[Federal Register Volume 87, Number 113 (Monday, June 13, 2022)]
[Proposed Rules]
[Pages 35705-35709]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2022-12609]


-----------------------------------------------------------------------

ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 52

[EPA-R09-OAR-2022-0131; FRL-9739-01-R9]


Clean Air Plans; Base Year Emissions Inventories for the 2015 
Ozone Standards; Nevada; Clark County, Las Vegas Valley

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.

-----------------------------------------------------------------------

SUMMARY: The Environmental Protection Agency (EPA) is proposing to 
approve, under the Clean Air Act (CAA or ``Act''), revisions to the 
Nevada State Implementation Plan (SIP) concerning the base year 
emissions inventory requirements for the Las Vegas Valley ozone 
nonattainment area located within Clark County for the 2015 ozone 
national ambient air quality standards (NAAQS or ``standards'').

DATES: Any comments must arrive by July 13, 2022.

ADDRESSES: Submit your comments, identified by Docket ID No. EPA-R09-
OAR-2022-0131 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 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: Lindsay Wickersham, Air Planning 
Office (AIR-2), EPA Region IX, (415) 947-4192, 
[email protected].

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

Table of Contents

I. Background
    A. Emissions Inventories
    B. State Submittals
    C. Public Notice and Hearing Requirements
II. Clark County's Emissions Inventory
    A. Base Year Emissions Inventory for the Las Vegas Valley 
Nonattainment Area
III. EPA's Evaluation
IV. Proposed Action and Request for Public Comment
V. Statutory and Executive Order Reviews

I. Background

    On October 26, 2015, the EPA promulgated a revised 8-hour ozone 
NAAQS of 0.070 parts per million.\1\ In accordance with section 107(d) 
of the CAA, the EPA must designate an area ``nonattainment'' if it is 
violating the NAAQS or if it is contributing to a violation of the 
NAAQS in a nearby area. In February 2018, Clark County submitted a 
recommendation based on 2015-2017 monitoring data, requesting that the 
Las Vegas Valley be designated nonattainment for the 2015 ozone 
NAAQS.\2\ The EPA approved the request and designated the Las Vegas 
Valley in Clark County as a ``Marginal'' ozone nonattainment zone for 
the 2015 ozone NAAQS effective August 3, 2018.\3\
---------------------------------------------------------------------------

    \1\ 80 FR 65292.
    \2\ Letter dated February 23, 2018, from Greg Lovato, 
Administrator, Nevada Division of Environmental Protection, to 
Alexis Strauss, Acting Regional Administrator, EPA Region IX.
    \3\ 83 FR 25776, 25819.
---------------------------------------------------------------------------

A. Emissions Inventories

    Sections 172(c)(3) and 182(a)(1) of the CAA require states to 
develop and submit, as a SIP revision, ``base year'' emissions 
inventories for all areas designated as nonattainment for an ozone 
NAAQS. The EPA finalized the 2015 ozone NAAQS SIP Requirements Rule 
(SRR) on December 6, 2018.\4\ The SRR established implementation 
requirements for the 2015 ozone NAAQS, including requirements for base 
year emissions inventories under CAA section 182(a)(1). The SRR for the 
2015 ozone NAAQS is codified at 40 CFR part 51, subpart CC, and the 
emissions inventory requirements are codified at 40 CFR 51.1315.
---------------------------------------------------------------------------

    \4\ 83 FR 62998.
---------------------------------------------------------------------------

    An emissions inventory for ozone is an estimation of actual 
emissions of air pollutants that contribute to the formation of ozone 
in an area. Ozone is a gas that is formed by the reaction of volatile 
organic compounds (VOC) and oxides of nitrogen (NOX), 
referred to as ozone precursors, in the atmosphere in the presence of 
sunlight. Therefore, an emissions inventory for ozone focuses on the 
emissions of VOC and NOX. VOC is emitted by many types of 
sources, including power plants, industrial sources, on-road and off-
road mobile sources, smaller stationary sources collectively referred 
to as area sources, and biogenic sources. NOX is primarily 
emitted by combustion sources, both stationary and mobile.
    Emissions inventories provide emissions data that inform a variety 
of air quality planning tasks, including the following: establishing 
baseline emissions levels, calculating emissions reduction targets 
needed to attain the NAAQS and to achieve reasonable further progress 
(RFP) toward attainment of an ozone standard,\5\ determining emissions 
inputs for ozone air quality modeling analyses, and tracking emissions 
over time to determine progress toward achieving air quality and 
emissions reduction goals.
---------------------------------------------------------------------------

    \5\ The RFP requirements specified in CAA section 182(b)(1) 
apply to all areas classified as ``Moderate'' or higher ozone 
nonattainment. At the time of submittal of the Clark County base 
year emissions inventory SIPs for the 2015 ozone NAAQS, the Clark 
County area was designated Marginal nonattainment for the 2015 ozone 
NAAQS and were therefore not required to demonstrate RFP toward 
attainment of the 2015 ozone NAAQS.
---------------------------------------------------------------------------

    For the 2015 ozone NAAQS, states are required to submit ozone 
season day emissions estimates for an inventory calendar year to be 
consistent with the

[[Page 35706]]

baseline year for RFP plans as required by 40 CFR 51.1310(b).\6\ Under 
40 CFR 51.1310(b), for the 2015 ozone NAAQS, the RFP baseline year is 
the most recent calendar year for which a complete triennial inventory 
is required to be submitted to the EPA under 40 CFR 51 subpart A.\7\ 
States may use an alternative base year emissions inventory provided 
that the year selected corresponds with the year of the effective date 
of designation as nonattainment for that NAAQS. Ozone season day 
emissions are defined in 40 CFR 51.1300(q) as ``the average day's 
emissions for a typical ozone season work weekday.'' Under the 
definition in 40 CFR 51.1300(q), states are required to select the 
months in the ozone season and the days in the work week to be 
represented. Based on the EPA's 2017 guidance on emissions inventory 
development, the selected ozone season should be representative of the 
conditions leading to nonattainment.\8\
---------------------------------------------------------------------------

    \6\ 40 CFR 51.1315(a).
    \7\ 83 FR 62998, 63034.
    \8\ EPA, ``Emissions Inventory Guidance for Implementation of 
Ozone and Particulate Matter National Ambient Air Quality Standards 
(NAAQS) and Regional Haze Regulations'' (May 2017), 75.
---------------------------------------------------------------------------

B. State Submittals

    On October 15, 2020, the Nevada Department of Environmental 
Protection (NDEP) submitted a revision to the Nevada SIP titled, 
``Revision to the Nevada State Implementation Plan for the 2015 Ozone 
NAAQS: Emissions Inventory and Emissions Statement Requirements'' 
(``2020 Clark County EI'').\9\ The 2020 Clark County EI includes a 2017 
base year emissions inventory for the Las Vegas Valley nonattainment 
area, developed by the Clark County Department of Environment and 
Sustainability (CCDES), and supporting documentation regarding the 
development of the base year emissions inventory.
---------------------------------------------------------------------------

    \9\ Letter dated October 8, 2020, from Greg Lovato, 
Administrator, Nevada Division of Environmental Protection, to 
Elizabeth Adams, Director, Air Division, EPA Region IX. Transmitted 
via US EPA's State Planning Electronic Collaboration System (SPeCS) 
on October 15, 2020.
---------------------------------------------------------------------------

    CCDES provided supplementary information (SI) to the 2020 Clark 
County EI addressing comments and questions raised by the EPA following 
receipt of CCDES's prior submittal on February 10, 2022, February 14, 
2022, and on March 30, 2022.\10\ Together these three supplementary 
exchanges are known as the ``2020 Clark County SI.''
---------------------------------------------------------------------------

    \10\ Email dated February 10, 2022, from Zheng Li, CCDES, to 
Lindsay Wickersham, EPA Region IX, Subject: ``RE: Introduction and 
Qs on 2015 O3 EI.''; Email dated February 14, 2022, from Araceli 
Pruett, CCDES to Lindsay Wickersham, EPA Region IX, Subject: ``RE: 
Introduction and Qs on 2015 O3 EI.,'' with attachment, ``20220203 
EPA Request for Add'l Info on 2015 O3 EI.docx.''; Email Dated March 
30, 2022, from Araceli Pruett, CCDES to Lindsay Wickersham, EPA 
Region IX, Subject: ``RE: A few questions: ERCs, QA, etc.,'' with 
attachment, ``20220329 EPA Request for Add'l Info on 2015 O3 
EI.docx.''
---------------------------------------------------------------------------

    In this action, we are evaluating and proposing action on the 2020 
Clark County EI and the 2020 Clark County SI that we will collectively 
refer to as the ``2020 Clark County SIP Submittal.''

C. Public Notice and Hearing Requirements

    Sections 110(a)(1) and 110(l) of the CAA and 40 CFR 51.102 require 
states to provide reasonable notice and an opportunity for a public 
hearing prior to adoption of SIP revisions. Section 110(k)(1)(B) 
requires the EPA to determine whether a SIP submittal is complete 
within 60 days of receipt. Any plan that the EPA does not affirmatively 
determine to be complete or incomplete will become complete by 
operation of law six months after the date of submittal. A finding of 
completeness does not approve the submittal as part of the SIP, nor 
does it indicate that the submittal is approvable. It does start a 12-
month clock for the EPA to act on the SIP submittal (see CAA section 
110(k)(2)).
    The 2020 Clark County SIP Submittal includes documentation of the 
public review process CCDES followed prior to its submittal to the EPA 
as revisions to the SIP. Appendix B of the 2020 Clark County EI 
includes documentation of notices of opportunity for public hearing and 
comment on the SIP submittal. CCDES posted these notices on CCDES 
Facebook and Twitter pages, sent them by email to interested parties, 
and posted them on CCDES and Clark County websites. Included in 
Appendix B of the 2020 Clark County EI are agendas and meeting 
summaries from two Board of Commissioners meetings, setting and 
conducting the public hearing. Public comment reports included in 
Appendix B indicate that CCDES received no comments during the 30-day 
public review period.

II. Clark County's Emissions Inventory

    The 2020 Clark County SIP Submittal addresses the emissions 
inventory requirement in CAA section 182(a)(1). The submittal provides 
documentation of a 2017 base year inventory of emissions of 
NOX and VOCs. The 2017 base year emissions inventory was the 
most recent triennial emissions inventory in the National Emissions 
Inventory (NEI) at the time the emissions inventories were prepared for 
the Clark County area.
    The emissions inventory submittal includes emissions estimates for 
the following source categories: point sources, nonpoint sources, 
onroad mobile sources, nonroad mobile sources, commercial and federal 
aviation, and biogenic sources. Point sources are large, stationary 
(i.e., non-mobile) sources of emissions that release pollutants. 
Nonpoint sources, also referred to as ``area'' sources, are the sources 
of air pollutants that fall below point source reporting levels or are 
too small or too numerous to be identified individually, such as small-
scale industrial or residential operations that use emission-generating 
materials or processes. Nonroad mobile sources are not certified for 
highway use and include equipment that can either move under their own 
power or can be moved from site to site.\11\ Onroad mobile sources are 
motor vehicles traveling on local highways and roads. Biogenic sources 
emit pollutants produced by natural sources including vegetation and 
soils. Commercial and federal aviation consists of emissions from 
aircraft and airport ground support equipment for commercially run 
facilities and federally owned facilities respectively.
---------------------------------------------------------------------------

    \11\ Locomotive emissions are included in the nonpoint category. 
Aircraft and airport ground support equipment are included in the 
aviation categories.
---------------------------------------------------------------------------

    CCDES employed a combination of top-down estimation techniques 
(i.e., allocation of regional emissions estimates to a smaller, defined 
geographic area) and bottom-up estimation techniques (i.e., development 
of source or source category emissions estimates using emissions 
factors, models, etc.) to develop the emissions inventories in their 
SIP submittal.

A. Base Year Emissions Inventory for the Las Vegas Valley Nonattainment 
Area

    The emissions inventory included in the 2020 Clark County SIP 
Submittal was developed by CCDES. The Clark County ozone nonattainment 
area for the 2015 NAAQS consists of Hydrographic Area 212, also 
referred to by CCDES as the Las Vegas Valley.\12\ CCDES selected the 
month of July to estimate ozone season day emissions of NOX 
and VOC from sources in the Las Vegas Valley.\13\
---------------------------------------------------------------------------

    \12\ See 83 FR 25776, 25819 (June 4, 2018) (providing a 
description of the boundaries of the Clark County nonattainment area 
for the 2015 ozone NAAQS); see also Figure 1-1 in 2020 Clark County 
EI for a map of the nonattainment area.
    \13\ In Clark County, the highest ambient ozone concentrations 
generally occur during the months of the year when the highest 
temperatures occur--typically from May through September. For SIP 
planning purposes, CCDES selected weekdays in the month of July as 
the basis to estimate typical summertime weekday emissions, as is 
precedent for Clark County SIPs. See 86 FR 43461, 43464 (August 9, 
2021).

---------------------------------------------------------------------------

[[Page 35707]]

    In the 2020 Clark County SIP Submittal, the point source inventory 
includes all Title V stationary sources and all sources with the 
potential to emit at least 10 tons of VOCs or 25 tons of NOX 
in 2017. All sources emitting less than these thresholds were included 
in the nonpoint source category. CCDES identified 110 stationary point 
sources meeting this point source definition in the Las Vegas 
Valley.\14\
---------------------------------------------------------------------------

    \14\ All point sources identified in the Las Vegas Valley are 
permitted by the CCDES Division of Air Quality and required to 
submit annual emissions reports under Section 12.9 of the Clark 
County Air Quality Regulations (AQR). These annual emission reports 
were used to identify individual stationary point sources within the 
Las Vegas Valley for this emissions inventory.
---------------------------------------------------------------------------

    CCDES calculates actual emissions from point sources using data 
collected from annual source emissions reports, permit files and 
associated technical support documents (TSD), direct on-site 
measurements (e.g., continuous emission monitors (CEMS)), or calculated 
using EPA emission factors (e.g., AP-42) and activities data.\15\
---------------------------------------------------------------------------

    \15\ On-site measurements are collected from emission units that 
are required to have CEMS, as outlined in Section 12.10 of the Clark 
County AQR. All other point sources emissions were calculated based 
on emissions factors in the permit and activity data.
---------------------------------------------------------------------------

    Nonpoint source emissions within the Las Vegas Valley were 
estimated using the 2017 NEI emissions estimates for Clark County. To 
generate the sub-county emissions from the Las Vegas Valley, the Sparse 
Matrix Operator Kernel Emissions (SMOKE) model was run with a 4-km grid 
spacing over the nonattainment area for July to generate ozone season 
weekday emissions estimates using annual nonpoint emissions data.\16\ 
Ancillary files developed by the EPA for version 1 of the 2016 modeling 
platform were used when running SMOKE.\17\ The nonpoint inventory 
includes different emissions sectors: locomotive, residential wood 
combustion, agriculture livestock, and other nonpoint sources.\18\
---------------------------------------------------------------------------

    \16\ For a map of the modeled area, see 2020 Clark County EI, 
Figure 1-1, A-4; Characterized by Source Classification Code (SCC) 
in the FF10 Flat data file; EPA, ``Technical Support Document (TSD) 
Preparation of Emissions Inventories for the 2016v1 North American 
Emissions Modeling Platform'' (March 2021), 123.
    \17\ Files and technical support documents available at https://www.epa.gov/air-emissions-modeling/2016v1-platform.
    \18\ See 2020 Clark County SI Section C for detailed emissions 
from each emission sector.
---------------------------------------------------------------------------

    Nonroad mobile sources in the Las Vegas Valley emissions inventory 
encompass a wide variety of equipment types that are not certified for 
highway use and can either move under their own power or can be moved 
from site to site.\19\ CCDES estimated nonroad emissions within the Las 
Vegas Valley using the 2017 NEI emissions estimates for Clark County 
that were generated using the nonroad module of the EPA's Motor Vehicle 
Emission Simulator (version MOVES2014b), which was the latest model 
available at the time the inventory was developed.\20\ To generate the 
sub-county emissions from the Las Vegas Valley, the SMOKE model was run 
with a 4-km grid spacing over the nonattainment area for July to 
generate ozone season weekday emissions estimates using monthly nonroad 
emissions data.\21\ Ancillary data files used when running SMOKE were 
developed by the EPA for version 1 of the 2016 modeling platform and 
had a base year of 2016 for use in photochemical modeling.\22\
---------------------------------------------------------------------------

    \19\ Locomotive, aircraft, and airport ground support equipment 
are not included in this category.
    \20\ EPA, ``Policy Guidance on the Use of MOVES3 for State 
Implementation Plan Development, Transportation Conformity, General 
Conformity, and Other Purposes'' (November 2020), 7.
    \21\ Characterized by Source Classification Code (SCC) in the 
FF10 Flat data file; EPA, ``Technical Support Document (TSD) 
Preparation of Emissions Inventories for the 2016v1 North American 
Emissions Modeling Platform'' (March 2021), 123.
    \22\ Files and technical support documents available at https://www.epa.gov/air-emissions-modeling/2016v1-platform.
---------------------------------------------------------------------------

    Onroad mobile sources in the Las Vegas Valley emissions inventory 
consist of cars, trucks, buses, motorcycles, and other motor vehicles 
that travel on local and highway roads. CCDES developed a Clark County-
specific MOVES input database for 2017 using the latest available 
information. Key inputs for MOVES included in this database were annual 
vehicle miles traveled (VMT), vehicle population by source type, fleet 
age distributions, fuel parameters, inspection and maintenance 
programs, hoteling activity, and ambient temperature and humidity data. 
Sources for these inputs include the 2018 Clark County vehicle 
classification study, the Nevada Department of Motor Vehicle 
registration database, the Nevada Department of Transportation's (NDOT) 
annual Highway Performance Monitoring System reports, data from the 
Regional Transportation Council, the online magazine Schoolbusfleet, 
meteorological data collected at McCarran International Airport, the 
Coordinated Research Council's vehicle identification number decoding 
project and default model input files.
    To generate sub-county data from this database, CCDES assumed the 
population within the Las Vegas Valley to be 95 percent of the total 
population of Clark County \23\ and used Las Vegas Valley specific 
annual VMT data for each vehicle source type as provided by NDOT. CCDES 
estimated emissions from onroad mobile sources using MOVES2014b in 
inventory mode to generate sub-county data for the Las Vegas Valley.
---------------------------------------------------------------------------

    \23\ The EPA has previously accepted this assumption for other 
plans submitted regarding Las Vegas (see e.g., 79 FR 60078). The 
human population of the Las Vegas Valley is around 96.7 percent. 
Sensitivity analysis showed that the values in MOVES was not 
sensitive to a 1.67 percent change.
---------------------------------------------------------------------------

    Biogenic sources included in this inventory include crops, lawn 
grass, vegetation, soil, and forests. Emissions from biogenic sources 
in the Las Vegas Valley area were calculated using the Biogenic 
Emissions Inventory System Version 3.61 (BEIS 3.61) embedded in SMOKE 
4.7. BEIS requires inputs of meteorological and landcover data. CCDES 
utilized 12-kilometer data collected from the 2016 version 1 Weather 
Research and Forecasting model, and the newly released Biogenic 
Emissions Landcover Database version 5 (BELD5).\24\
---------------------------------------------------------------------------

    \24\ BELD5 includes version 8.0 of the Forest Inventory and 
Analysis, which has better agreement with measured foliage biomass 
to improve VOC emissions estimates.
---------------------------------------------------------------------------

    Emissions from commercial aviation within the Las Vegas Valley 
encompasses three facilities: McCarran International Airport, North Las 
Vegas Airport, and Henderson Executive Airport. Emissions inventories 
were developed using the Federal Aviation Administration's Aviation 
Environmental Design Tool (AEDT) Version 3b. The Clark County 
Department of Aviation used default meteorology in AEDT with correction 
factors to account for differences in meteorology and activity data 
between the model's default design day of October and a typical July 
weekday. The 2020 Clark County SI shows corrected tons per day (tpd) 
values adjusted with correction factors for all three airports compared 
to the values provided in the 2020 Clark County EI. These corrected 
values are included in Table 2 below.
    Emissions from federally controlled aviation sources within Las 
Vegas Valley consist entirely of emissions from Nellis Air Force Base. 
Actual emissions from aircraft operations were obtained from EPA's 2017 
NEI Data.
    CCDES employed quality assurance and quality control (QA/QC) 
measures

[[Page 35708]]

throughout the development of the 2020 Clark County emissions 
inventory. Point source emissions calculations were checked by CCDES 
compliance staff against the permitting Technical Support Document 
(TSD).\25\ These reviewed and corrected emissions data are used in the 
emissions inventories. Nonroad and nonpoint emissions outcomes were 
compared to those from the NEI and other counties for reasonableness 
and consistency and were checked for spatial distributions with gridded 
emissions maps.\26\ Onroad emissions had a variety of input sources and 
thus implemented multiple types of QA/QC practices outlined in the 2020 
Clark County SI. Emissions data collected for the 2017 NEI was subject 
to QA/QC from the EPA and was compared by CCDES to other counties in 
Nevada and to other years for consistency and reasonableness.\27\ 
CCDES's QA/QC measures are described in further detail in the 2020 
Clark County SI.
---------------------------------------------------------------------------

    \25\ CCDES, ``Emissions Inventory Report Review and Audit 
Process'' (March 2021).
    \26\ Gridded emissions map shown in 2020 Clark County SI, 
Section (b)(iii) and Section (c)(iii).
    \27\ EPA, ``2017 National Emissions Inventory Summary of Quality 
Assurance Information'' (January 2022).
---------------------------------------------------------------------------

    Estimates of 2017 ozone season day emissions of NOX and 
VOC in the Las Vegas Valley are summarized in Table 2 below.

    Table 2--2017 Ozone Season Day Emissions for the Las Vegas Valley
                           Nonattainment Area
------------------------------------------------------------------------
                                                     Pollutant
             Source category             -------------------------------
                                            NOX  (tpd)      VOC  (tpd)
------------------------------------------------------------------------
Point...................................            2.94            1.25
Nonpoint................................            6.94           59.49
Commercial Aviation.....................       \a\ 11.40            1.70
Federal Aviation........................            0.50            0.24
On-road Mobile..........................           38.76           27.25
Nonroad Mobile..........................           36.58           23.96
Biogenic................................            0.86          124.19
                                         -------------------------------
    Area Total..........................           97.98          238.07
------------------------------------------------------------------------
Sources: 2020 Clark County EI section 9, 2020 Clark County SI.
Note:
\a\ Corrected value provided from 2020 Clark County SI, Section e.

III. EPA's Evaluation

    Based on the documentation included in Clark County's submittals, 
the EPA finds that the submittals satisfy the procedural requirements 
of sections 110(a)(1) and 110(l) of the Act requiring states to provide 
reasonable notice and an opportunity for public hearing prior to 
adoption of SIP revisions. The 2020 Clark County SIP Submittal became 
complete by operation of law on April 15, 2021, pursuant to CAA section 
110(k)(1)(B).
    The EPA has reviewed Clark County's submittals for consistency with 
CAA sections 172(c)(3) and 182(a)(1) and the requirements for emissions 
inventories under the EPA's implementing regulations for the 2015 ozone 
NAAQS at 40 CFR 51.1315. The 2017 base year emissions inventories 
represent the most recent calendar year for which a consistent and 
comprehensive statewide inventory was available. The selection of 2017 
as the base year for the Las Vegas Valley emissions inventory is 
therefore consistent with the requirement for selection of RFP baseline 
years under 40 CFR 51.1310(b). We find that for the Las Vegas Valley 
emissions inventory Clark County appropriately estimated the average 
day's emissions for a typical weekday in the ozone season, consistent 
with the definition of ozone season day emissions under 40 CFR 
51.1300(q).
    Clark County's submittals document the procedures used by CCDES to 
estimate ozone season day emissions for each of the major source types. 
Documentation of emissions estimation procedures in the 2020 Clark 
County SIP Submittal demonstrate that CCDES followed acceptable 
procedures to develop emissions estimates. The 2020 Clark County SIP 
Submittal also describes the specific QA/QC measures implemented to 
ensure the accuracy and integrity of data throughout the development of 
the emissions inventory.
    Based upon the documentation of emissions estimation techniques and 
QA/QC procedures employed to develop the emissions inventories in the 
submittal, we find that the 2020 Clark County SIP Submittal contains 
comprehensive, accurate, current inventories of actual emissions from 
all sources in the Las Vegas Valley nonattainment area. The EPA 
therefore proposes to approve the base year inventories of 
NOX and VOC emissions for the Las Vegas Valley ozone 
nonattainment area for the 2015 ozone NAAQS submitted by Nevada 
pursuant to 40 CFR 51.1315 and CAA sections 172(c)(3) and 182(b)(1).

IV. Proposed Action and Request for Public Comment

    We are proposing to approve the 2020 Clark County SIP Submittal as 
meeting the ozone-related base year emissions inventory requirement for 
the Las Vegas Valley nonattainment area for the 2015 ozone NAAQS. The 
emissions inventory we are proposing to approve into the SIP is 
summarized in Table 2. We are proposing to approve this emissions 
inventory because it contains comprehensive, accurate, and current 
inventories of actual emissions for all relevant sources in accordance 
with CAA sections 172(c)(3) and 182(a)(1). The EPA is soliciting public 
comments on the issues discussed in this proposed rule. We will accept 
comments from the public on this proposal for the next 30 days.

V. Statutory and Executive Order Reviews

    Under the Clean Air Act, the Administrator is required to approve a 
SIP submission that complies with the provisions of the Act and 
applicable federal regulations. 42 U.S.C. 7410(k); 40 CFR 52.02(a). 
Thus, in reviewing SIP submissions, 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 
plans

[[Page 35709]]

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 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 SIP is not approved 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 of the Las Vegas Indian Colony have areas of Indian 
country located within the Las Vegas Valley nonattainment area for the 
2015 ozone NAAQS. In those areas of Indian country, the proposed rule 
does not have tribal implications and will not 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, Ozone, Reporting and 
recordkeeping requirements, Volatile organic compounds.

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

    Dated: June 6, 2022.
Martha Guzman Aceves,
Regional Administrator, Region IX.
[FR Doc. 2022-12609 Filed 6-10-22; 8:45 am]
BILLING CODE 6560-50-P