Document ID: EPA-R04-OAR-2022-0982-0007
Agency: epa
Document Type: Proposed Rule
Title: Air Quality State Implementation Plans; Approvals and Promulgations: Kentucky; Redesignation of the Northern Kentucky Portion of the Cincinnati, OH-KY 2015 8-Hour Ozone Nonattainment Area to Attainment
Posted Date: 2023-07-28T04:00Z

[Federal Register Volume 88, Number 144 (Friday, July 28, 2023)]
[Proposed Rules]
[Pages 48772-48784]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2023-16223]

[[Page 48772]]

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Parts 52 and 81

[EPA-R04-OAR-2022-0982; FRL-11119-01-R4]

Air Plan Approval and Air Quality Designation; KY; Redesignation 
of the Northern Kentucky Portion of the Cincinnati, OH-KY 2015 8-Hour 
Ozone Nonattainment Area to Attainment

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.

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SUMMARY: On September 21, 2022, the Commonwealth of Kentucky, through 
the Kentucky Energy and Environment Cabinet (Cabinet), Division of Air 
Quality (DAQ), submitted a request for the Environmental Protection 
Agency (EPA) to redesignate the Northern Kentucky portion (hereinafter 
referred to as the ``Northern Kentucky Area'' or ``Area'') of the 
Cincinnati, Ohio- Kentucky, 2015 8-hour ozone nonattainment area 
(hereinafter referred to as the ``Cincinnati OH-KY Area'') to 
attainment for the 2015 8-hour ozone National Ambient Air Quality 
Standards (NAAQS or standards) and to approve a State Implementation 
Plan (SIP) revision containing a maintenance plan for the Area. The 
Cabinet submitted this request and SIP revision through a letter dated 
September 20, 2022, and supplemented it on November 22, 2022. EPA is 
proposing to approve the Commonwealth's plan for maintaining attainment 
of the 2015 8-hour ozone standard in the Northern Kentucky Area, 
including the motor vehicle emission budgets (MVEBs) for nitrogen 
oxides (NOX) and volatile organic compounds (VOCs) for the 
years of 2026 and 2035 for the Area, to incorporate the maintenance 
plan into the SIP, and to redesignate the Area to attainment for the 
2015 8-hour ozone NAAQS. EPA previously approved the redesignation 
request and maintenance plan for the Ohio portion of the Cincinnati, 
OH-KY Area. EPA is also notifying the public of the status of EPA's 
adequacy determination for the MVEBs for the Area.

DATES: Comments must be received on or before August 28, 2023.

ADDRESSES: Submit your comments, identified by Docket ID No. EPA-R04-
OAR-2022-0982 at https://www.regulations.gov. Follow the online 
instructions for submitting comments. Once submitted, comments cannot 
be edited or removed from Regulations.gov. 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. 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, 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.

FOR FURTHER INFORMATION CONTACT: Evan Adams, Air Regulatory Management 
Section, Air Planning and Implementation Branch, Air and Radiation 
Division, U.S. Environmental Protection Agency, Region 4, 61 Forsyth 
Street SW, Atlanta, Georgia 30303-8960. The telephone number is (404) 
562-9009. Mr. Adams can also be reached via electronic mail at 
[email protected].

SUPPLEMENTARY INFORMATION: 

Table of Contents

I. Summary of EPA's Proposed Action
II. Background
III. Criteria for Redesignation
IV. Kentucky's SIP Submittal
V. EPA's Analysis of Kentucky's SIP Submittal
VI. EPA's Analysis of Kentucky's Proposed NOX and VOC 
MVEBs
VII. EPA's Adequacy Determination for the Proposed NOX 
and VOC MVEBs
VIII. Effect of EPA's Proposed Actions
IX. Proposed Actions
X. Statutory and Executive Order Reviews

I. Summary of EPA's Proposed Action

    EPA is proposing to take the following separate but related actions 
addressing the September 20, 2022, submittal, as supplemented on 
November 22, 2022: \1\ (1) to approve Kentucky's plan for maintaining 
the 2015 ozone NAAQS (maintenance plan), including the associated 
MVEBs, for the Northern Kentucky Area and incorporate the plan into the 
SIP, and (2) to redesignate the Northern Kentucky Area to attainment 
for the 2015 8-hour ozone NAAQS. EPA is also notifying the public of 
the status of EPA's adequacy determination for the MVEBs for the 
Northern Kentucky Area. The Northern Kentucky Area is composed of 
portions of Boone, Campbell, and Kenton Counties in Kentucky. The 
Cincinnati, OH-KY Area is composed of the Northern Kentucky Area and 
the counties of Butler, Clermont, Hamilton, and Warren in Ohio. These 
proposed actions are summarized below and described in greater detail 
through this notice of proposed rulemaking.
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    \1\ EPA received the September 21, 2022, submission under a 
cover letter dated September 20, 2022. For clarity, throughout this 
notice, EPA will refer to the September 21, 2022, submission by its 
cover letter date of September 20, 2022.
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    EPA is proposing to approve Kentucky's maintenance plan for its 
portion of the Cincinnati, OH-KY Area as meeting the requirements of 
section 175A (such approval being one of the Clean Air Act (CAA or Act) 
criteria for redesignation to attainment status) and incorporate it 
into the SIP. The maintenance plan is designed to keep the Cincinnati, 
OH-KY Area in attainment of the 2015 8-hour ozone NAAQS through 2035. 
The maintenance plan includes 2026 and 2035 MVEBs for NOX 
and VOC for the Northern Kentucky Area for transportation conformity 
purposes. EPA is proposing to approve these MVEBs and incorporate them 
into the SIP.
    EPA also proposes to determine that the Northern Kentucky Area has 
met the requirements for redesignation under section 107(d)(3)(E) of 
the CAA. Accordingly, EPA is proposing to approve a request to change 
the legal designation of the portions of Boone, Campbell, and Kenton 
Counties in Kentucky's portion of the Cincinnati, OH-KY Area, as found 
at 40 CFR 81.318, from nonattainment to attainment for the 2015 8-hour 
ozone NAAQS.
    EPA is also notifying the public of the status of EPA's adequacy 
process for the MVEBs for the Northern Kentucky Area. The Adequacy 
comment period began on September 28, 2022, with EPA's posting of the 
availability of Kentucky's submission on EPA's Adequacy website 
(https://www.epa.gov/state-and-local-transportation/state-implementation-plans-sip-submissions-currently-under-epa). The Adequacy 
comment period for these MVEBs closed on October 28, 2022. No comments, 
adverse or otherwise, were received during the Adequacy comment period. 
Please see section VII of this notice of proposed rulemaking for 
further explanation of this process and for more details on MVEBs.
    In summary, this notice of proposed rulemaking is in response to 
Kentucky's September 20, 2022, redesignation request and associated SIP 
submission that addresses the specific issues summarized above and the 
necessary

[[Page 48773]]

elements described in section 107(d)(3)(E) of the CAA for redesignation 
of the Kentucky portion of the Cincinnati, OH-KY Area to attainment for 
the 2015 8-hour ozone NAAQS and the associated MVEBs.

II. Background

    On October 1, 2015, EPA revised both the primary and secondary 
NAAQS for ozone to a level of 0.070 parts per million (ppm) to provide 
increased protection of public health and the environment. See 80 FR 
65292 (October 26, 2015). The 2015 ozone NAAQS retains the same general 
form and averaging time as the 0.075 ppm NAAQS set in 2008 but is set 
at a more protective level. Under EPA's regulations at 40 CFR part 50, 
the 2015 8-hour ozone NAAQS is attained when the 3-year average of the 
annual fourth-highest daily maximum 8-hour average ambient air quality 
ozone concentrations is less than or equal to 0.070 ppm. See Appendix U 
of 40 CFR part 50. This 3-year average is referred to as the design 
value.
    Upon promulgation of a new or revised ozone NAAQS, section 107(d) 
of the CAA requires EPA to designate as nonattainment any area that is 
violating the NAAQS (or that contributes to ambient air quality in a 
nearby area that is violating the NAAQS). As part of the designations 
process for the 2015 8-hour ozone NAAQS, the Cincinnati, OH-KY Area was 
designated as a ``Marginal'' ozone nonattainment area, effective August 
3, 2018. See 83 FR 25776 (June 4, 2018). Areas that were designated as 
Marginal ozone nonattainment areas were required to attain the 2015 8-
hour ozone NAAQS no later than August 3, 2021, based on 2018, 2019, and 
2020 monitoring data. See 40 CFR 51.1303. EPA reclassified the Northern 
Kentucky Area to Moderate on October 7, 2022, after failing to attain 
by the attainment date.\2\ See 87 FR 60897 (October 7, 2022) and 40 CFR 
81.318. The October 7, 2022, action requires Moderate areas to attain 
the 2015 8-hour ozone NAAQS as expeditiously as practicable, but no 
later than August 3, 2024, six years after the effective date of the 
initial nonattainment designations. See 40 CFR 51.1303.
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    \2\ EPA proposed to reclassify the Cincinnati, OH-KY Area as a 
Moderate nonattainment area on April 13, 2022. However, prior to 
finalizing the reclassification, EPA redesignated the Ohio portion 
of the Cincinnati OH-KY Area to attainment for the 2015 8-hour ozone 
NAAQS. See 87 FR 35104 (June 9, 2022). EPA finalized the 
reclassification of the Kentucky portion of the Cincinnati OH-KY 
Area on October 7, 2022 (87 FR 60897).
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III. Criteria for Redesignation

    The CAA provides the requirements for redesignating a nonattainment 
area to attainment. Specifically, section 107(d)(3)(E) of the CAA 
allows for redesignation providing that: (1) the EPA Administrator 
determines that the area has attained the applicable NAAQS; (2) the 
Administrator has fully approved the applicable implementation plan for 
the area under section 110(k); (3) the Administrator determines that 
the improvement in air quality is due to permanent and enforceable 
reductions in emissions resulting from implementation of the applicable 
SIP and applicable Federal air pollutant control regulations and other 
permanent and enforceable reductions; (4) the Administrator has fully 
approved a maintenance plan for the area as meeting the requirements of 
section 175A; and (5) the State containing such area has met all 
requirements applicable to the area for purposes of redesignation under 
Section 110 and part D of the CAA.
    EPA provided guidance on redesignations in the General Preamble for 
the Implementation of title I of the CAA Amendments of 1990 on April 
16, 1992 (57 FR 13498) and supplemented that guidance on April 28, 1992 
(57 FR 18070). EPA has provided further guidance on processing 
redesignation requests in the following documents:

    1. ``Ozone and Carbon Monoxide Design Value Calculations,'' 
Memorandum from Bill Laxton, Director, Technical Support Division, 
June 18, 1990;
    2. ``Maintenance Plans for Redesignation of Ozone and Carbon 
Monoxide Nonattainment Areas,'' Memorandum from G. T. Helms, Chief, 
Ozone/Carbon Monoxide Programs Branch, April 30, 1992;
    3. ``Contingency Measures for Ozone and Carbon Monoxide (CO) 
Redesignations,'' Memorandum from G. T. Helms, Chief, Ozone/Carbon 
Monoxide Programs Branch, June 1, 1992;
    4. ``Procedures for Processing Requests to Redesignate Areas to 
Attainment,'' Memorandum from John Calcagni, Director, Air Quality 
Management Division, September 4, 1992 (hereinafter referred to as 
the ``Calcagni Memorandum'');
    5. ``State Implementation Plan (SIP) Actions Submitted in 
Response to Clean Air Act (CAA) Deadlines,'' Memorandum from John 
Calcagni, Director, Air Quality Management Division, October 28, 
1992;
    6. ``Technical Support Documents (TSDs) for Redesignation of 
Ozone and Carbon Monoxide (CO) Nonattainment Areas,'' Memorandum 
from G. T. Helms, Chief, Ozone/Carbon Monoxide Programs Branch, 
August 17, 1993;
    7. ``State Implementation Plan (SIP) Requirements for Areas 
Submitting Requests for Redesignation to Attainment of the Ozone and 
Carbon Monoxide (CO) National Ambient Air Quality Standards (NAAQS) 
On or After November 15, 1992,'' Memorandum from Michael H. Shapiro, 
Acting Assistant Administrator for Air and Radiation, September 17, 
1993 (hereinafter referred to as the ``Shapiro Memorandum'');
    8. ``Use of Actual Emissions in Maintenance Demonstrations for 
Ozone and CO Nonattainment Areas,'' Memorandum from D. Kent Berry, 
Acting Director, Air Quality Management Division, November 30, 1993;
    9. ``Part D New Source Review (Part D NSR) Requirements for 
Areas Requesting Redesignation to Attainment,'' Memorandum from Mary 
D. Nichols, Assistant Administrator for Air and Radiation, October 
14, 1994 (hereinafter referred to as the ``Nichols Memorandum''); 
and
    10. ``Reasonable Further Progress, Attainment Demonstration, and 
Related Requirements for Ozone Nonattainment Areas Meeting the Ozone 
National Ambient Air Quality Standard,'' Memorandum from John S. 
Seitz, Director, Office of Air Quality Planning and Standards, May 
10, 1995.

IV. Kentucky's SIP Submittal

    On September 20, 2022, and supplemented on November 22, 2022, 
Kentucky requested that EPA redesignate the Northern Kentucky Area to 
attainment for the 2015 8-hour ozone NAAQS and approve the associated 
SIP revision submitted on the same date containing a maintenance plan 
for the Area. EPA's evaluation indicates that the Northern Kentucky 
Area meets the requirements for redesignation as set forth in CAA 
section 107(d)(3)(E), including the maintenance plan requirements under 
CAA section 175A and associated MVEBs. As a result of these proposed 
findings, EPA is proposing to take the actions summarized in Section I 
of this notice. EPA's analysis and rationale for this proposal is 
provided below.

V. EPA's Analysis of Kentucky's SIP Submittal

    As stated above, in accordance with the CAA, EPA proposes to 
approve the 2015 8-hour ozone NAAQS maintenance plan, including the 
associated MVEBs, and incorporate it into the Kentucky SIP, and 
redesignate the Northern Kentucky Area to attainment for the 2015 8-
hour ozone NAAQS. The five redesignation criteria provided under CAA 
section 107(d)(3)(E) are discussed in greater detail for the Area in 
the following paragraphs of this section.

Criterion (1)--The Cincinnati, OH-KY Area Has Attained the 2015 8-Hour 
Ozone NAAQS

    For redesignating a nonattainment area to attainment, the CAA 
requires EPA to determine that the area has attained the applicable 
NAAQS. See

[[Page 48774]]

CAA section 107(d)(3)(E)(i). For ozone, an area may be considered to be 
attaining the 2015 8-hour ozone NAAQS if it meets the 2015 8-hour ozone 
NAAQS, as determined in accordance with 40 CFR 50.19 and Appendix U of 
part 50, based on three complete, consecutive calendar years of 
quality-assured air quality monitoring data. To attain the 2015 8-hour 
ozone NAAQS, the 3-year average of the annual fourth highest daily 
maximum 8-hour average ozone concentrations measured at each monitor 
within an area must not exceed 0.070 ppm. Based on the data handling 
and reporting convention described in 40 CFR part 50, Appendix U, the 
2015 8-hour ozone NAAQS are attained if the design value is 0.070 ppm 
or below. The data must be collected and quality-assured in accordance 
with 40 CFR part 58 and recorded in EPA's Air Quality System (AQS). The 
monitors generally should have remained at the same location for the 
duration of the monitoring period required for demonstrating 
attainment.
    EPA reviewed complete, quality-assured, and certified ozone 
monitoring data from monitoring stations in the Cincinnati, OH-KY Area 
for the 2015 8-hour ozone NAAQS for 2019 through 2021 and has 
determined that the design values for each monitor in the Area are 
equal to or less than the standard of 0.070 ppm for that time period. 
Based on this air quality monitoring data, EPA is proposing to 
determine that the Cincinnati, OH-KY Area has attained the 2015 8-hour 
ozone NAAQS. The fourth-highest 8-hour ozone values at each monitor for 
2019 through 2021 and the 3-year averages of these values (i.e., design 
values), are summarized in Table 1, below.

                     Table 1--2019-2021 Ozone Concentrations for the Cincinnati, OH-KY Area
                                                    [ppm] \3\
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                                                    Annual 4th-highest daily maximum 8-hr ozone    Design value
                                                                   concentration                 ---------------
         AQS site code          County and state ------------------------------------------------
                                                       2019            2020            2021          2019-2021
----------------------------------------------------------------------------------------------------------------
21-015-0003...................  Boone, KY.......           0.062           0.062           0.061           0.061
21-037-3002...................  Campbell, KY....           0.062           0.063           0.064           0.063
39-017-0018...................  Butler, OH......           0.067           0.070           0.064           0.067
39-017-0023...................  Butler, OH......           0.067           0.067           0.066           0.066
39-017-9991...................  Butler, OH......           0.065           0.064           0.063           0.064
39-025-0022...................  Clermont, OH....           0.071           0.064           0.065           0.066
39-061-0006...................  Hamilton, OH....           0.072           0.070           0.070           0.070
39-061-0010...................  Hamilton, OH....           0.067           0.070           0.064           0.067
39-061-0040...................  Hamilton, OH....           0.071           0.068           0.069           0.069
39-165-0007...................  Warren, OH......           0.070           0.071           0.069           0.070
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    The highest 3-year design value for 2019-2021 for the Cincinnati, 
OH-KY Area is 0.070 ppm at the Hamilton County, Ohio site (39-061-0006) 
and at the Warren County, Ohio site (39-165-0007),\4\ which meets the 
NAAQS.
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    \3\ Final air quality design values for all criteria pollutants, 
including ozone, are available at https://www.epa.gov/aqs.
    \4\ The design value for an area is the highest 3-year average 
of the annual fourth-highest daily maximum 8-hour concentration 
recorded at any monitor in the area.
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    EPA will not take final action to approve the redesignation of the 
Kentucky portion of the Cincinnati, OH-KY Area if the 3-year design 
value exceeds the NAAQS prior to EPA finalizing the redesignation. 
Preliminary 2022 ozone monitoring data currently indicates attaining 
2022 design values for the Cincinnati, OH-KY Area. As discussed in more 
detail below, Kentucky has committed to continue monitoring in this 
Area in accordance with 40 CFR part 58.

Criterion (2)--Kentucky Has a Fully Approved SIP Under Section 110(k) 
for the Northern Kentucky Area; and Criterion (5)--Kentucky Has Met All 
Applicable Requirements Under Section 110 and Part D of Title I of the 
CAA

    For redesignating a nonattainment area to attainment, the CAA 
requires EPA to determine that the State has met all applicable 
requirements under section 110 and part D of title I of the CAA, see 
CAA section 107(d)(3)(E)(v) and that the State has a fully approved SIP 
under section 110(k) for the area, see CAA section 107(d)(3)(E)(ii). 
EPA proposes to find that Kentucky has met all applicable SIP 
requirements for the Northern Kentucky Area under section 110 of the 
CAA (general SIP requirements) for purposes of redesignation. 
Additionally, EPA proposes to find that Kentucky has met all applicable 
SIP requirements for purposes of redesignation under part D of title I 
of the CAA in accordance with section 107(d)(3)(E)(v), and proposes to 
determine that the SIP is fully approved with respect to all 
requirements applicable for purposes of redesignation in accordance 
with section 107(d)(3)(E)(ii). In making these proposed determinations, 
EPA ascertained which requirements are applicable to the Area and, if 
applicable, that they are fully approved under section 110(k). SIPs 
must be fully approved only with respect to requirements that were due 
prior to submittal of the complete redesignation request.
a. The Northern Kentucky Area Has Met All Applicable Requirements Under 
Section 110 and Part D of the CAA
    General SIP requirements. General SIP elements and requirements are 
delineated in section 110(a)(2) of title I, part A of the CAA. These 
requirements include, but are not limited to, the following: submittal 
of a SIP that has been adopted by the State after reasonable public 
notice and hearing; provisions for establishment and operation of 
appropriate procedures needed to monitor ambient air quality; 
implementation of a source permit program; provisions for the 
implementation of part C requirements (Prevention of Significant 
Deterioration (PSD)) and provisions for the implementation of part D 
requirements (NSR permit programs); provisions for air pollution 
modeling; and provisions for public and local agency participation in 
planning and emission control rule development.

[[Page 48775]]

    Section 110(a)(2)(D)(i)(I) of the Act, referred to as the ``good 
neighbor provision'' or the ``interstate transport provision,'' 
requires that SIPs contain measures to prevent sources in a State from 
significantly contributing to air quality problems in another State. To 
implement this provision, EPA has required certain States to establish 
programs to address the interstate transport of air pollutants. The 
section 110(a)(2)(D)(i)(I) requirements for a State are not linked with 
a particular nonattainment area's designation and classification in 
that State. EPA believes that the requirements linked with a particular 
nonattainment area's designation and classification are the relevant 
measures to evaluate in reviewing a redesignation request. The 
transport SIP submittal requirements, where applicable, continue to 
apply to a State regardless of the designation of any one particular 
area in the State. Thus, EPA does not believe that the CAA's interstate 
transport requirements should be construed to be applicable for 
purposes of redesignation.
    In addition, EPA believes other section 110 elements that are 
neither connected with nonattainment plan submissions nor linked with 
an area's attainment status are not applicable requirements for purpose 
of redesignation. The area will still be subject to these requirements 
after the area is redesignated. The section 110 and part D requirements 
which are linked with a particular area's designation and 
classification are the relevant measures to evaluate in reviewing a 
redesignation request. This approach is consistent with EPA's existing 
policy on applicability (i.e., for redesignations) of conformity and 
oxygenated fuels requirements, as well as with section 184 ozone 
transport requirements. See 61 FR 53174 (October 10, 1996) and 62 FR 
24826 (May 7, 1997) (Reading, Pennsylvania, proposed and final 
rulemakings); 61 FR 20458 (May 7, 1996) (Cleveland-Akron-Loraine, Ohio, 
final rulemaking); and 60 FR 62748, (December 7, 1995) (Tampa, Florida, 
final rulemaking)). See also 65 FR 37890 (June 19, 2000) (discussion on 
this issue in Cincinnati, Ohio, redesignation) and 66 FR 50399 (October 
19, 2001) (Pittsburgh, Pennsylvania, redesignation).
    Title I, part D, applicable SIP requirements. Section 172(c) of the 
CAA sets forth the basic requirements of attainment plans for 
nonattainment areas that are required to submit them pursuant to 
section 172(b). Subpart 2 of part D, which includes section 182 of the 
CAA, establishes specific requirements for ozone nonattainment areas 
depending on the area's nonattainment classification. As provided in 
subpart 2, a Marginal ozone nonattainment area must submit an emissions 
inventory that complies with section 172(c)(3), but the specific 
requirements of section 182(a) apply in lieu of the demonstration of 
attainment (and contingency measures) required by section 172(c). See 
42 U.S.C. 7511a(a). A Moderate area must meet the Marginal area 
requirements of section 182(a) and additional requirements specific to 
Moderate (and higher) areas under section 182(b), as well as the 
general requirements of 172(c). A thorough discussion of the 
requirements contained in sections 172(c) and 182 can be found in the 
General Preamble for Implementation of Title I. See 57 FR 13498 (April 
16, 1992).
    Under its longstanding interpretation of the CAA, EPA has 
interpreted section 107(d)(3)(E) to mean, as a threshold matter, that 
the part D provisions which are ``applicable'' and which must be 
approved in order for EPA to redesignate an area include only those 
which came due prior to a State's submittal of a complete redesignation 
request. See Calcagni Memorandum. See also Shapiro Memorandum; 60 FR 
12459, 12465-66 (March 7, 1995) (Final Redesignation of Detroit-Ann 
Arbor, Michigan,); 68 FR 25418, 25424-27 (May 12, 2003) (Final 
Redesignation of St. Louis, Missouri); and Sierra Club v. EPA, 375 F. 
3d 537, 541 (7th Cir. 2004) (upholding EPA's redesignation rulemaking 
applying this interpretation and expressly rejecting Sierra Club's view 
that the meaning of ``applicable'' under the statute is ``whatever 
should have been in the plan at the time of attainment'' rather than 
``whatever actually was in the plan and already implemented or due at 
the time of attainment'').\5\ For the Northern Kentucky Area, no 
section 182(b) Part D Moderate nonattainment area requirements for the 
2015 8-hour ozone standard were due at the time that Kentucky submitted 
its redesignation request on September 20, 2022; therefore these 
requirements are not applicable for the purposes of redesignation. See 
Section II, above (discussing the reclassification of the Northern 
Kentucky Area to Moderate on October 7, 2022). In addition, as 
discussed below, several of the Part D requirements under 182(a) are 
otherwise not applicable for the purposes of redesignation and several 
of the requirements have already been satisfied by the Commonwealth.
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    \5\ Applicable requirements of the CAA that become due after the 
area's submittal of a complete redesignation request remain 
applicable until a redesignation is approved but are not required as 
a prerequisite to redesignation. See Calcagni Memorandum; CAA 
section 175A(c).
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    Section 182(a) Requirements. Section 182(a)(1) requires States to 
submit a comprehensive, accurate, and current inventory of actual 
emissions from sources of VOC and NOX emitted within the 
boundaries of the ozone nonattainment area. This required submission 
was due by August 3, 2020, for the Northern Kentucky Area. See 40 CFR 
51.1315(a). Kentucky provided an emissions inventory for the Area to 
EPA in a December 22, 2021, SIP submission, and EPA approved the 
emissions inventory in an action published on September 30, 2022. See 
87 FR 59320.
    Under section 182(a)(2)(A), states with ozone nonattainment areas 
that were designated prior to the enactment of the 1990 CAA amendments 
were required to submit, within six months of classification, all rules 
and corrections to existing VOC reasonably available control technology 
(RACT) rules that were required under section 172(b)(3) of the CAA (and 
related guidance) prior to the 1990 CAA amendments. The Area is not 
subject to the section 182(a)(2) RACT ``fix up'' requirement for the 
2015 ozone NAAQS because it was designated as nonattainment for this 
standard after the enactment of the 1990 CAA amendments. Furthermore, 
the Commonwealth complied with this requirement under the 1-hour ozone 
NAAQS for the Northern Kentucky portion of the Cincinnati, OH-KY Area. 
See 59 FR 32343 (June 23, 1994).
    Section 182(a)(2)(B) requires each State with a Marginal or higher 
ozone nonattainment area classification that implemented, or was 
required to implement, a vehicle inspection and maintenance (I/M) 
program prior to the 1990 CAA amendments to submit a SIP revision 
providing for an I/M program no less stringent than that required prior 
to the 1990 amendments or already in the SIP at the time of the 
amendments, whichever is more stringent. The Northern Kentucky Area is 
not subject to the section 182(a)(2)(B) requirement because the Area 
was designated as nonattainment for the 2015 8-hour ozone standard 
after the enactment of the 1990 CAA amendments.
    Regarding the permitting and offset requirements of section 
182(a)(2)(C) and section 182(a)(4), Kentucky currently has a fully 
approved part D NSR program in place. However, EPA has determined that 
areas being redesignated need not comply with the requirement that a 
NSR program be approved prior to redesignation, provided that the area 
demonstrates maintenance of the NAAQS without

[[Page 48776]]

part D NSR, because PSD requirements will apply after redesignation. A 
more detailed rationale for this view is described in the Nichols 
Memorandum. Kentucky's PSD program will become applicable in the 
Northern Kentucky Area upon redesignation to attainment.
    Section 182(a)(3) requires States to submit periodic inventories 
and emissions statements. Section 182(a)(3)(A) requires States to 
submit a periodic inventory every three years. As discussed below in 
the section of this notice titled Verification of Continued Attainment, 
the Commonwealth will continue to update its emissions inventory at 
least once every three years. Under section 182(a)(3)(B), each State 
with an ozone nonattainment area must submit a SIP revision requiring 
emissions statements to be submitted to the State by certain sources 
within that nonattainment area. Kentucky provided a SIP revision to EPA 
on October 16, 2020, addressing the section 182(a)(3)(B) emissions 
statements requirements for the Northern Kentucky Area, and on April 
26, 2022, EPA published a final rule approving that SIP revision. See 
87 FR 24429 (April 26, 2022).
    Section 182(b) Requirements. Section 182(b) of the CAA, found in 
subpart 2 of Part D, establishes additional requirements for Moderate 
(and higher) ozone nonattainment areas. As noted above, no section 
182(b) Moderate nonattainment area requirements for the 2015 8-hour 
ozone standard, including RACT under section 182(b)(2), were due at the 
time that Kentucky submitted its redesignation request on September 20, 
2022; therefore, these requirements are not applicable for the purposes 
of redesignation.
    Section 176 Conformity Requirements. Section 176(c) of the CAA 
requires States to establish criteria and procedures to ensure that 
federally supported or funded projects conform to the air quality 
planning goals in the applicable SIP. The requirement to determine 
conformity applies to transportation plans, programs, and projects that 
are developed, funded, or approved under title 23 of the United States 
Code (U.S.C.) and the Federal Transit Act (transportation conformity) 
as well as to all other federally supported or funded projects (general 
conformity). State transportation conformity SIP revisions must be 
consistent with Federal conformity regulations relating to 
consultation, enforcement, and enforceability that EPA promulgated 
pursuant to its authority under the CAA.
    EPA interprets the conformity SIP requirements \6\ as not applying 
for the purposes of evaluating a redesignation request under section 
107(d) because State conformity rules are still required after 
redesignation and Federal conformity rules apply where State rules have 
not been approved. See Wall v. EPA, 265 F.3d 426 (6th Cir. 2001) 
(upholding this interpretation); see also 60 FR 62748 (December 7, 
1995) (redesignation of Tampa, Florida).\7\
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    \6\ CAA section 176(c)(4)(E) requires states to submit revisions 
to their SIPs to reflect certain Federal criteria and procedures for 
determining transportation conformity. Transportation conformity 
SIPs are different from the MVEBs that are established in control 
strategy SIPs and maintenance plans.
    \7\ Kentucky has an approved conformity SIP for the Northern 
Kentucky Area. See 75 FR 20780 (April 21, 2010).
---------------------------------------------------------------------------

    Thus, for the reasons discussed above, EPA proposes to find that 
the Northern Kentucky Area has satisfied all applicable requirements 
for purposes of redesignation under section 110 and part D of title I 
of the CAA.
b. The Northern Kentucky Area Has a Fully Approved Applicable SIP Under 
Section 110(k) of the CAA
    EPA has fully approved the applicable Kentucky SIP for the Northern 
Kentucky Area under section 110(k) of the CAA for all requirements 
applicable for purpose of redesignation. EPA may rely on prior SIP 
approvals in approving a redesignation request, see Calcagni Memorandum 
at p. 3; Southwestern Pennsylvania Growth Alliance v. Browner, 144 F.3d 
984, 989-90 (6th Cir. 1998); and Wall v. EPA, 265 F.3d 426 (6th Cir. 
2001), plus any additional measures it may approve in conjunction with 
a redesignation action. See 68 FR 25426 (May 12, 2003) (including 
citations therein). Kentucky has adopted and submitted, and EPA has 
fully approved at various times, provisions addressing various SIP 
elements applicable for the ozone NAAQS. See 85 FR 33021 (June 1, 2020) 
and 85 FR 54507 (September 2, 2020). As discussed above, EPA believes 
that the section 110 elements that are neither connected with 
nonattainment plan submissions, nor linked to an area's nonattainment 
status, are not applicable requirements for purposes of redesignation 
and believes that Kentucky has met all part D requirements applicable 
for purpose of this redesignation.

Criterion (3)--The Air Quality Improvement in the Cincinnati, OH-KY 
Area Is Due to Permanent and Enforceable Reductions in Emissions 
Resulting From Implementation of the SIP and Applicable Federal Air 
Pollution Control Regulations and Other Permanent and Enforceable 
Reductions

    For redesignating a nonattainment area to attainment, the CAA 
requires EPA to determine that the air quality improvement in the area 
is due to permanent and enforceable reductions in emissions resulting 
from implementation of the SIP, applicable Federal air pollution 
control regulations, and other permanent and enforceable reductions. 
See CAA section 107(d)(3)(E)(iii). EPA has preliminarily determined 
that Kentucky has demonstrated that the observed air quality 
improvement in the Cincinnati, OH-KY Area is due to permanent and 
enforceable reductions in emissions resulting from Federal measures and 
from State measures adopted into the SIP and is not the result of 
unusually favorable weather conditions or reduced transportation or 
economic slowdown related to the COVID-19 pandemic.\8\
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    \8\ Kentucky provided average temperature data from 2005 to 2021 
and relative humidity data for 2005 to 2020. See section C and 
Appendix C of the State's redesignation request and SIP revision for 
further information. The meteorological data do not suggest 
conditions favorable to reduced ozone levels during 2019 through 
2021. Furthermore, the Commonwealth explains that COVID-19 did not 
influence emissions for a long enough time to affect the Cincinnati 
OH-KY Area's design value. The monitoring data also shows that the 
one-year 4th maximum 8-hour observations did not dramatically change 
between 2019 and 2021. Also, traffic pattern data in the 
Commonwealth show a decrease in traffic volumes that lasted less 
than four months in 2020 (i.e., March 2020-June 2020) and less than 
three months in 2021(i.e., January 2021-March 2021). See Figures 4 
and 5 of the Commonwealth's September 20, 2022, redesignation 
request and SIP revision.
---------------------------------------------------------------------------

    State measures adopted into the SIP and Federal measures enacted in 
recent years have resulted in permanent emission reductions. Kentucky's 
September 20, 2022, submittal identifies SIP-approved State measures, 
some of which implement Federal requirements, that have been 
implemented to date. Those measures specifically regulate cement kilns 
and open burning, as well as a variety of other sources, as explained 
in the following paragraphs.
    Cement Kilns. Kentucky adopted regulation 401 Kentucky 
Administrative Regulation (KAR) 51:170 to regulate NOX 
emissions from cement kilns, setting a limit of 6.6 pounds per ton of 
clinker produced, averaged over a 30-day period. Kentucky has 
regulations in Chapters 59 and 61 of Title 401 of the Kentucky 
Administrative Regulations

[[Page 48777]]

(KAR) which limit NOX and VOC emissions for new and existing 
sources in various source categories.
    Open Burning Bans. EPA first incorporated regulation 401 KAR 63:005 
Open Burning into the Kentucky SIP on July 12, 1982 (47 FR 30059), with 
the latest incorporation on October 17, 2007 (72 FR 58759). This 
regulation prohibits most types of open burning from May through 
September of each year in areas that have been or are currently in 
violation of the ozone NAAQS within Kentucky.
    Other Sources. Kentucky has regulations in Chapters 59 and 61 of 
Title 401 of the KAR which limit NOx and VOC emissions for new and 
existing sources in various source categories.
    Additionally, Federal measures enacted in recent years have also 
resulted in permanent emission reductions in the Northern Kentucky 
Area. The Federal measures that have been implemented include the 
following:
    Tier 2 Emission Standards for Vehicles and Gasoline Sulfur 
Standards. Implementation began in 2004 and as newer, cleaner cars 
enter the national fleet, these standards continue to significantly 
reduce NOX emissions.\9\ These standards require all 
passenger vehicles in any manufacturer's fleet to meet an average 
standard of 0.07 grams of NOX per mile. Additionally, in 
January 2006, the sulfur content of gasoline was required to be on 
average 30 ppm which assists in lowering the NOX emissions. 
EPA expects that these standards will reduce NOX emissions 
from cars by approximately 77 percent, and approximately 86 percent for 
minivans, light trucks, and small SUVs by 2030, translating to nearly 3 
million tons annually by 2030.\10\
---------------------------------------------------------------------------

    \9\ U.S. EPA, Control of Air Pollution from New Motor Vehicles: 
Tier 2 Motor Vehicle Emissions Standards and Gasoline Sulfur Control 
Requirements. See 65 FR 6697 (February 10, 2000).
    \10\ EPA, Regulatory Announcement, EPA420-F-99-051 (December 
1999), available at: https://nepis.epa.gov/Exe/ZyPDF.cgi/P1001Z9W.PDF?Dockey=P1001Z9W.PDF.
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    Tier 3 Motor Vehicle Emission and Fuel Standards. Implementation 
began in 2017 and will continue to phase in through 2025.\11\ These 
standards set new vehicle emissions standards and lower the allowed 
sulfur content of gasoline in order to reduce air pollution from 
passenger cars and trucks. Tailpipe and evaporative emissions will be 
reduced for passenger cars, light-duty trucks, medium-duty passenger 
vehicles, and some heavy-duty vehicles. The Tier 3 vehicle standards 
for light-duty vehicles, light-duty trucks, and medium-duty passenger 
vehicles will be a fleet average standard of 0.03 gram of non-methane 
organic gases (NMOG) + NOX per mile as measured on the 
Federal Test Procedure (FTP), and a fleet average standard 0.05 gram of 
NMOG + NOX per mile as measured on the Supplemental Federal 
Test Procedure (SFTP). The Tier 3 vehicle standards for heavy-duty 
pickup trucks and vans will be 0.178 gram per mile of non-methane 
organic gases (NMOG) + NOX for Class 2b vehicles and 0.247 
gram per mile of NMOG + NOX for Class 3 vehicles, as 
measured on the FTP. This standard required Federal gasoline to meet an 
annual average standard of 10 ppm of sulfur by January 1, 2017. The 
Tier 3 tailpipe standards for light-duty vehicles will reduce the fleet 
average standards for the sum of NMOG and NOX, NMOG + 
NOX, by approximately 80 percent from the current fleet 
average standards, and will reduce the per-vehicle particulate matter 
(PM) standards by 70 percent. The Tier 3 program for heavy-duty 
vehicles will reduce the fleet average standards for NMOG + 
NOX and PM by approximately 60 percent from the current 
fleet average standards. The Tier 3 program is also reducing the 
evaporative VOCs by approximately 50 percent from the current 
standards, and these standards apply to all light-duty and on-road 
gasoline-powered heavy-duty vehicles.
---------------------------------------------------------------------------

    \11\ See 79 FR 23414.
---------------------------------------------------------------------------

    Heavy-Duty Engine and Vehicle Standards and Highway Diesel Fuel 
Sulfur Control Requirements. EPA issued this rule in 2001. See 66 FR 
5002 (January 18, 2001). This rule includes standards limiting the 
sulfur content of diesel fuel, which went into effect in 2004. A second 
phase took effect in 2007, which further reduced the highway diesel 
fuel sulfur content to 15 ppm, leading to additional reductions in 
combustion NOX and VOC emissions. EPA expects that this rule 
will achieve a 95 percent reduction in NOX emissions from 
diesel trucks and buses and will reduce NOX emissions by 2.6 
million tons by 2030 when the heavy-duty vehicle fleet is completely 
replaced with newer heavy-duty vehicles that comply with these emission 
standards.
    National Greenhouse Gas (GHG) Emission Standards for Passenger Cars 
and Light Trucks. In 2010 and 2012, EPA issued rulemakings for Federal 
GHG and fuel economy standards that apply to light-duty cars and trucks 
in model years 2012-2016 (Phase 1) and 2017-2025 (Phase 2). The final 
standards are projected to result in an average industry fleet-wide 
level of 163 grams/mile in carbon dioxide which is equivalent to 54.5 
miles per gallon if achieved exclusively through fuel economy 
improvements. The fuel economy standards result in less fuel being 
consumed and, therefore, slightly less VOC emissions released.
    EPA issued the Safer Affordable Fuel-Efficient (SAFE) Vehicles Rule 
on March 20, 2020, as an update to Phase 2. This new standard sets fuel 
economy and CO2 standards that increase 1.5 percent in 
stringency each year from model years 2021 through 2026 and applies to 
passenger cars and light trucks. On February 8, 2021, the D.C. Circuit 
issued an order granting the Federal Government's motion to stay 
litigation over the SAFE Vehicles Rule (Union of Concerned Scientists 
v. NHTSA, Case No. 19-1230 (D.C. Cir.)).
    On December 30, 2021, EPA published the Revised 2023 and Later 
Model Year Light-Duty Vehicle Greenhouse Gas Emissions Standards 
(Revised 2023 GHG Standards). See 86 FR 74434. The Revised 2023 GHG 
Standards revised, and made more stringent, the GHG standards to be 
more stringent than the SAFE rule standards in each model year from 
2023 through 2026. The action also includes temporary targeted 
flexibilities to address the lead time of the final standards and to 
incentivize the production of vehicles with zero and near-zero 
emissions technology and EPA made technical amendments to clarify and 
streamline regulations. These standards will result in a reduction in 
GHG emissions. They will also result in a net reduction in NOx 
emissions by 2050.
    National Emission Standards for Hazardous Air Pollutants From Coal- 
and Oil-Fired Electric Utility Steam Generating Units and Standards of 
Performance for Fossil-Fuel-Fired Electric Utility, Industrial-
Commercial-Institutional, and Small Industrial-Commercial-Institutional 
Steam Generating Units.\12\ The Mercury and Air Toxics Standard (MATS) 
and the new source performance standard (NSPS) were published in 2012. 
See 77 FR 9304 (February 16, 2012). MATS was promulgated to reduce 
emissions of heavy metals, including mercury (Hg), arsenic (As), 
chromium (Cr), and nickel (Ni); and acid gases, including hydrochloric 
acid (HCl) and hydrofluoric acid (HF) from new and existing coal and 
oil-fired electric utility steam generating units (EGUs). The MATS 
compliance date for new sources

[[Page 48778]]

was April 16, 2012, and April 16, 2015, for existing sources.
---------------------------------------------------------------------------

    \12\ Kentucky's submittal refers to these as Utility Mercury Air 
Toxics Standards (MATS) and New Source Performance Standards (NSPS).
---------------------------------------------------------------------------

    National Emission Standards for Hazardous Air Pollutants (NESHAPs) 
for Major Sources: Industrial, Commercial, and Institutional Boilers 
and Process Heaters; National Emissions Standards for Hazardous Air 
Pollutants for Stationary Reciprocating Internal Combustion 
Engines.\13\ The NESHAP for industrial, commercial, and institutional 
boilers (40 CFR part 63 subpart DDDDD) and the NESHAP for Reciprocating 
Internal Combustion Engines (RICE) (40 CFR part 63 subpart ZZZZ) are 
projected to reduce VOC emissions. The former applies to boiler and 
process heaters located at major sources of hazardous air pollutants 
(HAPs) that burn natural gas, fuel oil, coal, biomass, refinery gas, or 
other gas and had a compliance deadline of January 31, 2016. The latter 
applies to existing, new, or reconstructed stationary RICE located at 
major or area sources of HAPs, excluding stationary RICE being tested 
at a stationary RICE test cell, and has various compliance dates from 
August 16, 2004, to October 19, 2013, depending on the type of source 
and date of construction or reconstruction.
---------------------------------------------------------------------------

    \13\ The Kentucky submittal refers to these as the Boiler and 
Reciprocating Internal Combustion Engine (RICE) National Emissions 
Standards for Hazardous Air Pollutants (NESHAP).
---------------------------------------------------------------------------

    Nonroad Spark-Ignition Engines and Recreational Engines Standards. 
On November 8, 2002 (67 FR 68242), EPA adopted emission standards for 
large spark-ignition engines such as those used in forklifts and 
airport ground service equipment; recreational vehicles such as off-
highway motorcycles, all-terrain vehicles, and snowmobiles; and 
recreational marine diesel engines. These emission standards were 
phased in from model year 2004 through 2012. When fully implemented by 
2030, EPA estimates an overall 75 percent reduction in VOC emissions 
and an 82 percent reduction in NOX emissions. These controls 
reduce ambient concentrations of ozone, carbon monoxide, and fine 
particulate matter.
    Category 3 Marine Diesel Engine Standards. On April 30, 2010 (75 FR 
22896), EPA issued emission standards for marine compression-ignition 
engines at or above 30 liters per cylinder. Tier 2 emission standards 
applied beginning in 2011 and are expected to result in a 15 to 25 
percent reduction in NOx emissions from these engines. Final Tier 3 
emission standards applied beginning in 2016 and are expected to result 
in approximately an 80 percent reduction in NOx from these engines.
    Transportation Rulemakings. In any given location, ozone pollution 
levels are impacted by a combination of background ozone concentration, 
local emissions, and emissions from upwind sources resulting from ozone 
transport. Downwind States' ability to meet health-based air quality 
standards such as the NAAQS is challenged by the transport of ozone 
pollution across State borders. See, e.g., 87 FR 20036 (April 6, 2022). 
EPA acknowledges the historical account in Kentucky's September 20, 
2022, submittal and the historical account of national interstate 
transport rules and associated NOX ozone season trading 
programs \14\ that addressed interstate transport for previous 1979 1-
hour, 1997 8-hour and the 2008 8-hour ozone NAAQS. These programs have 
provided some benefits in the form of NOx ozone season emission 
reductions for certain sources in the Commonwealth and regionally.
---------------------------------------------------------------------------

    \14\ Kentucky's September 21, 2022, redesignation request 
identifies the following control measures for NOX: 
October 27, 1998, NOX SIP Call (63 FR 57356), 2005 Clean 
Air Interstate Rule (CAIR) (70 FR 25162), and 2011 Cross-State Air 
Pollution Rule (CSAPR) (76 FR 48208) and 2016 CSAPR Update (81 FR 
74504). The NOX SIP Call (including the NOX 
Budget Trading Program) and CAIR were established to reduce 
NOX ozone season emissions from EGUs and large non-EGUs 
for the 1-hour 1979 and 8-hour 1997 ozone standards. See 67 FR 17624 
(April 11, 2002), 74 FR 54755 (October 23, 2009) and 72 FR 56623 
(October 4, 2007). The NOX SIP call NOX Budget 
trading program provided NOX emission reduction for EGUs 
and non-EGUs for older ozone NAAQS. Kentucky's redesignation request 
is not relying on this the NOX SIP Call NOX 
budget trading program for the purpose of demonstrating permanent 
and enforceable measures that attribute to the demonstration of 
attainment for the current and more stringent 2015 8-hour ozone 
standard. Kentucky's submission explicitly states that 
NOX reductions achieved as a result of CAIR are not 
reflected in the emissions inventory and projections for the 
Kentucky portion of the Area. Specifically, Kentucky's redesignation 
request is not relying on CAIR to demonstrate attainment of the 2015 
ozone NAAQS for the Northern Kentucky Area. The group of CSAPRs 
addressed the 1997 ozone and PM2.5 standards, 2006 
PM2.5 and 2008 ozone NAAQS. See 76 FR 48208 (August 8, 
2011) and 81 FR 74504 (October 26, 2016). However, the 
NOX ozone season trading programs for these trading 
programs were not adopted into the Kentucky's SIP. EPA notes that 
the CAIR and the NOX SIP Call NOX Budget 
Trading programs are no longer federally enforceable due to 
subsequent NAAQS interstate transport obligations and legal 
challenges (North Carolina v. EPA, 531 F.3d 896 (D.C. Cir. 2008). 
However, the State still has ongoing NOX SIP call 
obligations pursuant to 40 CFR 51.121.
---------------------------------------------------------------------------

    EPA proposes to find that the improvements in air quality in the 
Northern Kentucky Area are due to real, permanent and enforceable 
reductions in NOX and VOC emissions resulting from the 
Federal and SIP-approved State measures discussed above.

Criterion (4)--The Northern Kentucky Area Has a Fully Approved 
Maintenance Plan Pursuant to Section 175A of the CAA

    For redesignating a nonattainment area to attainment, the CAA 
requires EPA to determine that the area has a fully approved 
maintenance plan pursuant to section 175A of the CAA. See CAA section 
107(d)(3)(E)(iv). In conjunction with its request to redesignate the 
Northern Kentucky Area to attainment for the 2015 8-hour ozone NAAQS, 
Kentucky submitted a SIP revision to provide for the maintenance of the 
2015 8-hour ozone NAAQS for at least 10 years after the effective date 
of redesignation to attainment. EPA has made the preliminary 
determination that this maintenance plan meets the requirements for 
approval under section 175A of the CAA.
a. What is required in a maintenance plan?
    Section 175A of the CAA sets forth the elements of a maintenance 
plan for areas seeking redesignation from nonattainment to attainment. 
Pursuant to section 175A, the plan must demonstrate continued 
attainment of the applicable NAAQS for at least 10 years after the 
Administrator approves a redesignation to attainment. Eight years after 
the redesignation, the State must submit a revised maintenance plan 
which demonstrates that attainment will continue to be maintained for 
the remainder of the 20-year period following the initial 10-year 
period. To address the possibility of future NAAQS violations, the 
maintenance plan must contain contingency measures as EPA deems 
necessary to assure prompt correction of any future 2015 8-hour ozone 
violations. The Calcagni Memorandum provides further guidance on the 
content of a maintenance plan, explaining that a maintenance plan 
should address five requirements: the attainment emissions inventory, 
maintenance demonstration, monitoring plan, verification of continued 
attainment, and a contingency plan. As discussed more fully below, EPA 
has preliminarily determined that Kentucky's maintenance plan includes 
all the necessary components and is thus proposing to approve it as a 
revision to the Kentucky SIP.
b. Attainment Emissions Inventory
    As discussed above, the Northern Kentucky Area has an attaining 
design value for the 2015 8-hour ozone NAAQS based on quality-assured 
monitoring data for the 3-year period from 2019-

[[Page 48779]]

2021.\15\ The Northern Kentucky Area's preliminary 2020-2022 design 
value currently indicates that the area will likely continue to attain 
the 2015 ozone NAAQS. Kentucky selected 2019 as the attainment 
emissions inventory year for developing a comprehensive emissions 
inventory for NOX and VOC, from which projected emissions 
could be developed for 2026 and 2035. The attainment inventory 
identifies a level of emissions in the Area that is sufficient to 
attain the 2015 8-hour ozone NAAQS. Kentucky began development of the 
attainment inventory by first generating a baseline emissions inventory 
for the Area. The 2019 attainment year emissions were projected to 2035 
for EGU point sources, non-EGU point sources, area sources, non-road 
mobile sources, and on-road mobile sources. The Commonwealth projected 
summer day emissions inventories using projected rates of growth in 
population, traffic, economic activity, and other parameters. In 
addition to comparing the final year of the plan (2035) to the 2019 
attainment year, Kentucky compared interim years to the attainment year 
to demonstrate that these years are also expected to show continued 
maintenance of the 2015 8-hour ozone standard.
---------------------------------------------------------------------------

    \15\ Final air quality design values for all criteria 
pollutants, including ozone, are available at https://www.epa.gov/air-trends/aqs. These design values are calculated in accordance 
with 40 CFR part 50.
---------------------------------------------------------------------------

    The emissions inventory is composed of four major types of sources: 
Point, non-point, on-road, and non-road mobile. Complete descriptions 
of how the Commonwealth developed these inventories are in Appendices B 
and C of the September 20, 2022, SIP submittal. Kentucky's emissions 
inventory for the Northern Kentucky Area provides 2014 and 2019 
anthropogenic emissions data for NOX and VOC for the 
following general source categories: point (EGUs and non-EGUs), area, 
non-road mobile, on-road mobile. All emissions information provided is 
based on the partial county boundaries, through the applicable census 
tracts, that comprise the Northern Kentucky Area. Table 2, below, 
provides a summary of the 2019 emissions inventory.
---------------------------------------------------------------------------

    \16\ The Commonwealth calculated the tons per summer day by 
selecting July as the representative month. Point source emissions 
were calculated as the ratio of the average July day (obtained from 
the modeling platform) to annual emissions for all point sources. 
The remaining source category emissions were derived from the July 
monthly emissions from the modeling platform and then divided by 31 
to calculate the daily or tons per summer day emission.

                                                 Table 2--2019 Emissions for the Northern Kentucky Area
                                                        [Tons per average summer day (tpsd)] \16\
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                        Point **                Area             Non-road mobile       On-road mobile
                            County *                             ---------------------------------------------------------------------------------------
                                                                     NOX        VOC        NOX        VOC        NOX        VOC        NOX        VOC
--------------------------------------------------------------------------------------------------------------------------------------------------------
Boone...........................................................       5.99       2.75       2.54       7.29       0.74       1.49       4.67       1.34
Campbell........................................................       0.29       0.40       0.92       2.23       0.38       0.52       2.19       0.79
Kenton..........................................................       0.28       0.43       1.53       4.11       0.57       0.74       5.45       1.58
--------------------------------------------------------------------------------------------------------------------------------------------------------
* Nonattainment portion of each county.
** Includes aircraft emissions.

Point Sources

    Point sources are large, stationary, identifiable sources of 
emissions that release pollutants into the atmosphere. The inventory 
contains actual point source emissions data from the years 2014 and 
2019 for facilities located within the nonattainment boundary for the 
Kentucky portion of the Area based on the Kentucky Emissions Inventory 
database. Kentucky obtained this data from Kentucky State emissions 
inventory databases (KYEIS) for EGU and non-EGU stationary sources with 
emissions equal to or exceeding 250 tons per year of VOC or 2,500 tons 
per year of NOX in Boone, Campbell and Kenton Counties in 
Kentucky.

Area Sources

    Area (i.e., non-point) sources are small emission stationary 
sources which, due to their large number, collectively have significant 
emissions (e.g., dry cleaners, service stations). For area and non-road 
sources, the 2014 base year inventory was developed using the 2014v7.1 
(version 2014fd) modeling platform. The Emissions Modeling platform 
2016v2 (versions 2016j, 2023j, 2026j, and 2023fj) was used to project 
the inventories for 2023, 2026, and 2032.. The 2014v7.1 modeling 
platform was selected to represent actual emissions data in the base 
year of 2014. The 2016v2 modeling platform was used since it included 
the best available inventory for the projected years. The 2016v1 
emissions modeling platform is a product from the National Emissions 
Inventory Collaborative, a collaboration between State and regional air 
agencies, EPA, and Federal Land Management agencies, and includes a 
full suite of 2016 emissions and projection year (2023 and 2028) 
inventories, ancillary emission data, and scripts and software for 
preparing the emissions for air quality modeling. The 2016v2 emissions 
modeling platform was developed by EPA as an update to the 2016v1 
platform because new data, model versions, and methods became available 
following the release of 2016v1.\17\ In addition, 2016v2 makes use of a 
new inventory method for solvents, includes minor corrections to the 
wildfire inventory, and corrects for double counting of the airport 
emissions. The commercial marine vessel and rail inventories are 
consistent with the 2016v1 inventories. The 2016v2 platform includes 
emissions for the years 2016, 2023, 2026, and 2032.
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    \17\ The 2016v2 platform incorporates emissions based on MOVES3, 
the 2017 NEI nonpoint inventory, the Western Regional Air 
Partnership oil and gas inventory, and updated inventories for 
Canada and Mexico.
---------------------------------------------------------------------------

    The 2014 base year emissions were derived from 2014 emissions from 
the 2014v7.1 (2014fd) platform, without modification. The 2019 
attainment year emissions were derived by interpolating between the 
2016 and projected 2026 emissions from the 2016v2 (2016fd and 2023fd) 
platform. Kentucky used census tract population data to determine an 
approximate percentage that accounts for sources in the nonattainment 
portion of each county. Since only a portion of each county is 
contained in the Northern Kentucky Area, the emissions from each 
partial county were determined by multiplying the emissions for the 
entire county by the percentage of the county that is in the 
nonattainment area. Emissions from the county portions were then 
projected out to the appropriate future years.

[[Page 48780]]

On-Road Mobile Sources

    On-road mobile sources include vehicles used on roads for 
transportation of passengers or freight. The 2019 on-road emissions 
provided in the Kentucky submittal and all projected year inventories 
were developed using the most recent information from the travel demand 
model (TDM) designed by the Ohio-Kentucky-Indiana Regional Council of 
Governments (OKI) and data obtained from MOVES3 (Motor Vehicle 
Emissions Simulator). The 2019 on-road mobile source (on-road) 
emissions data provided in the Kentucky submittal were developed by the 
Ohio-Kentucky-Indiana Regional Council of Governments (OKI) from 
emission factors produced by EPA's Motor Vehicle Emissions Simulator 
(MOVES3) software program and data extracted from the region's updated 
travel-demand model. OKI is the metropolitan planning organization for 
the Greater Cincinnati area. This updated data for mobile source 
emissions is in Appendix C.

Non-Road Mobile Sources

    Non-road mobile sources include vehicles, engines, and equipment 
used for construction, agriculture, recreation, and other purposes that 
do not use roadways (e.g., lawn mowers, construction equipment, and 
railroad locomotives). The non-road emissions data provided by Kentucky 
in the submittal were derived by interpolating between the 2016 and 
projected 2026 emissions from EPA's 2016v2 emissions platform. Kentucky 
used census tract population data to determine an approximate 
percentage that accounts for sources in the nonattainment portion of 
each county. Since only a portion of each county is contained in the 
Northern Kentucky Area, the emissions from each partial county were 
determined by multiplying the emissions for the entire county by the 
percentage of the county that is in the nonattainment area. Emissions 
from the county portions were then projected out to the appropriate 
future years.
    The 2019 attainment year inventories for all source categories, as 
well as the projected inventories for other years, were developed 
consistent with EPA guidance and are summarized in Tables 3 through 6 
of the following subsection discussing the maintenance demonstration.
c. Maintenance Demonstration
    The redesignation request includes a maintenance plan which 
includes the following features:
    (i) Shows compliance with and maintenance of the 2015 8-hour ozone 
NAAQS by providing information to support the demonstration that 
current and future emissions of NOX and VOC remain at or 
below 2019 emissions levels.
    (ii) Uses 2019 as the attainment year and includes future emissions 
inventory projections for 2026 and 2035. The 2019 emissions were 
obtained from Kentucky databases. The 2026 emissions were derived from 
2026 EPA-projected emissions from the 2016v2 (2026fj) emissions 
modeling platform without modification. The 2035 on-road emissions were 
obtained from MOVES3. The 2035 emissions for area, non-road, and non-
EGUs were derived by extrapolating from the 2016v2 (2032fj) emissions 
modeling platform for 2032 using the TREND function in Microsoft Excel. 
The 2035 projected emissions for EGUs were derived by extrapolating 
from the 2030 EPA-projected emissions from the 2016v2 (2030fj) 
emissions modeling platform using the TREND function in Microsoft 
Excel. If the TREND function resulted in a negative value, the 
emissions were assumed to be the same as 2030. If a 2030 projection was 
missing, the emissions were assumed to be the same as in 2026.
    (iii) Identifies an ``out year'' at least 10 years after the time 
necessary for EPA to review and approve the maintenance plan. Per 40 
CFR part 93, NOX and VOC MVEBs were established for the last 
year (2035) of the maintenance plan. MVEBs were also established for an 
interim year of 2026 (see Section VI, of this preamble).\18\
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    \18\ Kentucky interpolated 2019 emissions using the TREND 
function based on the 2017 NEI emissions and 2023, 2028, and 2032 
projected emissions. Emissions from 2017 as well as projections from 
all future years were chosen to interpolate 2019 by using just the 
two closest years (2017 and 2023).
---------------------------------------------------------------------------

    (iv) Provides actual (2019) and projected emissions inventories, in 
tons per summer day (tpsd), for each county, as well as the total 
emissions for each county in the Kentucky portion of the Cincinnati, 
OH-KY Area. See Tables 3 through 6, below.

                                            Table 3--2026 Projected Emissions for the Northern Kentucky Area
                                                                         [tpsd]
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                        Point **                Area                Non-road               On-road
                            County *                             ---------------------------------------------------------------------------------------
                                                                     NOX        VOC        NOX        VOC        NOX        VOC        NOX        VOC
--------------------------------------------------------------------------------------------------------------------------------------------------------
Boone...........................................................       2.13       1.68       3.22       8.21       0.58       1.28       2.65       1.03
Campbell........................................................       0.28       0.42       0.70       2.22       0.29       0.40       0.94       0.51
Kenton..........................................................       0.29       0.64       1.22       4.21       0.41       0.71       2.44       1.02
--------------------------------------------------------------------------------------------------------------------------------------------------------
* Nonattainment portion of each county.
** Includes aircraft emissions.

                                            Table 4--2035 Projected Emissions for the Northern Kentucky Area
                                                                         [tpsd]
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                        Point **                Area                Non-road               On-road
                            County *                             ---------------------------------------------------------------------------------------
                                                                     NOX        VOC        NOX        VOC        NOX        VOC        NOX        VOC
--------------------------------------------------------------------------------------------------------------------------------------------------------
Boone...........................................................       2.35       1.68       3.85       8.99       0.54       1.25       2.00       0.86
Campbell........................................................       0.28       0.42       0.58       2.22       0.26       0.37       0.57       0.36
Kenton..........................................................       0.30       0.64       1.06       4.28       0.37       0.72       1.64       0.72
--------------------------------------------------------------------------------------------------------------------------------------------------------
* Nonattainment portion of each county.
** Includes aircraft emissions.

[[Page 48781]]

                     Table 5--Total NOX Emissions Inventories for the Northern Kentucky Area
                                                     [tpsd]
----------------------------------------------------------------------------------------------------------------
                            County *                                   2019            2026            2035
----------------------------------------------------------------------------------------------------------------
Boone...........................................................           13.94            8.58            8.74
Campbell........................................................            3.78            2.21            1.69
Kenton..........................................................            7.83            4.36            3.37
                                                                 -----------------------------------------------
    Total.......................................................           25.55           15.15           13.80
----------------------------------------------------------------------------------------------------------------
* Nonattainment portion of each county.

                     Table 6--Total VOC Emissions Inventories for the Northern Kentucky Area
                                                     [tpsd]
----------------------------------------------------------------------------------------------------------------
                            County *                                   2019            2026            2035
----------------------------------------------------------------------------------------------------------------
Boone...........................................................           12.87           12.20           12.78
Campbell........................................................            3.94            3.55            3.37
Kenton..........................................................            6.86            6.58            6.38
                                                                 -----------------------------------------------
    Total.......................................................           23.67           22.33           22.53
----------------------------------------------------------------------------------------------------------------
* Nonattainment portion of each county.

    In situations where local emissions were the primary contributor to 
nonattainment, such as the Northern Kentucky Area, if the future 
projected emissions in the nonattainment area remain at or below the 
baseline emissions in the nonattainment area, then the related ambient 
air quality standard should not be exceeded in the future. Kentucky has 
projected emissions as described previously and determined that 
emissions in the Northern Kentucky Area will remain below those in the 
attainment year inventory for the duration of the maintenance plan.
    As discussed in Section VI, of this preamble, a safety margin is 
the difference between the attainment level of emissions (from all 
sources) and the projected level of emissions (from all sources) in the 
maintenance plan. The attainment level of emissions is the level of 
emissions during one of the years in which the area met the NAAQS. 
Kentucky selected 2019 as the attainment emissions inventory year for 
the Northern Kentucky Area and calculated safety margins for 2026 and 
2035. The Commonwealth has allocated a portion of the safety margin to 
the 2026 and 2035 MVEBs for the Northern Kentucky Area.
    The Commonwealth has decided to allocate a portion of the available 
safety margin to the 2026 and 2035 MVEBs to allow for, among other 
things, unanticipated growth in vehicle miles travelled and changes and 
uncertainty in vehicle mix assumptions that will influence the emission 
estimations. This allocation and the resulting available safety margin 
for the Northern Kentucky Area are discussed further in Section VI, of 
this preamble, along with the MVEBs to be used for transportation 
conformity purposes.
d. Monitoring Network
    There currently are two ozone monitors in the Northern Kentucky 
Area and eight in the Ohio portion of the Cincinnati, OH-KY Area. 
Kentucky will continue to operate an ambient air quality monitoring 
network in the Northern Kentucky Area in compliance with 40 CFR part 58 
and has thus addressed the requirement for the monitoring. EPA approved 
Kentucky's 2022 ambient air monitoring network plan on October 25, 
2022.
e. Verification of Continued Attainment
    Kentucky, through the Cabinet, has the legal authority to enforce 
and implement the maintenance plan for the Area. This includes the 
authority to adopt, implement, and enforce any subsequent emissions 
control contingency measures determined to be necessary to correct 
future ozone attainment problems.
    Additionally, under the Air Emissions Reporting Requirements (AERR) 
(40 CFR part 51, subpart A), every three years the Cabinet is required 
to develop a comprehensive, annual, statewide emissions inventory that 
is due 12 to 18 months after the completion of the inventory year. The 
Cabinet will update the AERR inventory every three years and will use 
the update emissions inventory to track the progress of maintenance of 
the NAAQS. The maintenance plan States that emissions information will 
be compared to the 2019 attainment year and the 2035 projected 
maintenance year inventories to assess emission trends, as necessary, 
and to assure continued compliance with the standard.
f. Contingency Measures in the Maintenance Plan
    Section 175A of the CAA requires that a maintenance plan include 
such contingency measures as EPA deems necessary to assure that the 
State will promptly correct a violation of the NAAQS that occurs after 
redesignation. The maintenance plan should identify the contingency 
measures to be adopted, a schedule and a procedure for adoption and 
implementation, and a time limit for action by the State. A State 
should also identify specific indicators to be used to determine when 
the contingency measures need to be implemented. The maintenance plan 
must include a requirement that a State will implement all measures 
with respect to control of the pollutant that were contained in the SIP 
before redesignation of the area to attainment in accordance with 
section 175A(d).
    In the September 20, 2022, submittal, Kentucky states that, at a 
minimum, contingency measures must include all measures with respect to 
the control of ozone contained in the SIP for the Area before the 
redesignation, that all such measures are in effect for the Area, and 
that it will continue to implement these measures The contingency 
measures in the maintenance plan include a two-tiered triggering 
mechanism to determine when contingency measures are needed and a 
process of developing and implementing appropriate control measures.
    Kentucky's first-tier response is an ``indicator'' response. An 
indicator

[[Page 48782]]

response is triggered if (1) there is an annual fourth high monitored 
value of 0.071 ppm or greater in a single ozone season or (2) periodic 
emission inventory updates reveal excessive or unanticipated growth 
greater than 10 percent in ozone precursor emissions within the 
Cincinnati OH-KY Area. For the indicator response, Kentucky will 
evaluate existing control measures to see if further emission reduction 
measures should be implemented. Kentucky commits to implementing 
necessary controls as expeditiously as possible, but no later than 12 
months from the conclusion of the most recent ozone season (October 
31).
    Kentucky refers to the second-tier response as an ``action level 
response.'' The action level response is triggered if a three-year 
average of the fourth highest monitored value of 0.071 ppm or greater 
(i.e., a violation of the 2015 ozone NAAQS). For an action level 
response, Kentucky commits to determining additional control measures 
needed to assure future attainment of the 2015 ozone NAAQS. This will 
be done in conjunction with the metropolitan planning organization or 
regional council of governments, and appropriate contingency measures 
will be implemented within 24 months of a triggered violation.
    Kentucky commits to adopt, within nine months, one or more of the 
following contingency measures to re-attain the standard in the event 
of a monitored violation; however, it reserves the right to implement 
other contingency measures if new control programs should be developed 
and deemed more advantageous for the Area:
     Implementation of a program to require additional emission 
reductions on stationary sources;
     Restriction of certain roads or lanes to, or construction 
of such roads or lanes for use by, passenger buses or high-occupancy 
vehicles;
     Trip-reduction ordinances;
     Employer-based transportation management plans, including 
incentives;
     Programs to limit or restrict vehicle use in downtown 
areas, or other areas of emission concentration, particularly during 
periods of peak use; and
     Programs for new construction and major reconstructions of 
paths or tracks for use by pedestrians or by non-motorized vehicles 
when economically feasible and in the public interest.
    EPA preliminarily finds that the maintenance plan adequately 
provides the five basic required components of a maintenance plan: the 
attainment emissions inventory, maintenance demonstration, monitoring 
plan, verification of continued attainment, and a contingency plan. 
Therefore, EPA proposes to find that the maintenance plan SIP revision 
submitted by Kentucky for the Northern Kentucky Area meets the 
requirements of section 175A of the CAA and is approvable.

VI. EPA's Analysis of Kentucky's Proposed NOX and VOC MVEBs

    Under section 176(c) of the CAA, new transportation plans, 
programs, and projects, such as the construction of new highways, must 
``conform'' to (i.e., be consistent with) the part of the State's air 
quality plan that addresses pollution from cars and trucks. Conformity 
to the SIP means that transportation activities will not cause new air 
quality violations, worsen existing violations, or delay timely 
attainment of the NAAQS or any interim milestones. If a transportation 
plan does not conform, most new projects that would expand the capacity 
of roadways cannot go forward. Regulations at 40 CFR part 93 set forth 
EPA policy, criteria, and procedures for demonstrating and assuring 
conformity of such transportation activities to a SIP. The regional 
emissions analysis is one, but not the only, requirement for 
implementing transportation conformity. Transportation conformity is a 
requirement for nonattainment and maintenance areas. Maintenance areas 
are areas that were previously designated nonattainment for a 
particular NAAQS but have since been redesignated to attainment with an 
approved maintenance plan for that NAAQS.
    Under the CAA, States are required to submit at various times 
control strategy SIPs and maintenance plans for nonattainment areas. 
These control strategy SIPs (including reasonable further progress and 
attainment demonstration requirements) and maintenance plans create 
MVEBs for criteria pollutants and/or their precursors to address 
pollution from cars and trucks. Per 40 CFR part 93, a MVEB must be 
established for the last year of the maintenance plan. A State may 
adopt MVEBs for other years as well. The MVEB is the portion of the 
total allowable emissions in the maintenance demonstration that is 
allocated to highway and transit vehicle use and emissions. See 40 CFR 
93.101. The MVEB serves as a ceiling on emissions from an area's 
planned transportation system. The MVEB concept is further explained in 
the preamble to the November 24, 1993, Transportation Conformity Rule. 
See 58 FR 62188. The preamble also describes how to establish the MVEB 
in the SIP and how to revise the MVEB.
    After interagency consultation with the transportation partners for 
the Cincinnati OH-KY Area, Kentucky developed MVEBs for NOX 
and VOC for the Northern Kentucky Area. Kentucky developed these MVEBs 
for the last year of the maintenance plan, in this case 2035, and for 
the interim year of 2026. The 2035 MVEBs reflect the total projected 
on-road emissions for 2035, plus an allocation from the available 
NOX and VOC safety margins. Under 40 CFR 93.101, the term 
``safety margin'' is the difference between the attainment level (from 
all sources) and the projected level of emissions (from all sources) in 
the maintenance plan. The safety margin can be allocated to the 
transportation sector; however, the total emissions must remain below 
the attainment level. The NOX and VOC MVEBs and allocation 
from the safety margin were developed in consultation with the 
transportation partners and were added to account for uncertainties in 
population growth, changes in model vehicle miles traveled, and new 
emission factor models. The NOX and VOC MVEBs for the Area 
are identified in Tables 8 and 9, below.
    Kentucky, in consultation with the transportation partners for the 
Cincinnati OH-KY Area, chose to allocate a portion of the available 
safety margins to the 2026 and 2035 NOX and VOC MVEBs for 
the Area. Kentucky allocated 15 percent (0.90 tpsd) and (0.38 tpsd) of 
the on-road emissions totals to the 2026 NOX and VOC MVEBs, 
respectively. Likewise, Kentucky allocated 15 percent (0.63 tpsd) and 
(0.29 tpsd) of the on-road emissions totals to the 2035 NOX 
and VOC MVEBs, respectively. The total remaining 2035 NOX 
and VOC safety margins after allocations are 10.22 tpsd and 0.47 tpsd, 
respectively. See Tables 7 through 9, below, for additional 
information.

         Table 7--Safety Margins for the Northern Kentucky Area
                                 [tpsd]
------------------------------------------------------------------------
                       Year                            NOX        VOC
------------------------------------------------------------------------
2026..............................................      10.40       1.34
2035..............................................      11.75       1.14
------------------------------------------------------------------------

[[Page 48783]]

    Table 8--NOX On-Road Emissions and MVEBs (2026 and 2035) for the
                         Northern Kentucky Area
                                 [tpsd]
------------------------------------------------------------------------
          NOX on-road emissions                2026            2035
------------------------------------------------------------------------
Boone...................................            2.65            2.00
Campbell................................            0.94            0.57
Kenton..................................            2.44            1.64
                                         -------------------------------
    Totals..............................            6.02            4.21
    NOX Safety Margin Allocated to MVEB.            0.90            0.63
        NOX MVEBs.......................            6.92            4.84
------------------------------------------------------------------------

    Table 9--VOC On-Road Emissions and MVEBs (2026 and 2035) for the
                         Northern Kentucky Area
                                 [tpsd]
------------------------------------------------------------------------
          VOC on-road emissions                2026            2035
------------------------------------------------------------------------
Boone...................................            1.03            0.86
Campbell................................            0.51            0.36
Kenton..................................            1.02            0.74
                                         -------------------------------
    Totals..............................            2.56            1.96
    VOC Safety Margin Allocated to MVEBs            0.38            0.29
        VOC MVEBs.......................            2.94            2.25
------------------------------------------------------------------------

    Kentucky, in consultation with the transportation partners for the 
Cincinnati OH-KY Area, chose to allocate a portion of the available 
safety margins (Table 7) to the 2026 and 2035 NOX and VOC 
MVEBs for the Area. Kentucky allocated 15 percent (0.90 tpsd) and (0.38 
tpsd) of the on-road emissions totals to the 2026 NOX and 
VOC MVEBs, respectively. Likewise, Kentucky allocated 15 percent (0.63 
tpsd) and (0.29 tpsd) of the on-road emissions totals to the 2035 
NOX and VOC MVEBs, respectively. The total remaining 2035 
NOX and VOC safety margins after allocations are 10.22 tpsd 
and 0.47 tpsd, respectively.
    Through this proposed rulemaking, EPA is proposing to approve the 
MVEBs for NOX and VOC for years 2026and 2035 for the Area 
because EPA has determined that the Area maintains the 2015 8-hour 
ozone NAAQS with the emissions at the levels of the budgets. If the 
MVEBs for the Area are approved or found adequate (whichever comes 
first), they must be used for future conformity determinations.

VII. EPA's Adequacy Determination for the Proposed NOX and VOC MVEBs

    When reviewing submitted ``control strategy'' SIPs or maintenance 
plans containing MVEBs, EPA may affirmatively find the MVEB contained 
therein adequate for use in determining transportation conformity. Once 
EPA affirmatively finds the submitted MVEB is adequate for 
transportation conformity purposes, that MVEB 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 MVEB are 
set out in 40 CFR 93.118(e)(4). The process for determining adequacy 
consists of three basic steps: public notification of a SIP submission, 
a public comment period, and EPA's adequacy determination. This process 
for determining the adequacy of submitted MVEBs for transportation 
conformity purposes was initially outlined in EPA's May 14, 1999, 
guidance, ``Conformity Guidance on Implementation of March 2, 1999, 
Conformity Court Decision.'' EPA adopted regulations to codify the 
adequacy process in the Transportation Conformity Rule Amendments in an 
action titled ``New 8-Hour Ozone and PM2.5 National Ambient 
Air Quality Standards and Miscellaneous Revisions for Existing Areas; 
Transportation Conformity Rule Amendments--Response to Court Decision 
and Additional Rule Change,'' on July 1, 2004. See 69 FR 40004. 
Additional information on the adequacy process for transportation 
conformity purposes is available in the proposed rule titled 
``Transportation Conformity Rule Amendments: Response to Court Decision 
and Additional Rule Changes.'' See 68 FR 38974 (June 30, 2003).
    As discussed earlier, Kentucky's maintenance plan includes 
NOX and VOC MVEBs for the Northern Kentucky Area for the 
interim year 2026 and for 2035, the last year of the maintenance plan. 
EPA reviewed the NOX and VOC MVEBs through the adequacy 
process described in Section I.
    EPA intends to make its determination on the adequacy of the 2026 
and 2035 MVEBs for the Area for transportation conformity purposes in 
the near future by completing the adequacy process that was started on 
September 28, 2022. If EPA finds the 2026 and 2035 MVEBs adequate or 
approves them, the new MVEBs for NOX and VOC must be used 
for future transportation conformity determinations. For required 
regional emissions analysis years, the applicable budgets established 
in this maintenance plan that involve 2026 through 2034, the new 2026 
MVEBs will be used, and for years 2035 and beyond, the applicable 
budgets will be the new 2035 MVEBs established in the maintenance plan.

VIII. Effect of EPA's Proposed Actions

    EPA's proposed actions establish the basis upon which EPA may take 
final action on the issues being proposed for approval. Approval of 
Kentucky's redesignation request would change the legal designation of 
the portions of Boone, Campbell, and Kenton Counties in the Northern 
Kentucky Area, found at 40 CFR part 81, from nonattainment to 
attainment for the 2015 8-hour ozone NAAQS. Approval of Kentucky's 
associated SIP revision would also incorporate a plan for maintaining 
the 2015 8-hour ozone NAAQS in the Area through 2035 into the Kentucky 
SIP. The maintenance plan establishes NOX and VOC MVEBs for 
2026 and 2035 for the Area and includes contingency

[[Page 48784]]

measures to remedy any future violations of the 2015 8-hour ozone NAAQS 
and procedures for evaluating potential violations.

IX. Proposed Actions

    EPA is proposing to: (1) Approve the maintenance plan for the 
Northern Kentucky Area, including the NOX and VOC MVEBs for 
2026 and 2035, and incorporate it into the Kentucky SIP, and (2) 
approve Kentucky's redesignation request for the 2015 8-hour ozone 
NAAQS for the Area. Further, as part of this proposed action, EPA is 
also describing the status of its adequacy determination for the 
NOX and VOC MVEBs for the 2026 and 2035 in accordance with 
40 CFR 93.118(f)(1). Within 24 months from the effective date of EPA's 
adequacy determination for the MVEBs or the effective date for the 
final rule for this action, whichever is earlier, the transportation 
partners will need to demonstrate conformity to the new NOX 
and VOC MVEBs pursuant to 40 CFR 93.104(e)(3). If finalized, approval 
of the redesignation request would change the official designation of a 
portion of Boone, Campbell, and Kenton Counties in Kentucky for the 
2015 8-hour ozone NAAQS from nonattainment to attainment, as found at 
40 CFR part 81.

X. Statutory and Executive Order Reviews

    Under the CAA, redesignation of an area to attainment and the 
accompanying approval of a maintenance plan under section 107(d)(3)(E) 
are actions that affect the status of a geographical area and do not 
impose any additional regulatory requirements on sources beyond those 
imposed by State law. A redesignation to attainment does not in and of 
itself create any new requirements, but rather results in the 
applicability of requirements contained in the CAA for areas that have 
been redesignated to attainment. Moreover, the Administrator is 
required to approve a SIP submission that complies with the provisions 
of the Act and applicable Federal regulations. 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 CAA. 
These actions merely propose to approve State law as meeting Federal 
requirements and do not impose additional requirements beyond those 
imposed by State law. For that reason, these proposed actions:
     Are not significant regulatory actions 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);
     Do not impose an information collection burdens under the 
provisions of the Paperwork Reduction Act (44 U.S.C. 3501 et seq.);
     Are certified as not having a significant economic impact 
on a substantial number of small entities under the Regulatory 
Flexibility Act (5 U.S.C. 601 et seq.);
     Do not contain any unfunded mandate or significantly or 
uniquely affect small governments, as described in the Unfunded 
Mandates Reform Act of 1995 (Pub. L. 104-4);
     Do not have Federalism implications as specified in 
Executive Order 13132 (64 FR 43255, August 10, 1999);
     Are not economically significant regulatory actions based 
on health or safety risks subject to Executive Order 13045 (62 FR 
19885, April 23, 1997);
     Are not significant regulatory actions subject to 
Executive Order 13211 (66 FR 28355, May 22, 2001); and
     Are not subject to requirements of section 12(d) of the 
National Technology Transfer and Advancement Act of 1995 (15 U.S.C. 272 
note) because application of those requirements would be inconsistent 
with the CAA.
    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 rules do not have tribal implications as specified by 
Executive Order 13175 (65 FR 67249, November 9, 2000).
    Executive Order 12898 (Federal Actions To Address Environmental 
Justice in Minority Populations and Low-Income Populations, 59 FR 7629, 
Feb. 16, 1994) directs Federal agencies to identify and address 
``disproportionately high and adverse human health or environmental 
effects'' of their actions on minority populations and low-income 
populations to the greatest extent practicable and permitted by law. 
EPA defines environmental justice (EJ) as ``the fair treatment and 
meaningful involvement of all people regardless of race, color, 
national origin, or income with respect to the development, 
implementation, and enforcement of environmental laws, regulations, and 
policies.'' EPA further defines the term fair treatment to mean that 
``no group of people should bear a disproportionate burden of 
environmental harms and risks, including those resulting from the 
negative environmental consequences of industrial, governmental, and 
commercial operations or programs and policies.''
    The Cabinet and District did not evaluate environmental justice 
considerations as part of its redesignation request or SIP submittal; 
the CAA and applicable implementing regulations neither prohibit nor 
require such an evaluation. EPA did not perform an EJ analysis and did 
not consider EJ as part of Kentucky's redesignation request or SIP 
submittal in these proposed actions. Consideration of EJ is not 
required as part of these proposed actions, and there is no information 
in the record inconsistent with the stated goal of E.O. 12898 of 
achieving environmental justice for people of color, low-income 
populations, and Indigenous peoples.

List of Subjects

 40 CFR Part 52

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

40 CFR Part 81

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

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

Jeaneanne Gettle,
Acting Regional Administrator, Region 4.
[FR Doc. 2023-16223 Filed 7-27-23; 8:45 am]
BILLING CODE 6560-50-P