Proposed Rule2026-02842
Air Plan Approval; Illinois; Moderate Attainment Plan Elements for the Chicago and Metro East Areas for the 2015 Ozone Standard
Primary source
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Published
February 12, 2026
Issuing agencies
Environmental Protection Agency
Abstract
The Environmental Protection Agency (EPA) is proposing to approve portions of Illinois' 2015 ozone National Ambient Air Quality Standard (NAAQS or standard) Moderate nonattainment area State Implementation Plan (SIP) submission for the Chicago and the Metro East St. Louis areas. The portions of the SIP submission that the EPA is proposing to approve are the reasonable further progress (RFP) demonstration including the associated motor vehicle emissions budgets for 2023, the motor vehicle inspection and maintenance (I/M) program, the nonattainment new source review (NNSR) program, and the updated 2017 base year emissions inventories. The EPA is proposing to approve these portions of the State's SIP submission pursuant to section 110 and part D of the Clean Air Act (CAA), and the EPA's regulations. The EPA is also initiating the adequacy process for the 2023 motor vehicle emissions budgets (budgets) for the Chicago and Metro East St. Louis Moderate ozone nonattainment RFP demonstration included in this SIP submission.
Full Text
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<title>Federal Register, Volume 91 Issue 29 (Thursday, February 12, 2026)</title>
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[Federal Register Volume 91, Number 29 (Thursday, February 12, 2026)]
[Proposed Rules]
[Pages 6568-6575]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2026-02842]
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ENVIRONMENTAL PROTECTION AGENCY
40 CFR Part 52
[EPA-R05-OAR-2024-0617; EPA-R05-OAR-2024-0618; FRL-13163-01-R5]
Air Plan Approval; Illinois; Moderate Attainment Plan Elements
for the Chicago and Metro East Areas for the 2015 Ozone Standard
AGENCY: Environmental Protection Agency (EPA).
ACTION: Proposed rule.
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SUMMARY: The Environmental Protection Agency (EPA) is proposing to
approve portions of Illinois' 2015 ozone National Ambient Air Quality
Standard (NAAQS or standard) Moderate nonattainment area State
Implementation Plan (SIP) submission for the Chicago and the Metro East
St. Louis areas. The portions of the SIP submission that the EPA is
proposing to approve are the reasonable further progress (RFP)
demonstration including the associated motor vehicle emissions budgets
for 2023, the motor vehicle inspection and maintenance (I/M) program,
the nonattainment new source review (NNSR) program, and the updated
2017 base year emissions inventories. The EPA is proposing to approve
these portions of the State's SIP submission pursuant to section 110
and part D of the Clean Air Act (CAA), and the EPA's regulations. The
EPA is also initiating the adequacy process for the 2023 motor vehicle
emissions budgets (budgets) for the Chicago and Metro East St. Louis
Moderate ozone nonattainment RFP demonstration included in this SIP
submission.
DATES: Comments must be received on or before March 16, 2026.
ADDRESSES: Submit your comments, identified by Docket ID No. EPA-R05-
OAR-2024-0617 or EPA-R05-OAR-2024-0618 at <a href="https://www.regulations.gov">https://www.regulations.gov</a>,
or via email to <a href="/cdn-cgi/l/email-protection#f594878794db869487949db5908594db929a83"><span class="__cf_email__" data-cfemail="264754544708554754474e6643564708414950">[email protected]</span></a>. For comments submitted at
<a href="http://Regulations.gov">Regulations.gov</a>, follow the online instructions for submitting
comments. Once submitted, comments cannot be edited or removed from the
docket. The EPA may publish any comment received to its public docket.
Do not submit to the EPA's docket at <a href="https://www.regulations.gov">https://www.regulations.gov</a> any
information you consider to be Confidential Business Information (CBI),
Proprietary Business Information (PBI), 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, PBI, or multimedia submissions,
and general guidance on making effective comments, please visit <a href="https://www.epa.gov/dockets/commenting-epa-dockets">https://www.epa.gov/dockets/commenting-epa-dockets</a>.
FOR FURTHER INFORMATION CONTACT: Nicole Naber, Air and Radiation
Division (AR-18J), Environmental Protection Agency, Region 5, 77 West
Jackson Boulevard, Chicago, Illinois 60604, (312) 886-6609,
<a href="/cdn-cgi/l/email-protection#1977787b7c6b3777707a76757c597c6978377e766f"><span class="__cf_email__" data-cfemail="741a151611065a1a1d171b1811341104155a131b02">[email protected]</span></a>. The EPA Region 5 office is open from 8:30 a.m. to
4:30 p.m., Monday through Friday, excluding Federal holidays.
SUPPLEMENTARY INFORMATION: Throughout this document whenever ``we,''
``us,'' or ``our'' is used, we mean the EPA.
I. Background
On December 28, 2015, the EPA promulgated a revised 8-hour ozone
NAAQS of 0.070 parts per million (ppm).\1\ Promulgation of a revised
NAAQS triggers a requirement for the EPA to designate all areas of the
country as nonattainment, attainment, or unclassifiable for the NAAQS.
For the ozone NAAQS, this also involves classifying any nonattainment
areas at the time of designation.\2\ Ozone nonattainment areas are
classified based on the severity of their ozone levels as determined by
area's ``design value,'' which represents air quality in the area for
the most recent three years. The classifications for ozone
nonattainment areas are Marginal, Moderate, Serious, Severe, and
Extreme.\3\
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\1\ 80 FR 65292, October 26, 2015, codified at 40 CFR 50.19.
\2\ CAA sections 107(d)(1) and 181(a)(1).
\3\ CAA section 181(a)(1).
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Areas that the EPA designates nonattainment for the ozone NAAQS are
subject to the general nonattainment area planning requirements of CAA
section 172 and the ozone-specific planning requirements of CAA section
182. Ozone nonattainment areas in the lower classification levels have
fewer and/or less stringent mandatory air quality planning and control
requirements than those in higher classifications. In the EPA's
December 6, 2018 (83 FR 62998), rule, ``Implementation of the 2015
National Ambient Air Quality Standards for Ozone: Nonattainment Area
State Implementation Plan Requirements,'' known as the ``SIP
Requirements Rule,'' the EPA set forth nonattainment area requirements
for the 2015 ozone NAAQS. These requirements are codified at 40 CFR
part 51 subpart CC. For Marginal areas, a State is required to submit a
baseline emissions inventory, adopt provisions into the SIP requiring
emissions statements from stationary sources, and implement a
nonattainment new source review program for the relevant ozone
NAAQS.\4\ For Moderate areas, a State needs to comply with the Marginal
area requirements, plus additional Moderate area requirements,
including the requirement to submit a modeled demonstration that the
area will attain the NAAQS as expeditiously as practicable but no later
than six years after designation, the requirement to submit an RFP
plan, the requirement to adopt and implement certain emissions
controls, such as Reasonably Available Control Technology (RACT) and a
Basic I/M program, and the requirement for greater emissions offsets
for new or modified major stationary sources under the State's NNSR
program.
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\4\ CAA section 182(a).
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Effective June 4, 2018, the EPA designated the Chicago and Metro
East St. Louis areas as Marginal nonattainment. The Chicago area
includes Cook County, DuPage County, Grundy County, Kane County,
Kendall
[[Page 6569]]
County, Lake County, McHenry County, and Will County, and the Metro
East area includes Madison County, Monroe County, and St. Clair County.
Under CAA section 181(b)(2), Marginal nonattainment areas that fail to
attain the 2015 ozone NAAQS by the applicable attainment date will be
reclassified as Moderate by operation of law upon the effective date of
the final determination. For Chicago and Metro East, the deadline was
August 3, 2021.
On October 7, 2022 (87 FR 60897), the EPA determined that the
Chicago and Metro East areas failed to attain the 2015 ozone NAAQS by
the August 3, 2021, deadline, resulting in the reclassification of the
areas from Marginal to Moderate ozone attainment. In that action, the
EPA established January 1, 2023, as the due date for Illinois to submit
all Moderate area nonattainment plan SIP requirements applicable to
newly reclassified areas. More recently, on December 17, 2024 (89 FR
101901), the EPA determined the areas did not attain the standards by
the Moderate attainment date, and the areas were reclassified as
Serious; however, this action is only addressing Moderate elements.
II. Evaluation of Illinois' Submittals
The Illinois Environmental Protection Agency (Illinois EPA)
submitted SIP revisions on December 18, 2024, to address Moderate area
requirements for the Chicago and Metro East areas under the 2015 ozone
NAAQS. These submittals contained several nonattainment plan elements,
including an updated 2017 base year emissions inventory for volatile
organic compounds (VOC) and oxides of nitrogen (NO<INF>X</INF>) and a
15% RFP plan with 2023 VOC and NO<INF>X</INF> motor vehicle emissions
budgets, an I/M program certification, and an NNSR certification. The
submissions also included an attainment demonstration, a reasonably
available control measures demonstration, and contingency measures,
which are not being addressed in this action. Illinois' SIP submissions
and associated supporting documents are available in the docket for
this action.
A. 2017 Base Year Emissions Inventory
1. Background
CAA sections 172(c)(3) and 182(a)(1), 42 U.S.C. 7502(c)(3) and
7511a(a)(1), require States to develop and submit, as SIP revisions,
comprehensive, accurate, and complete emissions inventories for all
areas designated as nonattainment for the ozone NAAQS. The specific
emissions inventory requirements are codified at 40 CFR 51.1315, and
the term ``base year inventory'' is defined at 51.1300(p). For ozone,
the base year inventory is an estimation of actual emissions of VOC and
NO<INF>X</INF> from all sources within the boundaries of the
nonattainment area.
The regulation at 40 CFR 51.1315(a) requires that the inventory
year be selected consistent with the baseline year for the RFP plan as
required by 40 CFR 51.1310(b), which states that the baseline emissions
inventory shall be the emissions inventory for the most recent calendar
year for which a complete triennial inventory is required to be
submitted to the EPA under the provisions of subpart A of 40 CFR part
51, Air Emissions Reporting Requirements, 40 CFR 51.1 through 50. For
areas designated as nonattainment in 2018, the most recent triennial
inventory year conducted for the National Emissions Inventory (NEI)
pursuant to the Air Emissions Reporting Requirements (AERR) rule is
2017.\5\
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\5\ 83 FR 62998 through 63036 at 63005, December 6, 2018.
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Further, 40 CFR 51.1315(c) requires emissions values included in
the base year inventory to be actual ozone season day emissions as
defined by 40 CFR 51.1300(q), which states: ``Ozone season day
emissions mean an average day's emissions for a typical ozone season
work weekday. The State shall select, subject to the EPA approval, the
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.''
On October 22, 2020, Illinois EPA submitted a SIP revision
addressing the emissions inventory requirement of CAA section
182(a)(1). The EPA approved Illinois' 2017 base year emissions
inventories for the Chicago area on August 15, 2023 (88 FR 55383).
2. Illinois' Emission Inventory Submittal
As part of Illinois' SIP revision request, Illinois EPA updated the
2017 base year emissions inventories to incorporate improved emissions
estimates where available. In Illinois' original base year emissions
inventory submittal, Illinois EPA used the 2016v1 modeling platform to
generate emissions data for the point and nonpoint sectors and
MOVES2014 to generate emissions data for the on-road and nonroad
sectors. Illinois EPA updated the 2017 base year emissions inventories
for the Chicago and Metro East areas using the 2016v1 modeling platform
for point and nonpoint sectors and MOVES3 for nonroad and on-road
sectors. Illinois EPA did not update biogenic emissions estimates.
Illinois EPA converted annual point and nonpoint values to tons per
day (tpd) following the same procedure as was used when preparing the
original 2017 base year emissions inventories. Illinois EPA extracted
data from the 2016v1 modeling platform to calculate the ratio of July
emissions to total annual emissions for each county by sector.
Table 1, below, shows the updated 2017 ozone season day emissions
in tons per ozone season day of NO<INF>X</INF> and VOC for the Chicago
and Metro East nonattainment areas, respectively.
Table 1--2017 Base Year NOX and VOC Emissions for the Chicago and Metro East Nonattainment Areas
[Tons/day]
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Point On-road Off-road
Area Pollutant source Area source mobile mobile Total
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Chicago...................... NOX............. 66.39 101.36 208.20 53.34 429.29
VOC............. 45.74 207.57 58.20 49.99 361.50
Metro East................... NOX............. 10.65 8.72 17.44 5.25 42.06
VOC............. 8.62 18.94 6.81 3.82 38.19
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[[Page 6570]]
3. Analysis of Illinois' 2017 Base Year Emission Inventory
EPA has reviewed Illinois' updated 2017 base year emissions
inventory for consistency with sections 172(c)(3) and 182(a)(1) of the
CAA and the EPA's emission inventory requirements. The selection of
2017 as the base year comports with the RFP baseline year requirements
set forth in the SIP Requirements Rule and codified at 40 CFR
51.1310(b).
Illinois EPA documented the procedures used to estimate the
emissions for each of the major source types. The documentation of the
emission estimation procedures is sufficient to determine that Illinois
followed acceptable procedures to estimate the emissions. Accordingly,
the EPA concludes that Illinois has developed inventories of
NO<INF>X</INF> and VOC emissions that are comprehensive and complete
and is therefore proposing to approve Illinois' updated 2017 base year
emissions inventory for the Chicago and Metro East areas under the 2015
ozone NAAQS.
B. I/M Program
1. Background
CAA section 182(b)(4) requires States with ozone nonattainment
areas classified as Moderate to implement a Basic motor vehicle I/M
program. The goal of I/M programs is to identify and repair high-
emitting vehicles to improve air quality in areas that are not
attaining the NAAQS.\6\ The CAA generally requires I/M programs for
areas across the country that meet certain criteria, such as air
quality status, population, and/or geographic location. The CAA also
directed the EPA to establish minimum performance standards for Basic
and Enhanced I/M programs. States have flexibility to design their own
programs if they can show that their program is as effective as the
model program used in the respective performance standard. The EPA's
requirements for Basic and Enhanced I/M programs are found in 40 CFR
part 51, subpart S.
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\6\ For more information, see Overview of Vehicle Inspection and
Maintenance (I/M) Programs (EPA-420-F-21-067, October 2021) at
<a href="https://nepis.epa.gov/Exe/ZyPDF.cgi?Dockey=P1013CC0.pdf">https://nepis.epa.gov/Exe/ZyPDF.cgi?Dockey=P1013CC0.pdf</a>.
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Illinois EPA has been operating an enhanced I/M program in the
Chicago and Metro East areas since February 22, 1999 (64 FR 8517), with
a subsequent approval on August 13, 2014 (79 FR 47377). These EPA-
approved I/M program requirements, that are incorporated into the
Illinois SIP, remain in place in both the Chicago and Metro East areas.
2. Illinois' I/M Certification
Consistent with the I/M regulations, a State with an existing I/M
program would need to conduct and submit a performance standard
modeling (PSM) analysis as well as make any necessary program revisions
as part of their Moderate area SIP submission to ensure that their I/M
program is operating at or above the Basic I/M performance standard
level for the 2015 ozone NAAQS. When certifying that an existing I/M
program meets applicable I/M requirements for a new NAAQS, it is
necessary that the State ensures that an I/M program reflects the I/M
rule's required elements for a Basic or Enhanced I/M program and the
applicable classification for the new ozone NAAQS. If an I/M program
for a previous NAAQS contains the required elements for a new NAAQS
(e.g., such as on-road mobile source testing for an Enhanced I/M
program) then the State may determine through the performance standard
modeling analysis that an existing SIP-approved program would meet the
applicable performance standard for purposes of the 2015 ozone NAAQS
without modification.
Illinois EPA is certifying that the existing SIP-approved I/M
programs meet the Basic I/M program requirements of CAA section
182(b)(4) for the Chicago and Metro East areas under the 2015 ozone
NAAQS. The Illinois Vehicle Emission Inspection Law of 2005(625 ILCS 5/
13C) authorizes the State to implement I/M programs to reduce to reduce
air pollution from motor vehicles in these areas. In addition, the
requirements for the State's I/M programs are found in the Illinois
Administrative Code (Ill. Adm. Code) Title 35, Parts 240 and 276. The
Illinois I/M programs require on-board diagnostic (OBD) testing of
gasoline-fueled and hybrid motor vehicles up to 8500 pounds gross
vehicle weight rating (GVWR) that are 1996 model year (MY) and newer
but more than four MYs old, as well as the OBD testing of gasoline-
fueled and hybrid vehicles between 8501 and 14,000 pounds GVWR that are
2007 MY and newer but more than four MYs old.
In addition, Illinois EPA conducted an I/M PSM analysis to
demonstrate that Illinois' current I/M program continues to exceed the
level of the EPA's Enhanced performance standard for areas designated
and classified under the 8-hour ozone standard, as detailed at 40 CFR
51.351(i)(13), which states that the actual I/M program must achieve
the same or lower emissions levels of NO<INF>X</INF> and VOCs as the
Federal model Enhanced program to within 0.02 grams/mile (g/m).
Illinois EPA performed the modeling analysis using the EPA's mobile
source emissions model, MOVES4, which was the latest model version at
the time the analysis was started. The performance standard modeling
analysis began after the mobile emissions modeling analyses conducted
to prepare other elements of the SIP submission. This modeling was
conducted for analysis year 2023 in accordance with the EPA's technical
guidance: ``Performance Standard Modeling for New and Existing Vehicle
Inspection and Maintenance (I/M) Programs Using the MOVES Mobile Source
Emissions Model'', EPA-420-B-22-034, October 2022,\7\ (October 2022
Performance Standard Modeling Guidance).
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\7\ <a href="https://nepis.epa.gov/Exe/ZyPDF.cgi?Dockey=P1015S5C.pdf">https://nepis.epa.gov/Exe/ZyPDF.cgi?Dockey=P1015S5C.pdf</a>.
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Table 2 below shows the results of Illinois EPA's modeling analysis
comparing the average fleet emission rates of the current I/M program
to that of the Enhanced I/M performance standard benchmark program for
both the Chicago and Metro East nonattainment areas, respectively. In
all cases, the analysis shows that the emission reductions from
Illinois' actual I/M program exceed the emission reductions modeled for
the benchmark program of the Enhanced I/M performance standard to
within 0.02 g/m.
[[Page 6571]]
Table 2--Summary of July Weekday NOX and VOC Emission Rates for the Chicago and Metro East Nonattainment Areas
[g/m]
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Enhanced I/M Does existing I/M
Area Pollutant Existing I/ Enhanced I/ benchmark with program meet the I/M
M program M benchmark 0.02 g/m buffer performance standard?
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Chicago....................................... NOX.............................. 0.984 1.002 1.022 Yes.
VOC.............................. 0.538 0.533 0.553 Yes.
Metro East.................................... NOX.............................. 0.527 0.533 0.553 Yes.
VOC.............................. 0.302 0.297 0.317 Yes.
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2. Evaluation of Illinois' I/M Program
At the Moderate classification for the 2015 ozone NAAQS, the
Chicago and Metro East areas are only required to implement Basic I/M.
However, these areas continue to implement Enhanced I/M programs as
adopted into the SIP under prior ozone NAAQS. The EPA's October 2022
Performance Modeling Guidance addresses the situation where a State may
need to demonstrate that an area's current Enhanced I/M program
satisfies the Basic I/M SIP requirement: ``[I]t is reasonable to
presume that if an I/M program meets the Enhanced performance standard,
then it would also meet the Basic performance standard so long as the
analysis years are appropriate for the two 8-hour ozone standards in
question.'' \8\ The guidance goes on to identify the attainment date as
the appropriate analysis year for areas that have been reclassified.\9\
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\8\ October 2022 Performance Standard Modeling Guidance, p. 10.
\9\ Ibid.
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The Moderate attainment date for the Chicago and Metro East areas
is August 3, 2024. However, because that date falls in the middle of
the ozone season, 2023 is the year that will be used to determine
whether the area achieves attainment by the attainment date. Therefore,
Illinois appropriately chose 2023 as the analysis year to be consistent
with the year in which attainment would be determined.
EPA has reviewed Illinois' I/M program submittals and determined
that the emission reductions from the current Chicago and Metro East I/
M programs meet or exceed the Basic I/M performance standard. Illinois
EPA documented that the modeling analysis was conducted in accordance
with the EPA's October 2022 Performance Modeling Guidance. Therefore,
since the Chicago and Metro East I/M programs meet the applicable I/M
performance requirements and also meet the Basic I/M requirements of
CAA section 182(b)(4) and 40 CFR 51 subpart S, we are proposing to
approve Illinois' I/M program SIP element for the Chicago and Metro
East Moderate nonattainment areas under the 2015 ozone NAAQS.
C. 15% RFP Plan
1. Background
The CAA requires that States with areas designated as nonattainment
for ozone achieve RFP toward attainment of the ozone NAAQS. CAA section
172(c)(2) contains a general requirement that nonattainment plans must
provide for emissions reductions that meet RFP. For areas classified
Moderate, section 182(b)(1) imposes a more specific RFP requirement
that a State is required to meet through a 15% reduction in VOC
emissions from the baseline anthropogenic emissions within 6 years
after November 15, 1990.
The SIP Requirements Rule addressed, among other things, RFP
requirements as they apply to areas designated nonattainment and
classified as Moderate for the 2015 ozone NAAQS.\10\ RFP requirements
under the 2015 ozone NAAQS are codified at 40 CFR 51.1310. The EPA
interprets the 15% VOC emission reduction requirement in CAA section
182(b)(1) such that a State that has already met the 15% requirement
for VOC and NO<INF>X</INF> for an area under either the 1-hour ozone
NAAQS or a prior 8-hour ozone NAAQS would not have to fulfill that
requirement through reductions of VOC again. Instead, States with such
areas must obtain 15% ozone precursor emission reductions from VOC and/
or NO<INF>X</INF> over the first 6 years after the baseline year for
the 2015 ozone NAAQS. Illinois previously met the 15% VOC reduction
requirement of CAA section 182(b)(1) for the Chicago and Metro East
areas under the 1-hour ozone NAAQS. Therefore, the State may rely upon
both VOC and NO<INF>X</INF> emissions reductions to meet the RFP
requirement for the 2015 ozone NAAQS.
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\10\ 83 FR 62998 through 63036 at 63004, December 6, 2018.
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The SIP Requirements Rule specifies that the baseline emissions
inventory for RFP plans shall be the most recent calendar year prior to
designation for which a complete triennial inventory is required to be
submitted to the EPA under the provisions of subpart A of 40 CFR part
51, AERR, 40 CFR 51.1 through 50. For areas designated as nonattainment
in 2018, the most recent triennial inventory year conducted for the NEI
pursuant to the AERR rule is 2017. The rule also allows the use of an
alternative RFP baseline year that corresponds with the year of the
effective date of an area's designation, i.e., 2018 for areas
designated nonattainment in 2018.\11\
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\11\ 83 FR 62998 through 63036 at 63005, December 6, 2018,
codified at 40 CFR 51.1310(b).
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States may not take credit for VOC or NO<INF>X</INF> reductions
occurring from sources outside the nonattainment area for purposes of
meeting the 15% RFP requirements of CAA sections 172(c)(2), 182(b)(1)
and 182(c)(2)(B).\12\
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\12\ 40 CFR 51.1310(a)(6).
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Except as specifically provided in CAA section 182(b)(1)(C) and (D)
and CAA section 182(c)(2)(B), all emission reductions from SIP-approved
or federally promulgated measures that occur after the baseline
emissions inventory year are creditable for purposes of the RFP
requirements in this section, provided the reductions meet the
requirements for creditability, including the need to be enforceable,
permanent, quantifiable, and surplus. Further, the Administrator has
determined that the four categories of control measures listed in CAA
section 182(b)(1)(D) are no longer required to be calculated for
exclusion in RFP analyses because due to the passage of time the effect
of these exclusions would be de minimis.\13\
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\13\ 40 CFR 51.1310(a)(7).
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2. Illinois' 15% RFP Plan
Emission Inventories
To demonstrate that the Chicago and Metro East areas have achieved
15% RFP over the 6-year attainment planning period, Illinois EPA is
using a 2017 base year inventory and a 2023 RFP inventory. The
procedures Illinois EPA
[[Page 6572]]
used to develop the 2017 base year inventory are discussed in section
I.A. of this preamble. A 2016 base year inventory was used to project
2023 emissions. The 2016 base year was selected because of meteorology,
typical ozone conditions, and average wildfire conditions. Comparing
Illinois' 2017 base year inventory to the 2016 base year inventory used
to project 2023 emissions, Illinois' 2017 base year inventory VOC and
NO<INF>X</INF> emissions are higher. Therefore, projected emissions
reductions for both pollutants in the RFP demonstration are more
conservative when compared to the 2016 inventory. For both Chicago and
Metro East, these base year emissions are substituted for 2017 data in
all cases, except for onroad emissions projections. For the Chicago
nonattainment area, the on-road mobile emissions were updated in this
document to reflect the most up to date MOVES3 modeling at the time of
analysis and motor information and were used to project 2023 emissions
from a 2019 base year. The 2019 base year was chosen as it had more
detailed modeling information for the Chicago NAA compared to 2017.
Since on-road emissions have trended downward from 2017 to 2020 based
on NEI data, the 2019 base year should have lower emissions than the
2017 base year, therefore, estimates of emissions reductions between
2023 and 2019 are less than estimates between 2023 and 2017. Thus, the
2019 base year on-road mobile emissions can be conservatively
substituted for 2017 data in all cases. For the Metro East
nonattainment area, the on-road mobile emissions were updated in this
document to reflect the most up to date MOVES3 modeling at the time of
analysis and motor information and were used to project 2023 emissions
from a 2017 base year. The primary source of data for point sources was
the source-reported 2017 annual emissions reports. Area source
emissions are estimated by multiplying an emission factor by a known
indicator of activity for a source category. The 2016v1 modeling
platform used projection methods for the 2023 emissions inventory that
are specific to the type of emissions source. In general, future
emissions are projected from the 2016 base case through running models
or adjusting base year emissions based on best estimates of changes
expected to occur. Two electrical generating units (EGUs) announced
shutdown before 2023 but after the development of the inventory;
therefore, the Eastern Regional Technical Advisory Committee provided
an EGU 16.2 beta inventory forecast for 2023 that was modified to
remove the 2023 emissions from these units.
2023 ozone season day emissions of NO<INF>X</INF> and VOC for the
Chicago and Metro East areas are shown in Table 3.
Table 3--2023 Base Year Ozone Season Emissions
[Tons/day]
----------------------------------------------------------------------------------------------------------------
Point On-road Off-road
Area Pollutant source Area source mobile mobile Total
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Chicago...................... NOX............. 66.59 93.11 150.90 53.34 345.92
VOC............. 45.80 211.45 49.00 44.61 350.86
Metro East................... NOX............. 9.14 7.48 9.87 3.28 29.76
VOC............. 7.97 18.80 4.79 2.80 34.35
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15% RFP Demonstration
Illinois EPA demonstrated that the Chicago and Metro East Areas
have achieved 15% RFP over the 6-year attainment planning period
through VOC and NO<INF>X</INF> emission reductions. Illinois has
documented Federal control measures and State measures adopted into the
Illinois SIP that are permanent and enforceable and can be used to
achieve emissions reductions. Illinois chose to count 2% VOC reductions
and 13% NO<INF>X</INF> reductions for Chicago and 3% VOC reductions and
12% NO<INF>X</INF> reductions for Metro East from 2017-2023 to meet the
15% RFP requirement. Table 4 shows the calculations used to determine
that emissions reductions in both areas are sufficient to meet the 15%
RFP requirement.
Table 4--Demonstration of 15% RFP Requirement
[Tons/day]
----------------------------------------------------------------------------------------------------------------
Area
------------------------------------
Step Description Formula Chicago Metro East
------------------------------------
NOX VOC NOX VOC
----------------------------------------------------------------------------------------------------------------
1............ 2017 Base Year .................................... 429.29 361.50 42.06 38.19.
Inventory.
2............ RFP Reductions .................................... 13% 2% 12% 3%.
totaling 15%.
3............ Emissions reductions Step 1 x Step 2..................... 55.81 7.23 5.05 1.15.
required between base
and future year.
4............ Reductions between .................................... 57.30 9.20 7.57 2.02.
2017 to 2023 from
Federal on-road
control programs.
5............ Adjustments to .................................... 1.49 1.97 2.52 0.87.
reductions Increase
for mobile source
budget.
6............ Creditable reductions Step 4-Step 5....................... 55.81 7.23 5.05 1.15.
from on-road control
programs.
7............ Compare creditable Is Step 6 >=Step 3?................. Yes Yes Yes Yes.
reductions to
determine if at least
15% reduction is
achieved.
8............ RFP Target Level...... Step 1-Step 3....................... 373.48 354.27 37.01 37.05.
9............ Projected 2023 .................................... 345.92 350.86 29.76 34.35.
emissions.
10........... Compare RFP target Is Step 8 >=Step 9?................. Yes Yes Yes Yes.
with projected 2023
emissions to
determine if RFP
requirements are met.
----------------------------------------------------------------------------------------------------------------
[[Page 6573]]
3. Evaluation of Illinois' 15% RFP Plan
EPA has reviewed Illinois' 15% RFP plan for consistency with
sections 172(c)(2) and 182(b)(1) of the CAA and 40 CFR 51.1310. The
selection of 2017 as the base year comports with the RFP baseline year
requirements set forth in the SIP Requirements Rule and codified at 40
CFR 51.1310(b). The EPA has reviewed the techniques used by Illinois to
derive the 2017 and 2023 emission estimates. Illinois documented the
procedures used to estimate the emissions for each of the major source
types. The documentation of emission estimation procedures is thorough
and adequate to determine that Illinois followed acceptable procedures
to estimate the emissions. Illinois has demonstrated that these
emission reductions are permanent and enforceable and will result in at
least 15% RFP in the Chicago and Metro East areas over the six-year
attainment planning period beginning with the 2017 base year. Thus, the
EPA is proposing to approve Illinois' 15% RFP plan for both areas for
the 2015 ozone NAAQS.
D. Motor Vehicle Emission Budgets
1. Background
Under section 176(c) of the CAA, transportation plans, programs, or
projects that receive Federal funding or support, such as the
construction of new highways, must ``conform'' to (i.e., be consistent
with) the SIP before they receive Federal funding or approval.
Conformity to the SIP means that transportation activities will not
cause or contribute to any new air quality violations, increase the
frequency or severity of any existing air quality problems, or delay
timely attainment or any required interim emissions reductions or any
other milestones. Regulations at 40 CFR part 93 subpart A set forth the
EPA policy, criteria, and procedures for demonstrating and ensuring
conformity of transportation activities to a SIP.
Transportation conformity is a requirement for nonattainment and
maintenance areas, as defined in 40 CFR 93.101. The budget in a State's
SIP serves as a ceiling on emissions from an area's planned
transportation system (see definition of ``motor vehicle emissions
budget'' in 40 CFR 93.101 and how the term is used in 40 CFR 93.109 and
93.118).
2. VOC and NO<INF>X</INF> Budgets for the Chicago and Metro East Areas
The RFP plan includes VOC and NO<INF>X</INF> budgets for the
Chicago and Metro East areas for 2023, the milestone year for RFP.
These inventories were developed using up-to-date assumptions about
vehicles mile traveled (VMT), vehicle type and age distribution, fuels
used, weather inputs, other planning assumptions, and the latest
approved motor vehicle emissions model at the time Illinois EPA began
to prepare the SIP submission, which was MOVES3. Total on-road
emissions in both the Chicago and Metro East areas are shown in Table
5.
Table 5--Total On-Road Emissions in the Chicago and Metro East Areas
[Tons/day]
----------------------------------------------------------------------------------------------------------------
Area Pollutant 2017 2023 Difference
----------------------------------------------------------------------------------------------------------------
Chicago.............................. NOX...................... 208.20 150.90 -57.30
VOC...................... 58.20 49.00 -9.20
Metro East........................... NOX...................... 17.44 9.87 -7.57
VOC...................... 6.81 4.79 -2.02
----------------------------------------------------------------------------------------------------------------
Table 6 identifies Illinois' 2023 budgets. The budgets, agreed upon
as part of the interagency consultation process, include the emission
estimates calculated for 2023 with an additional safety margin
allocated to those estimates to accommodate future variations in travel
demand models and VMT forecasts. A State can add a safety margin to a
budget based on the transportation conformity regulation at 40 CFR
93.124(a).
Table 6--Proposed Motor Vehicle Emissions Budgets for the IL Nonattainment Areas
[Tons/day]
----------------------------------------------------------------------------------------------------------------
2023 Estimated Applied safety Motor vehicle
Area Pollutant mobile emissions margin emissions budget
----------------------------------------------------------------------------------------------------------------
Chicago......................... NOX................. 150.9 14.88 165.78
VOC................. 49.0 3.47 52.47
Metro East...................... NOX................. 9.87 4.42 14.29
VOC................. 4.79 1.98 6.77
----------------------------------------------------------------------------------------------------------------
3. Evaluation of the VOC and NO<INF>X</INF> Budgets
The VOC and NO<INF>X</INF> budgets for the Chicago and Metro East
areas were developed as part of an interagency consultation process
which includes Federal, State, and local agencies. The budgets were
clearly identified and precisely quantified. Illinois has demonstrated
that both the Chicago and Metro East areas can meet the 15% RFP
requirement in 2023 with mobile source emissions of 165.78 tpd of
NO<INF>X</INF> and 52.47 tpd of VOC and 14.29 tpd of NO<INF>X</INF> and
6.77 tpd of VOC, respectively, despite partial allocation of the RFP
plan surplus reductions that can be seen in Table 4. The EPA is thus
proposing to approve the 2023 VOC and NO<INF>X</INF> budgets for use in
determining transportation conformity in the Chicago and Metro East
areas under the 2015 ozone NAAQS.
When reviewing submitted SIPs containing budgets, the EPA reviews
the budgets for adequacy. Once the EPA finds the submitted budget is
adequate for transportation conformity purposes, that budget must be
used by State and Federal agencies in determining whether proposed
transportation projects conform to the SIP as required by section
176(c) of the CAA.
EPA's substantive criteria for determining adequacy of a budget are
set out in 40 CFR 93.118(e)(4). The process for determining adequacy is
found in 40 CFR 93.118(f) and consists
[[Page 6574]]
of three basic steps: public notification of a SIP submission, a public
comment period, and issuance of the EPA's adequacy finding. The
regulations that allow the EPA to begin an adequacy review through a
notice of proposed rulemaking in the Federal Register are found in 40
CFR 93.118(f)(2). This proposal notifies the public that the EPA has
received a SIP submission with budgets that the EPA will review for
adequacy and begins the public comment period. Comments must be
submitted to the docket for this proposal by the close of the comment
period on this proposal. The EPA invites the public to comment on the
adequacy of these budgets as well as on its proposed approval of the
budgets and on other actions the EPA is proposing in this action.
E. NNSR Review
1. Background
NNSR is a preconstruction review permit program that applies to new
major stationary sources or major modifications at existing sources
within a nonattainment area and is required under CAA sections
172(c)(5) and 173. NNSR permit program requirements were adopted for
the 2015 ozone NAAQS at 40 CFR 51.1314 as part of the 2015 SIP
Requirements Rule. The minimum SIP requirements for NNSR permitting
programs for the 2015 ozone NAAQS are contained in 40 CFR 51.165. The
SIP for each ozone nonattainment area must contain NNSR provisions
that: (1) set major source thresholds for NO<INF>X</INF> and VOC
pursuant to 40 CFR 51.165(a)(1)(iv)(A)(1)(i) through (iv) and (2); (2)
classify physical changes as a major source if the change would
constitute a major source by itself pursuant to 40 CFR
51.165(a)(1)(iv)(A)(3); (3) consider any significant net emissions
increase of NO<INF>X</INF> as a significant net emissions increase for
ozone pursuant to 40 CFR 51.165(a)(1)(v)(E); (4) consider any increase
of VOC emissions in Extreme ozone nonattainment areas as a significant
net emissions increase and a major modification for ozone pursuant to
40 CFR 51.165(a)(1)(v)(F); (5) set significant emissions rates for VOC
and NO<INF>X</INF> as ozone precursors pursuant to 40 CFR
51.165(a)(1)(x)(A) through (C) and (E); (6) contain provisions for
emissions reductions credits pursuant to 40 CFR 51.165(a)(3)(ii)(C)(1)
through (2); (7) provide that the requirements applicable to VOC also
apply to NO<INF>X</INF> pursuant to 40 CFR 51.165(a)(8); (8) set offset
ratios for VOC and NO<INF>X</INF> pursuant to 40 CFR 51.165(a)(9)(ii)
through (iv); and (9) require public participation procedures compliant
with 40 CFR 51.165(i).
2. Illinois' NNSR Certification
Illinois affirms that the existing NNSR for new major stationary
sources or major modifications located in areas that the EPA has
designated as nonattainment for a particular criteria pollutant are
sufficient to meet Moderate requirements. Illinois administers this
program through 35 Ill. Adm. Code Part 203, Major Stationary Sources
Construction and Modification. Illinois also implements a minor NSR
permit program through 35 Ill. Adm. Code Part 204, Prevention of
Significant Deterioration (PSD). New major stationary sources or major
modifications subject to NNSR are required to obtain emission offsets
for volatile organic material or nitrogen oxides at ratio of 1.15 to 1
in areas classified as Moderate nonattainment for ozone. The
requirements of the NNSR program were most recently submitted to the
EPA as a SIP revision for the 2008 ozone NAAQS on May 24, 2018, and
approved on October 9, 2018 (83 FR 50551).
Illinois' PSD program set forth at 35 Ill. Adm. Code 204, was
approved by the EPA into Illinois' SIP on September 9, 2021 (86 FR
50459) and became effective October 12, 2021. These program
requirements along with the NNSR program ensure that the initial
construction of new major stationary sources and major modifications of
stationary sources do not cause or contribute to a violation of the
2015 ozone NAAQS.
3. Evaluation of Illinois' NNSR Certification
EPA has reviewed Illinois' approved NNSR rules and is proposing to
approve Illinois' certification submittal because we find that the
current SIP-approved NNSR program satisfies all the NNSR program
requirements currently applicable to the moderate areas for the 2015
ozone NAAQS.
V. What action is the EPA taking?
EPA is proposing to approve portions of Illinois' attainment plan
SIP revision request, dated December 18, 2024, pursuant to section 110
and part D of CAA. The Illinois attainment plan submission satisfies
the base year emissions inventory, the RFP demonstration including 2023
budgets, I/M certification, and NNSR requirements of the CAA for the
Chicago and Metro East nonattainment areas for the 2015 ozone NAAQS.
The EPA is also initiating the adequacy process of the 2023 budgets for
the Chicago and Metro East St. Louis Moderate ozone nonattainment RFP
demonstration included in this SIP submission.
VI. Statutory and Executive Order Reviews
Under the CAA, the Administrator is required to approve a SIP
submission that complies with the provisions of the CAA 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 CAA. Accordingly, this
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 action:
<bullet> Is not a significant regulatory action subject to review
by the Office of Management and Budget under Executive Order 12866 (58
FR 51735, October 4, 1993);
<bullet> Is not subject to Executive Order 14192 (90 FR 9065,
February 6, 2025) because SIP actions are exempt from review under
Executive Order 12866;
<bullet> Does not impose an information collection burden under the
provisions of the Paperwork Reduction Act (44 U.S.C. 3501 et seq.);
<bullet> 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.);
<bullet> 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);
<bullet> Does not have federalism implications as specified in
Executive Order 13132 (64 FR 43255, August 10, 1999);
<bullet> Is not subject to Executive Order 13045 (62 FR 19885,
April 23, 1997) because it approves a State program;
<bullet> Is not a significant regulatory action subject to
Executive Order 13211 (66 FR 28355, May 22, 2001); and
<bullet> 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 CAA.
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. In those areas of
Indian country, the rulemaking does not have Tribal implications and
will not impose substantial direct costs on Tribal governments or
preempt Tribal law as
[[Page 6575]]
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, Nitrogen dioxide, Ozone,
Reporting and recordkeeping requirements, Volatile organic compounds.
Dated: February 3, 2026.
Anne Vogel,
Regional Administrator, Region 5.
[FR Doc. 2026-02842 Filed 2-11-26; 8:45 am]
BILLING CODE 6560-50-P
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This is legal information, not legal advice. Laws vary by jurisdiction and change frequently. Always verify current law with official sources and consult a licensed attorney in your jurisdiction for advice on your specific situation.