[Federal Register Volume 75, Number 145 (Thursday, July 29, 2010)]
[Proposed Rules]
[Pages 44734-44753]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2010-18645]
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ENVIRONMENTAL PROTECTION AGENCY
40 CFR Parts 52 and 81
[EPA-R09-OAR-2010-0585; FRL-9182-7]
Approval and Promulgation of Implementation Plans and Designation
of Areas for Air Quality Planning Purposes; State of Nevada;
Redesignation of Las Vegas Valley to Attainment for the Carbon Monoxide
Standard
AGENCY: Environmental Protection Agency (EPA).
ACTION: Proposed rule.
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SUMMARY: EPA is proposing to approve the State of Nevada's request to
redesignate to attainment the Las Vegas Valley nonattainment area for
the carbon monoxide national ambient air quality standard. EPA is also
proposing to approve the carbon monoxide maintenance plan and motor
vehicle emissions budgets for the area, as well as certain additional
revisions to the Nevada State implementation plan. These revisions
include the suspension of a local wintertime cleaner burning gasoline
rule, and the relaxation of a State rule governing wintertime gasoline
in Clark County. EPA's proposed approval is contingent upon receipt of
a supplemental submittal from the State of Nevada containing a
commitment to reinstate the existing vapor pressure limit in the State
wintertime gasoline rule, if necessary, and thereby to implement the
related contingency measure in the maintenance plan.
DATES: Comments must be received on or before August 30, 2010.
ADDRESSES: Submit comments, identified by docket number EPA-R09-OAR-
2010-0585, by one of the following methods:
1. Federal eRulemaking Portal: http://www.regulations.gov. Follow
the on-line instructions for submitting comments.
2. E-mail: [email protected].
3. Mail or deliver: Karina O'Connor (AIR-2), U.S. Environmental
Protection Agency Region IX, 75 Hawthorne Street, San Francisco, CA
94105-3901.
Instructions: Direct your comments to Docket ID No. EPA-R09-OAR-
2010-0585. EPA's policy is that all comments received will be included
in the public docket without change and may be made available online at
http://www.regulations.gov, including any personal information
provided, unless the comment includes information claimed to be
Confidential Business Information (CBI) or other information whose
disclosure is restricted by statute. Do not submit information that you
consider to be CBI or otherwise protected through http://www.regulations.gov or e-mail. The http://www.regulations.gov Web site
is an ``anonymous access'' system, which means that EPA will not know
your identity or contact information unless you provide it in the body
of your comment. If you send e-mail directly to EPA, without going
through http://www.regulations.gov, your e-mail address will be
automatically captured and included as part of the comment that is
placed in the public docket and made available on the Internet. If you
[[Page 44735]]
submit an electronic comment, EPA recommends that you include your name
and other contact information in the body of the comment and with any
disk or CD-ROM you submit. If EPA cannot read your comment due to
technical difficulties and cannot contact you for clarification, EPA
may not be able to consider your comment. Electronic files should avoid
the use of special characters, any form of encryption, and be free of
any defects or viruses.
Docket: All documents in the docket are listed in the http://www.regulations.gov index. Although listed in the index, some
information is not publicly available, e.g., CBI or other information
whose disclosure is restricted by statute. Certain other information,
such as copyrighted material, will be publicly available only in hard
copy form. Publicly available docket materials are available either
electronically in http://www.regulations.gov or in hard copy at the
Office of Air Planning, Environmental Protection Agency (EPA), Region
IX, 75 Hawthorne Street, San Francisco, California. To inspect the hard
copy materials, please schedule an appointment during normal business
hours with the contact listed in the FOR FURTHER INFORMATION CONTACT
section.
FOR FURTHER INFORMATION CONTACT: Karina O'Connor, EPA Region IX, (775)
833-1276, [email protected].
SUPPLEMENTARY INFORMATION: Throughout this document, the terms ``we,''
``us,'' and ``our'' refer to EPA. This supplementary information is
organized as follows:
Table of Contents
I. Summary of Today's Proposed Action
II. Background
III. Procedural Requirements for Adoption and Submittal of SIP
Revisions
IV. Substantive Requirements for Redesignation
V. Evaluation of the State's Redesignation Request for Las Vegas
Valley
A. Determination That the Area Has Attained the Applicable NAAQS
B. The Area Must Have a Fully Approved SIP Meeting Requirements
Applicable for Purposes of Redesignation Under Section 110 and Part
D
1. Basic SIP Requirements Under CAA Section 110
2. Part D Requirements
a. Introduction
b. RFP and Attainment Demonstration
c. Reasonable Available Control Measures/Control Technology
d. Emission Inventory
e. Permits for New and Modified Major Stationary Sources
f. Contingency Provisions
g. Conformity Requirements
h. VMT Forecasts and Annual Updates
i. Vehicle Inspection and Maintenance Program
j. TCMs To Offset VMT-Related Emissions Increases and To Provide
for RFP
k. Oxygenated Gasoline Program
l. Clean Data Policy and CO Milestone Requirement
3. Conclusion With Respect to Section 110 and Part D
Requirements
C. The Area Must Show the Improvement in Air Quality Is Due to
Permanent and Enforceable Emissions Reductions
D. The Area Must Have a Fully Approved Maintenance Plan Under
CAA Section 175A
1. Attainment Inventory
2. Maintenance Demonstration
3. Monitoring Network
4. Verification of Continued Attainment
5. Contingency Provisions
6. Subsequent Maintenance Plan Revisions
7. Motor Vehicle Emissions Budgets
8. Conclusion
VI. Evaluation of Suspended or Relaxed Wintertime Gasoline
Specifications
VII. Proposed Action and Request for Comment
VIII. Statutory and Executive Order Reviews
I. Summary of Today's Proposed Action
EPA is proposing to approve the Nevada Division of Environmental
Protection's (NDEP's) request to redesignate to attainment the Las
Vegas Valley \1\ carbon monoxide (CO) nonattainment area located within
Clark County, Nevada, and related revisions to the Nevada State
implementation plan (SIP). The specific SIP revision submittals that we
are proposing to approve are listed in the following table:
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\1\ Specifically, the Las Vegas Valley CO nonattainment area is
defined by reference to State hydrographic area 212. See 40
CFR 81.329. The Las Vegas Valley encompasses roughly 1,500 square
miles within Clark County and includes the cities of Las Vegas,
North Las Vegas, and Henderson. Roughly two million people reside in
Clark County, mostly within Las Vegas Valley. NDEP is the State
agency under State law that is responsible for SIP matters for the
State of Nevada. Within Clark County, the Clark County Board of
Commissioners, acting through the Department of Air Quality and
Environmental Management (DAQEM), is empowered under State law to
develop air quality plans and to regulate stationary sources within
the county with the exception of certain types of power plants,
which lie exclusively within the jurisdiction of NDEP.
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State of Nevada
Plan or Rule Adoption date(s) submittal date(s)
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Carbon Monoxide Adopted by the Clark Submitted by NDEP by
Redesignation Request and County Board of letter dated
Maintenance Plan, Las Vegas Commissioners on September 18, 2008.
Valley Nonattainment Area, September 2, 2008.
Clark County, Nevada
(September 2008).
Clark County Air Quality Adopted by the Clark Submitted by NDEP by
Regulations, Section 54 County Board of letter dated March
(``Cleaner Burning Gasoline Commissioners on 26, 2010.
(CBG): Wintertime September 15, 2009,
Program'') (Suspended). effective September
29, 2010.
Nevada Administrative Code Adopted by the Submitted by NDEP by
(NAC) section 590.065 Nevada Board of letter dated March
(amended). Agriculture on 26, 2010.
December 9, 2010,
effective January
28, 2010.
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Specifically, we are proposing to approve NDEP's maintenance plan
submittal dated September 18, 2008 titled Carbon Monoxide Redesignation
Request and Maintenance Plan, Las Vegas Valley Nonattainment Area,
Clark County, Nevada (September 2008) (``Las Vegas Valley CO
Maintenance Plan'' or ``Maintenance Plan'') \2\ as a revision to the
Nevada SIP, and to approve NDEP's request to redesignate Las Vegas
Valley to attainment for the CO NAAQS. We are proposing to approve the
Las Vegas Valley CO Maintenance Plan because we find that it meets all
requirements for such plans in section 175A under the Clean Air Act
(``Act'' or CAA), and we are proposing to approve NDEP's redesignation
request for Las Vegas Valley from nonattainment to attainment because
we believe that the area has met all of the criteria for redesignation
under CAA section 107(d)(3)(E). The Las Vegas Valley CO Maintenance
Plan includes CO motor vehicle emissions budgets (MVEBs) for years
2008, 2010, and 2020,
[[Page 44736]]
and we are proposing to approve these budgets for the purposes of
transportation conformity based on our conclusion that they meet the
criteria for such budgets in 40 CFR 93.118(e). Final approval of the
redesignation request and maintenance plan would change the legal
description of the Las Vegas Valley CO nonattainment area in 40 CFR
part 81 from nonattainment to attainment, and would make Federally
enforceable the commitments and contingency provisions contained in the
maintenance plan.
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\2\ The Las Vegas Valley CO Maintenance Plan consists of the
main body of the plan and three appendices: Appendix A (``Wintertime
Gasoline Fuel Specification Study''), Appendix B (Technical Support
Document, Carbon Monoxide Modeling for the Clark County Maintenance
Plan''), Appendix C (``Documentation of the Public Review
Process'').
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In connection with the CO Maintenance Plan, Clark County and the
State of Nevada have decided to suspend or relax two gasoline-related
regulations that formed part of the control strategy that has provided
for attainment of the CO standard in Las Vegas Valley but that they
believe are not needed for the purposes of maintaining the CO standard
now that the CO standard has been attained. These are Clark County Air
Quality Regulations (AQR) Section 54 (``Cleaner Burning Gasoline:
Wintertime Program'') (herein, referred to as the ``CBG Rule''), which
establishes certain wintertime gasoline specifications related to
sulfur and aromatic hydrocarbons (``aromatics''), and Nevada
Administrative Code (NAC) section 590.065 (herein referred to as the
``Low RVP Rule''), which establishes a low Reid vapor pressure (RVP)
specification for gasoline sold during the late fall and winter months
in Clark County. We are proposing to approve the suspension of Clark
County's CBG Rule and the relaxation of the State's Low RVP Rule
because we conclude, in accordance with CAA section 110(l), that doing
so would not interfere with attainment or maintenance of any of the
NAAQS or any applicable requirement of the Clean Air Act.\3\
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\3\ We are not including subsection (7) of amended NAC 590.065
in our proposed approval because the limits in subsection (7) of the
amended rule are unrelated to the vapor pressure requirement and
associated CO emissions reductions, and are severable from the rest
of the rule.
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The Las Vegas Valley CO Maintenance Plan includes reinstatement of
the CBG Rule and the Low RVP Rule as contingency measures, as required
under CAA section 175A(d). However, while Clark County, through
adoption of the maintenance plan, has committed to reinstatement of the
CBG Rule in accordance with the contingency provisions of the plan, the
Nevada State Department of Agriculture, which is responsible for the
Low RVP Rule, has not yet made a similar commitment with respect to the
Low RVP Rule. Thus, our approval of the Maintenance Plan and
redesignation request is contingent upon the submittal, and EPA
approval, of such a commitment as a revision to the Nevada SIP.\4\
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\4\ On July 12, 2010, the Nevada Department of Agriculture
initiated a 30-day comment period to solicit comment (or request a
public hearing) on the draft commitment regarding implementation of
the contingency measure in the Maintenance Plan related to
reinstatement of the Low RVP Rule. The Department's notice of intent
to solicit public comment, which includes the commitment language,
has been placed in the docket for this rulemaking. We have reviewed
the language of the Department's draft commitment and expect to
approve it if it is ultimately submitted to us without significant
modification.
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II. Background
Carbon monoxide (CO) is a colorless, odorless gas emitted in
combustion processes. In most areas where elevated CO levels are found,
CO comes primarily from tailpipe emissions of cars and trucks. Exposure
to elevated CO levels is associated with impairment of visual
perception, work capacity, manual dexterity and learning ability, and
with illness and death for those who already suffer from cardiovascular
disease, particularly angina or peripheral vascular disease.
On April 30, 1971 (see 36 FR 8186), pursuant to section 109 of the
Act, as amended in 1970, EPA promulgated the original national ambient
air quality standards (NAAQS) for several pervasive air pollutants,
including CO. NAAQS represent concentration levels the attainment and
maintenance of which, allowing for an adequate margin of safety, EPA
has determined to be requisite to protect public health (``primary''
NAAQS) and welfare (``secondary'' NAAQS). The primary (i.e., health-
based) NAAQS for CO is 9 parts per million (ppm) averaged over an 8-
hour period, and 35 ppm averaged over 1 hour, neither to be exceeded
more than once per year. In our 1971 rulemaking, we established
identical primary and secondary NAAQS for CO but later revoked the
secondary (welfare) NAAQS for CO. See 50 FR 37484 (September 13, 1985).
The (primary) CO NAAQS established by EPA in 1971, remain in effect
today. See 40 CFR 50.8 (``National primary ambient air quality
standards for carbon monoxide'').
Under section 110 of the Act, each State is required to adopt and
submit to EPA a plan that provides for the implementation, maintenance,
and enforcement of the NAAQS within each State. These plans are
referred to as ``State implementation plans'' or ``SIPs.'' Under the
Clean Air Act, as amended in 1970, SIPs were required to provide for
attainment of the NAAQS within 3 years after EPA approval of the plan.
However, many areas of the country did not attain the NAAQS within the
statutory period.
In response, Congress amended the Act in 1977 to establish a new
approach, based on area designations, for attaining the NAAQS, and on
March 3, 1978 (43 FR 8962), we promulgated attainment status
designations for all areas within each of the States. In the 1978
rulemaking, we designated Las Vegas Valley as a ``nonattainment'' area
for the CO NAAQS based on monitored violations of the 8-hour CO
NAAQS.\5\ See 43 FR 8962, at 9013 (March 3, 1978).
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\5\ Thus, the CO plans previously approved by EPA for Las Vegas
Valley assume that the 8-hour CO standard, rather than the 1-hour CO
standard, is the controlling standard. That is, attainment of the
former necessarily means attainment of the latter. The same holds
true in the submitted Las Vegas Valley CO Maintenance Plan, which
includes a maintenance demonstration for the 8-hour CO standard, not
the 1-hour CO standard.
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The Clean Air Act, as amended in 1977, required States to revise
their SIPs by preparing, adopting and submitting attainment plans (for
EPA approval) that set forth a strategy to achieve the NAAQS in
designated nonattainment areas. The original statutory deadline for
attainment under the 1977 Amended Act was 1982, but extensions to 1987
were allowed if certain SIP requirements were met. In response, Clark
County and the State of Nevada adopted and implemented various air
quality plans and programs, including a vehicle inspection and
maintenance (I/M) program, to reduce CO levels in Las Vegas Valley. EPA
approved these plans and programs at various times as revisions to the
Nevada State implementation plan (SIP). See 46 FR 21758 (April 14,
1981); 47 FR 15790 (April 13, 1982); 49 FR 44208 (November 5, 1984).
Despite these programs, Las Vegas Valley did not attain the CO NAAQS by
the then-applicable 1987 attainment date.
The CAA was significantly amended by Congress in 1990 to establish
new attainment dates and planning and control requirements for areas,
like Las Vegas Valley, that had failed to attain the NAAQS under the
1977 Amendments. Under the 1990 Amended Act, Las Vegas Valley was
initially classified as a ``moderate'' nonattainment area for CO (based
on a design value of 14.4 ppm) but was subsequently reclassified as a
``serious'' CO nonattainment area after having failed to attain the
standard by the applicable attainment date (i.e., December 31, 1995)
for moderate areas.
[[Page 44737]]
See 62 FR 51604 (October 2, 1997). The Las Vegas Valley area was then
subject to the applicable attainment deadline for ``serious'' CO
nonattainment areas (i.e., December 31, 2000). See CAA section
186(a)(1).
In response to nonattainment classifications and related CAA
requirements, Clark County and the State of Nevada adopted and
implemented new air quality plans and programs, including a ``serious''
area attainment plan titled Carbon Monoxide State Implementation Plan,
Las Vegas Valley Nonattainment Area, Clark County, Nevada (August 2000)
(``2000 Las Vegas Valley CO Plan'' or ``2000 CO Plan''). We approved
the 2000 Las Vegas Valley CO Plan in 2004. See 69 FR 56351 (September
21, 2004).
In connection with the 2000 Las Vegas Valley CO Plan, we approved,
among other plan elements, Clark County AQR Section 54 (``Cleaner
Burning Gasoline (CBG): Wintertime Program'') (i.e., the CBG Rule)
(originally adopted by Clark County in 1999), the State's alternate
``low'' enhanced vehicle I/M program for Las Vegas Valley and Boulder
City, the State's regulation establishing a low RVP wintertime gasoline
specification for Clark County (i.e., the Low RVP Rule) (originally
adopted by the State Board of Agriculture in 1995), the State's
alternative fuels for government fleets program, the Regional
Transportation Commission of Southern Nevada's (RTC's) Transportation
Control Measures/Transportation Demand Management (TCM/TDM) program,
and an amended version of previously approved Clark County AQR Section
53 (``Oxygenated Gasoline Program'') (originally adopted by Clark
County in 1991). The 2000 Las Vegas Valley CO Plan identifies the CBG
Rule, I/M program, Low RVP Rule, and the oxygenated gasoline program,
along with the Federal Motor Vehicle Control Program (FMVCP), as the
primary control measures providing for attainment of the CO NAAQS in
Las Vegas Valley by the applicable attainment date (2000). In 2004, we
also approved the 2000 CO Plan's motor vehicle emissions budgets
(MVEBs) for years 2000, 2010 and 2020.\6\
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\6\ While important for the purposes of attaining the CO
standard by the applicable attainment date (2000), the Maintenance
Plan shows that the Low RVP Rule and the CBG Rule are no longer
necessary for the purposes of maintaining the CO standard. The
consistent, but more gradual, emissions reduction benefits of the
FMVCP and natural vehicle turnover (i.e., replacement of older more
polluting motor vehicles with newer cleaner vehicles) allow for the
relaxation of these fuel rules consistent with continued maintenance
of the CO standard.
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In 2005, EPA determined that the Las Vegas Valley had attained the
CO NAAQS by its applicable attainment deadline of December 31, 2000 [70
FR 31353 (June 1, 2005)], and had continued to attain through 2003 [70
FR 3174, at 3177 (January 21, 2005)]. This attainment determination did
not constitute redesignation to attainment, however, because it did not
include consideration or approval of the additional requirements for
redesignation set forth in CAA section 107(d)(3)(E), e.g., a
maintenance plan satisfying CAA section 175A.
In 2006, EPA approved a Las Vegas Valley CO plan titled Carbon
Monoxide State Implementation Plan Revision, Las Vegas Valley
Nonattainment Area, Clark County, Nevada (October 2005) (``2005 Las
Vegas Valley CO Plan'' or ``2005 CO Plan''), which amended the
emissions inventories, attainment demonstration, and related MVEBs from
the 2000 Las Vegas Valley CO Plan in response to changes in the EPA-
approved motor vehicle emission factor model and higher-than-forecast
increases in population growth in Las Vegas Valley. See 71 FR 44587
(August 7, 2006).
EPA today is proposing to approve the State's request to
redesignate the Las Vegas Valley to attainment for the CO NAAQS, and to
approve the Las Vegas Valley CO Maintenance Plan. We are also proposing
approval of the suspension or relaxation of two specific control
measures that had previously been approved into the SIP, but that Clark
County has shown are no longer needed to maintain the CO NAAQS in Las
Vegas Valley: the County's CBG Rule and the State's Low RVP Rule. Our
evaluation of the submittals and the redesignation request is provided
in the following sections of this document.
III. Procedural Requirements for Adoption and Submittal of SIP
Revisions
Section 110(l) of the Act requires States to provide reasonable
notice and public hearing prior to adoption of SIP revisions. In this
action, we are proposing action on the following SIP revisions: The Las
Vegas Valley CO Maintenance Plan, submitted by NDEP on September 18,
2008; and the suspended or relaxed wintertime gasoline regulations,
submitted by NDEP on March 26, 2010.
Both of the SIP revision submittals cited above contain evidence
that reasonable notice of a public hearing was provided to the public
and that a public hearing was conducted prior to adoption.
Specifically, notice of the availability of, and opening of a 30-day
comment period on, the draft CO maintenance plan was published on
several dates in a newspaper of general circulation within the Las
Vegas area beginning on May 11, 2008. The Clark County Board of
Commissioners adopted the Las Vegas Valley CO Maintenance Plan by
resolution on September 2, 2008 at the close of the public hearing.
Appendix C to the plan documents the public review process used by the
county to adopt the plan. Following adoption, Clark County DAQEM
forwarded the plan to NDEP, the Governor of Nevada's designee for SIP
matters, and NDEP then submitted the plan as a revision to the Nevada
SIP to EPA for approval.
NDEP's March 26, 2010 SIP submittal documents the public review
process used by the Clark County Board of Commissioners in suspending
Section 54 (i.e., the CBG Rule) and by the State Board of Agriculture
in relaxing the wintertime gasoline vapor pressure requirement.
Specifically, NDEP's March 26, 2010 submittal documents the Clark
County Board of Commissioners' September 15, 2009 public hearing on,
and subsequent adoption of, Ordinance No. 3809 suspending the CBG Rule,
effective September 29, 2009. Notice of Clark County DAQEM's workshop
to discuss suspension of the CBG Rule was published on several dates in
a newspaper of general circulation within the Las Vegas area beginning
on May 17, 2009.
The March 26, 2010 SIP revision submittal also documents the State
Board of Agriculture's December 9, 2009 public hearing on, and
subsequent adoption of, amendments to NAC section 590.065 (LCB File No.
R111-08), effective January 28, 2010, including the relaxation of the
RVP wintertime gasoline limit in Clark County from 9.0 to 13.5 pounds
per square inch (psi). This action on the part of the Board of
Agriculture was preceded by publication on September 16, 2009 by the
Nevada Department of Agriculture of a notice of a workshop to be held
on October 13, 2009 to solicit comments on amendments to NAC section
590.065, and by publication on November 4, 2009 of a notice of intent
to act upon a regulation.
Based on the documentation submitted with the two SIP submittals
and summarized above, we find that both SIP revisions cited above
satisfy the procedural requirements of section 110(l) of the Act for
revising SIPs.
[[Page 44738]]
IV. Substantive Requirements for Redesignation
The CAA establishes the requirements for redesignation of a
nonattainment area to attainment. Specifically, section 107(d)(3)(E)
allows for redesignation provided that the following criteria are met:
(1) EPA determines that the area has attained the applicable NAAQS; (2)
EPA has fully approved the applicable implementation plan for the area
under section 110(k); (3) EPA determines that the improvement in air
quality is due to permanent and enforceable reductions in emissions
resulting from implementation of the applicable SIP, applicable Federal
air pollution control regulations, and other permanent and enforceable
reductions; (4) EPA has fully approved a maintenance plan for the area
as meeting the requirements of CAA section 175A; and (5) the State
containing such area has met all requirements applicable to the area
under section 110 and part D of the CAA. Section 110 identifies a
comprehensive list of elements that SIPs must include, including plan
revisions meeting the requirements of part D (i.e., CAA section 171
through section 193), and part D establishes the SIP requirements for
nonattainment areas. Part D is divided into six subparts; the CO-
specific nonattainment SIP requirements are found in part D, subpart 3,
which includes CAA sections 186 and 187.
EPA provided guidance on redesignations in a document entitled,
``State Implementation Plans; General Preamble for the Implementation
of Title I of the Clean Air Act Amendments of 1990,'' published in the
Federal Register on April 16, 1992 (57 FR 13498), and supplemented on
April 28, 1992 (57 FR 18070) (referred to herein as the ``General
Preamble''). Another relevant EPA guidance document includes
``Procedures for Processing Requests to Redesignate Areas to
Attainment,'' Memorandum from John Calcagni, Director, Air Quality
Management Division, EPA Office of Air Quality Planning and Standards,
September 4, 1992 (referred to herein as the ``Calcagni memo'').
For the reasons set forth below in section V of this document, we
propose to approve NDEP's request for redesignation of the Las Vegas
Valley nonattainment area to attainment for the CO NAAQS based on our
conclusion that all of the criteria under CAA section 107(d)(3)(E) have
been satisfied. For the reasons set forth in section V.D.5 of this
document, our proposed approval is contingent upon NDEP's submission of
a commitment by the Nevada Department of Agriculture to reinstate the
Low RVP Rule if necessary to address future violations of the CO NAAQS
in Las Vegas Valley and thereby implement the related contingency
measure in the Maintenance Plan.
V. Evaluation of the State's Redesignation Request for Las Vegas Valley
A. Determination That the Area Has Attained the Applicable NAAQS
CAA section 107(d)(3)(E) requires that we determine that the area
has attained the NAAQS. EPA makes the determination as to whether an
area's air quality is meeting the CO NAAQS based upon air quality data
gathered at CO monitoring sites in the nonattainment area which have
been entered into the Air Quality System (AQS) database. This data is
reviewed to determine the area's air quality status in accordance with
40 CFR 50.8; EPA policy guidance as stated in a memorandum from William
G. Laxton, Director Technical Support Division, entitled ``Ozone and
Carbon Monoxide Design Value Calculations,'' dated June 18, 1990; and
EPA's General Preamble at 57 FR 13535.
The 8-hour and 1-hour CO design values are used to determine
attainment of CO areas, and the design values are determined by
reviewing 8 quarters of data, or a total of two complete calendar years
of data for an area. The 8-hour design value is computed by first
finding the maximum and second maximum (non-overlapping) 8-hour values
at each monitoring site for each year of the two calendar years prior
to and including the attainment date. Then the higher of the ``second
high'' values is used as the design value for the monitoring site, and
the highest design value among the various CO monitoring sites
represents the CO design value for the area.
The CO NAAQS requires that not more than one 8-hour average per
year equals or exceeds 9.5 ppm (values below 9.5 are rounded down to 9
and are not considered exceedances). If an area has a design value that
is equal to or greater than 9.5 ppm, this means that there was a
monitoring site where the second highest (non-overlapping) 8-hour
average was measured to be equal to or greater than 9.5 ppm in at least
one of the two years being reviewed to determine attainment for the
area. This indicates that there were at least two values above the
NAAQS during one year at that site and thus the NAAQS for CO was not
met. Conversely, an 8-hour design value of less than 9.5 ppm indicates
that the area has attained the CO NAAQS. The 1-hour CO design value is
computed in the same manner. An area attains the one-hour CO NAAQS if
the 1-hour design value is less than 35.5 ppm.
On June 1, 2005 (70 FR 31353), we determined that the Las Vegas
Valley ``serious'' CO nonattainment area had attained the CO NAAQS by
the applicable attainment date (2000) based on complete quality-assured
data showing a design value of the area (from Sunrise Acres station)
for 1999-2000 of 8.2 ppm, eight-hour average, and 10.2 ppm, one-hour
average. (The corresponding NAAQS are 9 ppm, eight-hour average, and 35
ppm, one-hour average.) We also found that Las Vegas Valley had
continued to attain the standard through year 2003. As part of that
determination, we reviewed the ambient CO monitoring network operated
by Clark County DAQEM and found that it met or exceeded our
requirements. See 70 FR 3174 (January 21, 2005).
In our proposed determination that the area had attained by its
attainment deadline (2000) (70 FR 3174, January 21, 2005), we described
Clark County's CO monitoring network at that time as including 7 SLAMS
sites, 4 NAMS sites, and 4 special purpose sites.\7\ Since our 2005
finding of attainment, Clark County has closed a number of CO
monitoring sites. There are now five CO monitoring sites in Las Vegas
Valley: Winterwood, East Sahara, Sunrise Acres, Orr School and J.D.
Smith. All of the monitoring sites are SLAMS, and the J.D. Smith site
is also a NAMS site. All sites have population exposure as their
monitoring objective except Sunrise Acres, which has ``highest
concentration'' as its monitoring objective.
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\7\ EPA has established ambient air quality monitoring
requirements and standards for State and Local Air Monitoring
Stations (SLAMS) and for National Air Monitoring Stations (NAMS).
These requirements and standards provide for operating schedules,
data quality assurance, and for the design and siting of CO
samplers.
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While the number of CO monitoring stations has been reduced, we
conclude in our Technical Systems Audit Report (February 2010) that the
network currently meets or exceeds the requirements for the minimum
number of CO monitoring sites. Moreover, we note that the Sunrise Acres
monitoring station, which is the site at which the highest CO
concentrations have historically been recorded, remains among those
that continue to be operated by Clark County DAQEM.
For the purposes of this proposed rule, we reviewed complete,
quality-assured monitoring data that are
[[Page 44739]]
uploaded to our Air Quality System (AQS) database. We found that no
exceedances of the CO NAAQS were recorded in Las Vegas Valley during
the entire period from 2004-2009. During this period, the highest 8-
hour CO concentrations were 60% of the NAAQS or less at all of the
monitoring stations. Table 1 summarizes the 2nd highest 8-hour and 1-
hour average CO concentrations at the various monitoring stations
during the most recent two-year period. As shown in the table, the 8-
hour design value for the area based on 2008-2009 data is 3.7 ppm,
eight-hour average, and 4.7 ppm, 1-hour average, both of which are well
below the corresponding NAAQS of 9 and 35 ppm, respectively.
Preliminary data available for 2010 show that there continue to be no
exceedances of the CO NAAQS in the area.
Table 1--Summary of Las Vegas Valley CO Monitoring Data, 2008-2009
--------------------------------------------------------------------------------------------------------------------------------------------------------
2nd highest 8-hour concentration (ppm) 2nd highest 1-hour concentration (ppm)
Monitoring site name -----------------------------------------------------------------------------------------------
2008 2009 Design value 2008 2009 Design value
--------------------------------------------------------------------------------------------------------------------------------------------------------
Winterwood.............................................. 2.9 2.8 2.9 3.8 3.7 3.8
East Sahara............................................. 3.7 3.1 3.7 4.7 4.2 4.7
Sunrise Acres........................................... 3.5 2.8 3.5 4.2 4.7 4.7
Orr School.............................................. 2.6 2.6 2.6 3.2 3.2 3.2
J.D. Smith.............................................. 2.5 2.4 2.5 3.6 3.2 3.6
-----------------------------------------------------------------------------------------------
Area Design Value....................................... 8-Hour CO Design Value = 3.7 ppm (East Sahara)
1-Hour CO Design Value = 4.7 ppm (East Sahara
and Sunrise Acres)
-----------------------------------------------------------------------------------------------
CO NAAQS................................................ 9 ppm
35 ppm
--------------------------------------------------------------------------------------------------------------------------------------------------------
Based on the AQS data presented above and the positive assessment
of the Clark County DAQEM ambient CO monitoring network that we made in
February 2010, we propose to determine that Las Vegas Valley has
attained the CO NAAQS, and thus meets the criterion for redesignation
set forth in section 107(d)(3)(E)(i).
B. The Area Must Have a Fully Approved SIP Meeting Requirements
Applicable for Purposes of Redesignation Under Section 110 and Part D
Section 107(d)(3)(E)(ii) and (v) require EPA to determine that the
area has a fully approved applicable SIP under section 110(k) that
meets all applicable requirements under section 110 and part D for the
purposes of redesignation.
1. Basic SIP Requirements Under CAA Section 110
Section 110(a)(2) sets forth the general elements that a SIP must
contain in order to be fully approved. Although section 110(a)(2) was
amended in 1990, a number of the requirements did not change in
substance, and therefore, EPA believes that the pre-amendment EPA-
approved SIP met these requirements in Las Vegas Valley with respect to
CO. As to those requirements that were amended, (see 57 FR 27936 and
27939, June 23, 1992), many are duplicative of other requirements of
the Act. EPA has analyzed the Nevada SIP and determined that it is
consistent with the requirements of amended section 110(a)(2). The Las
Vegas Valley portion of the approved Nevada SIP contains enforceable
emission limitations; requires monitoring, compiling and analyzing of
ambient air quality data; requires preconstruction review of new or
modified stationary sources; provides for adequate funding, staff, and
associated resources necessary to implement its requirements; and
provides the necessary assurances that the State maintains
responsibility for ensuring that the CAA requirements are satisfied in
the event that Clark County is unable to meet its CAA obligations.\8\
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\8\ The applicable SIP for NDEP and Clark County may be found at
http://yosemite.epa.gov/r9/r9sips.nsf/allsips?readform&state=Nevada.
We note that SIPs must be fully approved only with respect to
applicable requirements for purposes of redesignation in accordance
with section 107(d)(3)(E)(ii). Thus, for example, CAA section
110(a)(2)(D) requires that SIPs contain certain measures to prevent
sources in a State from significantly contributing to air quality
problems in another State. However, the section 110(a)(2)(D)
requirements for a State are not linked with a particular
nonattainment area's designation and classification in that State.
EPA believes that the requirements linked with a particular
nonattainment area's designation and classification are the relevant
measures to evaluate in reviewing a redesignation request. The
transport SIP submittal requirements, where applicable, continue to
apply to a State regardless of the designation of any one particular
area in the State.
Thus, we do not believe that these requirements should be
construed to be applicable requirements for purposes of
redesignation. In addition, EPA believes that the other section 110
elements not connected with nonattainment plan submissions and not
linked with an area's attainment status are not applicable
requirements for purposes of redesignation. The State will still be
subject to these requirements after Las Vegas Valley is
redesignated. The section 110 and part D requirements, which are
linked with a particular area's designation and classification, are
the relevant measures to evaluate in reviewing a redesignation
request. This policy is consistent with EPA's existing policy on
applicability of conformity (i.e., for redesignations) and
oxygenated fuels requirement. See Reading, Pennsylvania, proposed
and final rulemakings 61 FR 53174-53176 (October 10, 1996), 62 FR
24816 (May 7, 1997); Cleveland-Akron-Lorain, Ohio, final rulemaking
61 FR 20458 (May 7, 1996); and Tampa, Florida, final rulemaking 60
FR 62748 (December 7, 1995). See also the discussion of this issue
in the Cincinnati redesignation 65 FR 37890 (June 19, 2000), in the
Pittsburgh redesignation 66 FR 50399 (October 19, 2001), and in the
Los Angeles redesignation 72 FR 6986 (February 14, 2007) and 72 FR
26718 (May 11, 2007). EPA believes that section 110 elements not
linked to the area's nonattainment status are not applicable for
purposes of redesignation.
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On numerous occasions over the past 38 years, NDEP has submitted
and we have approved provisions addressing the basic CAA section 110
provisions. There are no outstanding or disapproved applicable SIP
submittals with respect to the Las Vegas Valley portion of the SIP. We
propose to conclude that NDEP and Clark County have met all SIP
requirements for Las Vegas Valley applicable for purposes of
redesignation under section 110 of the CAA (General SIP Requirements).
With the exception discussed below in Section V.B.2.l of this document,
the SIP for Las Vegas Valley also has been approved as meeting
applicable requirements under part D of Title I of the CAA.
2. Part D Requirements
a. Introduction
The requirements that apply under part D (of Title I) of the Act to
``serious'' CO nonattainment areas are set forth in sections 172, 176,
187, and 211. In the General Preamble, we have issued guidance
describing how we will review SIPs and SIP revisions submitted under
part D (of Title I) of the Act, including
[[Page 44740]]
those containing ``serious'' CO nonattainment area SIP provisions. In
the following paragraphs, we explain how the State has met the
applicable SIP revision requirements under part D for the Las Vegas
Valley CO nonattainment area or where, in the case of certain
requirements, how the requirement does not apply because Las Vegas
Valley has attained the CO standard.\9\
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\9\ In addition, we note that the State has not sought to
exercise the options available under CAA sections 172(c)(4)
(identification and quantification of certain emissions increases)
and 172(c)(8) (equivalent techniques). Thus, these provisions are
not relevant to the request for redesignation for the Las Vegas
Valley CO nonattainment area.
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b. RFP and Attainment Demonstration
Under CAA sections 172(c)(2) and 187(a)(7), with respect to a
serious CO nonattainment area, States are required to a submit a SIP
revision that provides, and a demonstration that the plan as revised
will provide, for attainment of the CO NAAQS by the applicable
attainment date and provisions for such specific annual emission
reductions as are necessary to attain the standard by that date. In
2004, in approving the 2000 Las Vegas Valley CO Plan, we approved the
area's RFP demonstration under sections 172(c)(2) and 187(a)(7) and
attainment demonstration under section 187(a)(7). See 69 FR 56351, at
56353 (September 21, 2004). Thus, the area has met the SIP requirements
under CAA sections 172(c)(2) and 187(a)(7).
c. Reasonable Available Control Measures/Control Technology
Section 172(c)(1) of the Act requires States to submit a SIP
revision for nonattainment areas that provide for the implementation of
all reasonably available control measures (RACM) as expeditiously as
practicable (including such reductions in emissions from existing
sources in the area as may be obtained through the adoption, at a
minimum, of reasonably available control technology (RACT)) and shall
provide for attainment of the NAAQS. RACM is a more general term that
can refer to stationary, area or mobile sources while RACT is a term
that refers to stationary sources.
Attainment of the CO NAAQS in Las Vegas Valley relied upon the
Federal Motor Vehicle Control Program and five State or local control
measures: The State's vehicle I/M program, the State's Low RVP Rule,
Clark County's rules (AQR sections 53 (i.e., wintertime oxygenated
gasoline rule) and the CBG Rule) establishing wintertime gasoline
requirements related to oxygen content, sulfur content, and aromatics,
and to a lesser degree, the State's Alternative Fuels for Government
Fleets program, and RTC's TCM/TDM program. We have previously approved
all of these State and local control measures into the Nevada SIP.
Based on our 2005 determination that Las Vegas Valley had attained the
CO NAAQS by the applicable attainment date (2000), we believe that no
additional measures need be submitted to fulfill the RACM/RACT
requirement of CAA section 172(c)(1) in the Las Vegas Valley CO
nonattainment area.
d. Emissions Inventory
Sections 172(c)(3) and 187(a)(1) of the Act require States to
submit a comprehensive, accurate, current inventory of actual CO
emissions for year 1990 from all sources within the nonattainment area.
The inventory is to address actual CO emissions during the peak CO
season for the area, and all stationary (generally referring to larger
stationary source or ``point'' sources), area (generally referring to
smaller stationary and fugitive (non-smokestack) sources), and mobile
(on-road, nonroad, locomotive and aircraft) sources are to be included
in the inventory. Section 187(a)(5) requires States to submit periodic
(every three years) updates to the inventories required under section
187(a)(1).
We interpret the Act such that the emission inventory requirements
of section 172(a)(3), 187(a)(1), and 187(a)(5) are satisfied by the
inventory requirements of the maintenance plan. See 57 FR 13498, at
13564 (April 16, 1992). Thus, our proposed approval of the Las Vegas
Valley CO Maintenance Plan and related CO emission inventories
satisfies the requirements of sections 172(a)(3), 187(a)(1), and
187(a)(5) for the purposes of redesignation of Las Vegas Valley to
attainment for the CO NAAQS. See section V.D herein for details
concerning the CO emission inventories in the Maintenance Plan.
e. Permits for New and Modified Major Stationary Sources
Under section 172(c)(5), the CAA requires States to submit SIP
revisions that establish certain requirements for new or modified
stationary sources in nonattainment areas, including provisions to
ensure that major new sources or major modifications of existing
sources of nonattainment pollutants incorporate the highest level of
control, referred to as the Lowest Achievable Emission Rate (LAER), and
that increases in emissions from such stationary sources are offset so
as to provide for reasonable further progress towards attainment in the
nonattainment area. The process for reviewing permit applications and
issuing permits for new or modified stationary sources of air pollution
is referred to as ``New Source Review'' (NSR). With respect to
nonattainment pollutants in nonattainment areas, this process is
referred to as ``nonattainment NSR.''
In 2004 (69 FR 54006, September 7, 2004), we approved Clark
County's NSR rules as meeting the requirements of section 172(c)(5).
See our proposed rule at 69 FR 31056, at 31059 (June 2, 2004) for
details concerning how Clark County's NSR rules comply with CAA
requirements for CO nonattainment areas. We have also made a finding
under section 187(c)(1) that stationary sources do not contribute
significantly to ambient CO levels in the Las Vegas Valley CO
nonattainment area. See at 69 FR 56351, at 56353 (September 21, 2004).
For certain types of power plants in Clark County, NDEP rather than
Clark County has the authority to issue air pollution permits under
State law. In 2004, we approved a State rule (NAC section 445B.22083)
that prohibits new power plants or major modification to existing power
plants under State jurisdiction within the Las Vegas Valley
nonattainment area. See 69 FR 31056, 31059 (June 2, 2004) and 69 FR
54006, at 54017 (September 7, 2004). In 2008, we approved an amended
version of NAC section 445B.22083. See 73 FR 20536 (April 16, 2008).
Based on our previous approvals of Clark County's NSR rules and NAC
section 445B.22083, we find that the State has met the requirements of
CAA section 172(c)(5).
f. Contingency Provisions
Sections 172(c)(9) and 187(a)(3) of the Act require a State to
submit contingency measures that will be implemented if an area fails
to make reasonable further progress (RFP), if VMT estimates in the
attainment plan are exceeded, or if the area fails to attain by the
applicable attainment date. In 2005, based on our determination that
Las Vegas Valley had attained the CO NAAQS by the applicable attainment
date, we found that the CAA's requirement for the SIP to provide for CO
contingency provisions under CAA sections 172(c)(9) and 187(a)(3) no
longer applies to Las Vegas Valley. See 70 FR 31353 (June 1, 2005).
g. Conformity Requirements
Under section 176(c) of the Clean Air Act Amendments of 1990,
States were required to establish criteria and
[[Page 44741]]
procedures to ensure that Federally supported or funded projects
conform to the air quality planning goals in the applicable SIP.
Section 176(c) further provided that State conformity provisions must
be consistent with Federal conformity regulations that the CAA required
EPA to promulgate. EPA's conformity regulations are codified at 40 CFR
part 93, subparts A (referred to herein as ``transportation
conformity'') and B (referred to herein as ``general conformity'').
Transportation conformity applies to transportation plans, programs,
and projects developed, funded, and approved under title 23 U.S.C. or
the Federal Transit Act, and general conformity applies to all other
Federally-supported or funded projects. SIP revisions intended to
address the conformity requirements are referred to herein as
``conformity SIPs.''
In November 2008, EPA approved Clark County's transportation
conformity criteria and procedures as meeting the related SIP
requirements under part 51, subpart T (``Conformity to State or Federal
Implementation Plans of Transportation Plans, Programs, and Project
Developed, Funded or Approved Under Title 23 U.S.C. or the Federal
Transit Laws''). See 73 FR 66182 (November 7, 2008).
In August 2005, Congress passed the Safe, Accountable, Flexible,
Efficient Transportation Equity Act: A Legacy for Users (SAFETEA-LU),
which eliminated the requirement for States to adopt and submit
conformity SIPs addressing general conformity requirements. See 75 FR
17254 (April 5, 2010) for conforming changes to EPA's general
conformity regulations. Based on our approval of Clark County's
transportation conformity SIP and SAFETEA-LU's elimination of the
general conformity SIP requirement, we find that Clark County and the
State have met the requirements for conformity SIPs in Las Vegas Valley
under CAA section 176(c). In any event, EPA believes it is reasonable
to interpret the conformity requirements as not applicable for purposes
of evaluating a redesignation request under section 107(d)(3)(E). See
Wall v. EPA, 265 F.3d 426, 439 (6th Cir. 2001) upholding this
interpretation.
h. VMT Forecasts and Annual Updates
Under CAA section 187(a)(2)(A), States are required to submit a SIP
revision for serious CO nonattainment areas that contains a forecast of
VMT in the nonattainment area concerned for each year before the year
in which the plan projects the CO standard will be attained, and must
provide for annual updates of the VMT forecasts. In 2004, we approved
VMT forecasts and the responsible agencies' commitments to revise and
replace the VMT projections as needed and to monitor actual VMT levels
in the future, under section 187(a)(2)(A) of the Act (see RTC's
Resolution No. 149, approved into the SIP in 2004). Thus, we find that
the SIP requirement for VMT forecasts and annual updates for Las Vegas
Valley under CAA section 187(a)(2)(A) has been met.
i. Vehicle Inspection and Maintenance Program
Under section 187(a)(6), the CAA requires States with serious CO
nonattainment areas to submit a SIP revision that provides for a
vehicle I/M program that meets applicable Federal I/M requirements,
including the ``enhanced'' I/M performance standard. In 2004, we
approved the ``alternate low'' enhanced vehicle I/M program for Las
Vegas Valley and Boulder City as meeting the requirements of CAA
section 187(a)(6) and EPA's I/M Regulation (40 CFR part 52, subpart S
(``Inspection/Maintenance Program Requirements''). See at 69 FR 56351,
at 56353 (September 21, 2004). Since then, we have approved an update
to the statutory and regulatory elements of the vehicle I/M program.
See 73 FR 38124, at 38127 (footnote 31), and 74 FR 3975 (January 22,
2009). Thus, the vehicle I/M SIP requirement for Las Vegas Valley under
CAA section 187(a)(6) has been met.
j. TCMs To Offset VMT-Related Emissions Increases and To Provide for
RFP
Section 187(b)(2) of the Clean Air Act applies the requirements of
section 182(d)(1) to serious CO nonattainment areas with the purpose of
reducing CO emissions rather than emissions of volatile organic
compounds (VOC). Specifically, section 187(b)(2) requires States with a
serious CO nonattainment area to submit a SIP revision that identifies
and adopts specific enforceable transportation control strategies and
transportation control measures (collectively, ``TCMs'') to offset any
growth in CO emissions from growth in VMT or numbers of vehicle trips
in such area and to reduce motor vehicle CO emissions as necessary, in
combination with other emission reductions requirements, to provide for
RFP. As noted above, we approved the CO RFP demonstration for Las Vegas
Valley as part of our approval of the Las Vegas Valley 2000 CO Plan.
EPA has concluded that States are not required to submit such
measures if the SIP includes a demonstration that, despite growth in
projected VMT, CO emissions will decline each year through the
attainment year. See, e.g., EPA proposed approval of California's
redesignation request for the South Coast Air Basin at 72 FR 6986
(February 14, 2007); finalized at 72 FR 26718 (May 11, 2007). In the
General Preamble, we state that: ``If projected total motor vehicle
emissions during the ozone season in one year are not higher than
during the ozone season the year before, given the control measures in
the SIP, the VMT offset requirement is satisfied.'' General Preamble at
57 FR 13522. For CO areas, the General Preamble principle quoted above
applies to motor vehicle emissions of CO during the CO season.
The Las Vegas Valley 2000 CO Plan includes CO emissions inventories
for a base year (1996) and the attainment year (2000) that show a sharp
decline in CO motor vehicle emissions during the 1996 through 2000
period. See page 6-3 of the Las Vegas Valley 2000 CO Plan. We approved
the emissions inventories in 2004 (69 FR 56351, September 21, 2004).
Thus, no TCMs for Las Vegas Valley were required to prevent an increase
in emissions associated with a growth in VMT or vehicle trips, since
emissions decline each year through the attainment year despite
increases in VMT and vehicle trips. Nonetheless, the State did submit a
TCM/TDM program (RTC's CAT MATCH commuter incentive program) as part of
the Las Vegas Valley 2000 CO Plan. See 2000 CO Plan, appendix D,
sections 2 and 9. In 2004, we approved the TCM/TDM program under
section 187(b)(2) and our voluntary mobile source emissions reduction
program policy. See 69 FR 56351, at 56353 (September 21, 2004).
Based on our 2004 approval of the emissions inventories and RFP
demonstration from the Las Vegas Valley 2000 CO Plan that show that no
additional TCMs are required to offset VMT-related emissions increases
or to provide RFP, we find that the TCM-related requirements of CAA
section 187(b)(2) for Las Vegas Valley have been met.
k. Oxygenated Gasoline Program
Under sections 187(b)(3) and 211(m), the CAA requires States with
serious CO nonattainment areas to submit a SIP revision that provides
for an oxygenated gasoline program. Such a program must require
gasoline to be blended to contain not less than 2.7% oxygen by weight
during the period of the year during which CO levels are elevated
(i.e., the winter months). In 1999, we approved Clark County's
oxygenated gasoline rule, Section 53 (``Oxygenated
[[Page 44742]]
Gasoline Program'') as meeting the requirements under sections
187(b)(3) and 211(m). See 64 FR 29573 (June 2, 1999). Clark County AQR
Section 53 requires gasoline sold in Las Vegas Valley, Eldorado Valley,
Ivanpah Valley, and the Boulder City limits to be blended to contain
3.5% oxygen by weight each year from October 1st through March 31st. In
2004, we approved administrative changes to the rule. See 69 FR 56351,
at 56353 (September 21, 2004). Thus, the oxygenated gasoline
requirement under CAA sections 187(b)(3) and 211(m) has been met.
l. Clean Data Policy and CO Milestone Requirement
CAA section 187(d) (``CO Milestone'') applies to serious CO areas
and requires: (1) The State to submit a demonstration that the area has
achieved certain specific annual emission reductions; (2) EPA to
determine whether the demonstration is adequate; and (3) the State to
submit a plan revision, if EPA notifies the State that the CO milestone
demonstration is inadequate, that implements CAA section 182(g)(4)
economic incentive and transportation control programs sufficient to
achieve the specific annual emission reductions by the attainment date.
EPA has not approved a CO Milestone demonstration for Las Vegas Valley,
but, as explained below, the CO Milestone requirement is linked to the
RFP requirement in section 187(a)(7), and because RFP has no meaning
when the area has attained the standard, the CO Milestone requirement
similarly is no longer meaningful and no corresponding SIP revision is
required to be approved for purposes of redesignation.
In some designated nonattainment areas, monitored data demonstrates
that the NAAQS have already been achieved. Based on its interpretation
of the Act, EPA has determined that certain SIP submission requirements
of part D, subparts 1, 2, and 4 of the Act do not apply for purposes of
evaluating redesignation requests and therefore we do not require
certain submissions for an area that has attained the NAAQS. These
include RFP requirements, attainment demonstrations and contingency
measures, because these provisions have the purpose of helping achieve
attainment of the NAAQS.
The Clean Data Policy is the subject of two EPA memoranda setting
forth our interpretation of the provisions of the Act as they apply to
areas that have attained the relevant NAAQS. EPA also finalized the
statutory interpretation set forth in the policy in a final rule, 40
CFR 51.918, as part of its Final Rule to Implement the 8-hour Ozone
National Ambient Air Quality Standard--Phase 2 (Phase 2 Final Rule).
See discussion in the preamble to the rule at 70 FR 71645-71646
(November 29, 2005). We have also applied the same approach to the
interpretation of the provisions of subparts 1 and 4 applicable to
particulate matter with an aerodynamic diameter less than or equal to a
nominal 10 micrometers (PM-10). For detailed discussions of this
interpretation with respect to the CAA's PM-10 requirements for RFP,
attainment demonstrations, and contingency measures, see 71 FR 6352,
6354 (February 8, 2006); 71 FR 13021, 13024 (March 14, 2006); 71 FR
27440, 27443-27444 (May 11, 2006); 71 FR 40952, 40954 (July 19, 2006);
and 71 FR 63642 (October 30, 2006).
EPA believes that the legal bases set forth in detail in our Phase
2 Final rule, our May 10, 1995 memorandum from John S. Seitz, entitled
``Reasonable Further Progress, Attainment Demonstration, and Related
Requirements for Ozone Nonattainment Areas Meeting the Ozone National
Ambient Air Quality Standard'' (Seitz memo), and our December 14, 2004
memorandum from Stephen D. Page entitled ``Clean Data Policy for the
Fine Particle National Ambient Air Quality Standards'' (Page memo), are
equally pertinent to the interpretation of provisions of subparts 1 and
3 applicable to CO. EPA's interpretation of how the provisions of the
Act apply to areas with ``clean data'' is not logically limited to
ozone, particulate matter with an aerodynamic diameter less than or
equal to a nominal 2.5 micrometers (``fine particles'' or PM-2.5), and
PM-10, because the rationale is not dependent upon the type of
pollutant. Our interpretation that an area that is attaining the
standard is relieved of obligations to demonstrate RFP and to provide
an attainment demonstration and contingency measures pursuant to part D
of the CAA, pertains whether the standard is CO, 1-hour ozone, 8-hour
ozone, PM-2.5, or PM-10.
The reasons for relieving an area that has attained the relevant
standard of certain part D, subpart 1 and 2 (sections 171 and 172)
obligations, applies equally as well to part D, subpart 3, which
contains specific attainment demonstration and RFP provisions for CO
nonattainment areas. As we have explained in the 8-hour ozone Phase 2
Final Rule, our ozone and PM-2.5 clean data memoranda, and our approval
of PM-10 SIPs, EPA believes it is reasonable to interpret provisions
regarding RFP and attainment demonstrations, along with related
requirements, so as not to require SIP submissions if an area subject
to those requirements is already attaining the NAAQS (i.e., attainment
of the NAAQS is demonstrated with three consecutive years of complete,
quality-assured air quality monitoring data for ozone and PM, and two
consecutive years for CO). A number of U.S. Circuit Courts of Appeals
have upheld EPA rulemakings applying its interpretation of subparts 1
and 2 with respect to ozone. Latino Issues Forum v. EPA, Nos. 06-75831
and 08-71239 (9th Cir. March 2, 2009) (memorandum opinion); Sierra Club
v. EPA, 99 F.3d 1551 (10th Cir. 1996); Sierra Club v. EPA, 375 F.3d 537
(7th Cir. 2004); Our Children's Earth Foundation v. EPA, No. 04-73032
(9th Cir. June 28, 2005) (memorandum opinion). It has been EPA's
longstanding interpretation that the general provisions of part D,
subpart 1 of the Act (sections 171 and 172) do not require the
submission of SIP revisions concerning RFP for areas already attaining
the ozone NAAQS. In the General Preamble, we stated:
[R]equirements for RFP will not apply in evaluating a request for
redesignation to attainment, since, at a minimum, the air quality
data for the area must show that the area has already attained. A
showing that the State will make RFP towards attainment will,
therefore, have no meaning at that point. 57 FR at 13564.
See also page 6 of the Calcagni memo. EPA believes the same reasoning
applies to the CO RFP provisions of part D, subpart 3.
With respect to RFP, CAA section 171(1) states that, for purposes
of part D of title I, RFP:
means such annual incremental reductions in emissions of the
relevant air pollutant as are required by this part or may
reasonably be required by the Administrator for the purpose of
ensuring attainment of the applicable NAAQS by the applicable date.
The stated purpose of RFP is to ensure attainment by the applicable
attainment date, whether dealing with the general RFP requirement of
section 172(c)(2), the ozone-specific RFP requirements of sections
182(b) and (c), the PM-10 specific RFP requirements of section
189(c)(1), or the CO-specific RFP requirements of section 187(a)(7).
Section 187(a)(7) states that the SIP for moderate CO areas with a
design value greater than 12.7 ppm must:
provide a demonstration that the plan as revised will provide for
attainment of the carbon monoxide NAAQS by the applicable attainment
date and provisions for such specific annual emission reductions as
are necessary to attain the standard by that date.
[[Page 44743]]
This same requirement also applies to serious CO areas in accordance
with CAA section 187(b)(1).
It is clear that once the area has attained the standard, no
further specific annual emission reductions are necessary or
meaningful. With respect to CO areas, this interpretation is supported
by language in section 187(d)(3), which mandates that a State that
fails to achieve the milestone must submit a plan that assures that the
State achieves the ``specific annual reductions in carbon monoxide
emissions set forth in the plan by the attainment date.'' Section
187(d)(3) assumes that the requirement to submit and achieve the
milestone does not continue after attainment of the NAAQS.
If an area has in fact attained the standard, the stated purpose of
the RFP and specific annual emissions reductions requirements will have
already been fulfilled.\10\ The specific annual emission reductions
required are only those necessary to attain the standard by the
attainment date. EPA took this position with respect to the general RFP
requirement of section 172(c)(2) in the April 16, 1992 General Preamble
and also in the May 10, 1995 memorandum with respect to the
requirements of sections 182(b) and (c). We are proposing to extend
that interpretation to the specific provisions of part D, subpart 3.
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\10\ For PM-10 areas, we have concluded that it is a distinction
without a difference that section 189(c)(1) speaks of the PM-10
nonattainment area RFP requirement as one to be achieved until an
area is ``redesignated as attainment'', as opposed to section
172(c)(2), which is silent on the period to which the requirement
pertains, or the ozone and CO nonattainment area RFP requirements in
sections 182(b)(1) or 182(c)(2) for ozone and 187(a)(7) for CO,
which refer to the RFP requirements as applying until the
``attainment date'', since, section 189(c)(1) defines RFP by
reference to section 171(l) of the Act. Reference to section 171(l)
clarifies that, as with the general RFP requirements in section
172(c)(2) and the ozone-specific requirements of section 182(b)(1)
and 182(c)(2) and the CO-specific requirements of section 187(a)(7),
the PM-specific requirements may only be required for the purpose of
ensuring attainment of the applicable national ambient air quality
standard by the applicable date. 42 U.S.C. section 7501(1). As
discussed in the text of this rulemaking, EPA interprets the RFP
requirements, in light of the definition of RFP in section 171(l),
to be a requirement that no longer applies once the standard has
been attained.
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As noted above, CAA section 187(d), CO Milestone, applies to
serious CO areas and requires the State to submit a demonstration that
the area has achieved certain specific annual emission reductions. EPA
interprets this provision consistent with its interpretation of section
182(g) in subpart 2. See May 10, 1995 Seitz Memorandum at page 5.
There, EPA included in its identification of SIP submission
requirements linked with attainment and RFP requirements the ``Section
182(g) requirements concerning milestones that are based on the section
182(b)(1) and 182(c)(2)(B) and (C) submissions.'' In Subpart 3,
similarly, milestone requirements are based on the section 187(a)(7)
specific annual emission reduction requirements.
Thus, while Las Vegas Valley does not have an approved SIP with
respect to the CO Milestone demonstration, we believe that, for the
reasons set forth here and established in our prior ``clean data''
memoranda and rulemakings, a CO nonattainment area that has ``clean
data'' should be relieved of the part D, subpart 3 obligation to
provide the CAA section 187(d) CO milestone demonstration. Based on our
2005 determination that Las Vegas Valley attained the CO NAAQS by the
applicable attainment date, and the above detailed rationale, we
conclude that the requirement for a CO milestone demonstration under
section 187(d) no longer applies to Las Vegas Valley.
3. Conclusion With Respect to Section 110 and Part D Requirements
Based on our evaluation of the various SIP requirements and
submittals discussed above, we propose to find that the State has a
fully approved SIP for section 110 and part D requirements applicable
for purposes of redesignation of Las Vegas Valley for the CO NAAQS, and
that the criteria for redesignation in section 107(d)(3)(E)(ii) and (v)
are met.
C. The Area Must Show the Improvement in Air Quality Is Due to
Permanent and Enforceable Emissions Reductions
Section 107(d)(3)(E)(iii) precludes redesignation of a
nonattainment area to attainment unless EPA determines that the
improvement in air quality is due to permanent and enforceable
reductions in emissions resulting from implementation of the applicable
SIP and applicable Federal air pollution control regulations and other
permanent and enforceable regulations. If EPA makes such a
determination, then the criterion is satisfied.
The 2000 and 2005 Las Vegas Valley CO plans credit the following
control measures in demonstrating attainment of the CO NAAQS in Las
Vegas Valley: the Federal Motor Vehicle Control Program; the State's
vehicle I/M program; the State's Low RVP Rule (NAC section 590.065);
Clark County's wintertime gasoline requirements, including Clark County
AQR Section 53 (``Oxygenated Gasoline Program'') and the CBG Rule; and
to a lesser extent, the State's Alternative Fuels for Government Fleets
Program and RTC's voluntary TCM/TDM program. All of the State and local
control measures listed above have been approved into the SIP and are
thus Federally enforceable.
The Federal Motor Vehicle Control Program has contributed to
improved air quality through the gradual, continued turnover and
replacement of older vehicle models with newer models manufactured to
meet increasingly stringent Federal tailpipe emissions standards. The
emissions reductions from the Federal Motor Vehicle Control Program are
reflected in the emissions inventories and maintenance demonstration
discussed later in this document through the use of EPA's MOBILE
emission factor model for on-road motor vehicles. The State and local
control measures further reduce CO emissions from on-road motor
vehicles, the single largest source category in the CO emissions
inventory for Las Vegas Valley.
A rough sense of the effectiveness of the control measures to
reduce CO emissions can be gained by a comparison between area-wide CO
emissions in 1996 (a nonattainment year) with those in 2006 (an
attainment year). In 1996, area-wide CO emissions in Las Vegas Valley
were estimated to be approximately 662 tons per day (average winter
weekday), and in 2006, despite an increase in population and VMT of
approximately 90% and 70%, respectively, area-wide CO emissions dropped
approximately 10% (to 581 tons per day average winter weekday).\11\
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\11\ See tables 3-2 and 3-12 from the 2005 CO Plan for estimates
of population, VMT, and area-wide CO emissions.
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With respect to permanence and enforceability, none of the State or
local control measures relied upon for attainment have sunset clauses,
and all would continue to be implemented under the Las Vegas Valley CO
Maintenance Plan, with the exception of the State's Low RVP Rule, and
the County's CBG Rule.\12\ For the reasons set forth in section VI of
this document, we are proposing to approve the suspension or relaxation
of these two control measures because, among other reasons, the
maintenance demonstration in the Las Vegas Valley CO Maintenance
[[Page 44744]]
Plan shows that they are not necessary to maintain the CO standard, at
least through 2020. Moreover, as required under CAA section 175A(d),
Clark County has committed to reinstating the CBG Rule as a contingency
measure if needed to address any violations of the CO standard that
might occur after redesignation to attainment. The Nevada Department of
Agriculture has not yet made the commitment to seek reinstatement of
the Low RVP Rule, and thus our proposed approval of the relaxation of
the Low RVP Rule is contingent upon submittal of the necessary
commitment. The commitments to reinstatement of the wintertime gasoline
requirements by Clark County and the Nevada Department of Agriculture,
once approved, will become Federally enforceable under the CAA.
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\12\ The CO Maintenance Plan also lists the State's Alternative
Fuels for Government Fleets Program and RTC's TCM/TDM program as
contingency measures, meaning that the plan takes no credit for the
measures in its maintenance demonstration. However, the State has
not requested rescission, suspension, or relaxation of these two
control measures and thus they will remain Federally enforceable
control measures under the CAA until EPA approves such a request as
a revision to the Nevada SIP.
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With respect to the connection between the emissions reductions and
the improvement in air quality, the Las Vegas Valley CO Maintenance
Plan provides a demonstration that the air quality improvement in Las
Vegas Valley, that resulted in attainment of the CO NAAQS by 2000 and
continued attainment since then, is due to emission reductions from
implementation of the control measures discussed above and is not the
result of a local economic downturn or unusual or extreme weather
patterns. The demonstration shows that from 1990 to 2007, despite
increases in population, employment growth, increases in vehicle miles
traveled (VMT), and strong economic conditions, CO levels decreased.
The demonstration also examined wintertime meteorological data for the
years 1998 through 2007 to determine if favorable meteorology
influenced CO levels. The data showed that only a few periods had
favorable meteorology. See pages 5-1 through 5-10 of the Las Vegas
Valley CO Maintenance Plan.
Thus, we find that the improvement in CO air quality in Las Vegas
Valley is the result of permanent and enforceable emissions reductions
from a combination of the Federal Motor Vehicle Control Program and
EPA-approved State and local control measures. As such, we propose to
find that the criterion for redesignation set forth at CAA section
107(d)(3)(E)(iii) is satisfied.
D. The Area Must Have a Fully Approved Maintenance Plan Under CAA
Section 175A
Section 175A of the CAA sets forth the elements of a maintenance
plan for areas seeking redesignation from nonattainment to attainment.
We interpret this section of the Act to require, in general, the
following core elements: attainment inventory, maintenance
demonstration, monitoring network, verification of continued
attainment, and contingency plan. See Calcagni memo, pages 8 through
13.
Under CAA section 175A, a maintenance plan must demonstrate
continued attainment of the applicable NAAQS for at least ten years
after EPA approves a redesignation to attainment. Eight years after
redesignation, the State must submit a revised maintenance plan that
demonstrates continued attainment for the subsequent ten-year period
following the initial ten-year maintenance period. To address the
possibility of future NAAQS violations, the maintenance plan must
contain such contingency provisions, that EPA deems necessary, to
promptly correct any violation of the NAAQS that occurs after
redesignation of the area. Based on our review and evaluation of the
plan, as detailed below, we are proposing to approve the Las Vegas
Valley CO Maintenance Plan because we believe that it meets the
requirements of CAA section 175A.
1. Attainment Inventory
The plan must contain an attainment year emissions inventory to
identify a level of emissions in the area that is sufficient to attain
the CO NAAQS. This inventory is to be consistent with EPA's most recent
guidance on emissions inventories for nonattainment areas available at
the time and should represent emissions during the time period
associated with the monitoring data showing attainment. The inventory
should also be based on actual ``CO season data'' (i.e., wintertime)
emissions for an attainment year.
In this case, we have already approved an ``attainment year''
emissions inventory in that we approved the 2006 emissions inventory
contained in the 2005 CO plan. The emissions inventories in the Las
Vegas Valley CO Maintenance Plan represent updates to the previously
approved emissions inventories in the 2005 CO Plan. As with the
previous plan, the emission inventories in the Las Vegas Valley CO
Maintenance are comprehensive, including emissions from stationary
point sources, area sources, nonroad mobile sources, and on-road mobile
sources, and represent CO season data (weekday in December). As was the
case with the inventories in the 2000 and 2005 CO attainment plans for
Las Vegas Valley, the CO inventories in the Maintenance Plan are not
used directly to demonstrate maintenance of the CO standard, but they
reflect the same methods, factors, and assumptions used to develop the
CO emission rates used for the dispersion modeling analysis which
provides the basis for the maintenance demonstration.
As noted in our proposed approval of the 2005 CO Plan, the 2005 CO
Plan provided a comprehensive revision to the base year (1996)
emissions inventory and future year emissions projections reflecting
updated underlying data, such as population and VMT forecasts, and
updated methods, such as MOBILE6.2 and NONROAD2004. The 2005 CO Plan
presented an emissions inventory for years 2006, 2010, 2015, 2020, and
2030. The Las Vegas Valley CO Maintenance Plan presents emissions
inventories for 2008, 2010, and 2020 that were developed using similar
emissions calculations procedures, models, and assumptions as were used
for the 2005 CO Plan (and described in detail in our proposed approval
of the 2005 CO Plan at 71 FR 26910, at 26913-26915, May 9, 2006), but
that were revised to reflect use of:
Updated population and vehicle activity projections
developed by the Regional Transportation Commission (RTC) (from RTC's
FY2006-2030 Regional Transportation Plan, approved by RTC in October
2006);
Updated TransCAD travel demand model output from RTC;
Revised wintertime gasoline properties that assume
relaxation of the RVP limit from 9.0 psi to 13.5 psi, and suspension of
the County's CBG Rule (i.e., suspension of the local sulfur content and
aromatic hydrocarbon limits);\13\
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\13\ The revised wintertime gasoline specifications were used in
developing the emissions inventories in the Maintenance Plan to
calculate CO emissions from both on-road and nonroad gasoline-
powered vehicles.
---------------------------------------------------------------------------
An updated emissions factor model (NONROAD2005, Core Model
Version 2005a, February 2006) to estimate emissions for the nonroad
source category; and
Updated emissions information for Nellis Air Force Base.
In addition, the emissions projections in the Las Vegas Valley CO
Maintenance Plan take no credit for the RTC's TCM program or the
State's alternative fuels for government vehicles program. More
detailed descriptions of the 1996 base year inventory, the 2008
projected inventory, and the 2010 and 2020 projected inventory are
documented in the Las Vegas Valley CO Maintenance Plan on pages 7-2
through 7-8, and in the plan's Technical Support Document (attached to
the plan as appendix B).
We have summarized the emissions projections in table 2, below. As
shown
[[Page 44745]]
in table 2, on-road mobile sources would continue to dominate CO
emissions within the nonattainment area through the initial maintenance
period (i.e., 10 years beyond redesignation). The 2005 CO Plan
estimated on-road CO emissions at approximately 441 tons per day (see
table 3-12 of the 2005 plan) for year 2006, and the increase in CO
emissions from on-road mobile sources for 2008, 2010, and 2020 as shown
in table 2 (relative to 2006) reflects the change in wintertime
gasoline specifications, as described above. The change in wintertime
gasoline specifications has not yet occurred, and will not occur until
EPA approves the suspension/relaxation of the State and local gasoline
rules, as proposed herein, thus, the emissions projections shown in
table 2 below overestimate emissions that actually occurred in year
2008. Aggregate emissions of CO are expected to hold steady, or to
increase slightly, over the course of the initial maintenance period.
Table 2--Summary of CO Emissions in Tons per Day
[For a weekday in December]
----------------------------------------------------------------------------------------------------------------
2008 2010 2020
----------------------------------------------------------------------------------------------------------------
Point sources................................................... 15.8 15.8 15.8
Area sources.................................................... 13.9 14.7 18.6
Aviation........................................................ 39.7 42.2 53.5
Railway......................................................... 0.3 0.3 0.4
Non-road mobile sources......................................... 57.7 60.8 71.2
On-road mobile sources.......................................... 579.3 579.7 574.4
-----------------------------------------------
Total....................................................... 706.7 713.5 733.9
----------------------------------------------------------------------------------------------------------------
Source: See Las Vegas Valley CO Maintenance Plan, Table 7-3.
Based on our review and prior approval of the emissions inventories
(and related documentation) from the 2005 CO plan, and our review of
the changes to the earlier-approved inventories, we find that the 2006
emission inventory from the 2005 CO Plan suffices as an attainment
inventory for Las Vegas Valley, and that the emissions inventories in
the Maintenance Plan reflect the latest planning assumptions and
emissions models and provide a comprehensive and reasonably accurate
forecast of CO emissions in Las Vegas Valley for years 2010 and 2020.
As described in the next section in this document, dispersion modeling
results derived from the same emissions methods, factors and
assumptions used to develop the inventories provide the basis for the
demonstration of maintenance of the CO NAAQS through 2020.
2. Maintenance Demonstration
CAA section 175A(a) requires that the maintenance plan ``provide
for the maintenance of the national primary ambient air quality
standard for such air pollutant in the area concerned for at least 10
years after the redesignation.'' Generally, a State may demonstrate
maintenance of the CO NAAQS by either showing that future emissions
will not exceed the level of the attainment inventory or by modeling to
show that the future mix of sources and emissions rates will not cause
a violation of the NAAQS. For areas that are required under the Act to
submit modeled attainment demonstrations, the maintenance demonstration
should use the same type of modeling. Calcagni memorandum, page 9.
Because the attainment demonstration for Las Vegas Valley in the 2000
CO Plan, and revised in the 2005 CO Plan, relied upon modeling
techniques, the CO Maintenance Plan also relies on modeling techniques
to demonstrate maintenance of the standard through the initial
maintenance period.
The Las Vegas Valley CO Maintenance Plan builds upon, and updates,
previous modeling efforts conducted, most recently, in support of
attainment demonstration in the 2005 CO Plan. Like the previous
approved plan, the maintenance plan includes both area-wide modeling
analysis and micro-scale modeling analyses at heavily-traveled
intersections and local airports. As before, area-wide analysis, was
conducted using the Urban Airshed Model (UAM), and the micro-scale
analyses were conducted using CAL3QHC for local intersections, and the
Emissions Dispersion Modeling System (EDMS) for the local airports.
Generally, the micro-scale analyses combine the results of UAM modeling
with those using either CAL3QHC (for intersections) or EDMS (for
airports) to generate worst-case maximum CO concentrations in the
various analysis years. The maintenance demonstration is discussed on
pages 7-6 through 7-14 of the Maintenance Plan, and at more length in
appendix B to the plan.
The Maintenance Plan provides an area-wide UAM-based modeling
demonstration of maintenance from year 2008 through year 2020 using
December 8-9, 1996 episode conditions (which is the same episode used
in the 2000 and 2005 CO plans) to determine peak CO concentrations. The
UAM modeling for the Maintenance Plan uses updated emission inventories
(see table 2, above) that reflect continued implementation of those
control measures that are being retained for CO maintenance purposes,
including the State's vehicle I/M program and the county's wintertime
oxygenated gasoline program. The concentration estimates are shown in
table 3, below. The estimates in table 3 do not include any CO
emissions reductions from those measures in the maintenance plan that
are identified as contingency measures, such as the State's Low RVP
Rule and the County's CBG Rule.
In the area-wide modeling demonstration, spatial patterns of
predicted 8-hour CO are similar to those predicted by previous modeling
in the 2005 CO plan. While the CO concentrations estimated for the
Maintenance Plan are higher than those estimated in previous modeling
completed for the 2005 CO Plan (due to the suspended/relaxed gasoline
requirements assumed for the maintenance plan), they are below the 8-
hour CO standard of 9 ppm and decrease over time. Also, as in previous
modeling, the area-wide impact of McCarran Airport increases over time
with peak values increasing around the airport due to growth in airport
activities.
[[Page 44746]]
Table 3--Las Vegas Valley CO Maintenance Plan Area-Wide Modeling Results
[Peak 8-hour UAM concentrations]
------------------------------------------------------------------------
Concentration
Year (ppm)
------------------------------------------------------------------------
2008.................................................... 8.8
2010.................................................... 8.5
2020.................................................... 7.7
------------------------------------------------------------------------
Source: Table 7-4 of the Las Vegas Valley CO Maintenance Plan.
As noted above, in addition to the area-wide modeling effort, two
micro-scale models, CAL3QHC and EDMS, were used to predict maximum CO
concentrations at potential hot spot receptors at heavily traveled
intersections and at local area airports. CAL3QHC is used to predict
the micro-scale impacts of vehicles operating at congested
intersections. Vehicles operating under congested conditions spend more
time in idle mode that can contribute to high levels of CO near the
roadways. As in the 2005 CO plan, micro-scale modeling was completed
for three intersections (1) Eastern Avenue/Charleston Blvd., (2)
Eastern Avenue/Fremont Street, and (3) Fremont Street/Charleston Blvd.
These three intersections comprise the ``5 points'' area, which is near
the Sunrise Acres CO monitoring station. Traffic data from the 2005 CO
Plan were scaled based on updated TransCAD transportation modeling
outputs and combined with emission factors from MOBILE6.2 and worst-
case meteorological data to predict local hotspot concentrations. These
hourly results from the micro-scale model were then combined with
hourly concentrations from the background UAM grid cell to compute
maximum running 8-hour concentrations. The combined results from
CAL3QHC and UAM are shown in table 4, below.
Table 4--Las Vegas Valley CO Maintenance Plan Maximum Predicted Combined Modeling Results at Selected
Intersections
[Peak 8-hour CO concentrations]
----------------------------------------------------------------------------------------------------------------
Year
Intersection -----------------------------------------------
2008 2010 2020
----------------------------------------------------------------------------------------------------------------
Eastern Ave./Charleston Blvd.................................... 8.1 7.7 6.9
Eastern Ave./Fremont St......................................... 7.7 7.4 6.7
Fremont St./Charleston Blvd..................................... 7.0 6.7 6.0
----------------------------------------------------------------------------------------------------------------
Source: Table 3-2 in appendix B to the Las Vegas Valley CO Maintenance Plan.
To model the impact of airport sources, EDMS was used again as in
the 2005 CO Plan. This model was developed for evaluating the specific
emission sources typically located at airports. The hotspot results
from EDMS were combined with the results of the UAM analysis to predict
the concentrations at receptors around the airports. The Maintenance
Plan presents the results of the combined UAM and EDMS models for all
the future years in table 3-3 of appendix B. No values were modeled
above the 9.0 ppm CO standard at any publicly accessible receptor
location. The peak combined concentration at McCarran International
Airport for future years is 8.9 ppm for 2020.
Lastly, UAM was used to identify a safety margin \14\ to be
included in the on-road motor vehicle emissions budgets to facilitate
future transportation conformity determinations for CO during the
initial maintenance period. See section V.D.7 of this document for
EPA's review and proposed approval of the budgets in the Las Vegas
Valley CO Maintenance Plan.
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\14\ The term ``safety margin'' refers to the amount by which
the total projected emissions from all sources of a given pollutant
are less than the total emissions that would satisfy the applicable
requirement for reasonable further progress, attainment or
maintenance. See 40 CFR 93.101.
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To identify a safety margin consistent with maintenance of the CO
standard through the initial maintenance period, the maintenance plan
scaled up the on-road motor vehicle emissions initially estimated and
used for concentration modeling purposes (see table 2 above) over the
entire modeling domain to the point at which the peak 8-hour CO
concentration reached 8.9 ppm in 2008, 2010, and 2020. The on-road
motor vehicle emissions outside the central urban sub-domain were then
increased by an additional 60% in each year to reach a maximum peak 8-
hour CO concentration of just under 9.0 ppm in the peak UAM grid cell,
at peak UAM plus CAL3QHC receptor, or at the peak UAM plus EDMS
receptor. See pages 3-11 through 3-16 of appendix B to the Maintenance
Plan.
The target CO concentration was reached at the point where on-road
motor vehicle emissions were increased to 658 tpd (13% higher than
baseline 2008 on-road emissions), 686 tpd (18% higher), and 704 tpd
(23% higher), in 2008, 2010, and 2020, respectively. See table 3-5 of
appendix B to the Maintenance Plan. The corresponding peak 8-hour
modeled concentrations (assuming this higher level of on-road motor
vehicle emissions) ranged from 8.87 ppm in 2008 to 8.98 ppm in 2020.
The 2020 value reflects microscale analysis (combining UAM plus EDMS)
for a receptor at McCarron Airport. We find this procedure to be a
reasonable means to identify an acceptable safety margin for CO
emissions in Las Vegas Valley.
Based on our review of the documentation provided in the CO
maintenance plan as summarized above, we find that the revised modeling
results are consistent with the underlying emission estimates and
reflect reasonable methods and assumptions. Further, we find that the
revised modeling results demonstrate continued maintenance of the CO
NAAQS in Las Vegas Valley through 2020.
3. Monitoring Network
Continued ambient monitoring of an area is generally required over
the maintenance period. As discussed in section V.A of this document,
CO is currently monitored by Clark County DAQEM at five stations within
Las Vegas Valley. In the Las Vegas Valley CO Maintenance Plan (see page
7-15 of the plan), Clark County DAQEM indicates its intention to
continue operation of an air quality monitoring network consistent with
EPA's monitoring requirements in 40 CFR part 58 (``Ambient Air Quality
Surveillance'') to verify continued attainment of the CO NAAQS within
Las Vegas Valley. The Las Vegas Valley CO Maintenance Plan also states
that, in addition, Clark County DAQEM's CO monitoring network will be
reviewed annually pursuant to 40 CFR 58.10 to determine
[[Page 44747]]
whether the system continues to meet the monitoring objectives in 40
CFR part 58, appendix D. We find the County's commitment for continued
ambient CO monitoring as set forth in the Las Vegas Valley CO
Maintenance Plan to be acceptable.
4. Verification of Continued Attainment
NDEP, the State Board of Agriculture, and the Clark County Board of
County Commissioners have the legal authority to implement and enforce
the requirements of the Las Vegas Valley CO Maintenance Plan. This
includes the authority to adopt, implement and enforce any emission
control contingency measures determined to be necessary to correct CO
NAAQS violations. To verify continued attainment, Clark County DAQEM
commits in the Maintenance Plan to the continued operation of a CO
monitoring network that meets EPA monitoring requirements, and also to
conduct studies to determine whether additional or re-sited CO monitors
are necessary in response to measured changes in mobile source
parameters (e.g., VMT, fleet mix). See page 7-15 of the Las Vegas
Valley CO Maintenance Plan. This is acceptable.
5. Contingency Provisions
Section 175A(d) of the Act requires that maintenance plans include
contingency provisions, as EPA deems necessary, to promptly correct any
violations of the NAAQS that occur after redesignation of the area.
Such provisions must include a requirement that the State will
implement all measures with respect to the control of the air pollutant
concerned which were contained in the SIP for the area before
redesignation of the area as an attainment area.
Under section 175A(d), contingency measures identified in the
contingency plan do not have to be fully adopted at the time of
redesignation. However, the contingency plan is considered to be an
enforceable part of the SIP and should ensure that the contingency
measures are adopted expeditiously once they are triggered by a
specified event. The maintenance plan should clearly identify the
measures to be adopted, a schedule and procedure for adoption and
implementation, and a specific timeline for action by the State. As a
necessary part of the plan, the State should also identify specific
indicators or triggers, which will be used to determine when the
contingency measures need to be implemented.
The Las Vegas Valley CO Maintenance Plan identifies four specific
contingency measures: RTC's TDM/TCM program, the State's Alternative
Fuels for Government Fleets Program, Clark County's CBG Rule, and the
State's Low RVP Rule. All of these measures have been approved by EPA
into the SIP and are currently in effect. The first two measures would
remain in effect but are identified as ``contingency measures'' in the
Maintenance Plan because the maintenance demonstration takes no
emissions credit for these programs. EPA has concluded that contingency
measures need not be new measures that would be triggered by a
violation, but may consist of early implementation of measures that
provide surplus reductions beyond those needed for attainment or
maintenance. See ``Early Implementation of Contingency Measures for
Ozone and Carbon Monoxide (CO) Nonattainment Areas,'' memorandum from
G.T. Helms to EPA Air Branch Chiefs, August 13, 1993. Identification of
RTC's TDM/TCM program and the State's Alternative Fuels for Government
Fleets Program as contingency measures in the Las Vegas Valley CO
Maintenance Plan is acceptable because, based on the rationale
presented above, we believe that the Maintenance Plan adequately
demonstrates maintenance of the CO NAAQS without taking any credit for
these two measures.
With respect to the Clark County's CBG Rule and the State Board of
Agriculture's Low RVP Rule, we are proposing to approve the suspension
of the former, and the relaxation of the latter, in this document. As
noted above, contingency provisions must include a requirement that the
State will implement all measures with respect to the control of the
air pollutant concerned which were contained in the SIP for the area
before redesignation of the area as an attainment area. In this
instance, Clark County's CBG Rule and the State's Low RVP Rule are two
measures that were contained in the SIP prior to redesignation and thus
must be included as contingency measures in the maintenance plan. The
Maintenance Plan does in fact list both measures as contingency
measures (see page 5-8 of the Maintenance Plan), and we believe that,
by adopting the Las Vegas Valley CO Maintenance Plan, Clark County has
adequately committed to reinstate the suspended fuels program, if
necessary in light of a monitored violation of the CO NAAQS, and
thereby implement the related contingency measure. The State Department
of Agriculture has yet to specifically commit to seek reinstatement by
the Board of Agriculture of the Low RVP Rule if needed to remedy future
CO NAAQS violations in Las Vegas Valley. Based on our discussions with
Clark County, NDEP and the Department of Agriculture, however, we
expect that such a commitment from the Department of Agriculture will
be forthcoming in the near future, and we will not finalize our
proposed approval of the Maintenance Plan and redesignation request
unless and until we receive and approve the State's submittal of this
commitment as a revision to the Nevada SIP.
The contingency provisions of the Las Vegas Valley CO Maintenance
Plan (see pages 7-15 and 7-16 of the plan) are triggered upon the
occurrence of an exceedance of the 8-hour CO standard (i.e., a
monitored level of 9.5 ppm or greater) at any of the monitoring
stations in the area. Upon such an occurrence, Clark County DAQEM will
review and verify the monitoring data within three months, and
recommend contingency measures within six months. The types of
contingency measures envisioned under these circumstances would be
local, voluntary measures.
However, if a second exceedance occurs at the same monitoring site
within a consecutive two-year period, DAQEM will make a recommendation
to the Clark County Board of County Commissioners (within six months of
the second exceedance) from among those contingency measures
specifically listed in the Maintenance Plan, as described above,
including reinstatement of Clark County's CBG Rule and reinstatement of
the State's Low RVP Rule. The Maintenance Plan would not require
implementation of these contingency measures unless the area
experiences a violation of the 8-hour CO NAAQS (i.e. a second
exceedance at the same site during the same calendar year). The
Maintenance Plan states that the contingency measures will be
implemented six to 12 months after approval by the Clark County Board
of Commissioners, depending on the time needed to put the measures in
place. See page 7-16 of the Maintenance Plan.
Upon our review of the plan, as summarized above, we find that the
contingency provisions of the Maintenance Plan clearly identify
specific contingency measures, contain tracking and triggering
mechanisms to determine when contingency measures are needed, contain a
description of the process of recommending and implementing contingency
measures, and contain specific timelines for action. Thus, we conclude
that, with the exception of the absence of a commitment by the State
Department of
[[Page 44748]]
Agriculture to seek reinstatement by the Board of Agriculture of the
Low RVP Rule, the contingency provisions of the Las Vegas Valley CO
Maintenance Plan are adequate to ensure prompt correction of a
violation and therefore comply with section 175A(d) of the Act. We will
not take final action to approve the Maintenance Plan until we receive
the commitment by the State Department of Agriculture to seek
reinstatement of the Low RVP Rule if needed to remedy a future CO NAAQS
violation in Las Vegas Valley.\15\
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\15\ On July 12, 2010, the Nevada Department of Agriculture
initiated a 30-day comment period to solicit comment (or request a
public hearing) on the draft commitment regarding implementation of
the contingency measure in the Maintenance Plan related to
reinstatement of the Low RVP Rule. The Department's notice of intent
to solicit public comment, which includes the commitment language,
has been placed in the docket for this rulemaking. We have reviewed
the language of the Department's draft commitment and expect to
approve it if it is ultimately submitted to us without significant
modification.
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6. Subsequent Maintenance Plan Revisions
CAA section 175A(b) provides that States shall submit a SIP
revision 8 years after redesignation providing for maintaining the
NAAQS for an additional 10 years. The Las Vegas Valley CO Maintenance
Plan provides that Clark County DAQEM will prepare a revised
maintenance plan eight years after redesignation to attainment. See
page 7-17 of the Maintenance Plan.
7. Motor Vehicle Emissions Budgets
Transportation conformity is required by section 176(c) of the CAA.
Our transportation conformity rule (codified in 40 CFR part 93, subpart
A) requires that transportation plans, programs, and projects conform
to SIPs and establishes the criteria and procedures for determining
whether or not they do so. Conformity to the SIP means that
transportation activities will not produce new air quality violations,
worsen existing violations, or delay timely attainment of the national
ambient air quality standards.
Maintenance plan submittals must specify the maximum emissions of
transportation-related CO emissions allowed in the last year of the
maintenance period, i.e., the motor vehicle emissions budget (MVEB).
The submittal must also demonstrate that these emissions levels, when
considered with emissions from all other sources, are consistent with
maintenance of the NAAQS. In order for us to find these emissions
levels or ``budgets''adequate and approvable, the submittal must meet
the conformity adequacy provisions of 40 CFR 93.118(e)(4) and (5). For
more information on the transportation conformity requirement and
applicable policies on MVEBs, please visit our transportation
conformity Web site at: http://www.epa.gov/otaq/stateresources/transconf/index.htm.
The Las Vegas Valley CO Maintenance Plan includes the CO MVEBs
shown in table 5 below. The budgets are based on table 7-9 of the
Maintenance Plan and other documentation in section 7.5 of the plan.
See also the discussion of projected emissions in section V.D.2
(``Maintenance Demonstration'') of this document.
Table 5--Las Vegas Valley CO Maintenance Plan, Motor Vehicle Emissions
Budgets
[Winter weekday emissions in tons per day]
------------------------------------------------------------------------
Year MVEB
------------------------------------------------------------------------
2008.................................................... 658
2010.................................................... 686
2020.................................................... 704
------------------------------------------------------------------------
In setting MVEBs, States generally use the on-road motor vehicle
portion of the emission inventories in the associated plan. Clark
County, however, did not cap MVEBs at projected motor vehicle emissions
levels. Because overall projected levels of emissions from all sources
are expected to be significantly less than the levels necessary to
maintain the CO NAAQS, Clark County scaled up emissions in the
maintenance demonstration to set MVEBs at a higher level. As long as
emissions from all sources are lower than needed to provide for
continued maintenance of the standard, the State may allocate
additional emissions to future mobile source growth by assigning a
portion of the safety margin to the MVEBs (see 40 CFR 93.124).
The criteria by which we determine whether a SIP's MVEBs are
adequate and approvable for conformity purposes are outlined in 40 CFR
93.118(e)(4) and (5). The following paragraphs provide our review of
the budgets in the Las Vegas Valley CO Maintenance Plan against our
adequacy criteria and provide the basis for our proposed approval of
the MVEBs.
Under 40 CFR 93.118(e)(4)(i), we review a submitted plan to
determine whether the plan was endorsed by the Governor (or designee)
and was subject to a public hearing. The Las Vegas Valley CO
Maintenance Plan was submitted to EPA on September 18, 2008 by NDEP's
Administrator, the Governor of Nevada's designee for all SIP revision
submittals. This SIP submittal documents that the Clark County Board of
Commissioners held a public hearing on the plan on September 2, 2008,
and adopted the plan on that same date. Therefore, we conclude that the
plan and related budgets meet the criterion under 40 CFR
93.118(e)(4)(i).
Under 40 CFR 93.118(e)(4)(ii), we review a submitted plan to
determine whether the plan was developed through consultation with
Federal, State and local agencies, whether full implementation plan
documentation was provided to EPA, and whether EPA's stated concerns,
if any, were addressed. Consultation for development of this plan
largely consisted of public meetings (see appendix C to the Maintenance
Plan); discussions with Federal, State, and local transportation
planning agencies; and a public hearing, preceded by notices that were
published in a newspaper of general circulation. Documentation was
provided to EPA, and EPA's stated concerns were addressed. We conclude
that adequate consultation occurred prior to submittal of the
Maintenance Plan to EPA, and that EPA's concerns were adequately
addressed for the purposes of 40 CFR 93.118(e)(4)(ii).
Under 40 CFR 93.118(e)(4)(iii), we review a submitted plan to
determine whether the MVEBs are clearly identified and precisely
quantified. The Maintenance Plan clearly identifies and precisely
quantifies the CO MVEBs for the years 2008, 2010 and 2020 on page 7-15
of the plan (and table 5, above). We conclude therefore that the plan
and related budgets meet the adequacy criterion under 40 CFR
93.118(e)(4)(iii).
Under 40 CFR 93.118(e)(4)(iv), we review a submitted plan to
determine whether the MVEBs, when considered together with all other
emissions sources, are consistent with applicable requirements for
reasonable further progress, attainment, or maintenance (whichever is
relevant to a given SIP submission). The Maintenance Plan shows how the
MVEBs and related safety margins are consistent with maintenance of the
CO NAAQS through 2020 (see pages 7-6 through 7-15 of the Maintenance
Plan). In particular, Tables 7-6, 7-7, 7-8, and 7-9 of the Maintenance
Plan show the extent to which maximum future year emissions (including
the budget safety margins) fall below ambient concentration levels for
the 8-hour CO NAAQS. Consequently, we find that the plan and related
budgets meet this criterion for adequacy.
[[Page 44749]]
Under 40 CFR 93.118(e)(4)(v), we review a plan to determine whether
the MVEBs are consistent with and clearly related to the emissions
inventory and the control measures in the submitted control strategy
plan or maintenance plan. The MVEBs in the Maintenance Plan
appropriately reflect the measures relied upon for continued
maintenance of the CO standard in Las Vegas Valley, including the
wintertime oxygenated gasoline program and the State's vehicle I/M
program, as well as the decision by State and Clark County to suspend
or relax certain other wintertime gasoline requirements (i.e., suspend
the CBG Rule and relax the Low RVP Rule) and to take no CO credit for
certain other measures (i.e., the Alternative Fuels for Government
Fleets program and RTC's TDM/TCM program). Thus, we find that the MVEBs
are consistent with and clearly related to the emissions inventory and
the control measures in the submitted maintenance plan and thereby meet
the criterion for adequacy under 40 CFR 93.118(e)(4)(v).
Under 40 CFR 93.118(e)(4)(vi), we review a submitted plan to
determine whether revisions to previously submitted plans explain and
document any changes to previously submitted budgets and control
measures; impacts on point and area source emissions; any changes to
established safety margins; and reasons for the changes (including the
basis for any changes related to emissions factors or estimates of
vehicle miles traveled and changes in control measures). There are no
previously submitted CO maintenance plans for the Las Vegas Valley.
Changes in the MVEBs relative to the previously approved MVEBs from the
attainment plans (i.e., the Las Vegas Valley 2000 CO Plan and then
later from the Las Vegas Valley 2005 CO Plan) reflect updates to EPA's
MOBILE model, RTC's planning assumptions regarding employment and
population, and RTC's travel activity and fleet mix projections; the
decision to establish safety margins for motor vehicle emissions; and
the decision to take no CO emission reduction credit for certain
control measures (e.g., CBG Rule and Low RVP Rule). Thus, we find that
the Maintenance Plan meets the criterion for adequacy under 40 CFR
93.118(e)(4)(vi).
Under 40 CFR 93.118(e)(5), we review the State's compilation of
public comments and response to comments that are required to be
submitted with any SIP revision. Appendix C of the Maintenance Plan
submittal documents the notice for public comments on the draft
Maintenance Plan and documents the proceedings at the public hearing.
The only comments on the draft Maintenance Plan were submitted by EPA,
and appendix C (to the Maintenance Plan) documents how the draft
Maintenance Plan was amended in response to those comments. We find
Clark County DAQEM's responses to our comments on the draft plan to be
acceptable, and thus, we find that the Maintenance Plan meets the
criterion for adequacy under 40 CFR 93.118(e)(5).
For the reasons set forth above, we find that the MVEBs in the Las
Vegas Valley CO Maintenance Plan meet the requirements under 40 CFR
93.118(e)(4) and (5), and that the maintenance plan as a whole will
ensure maintenance of the CO NAAQS through the last year of the
maintenance plan. Thus, we propose to approve the motor vehicle
emissions budgets for transportation conformity purposes. If we
finalize our action as proposed, RTC (which is the area's Metropolitan
Planning Organization) and the U.S. Department of Transportation will
be required to use the CO MVEBs from the Maintenance Plan for future
transportation conformity determinations.\16\
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\16\ The current approved CO motor vehicle emissions budgets
from the 2005 CO (Attainment) Plan are: 690, 768, and 817 tons per
winter weekday for 2010, 2015, and 2015, respectively. See 71 FR
44587 (August 7, 2006). The Maintenance Plan does not explicitly
indicate that the budgets set forth therein are intended to replace
the budgets from the 2005 CO Plan. Thus, if EPA takes final action
to approve the Maintenance Plan budgets as proposed, then both sets
of budgets (i.e., those from the 2005 CO Plan, and those from the
Maintenance Plan) would apply because they relate to different CAA
requirements for the same years. As a practical matter, however, the
Maintenance Plan budgets, being lower than the 2005 CO Plan budgets,
would be the constraining budgets for determining conformity.
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EPA generally first reviews budgets submitted with an attainment,
RFP, or maintenance plan for adequacy, prior to taking action on the
plan itself. The availability of the Las Vegas CO Maintenance Plan with
the 2008, 2010, and 2020 budgets was announced for public comment on
EPA's adequacy Web page on September 30, 2008, at: http://www.epa.gov/otaq/transp/conform/adequacy.htm. The public comment period on the
adequacy of the budgets closed on October 30, 2008. EPA did not receive
any comments on the budgets, but did not complete the process and make
an adequacy determination on the budgets. Instead, we are now proposing
to approve the budgets.
8. Conclusion
For the reasons set forth above, we find that the Las Vegas Valley
CO Maintenance Plan satisfies the applicable CAA requirements,
including CAA section 175A, and thus, we propose to approve it as a
revision to the Nevada SIP under section 110(k)(3), contingent upon
receipt of a commitment from the State Department of Agriculture to
seek reinstatement by the State Board of Agriculture of the Low RVP
Rule if needed to remedy a future violation of the CO NAAQS in Las
Vegas Valley.
VI. Evaluation of Suspended or Relaxed Wintertime Gasoline
Specifications
As noted previously, NDEP's March 26, 2010 SIP revision includes an
amended State fuels rule that relaxes the existing wintertime gasoline
requirement for RVP (referred to herein as the ``Low RVP Rule''), and
includes the suspension by Clark County of their local Cleaner Burning
Gasoline (CBG) rule (referred to herein as the ``CBG Rule''). The CBG
Rule established sulfur and aromatics limits for gasoline sold in Clark
County during the period from November 1 to March 31.
On December 9, 2009, the State Board of Agriculture amended NAC
section 590.065 (i.e., the Low RVP Rule) to incorporate updated ASTM
standard specifications and to relax the vapor pressure limit for
wintertime gasoline sold in Clark from 9.0 psi to 13.5 psi.\17\ EPA
first approved the Low RVP Rule as a revision to the Nevada SIP in 2004
when EPA approved the rule as a CO control measure of the 2000 CO Plan.
See 69 FR 56351 (September 21, 2004). EPA's proposed approval of the
Low RVP Rule (68 FR 4141, January 28, 2003) describes how lower vapor
pressure in gasoline reduces CO emissions and the relative magnitude in
the corresponding reduction in vehicular CO emissions. Please see EPA's
January 28, 2003 proposed rule for additional information on this topic
at 68 FR 4141, 4150-4151.
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\17\ The State's wintertime vapor pressure limit (raised from
9.0 psi to 13.5 psi) would continue to apply to gasoline sold within
Clark County from October 1st through March 31st. Another revision
to the rule would extend the wintertime vapor pressure limit in
Clark County to ``any blend of gasoline and ethanol.''
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In our 2003 proposed approval of the Low RVP Rule, we considered
whether the RVP specification is preempted under the Act. Section
211(c)(4)(A) preempts certain State fuel regulations by prohibiting a
State from prescribing or attempting to enforce ``any control or
prohibition respecting any characteristic or component of a fuel or
fuel additive'' for the purposes of motor vehicle emission control, if
EPA has prescribed under section 211(c)(1), ``a control or prohibition
applicable to such characteristic or component of the fuel or fuel
additive,'' unless the State
[[Page 44750]]
control or prohibition is identical to the control or prohibition
prescribed by EPA. In our 2003 proposed rule, we concluded that,
because the Federal controls on RVP, promulgated under section 211(h)
and section 211(c)(1), apply only in the summer months, there would be
no Federal preemption of the State's Low RVP Rule. What was true in
2003 remains true today. There is still no Federal RVP control
applicable to gasoline in the wintertime, and thus, no Federal
preemption of the relaxed vapor pressure limit (13.5 psi) established
in amended NAC section 590.065.
Further, in 2004, EPA approved CBG into the Nevada SIP. See 69 FR
56351 (September 21, 2004). The CBG Rule is described in detail in
EPA's proposed approval of the rule and the related 2000 CO Plan on
January 28, 2003 (68 FR at 4151-4152). At the time, we also considered
whether the sulfur content and aromatics limits for CBG were preempted
under CAA section 211(c)(4)(C).\18\ As earlier explained, CAA section
211(c)(4)(A) preempts certain State fuel regulations by prohibiting a
State from prescribing or attempting to enforce ``any control or
prohibition respecting any characteristic or component of a fuel or
fuel additive'' for the purposes of motor vehicle emission control, if
EPA has prescribed under section 211(c)(1), ``a control or prohibition
applicable to such characteristic or component of the fuel or fuel
additive,'' unless the State control or prohibition is identical to the
control or prohibition prescribed by EPA. Further, under CAA section
211(c)(4)(C), a State may prescribe and enforce an otherwise preempted
fuel control if EPA approves the control into the State's SIP. In order
to approve a preempted control into a SIP, EPA must find that the State
control is necessary to achieve a NAAQS either because no other
measures that would bring about timely attainment exist or that such
measures exist but are either unreasonable or impracticable. CAA
section 211(c)(4)(C) is intended to ensure that a State resorts to a
fuel measure only if there are no available practicable and reasonable
non-fuel measures, and in our 2004 approval of the CBG Rule, we found
that Clark County's requirements for sulfur and aromatics limits were
``necessary'' to achieve the CO NAAQS.
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\18\ The CBG Rule establishes a maximum sulfur content limit of
80 ppm (by weight). With respect to sulfur content, producers and
importers must also meet a 40 ppm flat limit or an average limit of
30 ppm subject to the 80 ppm cap. The standards for aromatic
hydrocarbons include a 30% cap (by volume), with producers and
importers required to meet a 25% flat limit or an average limit of
22% (subject to the 30% cap). The applicable geographic area is
Clark County, and the applicable period for use of CBG is November
1st through March 31st.
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In addition, the Energy Policy Act of 2005 (EPAct) amended section
211(c)(4)(C) by including a number of provisions addressing State
``boutique''fuel programs.\19\ The EPAct required EPA, in consultation
with the Department of Energy, to determine the total number of fuels
approved into all SIPs under section 211(c)(4)(C) as of September 1,
2004, and to publish a list that identifies these fuels, the States and
Petroleum Administration for Defense Districts (PADD) in which they are
used. CAA section 211(c)(4)(C)(v)(II).
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\19\ While the phrase ``boutique''fuels programs can mean
different things, it generally refers to State fuels programs that
establish different requirements than the Federal fuels program
required in a given area, typically for the purpose of addressing
specific local air quality issues.
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On December 28, 2006, EPA published a notice containing the final
interpretation, which was by fuel type, of the EPAct provisions in the
Federal Register. See 71 FR 78192. We also determined and published a
list of a total of eight (8) fuel types approved into SIPs, under
section 211(c)(4)(C) as of September 1, 2004, the States and the PADD
in which they are used. Clark County CBG, which as earlier explained
has sulfur and aromatics content limits for gasoline in use during the
period from November 1 to March 31, is on the list.
The EPAct also placed the following three additional restrictions
on EPA's authority to waive preemption by approving a State fuel
program into SIPs under section 211(c)(4)(C):
First, EPA may not approve a State fuel program into the
SIP if it would cause an increase in the total number of fuel types
approved into SIPs as of September 1, 2004.
Second, in cases where EPA approval of a fuel would
increase the total number of fuel types on the list but not above the
number approved as of September 1, 2004, because the total number of
fuel types in SIPs is below the number of fuel types as of September 1,
2004, we are required to make a finding after consultation with DOE,
that the new fuel will not cause supply or distribution interruptions
or have a significant adverse impact on fuel producibility in the
affected or contiguous areas.
Third, with the exception of 7.0 psi RVP, EPA may not
approve a State fuel into a SIP unless that fuel type is already
approved in at least one SIP in the applicable PADD. CAA Section
211(c)(4)(C)(v)(I), (IV) and (V).
Therefore, EPAct also amended section 211(c)(4)(C) to make any new
EPA approvals of State fuels under section 211(c)(4)(C) significantly
more difficult by, for example, limiting the total number of approved
``boutique'' fuel types to the number of fuel types approved into SIPs
as of September 1, 2004. If there is no room on the list, for example,
then EPA cannot approve any more boutique fuels regardless of the needs
of a given area to address air pollution problems.
Lastly, CAA section 211(c)(4)(C)(v)(III) requires EPA to remove a
fuel from the boutique fuels list described above if a fuel either
ceases to be included in a SIP or if a fuel in a SIP is identical to a
Federal fuel formulation implemented by EPA. CBG will not cease to be
included in the SIP because, as earlier discussed, CBG is currently in
the SIP and will continue in the SIP as a specific contingency measure
in the Las Vegas Valley CO Maintenance Plan, and because we intend to
synchronize our final actions on the Maintenance Plan and the
(suspended) CBG Rule (and thereby avoid a gap in time when the CBG Rule
would not be either an active or contingency measure in the SIP). Thus,
in today's action, we are not proposing to remove CBG from the boutique
fuels list. In addition, since we are not approving any new fuel into
the SIP under section 211(c)(4)(C), no issues are raised concerning the
three restrictions on such an approval described above.
As a general matter, under CAA section 110(l), EPA may approve
relaxations or suspensions of control measures so long as doing so
would not interfere with attainment or maintenance of any of the NAAQS
or would otherwise conflict with applicable CAA requirements. In this
instance, the relaxation of the Low RVP Rule and the suspension of the
CBG Rule (and related sulfur and aromatics content limits) would not
conflict with any applicable CAA requirement. However, the changes to
the two fuels rules would affect the properties of the gasoline sold in
Clark County during the winter and would thereby change vehicular
emissions relative to those that would occur without these changes with
concomitant effects on ambient pollutant concentrations (and
potentially interfering with attainment or maintenance of the NAAQS).
To specify the changes in the properties of wintertime gasoline due
to the changes in the fuels rules, Clark County DAQEM commissioned a
study by ENVIRON and Sierra Research. The study was submitted as
appendix A to the Las Vegas Valley CO Maintenance Plan. As far as
changes to sulfur content are concerned, the study authors predict
[[Page 44751]]
essentially no increase in gasoline sulfur content due to the
applicability of Federal tier 2 gasoline sulfur limits [which are very
similar (30 ppm average, with an 80 ppm cap) to the corresponding
limits under the CBG rule]. We agree that any increase would be minimal
due to the similarities between the Federal sulfur limits and those in
the CBG Rule, and would expect the Federal gasoline sulfur content
limits to essentially backstop the emissions reductions associated with
the low sulfur content limit in the CBG Rule.
As far as aromatics are concerned, the study predicts an increase
in aromatic content from the current (2006) wintertime average of
approximately 20% (by volume) to approximately 23%, based on the
average aromatics content in gasoline nationwide. See page 12 of
appendix A to the Maintenance Plan. Moreover, wintertime gasoline RVP
could increase from the current (2006) average of 8.8 psi to as high as
13.5 psi in response to the relaxation of the Low RVP Rule. The
relative increases in aromatics and RVP would lead to higher emissions
of CO and VOC, and potentially of particulate matter as well. We review
these increases or potential increases, in the context of attainment
and maintenance of the CO, ozone, and particulate matter NAAQS in the
paragraphs that follow.
With respect to CO, we conclude that the changes in wintertime
gasoline specifications due to the rules changes would not interfere
with the NAAQS based on the modeling results documented in the Las
Vegas Valley CO Maintenance Plan and our proposed approval of the
Maintenance Plan herein. The modeling conducted for the Maintenance
Plan relies on emissions factors that take no credit for either the CBG
Rule or the Low RVP Rule and still demonstrates maintenance of the CO
NAAQS in Las Vegas Valley through 2020.
For the ozone NAAQS, we recognize that a portion of Clark County is
designated nonattainment for the 8-hour ozone NAAQS, and thus, absent
modeling results or other convincing evidence showing non-interference,
we would not normally approve a SIP revision that would result in an
increase in ozone precursors within the nonattainment area. However, in
the Las Vegas Valley CO Maintenance Plan, Clark County DAQEM contends
that there would be no interference with the ozone NAAQS in this
instance because the effect of the gasoline fuel changes is limited to
the winter months whereas ozone exceedances occur during the
summertime. See pages 6-2 and 6-3 of the Maintenance Plan. At the
outset, we generally find this line of reasoning for a non-interference
finding to be acceptable, but to gain a more detailed understanding of
the seasonal nature of ozone exceedances in Las Vegas Valley, we
reviewed ozone data by month to determine when exceedances of the 0.075
ppm, eight-hour average, ozone NAAQS occurred. The data indicates that,
over the past 6 years (2004-2009), all exceedances of the 0.075 ppm
standard occurred during and between the months of April and September.
Conversely, no ozone NAAQS exceedances were recorded from October
through March, which is the period of time affected by the suspension
of the CBG Rule and relaxation of the RVP specification. Thus, we find
that the changes in Clark County wintertime gasoline specifications
would not interfere with attainment or maintenance of the ozone NAAQS.
With respect to the 1987 (24-hour average) PM-10, Las Vegas Valley
is classified as a ``serious'' nonattainment area. See 40 CFR 81.329.
In 2004, EPA approved the ``serious'' area PM-10 plan for Las Vegas
Valley and approved the request to extend the applicable attainment
date to the end of 2006. See 69 FR 32273 (June 9, 2004). In our 2004
final rule approving the PM-10 plan, we approved a number of fugitive
dust rules, including Clark County Air Quality Regulations (AQR)
Sections 90 through 94, that limit emissions from such sources as open
areas and vacant lots; unpaved roads, unpaved alleys and unpaved
easement roads; unpaved parking lots; construction sites; and paved
roads and street sweeping equipment. In approving the Las Vegas Valley
``serious'' area PM-10 plan, we also indicated that we agreed with
Clark County DAQEM's conclusion that nonroad and on-road vehicle
exhaust are not significant source categories in Las Vegas Valley for
the purpose of implementing Best Available Control Measures (BACM). See
our proposed approval of the PM-10 plan at 68 FR 2954, at 2959 (January
22, 2003).
In the Las Vegas Valley CO Maintenance Plan, Clark County DAQEM
contends that the changes in wintertime gasoline specifications would
not interfere with the PM-10 NAAQS based on the determination in the
approved serious area PM-10 plan that vehicular exhaust is not a
significant source of PM-10 in Las Vegas Valley.\20\ See pages 6-3 and
6-4 of the Maintenance Plan. Clark County DAQEM also contends that
removing fuels controls has no impact on PM-10 emissions from vehicular
exhaust. Lastly, Clark County DAQEM points to the most recent PM-10
emissions inventory that shows vehicular exhaust to account for less
than one percent of the total PM-10 emissions in Las Vegas Valley in
year 2006.
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\20\ The significant source categories identified in the serious
area PM-10 plan for Las Vegas Valley are fugitive types of sources,
including disturbed vacant land/unpaved parking lots, construction
(including highway construction), and vehicular travel on paved and
unpaved roads. See 68 FR 2954, at 2959 (January 22, 2003).
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First of all, Clark County DAQEM is correct in pointing out that
vehicular exhaust was determined not to be a significant source of PM-
10 emissions in Las Vegas Valley for the purposes of implementing the
BACM requirement. We also believe that Clark County DAQEM's most recent
inventory presents reasonable estimates of existing sources of PM-10 in
Las Vegas Valley. As a general matter, we do not agree that removal of
fuels controls has no affect on vehicular exhaust emissions of PM-10,
but we recognize that the extent to which the higher aromatics content
(from 20% to 23%, by volume) and higher RVP (from 8.8 to 13.5 psi)
would affect PM-10 from vehicle exhaust, and whether that effect would
be positive or negative, is difficult to predict because EPA's MOBILE
emissions factor model, which was used in the development of the
Maintenance Plan, does not have the capability to quantify the
resulting emissions changes.
However, even assuming the effect would be an increase in PM-10
from vehicle exhaust, we can still find that the changes in wintertime
gasoline specifications due to the fuels changes would not interfere
with attainment of the PM-10 NAAQS, because, in addition to the minimal
impact of vehicular emissions on PM-10 concentrations in Las Vegas
Valley (based on PM-10 inventories), the area appears to have attained
the standard due to the implementation and enforcement of fugitive dust
controls. To determine whether Las Vegas Valley is attaining the PM-10
standard, we reviewed 2007-2009 PM-10 monitoring data from the various
monitoring stations for which Clark County DAQEM reports data into
EPA's Air Quality Database (AQS). The review of the data reveals two
exceedances (i.e., 24-hour-average concentrations equal to or greater
than 155 [mu]g/m\3\) over the 2007-2009 period, both of which were
recorded during year 2008 at the Craig Road PM-10 monitoring site in
North Las Vegas. The PM-10 monitor at the Craig Road site is a
continuous monitor,
[[Page 44752]]
and thus the expected number of days per year, averaged over the 2007-
2009 period, is less than 1.0,\21\ which means that the PM-10 NAAQS has
been met at the Craig Road monitor, and since the Craig Road monitor is
the only site recording any exceedances, it follows that the entire
valley has attained the standard.\22\
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\21\ The PM-10 NAAQS is 150 micrograms per cubic meter ([mu]g/
m\3\), 24-hour average concentration. The standard is attained when
the expected number of days per calendar year with a 24-hour average
concentration above 150 [mu]g/m\3\, as determined in accordance with
appendix K to 40 CFR part 50, is equal to or less than one. See 40
CFR 50.6.
\22\ An attainment finding is not the same as redesignation of
an area to attainment. The latter type of action can only be
approved by EPA if all of the criteria under CAA section
107(d)(3)(E) are met, including submittal of, and EPA approval of, a
maintenance plan.
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We do not believe that a hypothetical, incremental increase in PM-
10 emissions, from a source category (vehicular exhaust) estimated to
contribute less than 1% to the overall emissions inventory, would have
a discernible effect on ambient PM-10 concentrations. This lack of
discernible effect, coupled with an attainment finding, provides us
with a sufficient rationale for concluding that the changes in
wintertime gasoline properties, expected to occur with the relaxation
of the Low RVP Rule and the suspension of the CBG Rule, would not
interfere with attainment or maintenance of the PM-10 NAAQS in Las
Vegas Valley.
With respect to the 1997 (annual) and 2006 (24-hour) PM-2.5 NAAQS,
Las Vegas Valley and the various other hydrographic areas that comprise
Clark County, are designated as ``unclassifiable/attainment'' areas.
See 40 CFR 81.329. A review of AQS data from the various PM-2.5
monitoring sites in Clark County reveals that PM-2.5 concentrations are
well below the PM-2.5 NAAQS. Over the past three years, the highest
98th percentile value (for the 24-hour average), recorded at the
Sunrise Avenue site, is 23 [mu]g/m\3\, well below the corresponding 24-
hour NAAQS of 35 [mu]g/m\3\. The highest annual concentration, also
recorded as the Sunrise Avenue site, is 10.3 [mu]g/m\3\, well below the
corresponding annual NAAQS of 15.0 [mu]g/m\3\.
As discussed above for PM-10, the changes to wintertime gasoline
properties due to the relaxed Low RVP Rule and suspended County CBG
Rule could result in increases in PM-10 emissions from vehicular
exhaust. All of the PM-10 from vehicular exhaust can be assumed also to
be fine particulate matter (i.e., PM-2.5), and thus the changes to the
wintertime gasoline properties could also result in increased PM-2.5
emissions from vehicular exhaust. However, we have no reason to believe
that this hypothetical increase would be large enough to cause an
exceedance of the 24-hour or annual PM-2.5 NAAQS. Therefore, we
conclude that the changes in wintertime gasoline properties, expected
to occur with the relaxation of the Low RVP Rule and the suspension of
the CBG Rule, would not interfere with attainment or maintenance of the
PM-2.5 NAAQS in Clark County.
Based on our previous approvals of NAC section 590.065 (i.e., the
Low RVP Rule) and the CBG Rule, and the nature of the regulatory
changes submitted to us (e.g., relaxing a vapor pressure limit (not
subject to preemption), updating specifications and test methods in the
State rule, suspension of the county CBG rule) as well as the above
evaluation of the impact of the changes in wintertime gasoline
properties in Clark County on ambient CO, ozone, PM-10, and PM-2.5
concentrations, we find that the changes would not interfere with
attainment or maintenance of any of the NAAQS, nor would they interfere
with any applicable requirement of the Act, and thus are approvable
under CAA section 110(l). As such, we propose to approve the amendments
to NAC section 590.065, and suspension of the CBG Rule, as submitted by
NDEP on March 26, 2010, as revisions to the Nevada SIP.\23\
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\23\ In addition to gasoline vapor pressure requirements, NAC
section 590.065 also includes maximum content limits in gasoline for
lead, phosphorus, manganese, ethanol, and sulfur. See NAC section
590.065(7). Because none of these content limits relate to gasoline
vapor pressure requirements in Las Vegas Valley nor the CO emissions
reductions achieved therefrom, and because the subsection in NAC
section 590.065 containing these limits (i.e., subsection (7)) is
severable from the rest of the rule, we are not including NAC
section 590.065(7) in our proposed approval of amendments to NAC
section 590.065.
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VII. Proposed Action and Request for Comment
Under section 110(k)(3) of the Act, EPA is proposing to approve
NDEP's submittal dated September 18, 2008 of the Las Vegas Valley CO
Maintenance Plan as a revision to the Nevada SIP because we find that
it satisfies the requirements of section 175A of the CAA to include a
reasonably accurate and comprehensive attainment inventory, an adequate
maintenance demonstration, contingency provisions, and commitments to
continue operation of an acceptable ambient monitoring network to
verify continued attainment. Final approval of the Las Vegas Valley CO
Maintenance Plan would make Federally enforceable the commitments, such
as the commitment to continue operation of an adequate CO monitoring
network, and the contingency provisions, contained therein. In
addition, we are proposing to approve for transportation conformity
purposes the motor vehicle emissions budgets in the Las Vegas Valley CO
Maintenance Plan for years 2008, 2010, and 2020 because we find they
meet the criteria found in 40 CFR 93.118(e). The budgets for 2008, 2010
and 2020 are 658 tons per day, 686 tons per day, and 704 tons per day,
respectively (based on typical weekday during the winter).
Based in part on our proposed approval of the Las Vegas Valley CO
Maintenance Plan, we are also proposing to approve NDEP's September 18,
2008 request to redesignate Las Vegas Valley to attainment for the CO
NAAQS. In doing so, we find that the area has met all of the criteria
for redesignation under CAA section 107(d)(3)(E), i.e., the area has
attained the CO standard; EPA has fully approved the Las Vegas Valley
SIP for all requirements under section 110 and part D of the CAA that
are applicable for purposes of redesignation; the improvement in CO
conditions in Las Vegas Valley is due to permanent and enforceable
reductions; and as described above, the State has submitted a
maintenance plan for the area that meets the requirements of section
175A.
Contingency provisions in maintenance plans must include the
measures contained in the SIP prior to redesignation, and for one such
contingency measure included in the Las Vegas Valley CO Maintenance
Plans, the State's Low RVP Rule, the responsible State agency (State
Department of Agriculture) has not yet made the necessary commitment.
Thus, our proposed approval of the Maintenance Plan and redesignation
request is contingent upon submittal (and approval by EPA) of such a
commitment as a revision to the Nevada SIP.\24\
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\24\ On July 12, 2010, the Nevada Department of Agriculture
initiated a 30-day comment period to solicit comment (or request a
public hearing) on the draft commitment regarding implementation of
the contingency measure in the Maintenance Plan related to
reinstatement of the Low RVP Rule. The Department's notice of intent
to solicit public comment, which includes the commitment language,
has been placed in the docket for this rulemaking. We have reviewed
the language of the Department's draft commitment and expect to
approve it if it is ultimately submitted to us without significant
modification.
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We are also proposing to approve, under section 110(k)(3) of the
CAA, NDEP's March 26, 2010 submittal of the
[[Page 44753]]
suspension of Clark County's Air Quality Regulations (AQR) Section 54
(``Cleaner Burning Gasoline: Wintertime Program'') (``CBG
Regulation''), and the amendments to the NAC section 590.065, including
the relaxation in the State's wintertime gasoline RVP requirement for
Clark County from 9.0 to 13.5 psi, because we find that doing so would
not interfere with attainment or maintenance of any of the NAAQS or any
applicable requirement of the Clean Air Act for the purposes of CAA
section 110(l). We are not including subsection (7) of amended NAC
section 590.065 in our proposed approval because the limits in
subsection (7) of the amended rule are unrelated to the vapor pressure
requirement and associated CO emissions reductions, and are severable
from the rest of the rule.
We will accept comments from the public on this proposal for the
next 30 days.
VIII. Statutory and Executive Order Reviews
Under the CAA, redesignation of an area to attainment and the
accompanying approval of a maintenance plan under section 107(d)(3)(E)
are actions that affect the status of a geographical area and do not
impose any additional regulatory requirements on sources beyond those
imposed by State law. A redesignation to attainment does not in and of
itself create any new requirements, but rather results in the
applicability of requirements contained in the CAA for areas that have
been redesignated to attainment. Moreover, 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, these actions merely propose to approve a
State plan and redesignation request as meeting Federal requirements
and do not impose additional requirements beyond those imposed by State
law. For these reasons, these actions:
Are not ``significant regulatory actions'' subject to
review by the Office of Management and Budget under Executive Order
12866 (58 FR 51735, October 4, 1993);
Do not impose an information collection burden under the
provisions of the Paperwork Reduction Act (44 U.S.C. 3501 et seq.);
Are 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.);
Do 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);
Do not have Federalism implications as specified in
Executive Order 13132 (64 FR 43255, August 10, 1999);
Are not an economically significant regulatory action
based on health or safety risks subject to Executive Order 13045 (62 FR
19885, April 23, 1997);
Are not a significant regulatory action subject to
Executive Order 13211 (66 FR 28355, May 22, 2001);
Are 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
Do not provide EPA with the discretionary authority to
address, as appropriate, disproportionate human health or environmental
effects, using practicable and legally permissible methods, under
Executive Order 12898 (59 FR 7629, February 16, 1994).
In addition, this proposed rule does not have Tribal implications as
specified by Executive Order 13175 (65 FR 67249, November 9, 2000),
because the SIP is not approved to apply in Indian country located in
the State, and EPA notes that it will not impose substantial direct
costs on Tribal governments or preempt Tribal law. Nonetheless, EPA has
discussed the proposed action with the one Tribe, the Las Vegas Paiute
Tribe, located within Las Vegas Valley.
List of Subjects
40 CFR Part 52
Environmental protection, Air pollution control, Carbon monoxide,
Intergovernmental relations, Reporting and recordkeeping requirements.
40 CFR Part 81
Environmental protection, Air pollution control, Carbon monoxide,
National parks, Wilderness areas.
Dated: July 21, 2010.
Keith Takata,
Acting Regional Administrator, Region IX.
[FR Doc. 2010-18645 Filed 7-28-10; 8:45 am]
BILLING CODE 6560-50-P