Document ID: EPA-R09-OAR-2021-0242-0028
Agency: epa
Document Type: Proposed Rule
Title: Air Quality State Implementation Plans; Approvals and Promulgations: Nevada, Las Vegas Valley; Second 10-Year Carbon Monoxide Limited Maintenance Plan
Posted Date: 2021-08-02T04:00Z

[Federal Register Volume 86, Number 145 (Monday, August 2, 2021)]
[Proposed Rules]
[Pages 41416-41421]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2021-16453]

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 52

[EPA-R09-OAR-2021-0242; FRL-8725-01-R9]

Air Plan Approval; Nevada, Las Vegas Valley; Second 10-Year 
Carbon Monoxide Limited Maintenance Plan

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.

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SUMMARY: The Environmental Protection Agency (EPA) is proposing to 
approve a Nevada State Implementation Plan (SIP) revision submitted by 
the Nevada Department of Environmental Protection (NDEP). On September 
27, 2010, the EPA redesignated the Las Vegas Valley area from 
nonattainment to attainment for the carbon monoxide (CO) national 
ambient air quality standard (NAAQS or ``standard'') and approved the 
State's CO maintenance plan ensuring the area would maintain the NAAQS 
for ten years through 2020. On June 18, 2019, NDEP submitted to the EPA 
a second 10-year limited maintenance plan (LMP) for the Las Vegas 
Valley area for the CO NAAQS. The LMP addresses maintenance of the CO 
NAAQS for a second 10-year period ending in 2030.

DATES: Any comments must arrive by September 1, 2021.

ADDRESSES: Submit your comments, identified by Docket ID No. EPA-R09-
OAR-2021-0166 at https://www.regulations.gov. For comments submitted at 
Regulations.gov, follow the online instructions for submitting 
comments. Once submitted, comments cannot be edited or removed from 
Regulations.gov. The EPA may publish any comment received to its public 
docket. Do not submit electronically any information you consider to be 
Confidential Business Information (CBI) or other information whose 
disclosure is restricted by statute. Multimedia submissions (audio, 
video, etc.) must be accompanied by a written comment. The written 
comment is considered the official comment and should include 
discussion of all points you wish to make. The EPA will generally not 
consider comments or comment contents located outside of the primary 
submission (i.e., on the web, cloud, or other file sharing system). For 
additional submission methods, please contact the person identified in 
the FOR FURTHER INFORMATION CONTACT section. For the full EPA public 
comment policy, information about CBI or multimedia submissions, and 
general guidance on making effective comments, please visit

[[Page 41417]]

https://www.epa.gov/dockets/commenting-epa-dockets. If you need 
assistance in a language other than English or if you are a person with 
disabilities who needs a reasonable accommodation at no cost to you, 
please contact the person identified in the FOR FURTHER INFORMATION 
CONTACT section.

FOR FURTHER INFORMATION CONTACT: Jonathan Szeto, Air Planning Office 
(AIR-2), EPA Region IX, (415) 947-4278, szeto.jonathan@epa.gov.

SUPPLEMENTARY INFORMATION: Throughout this document, ``we,'' ``us,'' 
and ``our'' refer to the EPA.

Table of Contents

I. Background
II. Nevada's SIP Submittal
III. The EPA's Evaluation of Nevada's SIP Submittal
    A. Procedural Requirements
    B. LMP Requirements
IV. Transportation Conformity
V. Proposed Action and Public Comment
VI. Statutory and Executive Order Reviews

I. Background

    Carbon monoxide is a colorless, odorless gas that is generally 
emitted from the incomplete combustion of carbon-containing fuels. The 
largest sources of CO in ambient environments are cars, trucks, and 
other vehicles and machineries that burn fossil fuels. Inhalation of CO 
can impair oxygen delivery to vital organs and tissues. Those with pre-
existing heart disease or other conditions that make one unable to 
compensate for tissue hypoxia are particularly vulnerable to the 
cardiovascular effects of ambient CO, especially during exercise or 
when under increased stress. At high levels, CO exposure can also lead 
to dizziness, confusion, and unconsciousness.\1\
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    \1\ 76 FR 54294 (August 31, 2011).
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    In 1971 the EPA established primary and secondary NAAQS for CO at 9 
parts per million (ppm), averaged over an 8-hour period, and at 35 ppm, 
averaged over a 1-hour period.\2\ On September 13, 1985, the EPA 
retained the primary standards without revision and revoked the 
secondary standards.\3\ The EPA retained the primary standards without 
revision again in both 1994 \4\ and 2011.\5\ The EPA retained the 
primary standards based on scientific evidence demonstrating that the 
existing standards are requisite to protect public health with an 
adequate margin of safety. The EPA also found that analysis of both the 
non-climate and climate welfare effects of CO are insufficient to 
provide support for a secondary standard.
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    \2\ 36 FR 8186 (April 30, 1971).
    \3\ 50 FR 37484 (September 13, 1985).
    \4\ 59 FR 38906 (August 1, 1994).
    \5\ 75 FR 54194 (August 31, 2011).
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    Following the enactment of the Clean Air Act (CAA or ``Act'') 
Amendments of 1990, the EPA designated the Las Vegas Valley area as a 
``Moderate'' nonattainment area.\6\ The area was reclassified as a 
``Serious'' nonattainment area on October 2, 1997, when the EPA 
determined the area had not attained the standard after receiving a 
one-year extension of the 1995 attainment date.\7\ Under the CAA, 
states are required to adopt and submit SIPs to attain the NAAQS in 
nonattainment areas within their state.
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    \6\ 56 FR 56694 (November 6, 1991).
    \7\ 62 FR 51604 (October 2, 1997).
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    Under CAA section 175A, one of the criteria for an area to be 
redesignated from nonattainment to attainment is the approval of a 
maintenance plan. The maintenance plan must, among other requirements, 
ensure control measures are in place such that the area will continue 
to maintain the standard for the period extending 10 years after 
redesignation, and include contingency provisions to assure that 
violations of the NAAQS will be promptly remedied.
    In 1994, the EPA set forth new guidelines establishing a 
streamlined process for certain nonattainment areas to meet CAA section 
175A maintenance plan requirements.\8\ This process provides for 
maintenance by demonstrating that future violations of the standard are 
unlikely to occur because the area's design values \9\ are well below 
the NAAQS, and based on the historical stability of the area's air 
quality. A design value is considered well below the NAAQS when it is 
less than or equal to 85 percent of the standard. For CO specifically, 
this would be 85 percent of the 9 ppm 8-hour CO standard, or 7.65 ppm. 
The EPA refers to this streamlined demonstration as a limited 
maintenance plan (LMP). Although the LMP guidelines originally 
addressed the ozone NAAQS, the EPA extended the provisions to apply to 
other pollutants and issued guidance specific for CO nonattainment 
areas.\10\ The LMP must be submitted as a SIP revision and should 
include an attainment emissions inventory, maintenance demonstration, 
provisions for the continued operation of the ambient air quality 
monitoring network for verification of continued attainment, a 
contingency plan in the event of a future violation of the NAAQS, and 
conformity determination provisions.11 12
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    \8\ Memorandum dated November 16, 1994, from Sally L Shaver, 
Director, Air Quality Strategies & Standards Divisions (MD-15) to 
Air Branch Directors, Regions I-X, ``Limited Maintenance Plan Option 
for Nonclassifiable Ozone Nonattainment Areas.''
    \9\ A design value is a statistic that describes the air quality 
status of a certain pollutant for a given location relative to its 
NAAQS.
    \10\ Memorandum dated October 6, 1995, from Joseph W. Paisie, 
Group Leader, Air Quality Management Division (MD-15) to Air Branch 
Chiefs, Regions I-X, ``Limited Maintenance Plan Option for 
Nonclassifiable CO Nonattainment Areas'' (``Paisie Memo'').
    \11\ Id. at 3-5.
    \12\ Memorandum dated September 4, 1992, from John Calcagni, 
Director, Air Quality Management Division (MD-15), Regional Air 
Division Directors, Regions I-X, ``Procedures for Processing 
Requests to Redesignate Areas to Attainment.''
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    In September 2010, the EPA approved the ``Carbon Monoxide 
Redesignation Request and Maintenance Plan, Las Vegas Valley 
Nonattainment Area, Clark County, Nevada (September 2008)'' for the Las 
Vegas Valley area and redesignated the area to attainment.\13\ Under 
CAA section 175A, at the end of the eighth year after the effective 
date of redesignation, the state must submit a second maintenance plan 
to ensure ongoing maintenance of the standard for an additional ten 
years. On June 18, 2019, the State of Nevada submitted the ``Second 10-
Year Carbon Monoxide Limited Maintenance Plan: Las Vegas Valley 
Maintenance Area, Clark County, Nevada (May 2019)'' (``2019 LMP'') for 
the Las Vegas Valley area to fulfill the second maintenance plan 
requirement in CAA section 175A.\14\ The 2019 LMP includes a 
demonstration that the area is expected to remain in attainment of the 
CO NAAQS through the last year of the second 10-year maintenance 
period, that is, through the remainder of the area's full 20-year 
maintenance period.
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    \13\ 75 FR 59090 (September 27, 2010).
    \14\ Letter of submittal dated June 13, 2019, from Greg Lovato, 
Administrator, Nevada Division of Environmental Protection, to 
Elizabeth Adams, Air Division Director, U.S. Environmental 
Protection Agency Region IX (submitted electronically June 18, 
2019).
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II. Nevada's SIP Submittal

    On June 18, 2019, NDEP submitted the 2019 LMP to the EPA as a 
revision to the Nevada SIP. The submittal includes the LMP and 
appendices. Appendices to the plan include air quality data, emissions 
inventory information, air quality monitoring information, and 
documentation of the public review process.

III. The EPA's Evaluation of Nevada's SIP Submittal

A. Procedural Requirements

    Sections 110(a)(2) and 110(l) of the CAA require that a reasonable 
notice and public hearing occur before revisions to a SIP can be 
adopted by the state. Specifically, under 40 CFR part 51, subpart F, 
the EPA requires that

[[Page 41418]]

there must be a publication of a notice by prominent advertisement in 
the relevant geographic area of the proposed SIP revision, a public 
comment period of at least 30 days, and an opportunity for a public 
hearing.
    The Clark County Department of Environment and Sustainability 
(CCDES) \15\ published a notice of a 30-day comment period and notice 
of a public hearing for the 2019 LMP on the Clark County website, and 
the department's website, Twitter, and Facebook pages. An email notice 
was distributed to officials in relevant cities as well as in state and 
local-level departments, districts, authorities, commissions, and 
associations. The CCDES held a public comment period from February 15, 
2019 to March 18, 2019. No formal comments were submitted. On May 7, 
2019, the Clark County Board of County Commissioners held a public 
hearing on the 2019 LMP. No formal comments were submitted during this 
hearing. The CCDES then forwarded the 2019 LMP to the State of Nevada 
and the State submitted the plan to the EPA as a revision to the Nevada 
SIP. The process followed by the CCDES adheres with procedural 
requirements for SIP revisions outlined under CAA section 110 and the 
EPA's implementing regulations.
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    \15\ Formerly Clark County Department of Air Quality.
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B. LMP Requirements

    The EPA reviewed the 2019 LMP that addresses maintenance of the CO 
NAAQS within the Las Vegas Valley area through the end of the 20-year 
period following the area's redesignation, as required under CAA 
section 175A(b).
1. Attainment Emissions Inventory
    For maintenance plans, a state should develop a comprehensive, 
accurate inventory of actual emissions for an attainment year to 
identify the level of emissions sufficient to maintain the NAAQS. For 
CO, the inventory should represent the typical winter day emissions of 
CO for the time period associated with the monitoring data showing 
attainment.\16\ The 2019 LMP includes a CO attainment inventory for the 
Las Vegas Valley area that reflects typical winter weekday emissions in 
2017. Table 1 presents a summary of the inventory for the year 
contained in the maintenance plan. Under an LMP, states are not 
required to project emissions over the maintenance period.
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    \16\ Paisie Memo, 3.

   Table 1--2017 Average Winter Weekday CO Emissions for the Las Vegas
                               Valley Area
                             [Tons per day]
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Point..........................................................     0.93
Nonpoint.......................................................    43.48
Aviation.......................................................    12.53
Onroad Mobile..................................................   217.18
Nonroad Mobile.................................................   114.35
                                                                --------
    Total......................................................   448.96
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    CCDES derived point source emissions using semiannual compliance 
reports submitted to the agency by stationary sources located in the 
Las Vegas Valley area. These reports are required by CCDES' federally-
approved CAA title V operating permits program and include monthly 
reporting data for the facility.\17\ CCDES derived the nonpoint source 
emissions from the EPA's 2016 modeling platform (alpha version) and 
used 2016 as a surrogate for 2017 because the 2017 National Emissions 
Inventory (NEI) for nonpoint sources was not available at the time 
CCDES developed the 2019 LMP. CCDES determined that the differences 
between 2016 and 2017 would be insignificant. Aviation operation data 
for 2014 and 2017 were obtained from the Federal Aviation 
Administration's air traffic activity system and terminal area forecast 
databases and used in conjunction with the 2014 NEI to estimate 
aviation CO emissions for 2017. Onroad and nonroad mobile source data 
were generated using the latest release of the EPA's Motor Vehicle 
Emission Simulator (MOVES) model version MOVES2014b.
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    \17\ CCDES used reporting data for the CO season months January, 
February, and December 2017 to develop emissions for those months 
and convert to daily emissions. See 2019 LMP, 18.
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    Based on our review of the methods, models, and assumptions used by 
CCDES to develop the CO estimates, we find that the 2019 LMP for the 
Las Vegas Valley CO maintenance area includes a comprehensive, accurate 
inventory of CO emissions in the year 2017, and conclude that the 
plan's inventories are acceptable for the purposes of a subsequent 
maintenance plan under CAA section 175A(b).
2. Maintenance Demonstration
    Consistent with prior EPA guidance, if a maintenance area 
demonstrates a maximum 8-hour CO design value of less than or equal to 
85 percent of the CO NAAQS, or 7.65 ppm, for eight consecutive 
quarters, then the EPA considers the area to have met the maintenance 
plan demonstration requirement and that the area will maintain the 
NAAQS for the second 10-year maintenance period.\18\ Such a 
demonstration also assumes continued applicability of prevention of 
significant deterioration (PSD) requirements,\19\ continued 
implementation of any existing control measures in the SIP, and that 
federal measures will remain in place through the end of the second 10-
year maintenance period. The EPA does not require areas using the LMP 
option to project emissions over the maintenance period.
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    \18\ Paisie Memo, 3.
    \19\ PSD applies to new major sources or major modifications at 
existing sources for pollutants where the area of the source's 
location is designated by the EPA as attainment or unclassifiable 
with the NAAQS. Its requirements include, but are not limited to, 
the following: Installation of best available control technology, an 
air quality analysis, an additional impact analysis, and public 
involvement.
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    Table 2 presents the design values for the Las Vegas Valley area 
over the 2012-2020 period. As shown in Table 2, historically, the area 
has consistently been well below 85 percent of the NAAQS. Because the 
CO design values in the Las Vegas Valley area are below the LMP 
threshold over the most recent eight quarters, the EPA finds that the 
State has adequately demonstrated that the area will continue to 
maintain the CO NAAQS over the second 10-year maintenance period and in 
the future.

                                   Table 2--Current and Historical CO Design Values (DV) for the Las Vegas Valley Area
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                                                        Highest second maximum 8-hour CO value  (ppm)
                                              ----------------------------------------------------------------    DV
                     Year                        Jerome Mack     J.D. Smith    Rancho & Teddy   Sunrise Acres   (ppm)       Is DV less than 7.65 ppm?
                                                 (320030540)     (320032002)     (320031501)     (320030540)
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2012.........................................             2.8             2.1  ..............             3.1      3.1  Yes.
2013.........................................             2.8             2.4  ..............             3.1      3.1  Yes.

[[Page 41419]]

 
2014.........................................             2.7             2.4  ..............             2.9      2.9  Yes.
2015.........................................             2.7             2.2  ..............             2.8      2.8  Yes.
2016.........................................             2.3               2  ..............             2.6      2.6  Yes.
2017.........................................            2.35               2         \c\ 1.5             2.8      2.8  Yes.
2018.........................................             2.5         \b\ 1.9             1.5             2.8      2.8  Yes.
2019.........................................             2.3  ..............             1.4             2.8      2.8  Yes.
2020 \a\.....................................             2.1  ..............             1.4             2.4      2.4  Yes.
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Source: EPA, Air Quality System, Design Value Report, March 16, 2021.
\a\ CO design values have no annual completeness requirement.
\b\ The J.D. Smith station was permanently shut down with the EPA's approval on December 31, 2017, due to measurement challenges posed by siting
  obstructions.
\c\ The Rancho & Teddy station opened in 2015 and began monitoring CO in January 2017.

3. Monitoring Network and Verification of Continued Attainment
    The EPA periodically reviews the CO monitoring network operated and 
maintained by CCDES in accordance with 40 CFR part 58. This network is 
consistent with the Clark County ambient air monitoring network plan 
(AMNP) submitted annually to the EPA after a public notification and 
comment process. The EPA has reviewed and approved the AMNP every year 
for the past three years from 2018-2020. The EPA is also required to 
conduct technical systems audits (TSA) every three years to ensure 
quality assurance of monitoring organizations.\20\ The most recent TSA 
for CCDES was in 2018, and the EPA found that CCDES's air monitoring 
program meets EPA's requirements.\21\
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    \20\ 40 CFR 58 Appendix A, section 2.5.
    \21\ Letter dated August 23, 2018 from Elizabeth J. Adams, 
Acting Director, Air Division Region IX, to Marci Henson, Director, 
Clark County Department of Air Quality with attached ``Technical 
Systems Audit of the Ambient Air Monitoring Program: Clark County 
Department of Air Quality October 23-25, 2017 and January 16-18, 
2018.''
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    To verify the attainment status of the area over the maintenance 
period, the maintenance plan should contain provisions for continued 
operations of an EPA-approved monitoring network in accordance with 40 
CFR part 58. The CCDES's network in the Las Vegas Valley area has been 
approved by the EPA in accordance with 40 CFR part 58.\22\ Furthermore, 
the CCDES has committed to continue to operate an air quality 
monitoring network in the Las Vegas Valley area in accordance with the 
EPA requirements to verify continued attainment of the CO NAAQS.\23\ 
For the reasons stated in this section of the notice, we find Clark 
County's monitoring network adequate to verify continued attainment of 
the CO NAAQS in the Las Vegas Valley area.
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    \22\ For further details, see CCDES's 2020 Annual Monitoring 
Network Plan (AMNP), the EPA's approval letter for the 2020, 2019 
and 2018 AMNP, as well as the EPA's Clark County 2018 TSA report, in 
the docket for this action.
    \23\ See 2019 LMP, Section 3.3, ``Monitoring Network/
Verification of Continued Attainment,'' 21.
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4. Contingency Plan
    Section 175A(d) of the CAA requires that a maintenance plan include 
contingency provisions. The purpose of these provisions is to prevent 
future violations of the NAAQS or promptly remediate any NAAQS 
violations that might occur during the maintenance period. These 
contingency provisions need not be fully adopted regulations at the 
time of the redesignation. However, the contingency plan is an 
enforceable part of the SIP and should ensure that contingency measures 
are adopted quickly once the contingency plan is triggered. The 
contingency plan should also identify the measures to be expeditiously 
adopted and provide a schedule and procedure for adoption and 
implementation. The state is also required to identify triggers that 
will be used to determine when contingency measures will need to be 
implemented.
    In the 2019 LMP, the CCDES retains the reduced Reid vapor pressure 
(RVP) gasoline program contingency measure from its first CO 
maintenance plan as a contingency measure. The RVP gasoline program 
relaxed the RVP from wintertime fuels sold in Clark County from 9.0 
pounds per square inch (psi) to 13.5 psi, thereby increasing fuel 
volatility and therefore fuel-related emissions. The EPA approved this 
measure, finding that relaxation of RVP would not interfere with 
maintenance of the CO standard in the area.\24\ The RVP gasoline 
program contingency measure would reinstate the prior, lower RVP level. 
That is, if future CO levels trigger contingency measures, the CCDES 
will seek reinstatement and tightening of the RVP standard back to 9.0 
psi. This contingency measure would be triggered by a verified second 
exceedance over 9 ppm during the winter season (October 1 through March 
31) within a consecutive two-year period.
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    \24\ 75 FR 59090.
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    The EPA proposes to find that the contingency provisions in the 
2019 LMP satisfy the contingency measure requirements of CAA section 
175A for the second 10-year maintenance plan period.

IV. Transportation Conformity

    Transportation conformity is required by section 176(c) of the CAA. 
Conformity to a SIP means that transportation activities will not 
produce new air quality violations, worsen existing violations, or 
delay timely attainment of the NAAQS. The EPA's conformity rule at 40 
CFR part 93 requires that transportation plans, programs, and projects 
conform to SIPs and establishes the criteria and procedures for 
determining conformity. The conformity rule generally requires a 
demonstration that emissions from the regional transportation plan 
(RTP) and the transportation improvement plan (TIP) are consistent with 
the motor vehicle emissions budget (MVEB or ``budget'') contained in 
the control strategy SIP revision or maintenance plan.\25\ A budget is 
defined as the level of mobile source emissions of a pollutant relied 
upon in the attainment or maintenance demonstration to attain or 
maintain compliance with the

[[Page 41420]]

NAAQS in the nonattainment or maintenance area.\26\
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    \25\ See 40 CFR 93.101, 93.118, and 93.124.
    \26\ Further information concerning the EPA's interpretations 
regarding MVEBs can be found in the preamble to the EPA's November 
24, 1993, transportation conformity rule. See 58 FR 62193-62196, 
November 24, 1993.
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    Under the conformity rule, areas submitting an LMP for the second 
10-year maintenance plan may demonstrate conformity without a regional 
emissions analysis as outlined in 40 CFR 93.109(e). When the EPA 
approves an LMP, the EPA is concluding that a budget may be treated as 
essentially not constraining for the length of the maintenance period. 
Areas that qualify for an LMP may demonstrate conformity without a 
regional emissions analysis because it is unreasonable to expect that 
such an area will experience so much growth in the 10-year period of 
the LMP that a violation of the CO NAAQS would result.\27\ All actions 
that would require transportation conformity determinations for the Las 
Vegas Valley area under the transportation conformity rule provisions 
would be considered to have already satisfied the regional emissions 
analysis and ``budget test'' requirements in 40 CFR 93.118 as a result 
of our final approval of the 2019 LMP.
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    \27\ Paisie Memo, 3-4.
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    However, because LMP areas are still maintenance areas, approval of 
the 2019 LMP would not relieve transportation agencies of certain 
determinations still required for transportation plans, programs, and 
projects. Specifically, RTPs, TIPs and transportation projects must 
still demonstrate that they are fiscally constrained,\28\ meet the 
criteria for consultation,\29\ and provide for timely implementation of 
transportation control measures from the applicable implementation 
plan.\30\ Conformity determinations for RTPs and TIPs must also be 
determined no less frequently than every four years, and conformity of 
plan and TIP amendments and transportation projects demonstrated in 
accordance with the timing requirements specified in 40 CFR 93.104. For 
projects to be approved they must be listed in a currently conforming 
RTP and TIP.\31\ In addition, projects in LMP areas are required to 
meet the applicable criteria for CO hot spot analyses to satisfy 
``project level'' conformity determinations,\32\ which must also 
incorporate the latest planning assumptions and models available.\33\
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    \28\ 40 CFR 93.108.
    \29\ 40 CFR 93.105 and 40 CFR 93.112.
    \30\ 40 CFR 93.113.
    \31\ 40 CFR 93.114 and 93.115.
    \32\ 40 CFR 93.116 and 40 CFR 93.123.
    \33\ 40 CFR 93.110 and 40 CFR 93.111, respectively. See 40 CFR 
93.109(b), Table 1.
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    If the area should monitor CO concentrations at or above the 
limited maintenance eligibility criteria, or 7.65 ppm, then that 
maintenance area would no longer qualify for a LMP and would revert to 
a full maintenance plan. In this event, the LMP would remain applicable 
for conformity purposes only until the full maintenance plan is 
submitted and the EPA has either found its motor vehicle emissions 
budget adequate for conformity purposes or approves the full 
maintenance plan SIP revision. At that time regional emissions analyses 
would resume as a transportation conformity criterion.
    The EPA posted Las Vegas Valley's 2019 LMP for CO on its adequacy 
review website on June 23, 2021.\34\ The EPA will accept comments from 
the public for up to 30 days after the LMP has been posted on the 
website. The EPA will consider the comments and then may elect to 
proceed with finding the 2019 LMP adequate for transportation 
conformity purposes either as part of the SIP's final approval or in a 
separate notice of adequacy. The EPA's adequacy review process is 
described in 40 CFR part 93.118(f).
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    \34\ https://www.epa.gov/state-and-local-transportation/adequacy-review-state-implementation-plan-sip-submissions-conformity.
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    If finalized, our approval of the 2019 LMP would effectively affirm 
our adequacy finding such that no regional emissions analysis for 
future transportation CO conformity determinations are required for the 
2019 LMP period and beyond. The other transportation conformity 
requirements listed above would continue to apply.
    In addition to transportation conformity, approval of the 2019 LMP 
would have implications for general conformity.\35\ Federal actions 
subject to general conformity would be presumed to conform under a 
limited maintenance plan as actions in this area will automatically 
satisfy the budget test of 40 CFR 93.158(a)(5)(i)(A), as described in 
in an EPA memorandum entitled ``Limited Maintenance Plan Option for 
Nonclassifiable CO Nonattainment Areas'' on limited maintenance plans 
for CO nonattainment areas.\36\
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    \35\ 40 CFR part 93 Subpart B.
    \36\ Paisie Memo, 4-5.
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V. Proposed Action and Public Comment

    Under section 110(k)(3) of the CAA, the EPA is proposing to approve 
the 2019 LMP as a revision to the Nevada SIP because we find that it 
satisfies the requirements of section 175A of the CAA.
    The 2019 LMP adequately demonstrates maintenance of the CONAAQS 
well below the standard through documentation of monitoring data 
showing the historical CO design values of the area. It also satisfies 
the other core provisions of an LMP: It has an accurate and 
comprehensive emissions inventory representing attainment, a 
contingency plan, and a commitment to continue operation of an 
acceptable ambient monitoring network to verify continued attainment 
over the second 10-year period. We find the 2019 LMP to be sufficient 
to provide for maintenance of the CO NAAQS in the Las Vegas Valley area 
over the second 10-year maintenance period (through 2030) and thereby 
satisfy the requirements for such a plan under CAA section 175A(b).
    The EPA is soliciting public comments on the issues discussed in 
this notice. We will accept comments from the public on this proposal 
for the next 30 days and will consider these comments before taking 
final action.

VI. Statutory and Executive Order Reviews

    Under the Clean Air Act, the Administrator is required to approve a 
SIP submission that complies with the provisions of the Act and 
applicable federal regulations. 42 U.S.C. 7410(k); 40 CFR 52.02(a). 
Thus, in reviewing SIP submissions, the EPA's role is to approve state 
choices, provided that they meet the criteria of the Clean Air Act. 
Accordingly, this proposed action merely proposes to approve state law 
as meeting federal requirements and does not impose additional 
requirements beyond those imposed by state law. For that reason, this 
proposed action:
     Is not a ``significant regulatory action'' subject to 
review by the Office of Management and Budget under Executive Orders 
12866 (58 FR 51735, October 4, 1993) and 13563 (76 FR 3821, January 21, 
2011);
     Does not impose an information collection burden under the 
provisions of the Paperwork Reduction Act (44 U.S.C. 3501 et seq.);
     Is certified as not having a significant economic impact 
on a substantial number of small entities under the Regulatory 
Flexibility Act (5 U.S.C. 601 et seq.);
     Does not contain any unfunded mandate or significantly or 
uniquely affect small governments, as described in the Unfunded 
Mandates Reform Act of 1995 (Pub. L. 104-4);
     Does not have federalism implications as specified in 
Executive

[[Page 41421]]

Order 13132 (64 FR 43255, August 10, 1999);
     Is not an economically significant regulatory action based 
on health or safety risks subject to Executive Order 13045 (62 FR 
19885, April 23, 1997);
     Is not a significant regulatory action subject to 
Executive Order 13211 (66 FR 28355, May 22, 2001);
     Is not subject to requirements of section 12(d) of the 
National Technology Transfer and Advancement Act of 1995 (15 U.S.C. 272 
note) because application of those requirements would be inconsistent 
with the Clean Air Act; and
     Does not provide the 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, the 2019 LMP is not proposed to apply on any Indian 
reservation land or in any other area where the EPA or an Indian tribe 
has demonstrated that a tribe has jurisdiction. The Las Vegas Tribe of 
Paiute Indians has areas of Indian country located in the Las Vegas 
Valley CO maintenance area. In those areas of Indian country, the 2019 
LMP does not apply, and therefore, this proposed action does not have 
tribal implications and would not, if approved, impose substantial 
direct costs on tribal governments or preempt tribal law as specified 
by Executive Order 13175 (65 FR 67249, November 9, 2000).

List of Subjects in 40 CFR Part 52

    Environmental protection, Air pollution control, Incorporation by 
reference, Intergovernmental relations, Carbon Monoxide, Pollution.

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

    Dated: July 22, 2021.
Deborah Jordan,
Acting Regional Administrator, Region IX.
[FR Doc. 2021-16453 Filed 7-30-21; 8:45 am]
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