[Federal Register Volume 88, Number 97 (Friday, May 19, 2023)]
[Rules and Regulations]
[Pages 32594-32615]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2023-10563]


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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Parts 52 and 81

[EPA-R05-OAR-2022-0004; FRL-9629-04-R5]


Air Plan Approval; Michigan; Redesignation of the Detroit, MI 
Area to Attainment of the 2015 Ozone Standards

AGENCY: Environmental Protection Agency (EPA).

ACTION: Final rule.

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SUMMARY: The Environmental Protection Agency (EPA) is finalizing its 
redesignation of the Detroit, Michigan area to attainment for the 2015 
ozone National Ambient Air Quality Standards (NAAQS) in accordance with 
a request from the Michigan Department of Environment, Great Lakes, and 
Energy (EGLE). EGLE submitted this request on January 3, 2022. EPA is 
approving, as a revision to the Michigan State Implementation Plan 
(SIP), the State's plan for maintaining the 2015 ozone NAAQS through 
2035 in the Detroit area. EPA is also finding adequate and approving 
Michigan's 2025 and 2035 volatile organic compound (VOC) and oxides of 
nitrogen (NOX) motor vehicle emissions budgets (budgets) for 
the Detroit area. The Detroit area includes Livingston, Macomb, Monroe, 
Oakland, St. Clair, Washtenaw, and Wayne Counties.

DATES: This final rule is effective on May 19, 2023.

ADDRESSES: EPA has established a docket for this action under Docket ID 
No. EPA-R05-OAR-2022-0004. All documents in the docket are listed on 
the www.regulations.gov website. Although listed in the index, some 
information is not publicly available, i.e., Confidential Business 
Information (CBI) or other information whose disclosure is restricted 
by statute. Certain other material, such as copyrighted material, is 
not placed on the internet and will be publicly available only in hard 
copy form. Publicly available docket materials are available either 
through www.regulations.gov or at the Environmental Protection Agency, 
Region 5, Air and Radiation Division, 77 West Jackson Boulevard, 
Chicago, Illinois 60604. This facility is open from 8:30 a.m. to 4:30 
p.m., Monday through Friday, excluding Federal holidays and facility 
closures due to COVID-19. We recommend that you telephone Eric Svingen, 
Environmental Engineer, at (312) 353-4489 before visiting the Region 5 
office.

FOR FURTHER INFORMATION CONTACT: Eric Svingen, Environmental Engineer, 
Attainment Planning and Maintenance Section, Air Programs Branch (AR-
18J), Environmental Protection Agency, Region 5, 77 West Jackson 
Boulevard, Chicago, Illinois 60604, (312) 353-4489, 
[email protected].

SUPPLEMENTARY INFORMATION: Throughout this document whenever ``we,'' 
``us,'' or ``our'' is used, we mean EPA.

I. Background

    EPA is redesignating the Detroit area to attainment of the 2015 
ozone standard, in accordance with EGLE's January 3, 2022, submission. 
The background for this action is discussed in detail in EPA's 
proposal, dated March 14, 2022 (87 FR 14210). In that proposal, we 
noted that, under EPA's regulations at 40 CFR part 50, the 2015 ozone 
NAAQS is attained in an area when the 3-year average of the annual 
fourth highest daily maximum 8-hour average concentration (i.e., the 
design value) is equal to or less than 0.070 parts per million (ppm), 
when truncated after the thousandth decimal place, at all of the ozone 
monitoring sites in the area. (See 40 CFR 50.19 and appendix U to 40 
CFR part 50.) Under the Clean Air Act (CAA), EPA may redesignate 
nonattainment areas to attainment if complete, quality-assured data 
show that the area has attained the standard and the area meets the 
other CAA redesignation requirements in section 107(d)(3)(E). The 
proposed rule provides a detailed discussion of how Michigan has met 
these CAA requirements and EPA's rationale for approving the 
redesignation request.
    As discussed in the proposed rule, quality-assured and certified 
monitoring data for 2019-2021 show that the area has attained the 2015 
ozone standard, and EPA has determined that the

[[Page 32595]]

attainment is due to permanent and enforceable measures. In the 
maintenance plan submitted for the area, Michigan has demonstrated that 
compliance with the ozone standard will be maintained in the area 
through 2035. As also discussed in the proposed rule, Michigan has 
adopted 2025 and 2035 VOC and NOX motor vehicle emissions 
budgets for the area that are supported by Michigan's maintenance 
demonstration.
    Michigan has met the requirements applicable to redesignations 
through various SIP submittals. On July 6, 2022 (87 FR 40097), 
consistent with conditions identified in our proposed rulemaking, EPA 
approved portions of separate December 18, 2020, submittals as meeting 
the applicable requirements for a base year emissions inventory and an 
emissions statement program. In this rulemaking EPA is also approving, 
as a revision to the Michigan SIP, the State's maintenance plan for the 
area. The maintenance plan is designed to keep the Detroit area in 
attainment of the 2015 ozone NAAQS through 2035. Additionally, EPA is 
finding adequate and approving Michigan's newly established 2025 and 
2035 motor vehicle emissions budgets for NOX and VOCs for 
the area. With these approvals of Michigan's SIP submissions, all SIP 
requirements applicable to redesignation are fully approved.
    After publication of the proposed rule, EPA finalized two 
additional rulemakings related to the attainment status of the Detroit 
nonattainment area. First, on February 1, 2023, EPA found that the 
Detroit area failed to attain the 2015 ozone NAAQS by its Marginal 
attainment date of August 3, 2021, based on the area's design value as 
of the attainment date (i.e., monitoring data from 2018-2020). As a 
result of that determination, the area was reclassified by operation of 
law to Moderate, with SIP submissions associated with the Moderate area 
classification due March 1, 2023 (88 FR 6633). As described below in 
EPA's response to comments, consistent with EPA's longstanding 
interpretation of CAA section 107(d)(3)(E)(ii) and (v), and as 
described in the final determination and classification, EPA's role is 
to assess whether Michigan adequately addressed all requirements 
applicable to redesignation that applied to Detroit on the date of 
EGLE's submittal (88 FR 6633, 6635). Because EGLE submitted a complete 
and approvable redesignation request on January 3, 2022, the Moderate 
area requirements that became due on March 1, 2023, are not applicable 
for purposes of this redesignation. Second, EPA has issued a 
determination that the area is attaining the 2015 ozone NAAQS based on 
air quality monitoring data from 2020-2022, i.e., a clean data 
determination. In issuing the clean data determination, EPA took notice 
and comment on its concurrence on a January 26, 2023, exceptional 
events demonstration submitted by EGLE. The demonstration requested 
exclusion of wildfire event-influenced data from the 2020-2022 design 
value period for the 2015 ozone NAAQS for the Detroit nonattainment 
area.

II. Motor Vehicle Emission Budgets

    Under section 176(c) of the CAA, new transportation plans, 
programs, or projects that receive Federal funding or support, such as 
the construction of new highways, must ``conform'' to (i.e., be 
consistent with) the SIP. Conformity to the SIP means that 
transportation activities will not cause or contribute to any new air 
quality violations, increase the frequency or severity of any existing 
air quality violations, or delay timely attainment or any required 
interim emissions reductions or any other milestones. Transportation 
conformity continues to apply in areas redesignated to attainment with 
a maintenance plan, so the Detroit area will continue to be subject to 
transportation conformity requirements.
    As shown in Table 1, Michigan's maintenance plan includes 
NOX and VOC motor vehicle emission budgets (``budgets'') for 
the Detroit area for 2025, the interim year, and 2035, the last year of 
the maintenance period. The budgets are the portion of the total 
allowable emissions that are allocated to highway and transit vehicle 
use that, together with emissions from other sources in the Detroit 
area, are projected to result in air quality that either attains or 
maintains the NAAQS. These budgets represent the projected 2025 and 
2035 on-road emissions plus a safety margin allocation and are 
consistent with the State's demonstration of maintenance of the 2015 
ozone NAAQS. The safety margin and the allocation of a portion of it to 
the motor vehicle emissions budgets are described below. Detailed 
information on the transportation conformity program can be found in 
our March 14, 2022, proposed approval of Michigan's redesignation 
request (87 FR 14210).

          Table 1--2025 and 2035 Budgets for the Detroit Area for the 2015 Ozone NAAQS Maintenance Plan
                                              [Tons per summer day]
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                                              2025 Interim year                    2035 Maintenance year
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                                     Projected      Safety                  Projected      Safety
                                      on-road       margin       Total       on-road       margin       Total
                                     emissions    allocation     budget     emissions    allocation     budget
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NOX...............................        61.20        43.15       104.35        40.30        62.11       102.41
VOCs..............................        34.40        13.46        47.86        22.00        22.67        44.67
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    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. Further, the transportation 
conformity regulations allow states to allocate all or a portion of a 
documented safety margin to the motor vehicle emissions budgets for an 
area (40 CFR 93.124(a)). Michigan is allocating a considerable portion 
of that safety margin to the mobile source sector. Specifically, in 
2025, Michigan is allocating 43.15 tons per summer day (TPSD) and 13.46 
TPSD of the NOX and VOC safety margins, respectively, 
representing approximately 65 percent of the available safety margins, 
to the motor vehicle emissions budgets. In 2035, Michigan is allocating 
62.11 TPSD and 22.67 TPSD of the NOX and VOC safety margins, 
respectively, representing approximately 65 percent of the available 
safety margins, to the motor vehicle emissions budgets. Since only a 
part of the safety margin is being used for this purpose, maintenance 
requirements are still met. Once allocated to mobile sources, these 
portions of the safety margins will not be available for use by other 
sources.

[[Page 32596]]

III. Environmental Justice (EJ) Considerations

    To identify environmental burdens and susceptible populations in 
communities in the Detroit area, EPA performed a screening-level 
analysis using EPA's EJ screening and mapping tool (``EJSCREEN'').\1\ 
EPA utilized EJSCREEN to evaluate environmental and demographic 
indicators at the county level for each county within the area 
(Livingston, Macomb, Monroe, Oakland, St. Clair, Washtenaw, and Wayne 
Counties).
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    \1\ See documentation on EPA's Environmental Justice Screening 
and Mapping Tool at https://www.epa.gov/ejscreen.
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    EJSCREEN provides environmental indicators for 12 pollutants or 
sources, which include fine particulate matter (PM2.5), 
ozone, air toxics cancer risk, traffic proximity, lead paint, Superfund 
site proximity, underground storage tanks, and wastewater discharge. Of 
the seven counties in the Detroit area, all but St. Clair County score 
at or above the 80th percentile nationally for at least one indicator: 
Livingston County for Superfund site proximity and wastewater; Macomb 
County for PM2.5, traffic proximity, Superfund site 
proximity, and underground storage tanks; Monroe County for ozone; 
Oakland County for traffic proximity, underground storage tanks, and 
wastewater; Washtenaw County for underground storage tanks; and Wayne 
County for PM2.5, air toxics cancer risk, traffic proximity, 
lead paint, underground storage tanks, and wastewater discharge.
    EPA's screening-level analysis indicates that, of the seven 
counties in the Detroit area, only Wayne County scores above the 
national average for the EJSCREEN ``Demographic Index'', which is the 
average of an area's percent minority and percent low-income 
populations, i.e., the two demographic indicators explicitly named in 
Executive Order 12898. As discussed in EPA's EJ technical guidance, 
people of color and low-income populations often experience greater 
exposure and disease burdens than the general population, which can 
increase their susceptibility to adverse health effects from 
environmental stressors.\2\ As a function in part of its relatively 
high demographic index, Wayne County is the only county in the Detroit 
area scoring at or above the 80th percentile in at least one EJ Index, 
which is derived by combining a single environmental factor with the 
demographic indicator. Specifically, Wayne County has EJ Indexes above 
the 80th percentile in PM2.5, ozone, traffic proximity, lead 
paint, and underground storage tanks. EPA has provided that if any of 
the EJ indexes for the areas under consideration are at or above the 
80th percentile nationally, then further review may be appropriate.\3\
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    \2\ EPA, ``Technical Guidance for Assessing Environmental 
Justice in Regulatory Analysis,'' section 4 (June 2016).
    \3\ EPA, ``EJSCREEN Technical Documentation,'' appendix H 
(September 2019).
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    For further review, EPA has evaluated the ozone monitor trends and 
determined that all the monitors in the nonattainment area are 
similarly demonstrating attainment and therefore, there is no evidence 
that any one community is experiencing different air quality for this 
NAAQS from another. To consider whether the improvement in air quality 
has been observed throughout the area, including the portions of the 
area containing communities that are pollution-burdened and 
underserved, EPA conducted an additional analysis of historical ozone 
design values in the Detroit area. Specifically, EPA reviewed data from 
the seven monitors in the area that have been operating since the 2001-
2003 design value period: the Macomb County monitor at New Haven with 
Site ID 26-099-0009, the Macomb County monitor at Warren with Site ID 
26-099-1003, the Oakland County monitor at Oak Park with Site ID 26-
125-0001, the St. Clair County monitor at Port Huron with Site ID 26-
147-0005, the Washtenaw County monitor at Ypsilanti with Site ID 26-
161-0008, the Wayne County monitor at Allen Park with Site ID 26-163-
0001, and the Wayne County monitor at East 7 Mile with Site ID 26-163-
0019. Ozone design values in the Detroit area have declined 
significantly from 0.097 ppm in 2001-2003 to 0.070 ppm in 2019-2021. As 
shown in Table 2, the improvement in air quality has been observed at 
every monitor in the Detroit area. Specifically, ozone design values at 
each monitor have improved by between 20% and 31%.

          Table 2--Improvement in Ozone Design Values Between the 2001-2003 Period and 2019-2021 Period
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                                                                                                   Improvement
                                              2001-2003         2010-2012         2019-2021      between  2001-
                 Monitor                    Design value      Design value      Design value     2003 and 2019-
                                                (ppm)             (ppm)             (ppm)           2021 (%)
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New Haven...............................             0.097             0.078             0.068                30
Warren..................................             0.095             0.079             0.066                31
Oak Park................................             0.091             0.078             0.069                24
Port Huron..............................             0.090             0.077             0.070                22
Ypsilanti...............................             0.091             0.076             0.066                27
Allen Park..............................             0.084             0.074             0.067                20
East 7 Mile.............................             0.091             0.081             0.070                23
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    Not only have ozone design values at all monitors improved by the 
relatively consistent margin of 20% to 31%, but the design values at 
all monitors have been relatively consistent within each 3-year period.

IV. Response to Comments

    Upon publication of the March 14, 2022, proposed rulemaking, EPA 
opened a 30-day comment period, ending April 13, 2022 (87 FR 14210). On 
April 4, 2022, in response to a request from Sierra Club, EPA extended 
the comment period by an additional 14 days through April 27, 2022 (87 
FR 19414). During the comment period EPA received three supportive 
comment letters and three adverse comment letters. Two adverse comment 
letters were submitted by students at the University of Michigan. The 
third adverse comment letter was submitted by Sierra Club and Great 
Lakes Environmental Law Center (GLELC), on behalf of themselves and 19 
other groups based in Michigan. On March 14, 2023, after the close of 
the comment period for this rulemaking or any rulemaking relating to 
the Detroit area,

[[Page 32597]]

GLELC and Sierra Club sent what they described as ``supplemental 
comments'' regarding the proposed redesignation. EPA is exercising its 
discretion to respond to these comments herein. Summaries of the 
adverse comments and EPA's responses are provided below.
    Comment: Two students at the University of Michigan raised concerns 
with EPA's proposed approval of EGLE's redesignation request. One 
student shared their fear that redesignating the Detroit area could 
increase ground-level ozone and suggested that deregulation in the past 
has ``worsened our fight against climate change.'' The second student 
raised concerns about Detroit's air quality, given the existence of 
power plants and other facilities in the area. Given EPA's April 13, 
2022, proposed determination that the Detroit area failed to attain the 
2015 ozone NAAQS by its attainment date based on 2018-2020 data, this 
student believes it is inappropriate to reevaluate the area's legal 
designation at this time. This student suggested that ``legal status 
should only be considered when changes have been made and have been 
upheld over a substantial period of time.''
    Response: These commenters raise issues that are similar to the 
concerns of Sierra Club and GLELC, which we discuss more extensively 
below.
    A redesignation to attainment does not remove any emission control 
measures for existing sources that are already adopted into the EPA 
approved SIP for Michigan. As we discuss below and in the March 14, 
2022, proposal, EGLE's redesignation request includes a demonstration 
that attainment of the 2015 ozone NAAQS was attributable to permanent 
and enforceable emissions reductions. Further, EGLE's January 3, 2022, 
submission includes a plan to maintain the NAAQS through 2035 in the 
Detroit area, as well as a contingency plan that would be triggered if 
the area were to violate the 2015 ozone NAAQS in the future. While EPA 
agrees that climate change is an important issue, this rulemaking 
addresses the separate issue of the Detroit area's designation for the 
2015 ozone NAAQS.
    Regarding concerns about the existence of power plants and other 
industrial facilities in the area, we refer the commenter to Table 2 in 
EPA's March 14, 2022, proposal, which shows significant emissions 
decreases in the Detroit area from 2014 to 2019. Specifically, 
NOX and VOC emissions from point, nonpoint, on-road, and 
nonroad sources in the Detroit area declined by 203.21 tons per ozone 
season day and 104.33 tons per ozone season day, respectively, between 
2014 and 2019. Decreases in NOX and VOC emissions from point 
sources, which is the category including power plants, account for 
69.85 TPSD and 18.50 TPSD, respectively, of the total decrease. These 
emissions decreases have contributed to the gradual reductions in ozone 
concentrations in the Detroit area. Further discussion of the 
commenter's suggestion that EPA should delay action on Michigan's 
redesignation request is found below.

A. Monitoring Data

    Comment: Sierra Club and GLELC observe that the Detroit area 
attained the 2015 ozone NAAQS, but they raise concerns that the 
``margin for NAAQS compliance is particularly thin'' at two monitors in 
the Detroit area. The commenters predict future values at which the 
NAAQS would be exceeded at four monitors in the area, and raise 
additional concerns that the area may violate the NAAQS during the 2022 
ozone season. The commenters contend that, in order to approve a 
redesignation request, EPA must find that the improvement in air 
quality is ``permanent'' and the result of ``enforceable reductions to 
emissions,'' and that, in this case, neither of those conditions has 
been met.
    Response: The 2015 ozone NAAQS is defined at 40 CFR 50.19, and 
appendix U to 40 CFR part 50 contains the data handling conventions and 
computations necessary for determining whether the NAAQS has been met 
at a monitoring site. To attain the 2015 ozone NAAQS, the 3-year 
average of the annual fourth-highest daily maximum 8-hour average ozone 
concentrations (ozone design values) at each monitor must not exceed 
0.070 ppm. As described in appendix U, design values are reported in 
ppm to three decimal places, with additional digits to the right of the 
third decimal place truncated.
    The commenters conflate two separate demonstrations that are 
required under the statutory criteria for redesignation. CAA section 
107(d)(3)(E)(i) provides that EPA may not promulgate a redesignation to 
attainment unless the Administrator ``determines that the area has 
attained the national ambient air quality standard.'' In finding that 
an area has met the first criterion, the statute does not require EPA 
to assess how long that attainment has been occurring for or by what 
margin the area is attaining. Therefore, the margin by which an area 
(or monitor) attains the NAAQS is not relevant to the question of 
whether or not the area is attaining the NAAQS. Separately, CAA section 
107(d)(3)(E)(iii) provides that the Administrator must also determine 
``that the improvement in air quality is due to permanent and 
enforceable reductions in emissions resulting from implementation of 
the applicable implementation plan and applicable Federal air pollutant 
control regulations and other permanent and enforceable reductions.'' 
As used in CAA section 107(d)(3)(E), the term ``permanent'' does not 
describe the improvement in air quality, as commenters suggest, but 
instead describes the emissions reductions to which attainment must be 
attributable.
    Michigan's plan for maintaining the NAAQS is relevant under CAA 
section 107(d)(3)(E)(iv), which provides that the Administrator must 
fully approve ``a maintenance plan for the area as meeting the 
requirements of section 175A.'' The requirement for a maintenance plan 
includes the requirement for contingency provisions to be triggered 
should an area violate the NAAQS after redesignation, which illustrates 
that the CAA anticipates some possibility that areas may in the future 
violate the NAAQS despite meeting all requirements under CAA section 
107(d)(3)(E). In this final rule EPA is approving EGLE's plan for 
maintaining the NAAQS through 2035, as described below and in the 
proposed rule.

B. Planning Requirements

    Comment: Sierra Club and GLELC raise concerns that redesignation 
``could jeopardize public health by unnecessarily delaying needed air 
quality planning requirements.'' The commenters note EPA's separate 
proposal to reclassify the Detroit area as Moderate, which would 
trigger new requirements for SIP submissions. The commenters allege 
that redesignation would ``prematurely halt ongoing planning efforts to 
reduce NOX and VOCs'' and without a nonattainment 
designation the State will face ``no obligation to select or implement 
any of these control measures to assure ozone levels are maintained 
below the NAAQS.'' The commenters allege that although ``similar 
discussions and planning might resume upon redesignation to 
nonattainment, there could be several years of delay in the meantime 
while excess ozone levels endanger public health.'' The commenters 
reference requirements for Reasonably Available Control Technology 
(RACT), and the potential for reductions in NOX emissions 
from the Monroe power plant, claiming that this facility emitted 15,219 
tons of NOX in 2014.

[[Page 32598]]

    Response: In a separate rulemaking published April 13, 2022, EPA 
proposed to reclassify the Detroit area as Moderate, based on air 
quality data from 2018-2020 showing the Detroit area failed to attain 
the 2015 ozone NAAQS by its Marginal attainment date. EPA finalized the 
reclassification as Moderate on February 1, 2023, and established a 
deadline of March 1, 2023, for most SIP revisions associated with 
Moderate area requirements, including requirements for an attainment 
plan and RACT. However, upon the effective date of this redesignation 
to attainment, nonattainment requirements, including Moderate area 
requirements, will no longer apply to the Detroit area.
    As described below, if the Detroit area violates the 2015 ozone 
NAAQS after this redesignation, then Michigan would be required to 
implement its contingency plan to bring the area back into attainment. 
The contingency provisions submitted by EGLE include adoption or 
expansion of NOX RACT rules and/or VOC RACT rules for 
existing stationary sources. This is the construct of the CAA with 
regard to redesignated attainment areas to provide for protections 
associated with air quality in designated attainment areas. It should 
be noted that many sources that would be subject to VOC RACT under the 
2015 ozone NAAQS have implemented VOC controls as required by the rules 
Michigan adopted to meet VOC RACT requirements under the 1979 ozone 
NAAQS. See 59 FR 46182, September 7, 1994.
    To illustrate the example of a facility with high NOX 
emissions which could be subject to additional control requirements, 
the commenters reference the Monroe power plant, and incorrectly claim 
this facility emitted 15,219 tons of NOX in 2014. According 
to EPA's 2014 National Emissions Inventory (NEI), the Monroe power 
plant emitted 8,320 tons of NOX in 2014.\4\ A separate data 
source, EPA's Clean Air Markets Program Data (CAMPD), shows a similar 
result of 8,296 tons of NOX in 2014.\5\ However, as shown in 
the CAMPD database, more recent emissions data indicate reduced 
NOX emissions and improved control efficiency at this 
facility. NOX emissions from the Monroe facility declined by 
45% between 2014 and 2021, even though heat input declined by only 5% 
over the same period.\6\ Because heat input corresponds to power 
generation, these data show that the significant decrease in 
NOX emissions was not due to significantly decreased 
operation of the facility. Rather, the decrease in NOX 
emissions is attributable to increased efficacy of pollution control 
equipment that was installed and operated to reduce NOX 
emissions. Specifically, Monroe power plant has Selective Catalytic 
Reduction (SCR) NOX controls on all four units. The most 
recent installation of SCR was in November of 2014, and therefore would 
have been minimally represented in the 2014 emissions data. As 
discussed in more detail further below, these significant reductions in 
NOX emissions from Electric Generating Units (EGUs) such as 
the Monroe facility can be attributed to permanent and enforceable 
measures such as the Cross-State Air Pollution Rule (CSAPR), which is a 
Federal rule that established emissions budgets designed to incentivize 
the installation and operation of emissions controls.
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    \4\ https://www.epa.gov/air-emissions-inventories/2014-national-emissions-inventory-nei-data.
    \5\ https://campd.epa.gov/.
    \6\ In 2014, heat input was 157,824,072 Metric Million British 
Thermal Units (MMBtu) and NOX emissions were 8,296 tons. 
In 2021, heat input was 149,865,102 MMBtu and NOX 
emissions were 4,544 tons.
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    The commenters also raise concerns that implementation of Moderate 
area requirements could be delayed by a violation of the 2015 ozone 
NAAQS subsequent to redesignation. The commenters speculate that under 
this scenario EPA would redesignate the area to nonattainment in 2023 
and set a new attainment date for three years later, which would be 
2026. As discussed below, under the CAA, a violation of the NAAQS after 
redesignation to attainment does not trigger an automatic redesignation 
to nonattainment. Rather, as discussed above, the initial required 
action under such circumstances would be the State's implementation of 
the contingency provisions in a State's approved maintenance plan for 
the relevant NAAQS, and Michigan's maintenance plan here would require 
the State to implement the contingency provisions more quickly than the 
three-year timeline identified by the commenters. The redesignation of 
an area to nonattainment under section 107(d)(3) is discretionary, and 
could take significantly longer whether initiated at the request of the 
State or by EPA itself.

C. Environmental Justice Concerns

    Comment: The commenters state that EPA must consider environmental 
justice in this action, as much of the nonattainment area contains 
already overburdened communities facing disproportionate environmental 
impacts. The commenters reference various rates of asthma incidence 
across demographic or geographic groups, including asthma rates in 
Detroit that are higher than rates in the rest of Michigan, and rates 
of asthma hospitalizations within both Wayne and Washtenaw counties 
that are higher for Black children relative to white children. The 
commenters also raise concerns that ``the asthma burden in Detroit 
appears to be worsening'' and reference statistics showing that asthma 
rates for adults in Detroit increased from 15.5% in 2016 to 16.2% in 
2021. In support of their comments, the commenters reference a peer-
reviewed study from 2009 associating ozone exposure with health effects 
on adults with asthma in Atlanta. Additionally, the commenters contend 
that EPA has not followed the portion of Executive Order 12898 that 
calls for ``meaningful involvement'' from impacted communities beyond 
the minimum requirements for a rulemaking. The commenters further 
contend that EPA ``must also consider Title VI of the Civil Rights Act 
in evaluating the disproportionate consequences of prematurely 
approving'' the redesignation request. Commenters cite 40 CFR 7.35(b) 
to state that EGLE cannot use ``criteria or methods of administering 
its program which have the effect of subjecting individuals to 
discrimination because of their race, color, [or] national origin''. 
Commenters then state that ``[g]iven the links between ozone pollution 
and asthma as well as the racial disparities regarding asthma burdens 
in Michigan, there is significant risk of EPA's decision violating 
Title VI's prohibition'' against administering programs in a manner 
that has a discriminatory effect. Commenters end this portion of the 
comments by stating, ``It's unclear how, if at all, EGLE or EPA 
accounted for the Title VI requirements and ensured compliance in 
regards to this proposal.''
    Response: EPA is committed to the meaningful involvement and fair 
treatment of vulnerable populations disproportionately affected by 
pollution. EPA does not agree with all of the commenters' 
characterizations in this letter. EPA has considered both environmental 
justice and title VI of the Civil Rights Act in the context of this 
action, and an overview of EPA's considerations of both are described 
below. Further, EPA has complied with public notice and comment 
requirements for this action.
    With regard to EPA's consideration of environmental justice, EPA is 
aware of the demographic data for the Detroit nonattainment area that 
is the subject of this final action. EPA acknowledges that the Detroit 
area includes communities that are pollution-burdened and underserved. 
As described above, EPA considered this information as it

[[Page 32599]]

pertains to actions being taken in this action, and further discussion 
on this consideration is below in this response.
    Consistent with regulatory obligations associated with this action, 
EPA held a public notice and comment period for this action. In 
addition, EPA conducted related outreach with Detroit community 
members, advocacy groups, and local government officials, regarding air 
quality issues that have been identified as priorities by these 
stakeholders. In a meeting EPA held with representatives from the City 
of Detroit, Michigan Environmental Council, GLELC, Southwest Detroit 
Environmental Vision, and the Ecology Center regarding a separate 
regulatory action, following a presentation by EPA and a roundtable 
discussion with these stakeholders, EPA solicited opinions from these 
stakeholders regarding topics for future meetings.\7\ EPA suggested 
three topics: permitting, enforcement and inspections, and ground-level 
ozone, which we explained included our proposed redesignation. Of those 
stakeholders who shared an opinion, all voiced interest in topics other 
than ozone, and no stakeholders indicated an interest in future 
engagement on ozone. Through community engagement, EPA took steps to 
understand different levels of public interest for different 
rulemakings that were impacting the Detroit, MI area on more than one 
topic around the same time (which was in addition to public notice and 
comment requirements).
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    \7\ See Appendix A to May 11, 2023, memorandum entitled 
``Memorandum to the Docket: Technical Support Document for the 
Detroit Redesignation to Attainment for the 2015 Ozone National 
Ambient Air Quality Standard'' (hereafter referred to as May 11, 
2023, TSD).
---------------------------------------------------------------------------

    In addition to communicating directly with stakeholders, EPA went 
beyond the obligations of notice-and-comment rulemaking by issuing a 
press release on the day the proposed redesignation was published in 
the Federal Register.\8\ The press release was picked up by The Detroit 
News, one of the area's two major newspapers.\9\ In its article, The 
Detroit News noted that EPA would be accepting public comments on the 
proposed redesignation. Additionally, on April 4, 2022, EPA extended 
the comment period on the proposed redesignation by 14 days, in 
response to a request from Sierra Club for additional time to ``fully 
review the basis for EPA's proposal and confer with local partners'' 
given Sierra Club's suggestion that the proposed action was a 
``consequential decision impacting environmental justice communities.''
---------------------------------------------------------------------------

    \8\ https://www.epa.gov/newsreleases/epa-and-michigan-propose-detroit-now-meets-federal-air-quality-standard-ozone.
    \9\ https://www.detroitnews.com/story/news/environment/2022/03/14/pollution-reduction-prompts-epa-improve-metro-detroits-air-quality-rating/7041856001.
---------------------------------------------------------------------------

    With regard to the comments concerning the demographics of the 
community and asthma burdens in the area, EPA considered a variety of 
relevant factors in its determination to propose approval of the 
Detroit area redesignation and maintenance plan. Importantly, the 
comment letter indicates that EPA is now ``prematurely'' approving the 
request for redesignation. As is explained throughout this action, this 
action is not premature. Rather, it is consistent with the applicable 
requirements of the CAA for an area to qualify for a redesignation. 
This redesignation request recognizes that the area has achieved a 
national ambient air quality standard and alters the designation of the 
area; however, applicable emission reduction measures remain in effect, 
as do contingency provisions in the maintenance plan now being approved 
that will be triggered if the area fails to continue to attain the 
standards. Additional information is provided below in this response to 
comment.
    Further, under section 109 of the CAA, EPA sets primary, or health-
based, NAAQS for all criteria pollutants to provide requisite 
protection of public health, including the health of at-risk 
populations, with an adequate margin of safety. It establishes 
secondary, or welfare-based, standards to provide requisite protection 
of public welfare from any known or anticipated adverse effects of the 
criteria pollutant in ambient air. In EPA's October 26, 2015, 
rulemaking strengthening the ozone NAAQS to the level of 0.070 ppm, we 
provided a detailed rationale for the Administrator's determination 
that the 2015 ozone NAAQS would be protective of public health (80 FR 
65292). This rationale included explicit consideration of protection 
for people, including children, with asthma.
    EPA considered commenters' concerns regarding asthma rates and 
considered that information in light of the action being finalized. As 
we explained in the October 26, 2015, rulemaking, asthma is a multi-
etiologic disease, and air pollutants, including ozone, represent only 
one potential factor that may trigger an asthma exacerbation.
    Importantly, as is explained throughout this action, if, following 
redesignation, there are increases in ozone that result in a violation 
of the 2015 ozone standard, the contingency provisions of the 
maintenance plan would trigger additional actions by EGLE.
    In support of their comments, the commenters reference a peer-
reviewed study from 2009 associating ozone exposure with health effects 
on adults with asthma in Atlanta.
    As we noted in a Technical Support Document in the docket folder 
for the June 4, 2018, rulemaking designating the Detroit area as 
nonattainment for the 2015 ozone standard, the 2014-2016 design value 
for the area was 0.073 ppm (83 FR 25776). As noted above, the 2019-2021 
design value is 0.070 ppm. The commenters do not clarify how the ozone 
levels in the area might be a primary cause or primary contributor to 
the increase in asthma rates they cite as occurring over that same 
period (between 2016 and 2021).
    As discussed above, the entire Detroit area is attaining the 2015 
ozone NAAQS, which EPA established to provide requisite protection of 
public health, including the health of at-risk populations, with an 
adequate margin of safety.
    EPA also reviewed current and upcoming emission reduction measures 
that are anticipated to further mitigate pollution issues in the 
Detroit area. Existing Federal mobile source and point source emission 
reduction programs will result in ongoing NOX and VOC 
emissions reductions in the Detroit area. For example, NOX 
cap and trade programs such as CSAPR continue to achieve emissions 
reductions that are protective of human health regardless of whether 
EPA redesignates downwind areas for any NAAQS. In addition, the Federal 
Good Neighbor Plan for the 2015 ozone NAAQS is projected to achieve 
emissions reductions that will provide health benefits to populations 
living in proximity to covered facilities beginning in the 2023 ozone 
season. Further, Michigan has submitted a maintenance plan that 
projects continuing reductions in NOX and VOC emissions 
through 2035 from the point, nonpoint, on-road, and nonroad categories, 
based on outputs from EPA's MOVES3 and 2016v2 modeling platforms.
    In addition, EPA is now approving the contingency provisions in 
Michigan's maintenance plan for the Detroit area. As noted elsewhere in 
this rulemaking if the Detroit area were to violate the 2015 ozone 
NAAQS after redesignation, then Michigan would be required to correct 
the violation by expeditiously implementing the contingency provisions 
in its maintenance plan. EPA reviewed the contingency provisions 
submitted by EGLE, and found that many of these actions would benefit

[[Page 32600]]

pollution-burdened and underserved communities that may be located near 
heavily industrial areas (i.e., fuel and diesel retrofit programs, 
which may have significant impacts around truck corridors and rail 
yards).
    Turning to the issues raised regarding title VI of the Civil Rights 
Act of 1964 (title VI), EPA does not agree with commenters' 
characterization of potential concerns raised under title VI. Title VI 
prohibits discrimination by recipients of EPA financial assistance on 
the basis of race, color, or national origin. Under EPA's 
nondiscrimination regulations, which implement title VI and other civil 
rights laws,\10\ recipients of EPA financial assistance are prohibited 
from taking actions in their programs or activities that are 
intentionally discriminatory and/or have an unjustified disparate 
impact.\11\ Because EPA is not a recipient of Federal financial 
assistance, title VI does not apply to EPA itself. EPA carries out its 
mandate to ensure that recipients of EPA financial assistance comply 
with their nondiscrimination obligations by investigating 
administrative complaints filed with EPA alleging discrimination 
prohibited by title VI and the other civil rights laws; \12\ initiating 
affirmative compliance reviews; \13\ and providing technical assistance 
to recipients to assist them in meeting their title VI obligations. 
Importantly, compliance with the CAA does not constitute compliance 
with title VI.
---------------------------------------------------------------------------

    \10\ 40 CFR part 7 and part 5.
    \11\ 40 CFR 7.30 and 7.35.
    \12\ 40 CFR 7.120.
    \13\ 40 CFR 7.115.
---------------------------------------------------------------------------

    As part of this redesignation, EPA is approving the maintenance 
plan for the area, including contingency provisions, which will be 
incorporated into the SIP. Title VI does apply to EGLE as a recipient 
of Federal financial assistance.
    In the context of SIP actions, EPA has evaluated issues similar to 
the title VI comments through CAA section 110(a)(2)(E)(i). See, e.g., 
77 FR 65294 (October 26, 2012); 87 FR 60494 (October 5, 2022). EPA has 
previously acknowledged that it has not issued national guidance or 
regulations concerning implementation of section 110(a)(2)(E) as it 
pertains to consideration of title VI and disparate impacts on the 
basis of race, color, or national origin in the context of the SIP 
program. 87 FR at 60530. Such guidance is forthcoming and will address 
CAA section 110(a)(2)(E)'s necessary assurance requirements as they 
relate to title VI.
    In the context of a SIP action, however, section 110(a)(2)(E) 
requires that a State provide ``necessary assurances'' that the SIP 
submission at issue would not result in violations of any State or 
Federal law. Thus, as the commenters suggest, a relevant inquiry for 
EPA in this rulemaking is whether the air agency has provided adequate 
necessary assurances that implementation of the content of the SIP 
submission at issue is not prohibited by title VI (i.e., implementation 
of the SIP would not result in an unjustified adverse disparate impact 
on the basis of race, color, or national origin). See, e.g., CAA 
section 110(a)(2)(E)(i).
    This redesignation action, at its core, recognizes that an area is 
meeting the NAAQS and has all the required CAA measures in place, 
including the required maintenance plan with contingency provisions. 
The contingency provisions of the maintenance plan would require 
additional control measures in the event that a future design value for 
the area exceeds the level of the ozone standard, or if the fourth-
highest monitored value, averaged over two years, is 0.071 ppm or 
higher.\14\ In this action, the plan being finalized includes required 
contingency provisions (as was described above) as well as additional 
ozone related measures already approved into the SIP due to prior ozone 
standards (also described earlier in this action).
---------------------------------------------------------------------------

    \14\ The list of potential contingency provisions is provided in 
EGLE's submittal dated January 3, 2022. They include: Adoption of or 
updating of VOC or NOX Reasonable Available Control 
Technology (RACT) rules for existing sources covered by USEPA 
Control Technique Guidelines, Alternative Control Guidelines, or 
other appropriate guidance issued after the 1990 CAA, such as VOC 
RACT for increased methane leak monitoring and repair at oil and gas 
compressor stations, automobile and light-duty truck assembly 
coatings, miscellaneous metal and plastic parts coatings, paper, 
film, and foil coatings, miscellaneous industrial adhesives, or 
industrial cleaning solvents, or NOX RACT for stationary 
internal combustion sources, utility boilers, process heaters, iron 
and steel mills, or glass manufacturing; Applying VOC RACT on 
existing smaller sources; Implementing alternative fuel and diesel 
retrofit programs for fleet vehicle Operations; Requiring VOC or 
NOX control on new minor sources (less than 100 tons per 
year); Increasing the VOC or NOX emission offsets for new 
and modified major sources; Reducing idling programs; Trip reduction 
programs; Traffic flow and transit improvements; Working with the 
Michigan Department of Licensing and Regulatory Affairs to encourage 
natural gas utilities to increase turnover of legacy distribution 
pipelines; Stationary engine controls to reduce formaldehyde and 
NOX Emissions; Phase 2 AIM rules; Phase 5 Consumer 
Products rules; and additional measures as identified by EGLE.
---------------------------------------------------------------------------

    For all these reasons, there is no information to support a 
conclusion that EGLE's implementation of this SIP submittal, including 
the maintenance plan now being approved (including contingency 
provisions), would result in an unjustified disparate impact or is 
otherwise prohibited by title VI of the Civil Rights Act. Thus, EPA is 
not requiring any further necessary assurances at this time for 
purposes of compliance with section 110(a)(2)(E)(i).

D. Trend in Design Values

    Comment: The commenters contend that EPA does not have sufficient 
data to determine that the 2021 emission reductions were part of a 
downward trend, as the fourth highest recorded concentration increased 
at all monitor locations except St. Clair County between the years of 
2019 and 2020. As the 2018-2020 design values show nonattainment at 
half of the monitor locations in the area, the commenters contend that 
there is no reason to believe that the 2019-2021 design values will be 
representative of future ozone concentrations.
    Response: Attainment of the 2015 ozone NAAQS, like the 1997 ozone 
NAAQS and 2008 ozone NAAQS before it, is measured by averaging the 
annual fourth-highest daily maximum 8-hour average concentrations over 
a 3-year period. In our rulemaking promulgating the 1997 ozone NAAQS, 
EPA noted the ``lack of year-to-year stability'' inherent to the prior 
1979 ozone NAAQS, and determined that a form including a 3-year average 
would ``provide some insulation from the impacts of extreme 
meteorological events that are conducive to ozone formation.'' (62 FR 
38856, July 18, 1997). Similarly, when EPA revised the NAAQS in 2008, 
we recognized ``that it is important to have a form that is stable and 
insulated from the impacts of extreme meteorological events that are 
conducive to ozone formation. Such instability can have the effect of 
reducing public health protection, because frequent shifting in and out 
of attainment due of meteorological conditions can disrupt an area's 
ongoing implementation plans and associated control programs. Providing 
more stability is one of the reasons that EPA moved to a concentration-
based form in 1997.'' (73 FR 16435, March 27, 2008). In our October 26, 
2015, rulemaking which retained the form of the 1997 ozone NAAQS and 
2008 ozone NAAQS but strengthened the NAAQS to the level of 0.070 ppm, 
EPA found that the three-year average ``provides an appropriate balance 
between public health protection and a stable target for implementing 
programs to improve air quality.'' We therefore observe that as a 
general matter, EPA designed the form of the 2015 ozone NAAQS to 
accommodate some year-to-year variation in ozone concentrations. The

[[Page 32601]]

design value is intended to be the simple average of the annual fourth-
highest daily maximum 8-hour average concentrations over the 3-year 
period, with no special consideration given to any of those three 
years. When we structured the form of the 2015 ozone NAAQS, EPA created 
no requirement that for a monitor or an area to attain the standard, a 
downward trend must be observed within the 3-year period.
    Over a longer period, however, EPA has observed a clear downward 
trend in ozone design values in the Detroit area. In evaluating the 
commenters' claims regarding trends in ozone concentrations, EPA 
reviewed past data from all monitors in the Detroit area. These data 
cover the period ending with the most recent design value period, which 
is 2020-2022, and starting with the design value period that was the 
basis of our nonattainment designation for the 1997 ozone NAAQS, which 
was 2001-2003 (69 FR 56697, September 22, 2004). The historic ozone 
design values for the seven-county Detroit area are summarized in Table 
3. For each 3-year period, the design value is determined by the 
monitor or monitors with the highest 3-year averaged concentration. For 
all 3-year periods, the highest design value was observed at one or 
more of the following five monitors: Port Huron, East 7 Mile, New 
Haven, Allen Park, or Warren.

Table 3--3-Year Average of the Fourth-Highest Daily Maximum 8-Hour Ozone
        Concentrations (Ozone Design Values) for the Detroit Area
------------------------------------------------------------------------
                                                Average fourth-highest
               3-Year period                 daily maximum  8-hour ozone
                                                 concentration (ppm)
------------------------------------------------------------------------
2001-2003..................................                        0.097
2002-2004..................................                        0.092
2003-2005..................................                        0.090
2004-2006..................................                        0.082
2005-2007..................................                        0.086
2006-2008..................................                        0.082
2007-2009..................................                        0.080
2008-2010..................................                        0.075
2009-2011..................................                        0.078
2010-2012..................................                        0.081
2011-2013..................................                        0.077
2012-2014..................................                        0.074
2013-2015..................................                        0.072
2014-2016..................................                        0.073
2015-2017..................................                        0.073
2016-2018..................................                        0.074
2017-2019..................................                        0.072
2018-2020..................................                        0.071
2019-2021..................................                        0.070
2020-2022..................................                        0.070
------------------------------------------------------------------------

    As shown in Table 3, ozone design values in the Detroit area have 
declined significantly from 0.097 ppm in 2001-2003 to 0.070 ppm in 
2019-2021, and 2020-2022. On this point, we agree with the commenters' 
statement that ``there is no doubt that, in general, ozone precursor 
emissions have decreased over the past two decades as noted by the 
studies and that, as a result, ozone concentrations have decreased.'' 
This decrease is clear across the overall time period presented in 
Table 3.
    However, as also shown in Table 3, EPA has sometimes observed an 
increase in ozone design values, such as the increase from 0.073 ppm in 
2015-2017 to 0.074 ppm in 2016-2018. In EPA's view, fluctuation in 
design values over a shorter period does not detract from the overall 
trend in air quality improvements over a longer period. On three 
occasions, at the 2004-2006, 2008-2010, and 2013-2015 3-year periods, 
the design value reached a new low, before experiencing an increase in 
the subsequent 3-year period. However, after each of these occasions, 
the design value returned to its low point within several years and did 
not exceed that low point for a second time. This is consistent with 
national decreasing trends in ozone concentrations which face some 
year-to-year variability in measured concentrations.\15\ Interannual 
variability is expected even when there are longer-term downward trends 
driven by emissions reductions (Strode et al., 2015; \16\ Simon et al., 
2015 \17\). This suggests that, despite variability within a 3-year 
period and occasionally across several 3-year periods, historic 
permanent and enforceable emissions reductions have been effective in 
reducing ozone concentrations in the area, and these reduced ozone 
concentrations have become more durable as the associated control 
programs have progressed through implementation. As we discuss below, 
if a future design value in the Detroit area exceeds the level of the 
2015 ozone NAAQS, then implementation of Michigan's contingency 
provisions, combined with the ongoing implementation of State and 
Federal control measures documented in EGLE's maintenance plan, would 
be the appropriate remedy.
---------------------------------------------------------------------------

    \15\ https://www.epa.gov/air-trends/trends-ozone-adjusted-weather-conditions.
    \16\ Strode, S.A., Rodriguez, J.M., Logan, J.A., Cooper, O.R., 
Witte, J.C., Lamsal, L.N., Damon, M., Van Aartsen, B., Steenrod, 
S.D., and Strahan, S.E.: Trends and variability in surface ozone 
over the United States, J. Geophys. Res.-Atmos., 120, 9020-9042, 
https://doi.org/10.1002/2014JD022784, 2015.
    \17\ Heather Simon, Adam Reff, Benjamin Wells, Jia Xing, and 
Neil Frank, Ozone Trends Across the United States over a Period of 
Decreasing NOX and VOC Emissions, Environmental Science & 
Technology, 2015 49(1), 186-195.
---------------------------------------------------------------------------

E. Timeline

    Comment: The commenters suggest that EPA should wait until the end 
of the 2022 ozone season to act upon the redesignation request.
    Response: EPA is finalizing this action after considering the 
additional year of monitoring data from 2022. In our separate 
rulemaking finalizing a

[[Page 32602]]

clean data determination for the Detroit area, EPA has found that the 
area continued to attain the standard for the 2020-2022 period, which 
is one year beyond the 2019-2021 period which is the basis of the 
State's redesignation request.

F. Meteorology

    Comment: The commenters stated that EPA did not fully consider 
unusually favorable meteorological conditions as the cause for 
decreased ozone concentrations, since EPA relies on temperature studies 
done by EGLE and the Lake Michigan Air Directors Consortium (LADCO) 
that consider long-term ozone concentrations rather than concentrations 
during the design value years. Additionally, the commenters contend 
that although temperature is a large factor in the creation of ozone, 
there are other factors that should be considered. While factors 
besides temperature were considered for the LADCO study, they were only 
considered through 2019 and did not include 2020 or 2021, and the 
commenters stated that the higher 2021 humidity levels could have 
contributed to decreased ozone concentrations. Lastly, the commenters 
also claim that EPA did not account for ``how lower than average 
temperatures and fewer days above 80 degrees Fahrenheit have impacted 
ozone concentrations'' and that ``2019 appears to have been a year with 
exceptionally few high temperature days. In that year, there were only 
76 days with a maximum temperature equal to or above 80 degrees 
Fahrenheit, which is the lowest total since 2009.'' Broadly, the 
commenters question if EGLE and EPA have appropriately considered 
whether temperature and other meteorological conditions, as opposed to 
emissions reductions, were the cause of lower ozone concentrations.
    Response: The analyses of long-term meteorological trends including 
both Michigan's meteorological analysis and LADCO's classification and 
regression tree (CART) analysis helps to illustrate the cause for 
decreasing ozone concentrations over time in the Detroit area. 
Additionally, EPA's Trends in Ozone Adjusted for Weather Conditions 
show that while the Detroit area benefited from unconducive meteorology 
in 2019, the weather adjusted ozone trends show that meteorological 
conditions were more conducive than average in 2020. Thus, the area did 
not experience three consecutive years of unconducive meteorology in 
2019-2021, therefore the meteorology for the 3-year period as a whole 
was not ``unusual''.\18\
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    \18\ https://www.epa.gov/air-trends/trends-ozone-adjusted-weather-conditions.
---------------------------------------------------------------------------

    Michigan's January 3, 2022, submittal presents LADCO's CART 
analysis for years 2005 through 2019, which evaluates 21 separate 
meteorological factors that can influence ozone formation in Detroit. 
This analysis ranks each variable by its relative importance. The most 
important factor in ozone formation in Detroit is Average PM 
Temperature, which is assigned a relative importance level of 1.000. 
Closely following Average PM Temperature are Max Daily Temperature, Max 
Apparent Temperature, and Average AM Temperature which are all assigned 
relatively high variable importance to ozone formation. The last of 
these four, Average AM Temperature, has a relative importance level of 
0.9273. After this variable, there is a steep drop-off before arriving 
at the importance of the fifth variable, which is Average Wind South 
Vector with a relative importance level of 0.5763. In other words, the 
top four variables all relate to temperature, and these temperature 
variables are much more important than any other variable. As shown in 
LADCO's CART analysis for 2005 through 2019, temperature is the peak 
driving meteorological factor determining ozone formation in the 
Detroit area. Additionally, EPA's weather adjusted ozone trends, which 
go through 2021, also have daily max temperature as the most important 
variable at every site in the Detroit area. The next five are PM wind 
direction, AM wind speed, mid-day relative humidity and 24-hour 
transport direction, in varying orders of importance for individual 
ozone sites.
    In evaluating the commenters' concerns that LADCO's CART analysis 
included data only through 2019, EPA reviewed a CART analysis which 
LADCO prepared more recently, and which analyzes data for 2005 through 
2020. Inclusion of the more recent year does not support commenters' 
broader claims regarding meteorological impacts during the design value 
period. Rather, inclusion of the more recent year only reinforces the 
finding that variables relating to temperature are more important than 
any other meteorological variable in determining ozone formation in the 
Detroit area. In the newer analysis, LADCO evaluated a new variable, 
Average Apparent Temperature, which is grouped with the other four 
variables relating to temperature as the most important variables 
affecting ozone formation in Detroit, ahead of the variable for Average 
Wind South Vector and other less-important variables relating to 
factors such as precipitation and humidity.
    Michigan's analysis for the years 2000-2021 considered temperature 
during the ozone season and its relationship with ozone concentrations. 
The State found that ozone concentrations declined over this period, 
even though temperatures increased over the same period. It is 
important to keep in mind that high ozone cannot form in the absence of 
precursor emissions. Michigan's finding is consistent with LADCO's CART 
analysis for the 2005-2019 period in the Detroit area, which shows that 
when the influence of meteorological variability is largely removed, 
ozone concentrations declined regardless, indicating that the downward 
trend in ozone levels is attributable to reductions in precursor 
emissions.
    However, the commenters raise the concern that the State did not 
consider a wider breadth of meteorological factors besides temperature 
in 2020 and 2021. The commenters suggest that there may have been 
unanalyzed unusual meteorological conditions that might have affected 
ozone concentrations. The commenters state that there may have been 
higher levels of humidity in Detroit during the ozone season which may 
have depressed ozone formation in the area. To support this claim, the 
commenters present a graph of Hourly Humidity Comfort Levels 
Categorized by Dew Point for summers 2020 and 2021 in Detroit.\19\ 
However, a presentation of dew point data does not illustrate anything 
useful about humidity levels, because dew point values are a function 
not only of humidity data but also of temperature data. In other words, 
a high dew point value may be caused by high temperatures, even if 
relative humidity is held constant. The commenters also fail to provide 
an analysis of humidity levels for previous years to back up their 
claim that humidity levels in 2020 and 2021 were unusual relative to 
historical levels. Regardless, meteorologically adjusted trends always 
show negative relationships between both relative humidity (RH) and 
ozone and dewpoint and ozone (meaning higher RH and dewpoint are 
associated with lower ozone), while temperature and ozone always have a 
positive relationship (higher temperature is associated with

[[Page 32603]]

higher ozone). As explained above, other meteorological factors had a 
greater influence on Detroit ozone as evidenced by Michigan's, LADCO's 
and EPA's analyses.
---------------------------------------------------------------------------

    \19\ In the narrative section of their comment letter, the 
commenters include the incorrect chart for summer 2021. However, in 
a footnote, the commenters include a URL to the correct chart.
---------------------------------------------------------------------------

    EPA does not agree that we failed to provide significant evidence 
that the improvement in air quality is not attributed to unusual 
meteorological circumstances. EPA relied on Michigan's analysis and the 
LADCO CART analysis to conclude that air quality improvement has been a 
constant trend when meteorology is controlled for variance. The 
commenters have not presented any compelling evidence that the 2019-
2021 design value period had unusual meteorology. Additionally, EPA's 
Trends in Ozone Adjusted for Weather Conditions corroborates these 
analyses.
    As exhibited in LADCO's CART analysis, Detroit has seen decreasing 
ozone concentrations even when controlling for meteorological variance 
between 2005-2019. As presented in Michigan's analysis, ozone 
concentrations have been decreasing between 2000-2021 despite 
increasing temperatures in Detroit. This helps us conclude that the 
long-term trend of decreasing ozone concentrations can be attributed to 
decreases in ozone precursors and not because of meteorological 
factors. Additionally, EPA's Trends in Ozone Adjusted for Weather 
Conditions corroborates these analyses. EPA agrees with Michigan's 
conclusion that the air quality improvement in the Detroit area was 
caused by reductions in ozone precursors and not unusually favorable 
meteorological conditions.

G. Economic Conditions

    Comment: The commenters contend that EPA's determination that 
improved air quality during 2019-2021 was caused by permanent and 
enforceable emissions reductions program has no basis because EPA did 
not fully evaluate whether decreased economic activity from the COVID-
19 pandemic caused improved air quality in the Detroit area. The 
commenters suggest that effects of the COVID-19 pandemic on power plant 
emissions and automobile travel may be the likely cause of the 
reductions rather than the cited enforceable reduction measures. 
Specifically, the commenters raise concerns that reductions in vehicle 
miles traveled and emissions of ozone precursor emissions occurring in 
2020 and 2021 were likely caused by the COVID-19 pandemic. The 
commenters conclude that EPA failed to consider an important aspect of 
the problem in not fully considering the impact of the pandemic in 
EPA's proposed rulemaking to redesignate the Detroit area to attainment 
of the 2015 ozone NAAQS.
    Response: EPA recognizes the difficulties in assessing the impacts 
of the COVID-19 pandemic on ozone precursor emissions and ozone design 
values and the economic disparities from the COVID-19 pandemic, but we 
do not agree that the Detroit area's attainment is due to a temporary 
economic downturn associated with the COVID-19 pandemic. As discussed 
in the March 14, 2022, proposed rulemaking, we think that EGLE's 
submission and the rationale provided in EPA's proposal establishes 
that the area's attainment is due to the cited permanent and 
enforceable reductions and not temporary adverse economic conditions.
    In their January 3, 2022, submittal, EGLE evaluated whether the 
improvement in air quality was caused by temporary adverse economic 
conditions, especially the economic conditions associated with the 
COVID-19 pandemic which first impacted Michigan in 2020. EGLE charted 
point source VOC and NOX emissions in the Detroit area from 
2012 to 2020. These two charts show the overall downward trend in point 
source emissions from 2012 to 2020. EGLE also evaluated both employment 
levels and VMT. While employment levels in the Detroit area were 
affected by COVID-19 and saw a 27 percent decrease in employment from 
March 2020 to April 2020, employment returned to 85 percent of March 
2020 levels by June 2020, according to Bureau of Labor and Statistics 
(BLS) Quarterly Census of Employment and Wages.\20\ Employment levels 
continued to increase through 2022, and as of March 2021 and March 
2022, employment levels in the Detroit area were 93 and 99 percent of 
the employment in February 2020, before the onset of the COVID-19 
pandemic, respectively. As noted by EGLE in their submission, the 
analysis performed by the Southeast Michigan Council of Governments 
(SEMCOG) indicated a reduction of less than 5 percent of VMT in 2020 
based on their travel demand forecasting model.
---------------------------------------------------------------------------

    \20\ See www.bls.gov/cew.
---------------------------------------------------------------------------

    Nevertheless, in response to this comment, EPA has performed 
additional analyses that further support our determination.
    The commenters highlight nationally decreased power plant emissions 
during the COVID-19 pandemic recession beginning in 2020 and cite point 
source reductions that occurred from 2019 to 2020. EPA therefore 
analyzed total heat input from EGUs across the State of Michigan from 
2018 to 2022 to investigate whether Detroit's attainment of the NAAQS 
during the 2020 ozone season could be attributable to economic effects 
from the COVID-19 pandemic.\21\ Of the five years of data examined, our 
analysis found that April 2020 had the single lowest total monthly heat 
input for EGUs located in the seven Southeast Michigan counties in the 
Detroit area. This monthly value is correlated with the strongest 
economic effects that could be attributable to lockdown orders, 
declining employment figures, or decreases in vehicle miles traveled, 
as discussed later in this section. However, we note that the total 
monthly heat input at these power plants began rebounding in May 2020 
and increased to an annual peak in July 2020. This pattern of monthly 
total heat inputs increasing from April onwards and peaking in July or 
August is consistent with annual trends over the five-year period for 
both EGUs in the seven-county Detroit area and across the State as a 
whole. The ozone monitoring season runs from March 1 to September 30 in 
Michigan, but the meteorology most conductive to conditions that could 
result in exceedances of the NAAQS typically occurs in summer months of 
May through July. EPA's analysis shows that while there was a 
pronounced effect on electricity production at EGU facilities in the 
Detroit area in April 2020, emissions activity from these sources 
increased in subsequent months following the same monthly patterns that 
were observed in 2018 and 2019. Moreover, we note similar annual 
patterns of EGU activity peaking in July or August continued again in 
2021 and 2022. Therefore, EPA does not agree that economic effects of 
the COVID-19 pandemic on power plant emissions are responsible for the 
Detroit area's attainment of the NAAQS in 2020 or any year thereafter 
rather than the permanent and enforceable emissions reductions 
described in the notice of proposed redesignation.
---------------------------------------------------------------------------

    \21\ See Appendix B to May 11, 2023, TSD.
---------------------------------------------------------------------------

    In response to the commenters concerns that 2021 emissions were 
still impacted by the pandemic, EPA additionally examined emissions 
from EGUs in Michigan subject to the Cross-State Air Pollution Rule 
NOX Annual Program, and found that there were similar annual 
NOX emissions in 2021 relative to 2019, 31,743 tons per year 
(tpy) versus 31,123 tpy, respectively.\22\

[[Page 32604]]

EPA further evaluated coal consumption for electric power, which the 
commenters note was still lower in 2021 as compared to 2019 likely due 
to the pandemic. Calculations show that 2021 consumption was 97 percent 
of the level of coal consumption in 2019 in Michigan.\23\ In May 2021, 
one of the largest coal-fired EGU facilities in the area, DTE River 
Rouge, permanently retired. The shutdown of this facility was estimated 
by EGLE to achieve annual reductions of 2,716 tons of NOX.
---------------------------------------------------------------------------

    \22\ See Appendix C to May 11, 2023, TSD.
    \23\ See Energy Information Administration, Coal Data Browser 
(Data Set: Total Consumption, Electric Power), https://www.eia.gov/coal/data/browser/.
---------------------------------------------------------------------------

    EPA also analyzed the pandemic's impact on traffic in response to 
the commenters' assertion that automobile travel ``plunged'' in 2020 as 
a result of the pandemic, using data from StreetLight,\24\ which is an 
on-demand mobility analytics platform that uses data from mobile 
devices. We found that traffic did decrease during the pandemic, but 
largely returned to pre-pandemic levels by the time of year that 
meteorological conditions are most conducive to ozone formation. As 
shown in the StreetLight data, the seven-county Detroit area 
experienced a drop in VMT during the period of the stay-at-home order, 
beginning March 23 and ending June 1. However, beginning in June 2020, 
VMT was comparable to VMT levels before the start of the pandemic.\25\ 
This is significant because EPA has found that in the upper Midwest, 
the majority of ozone exceedances occur in late May though late 
July.\26\ In addition, border crossing information, provided by SEMCOG, 
shows that heavy duty truck VMT remained near pre-pandemic levels in 
2020. Given the many mobile source reduction measures in place in 
Michigan, EPA does not conclude that the reductions achieved are based 
on a brief period of decreased VMT in 2020 due to the COVID-19 
pandemic.
---------------------------------------------------------------------------

    \24\ See https://www.streetlightdata.com/. EPA would not rely on 
StreetLight for the purpose of generating inventories, such as the 
inventories submitted by EGLE. However, this data source has a 
reasonable accuracy that is sufficient for the purpose of assessing 
claims made by the commenters regarding temporal changes in VMT 
during the COVID-19 pandemic. EPA believes this source of data is 
usable for this analysis in part because StreetLight data has very 
good performance when compared against traditional manual traffic 
counts, with an R[caret]2 value of 0.9782. StreetLight has been 
utilized by many departments of transportation at the State and 
Federal level. See https://www.streetlightdata.com/transportation-planning-case-studies/.
    \25\ See Appendix D to May 11, 2023, TSD.
    \26\ See Appendix E to May 11, 2023, TSD.
---------------------------------------------------------------------------

    Another important aspect of the economic changes that occurred 
during the COVID-19 pandemic in the Detroit area, which the commenters 
do not address, is that manufacturing processes in the Detroit area did 
not stop during the pandemic, but rather shifted towards new processes 
related to the pandemic. For example, the Oakland County Board of 
Commissioners appropriated over 300,000 dollars to six facilities to 
begin production on personal protection equipment (PPE) such as face 
masks and ventilator equipment.\27\ Ford Motor Company and General 
Motors Corporation (GM) worked to reallocate their production to 
ventilators, which began training by April 2020. GM also began 
producing face masks by March 27, 2020 and worked with a local 
automation company to create an assembly line capable of producing 
50,000 masks a day.\28\ Several nonprofit groups worked to assist 
manufacturing facilities in shifting to production of surgical masks 
and gowns, such as the Industrial Sewing and Innovation Center (ISAIC), 
working with the City of Detroit, Michigan Economic Development 
Corporation, and others to establish efficient and automated production 
methods, noting that this effort was ``a way to keep people employed, 
and at the same time protecting people that are working on the front 
lines.'' \29\ Carhartt worked with ISAIC, and offered one floor of 
their Detroit store to the nonprofit for factory space for this 
initiative, which received funding to produce 1 million surgical masks 
per month. These efforts speak to the rebounding of Detroit's 
employment rates post pandemic and highlight nonprofit work that drove 
much of the initiative to shift production. While the commenters 
highlight the highest single quarterly drop in Gross Domestic Product 
(GDP) of 31.4 percent in the second quarter of 2020, it is important to 
note the highest single quarterly increase in GDP in the third quarter 
of 2020, of 33.1 percent,\30\ noted in the same report by the 
Congressional Research Service. Efforts such as those seen in Detroit 
have likely aided this rebound.
---------------------------------------------------------------------------

    \27\ See https://www.clickondetroit.com/news/local/2020/05/04/oakland-county-funds-manufacturers-to-switch-production-to-medical-equipment-protective-gear.
    \28\ See https://www.assemblymag.com/articles/95741-manufacturers-shift-to-ppe-production-to-fight-covid-19-pandemic.
    \29\ See https://www.modeldmedia.com/features/detroit-apparel-manufacturers-coalition.aspx.
    \30\ See Congressional Research Service, Covid-19 and the U.S. 
Economy, https://crsreports.congress.gov/product/pdf/R/R46606.
---------------------------------------------------------------------------

    EPA does not agree that the Detroit area's attainment is due to a 
temporary economic downturn associated with the COVID-19 pandemic, but 
rather believes the Federally enforceable emission reduction measures 
were the main driving factor in the area coming into attainment.

H. Federal Control Programs

    Comment: The commenters contend that EPA did not demonstrate that 
the Federal good neighbor rules and mobile source standards were key 
elements of the ozone reductions. The commenters assert that most of 
these rules were implemented and would have had emissions impacts prior 
to 2019, and even prior to 2018, and yet ozone concentrations increased 
in 2020 and most of the monitors in the area continued to be in 
nonattainment based on design values for the years 2018-2020. The 
commenters conclude that these facts undermine EPA's finding that the 
reduced ambient concentrations in 2019-2021 are in fact attributable to 
regulations that went into effect from 2004-2017. Additionally, the 
commenters contend that EPA relied on overall pollution reductions from 
the CSAPR Update, which covers areas that are downwind of the Detroit 
area. The commenters point out that EPA did not determine whether 
reductions in emissions specifically causing nonattainment in Southeast 
Michigan will occur, and that, because the CSAPR Update is a cap-and-
trade program, facilities contributing to Detroit's ozone problem could 
comply with the rule by purchasing allowances, rather than reducing 
emissions. The commenters claim that ``reliance on these rules is 
illogical, incomplete, and fails to satisfy the requirements for 
redesignation.''
    Response: Regarding EPA's mobile source standards, the commenters 
have incorrectly interpreted the timeline by which emissions reductions 
are achieved. The full benefit of these programs does not occur in the 
first year that a rule is effective, or even within the years that 
manufacturers must first begin manufacturing vehicles or engines in 
accordance with EPA's rules. These mobile source measures have resulted 
in, and continue to result in, large reductions in NOX 
emissions over time due to fleet turnover (i.e., the replacement of 
older vehicles that predate the standards with newer vehicles that meet 
the standards). Emissions reductions from these programs are modeled by 
EPA's 2016v2 platform and the MOVES3 mobile source emission modeling 
system, which we discuss below in greater detail. In our March 14, 
2022, proposed rulemaking, in our discussions of Tier 3 motor vehicle 
emission standards as well as rules for heavy-duty diesel engines, 
nonroad diesel engines, large

[[Page 32605]]

spark-ignition engines, and marine diesel engines, we noted that some 
of these emission reductions occurred by the attainment years and 
additional emission reductions will occur throughout the maintenance 
period, as older vehicles or engines are replaced with newer, compliant 
model years. It is incorrect that, by pointing out that the Detroit 
area did not attain the standard immediately upon promulgation or 
implementation of these rules, the commenters have demonstrated that it 
is ``illogical'' or ``incomplete'' for EPA to rely on these rules as 
permanent and enforceable emissions reductions as required by CAA 
section 107(d)(3)(E).
    We also disagree that it was ``illogical,'' ``incomplete,'' or 
otherwise inappropriate for EPA to point to emissions reductions 
resulting from the Revised CSAPR Update as contributing to the Detroit 
area's attainment. First, we note that EPA did not only cite the 
Revised CSAPR Update; we also pointed to the historical and/or ongoing 
Federal programs such as the Clean Air Interstate Rule (CAIR), CSAPR, 
CSAPR Update, and Revised CSAPR Update, all of which addressed the 
interstate transport requirements of CAA section 110(a)(2)(D) and 
reduced ozone precursor emissions in the eastern United States over the 
relevant time period.
    First, we note that multiple Federal Circuit Courts of Appeal have 
reviewed similar arguments challenging whether it is reasonable for EPA 
to rely upon regional interstate transport cap-and-trade programs as 
part of the cause of an area's attainment, and those courts have upheld 
EPA's reliance. See Sierra Club v. EPA, 774 F.3d 383 (7th Cir. 2014); 
Sierra Club v. EPA, 793 F.3d 656 (6th Cir. 2015). Arguments raised in 
those cases were remarkably similar to commenters' contentions here: 
``Sierra Club criticizes EPA's reliance on the NOX SIP Call, 
because that program is aimed at reducing pollution in the region as a 
whole and permits the twenty-two affected states to purchase pollution 
`allowances' from one another. Accordingly, Sierra Club believes that 
the effects on any one area in particular are not necessarily permanent 
and enforceable.'' Sierra Club v. EPA, 774 F.3d at 397. The Seventh 
Circuit noted that the overall structure of the trading program ensured 
a regional reduction in emissions, and that ``it is reasonable to rely 
on the program as one basis, among many, for concluding that reduced 
emissions levels will persist.'' Id. at 399. The Sixth Circuit 
similarly upheld challenges to EPA's reliance on interstate transport 
trading programs in a redesignation as one of the causes of an area's 
attainment. Sierra Club v. EPA, 793 F.3d at 665-68.
    While commenters are correct that sources may comply with the 
Revised CSAPR Update by purchasing allowances rather than reducing 
emissions, the Revised CSAPR Update trading region (which includes 
Michigan and is currently comprised of 12 states in the eastern United 
States) is subject to an overall reduction in emissions via the State-
level emissions budgets and assurance levels in that program. 
Commenters are not correct that EPA did not analyze whether reductions 
are and were required from states upwind of Michigan in the Revised 
CSAPR Update. While the Detroit area was not identified as having 
receptors in that rule, emission reductions required of Michigan and 
other states included in the Revised CSAPR Update will still result in 
air quality benefits in the Detroit area, due to the regional nature of 
ozone and ozone precursor transport.
    Further, the control of ozone season NOX emissions under 
the Good Neighbor Provision of the CAA will be continued and improved 
through the more recent final Good Neighbor Plan for the 2015 ozone 
NAAQS, which was signed on March 15, 2023.\31\ This rule, as 
promulgated, is set to control ozone season NOX emissions 
from power plants through a revised trading program beginning in 2023 
and through emissions limits on certain other industrial sources 
beginning in 2026. The initial control stringency for power plants is 
based on the level of reductions achievable through immediately 
available measures, including consistently operating already-installed 
emissions controls. Power plant emissions budgets then decline over 
time based on the level of reductions achievable through phased 
installation of state-of-the-art emissions controls starting in 2024. 
The Good Neighbor Plan covers sources in Michigan, Ohio, Indiana, and 
Illinois, among other states. The final rule includes additional 
features to the trading program for power plants that promote 
consistent operation of emissions controls to enhance public health and 
environmental protection for the affected downwind regions and will 
also benefit local communities, including:
---------------------------------------------------------------------------

    \31\ See https://www.epa.gov/csapr/good-neighbor-plan-2015-ozone-naaqs.
---------------------------------------------------------------------------

     A backstop daily emissions rate in the form of a 3-for-1 
allowance surrender for emissions from large coal-fired units that 
exceed a protective daily NOX emissions rate. This backstop 
would take effect in 2024 for units with existing controls and one year 
after installation for units installing new controls, but no later than 
2030;
     Annually recalibrating the size of the emissions allowance 
bank to maintain strong long-term incentives to reduce NOX 
pollution;
     Annually updating emissions budgets starting in 2030 to 
account for changes in power generation, including new retirements, new 
units, and changing operation. Updating budgets may start as early as 
2026 if the updated budget amount is higher than the State emissions 
budgets established by the final rule for 2026-2029.
    The commenters' concerns about prior NOX cap and trade 
programs are misplaced, and these programs, up through the Revised 
CSAPR Update, can be counted on to deliver ozone air quality benefits. 
We continue to find it reasonable to rely on emissions reductions from 
these programs as one of the measures contributing to the attainment of 
this area. The more recent Good Neighbor Plan for the 2015 ozone NAAQS 
signed in March 2023 builds on these programs and will deliver 
continued assurance that permanent and enforceable emissions reductions 
providing air quality benefits to Detroit (among many other areas) will 
continue to be realized.

I. Maintenance Plan Contingency Provisions

    Comment: The commenters contend that the contingency measure 
triggers in Michigan's maintenance plan are insufficient. The 
commenters conclude that the warning level response trigger of a 1-year 
4th high daily maximum 8-hour average of 74 parts per billion (ppb) and 
the action level response trigger of a 4th high daily maximum 8-hour 
average monitoring value averaged over two years of 71 ppb or more are 
too lenient, and essentially meaningless given the current margin of 
attainment in the area. The commenters note that when considering 
current monitoring data, even a single monitoring value of 71 ppb in 
2022 would result in a violation of the NAAQS and trigger a 
nonattainment designation.
    Response: EPA disagrees with the commenters' contention that the 
contingency measure triggers are inadequate. Under the CAA, a violation 
of the NAAQS subsequent to redesignation to attainment does not trigger 
an automatic redesignation to nonattainment. As demonstrated by the 
contingency provisions requirement in section 175A(d), the CAA clearly 
anticipates and provides for situations where an area might monitor a 
violation

[[Page 32606]]

of the NAAQS after having been redesignated to attainment. Section 
175A(d) of the CAA states that in the event of a NAAQS violation after 
an area is redesignated to attainment a State is required to implement 
additional contingency provisions. Under this section of the CAA, 
states are not obligated to implement additional emission controls if 
an area is ``threatened'' with a future ozone standard violation. 
However, EPA does encourage the states to take preventative measures to 
prevent future ozone standard violations if at all possible, but does 
not definitively require the states to implement the identified 
contingency provisions unless a violation of the standard has actually 
occurred. See September 4, 1992, memorandum from John Calcagni entitled 
``Procedures for Processing Requests to Redesignate Areas to 
Attainment'' (Calcagni memorandum) at 12. Michigan's commitment to 
respond to triggers of a 1-year 4th high daily maximum 8-hour average 
of 74 parts per billion (ppb) and a 4th high daily maximum 8-hour 
average monitoring value averaged over two years of 71 ppb or more in 
addition to responding to a violation of the 2015 ozone NAAQS goes 
beyond the minimum requirements of section 175A(d).
    Comment: The commenters contend that the maintenance plan allows 
Michigan too much discretion in selecting and implementing contingency 
provisions, stating that the language does not commit Michigan to 
implementing any control measures and lacks specificity as to which 
measures should be implemented in response to different levels of 
increasing ozone pollution. The commenters further argue that the 18-
month timeline allowed from the triggering event to implementation of a 
contingency measure is too long, stating that a nonattainment 
designation for the area would be finalized by the time a contingency 
measure is implemented.
    Response: The commenters overlook the provisions of the CAA 
applicable to contingency provisions. Section 175A(d) provides that 
``[e]ach plan revision submitted under this section shall contain such 
contingency provisions as the Administrator deems necessary to assure 
that the State will promptly correct any violation of the standard 
which occurs after the redesignation of the area as an attainment 
area.'' (emphasis added). Thus, Congress gave EPA discretion to 
evaluate and determine the contingency provisions EPA ``deems 
necessary'' to assure that the State will promptly correct any 
subsequent violation. EPA has long exercised this discretion in its 
rulemakings on section 175A contingency provisions in redesignation 
maintenance plans, allowing as contingency provisions commitments to 
adopt and implement in lieu of fully adopted contingency measures, and 
finding that implementation within 18 months of a violation complies 
with the requirements of section 175A. See past redesignations, e.g., 
Columbus, OH 2015 ozone standard (84 FR 43508, August 21, 2019), 
Shoreline Sheboygan County, WI 2008 ozone standard (85 FR 41405, July 
10, 2020), Columbus, OH, 2008 ozone standard (81 FR 93631, December 21, 
2016), Cincinnati, OH-IN, 2008 ozone standard (81 FR 91035, December 
16, 2016, and 82 FR 16940, April 7, 2017), Cleveland, OH 2008 ozone 
standard (82 FR 1603, January 6, 2017), St. Louis, MO-IL 2008 ozone 
standard (83 FR 8756, March 1, 2018), Chicago-Gary-Lake County, IL-IN 
1997 ozone standard (75 FR 26113, May 11, 2010, and 77 FR 48062, August 
13, 2012), Milwaukee-Racine, WI 1997 ozone standard (77 FR 45252, July 
31, 2012), and Detroit-Ann Arbor, MI 1997 ozone standard (74 FR 30950, 
June 29, 2009).
    Section 175A does not establish any specific deadlines for 
implementation of contingency provisions after redesignation to 
attainment. It also provides far more latitude than does section 
172(c)(9), which applies to a different set of contingency measures 
applicable to nonattainment areas. Section 172(c)(9) contingency 
measures must ``take effect . . . without further action by the State 
or [EPA].'' By contrast, section 175A confers upon EPA the discretion 
to determine what constitutes adequate assurance, and thus permits EPA 
to take into account the need of a State to assess, adopt and implement 
contingency provisions if and when a violation occurs after an area's 
redesignation to attainment. Therefore, in accordance with the 
discretion accorded it by statute, EPA may allow reasonable time for 
states to analyze data and address the causes and appropriate means of 
remedying a violation. In assessing what ``promptly'' means in this 
context, EPA also may take into account time for adopting and 
implementation of the appropriate measure. Cf. Greenbaum v. EPA, 370 
F.3d 527, 541 (6th Cir. 2004).
    As discussed in the proposed rule at 87 FR 14218, EPA has 
determined that Michigan's maintenance plan comports with the 
requirements set forth at section 175A of the CAA. The contingency plan 
portion of Michigan's maintenance plan delineates the State's planned 
actions in the event of future 2015 ozone standard violations or 
increasing ozone levels threatening a subsequent violation of the ozone 
standard.
    Michigan has developed a contingency plan with two levels of 
triggered actions. A warning level response is triggered if a 4th high 
daily maximum 8-hour average ozone concentration of 74 ppb or greater 
occurs within the maintenance area. If a warning level response is 
triggered, Michigan will conduct a study to determine whether the ozone 
value indicates a trend toward higher ozone values and whether 
emissions appear to be increasing. The study will evaluate whether the 
trend, if any, is likely to continue and, if so, the control measures 
necessary to reverse the trend. Michigan commits to implementing 
necessary controls within 18 months.
    An action level response is triggered if: (1) a two-year average of 
the 4th high daily maximum 8-hour average ozone concentration at a 
monitor within the maintenance area is 71 ppb or greater; or (2) if a 
violation of the 2015 ozone NAAQS is monitored within the maintenance 
area. If an action level is triggered and is not found to be due to an 
exceptional event,\32\ malfunction, or noncompliance with a permit 
condition or rule requirement,\33\ Michigan will determine what 
additional control measures are needed to assure future attainment of 
the 2015 ozone NAAQS.
---------------------------------------------------------------------------

    \32\ Should Michigan believe an action level response was 
triggered by an exceptional event, Michigan would need to submit an 
exceptional event demonstration in accordance with EPA's Exceptional 
Events Rule codified at 40 CFR 50.1, 50.14, and 51.930. Should EPA 
concur with the demonstration, the event-affected air quality data 
would be excluded from the data set used for certain regulatory 
decisions. Removal of such data would affect the monitoring values 
used to determine whether an action level response was triggered. 
Should EPA non-concur on the exceptional event demonstration or 
should an action level response still be triggered after removal of 
the affected data, Michigan would be required to address the action 
level trigger with control measures sufficient to return the area to 
attainment of the 2015 NAAQS.
    \33\ Should Michigan find that an action level response is 
triggered by malfunction or noncompliance with a permit or rule 
requirement, enforcement action or other measures to ensure an 
expeditious return to compliance may constitute an appropriate 
response to the trigger. Note that depending on the circumstances of 
the trigger, the appropriate response may be a combination of 
compliance assurance and contingency provision implementation.
---------------------------------------------------------------------------

    Michigan's contingency plan for the Detroit area lists a number of 
possible contingency provisions. The list of possible contingency 
provisions in Michigan's plan include the following: (1) VOC or 
NOX RACT rules for existing sources covered by Control 
Technique Guidelines, Alternative Control Guidelines, or other 
appropriate

[[Page 32607]]

guidance; (2) application of VOC RACT on existing smaller sources; (3) 
alternative fuel and diesel retrofit programs for fleet vehicle 
operations; (4) VOC or NOX control on new minor sources 
(less than 100 tons per year); (5) increased VOC or NOX 
emission offsets for new and modified major sources; (6) reduced idling 
programs; (7) trip reduction programs; (8) traffic flow and transit 
improvements; (9) increased turnover of legacy natural gas distribution 
pipelines; (10) stationary engine controls to reduce formaldehyde and 
NOX emissions; (11) phase 2 architectural and industrial 
maintenance coatings (AIM) rules; (12) phase 5 consumer products rules; 
and, (13) additional measures as identified by EGLE. EGLE may also 
consider the timing of an action level trigger and determine if 
additional, significant new regulations not currently included as part 
of the maintenance provisions will be implemented in a timely manner 
and will constitute the response.
    Upon triggering an action level response, Michigan may find that 
choosing a contingency provision from the list included in the 
maintenance plan is not necessary because there are significant new 
regulations already adopted that will address the elevated ozone 
levels. This does not mean that Michigan would be choosing not to 
implement control measures in response to a triggering event. A State 
can choose as its contingency provision any adopted but not fully 
implemented control measure providing that it is not included in the 
calculation of the maintenance inventory. The emissions reductions from 
these programs are real, not considered in maintenance plan emissions 
projections, and can be achieved more quickly since the State has 
already gone through the adoption process. To prohibit a State from 
using any control measure adopted prior to the actual triggering of a 
maintenance plan contingency provision would only penalize states that 
are proactive in addressing anticipated air quality problems.
    Michigan's maintenance plan calls for the appropriate contingency 
provisions to be implemented within 18 months of a triggering event. In 
order to properly deal with potential future ozone standard violations 
and to comply with its own internal rulemaking procedure requirements, 
Michigan requires time to evaluate potential controls and provide 
public notice and public participation in the rulemaking process when 
adopting contingency provisions. The commenters provided no rationale 
for why a time period shorter than 18 months to adopt and implement 
contingency provisions is warranted. EPA finds that 18 months, as 
described in Michigan's maintenance plan, is a reasonable time period 
for Michigan to meet its regulatory obligations while meeting the 
requirement under section 175A to promptly correct a potential 
monitored violation. This timeframe also conforms with EPA's many prior 
rulemakings on acceptable schedules for implementing section 175A 
contingency provisions as noted above.
    Comment: The commenters argue that the maintenance plan should 
address the possibility of a violation of the NAAQS by committing 
Michigan to an expedited nonattainment designation process if that 
occurs.
    Response: Under the CAA, a violation of the NAAQS subsequent to 
redesignation to attainment does not trigger an automatic redesignation 
to nonattainment. As demonstrated by the contingency provisions 
required by section 175A(d), the CAA clearly anticipates and provides 
for situations where an area might monitor a violation of the NAAQS 
after having been redesignated to attainment, and leaves it to the 
Administrator to determine whether redesignation to nonattainment and a 
new nonattainment plan SIP submission is necessary in such cases. 
Michigan's maintenance plan also accounts for this possibility by 
including a violation of the NAAQS as an action level trigger requiring 
the implementation of control measures to reduce ozone precursor 
emissions and bring the area back into attainment. Finally, EPA retains 
its authority under CAA section 107(d)(3)(A) to initiate a 
redesignation ``on the basis of air quality data, planning and control 
considerations, or any other air quality-related considerations the 
Administrator deems appropriate.'' Given this underlying authority, and 
the uncertainty of any cause of a potential future violation, we do not 
agree that it is necessary or appropriate to include the suggested 
commitment in the State's maintenance plan.

J. Maintenance Plan Modeling Platform

    Comment: The commenters argue that because EGLE's 2019 emissions 
inventory shows emissions lower than in EPA's Emissions Inventory 
System, the 2016v2 model that EGLE used may be underpredicting 
emissions, which would impact the future emissions projections.
    Response: The commenters misunderstand how 2016v2 emissions data 
are being used in the context of this redesignation. Air emissions 
modeling platform development is the process of preparing emission 
inventories for use in air quality models. Air quality models typically 
require hourly, gridded emissions of specific pollutants. An emissions 
modeling platform (hereafter referred to as emissions platform or 
platform) is the full set of emissions inventories, other data files, 
software tools, and scripts that process the emissions into the form 
needed for air quality modeling. Each platform relies on a version of 
the NEI for most of its data, although some adjustments are made to 
support air quality modeling. The 2016v2 platform incorporates 
emissions based on: MOVES3, the 2017 NEI nonpoint inventory (both 
anthropogenic and biogenic), the Western Regional Air Partnership oil 
and gas inventory, and updated inventories for Canada and Mexico. The 
2016v2 platform includes emissions for the years 2016, 2023, 2026, and 
2032. Methodologies are documented in the technical support document 
for the 2016v2 platform. The commenters have articulated no specific 
problems with any of the 2016v2 platform emission inventories or with 
the methodologies used to develop them.
    EPA policy, as set forth in the Calcagni memorandum, and 
longstanding practice allows states to demonstrate maintenance by 
preparing an attainment emissions inventory corresponding to the period 
during which the area monitored attainment and to demonstrate 
maintenance by showing that future emissions are projected to remain 
below this level for ten years following redesignation.
    Following this policy, Michigan selected a 2019 emission inventory 
to represent attainment level VOC and NOX emissions, which 
is appropriate because it is one of the years in the period used to 
demonstrate monitored attainment of the NAAQS. In developing the 2019 
attainment inventory for the Detroit area, Michigan interpolated 
between the 2016 and 2023 2016v2 platform inventories for point, 
nonpoint and nonroad inventories. For on-road emissions estimates, 
SEMCOG used EPA's MOVES3 model to generate emissions with local travel 
inputs including vehicle population, VMT, speeds, road types, Vehicle 
Hours of Travel, and vehicle age, as well as meteorological data. To 
demonstrate maintenance through 2035, Michigan developed emission 
inventories for 2035 and an interim year of 2025. To estimate point, 
nonpoint and nonroad emissions, Michigan used 2016v2 platform 
inventories. Specifically, for the 2025 interim year, Michigan 
interpolated between 2023 and 2026 2016v2 platform inventories. For the 
maintenance year, Michigan extrapolated to 2035 using the

[[Page 32608]]

2026 and 2032 2016v2 platform inventories. For on-road emissions in 
2025 and 2035 SEMCOG used EPA's MOVES3 model to generate emissions with 
local travel inputs as described above. When comparing emissions 
between attainment year 2019 and maintenance year 2035, VOC and 
NOX emissions decrease by 34.88 TPSD and 99.55 TPSD, 
respectively. Michigan's maintenance demonstration clearly follows the 
process set forth in the Calcagni memorandum, showing that future 
emissions are projected to decrease and remain below the level of the 
attainment inventory. Again, the commenters articulated no specific 
problems with Michigan's maintenance plan inventories or methodologies 
and suggested nothing specific that should have been done to improve 
those inventories.
    In questioning the validity of these inventories for demonstrating 
maintenance, the commenters pointed to EPA's review of point source 
emissions data submitted through EIS. The commenters mistakenly 
inferred that EPA found all the inventories Michigan submitted based on 
the 2016v2 platform to underestimate emissions in comparison to EIS 
data. This is not the case. In reviewing Michigan's submission, EPA 
only compared the interpolated point source inventories for 2019 
submitted by EGLE against point source emissions information available 
to EPA through EIS. EPA converted annual emission totals to a value of 
tons per ozone season day using the same conversion factors calculated 
by EGLE. Michigan's interpolated inventory estimates 2019 
NOX and VOC point source emissions to be 97.01 tons per 
ozone season day and 13.74 tons per ozone season day, respectively. 
Using EIS reported point source data and conversion factors, EPA 
estimated 2019 NOX and VOC point source emissions to be 
102.27 tons per ozone season day and 29.42 tons per ozone season day, 
respectively. While EIS-based 2019 point source estimates differed from 
estimates based upon interpolation between 2016v2 platform years, 
Michigan's maintenance demonstration remains valid. Regardless of 
whether EGLE had chosen to use point source emissions from EIS or from 
the 2016v2 platform in compiling its inventory for the 2019 attainment 
year, projected emissions for 2025 and future years would be well below 
the attainment inventory, as is demonstrated in Tables 4 and 5. 
Further, beyond making the statement that ``the 2016v2 model may be 
underpredicting emissions,'' the commenters offer no substantive 
evidence to support this conclusion.

   Table 4--Detroit NOX Emissions for 2019 Attainment Year (With EIS and 2016v2 Point Source Emissions), 2025
                                     Interim Year, and 2035 Maintenance Year
                                           [Tons per ozone season day]
----------------------------------------------------------------------------------------------------------------
                                                2019                                    Net change (2019-2035)
                                    ---------------------------                      ---------------------------
              Category                              2016v2         2025       2035                    2016v2
                                     EIS point   interpolated                          EIS point   interpolated
                                       source    point source                           source     point source
----------------------------------------------------------------------------------------------------------------
Point..............................     102.27           97.01       80.8      76.44      -25.83          -20.57
Nonpoint...........................      27.98           27.98      27.39      25.84       -2.14           -2.14
On-road............................     105.80          105.80      61.20      40.30      -65.50          -65.50
Nonroad............................      22.51           22.51      17.49      15.17       -7.34           -7.34
                                    ----------------------------------------------------------------------------
    Total..........................     258.56          253.30     186.91     157.75     -100.81          -95.55
----------------------------------------------------------------------------------------------------------------


   Table 5--Detroit VOC Emissions for 2019 Attainment Year (With EIS and 2016v2 Point Source Emissions), 2025
                                     Interim Year, and 2035 Maintenance Year
                                           [Tons per ozone season day]
----------------------------------------------------------------------------------------------------------------
                                                2019                                    Net change (2019-2035)
                                    ---------------------------                      ---------------------------
              Category                              2016v2         2025       2035                    2016v2
                                     EIS point   interpolated                          EIS point   interpolated
                                       source    point source                           source     point source
----------------------------------------------------------------------------------------------------------------
Point..............................      29.42           13.74       14.1      14.12      -15.30            0.38
Nonpoint...........................     134.77          134.77     134.12     133.11       -1.66           -1.66
On-road............................      51.70           51.70      34.40      22.00      -29.70          -29.70
Nonroad............................      30.46           30.46      27.39      26.56       -3.90           -3.90
                                    ----------------------------------------------------------------------------
    Total..........................     246.35          230.67     209.97     195.79      -50.56          -34.88
----------------------------------------------------------------------------------------------------------------

    Michigan's maintenance plan projected that in 2035, the area would 
see an overall reduction in NOX and VOC emissions of 95.55 
and 34.88 TPSD, relative to the 2019 attainment inventory. More than 
half of these reductions are attributable to the on-road sector with 
projected decreases of 65.50 and 29.70 TPSD in NOX and VOC, 
respectively. The on-road sector was not interpolated or extrapolated. 
It was run using EPA's MOVES3 model and area specific data, which was 
not called into question by the commenters. The difference between 
interpolating point source emissions for 2019 rather than using 
emissions reported through EIS does not change the fact that projected 
emissions for future years 2025 and 2035 are below the level of the 
attainment inventory.
    Comment: The commenters contend that the 2016v2 emissions platform-
based air quality model predictions of ozone concentration decreases 
through 2023 appear overly optimistic, as the majority of the 
reductions would need to occur in the next two years. The commenters 
contend that unrealistic

[[Page 32609]]

predictions by the air quality model render suspect Michigan's reliance 
on the 2016v2 emissions platform for its attainment projections and 
that EPA should explain how it can assure the improvements in air 
quality predicted by the air quality model.
    Response: To clarify, Michigan and EPA are not relying on the air 
quality modeling's predictions (i.e., the projected future design 
values) to meet the CAA's requirement that the maintenance plan provide 
for maintenance of the NAAQS for ten years following redesignation. 
Michigan only used the emissions inventories generated for the 2016v2 
platform and is not relying on the results of the air quality model 
(i.e., the modeled future design values that are estimated using the 
air quality modeling performed using that emissions platform). We do 
not agree that EPA has an obligation to assure the air quality model's 
predicted design values come to pass.
    A maintenance demonstration need not be based on modeling. See Wall 
v. EPA, 265 F.3d 426 (6th Cir. 2001), Sierra Club v. EPA, 375 F. 3d 537 
(7th Cir. 2004). See also 66 FR 53094, 53099-53100 (October 19, 2001), 
and 68 FR 25413, 25430-25432 (May 12, 2003). EPA policy and 
longstanding practice allows states to demonstrate maintenance by 
preparing an attainment emissions inventory corresponding to the period 
during which the area monitored attainment and to project maintenance 
by showing that future emissions are projected to remain below this 
level for the next ten years. See Calcagni memorandum. Holding 
emissions at or below the level of attainment is adequate to reasonably 
assure continued maintenance of the standard. See 65 FR 37879, 37888 
(June 19, 2000).
    Comment: The commenters also express concern that some of the 
regulatory actions assumed in the 2016v2 emissions platform may not be 
implemented in the event of a change in Administration, causing 
emissions to rise.
    Response: As noted above, EPA's longstanding practice is to permit 
states to ``provide for the maintenance of the NAAQS'' as required by 
CAA 175A by comparing current attainment emission inventories with 
projected future inventories. Inherent in the act of projection is some 
uncertainty; in order to accurately project future year inventories, 
the Agency must make assumptions that cannot be made enforceable, such 
as expectations about population growth and energy demand. We would 
also note that, as commenters point out, even adopted, enforceable 
measures can be revised. For the 2016v2 emissions platform, future year 
emissions were projected from the 2016 base case either by running 
models to estimate future year emissions from specific types of sources 
or by adjusting the base year emissions according to the best estimate 
of changes expected to occur in the intervening years. Rules and 
specific legal obligations that go into effect in the intervening 
years, along with anticipated changes in activity of the sector (e.g., 
source retirements) were incorporated when possible. Documentation of 
the specific methodologies used to develop future year emissions for 
the 2016 emissions platform can be found in the technical support 
document for the 2016v2 platform. EPA contends that the methods used to 
develop the 2016v2 emissions platform were appropriate and it was 
reasonable for Michigan to use those emissions in developing 
inventories for the Detroit maintenance plan.

K. Approval of Infrastructure SIP

    Comment: The commenters state that EPA must find that the State 
``has met all requirements applicable to the area for the purposes of 
redesignation under section 110 and part D'' of the CAA, which the 
commenters allege includes having an approved infrastructure SIP 
pursuant to CAA section 110(a)(2). The commenters allege that EPA's 
approval of Michigan's infrastructure SIP for the 2015 ozone NAAQS was 
entered in error, due to an oversight in failing to review and respond 
to comments from Sierra Club. The commenters allege that ``unless and 
until EPA reissues an approval that properly considers and responds to 
this comment, EPA should not consider Michigan to have an approved 
ozone infrastructure SIP for the purposes of redesignation.''
    Response: As we noted in our March 14, 2022, proposed rulemaking, 
SIP requirements that are not linked with the area's ozone designation 
and classification are not ``applicable'' measures to evaluate when 
reviewing a redesignation request for the area under CAA section 
107(d)(3)(E)(ii) and (v). We noted that section 110(a)(2)(D) 
requirements, like many section 110(a)(2) requirements, continue to 
apply to a State regardless of the designation of any one particular 
area within the State, and thus are not applicable requirements for 
purposes of redesignation. See 65 FR 37890 (June 15, 2000), 66 FR 50399 
(October 19, 2001), 68 FR 25418, 25426-27 (May 13, 2003). In addition, 
EPA believes that other section 110 elements that are not connected to 
an area's ozone nonattainment designation are not applicable 
requirements for purposes of redesignation. The area will still be 
subject to these requirements after the area is redesignated to 
attainment of the 2015 ozone NAAQS. This approach is consistent with 
EPA's interpretation of the applicability of conformity requirements 
for purposes of CAA section 107(d)(3)(E)(ii) and (v), as well as with 
section 184 ozone transport requirements. See Reading, Pennsylvania 
proposed and final rulemakings (61 FR 53174-53176, October 10, 1996 and 
62 FR 24826, May 7, 1997), Cleveland-Akron-Loraine, Ohio final 
rulemaking (61 FR 20458, May 7, 1996), and Tampa, Florida final 
rulemaking (60 FR 62748, December 7, 1995). See also the discussion of 
this issue in the Cincinnati, Ohio ozone redesignation (65 FR 37890, 
June 19, 2000), and the Pittsburgh, Pennsylvania ozone redesignation 
(66 FR 50399, October 19, 2001).
    In any case, on May 19, 2022 (87 FR 30420), EPA published a final 
rulemaking which corrected the omission of timely comment and response 
in our September 28, 2021, rulemaking approving most elements and 
disapproving the visibility protection requirements of CAA section 
110(a)(2)(D)(i)(II) prong 4.\34\ EPA has reissued the approval in 
question after responding to comments on the proposal, addressing 
concerns with Michigan's satisfaction of CAA section 110(a)(2)(E)(i) 
with respect to adequate resources.
---------------------------------------------------------------------------

    \34\ Michigan has a partially approved Regional Haze Plan and is 
subject to FIPs for St. Marys Cement, Escanaba Paper Company, and 
Tilden Mining, a taconite processing facility. See 81 FR 21671 
(April 12, 2016) and 83 FR 25375 (July 2, 2018) for more information 
on the FIPs that apply to this area.
---------------------------------------------------------------------------

L. Enforcement Authority

    Comment: The commenters dispute the commitment in Michigan's SIP 
stating that the State ``has the authority to implement the requested 
SIP revision . . . includ[ing] the authority to adopt, implement, and 
enforce any subsequent emission control measures determined to be 
necessary to correct future ozone attainment problems.'' The commenters 
assert that the State does not have the authority to enforce emission 
control measures that may be needed to correct future ozone problems. 
The commenters rely on a decision from the Michigan Court of Claims 
which invalidated a State administrative rule, Michigan Administrative 
Code (MAC) 336.1430 (`Rule 430'), on the basis that the rule failed the 
State Administrative Procedures Act ``general applicability''

[[Page 32610]]

requirement because of its focus on one particular facility. The 
commenters assert that EPA has failed to address the court's holding or 
explain why the Agency believes Michigan will have sufficient authority 
to impose enforceable emissions limitations as may be necessary when a 
particular polluter refuses to limit pollution as needed to bring an 
area into attainment with the NAAQS in the event of future violations 
of the NAAQS that trigger contingency provisions. The commenters urge 
EPA to reexamine whether Michigan has adequate authority to implement 
its maintenance plan in light of U.S. Steel Corp. and to disapprove the 
plan if the Agency concludes that Michigan does not.
    Response: We do not agree that the U.S. Steel Corp. decision 
indicates that Michigan does not have authority to implement and 
enforce its maintenance plan. The State listed the following 
contingency provisions in its maintenance plan for the Detroit area: 
(1) VOC or NOX RACT rules for existing sources covered by 
Control Technique Guidelines, Alternative Control Guidelines, or other 
appropriate guidance; (2) application of VOC RACT on existing smaller 
sources; (3) alternative fuel and diesel retrofit programs for fleet 
vehicle operations; (4) VOC or NOX control on new minor 
sources (less than 100 tons per year); (5) increased VOC or 
NOX emission offsets for new and modified major sources; (6) 
reduced idling programs; (7) trip reduction programs; (8) traffic flow 
and transit improvements; (9) increased turnover of legacy natural gas 
distribution pipelines; (10) stationary engine controls to reduce 
formaldehyde and NOX emissions; (11) phase 2 architectural 
and industrial maintenance coatings (AIM) rules; (12) phase 5 consumer 
products rules; and, (13) additional measures as identified by EGLE. 
Given the nature of these provisions, we think it unlikely that these 
measures are designed to apply only to a single source, like the State 
rule at issue in the U.S. Steel Corp. decision, which the court found 
clearly applied to only one entity and could conceivably apply to only 
one entity. To the extent that the commenters are asserting that EPA 
should disapprove the State's maintenance plan because the State may 
need to target emissions from one particular source in the event of a 
future violation, and the 2017 Court of Claims decision calls into 
question whether the State could do so, we anticipate that the State 
will adopt future measures consistent with the applicable procedural 
State law requirements at issue in U.S. Steel Corp. The State has 
provided in its maintenance plan for twelve contingency provisions that 
on their face appear to be generally applicable, and it would be 
unreasonable to disapprove the SIP submission based on a measure the 
State has not adopted, nor suggested it would adopt, on the speculation 
that such a measure might be necessary.
    Moreover, we note that in our May 19, 2022, final rulemaking 
correcting the omission in the September 28, 2021, rulemaking, EPA 
published a substantive response to Sierra Club's comment regarding 
Michigan's authority to enforce control measures. 87 FR 30420. As we 
noted then, EPA disagrees with the commenters' concern that the 
Michigan Court of Claims decision in United States Steel Corp. v. Dept. 
of Environmental Quality, indicates that Michigan lacks legal authority 
to regulate sources. EPA concluded that the court only decided that the 
State had improperly sought to impose emissions controls on the sources 
at issue through a rule that did not meet State law requirements for a 
``rule of general applicability'' in violation of relevant State 
administrative procedures act requirements. EPA interprets the ruling 
to indicate that the State does have authority under Michigan law to 
impose necessary emission limitations on sources, as required to meet 
CAA requirements, via other legal mechanisms. In our May 19, 2022, 
final rulemaking, EPA identified several authorities by which Michigan 
may enforce its SIP.

M. Prevention of Significant Deterioration (PSD) Program

    Comment: The commenters argue that EGLE did not properly implement 
the preconstruction monitoring requirement for several sources subject 
to PSD New Source Review (NSR), and thus the commenters contend that 
CAA section 107(d)(3)(E)(v), which requires that EPA determine the 
State has met all applicable SIP requirements described in CAA section 
110, is not satisfied. The commenters assert that CAA section 110 
includes a requirement to include provisions for the proper 
implementation of programs including PSD NSR. The commenters 
acknowledge that Michigan has adopted provisions meeting CAA 
requirements regarding preconstruction monitoring requirements into its 
SIP, but the commenters allege that the State has failed to properly 
implement those requirements. Specifically, the commenters State that 
Michigan has failed to collect air quality data as required from 
sources with net emissions increases of 100 tpy or more of VOCs or 
NOX. The commenters also call into question the validity of 
the significant monitoring concentrations for ozone established in 40 
CFR part 51 and 40 CFR part 52 based on a D.C. Circuit decision 
regarding Significant Monitoring Concentrations (SMCs) for particulate 
matter, and they state that the ozone SMCs are unlawful and must be 
vacated.
    Response: CAA section 107(d)(3)(E)(v) states that EPA may not 
promulgate a redesignation of a nonattainment area to attainment unless 
``the State containing such area has met all requirements applicable to 
the area under section 7410 [i.e., section 110] of this title and Part 
D of this subchapter.'' Section 110, as it pertains to obligations for 
states, sets forth the required contents of the revisions to a State's 
implementation plan that must be adopted and submitted to EPA after the 
promulgation of a NAAQS. EPA therefore understands its role in 
determining whether CAA section 107(d)(3)(E)(v) is satisfied to be an 
inquiry into whether a State has adopted and submitted to EPA all those 
revisions to its SIP that are required by section 110 and part D. In 
this case, Michigan has met its obligations to submit those 
requirements applicable to it for purposes of redesignation.
    As we noted in the March 14, 2022, proposed rulemaking, EPA fully 
approved Michigan's PSD program on March 25, 2010 (75 FR 14352), and 
most recently approved revisions to Michigan's PSD program on May 12, 
2021 (86 FR 25954). The SIP-approved PSD program prohibits air quality 
from deteriorating beyond the concentration allowed by the applicable 
NAAQS. See MAC R 336.2811.
    We do not agree with the commenter that a State's implementation of 
its SIP is equivalent to whether the State has met the requirements of 
CAA section 110 and part D, which concern whether a State has made 
required revisions to its SIP. Any issues with respect to the State's 
application of the approved SIP are beyond the scope of this action and 
should be raised on a permit specific basis.
    Similarly, comments regarding the lawfulness of EPA's PSD 
regulations pertaining to ozone at 40 CFR 51.166(i)(5)(i)(f) or 40 CFR 
52.21(i)(5)(i)(f) are outside the scope of this action.

N. Supplemental Comments

    Comment: In their March 14, 2023, supplemental comment, commenters 
contend that EPA cannot redesignate the

[[Page 32611]]

Detroit area until EPA has approved RACT and reasonably available 
control measures (RACM) for the area. Commenters note that under 
section 107(d)(3)(E), EPA cannot redesignate an area unless (among 
other things) ``the State containing such area has met all requirements 
applicable to the area under section [110] and part D of [title I of 
the Act].'' Effective March 1, 2023, EPA reclassified the Detroit ozone 
nonattainment area as Moderate. This triggered a requirement under 
sections 182(b)(2) and 182(f) of the CAA for Michigan to implement RACT 
for sources of VOCs and NOX. The commenters, citing Sierra 
Club v. U.S. EPA, 793 F.3d 656 (6th Cir. 2015), contend that section 
172(c)(1) of the CAA requires Michigan to implement RACM, regardless of 
whether the area is attaining the NAAQS.
    The Commenters further contest EPA's position that, for purposes of 
redesignation ``all requirements applicable to the area'' are those 
that were due prior to the State's submittal of a complete 
redesignation request. The commenters cite the decision in Sierra Club 
v. U.S. EPA for the proposition that EPA does not have discretion to 
reinterpret the CAA's unambiguous requirement that nonattainment plans 
for areas in the Moderate category or worse must include RACT/RACM 
requirements. The commenters state, ``Just as EPA cannot excise [RACT/
RACM] from the statutory requirement that a State meet `all' 
requirements applicable to the area, EPA cannot create a wholesale 
exception to the State's requirement to meet `all' requirements 
applicable to a moderate area based on the timing of the State's 
redesignation submission.'' The commenters assert that EPA's approach 
is contrary to the plain meaning of section 107(d)(3)(E)(v) that 
``all'' means all. The commenters argue that the structure and purpose 
of the CAA confirm their interpretation, claiming that EPA's 
interpretation gives states an incentive to submit redesignation 
requests early, regardless of whether the State qualifies at the time 
of submission, in order to evade future requirements.
    The commenters also contend that ``section 107(d)(3)(E) applies not 
only to redesignation requests from a State, but also to EPA's 
redesignation on its own initiative under section 107(d)(3)(A). Given 
this, EPA cannot explain why the submittal date of a redesignation 
request should have any relevance to section 107(d)(3)(E)(v)'s 
requirements.''
    Response: Section 172(c) of the CAA sets forth the basic 
requirements of air quality plans for states with nonattainment areas. 
Subpart 2 of part D, which includes section 182 of the CAA, establishes 
specific requirements for ozone nonattainment areas depending on the 
areas' nonattainment classifications. Detroit was designated as 
nonattainment and classified as Marginal for the 2015 ozone NAAQS, 
effective August 3, 2018. As provided in subpart 2, for Marginal ozone 
nonattainment areas such as the Detroit area, the specific requirements 
of section 182(a) apply in lieu of the attainment planning requirements 
that would otherwise apply under section 172(c), including the 
attainment demonstration and RACM under section 172(c)(1), reasonable 
further progress under section 172(c)(2), and contingency measures 
under section 172(c)(9).
    The only RACT provision applicable to ozone areas classified as 
Marginal is contained in CAA section 182(a)(2)(A), which requires 
states with ozone nonattainment areas that were designated prior to the 
enactment of the 1990 CAA amendments to submit, within six months of 
classification, all rules and corrections to existing VOC RACT rules 
that were required under section 172(b)(3) prior to the 1990 CAA 
amendments. The Detroit 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 and, in any case, Michigan complied with this 
requirement for the Detroit area under the prior 1-hour ozone 
NAAQS.\35\ With respect to RACM, areas classified as Marginal are not 
required to perform a RACM analysis. This is clearly stated in the 2008 
Ozone NAAQS SIP Requirements Rule, ``Note that a RACM analysis is not 
required for Marginal nonattainment areas since an attainment 
demonstration is not required for those areas.'' \36\ EPA retained this 
approach in the Implementation Rule for the 2015 ozone NAAQS, based on 
the rationale and approach articulated in the final 2008 Ozone NAAQS 
SIP Requirements Rule.\37\
---------------------------------------------------------------------------

    \35\ See 60 FR 46182 (September 7, 1994).
    \36\ 80 FR 12264, 12271 (March 6, 2015).
    \37\ 83 FR 62998, 63007-63008 (December 6, 2018).
---------------------------------------------------------------------------

    The Detroit area was reclassified as Moderate under the 2015 ozone 
NAAQS effective March 1, 2023.\38\ As a Moderate area, Detroit became 
subject to the RACT provisions of CAA section 182(b)(2) and RACM 
requirements associated with the attainment demonstration. These 
moderate RACT and RACM plans became due March 1, 2023.
---------------------------------------------------------------------------

    \38\ 88 FR 6633 (February 1, 2023).
---------------------------------------------------------------------------

    CAA section 107(d)(3)(E)(v) provides that the Administrator may not 
promulgate a redesignation of a nonattainment area to attainment 
unless, among other things, ``the State containing such area has met 
all requirements applicable to the area under section 7410 of this 
title and Part D of this subchapter.'' Since the CAA was amended in 
1990, EPA has consistently interpreted the term ``applicable'' in this 
provision not to include those section 110 and part D requirements that 
came due after the submittal of a complete redesignation request. See 
Calcagni memorandum at 4. Specifically, the Calcagni memorandum 
explains that ``When evaluating a redesignation request, Regions should 
not consider whether the State has met requirements that come due under 
the CAA after submittal of a complete redesignation request'' but that 
per CAA section 175A(c), the requirements of part D remain in force and 
effect for the area until such time as it is redesignated. Id., n.3. 
See also Michael Shapiro Memorandum, September 17, 1993.
    As EPA has explained in actions applying this interpretation over 
the past 30 years, reading the CAA in this way balances the reasonable 
expectations of a requesting State and the timing the CAA provides for 
EPA to act on State submissions. See, e.g., 60 FR 12459, 12465-66 
(March 7, 1995) (Redesignation of Detroit-Ann Arbor for the 1979 1-hour 
ozone NAAQS). Per CAA section 107(d)(3)(D), EPA must approve or deny a 
State's request for redesignation within 18 months of receipt of a 
complete redesignation submittal. With respect to SIP submittals 
addressing applicable CAA section 110 and part D requirements, CAA 
section 110(k)(2) requires EPA to act on such submissions within 12 
months of a determination that the submission is complete (i.e., 
maximum 18 months from submission, given the maximum time frame 
provided under CAA section 110(k) for statutorily deeming a submission 
complete). In order for EPA to approve a redesignation request, per the 
requirements of CAA section 107(d)(3)(E)(ii) it needs to have fully 
approved (per 110(k)) the ``applicable'' implementation plan, which 
again is defined by the ``applicable'' requirements for redesignation 
as set forth in CAA section 107(d)(3)(D)(v). Therefore, if EPA were to 
read the CAA as commenters suggest, by withholding any approval of a 
redesignation until the State made submissions for deadlines

[[Page 32612]]

occurring after the original date of submittal, and until EPA had acted 
on those submissions, the State might never be able to have the area 
redesignated. Each CAA requirement coming due during the pendency of 
EPA's review of a redesignation request carries with it a necessary 
implication that EPA must also fully approve the SIP submission made to 
satisfy that requirement in order for the area to be redesignated. We 
do not think it is a reasonable reading of the CAA to require states to 
make additional SIP submissions on which EPA would need to fully act 
before it could act on the redesignation request before it; such an 
interpretation would almost necessarily delay action on the 
redesignation request beyond the 18-month time frame. EPA's 
interpretation in no way obviates the ongoing obligation of states to 
continue to comply with requirements coming due after the submission of 
the redesignation request. It simply means that areas may be 
redesignated even though the State may not have complied with those 
requirements. See 60 FR at 12466.
    Reviewing courts have upheld EPA's interpretation that requirements 
coming due after a complete redesignation request is submitted are not 
``applicable'' for purposes of redesignation. Sierra Club v. EPA, 375 
F.3d 537 (7th Cir. 2004) (upholding the redesignation of St. Louis 
based on the timing of submittal and deadline of requirements, even 
though by the time EPA acted on the State's redesignation it had been 
reclassified to a higher classification and was subject to more 
stringent SIP requirements, 68 FR 25418, 25424-27 (May 12, 2003)).
    EPA disagrees with the commenters' assertion that this longstanding 
approach is contrary to the plain meaning of section 107(d)(3)(E)(v). 
Commenters emphasize that ``all means all'' but in doing so, they 
excise ``applicable'' from CAA section 107(d)(3)(E)(v). States must 
meet ``all requirements applicable,'' and EPA's 30-year interpretation 
of that phrase is that not every requirement is necessarily applicable 
for purposes of evaluating a redesignation request. EPA further 
disagrees with the commenters' assertion that this longstanding 
interpretation is inconsistent with the Sixth Circuit Court's decision 
in Sierra Club v. U.S. EPA, 793 F.3d 656 (2015). In that case, the CAA 
section 172(c)(1) RACT/RACM requirements at issue had come due prior to 
submission of a complete redesignation request. Moreover, even in the 
2015 Sierra Club decision, the 6th Circuit acknowledged that it had 
previously held that CAA section 107(d)(3)(E)(v) ``could be read to 
`limit the number of actual requirements within [CAA section 110] and 
Part D that apply to a given area,' '' quoting Wall v. EPA, 265 F.3d 
426, 439 (2001), and noting that it had deferred to the Agency's view 
that part D transportation conformity requirements were not 
``requirements applicable to the area'' under CAA section 
107(d)(3)(E)(v). Sierra Club v. EPA, 793 F.3d at 669.
    When Michigan submitted the redesignation request, on January 3, 
2022, the Detroit area was classified as Marginal. As a Marginal area, 
Detroit had no applicable RACT or RACM requirements. The RACT and RACM 
requirements triggered by the reclassification of the Detroit area as 
Moderate did not become due until March 1, 2023, well after Michigan 
submitted a complete redesignation request for the Detroit area. Thus, 
per EPA's interpretation provided above, the Moderate RACT and RACM 
requirements are not ``requirements applicable to the area'' for 
purposes of CAA section 107(d)(3)(E)(v), and EPA is not barred from 
approving the redesignation in the absence of the State having met 
those requirements. EPA determined that Michigan's redesignation 
request was complete for purposes of redesignation because at the time 
it was submitted the Detroit area was attaining the 2015 ozone NAAQS 
and Michigan had submitted all applicable SIP requirements for purposes 
of redesignation. The redesignation request continues to be complete 
because the area has not violated the NAAQS since the redesignation 
request was submitted. Contrary to what was implied by the commenters, 
the State did not submit the redesignation request before the area 
qualified for redesignation. Had Michigan failed to submit all SIP 
requirements applicable for redesignation or failed to demonstrate that 
the Detroit area was attaining the NAAQS, the submission would not have 
been considered complete for purposes of redesignation. Hence there is 
no incentive for states to submit a redesignation request before an 
area qualifies for redesignation.
    Finally, we do not agree that commenters' observations that CAA 
section 107(d)(3)(E) applies also to redesignations initiated by EPA 
under CAA section 107(d)(3)(A) is relevant to which requirements should 
be considered ``applicable'' for purposes of CAA section 
107(d)(3)(E)(v). The CAA contemplates that EPA-initiated redesignations 
under subsection (A) will be followed by response and submission from 
the State. See CAA section 107(d)(3)(B) and (C). While subsection (C) 
contemplates that the Administrator can promulgate some redesignations 
even in the absence of a State submission, other requirements in CAA 
section 107(d)(3)(E) suggest that states must play a key role for 
redesignations from nonattainment to attainment; in particular, the 
requirement under CAA section 107(d)(3)(E)(iv) that a maintenance plan 
be fully approved, because such plan would need to be prepared and 
submitted by a State. Other redesignations, such as redesignations from 
attainment or unclassifiable to nonattainment, are not subject to CAA 
section 107(d)(3)(E), and can therefore be promulgated without any 
submission from the State, as suggested by CAA section 107(d)(3)(C).
    Comment: In their March 14, 2023, supplemental comment, commenters 
raise several additional issues. First, commenters contend that EPA's 
redesignation action was ``constructively reopened for comment'' given 
commenters' contention that EPA ``did not finalize its proposed 
redesignation based on the 2019-2021 data'' and 2022 monitoring data is 
``a critical component of the 2020-2022 design value.'' Second, 
commenters reference EGLE's January 3, 2023, exceptional events 
demonstration for the East 7 Mile monitor, and state that ``they do not 
believe EGLE has adequately supported its exceptional event 
demonstration to meet the high evidentiary standard required to exclude 
the maximum daily 8-hour ozone average.'' The commenters suggest 
instead that ozone concentrations at the monitor may be affected by the 
Stellantis auto assembly complex. Third, commenters reference the 
requirement at CAA section 107(d)(E)(3)(iii) that EGLE must demonstrate 
that improvement in air quality is due to permanent and enforceable 
reductions in emissions, and claim that EGLE must complete such an 
analysis for 2022. Lastly, commenters reference Executive Order 12898, 
and claim that finalizing this redesignation without providing an 
opportunity for public comment on 2022 data would violate EPA policy 
regarding providing fair treatment and meaningful involvement of all 
people. Commenters also claim the weight-of-evidence analysis 
underlying EPA's concurrence determination on an exceptional events 
demonstration is ``inherently biased against environmental justice 
communities.''
    Response: Many of the commenters' contentions are based on a 
misunderstanding of EPA's consideration of 2022 data within this

[[Page 32613]]

final action. EPA is finalizing our March 14, 2022, proposed approval 
of EGLE's January 3, 2022, request to redesignate the Detroit area 
based on attaining monitoring data for 2019-2021, and EPA's 
determination that the area meets all other requirements for 
redesignation at CAA section 107(d)(3)(E). As noted above, EPA's 
determination under CAA section 107(d)(3)(E)(i) also relies on our 
final action on EPA's concurrence of a January 26, 2023, demonstration 
submitted by EGLE, as well as preliminary monitoring data, which 
together show the area has continued to attain the standard subsequent 
to the 2019-2021 period. Contrary to the commenters' contention that 
EGLE must demonstrate that attainment in 2020-2022 was due to permanent 
and enforceable measures, EPA's determination under CAA section 
107(d)(3)(E)(iii) is based only on the 2019-2021 period. EPA also 
disagrees that the redesignation action was ``constructively reopened 
for comment'' given that EPA's determination is based on the 2019-2021 
period and continued attainment since that period, and not based on the 
2020-2022 design value.
    Although this redesignation is related to EPA's Clean Data 
Determination based on 2020 to 2022 data, regarding the data set used 
for regulatory purposes, EPA clearly and properly proposed that action 
and responded to public comments in that final rulemaking. Further, EPA 
conducted extensive public outreach during that public comment period, 
including notification of interest groups before publication of the 
proposed action in the Federal Register, creation of a public-facing 
website including fact sheets, and translation of materials into Arabic 
and Spanish.\39\ EPA disagrees that further public involvement is 
required in order for EPA to take final action. Public notice and 
opportunity to comment were provided consistent with applicable 
requirements, and further information about additional engagement is 
offered earlier in this RTC.
---------------------------------------------------------------------------

    \39\ https://www.epa.gov/mi/detroit-clean-data-determination-2015-ozone-air-quality-standard.
---------------------------------------------------------------------------

    Regarding commenters' claims that the weight-of-evidence approach 
of an exceptional events demonstration is ``inherently biased against 
environmental justice communities,'' the claim that EGLE's 
demonstration did not ``meet the high evidentiary standard,'' or the 
claim that emissions may be affected by the Stellantis facility, EPA 
already addressed substantially similar comments in a separate final 
rulemaking, and these comments have no further relevance to this 
action.

V. Final Actions

    EPA is determining that the Detroit nonattainment area is attaining 
the 2015 ozone NAAQS, based on quality-assured and certified monitoring 
data for 2019-2021. EPA is also approving, as a revision to the 
Michigan SIP, the State's maintenance plan for the area. The 
maintenance plan is designed to keep the Detroit area in attainment of 
the 2015 ozone NAAQS through 2035. EPA is also determining that the 
area meets the requirements for redesignation under section 
107(d)(3)(E) of the CAA. EPA is thus changing the legal designation of 
the Detroit area from nonattainment to attainment for the 2015 ozone 
NAAQS. Finally, EPA is finding adequate and approving the newly 
established 2025 and 2035 motor vehicle emissions budgets. 
Specifically, EPA is finding adequate and approving the budgets for 
2025 (i.e., an interim year) and 2035 (i.e., the last year of the 
maintenance plan) as proposed. The 2025 budgets are 47.86 TPSD of VOCs 
and 104.35 TPSD of NOX and the 2035 budgets are 44.67 TPSD 
of VOCs and 102.41 TPSD of NOX including the assigned safety 
margins.
    In accordance with 5 U.S.C. 553(d) of the Administrative Procedure 
Act (APA), EPA finds there is good cause for this action to become 
effective immediately upon publication. The immediate effective date 
for this action is authorized under 5 U.S.C. 553(d)(1).
    Section 553(d)(1) of the APA provides that final rules shall not 
become effective until 30 days after publication in the Federal 
Register ``except . . . a substantive rule which grants or recognizes 
an exemption or relieves a restriction.'' The purpose of this provision 
is to ``give affected parties a reasonable time to adjust their 
behavior before the final rule takes effect.'' Omnipoint Corp. v. Fed. 
Commc'n Comm'n, 78 F.3d 620, 630 (D.C. Cir. 1996); see also United 
States v. Gavrilovic, 551 F.2d 1099, 1104 (8th Cir. 1977) (quoting 
legislative history). However, when the agency grants or recognizes an 
exemption or relieves a restriction, affected parties do not need a 
reasonable time to adjust because the effect is not adverse. EPA has 
determined that this rule relieves a restriction because this rule 
relieves sources in the area of Nonattainment NSR permitting 
requirements; instead, upon the effective date of this action, sources 
will be subject to less restrictive PSD permitting requirements. For 
this reason, EPA finds good cause under 5 U.S.C. 553(d)(1) for this 
action to become effective on the date of publication of this action.

VI. 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 CAA and applicable Federal regulations. 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. 
Accordingly, this action merely approves State law as meeting Federal 
requirements and does not impose additional requirements beyond those 
imposed by State law.

A. Executive Order 12866: Regulatory Planning and Review, Executive 
Order 13563: Improving Regulation and Regulatory Review, and Executive 
Order 14094: Modernizing Regulatory Review

    This action is not a ``significant regulatory action'' under the 
terms of Executive Order 12866 (58 FR 51735, October 4, 1993) and is 
therefore not subject to review under Executive Orders 12866, 13563 (76 
FR 3821, January 21, 2011), and 14094 (88 FR 21879, April 11, 2023).

B. Paperwork Reduction Act

    This rule does not impose an information collection burden under 
the provisions of the Paperwork Reduction Act of 1995 (44 U.S.C. 3501 
et seq.).

C. Regulatory Flexibility Act

    This action merely approves State law as meeting Federal 
requirements and imposes no additional requirements beyond those 
imposed by State law. Accordingly, the Administrator certifies that 
this rule will not have a significant economic impact on a substantial 
number of small entities under the Regulatory Flexibility Act (5 U.S.C. 
601 et seq.).

D. Unfunded Mandates Reform Act (UMRA)

    This action does not contain any unfunded mandate as described in

[[Page 32614]]

UMRA, 2 U.S.C. 1531-1538, and does not significantly or uniquely affect 
small governments. This action does not impose additional requirements 
beyond those imposed by state law. Accordingly, no additional costs to 
State, local, or tribal governments, or to the private sector, will 
result from this action.

E. Executive Order 13132: Federalism

    This action does not have federalism implications. It will not have 
substantial direct effects on the states, on the relationship between 
the national government and the states, or on the distribution of power 
and responsibilities among the various levels of government.

F. Executive Order 13175: Consultation and Coordination With Indian 
Tribal Governments

    Executive Order 13175 (65 FR 67249, November 9, 2000), requires EPA 
to develop an accountable process to ensure ``meaningful and timely 
input by tribal officials in the development of regulatory policies 
that have tribal implications.'' This rule does not have tribal 
implications, as specified in Executive Order 13175. It will not have 
substantial direct effects on tribal governments. Thus, Executive Order 
13175 does not apply to this rule.

G. Executive Order 13045: Protection of Children From Environmental 
Health and Safety Risks

    EPA interprets Executive Order 13045 as applying only to those 
regulatory actions that concern environmental health or safety risks 
that EPA has reason to believe may disproportionately affect children, 
per the definition of ``covered regulatory action'' in section 2-202 of 
the Executive Order. Therefore, this action is not subject to Executive 
Order 13045 because it approves a State action implementing a Federal 
standard.

H. Executive Order 13211: Actions That Significantly Affect Energy 
Supply, Distribution, or Use

    This action is not subject to Executive Order 13211 (66 FR 28355 
(May 22, 2001)), because it is not a significant regulatory action 
under Executive Order 12866.

I. National Technology Transfer Advancement Act

    This rulemaking does not involve technical standards. Therefore, 
EPA is not considering the use of any voluntary consensus standards.

J. Executive Order 12898: Federal Actions To Address Environmental 
Justice in Minority Populations and Low-Income Populations

    Executive Order 12898 (59 FR 7629, February 16, 1994) directs 
Federal agencies, to the greatest extent practicable and permitted by 
law, to make environmental justice part of their mission by identifying 
and addressing, as appropriate, disproportionately high and adverse 
human health or environmental effects of their programs, policies, and 
activities on minority populations (people of color and/or Indigenous 
peoples) and low-income populations.
    EPA believes that the human health or environmental conditions that 
exist prior to this action result in or have the potential to result in 
disproportionate and adverse human health or environmental effects on 
people of color, low-income populations and/or Indigenous peoples. 
Demographic data identifies that the Detroit area includes communities 
that are pollution-burdened and underserved. Further, EPA performed a 
screening-level analysis using EPA's EJSCREEN to identify environmental 
burdens and susceptible populations in communities in the Detroit area.
    EPA believes that this action is not likely to change existing 
disproportionate and adverse effects on people of color, low-income 
populations and/or Indigenous peoples. While EPA recognizes the 
importance of assessing impacts of our actions on potentially 
overburdened communities, approval of Michigan's redesignation request 
for the 2015 ozone NAAQS would not exacerbate existing pollution 
exposure or burdens for populations in the Detroit area.
    As discussed in the Environmental Justice Considerations section 
and Response to Comments section of this preamble, there is no 
information to support a conclusion that EGLE's implementation of its 
2015 ozone SIP, including the maintenance plan now being approved 
(including contingency measures) would result in a disparate impact on 
minority populations (people of color and/or Indigenous peoples) and 
low-income populations.

K. Congressional Review Act

    This action is subject to the Congressional Review Act, and EPA 
will submit a rule report to each House of the Congress and to the 
Comptroller General of the United States. This action is not a ``major 
rule'' as defined by 5 U.S.C. 804(2).

L. Judicial Review

    Under section 307(b)(1) of the CAA, petitions for judicial review 
of this action must be filed in the United States Court of Appeals for 
the appropriate circuit by July 18, 2023. Filing a petition for 
reconsideration by the Administrator of this final rule does not affect 
the finality of this rule for the purposes of judicial review nor does 
it extend the time within which a petition for judicial review may be 
filed, and shall not postpone the effectiveness of such rule or action. 
This action may not be challenged later in proceedings to enforce its 
requirements. See section 307(b)(2).

List of Subjects

40 CFR Part 52

    Environmental protection, Air pollution control, 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.

    Dated: May 12, 2023.
Debra Shore,
Regional Administrator, Region 5.

    For the reasons stated in the preamble, title 40 CFR parts 52 and 
81 are amended as follows:

PART 52--APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS

0
1. The authority citation for part 52 continues to read as follows:

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


0
2. In Sec.  52.1170, the table in paragraph (e) is amended under 
``Maintenance Plans'' by adding an entry for ``Ozone (8-Hour, 2015)'' 
before the entry for ``Particulate matter'' to read as follows:


Sec.  52.1170  Identification of plan.

* * * * *
    (e) * * *

[[Page 32615]]



                       EPA-Approved Michigan Nonregulatory and Quasi-Regulatory Provisions
----------------------------------------------------------------------------------------------------------------
                                        Applicable          State
    Name of nonregulatory SIP          geographic or      submittal     EPA approval date         Comments
            provision               nonattainment area       date
----------------------------------------------------------------------------------------------------------------
 
                                                  * * * * * * *
----------------------------------------------------------------------------------------------------------------
                                                Maintenance Plans
----------------------------------------------------------------------------------------------------------------
Ozone (8-Hour, 2015).............  Detroit area             1/3/2022  5/19/2023, [INSERT
                                    (Livingston,                       FEDERAL REGISTER
                                    Macomb, Monroe,                    CITATION].
                                    Oakland, St. Clair,
                                    Washtenaw, and
                                    Wayne Counties).
 
                                                  * * * * * * *
----------------------------------------------------------------------------------------------------------------

* * * * *

PART 81--DESIGNATION OF AREAS FOR AIR QUALITY PLANNING PURPOSES

0
3. The authority citation for part 81 continues to read as follows:

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


0
4. Section 81.323 is amended by revising the entry for ``Detroit, MI'' 
in the table entitled ``Michigan-2015 8-Hour Ozone NAAQS [Primary and 
Secondary]'' to read as follows:


Sec.  81.323  Michigan.

* * * * *

                                        Michigan--2015 8-Hour Ozone NAAQS
                                             [Primary and secondary]
----------------------------------------------------------------------------------------------------------------
                                             Designation                            Classification
      Designated area \1\      ---------------------------------------------------------------------------------
                                     Date \2\             Type              Date \2\                Type
----------------------------------------------------------------------------------------------------------------
 
                                                  * * * * * * *
Detroit, MI...................  May 19, 2023.....  Attainment.......
    Livingston County.........
    Macomb County.............
    Monroe County.............
    Oakland County............
    St Clair County...........
    Washtenaw County..........
    Wayne County..............
 
----------------------------------------------------------------------------------------------------------------
\1\ Includes any Indian country in each county or area, unless otherwise specified. EPA is not determining the
  boundaries of any area of Indian country in this table, including any area of Indian country located in the
  larger designation area. The inclusion of any Indian country in the designation area is not a determination
  that the State has regulatory authority under the Clean Air Act for such Indian country.
\2\ This date is August 3, 2018, unless otherwise noted.

* * * * *
[FR Doc. 2023-10563 Filed 5-18-23; 8:45 am]
BILLING CODE 6560-50-P


