)(D), and is consistent with EPA's recommendations in the 2006
Guidance, EPA concludes that the selection of this date for the
analysis supporting the New Mexico submission was appropriate. The
commenter did not suggest another date that would be more appropriate
nor did they explain the basis for requiring a different year for this
analysis.
    Comment No. 11--The commenter also asserted that EPA was wrong in
stating that the Denver area had not experienced a 4th highest 8-hour
ozone reading of 92 ppb in the last 15 years. The commenter claimed
that the Denver metro area experienced a 4th highest

max of 95 ppb at the Roxborough Park monitor in Douglas County in 2005
and of 95 ppb at the Applewood monitor in Jefferson County in 1998 and
in 2003.
    EPA Response--In response to this comment, EPA rechecked the data
in the EPA's Air Quality System (AQS) and believes the commenter was in
error that a fourth highest maximum of 95 ppb occurred at the
Roxborough Park (also know as the Chatfield monitor) monitor in 2005.
EPA's AQS indicates a value of 84 ppb in 2005. However, EPA's AQS does
indicate that a 95 ppb 4th high occurred in 2003 at the Roxborough Park
monitor and this may be the date that the commenter intended. In any
event, upon closer examination, EPA concludes that the commenter is
correct that values above 92 ppb have occurred in the Denver area in
the last 15 years.
    EPA also notes that the current DVs (2007-2009) for these two
monitors (Roxborough Park and Applewood) are 77 ppb and 76 ppb, which
is well below the 1997 8-hour ozone NAAQS. Furthermore, these monitors
would have to have fourth high daily maximum 8-hour monitored values of
104 and 111 ppb respectively in 2010 to have a 2008-2010 DV violating
the 1997 8-hour ozone NAAQS. The fourth high daily maximum value
monitored the last 15 years in the Denver area was 95 ppb which is
significantly lower than the 104 or 111 ppb values that would have to
be monitored for either of these two monitors to be violating the 1997
8-hour ozone NAAQS.
    Therefore, EPA believes that the commenter's correction that there
have been higher values (maximum of 95 ppb in the last 15 years) at
monitors in the Denver area does not fundamentally affect EPA's
evaluation in this case. The higher values were not at the monitor that
was the basis for the Denver area design value in the last several
years. The monitor that has been the basis for the Denver area DV has
been the Rocky Flats North monitor. Even though the commenter is
correct that the area has monitored higher values at certain monitors
in the past, these monitors are not the monitors that have in recent
years determined whether the area will continue to monitor attainment
because they have not recorded the highest design value in the area.
The Rocky Flats North monitor has the highest 2007-2009 Denver area DV
of 82 ppb and is based upon fourth high values of 90 ppb in 2007, 79
ppb in 2008, and 79 ppb in 2009. This monitor would have to have a
fourth high daily maximum of 97 ppb in 2010 to result in a violation of
the 1997 8-hour ozone NAAQS. Therefore, it does not change EPA's
conclusion that the Denver area continues to monitor attainment and
therefore emissions from sources in New Mexico cannot be contributing
significantly to violations of the 1997 8-hour ozone NAAQS in this
area.
    Comment No. 12--The commenter also pointed to modeling data used by
New Mexico that appears to contradict the conclusion that emissions
from New Mexico do not contribute significantly to violations of the
1997 8-hour ozone NAAQS in Denver. The commenter argued that data
available in New Mexico's own technical support document that was part
of EPA's record (Docket No. EPA-R06-OAR-2007-0993) establish that
emissions from New Mexico sources ``often contributes greater than 2
parts per billion in ozone on days when exceedances of the 1997 ozone
NAAQS are recorded in Denver'' and can contribute ``more than 5% to
Denver's total ozone concentrations.'' Finally, the commenter argued
that New Mexico wrongly assumed that this amount of contribution was
not relevant ``under the assumption that the region was not in
nonattainment'' when the area is currently designated nonattainment.
    EPA Response--EPA disagrees with the commenter's conclusions drawn
from the modeling. The modeling was conducted using an emissions
inventory from 2002. Because emissions in the year 2010 are expected to
be lower, EPA considers this modeling to be a conservative estimate of
ozone levels in the future and of the impact of New Mexico's emissions
on other states. EPA believes that the modeling shows higher impacts
than are actually occurring. The modeling utilized existing CENRAP
modeling databases available at the time and the source apportionment
evaluation was conducted using the 2002 emission inventory databases.
Because the available databases were for 2002 and not 2010, EPA
considers the results of the modeling conservative because significant
emission reductions are expected to occur throughout the modeled area
between 2002 and 2010 (as a result of both federal and state measures,
including fleet turnover impacts) that would result in lower ambient
ozone levels and fewer exceedances of the 1997 8-hour ozone NAAQS
throughout the modeling domain.
    Specifically, there are three elements in this analysis that EPA
concludes lead to overestimation of the impacts of New Mexico sources
and therefore make this modeling less reliable to determine that
sources in New Mexico contribute significantly to violations of the
1997 8-hour NAAQS in Colorado (or any other state). These three
elements that result from using a 2002 and not a 2010 emission
inventory are: (a) Additional emissions reductions in other states as a
result of ozone nonattainment SIPs have been implemented that were not
reflected in the 2002 emission inventory; \27\ (b) additional emissions
reductions as a result of federal measures (including On-road, Non-
road, and the impacts of fleet turnover) throughout the modeling domain
since 2002; and (c) additional reductions from large stationary
NOX sources and from mobile sources as a result of federal
measures that have occurred in New Mexico since 2002. As a result of
these differences in the emission inventory between 2002 and 2010, New
Mexico's Technical Support Document describing and evaluating the
modeling indicated that the impacts for New Mexico's emissions were
considered conservative estimates and were expected to overstate the
State's contribution to areas in other states. EPA believes that these
conservative assumptions make the modeling reliable for purposes of
determining that there is not a significant contribution from sources
in New Mexico to the other states, but less reliable for purposes of
determining that there is such significant contribution. EPA believes
that the modeling relied upon by the State is conservative because of
the three emission elements discussed above and that this is further
supported by studies referred to by the commenter. Other studies
support the conclusion that the Denver area will be monitoring
attainment in 2010 for the 1997 8-hour ozone NAAQS, and therefore
emissions from sources in New Mexico would not be contributing
significantly to nonattainment in this area. Specifically, the WRAP
model emission inventories for 2002 and 2018 showed decreases
nationally in ozone precursors (NOX and VOC.) \28\ The UBAQS
modeling report included emission inventory assessments between 2006
and 2012 that also showed decreases in New Mexico's NOX
emissions for the part of New Mexico

that was in the 12 km modeling grid.\29\ Finally, the fact that Denver
is monitoring attainment at this time is further indication that the
2002 modeling was conservative because it predicted exceedances in
Denver, while the 2010 monitoring data is showing attainment.
---------------------------------------------------------------------------

    \27\ Additional emission reductions have occurred as a result of
1-hour ozone and 8-hour ozone nonattainment area SIPs for Denver and
other areas in the modeling domain (Dallas, Houston, etc.). The most
recent SIP submitted indicated that all of the Denver area monitors
would be in attainment in 2010 with the 1997 8-hour ozone NAAQS. The
Denver SIP also included an analysis of emission inventories in the
Denver area that showed a net decrease in NOX and VOC
emissions between 2006 and 2010 (Ibid DOAP) despite the inclusion of
growth in Oil and Gas emissions in the Denver area. (DOAP)
    \28\ WRAP EDMS, http://vista.cira.colostate.edu/TSS/EDMS.aspx.
    \29\ ``UINTA BASIN AIR QUALITY STUDY (UBAQS)'', prepared by
Environ for the Independent Petroleum Association of Mountain States
(IPAMS), June 30, 2009. Tables 2-18 and 2-20. The UBAQS 12 km grid
included parts of northwestern New Mexico (including parts of the
San Juan basin) and the emission inventory data indicated that
emissions of NOX from this area were going to decrease
from 115,942 tpy in 2006 to 95,867 tpy in 2012.
---------------------------------------------------------------------------

    Because the modeling was conservative and overstates the extent of
contribution from sources in New Mexico to the Denver area, it is
inappropriate to use the modeling as a definitive determination of New
Mexico's impacts on downwind areas. The modeling was designed to be
conservative and as such only provides a clear indication of non impact
on downwind nonattainment areas. Therefore, EPA disagrees that the
modeling supports the conclusion of significant contribution from New
Mexico sources to the Denver nonattainment area as the commenter
indicated. The commenter is correct that the CENRAP based modeling with
a 2002 emission inventory showed impacts that were above 2 ppb and
contribution levels that were above 5%, but due to the conservative
nature of the 2002 assessment, EPA does not conclude that it indicates
that sources in New Mexico have a significant contribution to
nonattainment in Denver.
    EPA also believes that NOX emissions in upwind states
are the most relevant consideration for interstate transport of ozone.
In the final CAIR rule, EPA concluded that NOX emissions
were the primary pollutant to reduce in order to yield reductions in
interstate transport of emissions that affect levels of ozone in the
context of the 1997 8-hour ozone NAAQS.\30\ Recent photochemical
modeling in the New Mexico and Colorado region further support this
conclusion, and therefore we have thus focused on NOX
emissions in the context of ozone in this action as well.
---------------------------------------------------------------------------

    \30\ See: Final CAIR rule, 70 FR 25162, 25174 (``As discussed in
section III below, for 8-hour ozone, we reiterate the finding of the
NOX SIP Call that NOX emissions, and not VOC
emissions, are of primary importance for interstate transport
purposes.'')
---------------------------------------------------------------------------

    As reflected in the New Mexico submission and the UBAQS modeling
documentation, New Mexico has decreased emissions of NOX
from several sources which would lessen New Mexico's impact on ozone in
areas outside of New Mexico. Therefore, the reductions in
NOX emissions in New Mexico would decrease the impacts from
New Mexico on Denver's ambient ozone levels when transport conditions
would occur that New Mexico's emissions could impact the Denver area. A
review of the UBAQS report indicates New Mexico's NOX
reductions are mostly from elevated point source reductions (i.e., from
tall stationary source stacks). Elevated emissions would have the
greatest chance to transport downwind, so these reductions are likely
among the most effective at reducing long range transport impacts on
ozone levels regionally. In any event, based on preliminary 2007-2009
data, Denver is attaining the 1997 8-hour ozone NAAQS. Therefore, New
Mexico's emissions cannot be considered as contributing significantly
to nonattainment of those NAAQS in the Denver area
    In summary, the Denver area is monitoring attainment of the 1997 8-
hour ozone NAAQS. The modeling submitted by the State to support its
submission indicating impacts from sources in New Mexico on the Denver
area is conservative, and probably overestimates both the ozone levels
in Denver and any impacts from New Mexico's emissions. There have been
significant emission reductions in the modeled area, supporting the
conclusion that the modeling based on 2002 represents a conservative
description of ozone levels and New Mexico's impact on the Denver area
and therefore should not be relied upon solely to draw a conclusion
about the impact of emissions from New Mexico in the Denver area.
Considering the modeling in conjunction with the expected emission
reductions and the actual monitoring data in this area, EPA concludes
that emissions from New Mexico are not contributing to nonattainment of
the 1997 8-hour ozone NAAQS in the Denver area.
    Comment No. 13--The commenter argued that New Mexico and EPA
inappropriately relied on analyses conducted in connection with CAIR to
justify its conclusion that emissions from sources in New Mexico do not
contribute significantly to nonattainment in downwind states with
regards to the 1997 PM2.5 NAAQS. According to the commenter,
neither of the modeling analyses EPA used during the development of the
CAIR rule supports the conclusion.
    The commenter acknowledged that the REMSAD modeling that EPA used
initially for CAIR in 2004 assessed emissions from New Mexico, but
claimed that EPA eventually ``rejected'' this modeling and replaced it
with analysis using the CMAQ model as a more ``accurate'' means of
assessing PM2.5 impacts among states. The commenter did note
that EPA explained in the final CAIR rule that it believed the REMSAD
model ``treats the key physical and chemical processes associated with
secondary aerosol formation and transport,'' but pointed to EPA`s
statement that the REMSAD model ``does not have all the scientific
refinements of CMAQ'' and also to EPA's use of the CMAQ modeling for
the final CAIR rule instead of the REMSAD modeling. The commenter thus
implied that the REMSAD modeling could have no relevance to whether
emissions from New Mexico sources contribute significantly to
nonattainment in other states for purposes of the 1997 PM2.5
NAAQS.
    Similarly, the commenter argued that the CMAQ modeling could not
support the conclusion that New Mexico sources are not contributing
significantly to violations of the NAAQS in other states. The commenter
claimed that although New Mexico was included in the CMAQ
PM2.5 modeling domain for CAIR, EPA did not specifically
assess impacts from New Mexico to downwind States. The commenter
acknowledged that EPA conducted state by state ``zero out'' modeling
for 37 states, but claimed that because EPA had not conducted such a
zero out modeling run for New Mexico, the CMAQ model runs do not
support the proposed conclusion in this action.
    EPA Response--EPA disagrees with the commenter's judgment that the
technical analyses conducted in conjunction with CAIR do not provide
technical support for the conclusion that New Mexico sources do not
contribute significantly to violations of the 1997 PM2.5
NAAQS in any other state. EPA agrees that it progressively refined its
analytical approach from the time of the proposed CAIR rule to the
final CAIR rule, but it does not follow that the analyses done for CAIR
are inappropriate for consideration in today's action. EPA believes
that the analyses conducted for CAIR in fact provide technical support
to the conclusion that emissions from New Mexico sources do not
contribute significantly to violations of these PM2.5 NAAQS
in any other state.
    EPA conducted modeling in the CAIR proposal using REMSAD modeling.
With respect to the REMSAD modeling, the commenter is correct that EPA
specifically evaluated the impact of emissions from New Mexico on other
states in the eastern half of the United

States. The modeling indicated a 0.03 [mu]g/m\3\ maximum impact from
New Mexico's emissions on downwind PM2.5 nonattainment areas
in 2010, which was significantly lower than the 0.15 [mu]g/
m3 value used as the threshold for significance in the
proposed CAIR rule and the 0.20 [mu]g/m3 value used in the
final CAIR rule.\31\ In other words, EPA's analysis indicated that the
impact of emissions from New Mexico sources were only a small fraction
of the initial threshold amount that EPA considered relevant as the
first stage of the analysis to determine the existence of, and extent
of, impact on other states.
---------------------------------------------------------------------------

    \31\ See, Final CAIR rule 70 FR 25162, at 25174.
---------------------------------------------------------------------------

    The commenter implied that EPA's subsequent use of the CMAQ model
for the final CAIR rule per se renders REMSAD invalid for purposes of
today's action. To support this assertion, the commenter overstated the
potential limitations of the REMSAD model, a misimpression heightened
by the way in which the commenter described EPA's own stated position.
The full statement by EPA in the final CAIR rule was: \32\
---------------------------------------------------------------------------

    \32\ See, Final CAIR rule 70 FR 25162, at 25234.

    ``However, even though REMSAD does not have all the scientific
refinements of CMAQ, we believe that REMSAD treats the key physical
and chemical processes associated with secondary aerosol formation
and transport. Thus, we believe that the conclusions based on the
---------------------------------------------------------------------------
proposal modeling using REMSAD are valid * * *''

This was not a categorical dismissal of REMSAD modeling for all
purposes; it was a recognition that REMSAD was reliable for certain
purposes even though the subsequent CMAQ modeling was an improvement.
During rulemaking, it is appropriate for EPA to make improvements and
refinements to models and the associated databases. EPA responded to
comments raising concerns about reliance on the REMSAD modeling results
from the proposal package and determined that decisions and
determinations based on the proposal REMSAD modeling were still valid
in the final CAIR rule.
    With respect to the CMAQ modeling, New Mexico was not among the 37
states for which it did specific ``zero out'' modeling runs. EPA
disagrees, however, with the commenter's extrapolation that this means
EPA ``did not assess'' the impacts of emissions from New Mexico with
respect to the 1997 PM2.5 NAAQS in the final CAIR rule. To
the contrary, EPA's evaluation of New Mexico with REMSAD was part of
the analysis for the proposed CAIR rule and EPA did not reject the
results of the REMSAD modeling in the final CAIR rule.\33\ The lack of
significant impact on nonattainment from New Mexico and other Western
States shown by the REMSAD modeling in the proposal helped influence
the more refined modeling analysis in the CAIR final rule which focused
only on the Eastern States.
---------------------------------------------------------------------------

    \33\ In this action, ``CAIR Proposal'' refers to the proposal
rule published on January 30, 2004 in the Federal Register and
entitled ``Rule to Reduce Interstate Transport of Fine Particulate
Matter and Ozone'', Interstate Air Quality Rule, 69 FR 4566.
---------------------------------------------------------------------------

    In considering this comment, EPA has looked again at the use of the
REMSAD modeling for the CAIR proposal for assessing New Mexico's
impacts on other States. We continue to believe that the REMSAD results
are sufficient to make a determination of no significant contribution
to nonattainment of the 1997 PM2.5 NAAQS in other states
because of the very small impacts that were estimated from emissions
from New Mexico sources. The REMSAD modeling had indicated that New
Mexico's impacts on downwind 2010 PM2.5 nonattainment areas
was only 15% of the significance level used in the final CAIR rule.
Because the REMSAD modeling indicated values of only 15% of the final
significance level, EPA did not consider the differences between the
two modeling platforms (REMSAD and CMAQ) to be significant enough to
lead to further analysis using CMAQ based modeling. EPA has determined
in this action that the results from the REMSAD based modeling continue
to support the conclusion that emissions from New Mexico sources are
not contributing significantly to violations of the 1997
PM2.5 NAAQS in other states. The commenter did not
articulate any way in which the distinctions between REMSAD and CMAQ
would result in at least a seven-fold increase in the estimated impacts
of emissions from New Mexico emissions on another state's 1997
PM2.5 nonattainment area. EPA does not believe that such a
divergence would be likely.
    Comment No. 14--The commenter argued that it is also inappropriate
for EPA to rely on the CAIR modeling because the 2004 REMSAD model did
not include other western states (including Arizona, California,
Nevada, Utah, Idaho, Oregon, and Washington). The commenter asserted
that EPA never assessed the impacts of emissions from New Mexico to
these western states in the CAIR modeling and that this is problematic
because there are PM2.5 nonattainment areas in California
and in Utah. Although not clear, the commenter apparently argues that
the existence of designated PM2.5 nonattainment areas in
California and Utah renders the CAIR modeling irrelevant. More
specifically, the commenter argues that because EPA has recently
designated certain counties in the Salt Lake City area and Cache
County, Utah as nonattainment for the 2006 PM2.5 NAAQS, EPA
was obligated to assess and limit downwind impacts accordingly in
accordance with Section 110(l) of the Clean Air Act.
    EPA Response--EPA disagrees with the commenter on this issue.
First, this rulemaking addresses the potential impacts of emissions
from New Mexico sources on other states with violations of the 1997
PM2.5 NAAQS, not the 2006 PM2.5 NAAQS. Therefore,
EPA's assessment of New Mexico's SIP was based on potential impacts on
areas violating the 1997 PM2.5 NAAQS (15 [mu]g/m\3\ annual
and 65 [mu]g/m\3\ 24-hour standard). The application of section
110(a)(2)(D) to the 2006 PM2.5 NAAQS, or other NAAQS, will
be addressed in later actions that pertain to those NAAQS.
    Second, EPA believes that the analysis conducted in conjunction
with CAIR is both relevant and very probative in evaluating the
presence of, and extent of, interstate transport from New Mexico
sources to other states in this action. The CAIR modeling and analysis
specifically evaluated impacts on areas that were violating the 1997
PM2.5 NAAQS. The other western states identified by the
commenter were in the CAIR modeling domain but were not evaluated
further in the CAIR rule because, with the exception of California and
Montana, these states were in attainment of the 1997 PM2.5
NAAQS.\34\ Absent areas with violations of those NAAQS, there could be
no significant contribution to violations of the 1997 PM2.5
NAAQS. With regard to California and Montana, EPA indicated in the CAIR
rule that interstate transport impacts were not a significant
contributor to these areas, therefore impacts from New Mexico sources
to California were not likely.\35\
---------------------------------------------------------------------------

    \34\ See, Final CAIR rule 70 FR 25162, at 25169: (``Only two
States in the western part of the U.S., California and Montana, have
counties that exceeded the PM2.5 standards'') and
(``Because interstate transport is not believed to be a significant
contributor to exceedances of the PM2.5 standards in
California or Montana, today's final CAIR does not cover these
States'').
    \35\ Id.
---------------------------------------------------------------------------

    Finally, even aside from the CAIR analysis, EPA does not believe
that emissions from New Mexico sources contribute significantly to
violations of the 1997 PM2.5 NAAQS in California. The areas
of California with violations of the 1997 PM2.5 NAAQS are
generally

located far to the west, hundreds of miles from New Mexico sources,
across large expanses of mountain ranges that would impede transport,
and generally upwind from New Mexico. EPA believes that the predominant
meteorological conditions would carry New Mexico emissions to the east,
north, or south but not generally to the west. As a result, EPA
concludes that it is very unlikely that New Mexico's emissions
transport hundreds of miles to the west to the 1997 PM2.5
NAAQS in California.\36\ The CAIR modeling only addressed areas that
were expected to be in nonattainment in 2010, based on existing
monitoring data at the time and 2010 photochemical modeling. Other than
California, none of the other states mentioned by the commenter were
monitoring nonattainment, or designated nonattainment for the 1997
PM2.5 standards, at the time these analyses were conducted.
---------------------------------------------------------------------------

    \36\ EPA reached this same conclusion in the CAIR rule. See,
Final CAIR rule 70 FR 25162, at 25169.
---------------------------------------------------------------------------

    Although not cited by the commenter, EPA notes that there has been
one monitored violation of the 1997 PM2.5 annual NAAQS in
Utah. It occurred in 2002-2004 time period at a single monitor in the
Salt Lake City area. This violation has not continued. In this
instance, the state concluded that the monitor was heavily impacted by
a nearby source. After the state instituted controls at the source, the
design value has dropped to less than 45 [mu]g/m\3\ in the last four
years. EPA notes that the impact of a nearby source does not in and of
itself negate the possibility of impacts of interstate transport at
that monitor as well. However, because that monitor has not
subsequently shown any violation of the 1997 PM2.5 NAAQS,
EPA concludes that there are no areas in Utah with violations of that
NAAQS to which New Mexico sources could be contributing significantly.
All other PM2.5 monitors in the area have consistently had
DVs below 55 [mu]g/m\3\ since the 2001-2003 DV period.
    Comment No. 15--The commenter also criticized modeling that the
state and EPA relied upon because of concerns about the accuracy of the
underlying emissions inventories on which the models relied. In
particular, the commenter claimed that the modeling fails to address
recent growth in emission inventories for oil and gas operations in New
Mexico that have been raising the emissions from the state higher than
have been previously reported in emissions inventories.
    The commenter argued that these increases in emissions at least
call into question the accuracy of the modeling relied upon by EPA to
support the proposed approval of the State's submission, and at worst
demonstrate that EPA has failed to address a key aspect of contribution
to nonattainment in downwind states from New Mexico sources.
    The commenter listed several recent reports that estimated
increased emissions of SO2, NOX, and VOCs that
result from the growth of oil and gas exploration in certain areas in
New Mexico. The more recent studies cited by the commenter were:
     The November 25, 2009 inventory of 2006 oil and gas
emissions in the San Juan Basin of New Mexico, which includes San Juan,
Rio Arriba, McKinley, and Sandoval Counties, prepared by the
Independent Petroleum Association of the Mountain States (``IPAMS'').
This inventory found that oil and gas point and area sources within
this region annually released 42,075 tons of NOX, 60,697
tons of volatile organic compounds (``VOCs'') and 305 tons of sulfur
dioxide (``SO2'').;
     The August 2009 report on 2005 emissions in the Four
Corners region of northwestern New Mexico, which found that oil and gas
point and area sources within the region annually released 57,682 tons
of NOX, 668 tons of SO2, and 117,370 tons of
VOCs. The report indicates that by 2018, these emissions will increase
to 65,543 tons of NOX, 670 tons of SO2, and
143,050 tons of VOCs; and
     The 2007 WRAP Phase II Inventory of 2002 oil and gas
emissions, which found that oil and gas activities throughout New
Mexico released 112,540 tons of NOX and 13,925 tons of
SO2, and that by 2018 would release 110,034 tons of
NOX and 13,002 tons of SO2 in the State.
    The commenter argued that without specifically addressing these
more recent increases in the emissions associated with oil and gas
development, New Mexico and EPA have no basis to conclude that the
modeling relied upon in the proposed approval is accurate or ensures
that emissions are not and will not significantly contribute to
nonattainment in other states. The commenter also noted that the
modeling prepared for CAIR utilized emission inventories from 2001,
which would likewise fail to account for the more recent increase in
emissions associated with oil and gas development.
    EPA Response--EPA shares the commenter's concern with emissions
from oil and gas development, and agrees that dramatic increases in
such emissions, and especially emissions from sources that are not
appropriately controlled, have the potential to contribute
significantly to violations of NAAQS in other states. However, EPA has
investigated this issue in response to the commenter's concerns in this
action, and has concluded that the information currently available does
not indicate that New Mexico's emissions from oil and gas development
are significantly contributing to violations of the 1997 8-hour ozone
NAAQS and 1997 PM2.5 NAAQS in other states. To reach this
conclusion, EPA has used available information and extrapolated what
the impacts of the additional emissions from oil and gas development
would be in a worst case scenario, as part of evaluating how those
increases would affect the modeling results and other information EPA
relied upon in the proposal.
    EPA has to make regulatory decisions using the emissions
inventories and analyses that are available at the time of the
decision. These inventories are, of course, constantly being updated
and refined. The CAIR modeling used a base year emission inventory from
2001 that EPA then projected to 2010, which was the timeframe that EPA
used for the analysis of New Mexico's impacts on areas in other states
with monitors projected to have violations of the 1997 PM2.5
NAAQS. The CENRAP modeling used a 2002 inventory to assess New Mexico's
ozone impacts on areas in other states with monitors projected to have
violations of the 1997 8-hour ozone NAAQS. At the time this modeling
was conducted, EPA believed that the emission estimates for oil and gas
development were appropriate.
    The commenter cited studies that have been conducted more recently
to refine estimates of current emissions and future projected emission
levels from oil and gas development in areas of New Mexico. These more
recent studies indicate that emissions from oil and gas development are
likely much higher than those assumed in the models. Because the
studies do not indicate the amount of emissions growth that has
happened since the 2001/2002 timeframe, however, it is difficult to
determine the impact this presumed increase would have. Therefore, to
evaluate this concern, below we consider a worst case estimate impact
of oil and gas emissions on whether emissions from sources in New
Mexico significantly contribute to nonattainment in other states.
    The reports cited by the commenter indicate that emissions from all
oil and gas development in New Mexico in the years from 2002-2006 have
a range of up to 112,540 tpy of NOX, 117,370 tpy of VOC, and
13,925 tpy of SO2. In

comparison, the modeling conducted using the 2002 CENRAP emission
inventory databases included emissions from all sources in New Mexico
with totals of 306,194 tpy of NOX, 1,749,081 tpy of VOC and
100,174 tpy of SO2.\37\ The modeling conducted for CAIR
included an inventory from all sources of 242,782 tpy of NOX
and 173,724 tpy of SO2 for the 2010 base level emissions for
sources in New Mexico.\38\ These emissions inventories used for the
CENRAP modeling and the CAIR modeling did include some emissions from
oil and gas development activities in New Mexico, so EPA believes that
some portion of emissions attributed to such sources in the more recent
studies were included in statewide emission inventories from all
sources and thus in the CENRAP and CAIR modeling.
---------------------------------------------------------------------------

    \37\ WRAP EDMS, CENRAP TSD.
    \38\ CAIR Proposal TSD.
---------------------------------------------------------------------------

    It would be very difficult to ascertain the exact amount of
emissions from oil and gas sources that were included in the emission
inventories for these two modeling evaluations and thus to ascertain
the exact amount that the inventories used for the modeling exercises
underestimate such emissions. Therefore, to evaluate how much the
additional emissions from oil and gas development could impact the
determination, we have used a worst case estimate of how much higher
the emissions in New Mexico could be, based on the studies provided by
the commenter. If one uses the highest NOX value from these
reports of 112, 540 tpy and compare that with the 306,194 tpy of
NOX (from the CENRAP based modeling), the percentage
increase in NOX emissions would be a 36% increase in
NOX emissions over the modeled emissions. Similarly, if one
compares the highest SO2 value from the reports (using
13,925 tpy from the reports and 100,174 tpy from the CENRAP based
modeling) the percentage increase in SO2 emissions would be
less than a 8% increase in SO2 emissions over the modeled
emissions. EPA believes that these are worst case scenario increases,
because they include the highest estimate of oil and gas development
emission from the reports supplied by the commenter, but they probably
overestimate the true increase over the inventories used for the
modeling, and double count the emissions of oil and gas that were in
the original modeling.
    EPA notes that these estimates also do not include the significant
reductions that have occurred in New Mexico from non oil and gas
sectors, such as federal motor vehicle controls and fleet turn over and
controls on SO2 and NOX emissions installed on
large stationary sources including the San Juan Generating Station. In
addition, emissions in other parts of the modeling domain outside of
New Mexico would be expected to have decreased after 2002 due to
federal and state controls including fleet turnover and would not have
been included in the CENRAP based modeling for ozone and only partially
included in the CAIR modeling.
    EPA relied on photochemical modeling conducted for CAIR for the
PM2.5 analysis in determining that New Mexico's emissions do
not make a significant contribution in areas in other states with
monitors showing violations of the 1997 PM2.5 NAAQS. As
discussed elsewhere in this notice, the modeling indicated that the
largest impact from New Mexico's emissions on any such monitor in
another state was only 15% of the significance level used in the final
CAIR rule. In the worst case estimate above, NOX emissions
could at most be 36% higher and SO2 could be at most 8%
higher than was modeled in CAIR. Although the impact on the model would
not necessarily be linear, EPA does not believe that such a relatively
small increase in total SO2 and NOX emissions
would increase the impact of New Mexico emissions by the more than 7
fold necessary to reach the significance level EPA used in CAIR for the
1997 PM2.5 NAAQS.
    EPA relied on photochemical modeling based on 2002 emission
inventories (available from CENRAP's efforts) in determining that New
Mexico's emissions do not make a significant contribution in areas in
other states with monitors showing violations of the 1997 8-hour ozone
NAAQS. EPA relied on this modeling to evaluate the possible
contribution from New Mexico sources to areas that were monitoring
violations of the 1997 8-hour NAAQS. EPA considers the modeling
conservative in that it used 2002 inventories, and for the entire
modeling grid (which covered most of the continental U.S. and parts of
Canada and Mexico), and it did not include the benefits from emission
reductions after 2002 from federal and state requirements including
fleet turnover. The modeling did not indicate values that were close to
the significance levels for New Mexico's impacts on out of state areas
which were nonattainment and/or monitoring nonattainment of the 1997 8-
hour ozone NAAQS. The area monitoring nonattainment with the highest
modeled impact from sources in New Mexico was the Dallas/Fort Worth
Area. The modeled daily average contribution from sources in New Mexico
was 0.4% with a contribution average of 0.4 ppb. EPA's screening
criteria for the first step of the analysis for any significant
contribution, established in CAIR and upheld by the court, were 1% and
2 ppb respectively. EPA believes that even a conservative estimate of a
36% increase in NOX emissions from New Mexico's sources
would not more than double New Mexico's impact on other states, even
before considering the other offsetting NOX emission
reductions between 2002 and 2010 from other source categories.
Therefore, EPA concludes that these new emission estimates would not
result in significant enough changes in impacts from New Mexico's
sources to change the determination that emissions from sources in New
Mexico do not significantly contribute to violations of the 1997 8-hour
ozone NAAQS in other states, based on available information.
Accordingly, New Mexico does not need to amend its SIP substantively to
reduce any additional emissions to prevent such impacts on other
states.
    Finally, EPA notes that photochemical modeling is a very detailed
and complicated process and there are continual refinements in emission
inventories and other modeling databases. Unfortunately, the statutory
and regulatory requirements, and especially the timing requirements,
for developing and evaluating SIPs do not allow for time or resources
to do every possible refinement to emission inventories on a continual
basis. In this specific case, EPA agrees that the sudden expansion of
oil and gas development and the emissions increases from such
activities are a source category for which emissions inventories need
updating, to insure that future regulatory actions by both states and
EPA continue to be based upon the most recent and accurate information
available
    EPA is concerned with the growth in emissions from oil and gas
development in New Mexico and other areas of the country, including
other states in Region 6. On May 10, 2010, EPA Region 6 held a meeting
with the principal oil and gas producers, trade organizations, and the
five States in the Region, with the goal of finding ways to improve the
emission inventory for these sources. Region 6 has initiated this
process because a clearer understanding of these emissions will be
necessary for future air quality plans under the new revised standards.
    Comment No. 16--The commenter also objected to EPA's proposed
approval because ``New Mexico's SIP, as written, simply does not
contain any

language that prohibits emissions that contribute significantly to
nonattainment in any other state.'' The commenter also noted that EPA
did not assess whether the SIP does or does not contain such
provisions. The commenter appears to have argued that 110(a)(2)(D)(i)
requires a state SIP to contain an explicit provision literally
prohibiting emissions that contribute significantly to nonattainment in
any other state and that, in order to approve the New Mexico interstate
transport SIP, EPA must examine the SIP to determine whether it
contains such an explicit prohibition.
    EPA Response--EPA disagrees with the commenter's interpretation of
the statutory requirements. Section 110(a)(2)(D)(i) has no language
that requires a SIP to contain a specific provision literally
prohibiting significant contribution to nonattainment in any other
state or, for that matter, to contain any particular words or generic
prohibitions. Instead, EPA believes that the statute requires a state's
SIP to contain substantive emission limits or other provisions that in
fact ensure that sources located within the state will not produce
emissions that have such an effect in other states. Therefore, EPA
believes that satisfaction of the ``significant contribution''
requirement is not to be demonstrated through a literal requirement for
a prohibition of the type advocated by the commenter.
    EPA's past application of section 110(a)(2)(D) did not require the
literal prohibition advocated by the commenter. For example, in the
1998 NOX SIP Call. \39\ EPA indicated that ``the term
`prohibit' means that SIPs must eliminate those amounts of emissions
determined to contribute significantly to nonattainment * * *.'' As a
result, the first step of the process to determine whether this
statutory requirement is satisfied is the factual determination of
whether emissions from sources in the State contribute significantly to
nonattainment in downwind areas.\40\ If this factual finding is in the
negative, as is the case for EPA's assessment of the contribution from
emissions from sources in New Mexico, then section 110(a)(2)(D)(i)(I)
does not require any changes to the State's SIP. If, however, the
evaluation reveals that there is such a significant contribution to
nonattainment in other States, then EPA requires the State to adopt
substantive provisions to eliminate those emissions. The state could
achieve these reductions through traditional command and control
programs, or at its own election, through participation in another
mechanism such as the cap and trade program of the NOX SIP
Call. Thus, EPA's approach in this action is consistent with the
Agency's interpretation of 110(a)(2)(D)(i) in the 2006 guidance, the
CAIR Rule, and the NOX SIP Call, none of which required the
pro forma literal ``prohibition'' of the type advocated by the
commenter.
---------------------------------------------------------------------------

    \39\ 63 FR 57356, October 27, 1998
    \40\ See 2005 CAIR Rule (70 FR 25162) and 1998 NOX
SIP Call (63 FR 57356).
---------------------------------------------------------------------------

    Comment No. 17--The commenter noted a specific provision for
stationary source permitting in the New Mexico SIP that the commenter
argued is inadequate to ensure that sources in New Mexico will not
significantly contribute to nonattainment in other States. According to
the commenter, New Mexico has a regulatory provision that requires the
State agency to deny an application for a permit or permit revision for
a stationary source under certain circumstances, including the
violation of any NAAQS. The commenter claimed that New Mexico
interprets this authority to allow the denial of such a permit, only if
the source is physically located in a designated nonattainment area.
    EPA Response--EPA disagrees with the commenter's characterization
of the State's regulations that New Mexico can only deny a permit for
new or modified sources located in a designated nonattainment area. EPA
has reviewed the New Mexico permitting provisions cited by the
commenter. Section <IP_ADDRESS> NMAC contains the reasons the department
must deny a permit. Section <IP_ADDRESS> D explicitly provides that one
of the reasons the State will deny a permit is if ``the construction,
modification, or permit revision will cause or contribute to air
contaminant levels in excess of any National Ambient Air Quality
Standard or New Mexico Ambient Air Quality Standard unless the ambient
air impact is offset by meeting the requirements of either 20.2.79 NMAC
or <IP_ADDRESS> NMAC, whichever is applicable.'' Section 20.2.79 NMAC
and <IP_ADDRESS> NMAC apply in nonattainment areas which have more
stringent requirements than attainment areas.
    EPA believes that the provisions of Section <IP_ADDRESS> NMAC apply
in attainment areas of the State and are unambiguous. The State's
regulations provide that it ``shall deny'' a permit for a source
located in an attainment area, if that new or modified source would
cause or contribute to air contaminant levels that exceed any NAAQS,
whether those violations occur in New Mexico or elsewhere. To verify
this understanding of the State's regulations, EPA contacted NMED
regarding this comment. NMED responded with an E-mail that is included
in the docket for this rulemaking confirming that the provisions of
<IP_ADDRESS> NMAC apply in the attainment areas of the State and provide
for denial of permits if the construction, modification or revision
will cause or contribute to levels in excess of the NAAQS.
    Comment No. 18--The commenter argued that EPA cannot approve the
section 110(a)(2)(D) submission from New Mexico because the State and
EPA did not comply with the requirements of section 110(l). Evidently,
the commenter believes that the section 110(a)(2)(D) submission for the
1997 8-hour ozone and 1997 PM2.5 NAAQS is a revision to the
SIP that will interfere with attainment of the 2006 PM2.5
NAAQS and the 2008 ozone NAAQS. The commenter argued that a section
110(l) analysis must consider all NAAQS once they are promulgated, and
argued that EPA recently took the same position in proposing to
disapprove a PM10 maintenance plan.
    EPA Response--EPA agrees that a required section 110(l) analysis
must consider the potential impact of a proposed SIP revision on
attainment and maintenance of all NAAQS that are in effect and impacted
by a given SIP revision. However, EPA disagrees that it failed to
comply with the requirements of section 110(l) in this action or that
section 110(l) requires disapproval of the SIP submission at issue
here.
    Section 110(l) provides in part that: ``the Administrator shall not
approve a revision of a plan if the revision would interfere with any
applicable requirement concerning attainment and reasonable further
progress * * *, or any other applicable requirement of this chapter.''
EPA has consistently interpreted Section 110(l) as not requiring a new
attainment demonstration for every SIP submission. EPA has further
concluded that preservation of the status quo air quality during the
time new attainment demonstrations are being prepared will prevent
interference with the States' obligations to develop timely attainment
demonstrations. 70 FR 58,199, 58,134 (Oct. 5. 2005); 70 FR 17.029,
17,033 (Apr. 4, 2005); 70 FR 53, 57 (Jan. 3, 2005); 70 FR 28,429,
28,431 (May 18, 2005).
    New Mexico's submission is the initial submission by the State to
address the significant contribution to nonattainment element of
110(a)(2)(D)(i) for the 1997 8-hour ozone and 1997 PM2.5
NAAQS. This submission does not revise or remove any existing emissions
limit for any NAAQS, or

change any other existing substantive SIP provisions relevant to the
1997 8-hour ozone or 1997 PM2.5 NAAQS or any other NAAQS.
Simply put, it does not make any substantive revision that could result
in any change in emissions. As a result, the submission does not relax
any existing requirements or alter the status quo air quality.
Therefore, approval of the submission will not interfere with
attainment or maintenance of any NAAQS.
    EPA's discussion in the notice cited by the commenter concerning a
PM10 maintenance plan in another state is consistent with this
interpretation. In the cited action, EPA noted that: ``Utah had either
removed or altered a number of stationary source requirements,''
creating the possibility of a relaxation of existing EPA approved SIP
requirements and thereby interfering with attainment, a possibility
that is not present here. See 74 FR 62727 (Dec. 1, 2009). Thus, the
action cited by the commenter is clearly distinguishable.
    The commenter did not provide any specific basis for concluding
that approval of this SIP submission would interfere with attainment or
maintenance of any NAAQS, or with any other applicable requirement of
the Clean Air Act. EPA concludes that approval of the submission will
not make the status quo air quality worse, and is in fact consistent
with the development of an overall plan capable of meeting the Act's
attainment requirements. In particular, EPA has determined that the
submission complies with the requirements of section 110(a)(2)(D)(i).
Accordingly, assuming that section 110(l) applies to this SIP
submission, EPA finds that approval of the submission is consistent
with the requirements of section 110(l).
    Comment No. 19--In a separate comment letter, the commenter
expressed concern with EPA's proposed approval of the State's
submission for the 1997 8-hour ozone NAAQS and 1997 PM2.5
NAAQS because the state ``does not appropriately limit ozone'' in its
PSD permitting program. To support this claim, the commenter noted that
EPA has previously made a ``finding of failure to submit'' because New
Mexico had not made another submission that would have the effect of
making NOX a regulatory precursor for ozone in the context
of PSD. According to the commenter, EPA should not approve the State's
submission for section 110(a)(2)(D)(i)(I) for the significant
contribution to nonattainment requirement because of this outstanding
obligation with respect to the PSD requirements of the CAA for the 1997
8-hour ozone NAAQS.
    EPA Response--EPA acknowledges that it made the finding of failure
to submit noted by the commenter.\41\ However, EPA disagrees with the
commenter's view of how that prior finding affects today's specific
action. First, the ``finding of failure to submit'' to which the
commenter refers is not for a failure to make a submission with respect
to section 110(a)(2)(D). In that prior action, EPA made a formal
finding that the State had, at that time, not yet made a different SIP
submission, necessary to comply with a separate requirements of section
110(a)(2)(C) and section 110(a)(2)(J).
---------------------------------------------------------------------------

    \41\ See, Completeness Findings for Section 110(a)(2) State
Implementation Plans for the 8-hour Ozone NAAQS, 73 FR 16,205 (March
28, 2008).
---------------------------------------------------------------------------

    Second, EPA believes that the cited finding of failure to submit
does not relate to the requirements of section 110(a)(2)(D)(i)(I) with
respect to significant contribution to nonattainment at issue in this
action, but rather to the separate requirements of section
110(a)(2)(D)(i)(II) that SIPs include measures to prevent interference
with measures required for ``prevention of significant deterioration.''
EPA's 2006 Guidance explained the Agency's views of what the four
separate and distinct elements of section 110(a)(2)(D) require.\42\
EPA's guidance made recommendations to States for making submissions to
meet each of the separate requirements of section 110(a)(2)(D) for the
1997 8-hour ozone standards and 1997 PM2.5 standards. Within
the guidance, EPA recommended that States evaluate the existence of,
and extent of, significant contribution to nonattainment in other
States by various means, intended to consider relevant facts about such
contribution to nonattainment. By contrast, EPA recommended that States
meet the separate requirement that their SIPs contain measures to
prevent interference with measures required to prevent significant
deterioration of air quality in other States by different means. In
particular, EPA explained that this latter element of section
110(a)(2)(D) would be the correct context in which to confirm that the
State in question had updated its own SIP to contain measures related
to PSD.
---------------------------------------------------------------------------

    \42\ ``Guidance for State Implementation Plan (SIP) Submission
to Meet Current Outstanding Obligations Under Section
110(a)(2)(D)(i) for the 8-Hour Ozone and PM2.5 National
Ambient Air Quality Standards'' August 15, 2006.
---------------------------------------------------------------------------

    In the 2006 Guidance, EPA explicitly identified the regulatory
requirements and separate SIP revision necessary to implement the PSD
program for the 1997 8-hour ozone NAAQS as among the requirements that
EPA considered relevant to the prevention of significant deterioration
requirements of section 110(a)(2)(D).\43\ EPA stated its view that
implementation of the PSD permitting program within the State would
address the requirement to prohibit emissions that interfere with
measures to prevent significant deterioration in neighboring States.
EPA also explained that the permitting program for the 8-hour ozone
NAAQS would require that new or modified sources will not cause or
contribute to violations of the NAAQS in neighboring States, so that
additional SIP submissions with rule changes or modeling demonstrations
would not be required to establish that a State's program complies with
the requirement in section 110(a)(2)(D)(i)(II). In short, EPA believes
that evaluation of a State's SIP for compliance with section
110(a)(2)(D)(i)(II) is the proper context in which to determine whether
such SIP meets current federal PSD requirements. Today's action does
not address this element of section 110(a)(2)(D), and accordingly, the
finding of failure to submit is not a basis not to approve the State's
submission for this purpose.
---------------------------------------------------------------------------

    \43\ Id, at pages 6-8.
---------------------------------------------------------------------------

    Finally, EPA notes that the State of New Mexico has subsequently
made a submission to comply with the rule that was the basis for the
finding of failure to submit cited by the commenter. EPA is in the
process of evaluating that submission and will act on it at a later
date. EPA anticipates that it may elect to act upon that separate
submission at the same time it acts upon the State's section
110(a)(2)(D) submission for the prevention of significant deterioration
requirement, as EPA has recently done in the case of the section
110(a)(2)(D) submission for the State of North Dakota.

B. Comments From New Mexico Environment Department, Air Quality Bureau

    Comment No. 1--The commenter stated that while it did not object to
EPA's proposed approval of the ``contribute to nonattainment'' prong of
section 110(a)(2)(D)(i) of the CAA, it believed that EPA should have
approved the SIP submission as meeting all prongs of that section. The
commenter asserted its belief that New Mexico satisfied all
requirements of section 110(a)(2)(D) for the 1997 8-hour ozone and 1997
PM2.5 NAAQS in its submission, following EPA's
recommendations in the 2006 Guidance for this SIP revision.
    EPA Response--We appreciate NMED's comments. At this time, EPA is
only taking action on the portions of the

State's submission that pertain to the significant contribution to
nonattainment requirements of section 110(a)(2)(D) for the 1997 8-hour
ozone and 1997 PM2.5 NAAQS. EPA will act on the remaining
requirements of section 110(a)(2)(D) for these NAAQS at a later date.

IV. Final Action

    We are approving one element of the Interstate Transport SIP
submitted by the State of New Mexico on September 17, 2007.
Specifically, in this action we are approving the element that
addresses the requirement of Section 110(a)(2)(D)(i)(I) that emissions
from sources in that State do not ``contribute significantly'' to
violations of the 1997 8-hour ozone or 1997 PM2.5 NAAQS in
any other State. After fully considering all comments received on the
proposal and direct final rule EPA has concluded that the State's
submission, and additional evidence evaluated by EPA, establish that
emissions from New Mexico sources do not contribute significantly to
nonattainment of the relevant NAAQAS in any other State. Accordingly,
New Mexico does not need to include additional emission limitations on
its sources to eliminate any such contribution to other States for
purposes of these NAAQS.
    At a later date, EPA will act on addressing the remaining
requirements of section 110(a)(2)(D)(i) which are: interference with
the maintenance of the NAAQS in any other state; interference with
measures required to prevent significant deterioration of air quality
in any other State; and interference with measures required to protect
visibility in any other State.

V. Statutory and Executive Order Reviews

    Under the Clean Air Act, the Administrator is required to approve a
SIP submission that complies with the provisions of the Act and
applicable Federal regulations. 42 U.S.C. 7410(k); 40 CFR 52.02(a).
Thus, in reviewing SIP submissions, EPA's role is to approve State
choices, provided that they meet the criteria of the Clean Air Act.
Accordingly, this action merely 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 28355, May 22, 2001);
     Is not subject to requirements of Section 12(d) of the
National Technology Transfer and Advancement Act of 1995 (15 U.S.C. 272
note) because application of those requirements would be inconsistent
with the Clean Air Act; and
     Does not provide EPA with the discretionary authority to
address, as appropriate, disproportionate human health or environmental
effects, using practicable and legally permissible methods, under
Executive Order 12898 (59 FR 7629, February 16, 1994).
    In addition, this 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.
    The Congressional Review Act, 5 U.S.C. 801 et seq., as added by the
Small Business Regulatory Enforcement Fairness Act of 1996, generally
provides that before a rule may take effect, the agency promulgating
the rule must submit a rule report, which includes a copy of the rule,
to each House of the Congress and to the Comptroller General of the
United States. EPA will submit a report containing this action and
other required information to the U.S. Senate, the U.S. House of
Representatives, and the Comptroller General of the United States prior
to publication of the rule in the Federal Register. A major rule cannot
take effect until 60 days after it is published in the Federal
Register. This action is not a ``major rule'' as defined by 5 U.S.C.
804(2).
    Under section 307(b)(1) of the Clean Air Act, petitions for
judicial review of this action must be filed in the United States Court
of Appeals for the appropriate circuit by August 10, 2010. Filing a
petition for reconsideration by the Administrator of this final rule
does not affect the finality of this action for the purposes of
judicial review nor does it extend the time within which a petition for
judicial review may be filed, and shall not postpone the effectiveness
of such rule or action. This action may not be challenged later in
proceedings to enforce its requirements. (See section 307(b)(2).)

List of Subjects in 40 CFR Part 52

    Environmental protection, Air pollution control, Incorporation by
reference, Intergovernmental relations, Ozone, Particulate matter,
Reporting and recordkeeping requirements, Volatile organic compounds.

    Dated: May 28, 2010.
Lawrence E. Starfield,
Acting Regional Administrator, Region 6.

0
40 CFR Part 52 is amended as follows:

PART 52--[AMENDED]

0
1. The authority citation for part 52 continues to read as follows:

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

Subpart GG--New Mexico

0
2. The second table in Sec.  52.1620(e) entitled ``EPA-Approved
Nonregulatory Provisions and Quasi-Regulatory Measures in the New
Mexico SIP'' is amended by adding an entry to the end to read as
follows:

Sec.  52.1620  Identification of plan.

* * * * *
    (e) * * *

            EPA-Approved Nonregulatory Provisions and Quasi-Regulatory Measures in the New Mexico SIP
----------------------------------------------------------------------------------------------------------------
                                       Applicable
      Name of SIP provision          geographic or     State submittal/  EPA approval date       Explanation
                                   nonattainment area   effective date
----------------------------------------------------------------------------------------------------------------

                                                  * * * * * * *
Interstate transport for the      New Mexico.........        09/17/07   06/11/10 [insert FR  06/11/10 Approval
 1997 ozone and PM 2.5 NAAQS.                                            page number where    for revisions to
                                                                         the document         prohibit
                                                                         begins].             significant
                                                                                contribution to
                                                                                nonattainment in
                                                                                any other State.
----------------------------------------------------------------------------------------------------------------

[FR Doc. 2010-13686 Filed 6-10-10; 8:45 am]
BILLING CODE 6560-50-P