[Federal Register Volume 90, Number 65 (Monday, April 7, 2025)]
[Proposed Rules]
[Pages 14935-14939]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2025-05910]
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ENVIRONMENTAL PROTECTION AGENCY
40 CFR Part 52
[EPA-R01-OAR-2025-0076; FRL-12691-01-R1]
Air Plan Approval; Connecticut; 2017 Base Year Emissions
Inventory for the 2015 8-Hour Ozone National Ambient Air Quality
Standards
AGENCY: Environmental Protection Agency (EPA).
ACTION: Proposed rule.
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SUMMARY: The Environmental Protection Agency (EPA) is proposing
approval of State Implementation Plan (SIP) revisions submitted by the
State of Connecticut that relate to the 2015 Ozone National Ambient Air
Quality Standards (NAAQS). The SIP revisions are for the Greater
Connecticut and the Connecticut portion of the New York-Northern New
Jersey-Long Island, NY-NJ-CT ozone nonattainment areas. The intended
effect of this action is to propose approval of submittals which
include a 2017 base year emissions inventory for the 2015 Ozone
National Ambient Air Quality Standard. This action is being taken under
the Clean Air Act.
DATES: Written comments must be received on or before May 7, 2025.
ADDRESSES: Submit your comments, identified by Docket ID No. EPA-R01-
OAR-2025-0076 at https://www.regulations.gov, or via email to
[email protected]. Or comments submitted at Regulations.gov,
follow the online instructions for submitting comments. Once submitted,
comments cannot be edited or removed from Regulations.gov. For either
manner of submission, 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. Publicly
available docket materials are available at https://www.regulations.gov
or at the U.S. Environmental Protection Agency,
[[Page 14936]]
EPA Region 1 Regional Office, Air and Radiation Division, 5 Post Office
Square--Suite 100, Boston, MA. EPA requests that if at all possible,
you contact the contact listed in the FOR FURTHER INFORMATION CONTACT
section to schedule your inspection. The Regional Office's official
hours of business are Monday through Friday, 8:30 a.m. to 4:30 p.m.,
excluding legal holidays and facility closures due to COVID-19.
FOR FURTHER INFORMATION CONTACT: Patrick Lillis, Air and Radiation
Division (Mail Code 5-MI), U.S. Environmental Protection Agency--Region
1, 5 Post Office Square, Suite 100, Boston, Massachusetts 02109-3912;
tel. (617) 918-1067, or by email at [email protected].
SUPPLEMENTARY INFORMATION: Throughout this document whenever ``we,''
``us,'' or ``our'' is used, we mean EPA.
Table of Contents
I. Background and Purpose
II. Description of State's Submittals
III. The EPA's Evaluation of Connecticut's SIP Submittals
A. 2017 Base Year Emissions Inventory
1. Point Source Emissions
2. Nonpoint Source Emissions
3. On-Road Mobile Source Emissions
4. Non-Road Source Emissions
5. Biogenic Emissions
6. EPA's Evaluation of the Base Year Emissions Inventory
IV. Proposed Action
V. Statutory and Executive Order Reviews
I. Background and Purpose
Ozone is one of the six common air pollutants identified in the
Clean Air Act. Ground-level ozone forms when nitrogen oxides
(NOX) and volatile organic compounds (VOC) react in the
presence of sunlight. Referred to as ozone precursors, these two
pollutants are emitted by many types of pollution sources, including
motor vehicles, power plants, industrial facilities, and nonpoint \1\
sources. Scientific evidence indicates that adverse human health
effects occur following exposure to ozone. These effects are more
pronounced in children and adults with lung disease. Breathing air
containing ozone can reduce lung function and inflame airways, which
can increase respiratory symptoms and aggravate asthma or other lung
diseases. In 1979, in response to this scientific evidence, EPA
promulgated the first ozone NAAQS, the 0.12 parts per million (ppm) 1-
hour ozone NAAQS.\2\
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\1\ Nonpoint sources are also sometimes referred to as area
sources.
\2\ See 44 FR 8202 (Feb. 8, 1979).
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EPA has strengthened the ozone NAAQS over the years. In 1997, EPA
promulgated a revised ozone NAAQS of 0.08 ppm, averaged over eight
hours, which it determined was more protective of public health than
the 1979 standard.\3\ In 2008, EPA revised the 8-hour ozone NAAQS from
0.08 to 0.075 ppm.\4\ In 2015, the Agency further strengthened the 8-
hour ozone NAAQS to 0.070 ppm.\5\
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\3\ See 62 FR 38856 (July 18, 1997).
\4\ See 73 FR 16436 (Mar. 27, 2008).
\5\ See 80 FR 65292 (Oct. 26, 2015).
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Effective August 3, 2018, the EPA designated as nonattainment any
area that was violating the 2015 8-hour ozone NAAQS based on the three
most recent years (2014-2016) of air monitoring data.\6\ With that
rulemaking, the Connecticut portion of the New York-Northern New
Jersey-Long Island NY-NJ-CT area was originally designated as a
moderate ozone nonattainment area. This area is herein referred to as
the Connecticut portion of the NY-NJ-CT area. Additionally, in that
rulemaking, the Greater Connecticut area was originally designated as a
Marginal ozone nonattainment area. Effective November 7, 2022, the EPA
reclassified the Greater Connecticut area under the CAA from
``Marginal'' to ``Moderate'' for the 2015 8-hour ozone NAAQS.\7\ Areas
that were designated as moderate nonattainment were required to attain
the 2015 8-hour ozone NAAQS no later than August 3, 2024, based on
2021-2023 monitoring data. Effective July 25, 2024, the EPA published a
final rule granting a voluntary reclassification request to redesignate
the Connecticut portion of the NY-NJ-CT area to Serious nonattainment
for the 2015 8-hour ozone NAAQS.\8\ And effective July 29, 2024, EPA
published a final rule granting a voluntary reclassification request to
redesignate the Greater Connecticut area to Serious nonattainment for
the 2015 8-hour ozone NAAQS.\9\ Serious areas are required to attain
the 2015 8-hour ozone NAAQS as expeditiously as practicable, but no
later than nine years from the date of the initial designation as
nonattainment, i.e., by August 3, 2027.\10\ While EPA has since
reclassified both nonattainment areas in Connecticut to Serious for the
2015 8-hour ozone NAAQS, Connecticut must still meet the CAA
requirements applicable to Marginal ozone nonattainment areas.
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\6\ See 83 FR 25776, 25792 (June 4, 2018).
\7\ See 87 FR 60897 (October 7, 2022).
\8\ See 89 FR 60314 (July 25, 2024).
\9\ See 89 FR 60827 (July 29, 2024).
\10\ See 40 CFR 51.1303
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This proposed rule addresses only the base year inventory
requirements related to the Marginal nonattainment classification. The
CAA and its implementing regulations--in particular, the 2015 ozone
NAAQS SIP Requirements Rule,\11\ codified at 40 CFR part 51, subpart
CC--establish several requirements for ozone nonattainment areas.
Section 172(c)(3) of the CAA, which applies generally to states with
areas classified as nonattainment for any NAAQS, requires submission of
comprehensive, accurate, and current inventories of actual emissions
from all sources of relevant pollutants in Marginal nonattainment
areas.\12\ Specific to areas classified as Marginal ozone
nonattainment, section 182(a)(1) requires states to submit a base year
inventory of ozone precursors (NOX and VOC).
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\11\ See 83 FR 62998 (Dec. 6, 2018). The SIP Requirements Rule
established implementation requirements for the 2015 ozone NAAQS,
including requirements for base year emissions inventories.
\12\ See 42 U.S.C. 7502(c)(3).
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Emissions inventories provide data that inform a variety of air
quality planning tasks. States use emissions inventories to establish
baseline emissions levels, calculate emissions reduction targets needed
to attain the NAAQS, determine emissions inputs for ozone air quality
modeling analyses, and track emissions over time to determine progress
toward achieving air quality and emissions reduction goals. EPA has
issued guidance to assist states in developing their emission
inventories; states retain the discretion to adopt approaches on a
case-by-case basis that differ from that guidance where
appropriate.\13\
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\13\ U.S. EPA, ``Emissions Inventory Guidance for Implementation
of Ozone and Particulate Matter National Ambient Air Quality
Standards (NAAQS) and Regional Haze Regulations,'' EPA-454/B-17-002
at 1 (May 2017) (hereinafter, ``2017 Emissions Inventory
Guidance'').
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II. Description of State's Submittals
On May 3, 2024, Connecticut Department of Energy and Environmental
Protection (CT DEEP) submitted a 2017 base year emissions inventory of
ozone precursors for all areas of the State. A copy of the 2017 base
year inventory is located in the docket of this proposed rulemaking.
III. The EPA's Evaluation of Connecticut's SIP Submittals
A. 2017 Base Year Emissions Inventory
Under CAA sections 172(c)(3) and 182(a)(1), Connecticut must submit
a comprehensive, accurate, and current accounting of actual emissions
of ozone precursors from all sources (point,
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nonpoint, on-road and nonroad mobile sources, and biogenic emissions)
in both the Connecticut portion of the NY-NJ-CT area and the Greater
Connecticut area. EPA's SIP Requirements Rule specifies that the
inventory year shall be selected consistent with the baseline year for
the Reasonable Further Progress (RFP) plan under 40 CFR 51.1210(a),\14\
which EPA identified as 2017.\15\ The rule also requires states to
report ``ozone season day emissions'' in the base year inventory,\16\
as described in other EPA regulations: ``Ozone season day emissions
means an average day's emissions for a typical ozone season work
weekday. The state shall select, subject to EPA approval, the
particular month(s) in the ozone season and the day(s) in the work week
to be represented, considering the conditions assumed in the
development of RFP plans and/or emissions budgets for transportation
conformity.'' \17\ Based on EPA's 2017 Emissions Inventory Guidance for
Implementation of Ozone and Particulate Matter National Ambient Air
Quality Standards (NAAQS) and Regional Haze Regulations (2017 Emissions
Inventory Guidance), the selected ozone season day should be
representative of the conditions leading to nonattainment.\18\
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\14\ See 40 CFR 51.1315(a).
\15\ See 83 FR 62998, 63005.
\16\ See 40 CFR 51.1315(c).
\17\ See 40 CFR 51.1300(q).
\18\ See 2017 Emissions Inventory Guidance, 75.
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On May 3, 2024, Connecticut submitted to EPA as a SIP revision
request an emissions inventory of ozone precursors for 2017. The
inventory was submitted to meet the CAA section 182(a)(3)(A) obligation
to develop a base year inventory. The State conducted a public comment
process on the inventory which concluded on January 26, 2024. The
inventories include emission estimates in tons per summer day and
represent emissions estimates from stationary and mobile source
categories during a typical summer day when ozone formation is highest.
The ozone emissions inventory catalogs NOX and VOC emissions
because these pollutants are precursors to ozone formation.
Connecticut's 2017 emissions inventory contains emission estimates at
the county level and summed to the geographic areas that correspond to
the State's two Serious ozone nonattainment areas.
We propose to find that the air emission estimates for these
sources were adequately accounted for in Connecticut's 2017 base year
emissions inventory. The methodology used to calculate emissions for
each source category followed relevant EPA guidance, most notably the
May 2017 guidance entitled ``Emissions Inventory Guidance for
Implementation of Ozone and Particulate Matter National Ambient Air
Quality Standards and Regional Haze Regulations,'' \19\ used
appropriate, documented emission factors, or relied on emission
estimates prepared for EPA's National Emissions Inventory. Furthermore,
the inventory submittal is sufficiently documented as to the techniques
used to prepare the emission estimates.
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\19\ See 2017 Emissions Inventory Guidance.
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Table 1 shows the emissions by source category, in tons per summer
day (tpsd), from the 2017 base year emission inventory for each of the
State's two nonattainment areas.
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\20\ See CT DEEP's 2017 Emission Inventory Submittal, 1-15.
Table 1--Emissions Inventory Summary for Connecticut's Nonattainment Areas
[Tons/summer day] \20\
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CT portion of NY-NJ-CT area Greater CT area
Source ----------------------------------------------------------------
VOC NOX VOC NOX
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Point.......................................... 3.6 14.0 1.1 10.2
Nonpoint....................................... 52.7 6.9 53.0 6.0
Onroad......................................... 20.0 25.5 18.1 22.2
Nonroad........................................ 16.6 19.0 13.5 15.4
Biogenic....................................... 168.3 0.8 308.8 1.7
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Totals..................................... 261.3 66.2 394.5 55.6
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1. Point Source Emissions
Point sources are large, stationary, identifiable sources of
emissions that release pollutants into the atmosphere. The SIP
Requirements Rule provides that emissions from point sources shall be
reported according to the thresholds of EPA's Air Emissions Reporting
Requirements (AERR).\21\ The 2017 Emissions Inventory Guidance directs
those preparing point source inventories to volume 2 of the Emissions
Inventory Improvement Program technical report series for information
on point source inventory methodology.\22\ This resource describes the
three principal methods for estimating point source emissions as source
testing, mass balance calculations, and emission factors, with a fourth
method utilizing engineering calculations if the principal methods are
not possible.\23\
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\21\ See 40 CFR 51.1315(d).
\22\ See 2017 Emissions Inventory Guidance, 81-82.
\23\ U.S. EPA, EIIP Technical Report Series Vol. II, Ch. 1:
``Introduction to Stationary Point Source Emission Inventory
Development'' (May 2001), 1.4-1--1.4-3.
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Since 2009, Connecticut requires all Title V sources that have a
Title V permit or that have been specifically requested to file by CT
DEEP to submit an emissions statement. Beginning in 2014, companies
were required to submit their emissions statements electronically via
CT DEEP's software application, EMIT. Ozone precursor emissions are
collected using EMIT. The 2017 stationary source inventory is primarily
based on the emissions statement submittals, which reported the
source's actual 2017 emissions signed by a corporate officer who
attested to the accuracy of their calculations. Facility data for the
eighty-three (83) Connecticut sites are recorded in Section 2.1 of CT
DEEP's 2017 emissions inventory submittal that is located in the docket
of this proposed rulemaking. Since Connecticut's base year inventory is
consistent with the reporting thresholds in the AERR and uses methods
for estimating emissions recommended by EPA guidance,\24\ the base year
inventory adequately addresses emissions from the point source
category.
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\24\ See CT DEEP's 2017 Emission Inventory Submittal, 2-5.
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2. Nonpoint Source Emissions
Nonpoint or area source emission estimates are made for small,
stationary sources of air pollution that do not emit much individually,
but do have significant emissions collectively. Examples include
gasoline stations, residential heating, and fuel combustion.
Connecticut's area source emissions inventory identifies the source
categories for which the State relied upon EPA's estimates, provides
information on any adjustments made to EPA estimates, and notes which
categories' emission estimates were prepared by the State. The
inventory also explains how double counting between emissions from
facilities inventoried as individual point sources were excluded from
the area source emission estimates.\25\ Therefore, the base year
inventory adequately addresses emissions from the nonpoint source
category.
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\25\ See CT DEEP's 2017 Emission Inventory Submittal, Section 4.
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3. On-Road Mobile Source Emissions
On-road mobile sources are motor vehicles (e.g. automobiles, buses,
and trucks) that travel on local roads and highways. A motor vehicle is
defined in 40 CFR 51.50 \26\ as ``any self-propelled vehicle used to
carry people or property on a street or highway''. Emissions from on-
road vehicles are the result of several processes, including the
combustion of fuel while vehicles are starting, idling, or moving; the
evaporation of fuel from the fuel system and during refueling; as well
as from the wearing of brakes and tires.
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\26\ See 40 CFR 51.50
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To estimate on-road emissions in 2017, CT DEEP ran EPA's model
MOVES2014b for all eight Connecticut counties in inventory-mode using
established annual and summer day input data. EPA's Motor Vehicle
Emission Simulator (MOVES) is a state-of-the-science emission modeling
system that estimates emissions for mobile sources at the national,
county, and project level for criteria air pollutants, greenhouse
gases, and air toxics. Vehicles are classified in MOVES according to
thirteen source types and five Highway Performance Monitoring System
(HPMS) vehicle types. Part 3.1.1 of CT DEEP's 2017 emission inventory
submittal provides an explanation and the basis for the input
parameters used in MOVES2014b for the calculation and development of
this emissions inventory. CT DEEP's 2017 emission inventory is located
in the docket of this proposed rulemaking.
Connecticut's on-road mobile source emissions inventory methodology
follows the SIP Requirements Rule \27\ as well as EPA's 2017 Emissions
Inventory Guidance.\28\ Therefore, the base year inventory adequately
addresses emissions from the on-road mobile source category.
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\27\ See 83 FR 62998.
\28\ See 2017 Emissions Inventory Guidance, 89-90.
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4. Non-Road Source Emissions
Non-road mobile sources are comprised of non-road engines and non-
road vehicles, which are respectively defined in 40 CFR 51.50 \29\ as
``an internal combustion engine (including fuel system) that is not
used in a motor vehicle or a vehicle used solely for competition, or
that is not affected by sections 111 or 202 of the Clean Air Act'' \30\
and ``a vehicle that is run by a non-road engine and that is not a
motor vehicle or a vehicle used solely for competition.'' \31\ These
sources include vehicles, engines, and equipment used for construction,
agriculture, recreation, and many other purposes. The equipment must
either move under its own power or be capable of being moved from site
to site. Emissions from non-road vehicles come from both exhaust and
non-exhaust processes, including the combustion of fuel while vehicles
are starting, idling, or moving, as well as from the evaporation of
fuel from the fuel system and during refueling.
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\29\ See 40 CFR 51.50.
\30\ See CAA Section 111 and 202.
\31\ See 40 CFR 51.50.
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To estimate non-road emissions in 2017, CT DEEP ran MOVES2014b for
all eight Connecticut counties in inventory-mode using established
annual and summer day input data. Connecticut's 2017 base year
inventory used EPA's MOVES-Nonroad model to estimate emissions from
nonroad mobile sources in the Connecticut portion of the NY-NJ-CT
Nonattainment area as well as the Greater Connecticut Nonattainment
Area, except for emissions from aviation, locomotives, and commercial
marine vessels (CMV). Connecticut adopted EPA's 2017 NEI estimates for
aviation, locomotive, and CMV emissions. See section 3.3 through 3.5 in
CT's 2017 emission inventory for more information on aviation,
locomotives, and CMV emission calculations. CT DEEP's 2017 emission
inventory is located in the docket of this proposed rulemaking.
Therefore, the base year inventory adequately addresses emissions from
the non-road mobile source category.
5. Biogenic Emissions
Biogenic emissions come from natural sources. Connecticut included
a 2017 inventory of biogenic emissions separate from the anthropogenic
portion of the inventory. Connecticut accepted the EPA biogenic
emissions estimates as published in the 2017 NEI. For more information
on these estimates, please refer to Section 4.6 of the 2017 NEI v1
TSD.\32\ The annual estimates for this sector in 2017 are presented in
Section 5 of Connecticut's 2017 emission inventory submittal. CT DEEP's
2017 emission inventory is located in the docket of this proposed
rulemaking. Therefore, the base year inventory adequately addresses
emissions from the biogenic source category.
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\32\ See Section 4.6 of the 2017 NEI v1 TSD.
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6. EPA's Evaluation of the Base Year Emissions Inventory
Based on EPA's review and evaluation of the methodologies,
procedures, and results in Connecticut's 2017 base year emissions
inventory, we propose to find that the inventory meets the requirements
of CAA sections 172(c)(3) and 182(a)(1) and the SIP Requirements Rule.
The base year inventory is based on the most current and accurate
information that was available to the State at the time the inventory
was developed. Additionally, the 2017 inventory comprehensively
addresses all source categories in the Connecticut portion of the NY-
NJ-CT Nonattainment Area, as well as the Greater Connecticut
Nonattainment Area and was developed consistent with the relevant EPA
emissions inventory regulations, guidance, and models.
IV. Proposed Action
EPA is proposing to approve SIP submittals from the state of
Connecticut for the 2017 base year emissions inventory for the 2015 8-
hour ozone NAAQS for both the Greater Connecticut and the Connecticut
portion of the NY-NJ-CT nonattainment areas. EPA is soliciting public
comment on the issues discussed in this document or on other relevant
matters. These comments will be considered before taking final action.
Interested parties may participate in the Federal rulemaking procedure
by submitting written comments to this proposed rule by following the
instructions listed in the ADDRESSES section of this Federal Register.
V. Statutory and Executive Order Reviews
Under the Clean Air Act, the Administrator is required to approve a
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SIP submission that complies with the provisions of the Clean Air Act
and applicable Federal regulations. See 42 U.S.C. 7410(k); 40 CFR
52.02(a). Thus, in reviewing SIP submissions, EPA's role is to approve
state choices, provided that they meet the criteria of the Clean Air
Act. Accordingly, this proposed action merely approves state law as
meeting Federal requirements and does not impose additional
requirements beyond those imposed by state law. For that reason, this
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);
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 subject to Executive Order 13045 (62 FR 19885,
April 23, 1997) because it approves a state program;
Is not a significant regulatory action subject to
Executive Order 13211 (66 FR 28355, May 22, 2001); and
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.
In addition, the SIP is not approved to apply on any Indian
reservation land or in any other area where EPA or an Indian tribe has
demonstrated that a tribe has jurisdiction. In those areas of Indian
country, the 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, Nitrogen dioxide, Ozone, Reporting and recordkeeping
requirements, Volatile organic compounds.
Dated: March 20, 2025.
Karen McGuire,
Acting Regional Administrator, EPA Region 1.
[FR Doc. 2025-05910 Filed 4-4-25; 8:45 am]
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