[Federal Register Volume 75, Number 106 (Thursday, June 3, 2010)]
[Rules and Regulations]
[Pages 31306-31317]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2010-13050]
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ENVIRONMENTAL PROTECTION AGENCY
40 CFR Part 52
[EPA-R08-OAR-2007-1032; FRL-9155-5]
Approval and Promulgation of State Implementation Plans; State of
Colorado; Interstate Transport of Pollution Revisions for the 1997 8-
hour Ozone NAAQS: ``Significant Contribution to Nonattainment''
Requirement
AGENCY: Environmental Protection Agency (EPA).
ACTION: Final rule.
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SUMMARY: EPA is partially approving State Implementation Plan (SIP)
revisions submitted by the State of Colorado on June 18, 2009. These
revisions, referred to as the Colorado Interstate Transport SIP,
address the requirements of Clean Air Act section 110(a)(2)(D)(i)(I)
for the 1997 8-hour ozone National Ambient Air Quality Standards
(NAAQS). In this action EPA is approving the Colorado Interstate
Transport SIP non-regulatory provisions that address the requirement of
section 110(a)(2)(D)(i)(I) that emissions from the state's sources do
not ``contribute significantly'' to nonattainment of the 1997 8-hour
ozone NAAQS in any other state. EPA will act at a later date on the
Colorado Interstate Transport SIP provisions that address the
requirement of section 110(a)(2)(D)(i)(I) that emissions from the
state's sources do not ``interfere with maintenance'' of the 1997 8-
hour ozone NAAQS in any other state. This action is being taken under
section 110 of the Clean Air Act.
DATES: Effective Date: This final rule is effective July 6, 2010.
ADDRESSES: EPA has established a docket for this action under Docket ID
No. EPA-R08-OAR-2007-1032. All documents in the docket are listed on
the http://www.regulations.gov Web site. Although listed in the index,
some information is not publicly available, e.g., Confidential Business
Information (CBI) 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 http://www.regulations.gov, or in hard copy at
the Air Program, Environmental Protection Agency (EPA), Region 8, 1595
Wynkoop Street, Denver, Colorado 80202-1129. EPA requests that if at
all possible, you contact the individual listed in the FOR FURTHER
INFORMATION CONTACT section to view the hard copy of the docket. You
may view the hard copy of the docket Monday through Friday, 8:00 a.m.
to 4:00 p.m., excluding Federal holidays.
FOR FURTHER INFORMATION CONTACT: Domenico Mastrangelo, Air Program,
U.S. Environmental Protection Agency, Region 8, Mailcode 8P-AR, 1595
Wynkoop Street, Denver, Colorado 80202-1129, (303) 312-6416,
[email protected].
SUPPLEMENTARY INFORMATION:
Definitions
For the purpose of this document, we are giving meaning to certain
words or initials as follows:
(i) The words or initials Act or CAA mean or refer to the Clean Air
Act, unless the context indicates otherwise.
[[Page 31307]]
(ii) The words EPA, we, us or our mean or refer to the United
States Environmental Protection Agency.
(iii) The initials SIP mean or refer to State Implementation Plan.
(iv) The words State or Colorado mean the State of Colorado, unless
the context indicates otherwise.
Table of Contents
I. Background
II. Response to Comments
III. Section 110(l)
IV. Final Action
V. Statutory and Executive Order Reviews
I. Background
Section 110(a)(2)(D)(i) of the CAA requires that a state's SIP must
contain adequate provisions prohibiting any source or other type of
emissions activity within the state from emitting any air pollutant in
amounts which will: (1) Contribute significantly to nonattainment of
the NAAQS in any other state; (2) interfere with maintenance of the
NAAQS by any other state; (3) interfere with any other state's required
measures to prevent significant deterioration of air quality; or (4)
interfere with any other state's required measures to protect
visibility. On March 31, 2010, EPA published a notice of proposed
rulemaking (NPR) proposing partial approval of the State Implementation
Plan (SIP) revision ``State of Colorado Implementation Plan to Meet the
Requirements of Clean Air Act Section 110(a)(2)(D)(i)(I)--Interstate
Transport Regarding the 1997 8-Hour Ozone Standard,'' submitted by the
State on June 18, 2009. As indicated by the title, this SIP addresses
the first two of the four requirements listed above-i.e., (1),
``significant contribution,'' and (2), ``interference with
maintenance.'' EPA's proposed rule action reviewed and proposed
approval of the Colorado SIP's section addressing only the
``significant contribution'' requirement. EPA will act at a later date
on the Colorado Interstate Transport SIP section that addresses the
``interference with maintenance'' requirement.
To assess whether emissions from Colorado contribute significantly
to downwind nonattainment for the 1997 8-hour ozone NAAQS, EPA's
technical analysis relied on EPA's 2006 Guidance, recommending
consideration of available EPA modeling conducted in conjunction with
CAIR,\1\ or in the absence of such EPA modeling, consideration of other
information such as the amount of emissions, the geographic location of
violating areas, meteorological data, or various other forms of
information that would be relevant to assessing the likelihood of
significant contribution to violations of the NAAQS in another state.
Consistent with the NOX SIP Call and CAIR, our technical
analysis assessed the extent of ozone transport from Colorado not just
to areas designated nonattainment, but also to areas in violation of
the NAAQS. Because EPA did not have detailed modeling for Colorado and
nearby downwind states, our approach did not rely on a quantitative
determination of Colorado's contribution but on a weight-of-evidence
approach using quantitative information such as Colorado's distance
from areas with monitors showing violations of the NAAQS, modeling
results outlining wind vectors for regional transport of ozone on high
ozone days, back trajectory analyses for the downwind nonattainment
areas closest to the State, and results of modeling studies for the
nonattainment areas specifying the range of wind directions along which
contribution of ozone transport occurred. Given that the assessments
for each of these pieces of evidence are not individually definitive or
outcome determinative, EPA concluded in its proposed action that the
various factual and technical considerations supported a determination
of no significant contribution from Colorado emissions to the ozone
nonattainment areas noted above. EPA did not receive comments that
persuade the Agency that there is such significant contribution, and
thus in today's final action EPA is making a final regulatory
determination that Colorado emissions sources do not contribute
significantly to violations of the 1997 8-hour ozone NAAQS in any other
state.
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\1\ 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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II. Response to Comments
EPA received one letter from WildEarth Guardians (WG) commenting on
EPA's Federal Register action proposing approval of the portion of the
Colorado Interstate Transport SIP that addresses the ``significant
contribution to nonattainment'' requirement of CAA Section
110(a)(2)(D)(i)(I) for the 1997 8-hour ozone NAAQS. In this section EPA
responds to the significant adverse comments made by the commenter.
Comment No. 1--The commenter asserted that EPA's proposed approval
was based on a ``flawed legal standard.'' According to the commenter,
EPA erred in the proposal by explaining that various factual or
technical assessments indicate that it is ``unlikely'' that emissions
from Colorado sources significantly contribute to violations of the 8-
hour ozone NAAQS in other states. The commenter's position was that EPA
cannot approve a SIP submission based upon ``unlikelihood'' because CAA
Section 110(a)(2)(D)(i)(I) prohibits emissions that contribute
significantly to nonattainment in other States and does not allow EPA
to approve SIPs simply because a state's emissions are ``unlikely'' to
contribute significantly to nonattainment.
EPA Response--EPA disagrees with the commenter's characterization
of EPA's analysis and the commenter's interpretation of the statutory
requirements. First, EPA notes that the discussion in the proposal was
intended to present the various factual and technical considerations
available to assess whether there is or is not significant contribution
to nonattainment in other states as a result of emissions from Colorado
sources. Given that these assessments are not individually definitive
or outcome determinative, EPA believes that it is entirely appropriate
to present and describe the relative probative value of the various
considerations accurately. Second, EPA notes that all such technical
evaluations are by their nature subject to some degree of uncertainty.
Indeed, the modeling that the commenter elsewhere contends should be
the sole method for evaluating interstate transport is itself but one
means of evaluating the real world impacts of emissions in light of
meteorological conditions, wind direction, and other such variables and
produces a result that is itself subject to some degree of uncertainty.
Third, EPA believes that it was also appropriate to describe the
various factual and technical considerations and whether they indicated
a ``likelihood'' of significant contribution to nonattainment in
another state because the proposal was seeking comment from the public
upon whether these considerations together supported a determination of
no such significant contribution. EPA did not receive comments that
persuade the Agency that there is such significant contribution, and
thus in today's final action EPA is making a final regulatory
determination that Colorado emissions sources do not significantly
contribute to violations of the 1997 8-hour ozone NAAQS in any other
state, for the reasons explained elsewhere in this notice. In other
words, EPA has concluded that the existing SIP for Colorado already
contains adequate
[[Page 31308]]
provisions to prevent emissions from Colorado sources from
significantly contributing to violations of the 1997 8-hour ozone NAAQS
in other states and is therefore approving Colorado's submission for
this purpose.
Comment No. 2--The commenter argued that Colorado and EPA did not
appropriately assess impacts to nonattainment in downwind states.
According to the commenter, Colorado failed to assess significance of
downwind impacts in accordance with EPA guidance and precedent.
Although this is unclear from the comment, the commenter evidently
believes that EPA's applicable guidance for this purpose appears only
in the 1998 NOX SIP call. The commenter asserts that, based
on the precedent of the NOX SIP Call, the following issues
need to be addressed in determining whether or not an area is
significantly contributing to nonattainment in downwind States: (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. (63 FR 57356-
57376, October 27, 1998).
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 that 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 necessarily 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 making recommendations to
states about how to address section 110(a)(2)(D) in SIP submissions for
the 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.\2\ 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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\2\ 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. An electronic copy is
available for review at the regulations.gov web site as Document ID
No. EPA-R08-OAR-2007-1032.0004.1.
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Within that 2006 guidance document, 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.'' \3\ 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.'' \4\ To that end, EPA
specifically recommended that states located within the geographic
region covered by the ``Clean Air Interstate Rule'' (CAIR) \5\ 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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\3\ Id. at 3.
\4\ Id.
\5\ 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.'' \6\ 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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\6\ 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 Colorado submission and EPA's
evaluation of it was consistent with EPA's guidance for the 1997 8-hour
ozone NAAQS. For example, as discussed in the proposal notice, the
state and EPA considered information such as monitoring data in
Colorado and downwind 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 document are consistent with the
concepts that the commenter enumerated from the NOX SIP Call
context: (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 Colorado submission
at issue here would be that because the available evidence indicates
that there is very little contribution from emissions from Colorado
sources to nonattainment in other states, it is not necessary to
[[Page 31309]]
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. 3--The commenter argued that Colorado based its claim
of no significant contribution ``primarily on attainment plan modeling
for the Denver Metropolitan Area/North Front Range (DMA/NFR)
nonattainment area'' and noted that EPA itself ``does not accept'' that
modeling for purposes of assessing impacts on nonattainment in downwind
States.
EPA Response--EPA disagrees with the commenter's characterization
of the state's submission and of EPA's evaluation of it. This comment
reflects an incomplete reading of EPA's evaluation of how the results
of Colorado's modeling analysis for the DMA/NFR relate to an assessment
of whether emissions from Colorado sources contribute significantly to
downwind nonattainment of the 1997 8-hour ozone NAAQS in other states.
It is correct that the State relied upon this information in its
submission to EPA. It is correct that EPA did not agree with Colorado's
view that the modeling analysis results for the DMA/NFR attainment
plan, in and of themselves, prove that there could be no significant
contribution from Colorado sources to downwind ozone nonattainment in
other states. EPA explicitly disagreed with the state's belief that: ``
* * * these results [of the DMA/NFR modeling analysis] demonstrate that
the magnitude of ozone transport from Colorado to other States is too
low to significantly contribute to nonattainment. * * *.''
Nevertheless, EPA did agree that these modeling results were a
relevant piece of information that could be useful when considered in
conjunction with other information. EPA stated that these modeling
results do support the conclusion that there is not significant
transport of ozone from Colorado to other states with violations of the
NAAQS: `` * * * [h]owever, as a reflection of emission levels, the
relatively (to the 1997 8-hour ozone NAAQS) moderate concentrations in
eastern Colorado * * * somewhat reduce the probability of significant
contribution from Colorado emission sources to considerably farther
downwind nonattainment areas such as St. Louis, Missouri, and Chicago,
Illinois.'' (See 75 FR 16034-35). The commenter suggests that EPA
approved the State's submission based wholly upon technical support
that EPA itself rejected and this is incorrect.
Comment No. 4--The commenter reiterated its concern that the
Colorado section 110(a)(2)(D) submission was deficient because it did
not strictly follow the commenter's summary of the structure of the
analysis of interstate transport in the NOX SIP Call: (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.
EPA Response--EPA disagrees with the commenter's view that any
analysis of interstate transport must follow a specific formulaic
structure to be approvable. As noted above, EPA issued specific
guidance to states making recommendations for section 110(a)(2)(D) SIP
submissions for the 1997 8-hour ozone NAAQS. Within that guidance, EPA
recommended various types of information that states might wish to
consider in the process of evaluating whether their sources contributed
significantly to nonattainment in other states. EPA has concluded that
the submission from Colorado, augmented by EPA's own analysis,
sufficiently establishes that Colorado sources do not significantly
contribute to violations of the 1997 8-hour ozone NAAQS in other
states. As noted above, EPA believes that the state's submission, and
EPA's analysis of it, address the same conceptual considerations that
the commenter advocated.
Comment No. 5--The commenter asserted that Colorado and EPA
provided ``no analysis'' of the contribution from Colorado to downwind
states and no ``actual assessment'' of the significance of any such
contribution.
EPA Response--EPA disagrees with the commenter's position. The
commenter again assumes that section 110(a)(2)(D) explicitly requires
the type of modeling analysis that the commenter advocates throughout
its comments. Because the commenter apparently views the NOX
SIP Call as the applicable guidance, the commenter contends that any
analytical approach that is not identical to that approach is
impermissible. In addition, the commenter overlooks the fact that in
other actions based upon section 110(a)(2)(D), EPA has also used a
variety of analytical approaches, short of modeling, to evaluate
whether specific states are significantly contributing to violations of
the NAAQS in another state (e.g., the west coast states that EPA
concluded should not be part of the geographic region of the CAIR rule
based upon qualitative factors, and not by the zero out modeling EPA
deemed necessary for some other States).
In the proposed approval, EPA explained that other forms of
available information were sufficient to make the determination that
there is no significant contribution from Colorado sources to downwind
nonattainment of the 1997 8-hour ozone NAAQS. As stated in the
proposal:
``EPA's evaluation of whether emissions from Colorado contribute
significantly to ozone nonattainment in these areas [St. Louis and
Chicago] relies on an examination of a variety of data and analysis
that provide insight on ozone transport from Colorado to these two
areas. Because EPA does not have detailed modeling for Colorado and
nearby downwind states, our approach does not rely on a quantitative
determination of Colorado's contribution, as EPA did for other
states in its CAIR rulemaking, but on a weight-of-evidence analysis
based on qualitative assessments and estimates of the relevant
factors. While conclusions reached for each of the factors
considered in the following analysis are not in and by themselves
determinative, consideration of all of these factors provides a
reliable qualitative conclusion on whether Colorado's emissions are
likely to contribute significantly to nonattainment in the St. Louis
and the Illinois/Wisconsin areas.''
EPA acknowledged that the various forms of information considered
in the proposal (such as distance, orientation of surface and regional
transport winds, back trajectory analyses, monitoring data) were not
individually outcome determinative, but concluded that when taken
together served to establish that Colorado sources do not significantly
contribute to downwind nonattainment of the 1997 8-hour ozone NAAQS in
other states. Thus, contrary to the commenter's assertion, EPA did
perform an ``analysis'' and an ``assessment'' that was a reasonable
basis for its conclusion that emissions from Colorado do not contribute
significantly to downwind ozone nonattainment, using a combination of
quantitative data and qualitative analyses. EPA does not agree that
only the type of analysis advocated by the commenter could adequately
evaluate the issue and support a rational determination in this
instance.
Comment No. 6--The commenter objected to EPA's proposed approval
because Colorado assessed impacts in downwind states by considering
monitoring data in those states as a means of evaluating significant
contribution to nonattainment. In other
[[Page 31310]]
words, the commenter is concerned that Colorado did not assess impacts
in areas that have no monitor. The commenter likewise objected to EPA's
``endorsement'' of this approach. The commenter argued 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.\7\
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\7\ Michigan v. U.S. EPA, 213 F.3d 663, 674-681 (D.C. Cir.
2000); North Carolina v. EPA, 531 F.3d 896, 913-916 (D.C. 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. First, neither
section 110(a)(2)(D)(i)(I) provisions, nor the EPA guidance issued for
the 1997 8-hour ozone NAAQS on August 15, 2006, support the commenter's
position, as neither refers to any explicit mandatory or recommended
approach to assess air quality in non-monitored areas.\8\ The same
focus on monitored 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.\9\ 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 in a
particular area. Put another way, in order for there to be significant
contribution to nonattainment for the 1997 8-hour ozone 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 Colorado 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.
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\8\ 2006 Guidance, p. 5.
\9\ ``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,'' 62 FR 60336.
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Comment No. 7--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''). The
commenter asserted that: ``Slide 28 of this presentation displays
projected 4th highest 8-hour ozone reading for 2018 and indicates that
air quality in areas such as northern New Mexico, western Wyoming,
southern Utah, and central Arizona will exceed and/or violate the 1997
ozone
[[Page 31311]]
NAAQS * * *.'' \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 Colorado.
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\10\ The presentation is available for review as Document ID
EPA-R08-OAR-2007-1032-0007.8 at Regulations.gov, Docket ID
EPA-R08-OAR-2007-1032.
---------------------------------------------------------------------------
EPA Response--EPA disagrees with this comment on several grounds.
First, as explained in response to other comments, EPA does not agree
that it is appropriate 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 4th max 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 4th max above the NAAQS only constitutes an
exceedance of the NAAQS; to constitute a violation of the 1997 8-hour
ozone NAAQS, the standard must be exceeded for three consecutive years
at the same monitor. 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
Colorado's neighboring States.
Finally, 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; Stoeckenius et al., 2009) 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.\11\ 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 expanses
of 8-hour ozone nonattainment areas projected for 2018 in areas without
monitors.
---------------------------------------------------------------------------
\11\ 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. 8--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 ``Uinta Basin Air Quality Study (UBAQS).'' The commenter
argued that UBAQS further supports its concern that Colorado 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 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 southwest corner of Utah are also
currently in nonattainment and will be in nonattainment in 2012.\12\
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\12\ 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. Even
taking the UBAQS modeling results at face value, however, EPA does not
agree that the 8-hour ozone nonattainment (current and projected) in
the Wasatch Front Range area supports the commenter's concerns about
the need to evaluate the possibility of significant contribution to
nonattainment in non-monitored areas. 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.''
First, the commenter's interpretation of the predicted ozone
concentrations shown in Figures 4-3a and 4-3b (pages 5 and 6 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 it is not specified. If it is actually
predicted smaller than or equal to 84.9 ppb then the area is attaining
the 1997 8-hour ozone NAAQS, if it is predicted as greater than 84.9
ppb then it is not attaining those NAAQS. Thus, the current and
predicted design values for the 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.
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.\13\ The study
deviates in at least two significant ways from EPA's 2007 guidance on
SIP modeling.\14\ One issue is the UBAQS modeling reliance on fewer
than the five years of data recommended by EPA to generate a current 8-
hour ozone 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 issue is the computation of the relative responsive
factor (RRF), which directly affects the modeling's future design value
(DVF).\15\ Again 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
[[Page 31312]]
ppb, UBAQS modeling uses RRFs based on one or more days of ozone
concentrations above 70 ppb.\16\ EPA concludes that the modeling
analysis results used by the WG are unreliable for projecting non-
attainment status and therefore do not support its comments.
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\13\ See UBAQS, pp. 4-27 to 4-29.
\14\ 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.
\15\ DVC x RRF = DVF.
\16\ See UBAQS, p. 4-28
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Comment No. 9--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 monitor 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 relying on monitoring
data instead of modeling ambient levels.
EPA Response--EPA does not disagree that there are relatively few
monitors in the western states, and that relatively few 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 that
are the subject of this rulemaking, but rather the next iteration of
the ozone NAAQS for which there are concerns that 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 newer ozone NAAQS does not automatically
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 they meet the applicable requirements.
For example, Colorado itself submits just such a report on an
annual basis, and EPA reviews it for adequacy.\17\ All other 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 Colorado
sources in reliance on those monitors is incorrect.
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\17\ See, for example, ''Colorado Annual Monitoring Network
Plan'' dated 2009-2010. Plan is available for review at the
regulations.gov Web site under Docket ID No. EPA-R08-OAR-2007-1032.
---------------------------------------------------------------------------
Comment No. 10--The commenter objected to EPA's proposed approval
of the Colorado SIP submission because neither Colorado nor EPA
performed a specific modeling analysis to assure that emissions from
Colorado sources do not significantly contribute to nonattainment in
downwind States. According to the commenter, EPA's decision to use a
qualitative approach to determine whether emissions from Colorado
contribute significantly to downwind nonattainment is not consistent
with its own preparation of a regional model to evaluate such impacts
from other states as part of CAIR.
EPA Response--EPA disagrees with the commenter's belief that only
modeling can establish whether or not there is significant contribution
from one state to another. First, 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 part of
their section 110(a)(2)(D) submissions for the 1997 8-hour ozone NAAQS.
EPA has concluded that its qualitative approach to the assessment of
significant contribution to downwind ozone nonattainment is consistent
with EPA's 2006 Guidance.
Second, EPA notes that the commenter's position also reflects a
misunderstanding of the approach EPA used in the remanded CAIR due to
an exclusive focus on those States that were selected for the modeling
analysis. A wider understanding of the CAIR approach would recognize
that EPA decided, based on other criteria, that it was not necessary to
conduct modeling for certain western states: ``[i]n analyzing
significant contribution to nonattainment, we determined it was
reasonable to exclude the Western U.S., including the States of
Washington, Idaho, Oregon, California, Nevada, Utah, and Arizona from
further analysis due to geography, meteorology, and topography. Based
on these factors we concluded that the PM2.5 and 8-hour
ozone nonattainment problems are not likely to be affected
significantly by pollution transported across these States' boundaries
* * *.'' (69 FR 4581, January 30, 2004).
EPA has taken a similar approach to assess whether Colorado
contributes significantly to violations of the 1997 8-hour ozone NAAQS
in downwind states. In the proposed action, EPA explained several forms
of substantive and technically valid evidence that led to the
conclusion that emissions from the Colorado sources do not contribute
significantly to nonattainment, in accordance with the requirement of
Section 110(a)(2)(D).
Comment No. 11--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.\18\ 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 Colorado 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 that the statewide
emissions at issue in an evaluation under section 110(a)(2)(D).
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\18\ WG's April 9, 2010 comment letter, pp. 9-10. 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-R08-OAR-2007-1032-
0007.4 through 1032-0007.7.
---------------------------------------------------------------------------
EPA Response--As explained above, 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
[[Page 31313]]
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. Even EPA's own CAIR analysis relied on a combination of
qualitative and quantitative analyses, as explained above. EPA's CAIR
analysis excluded certain western states on the basis of a qualitative
assessment of topography, geography, and meteorology.\19\
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\19\ See 69 FR 4581, January 30, 2004.
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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 NEPA,
not the Clean Air Act. As explained above, in the context of section
110(a)(2)(D), EPA does not agree that modeling is always required to
make that different evaluation, and EPA itself has relied on other more
qualitative evidence when it deemed that evidence sufficient to reach a
reasoned determination.
Comment No. 12--In further support of its argument that EPA should
always require 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).
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 Colorado do not contribute significantly to nonattainment for the
1997 8-hour ozone standard 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). Thus, the commenter's
cited regulation is not relevant to EPA's technical demonstration
assessing whether emissions from Colorado contribute significantly to
nonattainment in any other states under section 110(a)(2)(D).
Comment No. 13--The commenter also objected to EPA's proposed
approval of the Colorado submission on the grounds that it was based
upon a ``weight-of-evidence analysis,'' and that no such weight of
evidence test appears in the CAA generally, or in section 110(a)(2)(D)
in particular. According to the commenter, there is no regulatory
support for using a ``weight-of-evidence'' approach to assessing air
quality impacts. The commenter asserted that EPA neither cited nor
quoted regulations or policy that provides for this, and failed to lend
any specific meaning to the phrase through its proposed approval.
Finally, the commenter asserted, without explaining, its belief that
EPA failed to address ``several relevant factors related to the
determination of whether Colorado contributes significantly to
nonattainment undermines the agency's reliance on any `weight-of-
evidence' approach.''
EPA Response--The fact that neither the CAA generally, nor section
110(a)(2)(D) specifically, include the explicit phrase ``weight of
evidence'' does not mean that it is inappropriate for EPA to use such
an approach in this context. As explained above, section 110(a)(2)(D)
does not explicitly stipulate how EPA is to assess whether there is a
significant contribution to nonattainment in other states. The proper
consideration, therefore, is whether EPA has a rational technical basis
for its decision. Even if the term ``weight of evidence'' does not
appear in section 110(a)(2)(D) or elsewhere in the CAA, courts have
recognized EPA's reliance on such an analytical approach where
reasonable.\20\ As described above, EPA's guidance issued for the 1997
8-hour ozone NAAQS, the Agency specifically recommended types of
information that states might wish to rely upon to evaluate the
presence of, and extent of, instate transport for this purpose. EPA
believes that a weight of evidence approach that properly considers
appropriate evidence is sufficient to make a valid determination, as in
this case.
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\20\ See, e.g., BCCA v. EPA, 355 F.3d 817 (5th Cir. 2003).
---------------------------------------------------------------------------
Specifically, EPA's technical analysis in the March 31, 2010,
proposed rule action underscores its reliance on implementation
policies set in the EPA 2006 Guidance: ``EPA's August 15, 2006,
guidance to states concerning section 110(a)(2)(D)(i) recommended
various methods by which states might evaluate whether or not its
emissions significantly contribute to violations of the 1997 ozone
standards in another state. Among other methods, EPA recommended
consideration of available EPA modeling conducted in conjunction with
CAIR, or in the absence of such EPA modeling, consideration of other
information such as the amount of emissions, the geographic location of
violating areas, meteorological data, or various other forms of
information that would be relevant to assessing the likelihood of
significant contribution to violations of the NAAQS in another state
[emphasis added].'' \21\ On the basis of this guidance, Colorado and
EPA chose to assess the impacts of emissions from Colorado sources on
the closest downwind nonattainment areas (St. Louis, Missouri, and
Illinois/Wisconsin counties along the southwestern shore of Lake
Michigan) through a weight of evidence approach using quantitative
information such as Colorado's distance from areas with monitors
showing violating the NAAQS, modeling results outlining wind vectors
for regional transport of ozone on high ozone days, back trajectory
analyses for the downwind nonattainment areas closest to Colorado, and
results of modeling studies for the nonattainment areas specifying the
range of wind directions along which contributing ozone transport
occurred. EPA's use of a weight of evidence analysis is by no means
unusual for the assessment of ozone impacts through long range
transport. The same analytical framework was used in the 1998
NOX SIP Call, as indicated under Section II.C., entitled
``Weight-of-Evidence Determination of Covered States.'' \22\ The
differences between the specific types of evidence used in the
NOX SIP Call and
[[Page 31314]]
in EPA's analysis for this action do not invalidate the use of the
weight-of-evidence approach.
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\21\ 75 FR 16034, March 31, 2010.
\22\ ``As discussed above, EPA applied a multi-factor approach
to identify the amounts of NOX emissions that contribute
significantly to nonattainment * * *.'' 1998 SIP Call, 63 FR 57381,
October 27, 1998.
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As for the commenter's argument that EPA ``fails to lend any
specific meaning to the phrase through its proposed approval,'' the
Agency's technical analysis described in the proposal did specify the
characteristics, including limitations, of a weight of evidence
analysis: ``[f]urthermore * * * EPA notes that no single piece of
information in the following discussion is by itself dispositive of the
issue. Instead, the total weight of all the evidence taken together
supports the conclusion that emissions from Colorado sources are
unlikely to contribute significantly to violations of the 1997 8-hour
ozone standard in any other state.'' (75 FR 16034).
Finally, as to the commenter's assertion that EPA failed to
consider ``several relevant factors'' and thus failed to conduct an
appropriate weight of evidence evaluation, EPA cannot weigh the
validity of this comment in the absence of an explanation of what these
factors might be.
Comment No. 14--The commenter also objected to EPA's proposed
approval of the Colorado submission on the grounds that EPA did not
assess the potential impacts of Colorado sources of emissions on
violations of the 1997 8-hour ozone NAAQS in Arizona (Phoenix area),
and Utah (Davis County area.)
EPA Response--EPA did not discuss or assess potential impacts of
Colorado emissions on Arizona or Utah in the proposal. EPA first notes
that, west of the Continental Divide the prevailing winds generally
move from south-westerly or westerly directions, as indicated by the
typical movement of weather systems.
Also, EPA notes that Davis County had a monitor indicating a
violation of the NAAQS in 2007, but has not since then. Thus, there are
currently no monitors in Utah with data showing violations of the 1997
8-hour ozone NAAQS and, as a consequence, there are no monitors for
which it would be appropriate to evaluate the possibility of
significant contribution to nonattainment from Colorado sources for the
1997 8-hour ozone NAAQS. In Arizona, the Maricopa 8-hour ozone
nonattainment area, which includes Phoenix, does have monitors
indicating a violation of this NAAQS. However, Phoenix lies
approximately 600 miles southwest of the Colorado DMA/NFR area, and
this area is generally upwind from Colorado sources. Emissions from
Colorado would have to be affected by strong winds from the northeast,
which are very infrequent, in order to contribute significantly to 8-
hour ozone nonattainment in the Phoenix area. The rarity of
northeasterly winds in Arizona may be gauged by images of wind roses
for Phoenix and Tucson.\23\
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\23\ Reproductions of wind roses are available for review under
Docket ID No. EPA-R08-OAR-2007-1032, and online at: http://home.pes.com/windroses/wrgifs/_6200.GIF; http://www.wrh.noaa.gov/twc/aviation/windrose_TUS.php; and http://www.wrcc.dri.edu/htmlfiles/westwinddir.html
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Comment No. 15--The commenter argued that both Colorado and EPA
relied inappropriately on a flawed ozone ``nonattainment'' SIP for the
DMA/NFR nonattainment area as a basis for the proposed approval.
According to the commenter, EPA cannot approve Colorado's section
110(a)(2)(d) submission because it relies heavily on the requirements
of the ozone nonattainment area SIP for the DMA/NFR nonattainment area.
The commenter argued that ``many'' of the provisions of the
nonattainment area SIP are themselves flawed or deficient. As examples,
the commenter outlined alleged deficiencies in the Colorado Air Quality
Control Commission's Regulation No. 7, RACT requirements for
NOX emissions, exemptions for certain source categories of
NOX emissions, and other unspecified provisions in the DMA/
NFR nonattainment area SIP.
EPA Response--EPA disagrees with the commenter's position that its
proposed approval relied heavily on the nonattainment area SIP for the
DMA/NFR area, and that as a consequence EPA cannot approve the Colorado
section 110(a)(2)(D) submission for the significant contribution
element for the 1997 8-hour ozone NAAQS. First, EPA notes that its
reliance on material from, and related to, the ``8-Hour Ozone
Attainment Plan'' was limited to considering the modeling results
indicating a quick drop in ambient ozone levels from the DMA/NFR area
to the easternmost Colorado counties. EPA did not purport to pass upon
the adequacy or approvability of each and every aspect of that
nonattainment area SIP by referring to the modeling results as a source
of relevant facts to be taken into consideration.
Second, the proposal made clear that EPA's interpretation of the
significance of this information is different from Colorado's: ``EPA
does not accept the State of Colorado Interstate Transport SIP
assessment that these results demonstrate that `the magnitude of ozone
transport from Colorado to other states is too low to significantly
contribute to nonattainment in * * * any other state with respect to
the 0.08 ppb NAAQS.' '' \24\ EPA explained its own view that the
relatively moderate ozone concentrations in eastern Colorado (compared
to the 1997 8-hour ozone NAAQS), while not excluding a potential
significant contribution from Colorado emissions to downwind
nonattainment areas, reduce the probability of its occurrence.\25\ This
is neither the key piece, nor even one of the key pieces, of evidence
upon which EPA relies for its determination that emissions from
Colorado sources do not contribute significantly to downwind
nonattainment areas. To the contrary, EPA considered a variety of
technical data and analyses of transport factors wholly independent of
and substantively stronger than the modeling results connected with the
DMA/NFR nonattainment area SIP.
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\24\ See 75 FR 16034-35, and ``State of Colorado Implementation
Plan to Meet the Requirements of Clean Air Act Section
110(a)(2)(D)(i)(I)--Interstate Transport Regarding the 1997 8-hour
Ozone Standard,'' p. 17, December 12, 2009.
\25\ 75 FR 16035.
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In addition, EPA notes that the commenter did not specify exactly
how each of the purported flaws in the Colorado nonattainment area SIP
for the DMA/NFR area could affect the reliability of the modeling
results EPA used in the proposed rule, or the weight-of-evidence
analysis that was the basis of the proposed approval of the Colorado
section 110(a)(2)(D) submission for the significant contribution
element. For example, the commenter did not explain what impact the
specific alleged defects in Regulation 7 would have on emissions, and
how any increases in emissions as a result of those defects would in
turn result in significant contribution to nonattainment in other
states. Absent more data or explanation supporting the commenter's
general concerns, EPA cannot conclude that these alleged nonattainment
SIP ``defects,'' even if EPA ultimately agrees that they are statutory
or regulatory deficiencies, result in additional emissions that have
such impacts. Given this uncertainty as to the impacts of the alleged
defects, if any, EPA does not agree that it is per se inappropriate to
consider the modeling results in the very limited way that the Agency
has done so in this action.
Furthermore, EPA does not agree with the commenter that, given the
alleged defects, EPA cannot approve the Colorado interstate transport
SIP for the significant contribution element of section
110(a)(2)(D)(i)(I) until the alleged defects are resolved. As discussed
below, the first step of the process to determine whether this
[[Page 31315]]
element is satisfied is the factual determination of whether a State's
emissions contribute significantly to nonattainment in downwind areas.
If this factual finding is in the negative, as is the case for EPA's
assessment of the contribution from emissions from Colorado, then
section 110(a)(2)(D)(i)(I) does not require any changes to a state's
provisions.
Finally, EPA does not agree that it is appropriate to address the
commenter's specific substantive comments about the merits of Rule 7 in
the context of this action on the section 110(a)(2)(D) SIP submission.
Colorado has separately submitted its ozone nonattainment SIP for the
DMA/NFR nonattainment area to the Agency, and that submission will
ultimately be the subject of another rulemaking in which EPA will
evaluate and act upon that specific SIP submission. The commenter may
resubmit its specific substantive comments on Rule 7, and any other
comments on the nonattainment SIP for the DMA/NFR area, in that later
rulemaking.
Comment No. 16--The commenter also objected to EPA's proposed
approval because ``Colorado'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 notes 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 Colorado 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 1998
NOX SIP call (63 FR 57356, October 27, 1998) 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 a State's emissions contribute significantly to nonattainment
in downwind areas. See 2005 CAIR Rule (70 FR 25162) and 1998
NOX SIP Call (63 FR 57356). If this factual finding is in
the negative, as is the case for EPA's assessment of the contribution
from emissions from Colorado, then section 110(a)(2)(D)(i)(I) does not
require any changes to a 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 a cap and trade program. 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.
Comment No. 17--The commenter noted a provision for stationary
source permitting in the Colorado SIP that the commenter argued is
inadequate to ensure that sources in Colorado will not significantly
contribute to nonattainment in other states. The commenter also argued
that Colorado does not sufficiently implement a requirement in the SIP
to ensure stationary sources do not cause a violation of the 1997 8-
hour ozone NAAQS, because Colorado guidelines do not uniformly require
ozone modeling for such sources. The commenter stated that EPA cannot
approve the Colorado interstate transport SIP unless the issues
commenter identifies are first resolved.
EPA Response--As discussed above, the first step of the process to
determine whether the ``significant contribution'' requirement is
satisfied is the factual determination of whether a State's emissions
contribute significantly to nonattainment in downwind areas. If the
factual finding is in the negative, as is the case for EPA's assessment
of the contribution from emissions from Colorado, then section
110(a)(2)(D)(i)(I) does not require any substantive changes to a
state's SIP, nor does it require EPA to determine whether a state
should require modeling in all permitting actions. As discussed above,
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. Therefore, EPA disagrees with the
comment that EPA cannot approve the Colorado interstate transport SIP
unless EPA addresses specific provisions and state guidelines for
permitting stationary sources.
Comment No. 18--The commenter argued that EPA cannot approve the
section 110(a)(2)(D) submission from Colorado because the state and EPA
did not comply with 110(l). Evidently, the commenter believes that the
section 110(a)(2)(D) submission 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
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) or that section 110(l)
requires disapproval of the SIP submission at issue here.
Section 110(l) provides in part that: ``[t]he 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 58134, 58199 (October 5, 2005); 70 FR 17029,
17033 (April 4, 2005); 70 FR 53, 57 (January 3, 2005); 70 FR 28429,
28431 (May 18, 2005).
Colorado's submission is the initial submission by the state to
address the significant contribution to
[[Page 31316]]
nonattainment element of 110(a)(2)(D)(i) for the 1997 8-hour ozone.
This submission does not revise or remove any existing emissions limit
for any NAAQS, or any other existing substantive SIP provisions
relevant to the 1997 8-hour ozone 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 is consistent
with this interpretation. In the cited action, EPA noted that ``Utah
ha[d] either removed or altered a number of stationary source
requirements,'' creating the possibility of a relaxation of SIP
requirements interfering with attainment, a possibility that is not
present here. See 74 FR 62727 (December 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 a 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. Accordingly, even assuming that section 110(l)
applies to this submission, EPA finds that approval of the submission
is consistent with the requirements of section 110(l).
III. Section 110(l)
Section 110(l) of the Clean Air Act states that a SIP revision
cannot be approved if the revision would interfere with any applicable
requirement concerning attainment and reasonable further progress
towards attainment of the NAAQS or any other applicable requirements of
the Act. In this action, EPA is approving portions of the Colorado
interstate transport SIP addressing the ``significant contribution''
requirements of section 110(a)(2)(D)(i)(I) for the 1997 8-hour ozone
NAAQS. As discussed above in EPA's response to comments, the SIP
revision that EPA is partially approving in this action does not revise
or remove any existing emissions limit for any NAAQS, or any other
existing substantive SIP provisions relevant to the 1997 8-hour ozone
NAAQS. As a result, the SIP revision does not relax any existing
requirements or alter the status quo air quality. Furthermore, EPA has
determined that the revision is consistent with all applicable Federal
requirements and will not interfere with requirements of the Act
related to administrative or procedural provisions. Therefore, the
revision does not interfere with attainment or maintenance of the NAAQS
or other applicable requirements of the Act.
IV. Final Action
EPA is partially approving the Interstate Transport SIP submitted
by the State of Colorado on June 18, 2009. Specifically, in this action
EPA is approving the portions of that SIP submission that address the
requirement of Section 110(a)(2)(D)(i)(I) that emissions from sources
in that state do not ``significantly contribute'' to violations of the
1997 8-hour ozone NAAQS in any other state. EPA has concluded that the
state's submission, and additional evidence evaluated by EPA, establish
that emissions from Colorado sources do not have such an impact on
other states for purposes of the 1997 8-hour ozone NAAQS. Therefore,
the state's SIP does not need to include additional substantive
controls to reduce emissions for purposes of section 110(a)(2)(D)(i)(I)
for these NAAQS. At a later date, EPA will act on those portions of the
Interstate Transport SIP that address the requirement of section
110(a)(2)(D)(i)(I) that emissions from the state's sources do not
``interfere with maintenance'' of the 1997 8-hour ozone NAAQS in any
other state.
V. Statutory and Executive Order Review
Under the Clean Air Act, the Administrator is required to approve a
SIP submission that complies with the provisions of the Act and
applicable Federal regulations. 42 U.S.C. 7410(k); 40 CFR 52.02(a).
Thus, in reviewing SIP submissions, EPA's role is to approve state
choices, provided that they meet the criteria of the Clean Air Act.
Accordingly, this action merely approves state law as meeting Federal
requirements and does not impose additional requirements beyond those
imposed by state law. For that reason, this action:
Is not a ``significant regulatory action'' subject to
review by the Office of Management and Budget under Executive Order
12866 (58 FR 51735, October 4, 1993);
Does not impose an information collection burden under the
provisions of the Paperwork Reduction Act (44 U.S.C. 3501 et seq.);
Is certified as not having a significant economic impact
on a substantial number of small entities under the Regulatory
Flexibility Act (5 U.S.C. 601 et seq.);
Does not contain any unfunded mandate or significantly or
uniquely affect small governments, as described in the Unfunded
Mandates Reform Act of 1995 (Pub. L. 104-4);
Does not have Federalism implications as specified in
Executive Order 13132 (64 FR 43255, August 10, 1999);
Is not an economically significant regulatory action based
on health or safety risks subject to Executive Order 13045 (62 FR
19885, April 23, 1997);
Is not a significant regulatory action subject to
Executive Order 13211 (66 FR 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 2, 2010.
[[Page 31317]]
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, Carbon
moNOXide, Incorporation by reference, Intergovernmental
relations, Lead, Nitrogen dioxide, Ozone, Particulate matter, Reporting
and recordkeeping requirements, Sulfur oxides, Volatile organic
compounds.
Authority: 42 U.S.C. 7401 et seq.
Dated: May 17, 2010.
Carol Rushin,
Deputy Regional Administrator, Region 8.
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 G--Colorado
0
2. Section 52.352 is added to subpart G to read as follows:
Sec. 52.352 Interstate transport.
Addition to the Colorado State Implementation Plan of the Colorado
Interstate Transport SIP regarding the 1997 8-Hour Ozone Standard for
the ``significant contribution'' requirement, as adopted by the
Colorado Air Quality Control Commission on December 30, 2008, State
effective January 30, 2009, and submitted by the Governor's designee on
June 18, 2009.
[FR Doc. 2010-13050 Filed 6-2-10; 8:45 am]
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