[Federal Register Volume 77, Number 219 (Tuesday, November 13, 2012)]
[Proposed Rules]
[Pages 67600-67613]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2012-27562]


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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Parts 52 and 81

[EPA-R09-OAR-2012-0792;9750-9]


Approval and Promulgation of Implementation Plans and Designation 
of Areas for Air Quality Planning Purposes; State of Nevada; 
Redesignation of Clark County to Attainment for the 1997 8-Hour Ozone 
Standard

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.

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SUMMARY: EPA is proposing to approve, as a revision of the Nevada state 
implementation plan, the State's plan for maintaining the 1997 8-hour 
ozone standard in Clark County for ten years beyond redesignation, and 
the related motor vehicle emissions budgets, because they meet the 
applicable requirements for such plans and budgets. EPA is also 
proposing to approve a request from the Nevada Division of 
Environmental Protection to redesignate the Clark County ozone 
nonattainment area to attainment of the 1997 8-hour ozone National 
Ambient Air Quality Standard because the request meets the statutory 
requirements for redesignation under the Clean Air Act.

DATES: Comments must be received on or before December 13, 2012.

ADDRESSES: Submit your comments, identified by Docket ID Number EPA-
R09-OAR-2012-0792, by one of the following methods:
    1. http://www.regulations.gov: Follow the on-line instructions for 
submitting comments.
    2. Email: [email protected].
    3. Fax: 415-947-3579.
    4. Mail or Deliver: Ginger Vagenas (AIR-2), U.S. Environmental 
Protection Agency, Region IX, 75 Hawthorne Street, San Francisco, CA 
94105-3901. Deliveries are only accepted during the Regional Office's 
normal hours of operation.
    Instructions: All comments 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 Confidential Business Information (CBI) or 
other information whose disclosure is restricted by statute. 
Information that you consider CBI or otherwise protected should be 
clearly identified as such and should not be submitted through http://www.regulations.gov or email. http://www.regulations.gov is an 
anonymous access system, and EPA will not know your identity or contact 
information unless you provide it in the body of your comment. If you 
send email directly to EPA, your email address will be automatically 
captured and included as part of the public comment. 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.
    Docket: Generally, documents in the docket for this action are 
available electronically at www.regulations.gov and in hard copy at EPA 
Region IX, 75 Hawthorne Street, San Francisco, California. While all 
documents in the docket are listed at www.regulations.gov, some 
information may be publicly available only at the hard copy location 
(e.g., copyrighted material, large maps), and some may not be publicly 
available in either location (e.g., CBI). 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: Ginger Vagenas, Air Planning Office 
(AIR-2), U.S. Environmental Protection Agency, Region IX, (415) 972-
3964, [email protected].

SUPPLEMENTARY INFORMATION: Throughout this document, whenever ``we,'' 
``us,'' or ``our'' is used, we mean EPA. This supplementary information 
section is arranged 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 the Clark 
County 8-Hour Ozone Nonattainment Area
    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. Emissions Inventory
    c. Permits for New and Modified Major Stationary Sources
    d. Compliance With Section 110(a)(2)
    e. Conformity 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
VI. Proposed Action and Request for Public Comment
VII. Statutory and Executive Order Reviews

I. Summary of Today's Proposed Action

    EPA is proposing to take several related actions. First, under 
Clean Air Act (CAA or ``Act'') section 110(k)(3), EPA is proposing to 
approve a submittal from the Nevada Division of Environmental 
Protection (NDEP) dated April 11, 2011 of Clark County's Ozone 
Redesignation Request and Maintenance Plan (March 2011) (``Clark County 
Ozone Maintenance Plan'' or ``Ozone Maintenance Plan'') as a revision 
to the Nevada state implementation plan (SIP).
    In connection with the Clark County Ozone Maintenance Plan, EPA 
finds that the maintenance demonstration showing how the area will 
continue to attain the 1997 8-hour ozone national ambient air quality 
standard (NAAQS) for 10 years beyond redesignation (i.e., through 2022) 
and the contingency provisions describing the actions that Clark County 
will take in the event of a future monitored violation meet all 
applicable requirements for maintenance plans and related contingency 
provisions in CAA section 175A. EPA is also proposing to approve the 
motor vehicle emissions budgets (MVEBs) in the Clark County Ozone 
Maintenance Plan because we find they meet the applicable 
transportation conformity requirements under 40 CFR 93.118(e).
    Second, under CAA section 107(d)(3)(D), EPA is proposing to approve 
NDEP's request that accompanied the submittal of the maintenance plan 
to redesignate the Clark County 8-hour ozone nonattainment area to 
attainment for the 1997 8-hour ozone NAAQS. We are doing so based on 
our conclusion that the area has met the five criteria for

[[Page 67601]]

redesignation under CAA section 107(d)(3)(E). Our conclusion in this 
regard is in turn based on our proposed determination that the area has 
attained the 1997 8-hour ozone NAAQS, that relevant portions of the 
Nevada SIP are fully approved, that the improvement in air quality is 
due to permanent and enforceable reductions in emissions, that Nevada 
has met all requirements applicable to the Clark County 8-hour ozone 
nonattainment area with respect to section 110 and part D of the CAA, 
and based on our proposed approval as part of this action of the Clark 
County Ozone Maintenance Plan.

II. Background

    Ground-level ozone is generally not emitted directly by sources. 
Rather, directly-emitted oxides of nitrogen (NOX) and 
volatile organic compounds (VOC) react in the presence of sunlight to 
form ground-level ozone, as a secondary pollutant, along with other 
secondary compounds. NOX and VOC are ``ozone precursors.'' 
Reduction of peak ground-level ozone concentrations is typically 
achieved through controlling VOC and NOX emissions.
    In 1971, under section 109 of the Act, as amended in 1970, EPA 
promulgated the original NAAQS for several pervasive air pollutants, 
including photochemical oxidants. 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).
    In 1978, EPA designated the Las Vegas Valley (hydrographic area No. 
212) as a nonattainment area for the photochemical oxidant NAAQS. See 
43 FR 8962 (March 3, 1978). In 1979, EPA revised the NAAQS from an 
hourly average of 0.08 parts per million (ppm) oxidant to an hourly 
average of 0.12 ppm ozone. See 44 FR 8202 (February 8, 1979). The 
nonattainment designation for Las Vegas Valley for photochemical 
oxidant carried over to the 1-hour ozone NAAQS.
    During the 1980s, Clark County adopted a number of rules and 
prepared a number of nonattainment plans to address planning 
requirements under the CAA, as amended in 1977. NDEP submitted these 
rules and plans to EPA at various times, and EPA approved a number of 
them into the Nevada SIP. Among the rules approved by EPA as revisions 
to the Nevada SIP as part of the ozone control strategy in Las Vegas 
Valley are Clark County air pollution rules section 33, which relates 
to chlorine in chemical processes); sections 50, 51, and 52, which 
relate to storage and distribution of petroleum products; and section 
60, which relates to evaporation and leakage. In 1986, in light of the 
approved control strategy and monitored levels below the NAAQS, EPA 
redesignated Las Vegas Valley to attainment for the 1-hour ozone NAAQS. 
See 51 FR 41788 (November 19, 1986).
    In 1997, EPA revised the NAAQS for ozone, setting it at 0.08 ppm 
averaged over an 8-hour time frame (``1997 8-hour ozone standard''). 
EPA set the 1997 8-hour ozone standard based on scientific evidence 
demonstrating that ozone causes adverse health effects at lower ozone 
concentrations and over longer periods of time, than was understood 
when the pre-existing 1-hour ozone standard was set. EPA determined 
that the 1997 8-hour standard would be more protective of human health, 
especially for children and adults who are active outdoors, and 
individuals with a pre-existing respiratory disease, such as asthma.\1\
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    \1\ On March 27, 2008 (73 FR 16436), EPA promulgated a revised 
8-hour ozone standard of 0.075 ppm (the 2008 8-hour ozone standard), 
and on May 21, 2012, EPA designated the entire state of Nevada 
unclassifiable/attainment for the 2008 8-hour ozone standard (77 FR 
30088). This rulemaking relates only to the 1997 8-hour ozone 
standard and does not relate to the 2008 8-hour ozone standard.
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    In 2004, EPA designated areas of the country with respect to the 
1997 8-hour ozone NAAQS. See 69 FR 23858 (April 30, 2004). Under EPA's 
``Phase 1'' implementation rule for the 1997 8-hour ozone standard (69 
FR 23951, April 30, 2004), an area was classified under subpart 2 based 
on its 8-hour ozone design value (i.e., the 3-year average annual 
fourth-highest daily maximum 8-hour average ozone concentration at the 
worst-case monitoring site in the area or in its immediate downwind 
environs), if it had a 1-hour ozone design value \2\ at the time of 
designation at or above 0.121 ppm. All other areas were covered under 
subpart 1 based on their 8-hour ozone design values \3\ (69 FR 23951). 
Clark County was designated as a ``subpart 1'' ozone nonattainment area 
by EPA on April 30, 2004 based on air quality monitoring data from 
2001-2003. The designation became effective on June 15, 2004. On 
September 17, 2004, EPA reduced the geographic extent of the ozone 
nonattainment area to encompass a portion of, but not all of, Clark 
County.\4\ See 69 FR 55956 (September 17, 2004), 70 FR 71612 (November 
29, 2005), and 40 CFR 81.329.
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    \2\ The design value for the 1-hour ozone standard is the 
fourth-highest daily maximum 1-hour ozone concentration over a 
three-year period at the worst-case monitoring site in the area.
    \3\ The design value for the 8-hour standard is the three-year 
average of the annual fourth-highest daily maximum 8-hour ozone 
concentration at the worst-case monitoring site in the area.
    \4\ The boundaries of the Clark County ozone nonattainment area 
are defined in 40 CFR 81.329. Specifically, the area is defined as: 
``That portion of Clark County that lies in hydrographic areas 164A, 
164B, 165, 166, 167, 212, 213, 214, 216, 217, and 218 but excluding 
the Moapa River Indian Reservation and the Fort Mojave Indian 
Reservation.'' The area includes a significant portion of the 
unincorporated portions of central and southern Clark County, as 
well as the cities of Las Vegas, Henderson, North Las Vegas, and 
Boulder City.
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    On December 22, 2006, the U.S. Court of Appeals for the District of 
Columbia Circuit (DC Circuit) vacated EPA's Phase 1 implementation rule 
for the 1997 8-hour ozone standard (69 FR 23951, April 30, 2004). South 
Coast Air Quality Management Dist. v. EPA, 472 F.3d 882 (DC Cir. 2006). 
On June 8, 2007, in response to several petitions for rehearing, the DC 
Circuit Court (Court) clarified that the Phase 1 rule was vacated only 
for those parts of the rule that had been successfully challenged. The 
June 8, 2007, decision left intact the Court's rejection of EPA's 
reasons for implementing the 8-hour ozone standard in certain 
nonattainment areas under subpart 1 in lieu of subpart 2 of the CAA.
    On May 14, 2012, in response to the Court's vacating of the 
provision of EPA's Phase 1 implementation rule for the 1997 8-hour 
ozone standard that placed certain nonattainment areas, including Clark 
County solely under subpart 1, EPA classified Clark County as a 
marginal ozone nonattainment area under subpart 2 of the CAA (77 FR 
28424).
    On July 28, 2008, NDEP submitted the 8-hour Ozone Early Progress 
Plan for Clark County, Nevada (June 2008) (``Clark County Ozone EPP'') 
to EPA as a revision to the Nevada SIP. The purpose of the Clark County 
Ozone EPP was to establish motor vehicle emissions budgets (MVEBs) 
consistent with progress towards attainment of the 1997 8-hour ozone 
standard in advance of completion and submittal of an attainment 
demonstration. The Clark County EPP established MVEBs of 64.2 and 76.1 
tons per day (ozone season) for VOC and NOX, respectively, 
for 2008. On May 5, 2009, EPA found the MVEBs in the Clark County EPP 
adequate for the purposes of transportation conformity. See 74 FR 22738 
(May 14, 2009). Since the effective date of EPA's adequacy finding 
(i.e., May 29, 2009), the applicable metropolitan planning organization 
(MPO), i.e., the Regional Transportation Commission of Southern Nevada 
(RTC), and the U.S. Department

[[Page 67602]]

of Transportation have been required to use these budgets in 
transportation conformity analyses for regional transportation plans, 
programs and projects.
    On March 29, 2011, EPA determined that the Clark County 8-hour 
ozone nonattainment area had attained the 1997 8-hour ozone NAAQS, 
based on complete, quality-assured, and certified ambient air 
monitoring data that showed the area monitored attainment of the 1997 
8-hour ozone NAAQS for the 2007-2009 monitoring period (76 FR 17343). 
As a result, the obligation for the State of Nevada to submit an 
attainment demonstration and associated reasonably available control 
measures (RACM), a reasonable further progress (RFP) plan, contingency 
measures and other planning requirements related to attainment of the 
1997 8-hour ozone NAAQS was suspended until such time as: the area is 
redesignated to attainment, at which time the requirements no longer 
apply; or EPA determines that the area has violated the 1997 8-hour 
ozone NAAQS. See 40 CFR 51.918. In this action, we are updating the 
determination of attainment to account for more recent ozone monitoring 
data consistent with the applicable criterion for redesignation under 
CAA section 107(d)(3)(E)(i).
    Lastly, on April 11, 2011, NDEP submitted the Clark County Ozone 
Maintenance Plan and requested that EPA redesignate the Clark County 8-
hour ozone nonattainment area to attainment for the 1997 8-hour ozone 
standard. We are proposing action today on the NDEP's April 11, 2011 
redesignation request and submittal of the Clark County Ozone 
Maintenance Plan.

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 NDEP's April 11, 2011 submittal of 
the Clark County Ozone Maintenance Plan as a revision to the Nevada 
SIP.
    Appendix C of the Clark County Ozone Maintenance Plan documents the 
public review process followed by Clark County in adopting the plan 
prior to transmittal to NDEP for subsequent submittal to EPA as a 
revision to the Nevada SIP. The documentation in appendix C provides 
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 ozone maintenance plan was published on 
December 12, 2010 in a newspaper of general circulation within the Las 
Vegas area and on the County's Web page. No comments were submitted.
    On February 1, 2011, the Clark County Board of Commissioners set a 
public hearing for March 15, 2011 to consider and approve the Clark 
County Ozone Maintenance Plan. The announcement of the public hearing 
was subsequently published on the County's Web page. On March 15, 2011, 
the Clark County Board of Commissioners adopted the Clark County Ozone 
Maintenance Plan at the close of the public hearing. Following 
adoption, Clark County Department of Air Quality (DAQ) 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 on April 11, 2011.
    Based on the documentation contained in appendix C of the plan, we 
find that the submittal of the Clark County Ozone Maintenance Plan as a 
SIP revision satisfies the procedural requirements of section 110(l) of 
the Act for revising SIPs.

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, and part D 
establishes the SIP requirements for nonattainment areas. Part D is 
divided into six subparts. The generally-applicable nonattainment SIP 
requirements are found in part D, subpart 1, and the ozone-specific 
nonattainment SIP requirements are found in part D, subpart 2.
    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 Clark County 
8-hour ozone nonattainment area to attainment for the 1997 8-hour ozone 
NAAQS based on our conclusion that all of the criteria under CAA 
section 107(d)(3)(E) have been satisfied.

V. Evaluation of the State's Redesignation Request for the Clark County 
8-Hour Ozone Nonattainment Area

A. Determination That the Area Has Attained the Applicable NAAQS

    CAA section 107(d)(3)(E)(i) requires that we determine that the 
area has attained the NAAQS. EPA generally makes the determination of 
whether an area's air quality meets the ozone NAAQS based upon the most 
recent three years of complete, quality-assured data gathered at 
established State and Local Air Monitoring Stations (SLAMS) in the 
nonattainment area and entered into the EPA Air Quality System (AQS) 
database. Data from air monitors operated by state/local agencies in 
compliance with EPA monitoring requirements must be submitted to AQS. 
Heads of monitoring agencies annually certify that these data are 
accurate to the best of their knowledge. Accordingly, EPA relies 
primarily on data in AQS when determining the attainment status of 
areas. See 40 CFR 50.10; 40 CFR part 50, appendix I; 40 CFR part 53; 40 
CFR part 58, appendices A, C, D and E. All data are reviewed to 
determine the area's air quality status in accordance with 40 CFR part 
50, appendix I.
    Under EPA regulations at 40 CFR part 50, the 1997 8-hour ozone 
standard is attained at a site when the 3-year average of the annual 
fourth-highest

[[Page 67603]]

daily maximum 8-hour average ozone concentrations at an ozone monitor 
is less than or equal to 0.08 ppm. See 40 CFR 50.10. This 3-year 
average is referred to as the design value. When the design value is 
less than or equal to 0.084 ppm (based on the rounding convention in 40 
CFR part 50, appendix I) at each monitoring site within the area, then 
the area is meeting the NAAQS. The data completeness requirement is met 
when the three-year average percent of days with valid ambient 
monitoring data is at least 90%, and no single year has less than 75% 
data completeness as determined in appendix I of 40 CFR part 50.
    The Clark County Department of Air Quality (DAQ), (previously known 
as Clark County Department of Air Quality and Environmental Management, 
or DAQEM) is responsible for monitoring ambient air quality within 
Clark County. DAQ submits monitoring network plan reports to EPA on an 
annual basis. These reports discuss the status of the air monitoring 
network, as required under 40 CFR part 58. Beginning in 2007, EPA has 
reviewed these annual plans for compliance with the applicable 
reporting requirements in 40 CFR 58.10. With respect to ozone, we have 
found DAQ's annual network plans to meet the applicable requirements 
under 40 CFR part 58. See EPA letters to DAQ concerning DAQ's annual 
network plan reports for 2010 and 2011, included in the docket for this 
rulemaking. Furthermore, we concluded in our Technical System Audit 
Report (February 2010) that Clark County DAQ's ambient air monitoring 
network currently meets or exceeds the requirements for the minimum 
number of monitoring sites designated as SLAMS for all of the criteria 
pollutants. Also, DAQ annually certifies that the data it submits to 
AQS are complete and quality-assured. See, e.g., the letter dated 
February 28, 2012, from Lewis Wallenmeyer, Director, DAQ, to Jared 
Blumenfeld, EPA Region IX Regional Administrator.
    Clark County DAQ operated 13 ozone SLAMS monitoring sites during 
the 2009-2011 period \5\ within the Clark County ozone nonattainment 
area: Apex (Apex Valley), Boulder City (City of Boulder City), Craig 
Road (City of North Las Vegas), J.D. Smith School (City of North Las 
Vegas), Jean (City of Jean, south of Las Vegas), Jerome Mack (near 
North Las Vegas Airport), Joe Neal (northwest Las Vegas), Lone Mountain 
(northwest Las Vegas), Orr School (central-southeast Las Vegas), Paul 
Meyer Park (southwest Las Vegas), Palo Verde School (west Las Vegas), 
Walter Johnson (west Las Vegas), and Winterwood (southeast Las Vegas). 
All 13 sites have monitored ozone concentrations on a continuous basis 
using ultraviolet absorption monitors.\6\ The spatial scale and 
monitoring objective of most of DAQ's ozone monitoring sites are 
``neighborhood'' and ``population exposure,'' respectively. The 
exceptions are the Apex and Jean sites, whose spatial scale and 
monitoring objective is ``regional'' and ``regional transport,'' 
respectively, and the Joe Neal site, whose spatial scale is 
``neighborhood'' and monitoring objective is ``highest concentration.'' 
See ``Clark County Department of Air Quality and Environmental 
Management--Annual Network Plan Report (June 2011).''
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    \5\ As allowed by 40 CFR 58.14, Clark County DAQ has 
periodically modified its monitoring network and therefore not all 
monitors operated over the entire 2009-2011 period. In 2010, the 
Craig Road, Lone Mountain, and Orr monitors were discontinued. EPA 
has approved the discontinuation of these sites (see letter dated 
October 23, 2012 from Matthew Lakin, Manager, Air Quality Analysis 
Office, EPA Region IX to Mike Sword, Engineering Manager, Clark 
County DAQ). Clark County's monitoring network has exceeded the 
number of required monitors throughout the referenced time period.
    \6\ DAQ operates Federal equivalent method (FEM) monitors for 
ozone. Specifically, API 400 Series ultraviolet absorption monitors. 
See the Clark County DAQ ``Annual Network Plan Report'', page 12, 
June 2011. These monitoring devices have an EPA designation number 
EQOA-0992-087. See EPA ``List of Designated Reference and Equivalent 
Methods'', page 28, June 6, 2012, available at: http://www.epa.gov/ttn/amtic/criteria.html.
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    Consistent with the requirements contained in 40 CFR part 50, EPA 
has reviewed the ozone ambient air monitoring data for the monitoring 
period from 2009 through 2011 collected at the monitoring sites 
discussed above, as recorded in AQS and summarized in table 1, and 
found that the data meet our completeness criteria, except at the 
discontinued or newly-operating monitoring sites.\7\
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    \7\ Also, the data from the Boulder City ozone monitor did not 
meet EPA's completeness criteria during year 2010 because of a 
temporary shutdown (from November 2009 through March 2010) (i.e., 
the low ozone season) due to station repairs. This temporary 
shutdown was approved by EPA. See page 71 of the Clark County DAQ 
Annual Network Plan Report, June 2010. In addition, the data from 
the Apex ozone monitor likewise did not meet EPA completeness 
criteria during 2010 and 2011 but EPA has approved a shortened ozone 
monitoring season at the Apex site. See letter dated March 8, 2012 
from Matthew Lakin, Manager, Air Quality Analysis Office, EPA Region 
IX to Mike Sword, Engineering Manager, Clark County DAQ.
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    Table 1 summarizes the site-specific annual fourth-high daily 
maximum 8-hour ozone concentrations and 3-year ozone design values for 
all monitoring sites within the Clark County 8-hour ozone nonattainment 
area for the period of 2009-2011. As shown in table 1, the design value 
for the 2009-2011 period was less than 0.084 ppm at all of the 
monitors. Therefore, we are proposing to determine, based on the 
complete, quality-assured data for 2009-2011, that the Clark County 8-
hour ozone nonattainment area has attained the 1997 8-hour ozone 
standard. There are ten ozone monitors currently operating in the 
nonattainment area. Preliminary SLAMS data for 2012 from these 
monitors, which are summarized in table 2, are also consistent with 
continued attainment.

    Table 1--Summary of Ambient Data Collected Within Clark County 8-Hour Ozone Nonattainment Area, 2009-2011
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                                                     2009 4th        2010 4th        2011 4th        2009-2011
             Monitor                 Site code        highest         highest         highest      average (ppm)
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Craig Road......................     32-003-0020           0.072             (*)             N/A             N/A
Apex............................     32-003-0022           0.070           0.068           0.070           0.069
Paul Meyer......................     32-003-0043           0.071           0.070           0.078           0.073
Walter Johnson..................     32-003-0071           0.074           0.073           0.077           0.074
Lone Mountain...................     32-003-0072           0.072             (*)             N/A             N/A
Palo Verde......................     32-003-0073           0.072           0.071           0.077           0.073
Joel Neal.......................     32-003-0075           0.074           0.074           0.077           0.075
Winterwood......................     32-003-0538           0.070           0.068           0.073           0.070
Jerome Mack **..................     32-003-9540             N/A             N/A           0.073             N/A
Boulder City....................     32-003-0601           0.071           0.069           0.070           0.070
Jean............................     32-003-1019           0.072           0.074           0.074           0.073

[[Page 67604]]

 
Orr.............................     32-003-1021           0.071             (*)             N/A             N/A
J.D. Smith......................     32-003-2002           0.072           0.068           0.072           0.070
----------------------------------------------------------------------------------------------------------------
* Monitor discontinued. N/A = not available.
** 2011 was the first full year of operation of the Jerome Mack ozone monitor.


 Table 2--Preliminary 4th High Daily Maximum 8-Hour Ozone Concentrations
                              for 2012 \a\
------------------------------------------------------------------------
                                                                   4th
                                                                 highest
                    Monitor                        Site code      value
                                                                  (ppm)
------------------------------------------------------------------------
Apex..........................................     32-003-0022     0.076
Paul Meyer....................................     32-003-0043     0.077
Walter Johnson................................     32-003-0071     0.075
Palo Verde....................................     32-003-0073     0.078
Joel Neal.....................................     32-003-0075     0.075
Winterwood....................................     32-003-0538     0.074
Jerome Mack...................................     32-003-0540     0.073
Boulder City..................................     32-003-0601     0.077
Jean..........................................     32-003-1019     0.077
J.D. Smith....................................     32-003-2002     0.076
------------------------------------------------------------------------
\a\ The data in this table are from AQS Preliminary Design Value Report.
  Report Date: Oct. 11, 2012. See docket.

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 Clark County with respect to 
ozone. 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 
Clark County 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 the Clark County ozone planning 
area 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 Clark County portion of the SIP that 
prevent redesignation of the Clark County 8-hour ozone nonattainment 
area for the 1997 8-hour ozone standard.\9\ Therefore, we propose to 
conclude that NDEP and Clark County have met all SIP requirements for 
Clark County applicable for purposes of redesignation under section 110 
of the CAA (General SIP Requirements).
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    \9\ Recently, EPA took final limited approval and limited 
disapproval on updated new source review (NSR) rules adopted by 
Clark County and submitted as a revision to the Nevada SIP (77 FR 
64039, October 18, 2012) and issued a partial approval and partial 
disapproval of Nevada's ``infrastructure'' SIP for the 1997 8-hour 
ozone NAAQS (77 FR 64737, October 23, 2012). While these two final 
rules are not full approvals, they do not represent an obstacle to 
redesignation of the Clark County 8-hour ozone nonattainment area 
because EPA's rationale for finding that the State has met the 
requirements of CAA section 107(d)(3)(E)(ii) and (v) does not rely 
on a fully-approved nonattainment NSR program, and because the 
``infrastructure'' SIP elements that EPA disapproved are not related 
to the nonattainment SIP requirements for the Clark County 8-hour 
ozone nonattainment area and thus are not relevant for the purposes 
of redesignation.
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2. Part D Requirements
a. Introduction
    The CAA contains two sets of provisions, subparts 1 and 2, that 
address planning and emission control requirements for ozone 
nonattainment areas. Both of these subparts are found in title I, part 
D of the CAA; sections 171-179 and sections 181-185, respectively. 
Subpart 1 contains general, less prescriptive requirements for all 
nonattainment areas of any pollutant, including ozone, governed by a 
NAAQS. Subpart 2 contains additional, more specific requirements for 
ozone nonattainment areas classified under subpart 2.
    The applicable subpart 1 requirements are contained in sections 
172(c)(1)-(9) and 176 of the CAA. Under subpart 1, with respect to the 
Clark County 8-hour ozone nonattainment area, the State of Nevada is 
required to submit SIP revisions that provide for:
     Implementation of all reasonably available control 
measures (RACM), including, at a minimum, reasonably available control 
technology for existing sources and attainment of the standard (section 
172(c)(1));
     Reasonable further progress (section 172(c)(2));

[[Page 67605]]

     A comprehensive, accurate, current inventory of actual 
emissions from all sources of the relevant pollutant or pollutants in 
the area (section 172(c)(3));
     Identification and quantification of the emissions, if 
any, of any such pollutants which will be allowed in accordance with 
section 173(a)(1)(B) (i.e., new or modified stationary sources located 
in established economic development zones) (section 172(c)(4));
     Permits for the construction and operation of new and 
modified major stationary sources in the nonattainment area (section 
172(c)(5));
     Enforceable emission limitations as may be necessary or 
appropriate to provide for attainment of such standard in such area by 
the applicable attainment date (section 172(c)(6));
     Compliance with section 110(a)(2) of the Act (section 
172(c)(7));
     Use of equivalent modeling emission inventory, and 
planning procedures if approved by EPA (section 172(c)(8));
     Contingency measures (section 172(c)(9)); and
     Interagency consultation and enforceability for the 
purposes of transportation conformity (section 176(c)(5) and 40 CFR 
51.390).
    As noted above, EPA determined that the Clark County 8-hour ozone 
nonattainment area attained the 1997 8-hour ozone NAAQS based on 2007-
2009 ozone data (76 FR 17343, March 29, 2011), and thereby suspended, 
under 40 CFR 51.918, the obligation on the State of Nevada to submit an 
attainment demonstration and associated reasonably available control 
measures (RACM), a reasonable further progress (RFP) plan, contingency 
measures and other planning requirements related to attainment of the 
1997 8-hour ozone NAAQS until such time as: the area is redesignated to 
attainment, at which time the requirements no longer apply; or EPA 
determines that the area has violated the 8-hour ozone NAAQS. As such, 
the State's compliance status with the attainment-related SIP 
requirements under subpart 1 is not relevant for the purposes of 
evaluating the State's redesignation request. 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) or 172(c)(8) (equivalent techniques).
    With respect to the requirements associated with subpart 2, we note 
that, as discussed in more detail above, the Clark County 8-hour ozone 
nonattainment area was initially designated nonattainment under subpart 
1 of the CAA, but was subsequently classified as marginal nonattainment 
for the 1997 8-hour ozone standard under subpart 2 of part D of the 
CAA. See 77 FR 28424 (May 14, 2012). The effective date of EPA's 
classification of the Clark County 8-hour ozone nonattainment area as 
marginal was June 13, 2012, and under the final May 14, 2012 subpart 2 
classifications rule, states have one year from the effective date of 
that final rule (i.e., June 13, 2013) to submit SIP revisions.
    NDEP has not submitted any SIP revisions for the Clark County 8-
hour ozone nonattainment area in response to the area's recent 
classification to marginal.\10\ However, EPA believes that this does 
not preclude this redesignation from being approved. This belief is 
based upon: (1) EPA's longstanding policy of evaluating requirements in 
accordance with the requirements due at the time redesignation request 
is submitted; and (2) consideration of the inequity of applying 
retroactively any requirements that might in the future be applied.
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    \10\ In any event, the State of Nevada would not be required to 
submit a SIP revision under section 182(a)(2)(A) to correct RACT 
rules for the Clark County 8-hour ozone nonattainment area because 
the area had not been identified by EPA under the pre-1990 CAA as an 
area that had RACT rule deficiencies. At that time, all of Clark 
County, including Las Vegas Valley, was designated as attainment for 
the then-current 1-hour ozone standard and had been so designated 
since 1986. See 51 FR 41788 (November 19, 1986). We also note that, 
for the purposes of meeting the SIP requirements for nonattainment 
areas for carbon monoxide, the State previously submitted, and EPA 
approved, SIP revisions that would meet the vehicle inspection and 
maintenance requirements under CAA section 182(a)(2)(B) for the 
Clark County 8-hour ozone nonattainment area, if those requirements 
were applicable for the purposes of redesignation. See at 69 FR 
56351 (September 21, 2004), 73 FR 38124 (July 3, 2008), and 74 FR 
3975 (January 22, 2009).
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    First, at the time the redesignation request was submitted (i.e., 
April 11, 2011), the Clark County 8-hour ozone nonattainment area was 
not classified under subpart 2, and thus, subpart 2 requirements were 
not yet due for this area. Under EPA's longstanding interpretation of 
section 107(d)(3)(E) of the CAA, to qualify for redesignation, states 
requesting redesignation to attainment must meet only the relevant SIP 
requirements that came due prior to the submittal of a complete 
redesignation request. See the Calcagni memo and also the September 17, 
1993, Michael Shapiro Memorandum (``State Implementation Plan (SIP) 
Requirements for Areas Submitting Requests for Redesignation to 
Attainment of the Ozone and Carbon Monoxide (CO) National Ambient Air 
Quality Standards (NAAQS) on or after November 15, 1992,'' Memorandum 
from Michael Shapiro, Acting Assistant Administrator for Air and 
Radiation), and 60 FR 12459, (March 7, 1995) (Redesignation of Detroit-
Ann Arbor, Michigan); Sierra Club v. EPA, 375 F.3d 537 (7th Cir. 2004) 
(upholding this interpretation); 68 FR 25418, 25424, 25427 (May 12, 
2003) (redesignation of St. Louis, Missouri).
    Moreover, it would be inequitable to retroactively apply any new 
SIP requirements that were not applicable at the time the request was 
submitted. The D.C. Circuit Court has recognized the inequity in such 
retroactive rulemaking (see Sierra Club v. Whitman 285 F. 3d 63 (D.C. 
Cir. 2002)), in which the court upheld a district court's ruling 
refusing to make retroactive an EPA determination of nonattainment that 
was past the statutory due date. Such a determination would have 
resulted in the imposition of additional requirements on the area. The 
court stated, ``[a]lthough EPA failed to make the nonattainment 
determination within the statutory frame, Sierra Club's proposed 
solution only makes the situation worse. Retroactive relief would 
likely impose large costs on the states, which would face fines and 
suits for not implementing air pollution prevention plans in 1997, even 
though they were not on notice at the time.'' Id. at 68. Similarly 
here, it would be unfair to penalize the Clark County 8-hour ozone 
nonattainment area by applying to it, for purposes of redesignation, 
additional SIP requirements under subpart 2 that were not in effect or 
yet due at the time it submitted its redesignation request, or the time 
that the Clark County 8-hour ozone nonattainment area attained the 
NAAQS.
    In the following paragraphs, we explain how the State has met the 
SIP revision requirements for those remaining requirements under part D 
that are not currently suspended or not otherwise applicable.
b. Emissions Inventory
    EPA regulations at 40 CFR 51.915 extend the SIP requirements under 
CAA sections 172(c)(3) to areas designated as nonattainment for the 
1997 8-hour ozone standard. CAA section 172(c)(3) requires States to 
submit a comprehensive, accurate, current inventory of actual VOC and 
NOX emissions for the baseline year from all sources within 
the nonattainment area. The inventory is to address actual VOC and 
NOX emissions during the ozone season, and all stationary 
(generally referring to larger stationary source or ``point'' sources), 
area (generally referring to smaller stationary and

[[Page 67606]]

fugitive (non-smokestack) sources), and mobile (on-road, nonroad, 
locomotive and aircraft) sources are to be included in the inventory.
    We interpret the Act such that the emission inventory requirements 
of section 172(a)(3) 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 Clark County Ozone Maintenance Plan and 
related VOC and NOX emission inventories and our proposed 
approval of NDEP's redesignation request would satisfy the requirements 
of sections 172(a)(3) for the purposes of redesignation of the Clark 
County 8-hour ozone nonattainment area to attainment for the 1997 8-
hour ozone NAAQS.
c. Permits for New and Modified Major Stationary Sources
    To meet the requirements of CAA section 172(c)(5), states must 
submit SIP revisions that meet the requirements under 40 CFR 51.165 
(``Permit requirements''), and EPA regulations at 40 CFR 51.914 extend 
the SIP requirements of 40 CFR 51.165 to areas designated as 
nonattainment for the 1997 8-hour ozone standard.
    Under 40 CFR 51.165, states are required 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.'' With respect to pollutants for which an area is 
designated as attainment or unclassifiable, states are required to 
submit SIP revisions that ensure that major new stationary sources and 
major modifications of existing stationary sources meet the Federal 
requirements for Prevention of Significant Deterioration'' (PSD), 
including application of ``best available control technology,'' for 
each applicable pollutant emitted in significant amounts, among other 
requirements.
    As noted above, under Nevada law, specific electric steam-
generating emission units (i.e., power plants) within Clark County are 
under NDEP jurisdiction. See Nevada Revised Statutes (NRS) section 
445B.500. Thus, state regulations govern air pollution permits issued 
by NDEP to those units. Clark County DAQ is responsible for all other 
stationary sources emissions units, and Clark County regulations govern 
air pollutant permits issued to them.
    Under the Clean Air Act Amendments of 1977, States with designated 
nonattainment areas were required to amend their NSR rules to impose 
LAER and offset requirements on new major sources and major 
modifications of nonattainment pollutants in nonattainment areas. As 
noted previously, under the 1977 Act Amendments, we designated Las 
Vegas Valley as a nonattainment area for photochemical oxidant, later 
changed to ozone. To address the nonattainment NSR requirements flowing 
from the 1977 Act Amendments, the State of Nevada amended its 
nonattainment NSR rules (Nevada Air Quality Regulations (NAQR) Article 
13), and NDEP submitted them to EPA for approval as part of the Nevada 
SIP. We approved the amended NSR rules in 1981. See 46 FR 21758 (April 
14, 1981). Under these EPA-approved rules, LAER and offsets have been 
required for new ``point sources'' that cause emissions greater than 
100 tons per year of ozone precursors in ozone nonattainment areas. In 
the 1980's EPA also approved Clark County NSR rules for Las Vegas 
Valley as meeting the related requirements under the 1977 Amended Act 
and EPA regulations.
    The 1990 Clean Air Act Amendments retained the core nonattainment 
NSR elements of LAER and offsets but added other requirements. To 
address the nonattainment designations of Las Vegas Valley for carbon 
monoxide and particulate matter for sources under NDEP jurisdiction and 
in lieu of amending the rules to meet the additional NSR requirements 
under the 1990 Act Amendments, the State of Nevada submitted a rule 
(Nevada Administrative Code (NAC) section 445B.22083) establishing a 
construction ban for new major sources and major modifications within 
the nonattainment area. NAC 445B.22083, with a limited exception, 
prohibits new power plants or major modifications to existing power 
plants under State jurisdiction within four hydrographic areas in Clark 
County, including Las Vegas Valley (hydrographic area No. 212). See 69 
FR 31056, 31059 (June 2, 2004) and 69 FR 54006, at 54017 (September 7, 
2004). We approved NAC 445B.22083 into the Nevada SIP most recently in 
2008. See 73 FR 20536 (April 16, 2008). However, the prohibition in NAC 
445B.22083 does not cover the entire Clark County 8-hour ozone 
nonattainment area, which includes the four hydrographic areas listed 
in NAC 445B.22083, but also includes all or portions of seven 
additional hydrographic areas in Clark County. See 40 CFR 81.329. Thus, 
the State of Nevada does not have a nonattainment NSR program meeting 
the requirements of 40 CFR 51.165 for those sources under NDEP 
jurisdiction within the Clark County 8-hour ozone nonattainment area.
    With respect to Clark County regulations, EPA recently finalized a 
limited approval and limited disapproval of updated Clark County rules 
governing NSR, including nonattainment NSR, but also PSD. See 77 FR 
64039 (October 18, 2012). Thus, Clark County does not have a 
nonattainment NSR program meeting the requirements of 40 CFR 51.165 for 
those sources under Clark County DAQ jurisdiction within the Clark 
County 8-hour ozone nonattainment area.
    We have determined, however, that, since PSD requirements \11\ will 
apply after redesignation, an area being redesignated to attainment 
need not comply with the requirement that a NSR program be approved 
prior to redesignation, provided that the state demonstrates 
maintenance of the NAAQS in the area without implementation of 
nonattainment NSR. A more detailed rationale for this view is described 
in a memorandum from Mary Nichols, Assistant Administrator for Air and 
Radiation, dated October 14, 1994, titled ``Part D New Source Review 
Requirements for Areas Requesting Redesignation to Attainment.'' See 
redesignation rulemakings for Detroit, Michigan (60 FR 12459, March 7, 
1995); Cleveland-Akron-Lorain, Ohio (61 FR 20458, 20469-20470, May 7, 
1996); Louisville, Kentucky (66 FR 53665, October 23, 2001); and, Grand 
Rapids, Michigan (61 FR 31831, June 21, 1996).
---------------------------------------------------------------------------

    \11\ PSD requirements control the growth of new source emissions 
in areas designated as attainment for a NAAQS.
---------------------------------------------------------------------------

    Based on our review of the Clark County Ozone Maintenance Plan, we 
conclude the maintenance demonstration included therein does not rely 
on implementation of nonattainment NSR because the plan applies 
standard growth factors to stationary source emissions and does not 
rely on NSR offsets to reduce the rate of increase in emissions over 
time from point sources. The Ozone

[[Page 67607]]

Maintenance Plan does include a line-item for emission reduction 
credits for VOC and NOX but adds them to future projected 
emissions rather than assuming that they would be used to reduce 
emissions growth from stationary sources. Therefore, EPA concludes that 
the State need not have a fully approved nonattainment NSR program as 
an applicable requirement for approval of the State's ozone 
redesignation request for the Clark County ozone planning area.
    Because the State's PSD program has been disapproved with respect 
to sources under NDEP jurisdiction, the Federal PSD requirements under 
40 CFR 52.21 will apply to new major sources or major modifications of 
ozone precursors under NDEP jurisdiction once the Clark County 8-hour 
ozone nonattainment area is redesignated to attainment. See 40 CFR 
52.1485(b). NDEP implements and enforces the Federal PSD regulations 
under a delegation agreement with EPA Region IX.
    With respect to stationary sources under Clark County DAQ 
jurisdiction, the County's PSD program will apply to ozone precursor 
emissions of new major sources or major modifications upon 
redesignation of the Clark County 8-hour ozone nonattainment area to 
attainment. We note that Clark County's PSD program is not fully 
approved, but the deficiencies that formed the basis for EPA's recent 
limited approval and limited disapproval action would not interfere 
with maintenance of the ozone standard for two reasons. First, the 
deficiencies that relate to ozone precursors are limited to a few 
definitions: ``allowable emissions,'' ``baseline actual emissions,'' 
``net emissions increase,'' and ``major modification.'' See 77 FR 
64039, at 64047 (October 18, 2012). Second, the limited disapproval 
triggered an obligation on EPA to promulgate a Federal implementation 
plan (FIP) to remedy the PSD deficiencies by November 19, 2014 unless 
NDEP submits, and EPA approves, amended Clark County rules that correct 
the deficiencies prior to that time. Thus, the overlap in time during 
which the Clark County 8-hour area would be redesignated to attainment 
but would not be subject to a fully-approved PSD program would be less 
than two years.
d. Compliance With Section 110(a)(2)
    Section 172(c)(7) requires the SIP to meet the applicable 
provisions of section 110(a)(2). As noted above, we conclude the Nevada 
SIP meets the requirements of section 110(a)(2) applicable for purposes 
of this redesignation.
e. Conformity Requirements
    Under section 176(c) of the Clean Air Act Amendments of 1990, 
States are required to establish criteria and 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).
    With respect to ``general conformity,'' we note that, 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. The State of Nevada is thus no longer required to submit a 
general conformity SIP for the Clark County 8-hour ozone planning area.
    Therefore, 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 the Clark County 8-hour ozone 
nonattainment area 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.

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. Under this criterion, the state 
must be able to reasonably attribute the improvement in air quality to 
emissions reductions which are permanent and enforceable. Attainment 
resulting from temporary reductions in emissions rates (e.g., reduced 
production or shutdown due to temporary adverse economic conditions) or 
unusually favorable meteorology would not qualify as an air quality 
improvement due to permanent and enforceable emission reductions.
    The Clark County Ozone Maintenance Plan credits the following 
control measures as providing the emissions reductions sufficient to 
attain the 1997 8-hour ozone NAAQS in the Clark County 8-hour ozone 
nonattainment area through year 2022: the Federal Tier 2 motor vehicle 
emissions standards; the Federal highway diesel rule; the Federal large 
nonroad diesel engines rule; the Federal nonroad spark-ignition engines 
and recreational engines standards; the Federal nonroad spark-ignition 
engines and equipment standard; the State's vehicle I/M program; and 
the County's NSR and stationary source prohibitory rules. As discussed 
above, the State's vehicle inspection and maintenance (I/M) program and 
the County's NSR rules and VOC-related prohibitory rules (such as 
section 52 (``Handling of Gasoline at Service Stations, Airports and 
Storage Tanks'')) have been approved into the SIP, and thus are 
federally enforceable.
    The Federal on-road and nonroad vehicle and engine standards cited 
above have 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 new Federal fuel standards cited above have 
resulted in more immediate emissions reductions of ozone precursors and 
provide for the use of advanced pollution control technology that would 
not otherwise be possible. The emissions reductions from

[[Page 67608]]

the Federal vehicle and fuel standards 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 and NONROAD emission factor model for nonroad 
vehicles.
    We note that some of the control measures cited in the Clark County 
Ozone Maintenance Plan provided emissions reductions since 2002, and 
thus, the improvement in air quality since 2002 may reasonably be 
attributed to them. For instance, the new Federal gasoline and diesel 
fuel standards have greatly lowered the allowable sulfur content of 
these fuels and have resulted in lower emissions from cars and trucks, 
particularly of sulfur dioxide, particulate matter, and NOX. 
The Clark County Ozone Maintenance Plan (see Figure 4-1 from the plan) 
illustrates the ambient ozone trend in the nonattainment area from 
2003-to 2009 and layers the sequence of Federal engine and fuel 
standards phase-in over that period to support the inference that the 
standards have contributed to the declining trend in ambient ozone 
concentrations.
    A rough sense of the effectiveness of the control measures to 
reduce VOC and NOX emissions can be gained by a comparison 
between area-wide emissions in 2002 (a nonattainment year) with those 
in 2008 (an attainment year). In 2002, area-wide VOC and NOX 
emissions in the Clark County 8-hour ozone nonattainment area were 
estimated to be approximately 318 and 279 tons per day (summer average 
day), respectively, and in 2008, despite an increase in population and 
vehicle-miles-traveled (VMT) of approximately 27% and 48%, 
respectively, area-wide emissions dropped significantly (to 302 tons 
per day of VOC and 164 tons per day of NOX).\12\
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    \12\ See table 4-1, and appendix A, table 3-1, from Clark County 
DAQ's 8-Hour Ozone Early Progress Plan for Clark County, Nevada 
(June 2008) and tables 4-1, 6-1, 6-2, and 6-3 from the Clark County 
Ozone Maintenance Plan.
---------------------------------------------------------------------------

    With respect to the connection between the emissions reductions and 
the improvement in air quality, we also conclude that the air quality 
improvement in the Clark County 8-hour ozone nonattainment area since 
2002 is not the result of a local economic downturn or unusual or 
extreme weather patterns. To draw this conclusion, we reviewed 
temperature and precipitation data for Las Vegas \13\ and did not 
observe any anomaly over the period from 2002 relative to long-term 
averages. We do recognize that a significant economic slowdown occurred 
nationally starting in 2008, and that the Las Vegas metropolitan area 
was more significantly affected than most other areas, but we note that 
the downward ozone trend had already been established before that time 
(see Figure 4-1 on page 4-8 of the Ozone Maintenance Plan).
---------------------------------------------------------------------------

    \13\ Our reference for climate data is ``Climate of Las Vegas, 
Nevada,'' by Andrew Gorelow and Chris Stachelski, updated October 
2012, as well as the climate data discussed on pages 4-2 and 4-3 of 
the Ozone Maintenance Plan.
---------------------------------------------------------------------------

    Thus, we find that the improvement in air quality in the Clark 
County 8-hour ozone nonattainment area is the result of permanent and 
enforceable emissions reductions from a combination of the Federal 
vehicle and fuel measures 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 Clark County 
Ozone Maintenance Plan because we believe that it meets the 
requirements of CAA section 175A.
1. Attainment Inventory
    A maintenance plan for the 1997 8-hour ozone standard must include 
an inventory of emissions of ozone precursors (VOC and NOX) 
in the area to identify a level of emissions that are sufficient to 
attain the 1997 8-hour ozone NAAQS. This inventory must 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 must also be comprehensive, including 
emissions from stationary point sources, area sources, nonroad mobile 
sources, and on-road mobile sources, and must be based on actual 
``ozone season data'' (i.e., summertime) emissions.
    Clark County DAQ selected year 2008 as the year for the attainment 
inventory in the Clark County Ozone Maintenance Plan. Year 2008 is one 
of the years of the three-year period (2007-2009) on which EPA made an 
attainment determination for the Clark County 8-hour ozone 
nonattainment area in 2011. See 76 FR 17343 (March 29, 2011). The 
attainment inventory will generally be the actual inventory during the 
time period the area attained the standard. Thus, Clark County DAQ's 
selection of 2008 for the attainment inventory is acceptable.
    Based on our review of the Clark County Ozone Maintenance Plan, we 
find that the emissions inventories in the plan are comprehensive in 
that they include estimates of VOC and NOX emissions from 
all of the relevant source categories, which the plan divides among 
point sources,\14\ nonpoint sources,\15\ commercial aviation, Federal 
aviation (i.e., Nellis Air Force Base), on-road mobile, nonroad mobile, 
and biogenic \16\ sources. See table 6-2 and pages 6-2 through 6-5 in 
the Ozone Maintenance Plan. Appendix A to the Ozone Maintenance Plan 
contains source-specific descriptions of emission calculation 
procedures and sources of input data.
---------------------------------------------------------------------------

    \14\ The Ozone Maintenance Plan uses the term, ``point 
sources,'' to refer to those stationary source facilities that are 
required to report their emissions to Clark County DAQ or NDEP.
    \15\ The Ozone Maintenance Plan uses the term, ``nonpoint 
sources,'' to refer to those stationary and area sources that fall 
below point source reporting levels and that are too numerous or 
small to identify individually.
    \16\ For the Ozone Maintenance Plan, ``biogenic sources'' 
include agricultural crops; lawn grass; forests that produce 
isoprene, monoterpene, alpha-pinene, and other VOC emissions; and 
soils that generate trace amounts of NOX.
---------------------------------------------------------------------------

    For point sources, Clark County DAQ based the inventory estimates 
on source-reported actual 2008 emissions data but adjusted the reported 
values to reflect a typical summer day at each emissions unit within 
the source facilities based on information provided by the

[[Page 67609]]

facilities. For nonpoint sources, Clark County DAQ used several methods 
to estimate area source activity levels and emissions, including 
applying local activity levels, apportioning national or statewide 
activity levels to the local level, applying per capita emission 
factors considering county-specific populations and using specific 
method abstracts detailed within the submittal. The documentation 
supplied in the emissions inventory submittal (i.e., appendix A to the 
Ozone Maintenance Plan) shows how the specific emissions were 
calculated for each area source category.
    With respect to most nonroad mobile sources, Clark County DAQ used 
EPA's nonroad emissions model NONROAD2008a, the current version of the 
model at the time the plan was created. The model includes both 
emissions factors and default county level population and activity 
data. The model estimates both emissions factors and emissions. This 
includes more than 80 basic and 260 specific types of non-road 
equipment, and further stratifies equipment by horsepower rating and 
fuel type. The model has default estimates, variables and factors used 
in the calculations. No local data sets were available for Clark 
County, therefore only model defaults were used.
    With respect to commercial and Federal aviation sources, Clark 
County DAQ relied on airport-specific emissions inventory information 
provided by the Clark County Aviation Department for the five 
commercial airports located within the nonattainment area (McCarran 
International Airport, North Las Vegas Airport, Henderson Executive 
Airport, Jean Airport, and Perkins Field Airport) and information 
provided by the U.S. Air Force for Nellis Air Force Base. Airport 
support equipment and airport-related stationary source emissions were 
included in the airport-specific inventories rather than in the general 
source categories such as point sources or nonroad mobile. Locomotive 
emissions were estimated by Clark County DAQ based on fuel consumption 
within the nonattainment area by the Union Pacific Railroad and 
included in the aggregate emissions estimates for ``nonroad mobile.'' 
To estimate biogenic emissions, Clark County DAQ used the Model of 
Emissions of Gasses and Aerosols from Nature (MEGAN) estimates, 
measured emission factors, and species information from completed 
surveys.
    The on-road mobile source emissions estimates in the Ozone 
Maintenance Plan were prepared by Clark County DAQ using the CONCEPT MV 
emissions model,\17\ EPA's MOBILE6.2 emissions factors, the Regional 
Transportation Commission of Southern Nevada's (RTC's) transportation 
demand modeling results,\18\ and Highway Performance Monitoring System 
(HPMS) data from the Nevada Department of Transportation.
---------------------------------------------------------------------------

    \17\ ``CONCEPT'' refers to the CONsolidated Community Emissions 
Processor Tool (CONCEPT,) and ``MV'' refers to the motor vehicle 
module of the CONCEPT model.
    \18\ One of the principal sources of transportation data used to 
develop the emissions inventories in the Ozone Maintenance Plan is 
the Regional Transportation Plan 2009-2030, approved by the RTC in 
November 2008. See page 6-1 of the maintenance plan.
---------------------------------------------------------------------------

    MOBILE6.2 estimates emissions by vehicle class, and provides 
emissions factors for exhaust emissions; evaporative emissions; and 
brake and tire wear emissions. There are a total of 28 vehicle classes 
used in MOBILE6.2. For the Ozone Maintenance Plan, Clark County DAQ 
aggregated the emissions factors calculated from MOBILE6.2 into eight 
vehicle classes, which are the same as used in MOBILE5. The VMT was 
adjusted by comparisons to observed vehicle counts by facility types, 
by using HPMS adjustment factors and to account for additional transit 
vehicles. The CONCEPT MV model processes detailed inputs (e.g., VMT mix 
varying by hour of day, day of week, and month of year) and adjusts 
speeds to account for congestion based on transportation demand 
modeling outputs. For areas outside of the Las Vegas Valley, county 
level VMT estimates based on HPMS data was used and no reductions 
associated with the State's motor vehicle inspection and maintenance 
(I/M) program were included since vehicles in the rural portions of the 
county are not required to participate in the program.
    The on-road emissions estimates for the Ozone Maintenance Plan 
assumed the implementation of the Federal heavy-duty diesel rule, 
limits to Reid Vapor Pressure (RVP) of 9 pounds per square inch (psi) 
with a 1.0 psi waiver for ethanol-blended fuels \19\ and the phase-in 
of tier 2 motor vehicle emission standards, and the operation of an 
enhanced vehicle I/M program in the urban areas of Clark County.
---------------------------------------------------------------------------

    \19\ The market share of ethanol blend in summertime is assumed 
to be approximately 63% for 2008 and 100% for 2015 and 2022.
---------------------------------------------------------------------------

    Table 3 presents the VOC and NOX emissions estimates 
contained in the Ozone Maintenance Plan for 2008 and also presents the 
plan's projected emissions inventories of ozone precursors in an 
interim year (2015) and the maintenance plan's horizon year (2022).\20\ 
Based on the estimates in Table 3, on-road emissions sources accounted 
for approximately 22% of the VOC and 42% of the NOX 
emissions generated within the 8-hour ozone nonattainment area in 2008. 
Nonroad sources (including nonroad equipment, airports, and 
locomotives) accounted for approximately 15% and 34% of the VOC and 
NOX inventory, respectively. Point and area source emissions 
accounted for approximately 19% and 21% of the VOC and NOX 
inventory, respectively, while biogenic emissions contributed 44% of 
the VOC inventory but little (3%) to the overall NOX 
inventory.
---------------------------------------------------------------------------

    \20\ The emissions inventories reflect county-wide emissions 
which include both the nonattainment area portion of the county and 
the portion of the county designated as ``unclassifiable/
attainment'' for the 1997 8-hour ozone NAAQS. County-wide emissions 
are acceptable to characterize emissions within the Clark County 
ozone nonattainment area because over 95% of the population of the 
county resides in the nonattainment area.

                                  Table 3--2008 and Projected 2015 and 2022 VOC and NOX Emissions Total Daily Emissions
                                                       (Tons per day, average summer weekday) \a\
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                             2008                   2015                    2022
                Emission source                               Category             ---------------------------------------------------------------------
                                                                                        VOC        NOX         VOC         NOX         VOC        NOX
--------------------------------------------------------------------------------------------------------------------------------------------------------
Point..........................................  Clark County Point...............         1           12         1          12           1           12
                                                 Projected Power Plant............         0            0       < 0.5         3         < 0.5          3
                                                 Clark County NDEP Point..........       < 0.5         17       < 0.5        17         < 0.5         17
Airports.......................................  Clark County DOA.................         3           11         3          15           3           17
                                                 Ivanpah Airport..................         0            0       < 0.5       < 0.5         1           11
Nellis AFB.....................................  Nellis AFB.......................         1            1         1           2           1            2

[[Page 67610]]

 
Nonpoint Sources...............................  Nonpoint Sources.................        57            5        66           6          76            6
Locomotive.....................................  Locomotive.......................       < 0.5          2       < 0.5         2         < 0.5          2
On-road Mobile.................................  On-road Mobile...................        65           68        45          35          37           23
Nonroad Mobile.................................  Nonroad Mobile...................        43           41        32          28          30           18
Biogenic.......................................  Biogenic.........................       132            5       132           5         132            5
Banked Emission Reduction Credits (ERCs........  DAQ ERC Bank.....................         0            0       < 0.5         1         < 0.5          1
                                                 ERCs from Mohave Generating......         0            0       < 0.5        20         < 0.5         20
                                                 ERCs from Reid-Gardner...........         0            0         0           2           0            2
                                                                                   ---------------------------------------------------------------------
    Total......................................  .................................       302          164       282         146         282          139
--------------------------------------------------------------------------------------------------------------------------------------------------------
\a\ Derived from table 1-1 of appendix A to the Ozone Maintenance Plan. For the purposes of this table, the estimates contained in the maintenance plan
  have been rounded to the nearest whole number (except for values greater than zero but less than 0.5, which are shown as ``< 0.5''). The sum of the
  values in each column may not equal the total shown due to rounding. DOA = Clark County Department of Aviation; AFB = Air Force Base; and ERCs =
  emission reduction credits.

    Based on our review of the emissions inventories (and related 
documentation) from the Ozone Maintenance Plan, we find that the 
inventories for 2008 are comprehensive, that the methods and 
assumptions used by Clark County DAQ to develop the 2008 emission 
inventory are reasonable, and that the inventories reasonably estimate 
actual ozone season emissions in an attainment year. Moreover, we find 
that the 2008 emissions inventories in the Ozone Maintenance Plan 
reflect the latest planning assumptions and emissions models available 
at the time the plan was developed, and provide a comprehensive and 
reasonably accurate basis upon which to forecast ozone precursor 
emissions for years 2015 and 2022.
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 ozone 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. The 
Clark County 8-hour ozone nonattainment area was not required to submit 
a modeled attainment demonstration, and thus, the Clark County Ozone 
Maintenance Plan may demonstrate maintenance based on a comparison of 
existing and future emissions of ozone precursors.\21\
---------------------------------------------------------------------------

    \21\ A maintenance demonstration need not be based on ozone 
modeling. See Wall v. EPA, 375 F.3d 537 (7th Cir. 2004). See also 66 
FR 53094, 53099-53100 (October 19, 2001), and 68 FR 25413, 25430-
25432 (May 12, 2003).
---------------------------------------------------------------------------

    Clark County DAQ used projected emissions \22\ for point and non-
point sources from calendar years 2008 and 2018 to back calculate the 
growth factors for all ozone precursor emissions for both inventory 
years. The derived growth factors were then mathematically extrapolated 
to account for a 14-year (2008 through 2022) spread. These 2022 growth 
factors were then multiplied by the 2008 actual emissions to produce 
the 2022 projected point source emissions. An interim year (2015) 
projected emissions inventory is also included. The 2015 emissions were 
calculated using half of the growth value of the 2022 projections. 
Corrections for rule effectiveness were not applied to these projected 
emissions. On-road emissions were estimated for the 2008 base year and 
for projection years 2015 and 2022 and reflect a 26% increase in VMT 
from 2008 to 2015 and a 63% increase in VMT from 2008 to 2022 based on 
RTC projections. See table 6-1 in the Ozone Maintenance Plan.
---------------------------------------------------------------------------

    \22\ The projected emissions were obtained from the 2005 Clark 
County Consolidated Emission Inventory Report (Environ, May 31, 
2007, Appendix A).
---------------------------------------------------------------------------

    In addition to accounting for area-wide growth trends, Clark County 
DAQ added emissions from specific projects that are expected to become 
operational during the maintenance period, including the Nellis Air 
Force Base F-35 beddown project, a new power plant, a new airport 
(Ivanpah), and new heliport (Sloan), in the future-year emissions 
inventories, and also added in emissions reduction credits (ERCs) from 
certain stationary sources in the event that the ERCs are used for the 
purposes of issuing permits for new or modified stationary sources in 
the air quality planning area. We have reviewed the methods and 
assumptions, as described in connection with the attainment inventory, 
that Clark County DAQ used to project emissions to 2015 and 2022 for 
the various source categories and find them to be reasonable.
    Table 3 compares the VOC and NOX emissions estimated for 
the Clark County 8-hour ozone nonattainment area for 2008 with those 
for 2015 and 2022 by source category. The projected VOC and 
NOX emissions show that VOC and NOX emissions 
would remain well below the attainment levels throughout the 10-year 
maintenance period and thereby adequately demonstrating maintenance 
through that period.
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, 
ozone is currently monitored by Clark County DAQ at ten sites within 
the Clark County 8-hour ozone nonattainment area. In the Ozone 
Maintenance Plan (see page 6-11 of the plan), Clark County DAQ 
indicates its intention to continue operation of an air quality 
monitoring network to verify continued attainment of the 1997 8-hour 
ozone NAAQS.\23\ The Clark County Ozone

[[Page 67611]]

Maintenance Plan also notes that Clark County DAQ's SLAMS air quality 
monitoring system (which includes ambient ozone monitoring) will be 
reviewed annually pursuant to 40 CFR 58.20(d) to determine whether the 
system continues to meet the applicable monitoring objectives.\24\ We 
find the County's commitment for continued ambient ozone monitoring as 
set forth in the Ozone Maintenance Plan to be acceptable.
---------------------------------------------------------------------------

    \23\ Although the Ozone Maintenance Plan is not explicit in this 
regard, we presume that Clark County DAQ's intention to continue 
operation of a monitoring network means that the agency intends to 
do so consistent with EPA's monitoring requirements in 40 CFR part 
58 (``Ambient Air Quality Surveillance'').
    \24\ EPA's requirements for annual review of monitoring networks 
are no longer codified at 40 CFR 58.20(d), but are now found at 40 
CFR 58.10.
---------------------------------------------------------------------------

4. Verification of Continued Attainment
    NDEP and the Clark County Board of County Commissioners have the 
legal authority to implement and enforce the requirements of the Ozone 
Maintenance Plan. This includes the authority to adopt, implement and 
enforce any emission control contingency measures determined to be 
necessary to correct ozone NAAQS violations. To verify continued 
attainment, Clark County DAQ commits in the Ozone Maintenance Plan to 
the continued operation of an ozone monitoring network that meets EPA 
ambient air quality surveillance requirements.
    Second, the transportation conformity process, which would require 
a comparison of on-road motor vehicle emissions that would occur under 
new or amended regional transportation plans and programs with the 
MVEBs in the Ozone Maintenance Plan, represents another means by which 
to verify continued attainment of the 1997 8-hour ozone NAAQS in the 
Clark County 8-hour ozone area given the relative importance of motor 
vehicle emissions to the overall emissions inventories of ozone 
precursors. See page 6-13 of the Ozone Maintenance Plan. Lastly, while 
not cited in the plan, NDEP and Clark County DAQ must inventory 
emissions sources and report to EPA on a periodic basis under 40 CFR 
part 51, subpart A (``Air Emissions Reporting Requirements''). These 
emissions inventory updates will provide a third means with which to 
track emissions in the area relative to those projected in the 
maintenance plan and thereby verify continued attainment of the NAAQS. 
These methods are sufficient for the purpose of verifying continued 
attainment.
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.
    As required by section 175A of the CAA, Clark County DAQ has 
adopted a contingency plan to address possible future ozone air quality 
problems. See section 6.8 of the maintenance plan. Clark County DAQ 
commits to examining ambient air quality data within 30 days of 
collection to determine if the ozone NAAQS has been exceeded. The 
contingency plan will be triggered 60 days after Clark County DAQ 
confirms a violation of the 1997 8-hour ozone NAAQS (i.e., a design 
value equal to or greater than 0.085 ppm). Within 45 days of the 
trigger date, Clark County will notify EPA that it is evaluating 
potential contingency measures. Within 90 days of that notification, 
Clark County will send a report to EPA and then will initiate a public 
process to consider the recommended contingency measures, including 
soliciting stakeholder involvement and holding public hearings. The 
necessary emission control measures will be adopted and implemented no 
later than 18 months after the information report is submitted to EPA.
    Contingency measures contained in the maintenance plan are those 
emission controls or other measures that Clark County, the Nevada State 
Board of Agriculture, and/or the Nevada State Environmental Commission 
choose to adopt and implement in response to the contingency trigger. 
The contingency plan in the Ozone Maintenance Plan lists the following 
potential contingency measures that will be considered for adoption and 
implementation by the applicable State or County agency, but the plan 
indicates that the list is not to be considered exclusive:
     Reid vapor pressure reduction (i.e., in gasoline sold 
during the summer ozone season; would need to be adopted and 
implemented by the Nevada State Board of Agriculture);
     Inspection/maintenance program changes and additions 
(e.g., lowering the cutpoints for VOCs and NOX applicable to 
pre-1996 vehicles; would need to be adopted and implemented by the 
State Environmental Commission and/or the State Department of Motor 
Vehicles);
     Consumer and commercial products (Clark County would be 
responsible for adoption and implementation);
     Architectural surface coatings (Clark County would be 
responsible for adoption and implementation);
     Lawn and garden equipment use (Clark County would be 
responsible for adoption and implementation); and
     Establish/enhance trip reduction programs (Clark County 
and the RTC would be responsible for adoption and implementation).
    Upon our review of the plan, as summarized above, we find that the 
contingency provisions of the Ozone 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 the contingency provisions of the Clark County Ozone Maintenance 
Plan are adequate to ensure prompt correction of a violation and 
therefore comply with section 175A(d) of the Act.
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 Clark County Ozone Maintenance 
Plan provides that Clark County commits to prepare and submit a revised 
maintenance plan eight years after redesignation to attainment. See 
page 6-13 of the Ozone 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

[[Page 67612]]

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 VOC and NOX emissions allowed in the 
last year of the maintenance period, i.e., the motor vehicle emissions 
budgets (MVEBs). (MVEBs may also be specified for additional years 
during the maintenance period.) The MVEBs serve as a ceiling on 
emissions that would result from an area's planned transportation 
system. The MVEB concept is further explained in the preamble to the 
November 24, 1993, transportation conformity rule (58 FR 62188). The 
preamble describes how to establish MVEBs in the SIP and how to revise 
the MVEBs if needed.
    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.
    EPA's process for determining adequacy of a MVEB consists of three 
basic steps: (1) Providing public notification of a SIP submission; (2) 
providing the public the opportunity to comment on the MVEB during a 
public comment period; and, (3) making a finding of adequacy. The 
process for determining the adequacy of a submitted MVEB is codified at 
40 CFR 93.118.
    The Clark County Ozone Maintenance Plan submitted by NDEP for Clark 
County, contains new VOC and NOX MVEBs for Clark County for 
2008, 2015, and 2022. The availability of the SIP submission with MVEBs 
was announced for public comment on EPA's Adequacy Web site on June 14, 
2011, at: http://www.epa.gov/otaq/stateresources/tansconf/currsips.htm, 
which provided a 30-day public comment period. The comment period for 
this notification ended on July 14, 2011, and EPA received no comments 
from the public. Note, however, that a second mechanism is also 
provided for EPA review and public comment on MVEBs, as described in 40 
CFR 93.118(f)(2). This mechanism provides for EPA's review of the 
adequacy of an implementation plan MVEB simultaneously with its review 
and approval and disapproval of the implementation plan itself. In this 
action, EPA used the web notification discussed above to solicit public 
comments on the adequacy of Clark County's MVEBs, but is taking comment 
on the approvability of the submitted MVEBs through this proposed rule.
    Clark County's ozone maintenance plan contains VOC and 
NOX MVEBs for 2008, 2015 and 2022. Any and all comments on 
the approvability of the MVEBs should be submitted during the comment 
period stated in the DATES section of this document.
    EPA proposes to approve 2008, 2015, and 2022 MVEBs in the Clark 
County Ozone Maintenance Plan for transportation conformity purposes in 
the final rulemaking on Clark County's ozone redesignation request. If 
EPA approves the MVEBs in the final rulemaking action, the new MVEBs 
must be used in future transportation conformity determinations for 
Clark County. The new MVEBs, if approved in the final rulemaking, will 
be effective on the date of EPA's final rulemaking in the Federal 
Register. The existing 2008 VOC and NOX MVEBs from the Clark 
County EPP, which EPA found adequate in 2009, will be replaced by these 
budgets. The applicable VOC and NOX MVEBs for the Clark 
County ozone nonattainment area are defined in table 4.

   Table 4--Motor Vehicle Emissions Budgets in the Clark County Ozone
                           Maintenance Plan a
------------------------------------------------------------------------
                                    VOC (tpd, average  NOX (tpd, average
            Budget year              summer weekday)    summer weekday)
------------------------------------------------------------------------
2008..............................              65.08              68.46
2015..............................              45.32              34.69
2022..............................              36.71              23.15
------------------------------------------------------------------------
\a\ From Table 7-1 (page 7-1) of the Ozone Maintenance Plan.

    The MVEBs are the on-road mobile source VOC and NOX 
emissions for Clark County for 2008, 2015 and 2022. The MVEBs are 
compatible with the 2008, 2015, and 2022 on-road mobile source VOC and 
NOX emissions included in Clark County's 2008, 2015, and 
2022 VOC and NOX emission inventories, as summarized above 
in table 3. The derivation of the MVEBs is thoroughly discussed in 
appendix A, chapter 7 of Clark County's Ozone Maintenance Plan. Updated 
vehicle miles traveled (VMT) data from the Regional Transportation 
Commission's TRANSCAD transportation demand model was adjusted with 
Highway Performance Monitoring System (HPMS) data and then combined 
with emission factors from MOBILE6 to estimate ozone precursor 
emissions.
    We note that the MVEBs in the Ozone Maintenance Plan for 2008 
differ from those contained for that same year in the Clark County 
Ozone EPP, but Clark County DAQ has explained the differences stem not 
from a different approach but from changes with regard to the fuel 
parameters and updated vehicle activity data for 2008. Specifically, 
the MOBILE input files used for the Ozone Maintenance Plan were updated 
to show the use of ethanol in summertime with a 1.0 psi waiver, 
resulting in higher VOC emissions, and the VMT estimates for 2008 were 
adjusted downwards to reflect the latest transportation data from RTC. 
The net effect of these changes resulted in higher VOC emissions but 
lower NOX emissions for 2008 relative to the corresponding 
estimates in the Clark County Ozone EPP.
    EPA is proposing to approve the MVEBs for 2008, 2015 and 2022 as 
part of our approval of Clark County's Ozone Maintenance Plan. EPA has 
determined that the MVEB emission targets are consistent with emission 
control measures in the SIP and that Clark County can maintain 
attainment of the 1997 8-hour ozone NAAQS. The details of EPA's 
evaluation of the MVEBs for compliance with the budget adequacy 
criteria of 40 CFR 93.118(e) are provided

[[Page 67613]]

in a separate memorandum \25\ included in the docket of this 
rulemaking.
---------------------------------------------------------------------------

    \25\ See EPA memorandum dated October 15, 2012 titled, 
``Adequacy Documentation for Motor Vehicle Emission Budgets in April 
2011 Clark County Ozone Maintenance State Implementation Plan.''
---------------------------------------------------------------------------

VI. Proposed Action and Request for Public Comment

    Under CAA section 110(k)(3), and for the reasons set forth above, 
EPA is proposing to approve NDEP's submittal dated April 11, 2011 of 
Clark County's Ozone Redesignation Request and Maintenance Plan (March 
2011) (``Clark County Ozone Maintenance Plan'') as a revision to the 
Nevada state implementation plan (SIP). In connection with the Clark 
County Ozone Maintenance Plan, EPA finds that the maintenance 
demonstration showing how the area will continue to attain the 1997 8-
hour ozone NAAQS for 10 years beyond redesignation (i.e., through 2022) 
and the contingency provisions describing the actions that Clark County 
will take in the event of a future monitored violation meet all 
applicable requirements for maintenance plans and related contingency 
provisions in CAA section 175A. EPA is also proposing to approve the 
motor vehicle emissions budgets (MVEBs) in the Clark County Ozone 
Maintenance Plan (shown in table 4 of this document) because we find 
they meet the applicable transportation conformity requirements under 
40 CFR 93.118(e).
    Second, under CAA section 107(d)(3)(D), we are proposing to approve 
NDEP's request, which accompanied the submitted of the maintenance 
plan, to redesignate the Clark County 8-hour ozone nonattainment area 
to attainment for the 1997 8-hour ozone NAAQS. We are doing so based on 
our conclusion that the area has met the five criteria for 
redesignation under CAA section 107(d)(3)(E). Our conclusion in this 
regard is in turn based on our proposed determination that the area has 
attained the 1997 8-hour ozone NAAQS, that relevant portions of the 
Nevada SIP are fully approved, that the improvement in air quality is 
due to permanent and enforceable reductions in emissions, that Nevada 
has met all requirements applicable to the Clark County 8-hour ozone 
nonattainment area with respect to section 110 and part D of the CAA, 
and based on our proposed approval as part of this action of the Clark 
County Ozone Maintenance Plan.
    EPA is soliciting public comments on the issues discussed in this 
document or on other relevant matters. We will accept comments from the 
public on this proposal for the next 30 days. We will consider these 
comments before taking final action.

VII. 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. 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 by State law. 
For these reasons, these proposed actions:
     Are not a ``significant regulatory action'' subject to 
review by the Office of Management and Budget under Executive Order 
12866 (58 FR 51735, October 4, 1993);
     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 CAA; and
     Do not provide EPA with the discretionary authority to 
address disproportionate human health or environmental effects with 
practical, appropriate, 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 the Clark County 8-hour ozone nonattainment area.

List of Subjects

40 CFR Part 52

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

40 CFR Part 81

    Environmental protection, Air pollution control, National parks, 
Wilderness areas.

    Dated: November 2, 2012.
Jared Blumenfeld,
Regional Administrator, Region IX.
[FR Doc. 2012-27562 Filed 11-9-12; 8:45 am]
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