[Federal Register Volume 86, Number 156 (Tuesday, August 17, 2021)]
[Rules and Regulations]
[Pages 45871-45887]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2021-17214]


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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 52

[EPA-R04-OAR-2019-0618 and EPA-R04-OAR-2019-0619; FRL-8839-02-R4]


Air Plan Approval; TN; Removal of Vehicle I/M Program for the 
Middle Tennessee and Hamilton County Areas

AGENCY: Environmental Protection Agency (EPA).

ACTION: Final rule.

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SUMMARY: The Environmental Protection Agency (EPA) is approving state 
implementation plan (SIP) revisions submitted by the State of 
Tennessee, through the Tennessee Department of Environment and 
Conservation (TDEC), through letters dated February 26, 2020. 
Specifically, EPA is approving the removal of Tennessee's motor vehicle 
inspection and maintenance (I/M) program requirements for Davidson, 
Sumner, Rutherford, Williamson and Wilson Counties in Tennessee (also 
known as the Middle Tennessee Area) and Hamilton County (also known as 
the Chattanooga Area), from the federally-approved SIP. EPA is 
approving the February 26, 2020, SIP revisions to remove the I/M 
program requirements for the aforementioned areas from the federally-
approved SIP because Tennessee's requests are consistent with the Clean 
Air Act (CAA or Act) and applicable regulations.

DATES: This rule is effective on September 16, 2021.

ADDRESSES: EPA has established dockets for these actions under Docket 
Identification No. EPA-R04-OAR-2019-0618 and EPA-R04-OAR-2019-0619 at 
http://www.regulations.gov. All documents in the dockets are listed on 
the www.regulations.gov website. Although listed in the index, some 
information may not be publicly available, i.e., Confidential Business 
Information 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 can either be retrieved 
electronically via www.regulations.gov or in hard copy at the Air 
Regulatory Management Section, Air Planning and Implementation Branch, 
Air and Radiation Division, U.S. Environmental Protection Agency, 
Region 4, 61 Forsyth Street SW, Atlanta, Georgia 30303-8960. EPA 
requests that if at all possible, you contact the person listed in the 
FOR FURTHER INFORMATION CONTACT section to schedule your inspection. 
The Regional Office's official hours of business are Monday through 
Friday 8:30 a.m. to 4:30 p.m., excluding Federal holidays.

FOR FURTHER INFORMATION CONTACT: Lynorae Benjamin, Chief, Air Planning 
and Implementation Branch, Air and Radiation Division, Region 4, U.S. 
Environmental Protection Agency, 61 Forsyth Street SW, Atlanta, Georgia 
30303-8960. The telephone number is (404) 562-9040. Ms. Benjamin can 
also be reached via electronic mail at [email protected].

SUPPLEMENTARY INFORMATION:

I. This Action

    EPA is approving changes to the Tennessee SIP that were provided to 
EPA under cover letters dated February 26, 2020.\1\ Specifically, the 
State requested that Tennessee Air Pollution Control Regulations 
(TAPCR) 1200-03-29 and Davidson County Regulation 8 be removed from the 
Tennessee SIP.\2\ In addition, Tennessee requested that EPA remove the 
requirements for the Middle Tennessee Area 3 4 and Hamilton 
County to implement an I/M program as part of the Early Action Compact 
(EAC) that was approved by EPA into the non-regulatory portion of the 
Tennessee SIP on August 26, 2005. See 70 FR 50199. EPA is approving 
these requests because the SIP revisions are consistent with the CAA, 
including section 110(l).
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    \1\ EPA officially received Tennessee's I/M SIP revisions on 
February 27, 2020.
    \2\ The State's I/M program at TAPCR 1200-03-29 covers Hamilton 
County in addition to Sumner, Rutherford, Williamson and Wilson 
Counties. Throughout this rule, where EPA uses the phrase ``I/M 
program,'' the Agency is referring to the State's I/M program in 
both the Middle Tennessee Area and Hamilton County, and the Davidson 
County I/M program unless otherwise noted.
    \3\ In December 2002, the Middle Tennessee Area entered into 
EPA's EAC program. As part of the EAC for the Middle Tennessee Area, 
the I/M program was identified as an existing control strategy in 
the SIP.
    \4\ Throughout this final rulemaking, unless otherwise noted, 
where the Middle Tennessee Area is referenced EPA is intending for 
this to mean the area covering Davidson, Sumner, Rutherford, 
Williamson and Wilson Counties.
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II. Background

    On May 15, 2018, a Tennessee law was signed that states that ``no

[[Page 45872]]

inspection and maintenance program shall be employed in this state on 
or after the effective date of this act.'' See Tenn. Code Ann. section 
68-201-119. The Tennessee law states that it ``shall take effect [120] 
calendar days following the date on which the [EPA] approves a revised 
state implementation plan. . . .'' See Motor Vehicles--Inspection and 
Inspectors--Air Pollution, 2018 Tennessee Laws Pub. Ch. 953 (H.B. 
1782). Accordingly, Tennessee submitted the February 26, 2020, SIP 
revisions requesting that EPA remove the provisions that implement an 
I/M program for the Middle Tennessee Area and for Hamilton County from 
the Tennessee SIP.\5\
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    \5\ Tenn. Code Ann. section 68-201-119(c) allows Tennessee 
counties to retain local I/M programs under certain conditions. As 
Tennessee is requesting removal of the I/M program from the SIP, 
EPA's analysis in this final rule assumes that no I/M program will 
be implemented in Hamilton County or the Middle Tennessee Area. 
However, this final action does not preclude local I/M programs from 
being retained at a local level outside of the SIP.
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    EPA published notices of proposed rulemaking (NPRMs) on June 8, 
2020, and June 11, 2020, responding to Tennessee's February 26, 2020, 
SIP revisions requesting that EPA approve removal of the I/M program 
from the Tennessee SIP for the Middle Tennessee Area and for Hamilton 
County, respectively. See 85 FR 35037 and 85 FR 35607. The June 8, 
2020, and June 11, 2020, NPRMs (hereinafter referred to as the June 
2020 NPRMs) were based on EPA's proposed findings that the removal of 
the I/M program from the Tennessee SIP for the Middle Tennessee Area 
and for Hamilton County will not interfere with attainment or 
maintenance of any national ambient air quality standards (NAAQS or 
standards) or with any applicable requirements of the CAA. See EPA's 
June 2020 NPRMs. Comments were due on July 8, 2020, and July 13, 2020, 
respectively. Adverse comments were received on the June 2020 NPRMs and 
are addressed in Section IV of this final rulemaking.
    On April 22, 2021, EPA published a supplemental notice of proposed 
rulemaking (hereinafter referred to as the April 2021 SNPRM) to seek 
public comment on the Agency's additional and clarified technical 
rationale related to the proposed approval of Tennessee's February 26, 
2020, SIP revisions. See 86 FR 21248. The April 2021 SNPRM proposed to 
affirm that the Hamilton County and Middle Tennessee areas would 
continue to attain and maintain the NAAQS after removal of the I/M 
program, and to rely on an emissions inventory comparison to inform its 
determination that both areas would continue to attain and maintain the 
ozone and carbon monoxide (CO) NAAQS. See 86 FR 21248. In the April 
2021 SNPRM, EPA further proposed to conclude that the removal of the I/
M program will not interfere with the ability of other states to attain 
and maintain the 2008 ozone NAAQS under the good neighbor provision of 
the CAA and provided additional information related to that conclusion. 
See 86 FR 21248. Comments on the April 2021 SNPRM were due May 24, 
2021. Adverse comments were also received on the April 2021 SNPRM and 
are addressed in Section IV of this final rulemaking.
    As mentioned above, in this action, EPA is responding to adverse 
comments received of the June 2020 NPRMs. See Section IV of this final 
rule. Further, as relevant, EPA is responding to additional comments 
received on the April 2021 SNPRM and is finalizing the removal of the 
I/M program from Tennessee's SIP for the Middle Tennessee Area and for 
Hamilton County. EPA chose to issue one final rulemaking for all three 
proposals. See Section IV of this final rule.

III. Summary of EPA's Analysis

    EPA's CAA section 110(l) non-interference demonstration supporting 
approval of Tennessee's SIP revisions seeking removal of the I/M 
program in Hamilton County and the Middle Tennessee Area focuses on 
ozone (through its precursors nitrogen oxides (NOX) and 
volatile organic compounds (VOC)) and carbon monoxide (CO), the 
criteria pollutants addressed by I/M programs.\6\ I/M programs are not 
designed to address lead and sulfur dioxide (SO2) emissions, 
and nitrogen dioxide (NO2) is captured generally through 
consideration of NOX impacts. While EPA considers 
NOX, VOCs, ammonia, and SO2 as precursors for 
particulate matter (PM), PM formation in Tennessee is dominated by 
emissions of SO2, reacting in the atmosphere to form 
sulfates, and not by emissions of NOX, VOCs, or ammonia. 
However, NOX and VOC increases are considered through the 
analysis for ozone. Although Tennessee is NOX-limited \7\ 
for ozone formation, EPA also evaluated VOC emissions to be 
environmentally conservative in its action.
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    \6\ The total suite of CAA criteria pollutants are ozone 
(through the precursors NOX and VOCs), CO, PM (and its 
precursors--NOX, VOCs, ammonia, and SO2), 
lead, SO2, and NO2.
    \7\ The term ``NOX limited'' means that changes in 
anthropogenic VOC emissions have little effect on ozone formation. 
Control of NOX and VOC are generally considered the most 
important components of an ozone control strategy, and 
NOX and VOC make up the largest controllable contribution 
to ambient ozone formation. However, Tennessee has shown a greater 
sensitivity of ground-level ozone to NOX controls rather 
than VOC controls. This is due to high biogenic VOC emissions 
compared to anthropogenic VOC emissions in Tennessee. Therefore, 
implemented control measures have focused on the control of 
NOX emissions.
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    EPA used an emissions inventory comparison to inform its 
determination of whether Hamilton County and the Middle Tennessee Area 
would continue to attain and maintain the ozone and CO NAAQS after 
removal of the I/M program. As explained in the April 2021 SNPRM, 
Tennessee chose 2022 as the future year for the State's non-
interference demonstrations.\8\ Tennessee's non-interference 
demonstration utilized EPA's Motor Vehicle Emission Simulator (MOVES) 
modeling system, specifically MOVES2014b, to estimate ozone precursor 
emissions for mobile sources--both on-road and non-road. In general, an 
emissions comparison approach is a reasonable and valid approach to 
determining whether an area removing an I/M program can maintain the 
NAAQS and is very similar to the maintenance demonstrations that 
support the redesignations of areas from nonattainment to attainment 
and 10-year maintenance plans that are required for redesignated areas. 
EPA compared future year emissions (following the removal of the I/M 
program) to emissions in a base year with an attaining design value.\9\ 
If the total future year emissions for the relevant pollutant(s)/
precursor(s) are less than the total base year emissions, EPA considers 
that to be a sufficient and reasonable demonstration that the area will 
maintain the NAAQS where the base year emissions are at a level 
sufficient to achieve the NAAQS. EPA is concluding that these analyses, 
as described greater in EPA's April 2021 SNPRM, provide adequate 
support for the conclusion that the removal of the I/M program from 
Hamilton County and the Middle Tennessee Area is consistent with CAA 
section 110(l). CAA section 110(l) demonstrations are case-specific, 
and modeling is not required to

[[Page 45873]]

demonstrate non-interference under these circumstances.
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    \8\ EPA notes that Tennessee did an analysis of emissions 
between 2022 and 2030 without I/M to determine the potential impact 
of mobile emissions. Tennessee's analysis shows that in the Middle 
Tennessee Area emissions decrease by 35 percent for NOX, 
24 percent for VOC, and 30 percent for CO; and that in Hamilton 
County emissions decrease by 45 percent for NOX, 33 
percent for VOC, and 40 percent for CO. This analysis is provided in 
the dockets for this final rulemaking as weight of evidence.
    \9\ Design values are how EPA measures compliance with the 
NAAQS.
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    In the April 2021 SNPRM, EPA clarified that although Tennessee 
included photochemical modeling sensitivity analyses to provide 
additional weight of evidence in its February 26, 2020, SIP revisions, 
and EPA described those analyses in the June 2020 NPRMs, the 
photochemical modeling sensitivity analyses were not required and were 
not intended as the bases for EPA's proposed determinations that 
removal of the I/M program from Hamilton County and the Middle 
Tennessee Area would not interfere with attainment or maintenance of 
the NAAQS or any other applicable CAA requirements. EPA's conclusion 
that these removals satisfy CAA section 110(l) is based on the 
technical analyses summarized above and provided in greater detail in 
EPA's April 2021 SNPRM. See 86 FR 21248.

IV. Responses to Comments

    EPA received numerous comments on the June 2020 NPRMs and the April 
2021 SNPRM.\10\ Two state representatives expressed objection to 
removal of the I/M program while several state representatives 
expressed strong support for removal of the I/M program and urged EPA 
to take quick action. For this response to comments, the comments have 
been grouped into the following categories: (1) Air quality 
improvements/impacts; (2) non-interference demonstration; and (3) 
comments outside the scope of this rulemaking. EPA's responses to 
comments are provided below.
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    \10\ Comments are available on regulations.gov in dockets for 
EPA-R04-OAR-2019-0619 (Hamilton County) and EPA-R04-OAR-2019-0618 
(Middle Tennessee Area). A majority of the comments were received on 
the June 2020 NPRMs.
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A. Responses to Comments Related to Air Quality Improvements/Impacts

    EPA received numerous comments related to air quality and the 
potential impact of removing the I/M program on human health and the 
environment. EPA's evaluation of these comments and responses is 
provided below.
    Comment A1: Several commenters raise concerns regarding how the 
removal of the ``carbon emissions testing program'' will affect the 
health and wellbeing of the general population of Tennessee as well as 
vulnerable populations, elderly, and children. Many of these commenters 
are particularly concerned about those suffering from asthma or 
allergies. Some commenters state that vehicle emissions could cause 
shortness of breath, wheezing, coughing, pulmonary inflammation, and 
lung disease. Other commenters identify vulnerable populations, such as 
those with cardiovascular diseases, diabetes, or COVID-19, who could be 
particularly affected by vehicle emissions.
    Response A1: Hamilton County and the Middle Tennessee Area are in 
compliance with all of EPA's NAAQS. EPA has established NAAQS for six 
of the most common air pollutants--CO, ozone, PM, NO2, lead, 
and SO2--known as ``criteria pollutants.'' Primary NAAQS are 
set to protect public health with an ``adequate margin of safety,'' 
including the health of at-risk groups; \11\ and secondary NAAQS are 
set to protect the public welfare, which includes effects on trees, 
plants, crops, and ecosystems. See CAA sections 108 and 109. Thus, EPA 
evaluates air quality criteria and impacts to public health and welfare 
as part of the comprehensive standard setting process. EPA's final rule 
revising each of the NAAQS includes a thorough explanation of human 
exposure and health risk assessments conducted in support of the 
Agency's review of evidence of exposures on human health effects, as 
well as detailed rationales for EPA's decisions on the relevant 
standards. See, e.g., 80 FR 65291 (October 26, 2015) (containing an 
analysis of the most recent ozone NAAQS).
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    \11\ For example, the rulemaking associated with the 
establishment of the 2015 8-hour ozone NAAQS states that the action 
provides increased protection for children, older adults, and people 
with asthma or other lung diseases, and other at-risk populations 
against an array of adverse health effects that include reduced lung 
function, increased respiratory symptoms and pulmonary inflammation; 
effects that contribute to emergency department visits or hospital 
admissions; and mortality. See, e.g., 80 FR 65292 (October 26, 
2015).
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    As discussed in the April 2021 SNPRM, EPA conducted a technical 
analysis to comply with CAA section 110(l), which determined the 
impacts of removal of the I/M program in Hamilton County and the Middle 
Tennessee Area. EPA's technical analysis concludes that after removal 
of the I/M program, Hamilton County and the Middle Tennessee Area will 
continue to comply with all NAAQS, including the most stringent NAAQS. 
As discussed above, since the NAAQS are set to protect the public 
health and welfare and EPA's technical analysis shows that the areas 
will continue to comply with all of the NAAQS, public health and 
welfare will continue to be protected once the I/M program is removed 
from the Tennessee SIP.
    Comment A2: Several commenters express concern that removing the I/
M program would harm the natural ecology and wildlife of Tennessee. 
Another commenter wrote that removing the I/M program could negatively 
affect food production. Both types of comments imply that removing the 
I/M program would worsen air quality, resulting in problems for the 
surrounding natural environment.
    Response A2: As mentioned in Response A1, EPA has established 
primary and secondary NAAQS to protect human health and the 
environment. Each NAAQS, with the exception of CO, has both a primary 
and secondary NAAQS.\12\ In some cases, the primary and secondary NAAQS 
are set at the same level. Secondary NAAQS provide public welfare 
protection, including protection against decreased visibility and 
damage to animals, crops, vegetation, and buildings.
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    \12\ See https://www.epa.gov/criteria-air-pollutants/naaqs-table.
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    Hamilton County and the Middle Tennessee Area are in compliance 
with all secondary NAAQS. For reasons explained in EPA's June 2020 
NPRMs and April 2021 SNPRM, EPA disagrees that removing the I/M program 
from the Tennessee SIP will cause Hamilton County or the Middle 
Tennessee Area to violate any NAAQS. Tennessee's technical 
demonstrations support EPA's conclusion that the removal of the I/M 
program for both Hamilton County and the Middle Tennessee Area will not 
interfere with attainment or maintenance of the NAAQS or any other 
applicable requirements of the CAA. Further information concerning 
EPA's evaluation of Tennessee's technical demonstrations can be found 
in Response B1. The commenters do not provide any technical information 
to support their position or indicate that interference with 
maintenance of the secondary NAAQS would result upon removal of the I/M 
program in the Middle Tennessee Area or Hamilton County. EPA has 
determined that upon removal of the I/M program, Hamilton County and 
the Middle Tennessee Area will continue to be in compliance with all 
secondary NAAQS, which are set to address the types of welfare concerns 
raised by the commenters.
    Comment A3: A commenter asserts that air quality is getting worse 
in the Middle Tennessee Area and showing a flat trend in ozone design 
values in the Hamilton County region. With respect to the Middle 
Tennessee Area, a commenter claims that while current ozone NAAQS-
related design values are below the standard, recent observations in 
air quality in the Area have shown an upward trend in highest ozone 
concentrations, indicating the reversal

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of improvements resulting from ``existing control programs'' such as 
Tennessee's I/M program. The commenter goes on to explain that 
``[a]dditionally, when comparing monitor-level 4th high ozone [maximum 
daily average (``MDA8'')]\13\ concentrations for receptors in the 
Middle Tennessee region, values that are used by EPA in determining 
ozone attainment and designations, not a single monitor has shown a 
decrease between 2014 and 2018. In fact, of the five monitors in the 
domain, . . . three show no change in 4th high MDA8 concentrations 
between the two years while the other two monitors show an increase of 
up to 3 parts per billion (ppb) in the MDA8 concentration observed.'' 
The commenter also points to an ``upward trend in highest 
concentrations across all monitors, in particular the maximum 
concentration exceeded 0.085 in 2018.'' The commenter also asserts that 
ozone is increasing in the Middle Tennessee Area based on EPA's Air 
Quality Index (AQI) and points to increases in the number of unhealthy 
days for sensitive groups and the maximum AQI value per year.
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    \13\ In its comments regarding the Middle Tennessee Area, the 
commenter appears to use the term ``MDA8'' to refer to the maximum 
8-hour daily average ozone concentration in a given year at a 
monitor.
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    With respect to Hamilton County, the commenter claims that while 
current ozone NAAQS-related design values are below the standard in 
Hamilton County, recent observations in air quality in the ``region'' 
have shown a flat trend in air quality. The commenter goes on to 
explain that, ``[w]hen comparing monitor-level ozone MDA8 \14\ 
concentrations for receptors Hamilton County, Tennessee, values that 
are used by EPA in determining ozone attainment and designations, 
neither monitor has shown air quality improvement between 2015 and 
2018. In fact, . . . both monitors in the domain . . . show no change 
in MDA8 concentrations between the two years with increases in value 
(poorer air quality) in the intermediate years.''
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    \14\ In its comments regarding Hamilton County, the commenter 
appears to use the term ``MDA8'' to refer to the ozone design value 
at a monitor. The design value at a monitor for the 8-hour ozone 
NAAQS is the annual 4th highest daily maximum 8-hour ozone 
concentration averaged over three years.
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    Response A3: As discussed above in Response A1, EPA sets the NAAQS 
at levels protective of public health and welfare. With respect to 
ozone, the most recent 2015 8-hour ozone NAAQS is met if the annual 4th 
highest daily maximum 8-hour ozone concentration, averaged over three 
years, is equal to or less than 70 ppb. See, e.g., 80 FR 65292 (October 
26, 2015) (containing an analysis of the most recent ozone NAAQS). In 
setting this standard, EPA considered all of the components of the 
NAAQS (indicator, averaging time, level, and form) collectively, and 
determined that the standard provided the requisite protection of 
public health and welfare. See id.
    EPA agrees with the commenter that the Middle Tennessee Area and 
Hamilton County are currently attaining all of the ozone NAAQS, 
including the current 2015 8-hour ozone standard. EPA must evaluate 
these SIP revisions for consistency with CAA section 110(l), which 
prohibits the Agency from approving revisions that would interfere with 
any applicable requirement regarding attainment or any other CAA 
requirement. EPA reviews SIP revisions, like removal of the I/M program 
from Tennessee's SIP, to determine whether they meet the applicable 
requirements of the CAA, including section 110(a)(1), which requires 
SIPs to provide for implementation, maintenance, and enforcement of the 
NAAQS. See CAA section 110(k)(2), (3). EPA considers the status of an 
area attaining the NAAQS when EPA evaluates whether a SIP revision will 
interfere with attainment or maintenance of the NAAQS.\15\
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    \15\ Year to year changes in ozone levels result both from 
changes in precursor pollutant emissions and from fluctuations in 
meteorological conditions. This was taken into consideration in the 
development of the NAAQS and resulted in a protective standard that 
is based on a 3-year average of 4th maximums at an individual 
monitor.
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    In response to concerns about increasing ozone concentrations 
raised by the commenter, EPA evaluated the air quality trends in both 
Hamilton County and the Middle Tennessee Area. The results of this 
analysis, discussed in detail in the April 2021 SNPRM, show that while 
both areas have observed yearly variability in measured ozone 
concentrations, there is not a strong increasing or decreasing trend in 
the ozone concentrations in either area since 2013. Both areas, along 
with several other areas in the southeastern United States, measured 
significantly higher ozone concentrations in 2012. These high 
concentrations were primarily the result of meteorological conditions 
that were very conducive to ozone formation (high temperature, low wind 
speed, and moderate relative humidity). Both areas have continued to 
attain the 2008 8-hour ozone NAAQS and the 2015 8-hour ozone NAAQS 
after each standard became effective.\16\ EPA uses a three-year design 
value to determine NAAQS compliance in order to account for the 
inherent yearly variability in ozone concentrations due to variations 
in meteorology, which can impact ozone levels during periods with 
similar emissions levels.
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    \16\ As shown in Table 1, 2014 is one of the years associated 
with attaining design values for the 2008 8-hour ozone NAAQS of 
0.075 parts per million (ppm). The 2008 8-hour ozone NAAQS was the 
applicable NAAQS for the 2015 ozone season. EPA notes that the 2015 
8-hour ozone NAAQS of 0.070 ppm was not in effect until October 1, 
2015, and all design values, beginning with the 2014-2016 design 
value, attained the 2015 8-hour ozone NAAQS.
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    As shown in Table 1 below, the highest design value for the five 
ozone monitors in the Middle Tennessee Area is 72 ppb in 2014 (using 
2012-2014 data), 67 ppb in 2015 (using 2013-2015 data), 67 ppb in 2016 
(using 2014-2016 data), 66 ppb in 2017 (using 2015-2017 data), 67 ppb 
in 2018 (using 2016-2018 data), 66 ppb in 2019 (using 2017-2019 data), 
and 65 ppb in 2020 (using 2018-2020 data). Starting with the 2013-2015 
design values, the Area's design values do not indicate a strong 
increasing or decreasing trend and have remained below the 2015 8-hour 
ozone NAAQS.

                                             Table 1--Middle Tennessee Ozone Monitor Design Values,\***\ ppb
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                                                        Design value  Design value  Design value  Design value  Design value  Design value  Design value
           Monitor name                   County          2012-2014     2013-2015     2014-2016     2015-2017     2016-2018     2017-2019     2018-2020
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East Health/Trinity Lane.........  Davidson...........             *             *            66         ** 65            66            65            64
Percy Priest Dam.................  Davidson...........            70            65            67            64            67            65            65
Hendersonville...................  Sumner.............            72            67            67            66            66            66            65
Fairview Middle School...........  Williamson.........            66            62            61            60            60            60            60
Cedars of Lebanon................  Wilson.............            67            62            64            63             *             *            60
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* No valid design value due to incomplete data. The Cedars of Lebanon site had incomplete data in 2018 because there was an issue following the
  installation of a new monitoring shelter, and TDEC invalidated data collected before the issue was corrected. The East Health/Trinity Lane site had
  incomplete data in 2013.
** In the June 11, 2020, NPRM (85 FR 35607), EPA inadvertently stated that the 2015-2017 Design Value was 66 ppb. The correct value is 65 ppb.

[[Page 45875]]

 
*** The Middle Tennessee Area was in attainment with the most recent effective ozone NAAQS for the entire period. The 2012-2014 and 2013-2015 design
  values were attaining the 2008 8-hour ozone NAAQS of 75 ppb. EPA notes that the 2015 8-hour ozone NAAQS of 70 ppb was not in effect until October 1,
  2015, and all design values after this date attained the 2015 standard.
As shown in Table 2, the highest design value for the two ozone monitors in Hamilton County is 69 ppb in 2014 (using 2012-2014 data), 66 ppb in 2015
  (using 2013-2015 data), 68 ppb in 2016 (using 2014-2016 data), 67 ppb in 2017 (using 2015-2017 data), 66 ppb in 2018 (using 2016-2018 data), 64 ppb in
  2019 (using 2017-2019 data), and 62 ppb in 2020 (using 2018-2020 data). Since the 2013-2015 design values, the Area's design values do not indicate a
  strong increasing or decreasing trend and have remained below the 2015 8-hour ozone NAAQS.


                                                Table 2--Hamilton County Ozone Monitor Design Values, ppb
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                                           Design value    Design value    Design value    Design value    Design value    Design value    Design value
            Monitor Site Name                2012-2014       2013-2015       2014-2016       2015-2017       2016-2018       2017-2019       2018-2020
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Eastside Utility........................              69              66              68              67              66              64              62
Soddy Daisy High School.................              67              64              65              65              64              64              61
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    EPA also evaluated the annual 4th maximum daily maximum 8-hour 
ozone concentrations for each site in both areas (shown in Table 3). As 
discussed above, it is common for monitors to measure annual 
variability in ozone concentrations due to several factors. These 
annual values do not generally indicate a strong increasing or 
decreasing trend at any of the monitors in the Middle Tennessee Area or 
Hamilton County.

               Table 3--Middle Tennessee Area and Hamilton County: Annual 4th Highest Daily Maximum 8-Hour Ozone Concentrations, 2012-2020
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         Monitor Site name                  County            AQS ID       2012     2013     2014     2015     2016     2017     2018     2019     2020
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East Health.......................  Davidson (Middle        47-037-0011       76      (*)       65       67       66       64       68       65       60
                                     Tennessee Area).
Percy Priest Dam..................  Davidson (Middle        47-037-0026      (*)       60       71       64       68       62       71       63       61
                                     Tennessee Area).
Soddy-Daisy High School...........  Hamilton.............   47-065-1011       77       61       64       68       65       64       64       64       57
Eastside Utility..................  Hamilton.............   47-065-4003       77       64       67       68       69       65       64       65       58
Hendersonville....................  Sumner (Middle          47-165-0007       83       68       66       67       68       64       68       66       63
                                     Tennessee Area).
Fairview Middle School............  Williamson (Middle      47-187-0106       74       62       63       61       61       58       63       60       57
                                     Tennessee Area).
Cedars of Lebanon.................  Wilson (Middle          47-189-0103       77       62       64       61       67       61       64       60       58
                                     Tennessee Area).
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* Indicates that a monitor did not meet annual data completeness criteria for a given year

    Finally, for both areas, EPA evaluated the annual number of days 
with monitored exceedances of the 2015 8-hour ozone NAAQS, where the 
daily maximum 8-hour ozone concentration at any monitor in the area 
exceeded 70 ppb. This is equivalent to the number of days with an ozone 
AQI above 100 and the number of days with an AQI category of 
``unhealthy for sensitive groups'' or worse. The results of this 
analysis are shown in Table 4. Similar to the data presented above, 
these values show year to year variability in the ozone concentrations 
in both areas, but neither area shows a strong increasing nor 
decreasing trend in the frequency of days above the 2015 8-hour ozone 
NAAQS.

    Table 4--Middle Tennessee Area and Hamilton County: Annual Count of Days With Daily Maximum 8-Hour Ozone
                                     Concentrations Above 70 ppb, 2012-2020
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              Area                 2012     2013     2014     2015     2016     2017     2018     2019     2020
----------------------------------------------------------------------------------------------------------------
Middle Tennessee...............       31        0        6        1        4        1        6        1        0
Hamilton County................        8        1        1        3        2        2        1        0        0
----------------------------------------------------------------------------------------------------------------
\*\ For consistency, EPA evaluated the number of days above 70 ppb (the level of the 2015 8-hour ozone NAAQS)
  for all years. Note that this standard was not effective until October 1, 2015. Some of the days counted in
  2012-2015 were not exceedances of the 2008 ozone NAAQS of 75 ppb, which was effective at the time this data
  was collected.

    Comment A4: Several commenters assert that air quality will worsen 
by no longer requiring the monitoring of emissions, and therefore the 
I/M program should not be removed. One commenter in reference to the 
Middle Tennessee Area stated that ``[d]ropping the I/M program will 
increase NOX by 478 tons per year and VOC by 593 tons per 
year,'' and asserts that the analysis ``likely underestimates the 
deterioration of air quality that will occur,'' concluding that the 
emissions increases put ``Tennessee at risk of violating the standard 
in the future.'' At least one commenter also implied that removal of 
the I/M program would remove the ambient air monitoring requirements 
for the areas.
    Response A4: There is no evidence that air quality will worsen to 
the point of violating the NAAQS by no longer requiring periodic 
testing of emissions from individual vehicles in Tennessee. It is 
important to note that I/M programs require scheduled testing of a 
vehicle's tailpipe and evaporative emissions to determine the 
effectiveness of existing emission controls on that individual vehicle. 
Emissions controls are not specifically required by I/M programs but 
rather are required for all light-duty vehicles pursuant to EPA's 
vehicle

[[Page 45876]]

emission standards, as discussed further below in this response. I/M 
programs reduce the emissions of certain pollutants (primarily 
NOX, VOC, and CO) by identifying individual vehicles with 
malfunctioning or deteriorated emission control systems and requiring 
the repair of these vehicles to bring them closer to their original 
certification levels. As discussed in the April 2021 SNPRM, the 
projected combined (point, non-point, on-road and non-road) 
NOX, VOC, and CO emissions increases for the 2022 scenarios 
with and without the I/M program will not impact the Areas' attainment 
of the ozone NAAQS given that total emissions of these pollutants in 
2022 without the I/M program will be well under the total emissions in 
2014 and given the current design values for Hamilton County and the 
Middle Tennessee area.
    Further, EPA has promulgated multiple Federal requirements for 
engine and fuel standards to ensure that passenger vehicles are cleaner 
since the 2000s. On February 10, 2000, EPA issued the Tier 2 passenger 
(light duty) vehicle standards. See 65 FR 6698. The standards set 
stringent emissions standards for passenger vehicles, as well as limits 
on the amount of sulfur, a naturally occurring contaminant, in 
gasoline. Limiting sulfur in gasoline allows emissions reduction 
technologies like catalysts to be significantly more effective in 
reducing NOX and other pollutants. Vehicles and their fuels 
continue to be an important contributor to air pollution. EPA in 2014 
issued standards commonly known as Tier 3, 79 FR 23414 (April 28, 
2014), which considered the vehicle and its fuel as an integrated 
system, setting new vehicle emissions standards and a new gasoline 
sulfur standard beginning in 2017. The vehicle emissions standards 
reduce both tailpipe and evaporative emissions from passenger cars, 
light-duty trucks, medium-duty passenger vehicles, and some heavy-duty 
vehicles. The gasoline sulfur standard enables more stringent vehicle 
emissions standards and makes emissions control systems more effective. 
These rules further cut the sulfur content of gasoline. Cleaner fuel 
makes possible the use of new vehicle emission control technologies and 
cuts harmful emissions in existing vehicles. These standards will 
continue to reduce atmospheric levels of ozone (of which NOX 
and VOC are the primary precursors), PM, NO2, and toxic 
pollution. Also, cessation of the I/M program will not yield an 
immediate change in vehicle emissions. The I/M program's benefits will 
continue for a period of time after its cessation, as vehicles 
inspected and/or repaired up until that time would continue to operate 
in a manner that meets the emissions specification of the program.
    EPA also notes that the removal of the I/M program from Tennessee's 
SIP does not remove the ambient air quality monitoring requirements 
that the State must comply with pursuant to 40 CFR part 58. Ambient air 
quality monitoring will continue in these areas without the I/M program 
in Hamilton County and the Middle Tennessee Area.
    Comment A5: Some commenters mention that air quality is poor in 
Hamilton County and the Middle Tennessee Area. Commenters refer to 2018 
and 2019 reports from the American Lung Association (ALA).\17\ One 
commenter states that in the 2019 ALA report, ``Hamilton County 
received a `D' rating, ranking it among the worst counties in Tennessee 
for air quality.'' Other commenters express concern with breathing 
unhealthy air in Nashville, with one commenter stating that in 2019, 
``Nashville plummeted to the bottom of the American Lung Association's 
[ALA's] State of Air report with unhealthy levels of ozone that put 
`citizens at risk for premature death and other health effects. . . .' 
'' Commenters state that ``Tennessee achieved attainment status in 
2017'' but also note that the ALA's ``annual State of Air Report 
indicates air quality across the country is beginning to decline,'' and 
that 4 in 10 Americans are living with unhealthy air. A commenter 
further states that ``Emissions testing is important to ensure 
Tennessee stays in attainment and continues to improve its air 
quality.'' Additionally, a commenter cites to the ALA report to assert 
that--while ozone levels are improving--PM2.5 levels are 
becoming worse, in part due to climate change-driven wildfires. The 
commenters also request that EPA ``allow local governments the ability 
to opt-in to testing and use this tool to protect air quality.''
---------------------------------------------------------------------------

    \17\ Commenters did not provide either ALA report with their 
comments. EPA has retrieved these reports and is providing them in 
the dockets for this final rulemaking.
---------------------------------------------------------------------------

    Response A5: First, EPA notes that Tennessee is meeting all of the 
NAAQS for all areas in the State with one exception, discussed below. 
As further detailed in EPA's June 2020 NPRMs and EPA's April 2021 
SNPRM, air monitoring data for EPA's most recent and stringent health-
based NAAQS demonstrate compliance with these NAAQS in most areas of 
Tennessee, including Hamilton County and the Middle Tennessee Area. 
State and local agencies submit air monitoring data annually, and EPA 
evaluates this data for compliance with the NAAQS.\18\ See 40 CFR part 
58. Tennessee's 2020 data for compliance with the NAAQS was certified 
in April 2021. EPA has a robust process to establish the NAAQS and sets 
the NAAQS at a level requisite to protect human health and the 
environment. Tennessee's compliance with the NAAQS inherently means 
that citizens in such areas are breathing air that is protective of 
human health. Second, EPA notes that ALA uses a different methodology 
in ``grading'' areas than EPA uses in evaluating areas for compliance 
with the NAAQS. See 2019 ALA report pages 51-54 (discussing the 
methodology used by ALA in grading areas). As discussed in Response A3, 
EPA evaluates SIP revisions for compliance with the NAAQS. EPA notes 
that the statement in the ALA report that 4 in 10 Americans are living 
with unhealthy air is not a direct reference to areas in Tennessee. 
With respect to the assertions regarding PM2.5, please see 
response A6, below.
---------------------------------------------------------------------------

    \18\ The State of Tennessee submitted its 2020 data on April 7, 
2021; EPA concurrence was sent on April 9, 2021. Nashville submitted 
its 2020 data on April 19, 2021; EPA concurrence was sent on April 
20, 2021. Chattanooga submitted its 2020 data on April 30, 2021; EPA 
concurrence was sent on April 30, 2021.
---------------------------------------------------------------------------

    With respect to commenters' assertions that the I/M program should 
be maintained to ensure continued compliance with the NAAQS and 
requests that local areas be allowed to opt-in to I/M programs, EPA 
disagrees in part. EPA notes that Tennessee currently implements the I/
M program as part of the State's discretionary measures to attain and 
maintain the NAAQS. CAA section 110(l) provides that the Administrator 
cannot approve a revision of a plan if the revision would interfere 
with any applicable requirement concerning attainment, or any other 
applicable requirement of the CAA. In addition, section 110(k) of the 
CAA requires EPA to approve SIP revisions that meet all applicable CAA 
requirements. As further discussed in the April 2021 SNPRM, EPA has 
determined that section 110(l) requirements have been met because 
removal of the I/M program will not interfere with attainment or 
maintenance of any NAAQS or any other requirement of the CAA. 
Therefore, because EPA has determined that the SIP revisions meet all 
applicable requirements, EPA is approving Tennessee's request to remove 
the I/M program from the SIP. EPA's action to remove the I/M program 
does not preclude the state or local

[[Page 45877]]

government from maintaining an I/M program at the state or local level.
    The one exception where Tennessee's air quality does not meet the 
NAAQS is a portion of Sullivan County, Tennessee, that encompasses the 
Eastman Chemical Plant. In 2013, EPA designated a portion of Sullivan 
County nonattainment for the 2010 1-hour SO2 NAAQS. CAA 
section 191 requires Tennessee to develop a plan to bring the area back 
in attainment with the SO2 NAAQS as expeditiously as 
possible. As noted in the June 2020 NPRMs (85 FR 35037 and 85 FR 35607) 
and the April SNPRM (86 FR 21248), the pollution control systems for 
light-duty gasoline vehicles subject to the I/M program are not 
designed to reduce emissions for SO2; therefore, removing 
the I/M program requirements will not have any impact on ambient 
concentrations of SO2.
    Comment A6: Some commenters assert that removal of Tennessee's I/M 
program would cause greater increases or would exacerbate issues with 
pollutants uninvolved in ozone formation (i.e., pollutants other than 
NOX or VOC). Others worry that removing the I/M program as 
Tennessee grows warmer would result in increased ozone formation. The 
commenters also mention concerns about greater emissions in PM 
pollution, CO, and greenhouse gases (GHGs) (i.e., methane and carbon 
dioxide (CO2)). Some of the commenters that are worried 
about an increase in GHGs have concerns stemming from a general worry 
about climate change. Another commenter expresses concerns about 
increases in emissions in general, but also acknowledges that ozone 
formation in Tennessee appears to be limited by NOX.
    Response A6: With regard to PM emissions, EPA noted in the June 
2020 NPRMs and the April 2021 SNPRM that I/M programs are not designed 
to reduce direct PM emissions. In fact, EPA's state-of-the-science 
Motor Vehicle Emission Simulator modeling system, MOVES, calculates no 
benefit for direct PM emission reductions from an I/M program. In 
addition, EPA notes that, separate and apart from I/M, there may be PM 
emission benefits in future years due to expected fleet turnover and 
continued implementation of EPA's engine and fuel standards. 
Furthermore, PM formation in Tennessee is dominated by sulfates. As 
noted in the June 2020 NPRMs and the April 2021 SNPRM, Hamilton County 
and the Middle Tennessee Area are well in compliance with the PM 
standards.
    As noted in the June 2020 NPRMs and the April 2021 SNPRM, Hamilton 
County and the Middle Tennessee Area are well in compliance with the CO 
standards. In support of its non-interference demonstration and as 
discussed in EPA's June 2020 NPRMs and April SNPRM, Tennessee used the 
MOVES2014b mobile emissions modeling to determine the change in 
emissions for CO resulting from the removal the I/M program in Hamilton 
County and the Middle Tennessee Area. The results show an increase in 
CO emissions of 6.9 percent for Hamilton County, and of 6.1 percent for 
the Middle Tennessee Area for scenarios in 2022 with and without the I/
M program. However, there is a decrease in total CO emissions from all 
source categories from 2014 to 2022. For reasons described in the April 
2021 SNPRM, EPA has concluded the removal of the I/M program from 
Hamilton County and the Middle Tennessee Area is consistent with the 
CAA.
    In terms of ozone, EPA agrees with the commenter that Tennessee is 
NOX limited, making it the precursor of most consideration 
related to potential impacts. As discussed in the April 2021 SNPRM, 
there is a decrease in total NOX emissions from all source 
categories from 2014 to 2022. EPA also notes that the I/M program does 
not have a direct impact on GHGs and is not designed to reduce 
emissions associated with climate change, such as GHGs.
    Comment A7: Some commenters assert that rural and urban areas face 
different issues when it comes to pollution and air quality. In 
particular, commenters are concerned that dropping the I/M program in 
urban areas, which they claimed tend to have significantly more 
emissions, would increase emissions not only for those areas, but also 
for surrounding rural areas, and potentially cause future violations of 
the standard.
    Response A7: EPA agrees that air quality is important. As discussed 
in EPA's June 2020 NPRMs and April 2021 SNPRM, Hamilton County and the 
Middle Tennessee Area are in attainment or maintenance for all criteria 
pollutants. The Agency has provided detailed information showing that 
the monitors in Hamilton County and the Middle Tennessee Area that 
collect complete, quality assured and certified data for recent years 
have design values that are less than the ozone, PM, and CO standards. 
The design values and recently certified data, in combination with the 
emissions inventory analysis, demonstrate that the areas will continue 
to meet the NAAQS, even as population and vehicles increase not only in 
Hamilton County and the Middle Tennessee Area, but statewide. While 
commenters seem to make a distinction between emissions from urban 
areas versus rural areas, the commenters do not provide information to 
indicate that removal of the I/M program in Hamilton County and the 
Middle Tennessee Area will cause a violation of the NAAQS in those 
areas or any surrounding rural areas. As mentioned in Response A4, EPA 
also notes that removal of the I/M program from the Tennessee SIP does 
not impact Federal vehicle and fuel standards that EPA has promulgated 
in separate rulemakings, and such standards will continue to result in 
significant emission reductions from the operation of vehicles, whether 
in rural or urban areas.
    Comment A8: A commenter implies that removal of the I/M program 
will interfere with future visibility at the Great Smoky Mountains 
National Park.
    Response A8: EPA disagrees with the commenter's assertion that 
removal of the I/M program will interfere with visibility at the Great 
Smoky Mountains National Park. Visibility impairment in the Southeast 
is primarily dominated by sulfates. Sulfate particles form in the air 
from SO2 gas. Most of this gas is released from coal-burning 
power plants and other industrial sources, such as smelters, industrial 
boilers, and oil refineries. As discussed in the June 2020 NPRMs and 
the April 2021 SNPRM, the pollution control systems for light-duty 
gasoline vehicles subject to the I/M program are not designed to reduce 
emissions of SO2 or the broader group of sulfates. In 
addition, as discussed in the April 2021 SNPRM, total NOX 
emissions in 2022 without the I/M program are significantly less than 
total NOX emissions in 2014 for the Middle Tennessee Area 
and Hamilton County.\19\ EPA also notes that there are separate CAA 
requirements related to visibility impairment, known as regional haze, 
that all states must comply with. Removal of the I/M program will not 
remove these requirements which are separate and apart from the I/M 
requirements that individual areas may have.
---------------------------------------------------------------------------

    \19\ NOX emissions can convert to visibility 
impairing nitrates in the atmosphere.
---------------------------------------------------------------------------

    Comment A9: Several commenters express concerns about population 
and vehicle growth and the possible impacts on air quality.
    Response A9: As mentioned in more detail in this final rulemaking, 
vehicles are, and continue to become, cleaner because of EPA's engine 
and fuel standards. Although the population may grow and lead to more 
vehicles, new vehicles will be covered by the most

[[Page 45878]]

recent vehicle emissions standards and be operated with gasoline that 
complies with the most recent Federal requirements.
    Comment A10: A commenter states that ``In east Tennessee there is 
no air emissions testing and the air quality is very poor. The 
transportation sector is a major contributor of poor air quality, 
therefore all vehicles must meet the original manufacturers 
specification's and all aftermarket modifications to vehicle exhaust 
and emissions equipment must be made illegal.''
    Response A10: EPA does not agree with the commenter that air 
quality is very poor in east Tennessee. As mentioned in Response A1, 
all areas in Tennessee are in compliance with the NAAQS with the 
exception of a small portion of Sullivan County in the eastern part of 
the State that is designated as nonattainment for the SO2 
NAAQS. Also, EPA does not understand what the commenter means by ``. . 
. no air emissions testing.'' As noted in Response A4, this action does 
not remove the ambient air quality requirements that Tennessee is 
subject to statewide. To the extent that the commenter is referring to 
vehicle emissions testing, EPA notes that, with respect to SIPs, ``each 
State is given wide discretion in formulating its plan,'' so long as 
the revision is consistent with the CAA, including section 110(l). See 
Union Elec. Co. v. EPA, 427 U.S. 246, 250 (1976); see also Alabama 
Envtl. Council v. EPA, 711 F.3d 1277, 1280 (11th Cir. 2013), Sierra 
Club v. EPA, 939 F.3d 649, 673 (5th Cir. 2019), and Alaska Dep't of 
Envtl. Conservation v. EPA, 540 U.S. 461, 470 (2004).
    EPA agrees with the commenter that the transportation sector is an 
important sector for maintaining air quality and, as discussed in 
Response A4, EPA has taken steps to control emissions from the 
transportation sector, such as the Federal vehicle and fuel standards 
that will continue to provide benefits without the implementation of 
the I/M program in Tennessee. EPA also notes that the commenter's 
statements related to vehicle exhaust and emissions equipment are not 
impacted by or within the scope of this rulemaking.
    Comment A11: One commenter suggests that the topography of 
Chattanooga would exacerbate poor air quality if EPA removed the local 
I/M program. Specifically, the Commenter explains that since 
Chattanooga is surrounded by mountains, the city suffers from a ``well-
known inversion effect'' that traps pollutants in it during certain 
times of the year. Another commenter explains that Nashville sits in a 
depression called the ``Nashville or Central Basin,'' which tends to 
cause air to stagnate over the entire area. Both commenters argue that 
these unique geographical features would exacerbate poor air quality if 
EPA removed the I/M program.
    Response A11: EPA disagrees that Hamilton County and the Middle 
Tennessee Area have ``poor air quality,'' as both areas currently meet 
all of the NAAQS, which is explained in more detail in Response A1. EPA 
does not have evidence to indicate that the removal of the I/M program 
from either Hamilton County or the Middle Tennessee Area will 
exacerbate poor air quality because of the unique geographical features 
in each area. While it is important to identify and mitigate vehicles 
that are not properly functioning and as a result may increase 
emissions, most vehicles are not producing increased emissions. Since 
the 2000s, with EPA's promulgation of Federal requirements for engine 
and fuel standards, passenger vehicles are cleaner. See Response A4 for 
more information on the engine and fuel standards.
    Comment A12: A commenter asserts that COVID-19 pandemic has had an 
anomalous impact on air quality improvements in 2020, and indicates 
that removal of the Tennessee I/M program should not be considered 
until after newer trends in air quality are available. The commenter 
cites to three documents to assert that ``lockdown events have reduced 
the population-weighted concentration of nitrogen dioxide 
(NO2) and particulate matter levels by about 60% and 31% 
across multiple countries, with mixed effects on ozone.''
    Response A12: EPA disagrees with the commenter's implication that 
newer trends in air quality would be necessary to make the 
determination on whether removal of the I/M program would interfere 
with attainment or maintenance of the NAAQS in any area as a result of 
removal of the program from the Tennessee SIP. As detailed in EPA's 
April 2021 SNPRM and briefly described in Section III of this final 
rule, EPA used an emissions inventory comparison approach in which 
total emissions in 2014 were compared to total projected emissions in 
2022. EPA's use of projected emissions in 2022 did not consider any 
potential reduction of emissions or improvements in air quality that 
might be sustained through changes in behavior that citizens in 
Hamilton County and the Middle Tennessee Area might have made as a 
result of the COVID-19 pandemic. Additionally, the commenter did not 
provide any information or analysis indicating that consideration of 
2020 air quality improvements would impact the non-interference 
demonstration.
    In EPA's April 2021 SNPRM, for the Middle Tennessee Area, EPA 
explained that the difference in NOX emissions in 2022, with 
and without the I/M program, is 479 tons per year (tpy) for 
NOX and 594 tpy for VOC. However, the total NOX 
emissions in 2022 without the I/M program are 22,420 tpy less than the 
total NOX emissions in 2014, and total VOC emissions in 2022 
without the I/M program are 6,272 tpy less than the total VOC emissions 
in 2014. For CO, the difference in emissions in 2022, with and without 
the I/M program, is 10,368 tpy. However, the total CO emissions without 
the I/M program are 56,466 tpy less than the total CO emissions in 
2014. Even without the I/M program in 2022, emissions of 
NOX, VOC, and CO are projected to decrease by 47.1 percent, 
15.1 percent, and 23.9 percent, respectively, from 2014 levels.
    For Hamilton County, EPA explained in the April 20201 SNPRM that 
the difference in emissions in 2022, with and without the I/M program, 
is 100 tpy for NOX and 146 tpy for VOC. However, the total 
NOX emissions in 2022 without the I/M program are 3,505 tpy 
less than the total NOX emissions in 2014, and the total VOC 
emissions in 2022 without the I/M program are 858 tpy less than the 
total VOC emissions in 2014. For CO, the difference in emissions in 
2022 with and without the I/M program is 2,979 tpy. However, the total 
CO emissions without the I/M program are 10,061 tpy less than the total 
CO emissions in 2014. Even without the I/M program in 2022, emissions 
of NOX, VOC, and CO are expected to decrease by 27.0 
percent, 8.1 percent and 18.7 percent, respectively from 2014 levels.
    In summary, because 2022 total emissions without the I/M program 
are projected to be less than the total 2014 emissions, EPA is 
concluding that removal of the I/M program in Hamilton County and the 
Middle Tennessee Area will not interfere with attainment or maintenance 
of the NAAQS, or any other applicable CAA requirements.\20\ As 
mentioned above and in EPA's April 2021 SNPRM, while EPA considers 
NOX, VOCs, ammonia, and SO2 as precursors for PM, 
PM formation in Tennessee is dominated by emissions of SO2, 
reacting in the atmosphere to form sulfates, and not by emissions of 
NOX, VOCs, or ammonia. However, NOX and VOC 
increases are considered through the analysis for ozone described in 
great

[[Page 45879]]

detail in EPA's April 2021 SNPRM and summarized in this final rule. EPA 
also notes that in the April 2021 SNPRM, the Agency explains that with 
regard to the I/M program, NO2 is captured generally through 
consideration of NOX impacts.
---------------------------------------------------------------------------

    \20\ Meteorology is not used directly for the emissions 
inventory approach that EPA used as the basis of its technical 
analysis.
---------------------------------------------------------------------------

B. Responses to Comments Related to the Non-Interference Demonstration

    EPA received technical comments asserting that the non-interference 
demonstration is inadequate to approve the SIP revisions. EPA's 
evaluation of these comments and responses is provided below.
    Comment B1: In response to EPA's June 2020 NPRMs, a commenter 
asserts that the non-interference demonstrations cannot be considered 
technically complete without air quality modeling to simulate the 
impact of removing the I/M program. The commenter recommends ``a full 
air quality simulation of the impact of removing the I/M program''--
specifically suggesting the use of a transport grid model--to ensure 
that increases in air pollutant concentrations do not exceed NAAQS and 
health-based recommendations. The commenter also recommends that the 
``air quality simulation'' utilize the ``most current modeling platform 
and associated emission projections,'' as well as meteorological and 
base year inventories that meet EPA guidance. The commenter cites EPA 
SIP modeling guidance in support of its recommendations. To further 
support its modeling recommendation, the commenter expresses concerns 
regarding the use of historical trends in air quality and emissions to 
evaluate impacts of I/M program removal due to annual variations in 
meteorology and actual emissions and the need for a solid conceptual 
model of how ozone or PM2.5 is formed in the areas. Also, in 
response to EPA's April 2021 SNPRM, the commenter reasserts its 
position that the non-interference demonstration should be based on air 
quality modeling, asserting that a case-by-case determination by EPA 
that air quality modeling is warranted with respect to the removal of 
the I/M program; the commenter further provides a number of comments 
related to the ozone sensitivity analysis that Tennessee provided in 
its SIP revisions. The commenter does not provide substantive comments 
on EPA's technical non-interference demonstration as provided in the 
April 2021 SNPRM.
    Response B1: EPA does not agree with the commenter that air quality 
modeling is required in order for EPA or the State to assess, pursuant 
to section 110(l) of the CAA, whether removal of the I/M program from 
Tennessee's SIP will interfere with attainment or maintenance of the 
NAAQS or any other requirement of the CAA. EPA acknowledges that air 
quality modeling is an option that could be used to evaluate the impact 
of removal of the I/M program. However, other technical analyses that 
do not involve modeling may also be used for section 110(l) 
demonstrations.
    EPA refers the commenter to EPA's April 2021 SNPRM for more detail 
related to EPA's non-interference analysis. Also, as further explained 
in EPA's June 2020 NPRMs and April 2021 SNPRM, the pollution control 
systems for light-duty gasoline vehicles subject to the I/M program are 
not designed to reduce (and do not reduce) emissions for PM, lead, and 
SO2 in Tennessee.
    For CO and ozone, EPA reviewed Tennessee's MOVES2014b mobile 
modeling which estimated emissions in 2022 with and without the I/M 
program.\21\ Tennessee developed an inventory based on the best 
available information to the State at the time of the submissions for 
both Hamilton County and the Middle Tennessee Area. EPA reviewed the 
inventory with and without the benefit of the I/M program for each 
area. As EPA noted in the June 2020 NPRMs and the April 2021 SNPRM, 
there was a slight increase in NOX and VOC on-road emissions 
for each area for 2022 for the scenarios without the I/M program, as 
compared to the scenarios with the I/M program. For ozone, EPA agrees 
with a commenter's statement that ozone formation in Tennessee is 
NOX-limited (i.e., ozone concentrations are most effectively 
reduced by lowering NOX emissions rather than VOC 
emissions).\22\ Nonetheless, as discussed in the April 2021 SNPRM, EPA 
evaluated both the increases in on-road VOC and NOX to 
determine whether the increase in total emissions in 2022 would 
interfere with attainment or maintenance of the ozone NAAQS in either 
area. EPA's analysis presented in the April 2021 SNPRM demonstrates 
that total emissions in these areas are projected to decrease 
significantly from the 2014 base year to the 2022 future year, even if 
the I/M program is discontinued. The small increase in on-road 
emissions resulting from removal of the I/M program in 2022 are 
overcome by the continued decrease in total emissions, despite 
increases in vehicle miles travelled, due to fleet turnover (i.e., old 
vehicles being replaced with new vehicles that meet more stringent 
engine standards).
---------------------------------------------------------------------------

    \21\ Tennessee chose 2022 as the future year for the State's 
non-interference demonstrations because it is the year when the 
State anticipated that the Areas will cease implementation of the I/
M program due to the CAA's SIP processing timeframe and the language 
of Tenn. Code Ann. section 68-201-119.
    \22\ As part of the Southeastern Modeling and Analysis Planning 
(SEMAP) project, Georgia Institute of Technology performed an 
analysis of the sensitivity of ozone concentrations in the Eastern 
U.S. to reductions in emissions of both NOX and VOC and 
determined that the Southeast is NOX limited. This 
analysis was based off the 2007 and 2018 SEMAP modeling which used 
the Community Multi-scale Air Quality model, version 5.01 with 
updates to the vertical mixing coefficients and land-water 
interface. May 1st through September 30th was modeled using a 12-km 
modeling grid that covered the Eastern U.S.
---------------------------------------------------------------------------

    EPA disagrees with the commenter's concerns regarding the use of 
historical trends in air quality and emissions to evaluate impacts of 
I/M program removal due to annual variations in meteorology and actual 
emissions and the need for a solid conceptual model of how ozone or 
PM2.5 is formed in the areas. EPA acknowledges the 
importance of understanding the factors affecting ozone and 
PM2.5 formation in an area, and Response A6 provides 
information about factors affecting ozone and PM2.5 in 
Tennessee. Concerns about annual variations in meteorology are 
addressed in Response A3. EPA believes that the large decreases in 
emissions of NOX, VOC, and CO described in the April 2021 
SNPRM overshadow the effects of annual variations in actual emissions.
    Although Tennessee included photochemical modeling sensitivity 
analyses to provide additional weight of evidence in its submissions, 
as described by EPA above and in the April 2021 SNPRM, such analyses 
were not required and were not the basis for EPA's proposed 
determinations that removal of the I/M program from Hamilton County and 
the Middle Tennessee Area would not interfere with attainment or 
maintenance of the NAAQS or any other applicable CAA requirements. 
Specifically, in the April 2021 SNPRM, EPA clarified that it was not 
the Agency's intention to rely on Tennessee's ozone sensitivity 
analysis. Thus, any comments related to the sufficiency of that ozone 
sensitivity analysis are not relevant to the actions that EPA are 
finalizing in this document. EPA's conclusion that these removals 
satisfy CAA section 110(l) is based on the technical analysis presented 
in EPA's April 2021 SNPRM.
    Comment B2: With respect to the commenter's concerns on the June 
2020 NPRMs and the April 2021 SNPRM regarding the nonlinearity of ozone 
formation related to Tennessee's sensitivity analysis, the commenter

[[Page 45880]]

reviewed EPA modeling \23\ and ``developed ozone source apportionment 
results and relationships between State-source category specific ozone 
source apportionment modeling and the seasonal NOX emissions 
used to develop the ozone concentrations,'' which, the commenter 
states, ``provide indicators of relative contribution of source regions 
(states) and categories (e.g., motor vehicle) NOX and VOC 
emissions to downwind monitor ozone concentrations.'' The commenter 
asserts that this analysis indicated that ``emissions from motor 
vehicle sources contribute the greatest relative concentration from 
U.S. anthropogenic emissions to the monitors,'' in the areas and 
estimates that localized reductions (in the areas of analysis) would 
have a larger relative impact on ozone concentrations (as compared to 
statewide estimations). The commenter also developed regional ``impact 
factors,'' and asserts that the commenter found (using updated 
emissions, projections, and models) ``that the relative impact of 
NOX emissions from mobile sources in Tennessee have factors 
significantly higher than most other regional-category combinations, 
leading us to conclude that motor vehicle and nonroad source emissions 
have the greatest impact on ozone concentrations'' in the Areas. The 
commenter did not provide the modeling files, just the summary of the 
results in the comments.
---------------------------------------------------------------------------

    \23\ The commenter based their analysis on the Comprehensive Air 
quality Model with eXtensions/Ozone Source Apportionment Technology 
(CAMX/OSAT) modeling platform that EPA prepared for the 
CSAPR Close-Out rule. See 83 FR 65878, 65887-88 (December 21, 2018).
---------------------------------------------------------------------------

    Response B2: As discussed in the April 2021 SNPRM, EPA's analysis 
relies on an emissions inventory comparison to determine whether 
Hamilton County and the Middle Tennessee Area would continue to attain 
the ozone and CO NAAQS after removal of the I/M program. EPA is not 
relying on an ozone sensitivity analysis to determine that removal of 
the I/M program would not interfere with attainment or maintenance of 
the NAAQS. Therefore, the alleged deficiencies related to nonlinearity 
of ozone formation from NOX and VOC precursors in 
Tennessee's sensitivity analyses are irrelevant. As noted in other 
comment responses in this rule, the State has primacy over air quality 
planning and has the authority to determine which source categories to 
control to maintain the NAAQS. Under the CAA, the sole issue for EPA's 
consideration in this rulemaking is whether removing the I/M program 
from the SIP for these two areas would be consistent with CAA 
provisions, including whether discontinuation is expected to interfere 
with attainment and maintenance of air quality standards. As discussed 
further in the April 2021 SNPRM, EPA is approving removal of the I/M 
program from the SIP because removal is consistent with the 
requirements of the CAA, including noninterference with attainment and 
maintenance of the NAAQS.
    Comment B3: In response to EPA's June 2020 NPRMs, a commenter 
asserts that Tennessee's MOVES modeling did not use appropriate 
assumptions, pointing to changes in Federal Corporate Average Fuel 
Economy (CAFE) standards, Reid Vapor Pressure (RVP) standards, and 
biofuel blending requirements that were not included in the model. The 
commenter asserts that EPA must either conduct the modeling itself 
using the appropriate inputs to confirm that there will be no 
interference with the NAAQS or disapprove the non-interference 
demonstration and require the State to do the correct modeling. 
Further, in response to EPA's April 2021 SNPRM, a commenter discusses 
EPA's recent release of MOVES3 and asserts that TDEC should consider 
the impact that the changes in this model have on the assumptions 
included in the removal of the I/M program in the State. The commenter 
further asserts that TDEC should consider this impact ``especially in 
light of EPA's findings that NOX emissions estimates were 
higher in future years in urban areas using MOVES3 compared to 
MOVES2014b.''
    Response B3: EPA disagrees with the commenter. EPA reviewed the 
MOVES2014b modeling that was submitted by Tennessee to support the non-
interference demonstration and concluded that the State used 
appropriate assumptions for the model and performed the modeling in 
accordance with EPA's MOVES Technical Guidance.\24\ Tennessee used the 
MOVES2014b model which was the latest version of the model available at 
the time that the State submitted its SIP revisions, and the State is 
not required to redo its analysis based on the release of an updated 
model after the State's submissions.\25\
---------------------------------------------------------------------------

    \24\ See EPA's July 2014 ``Policy Guidance on the Use of 
MOVES2014 for State Implementation Plan Development, Transportation 
Conformity, and Other Purposes'' (hereinafter MOVES 2014 Guidance). 
This document is available at https://nepis.epa.gov/Exe/ZyPDF.cgi?Dockey=P100K4EB.pdf.
    \25\ EPA released the latest mobile modeling platform, MOVES3, 
on November 16, 2020, approximately nine months after Tennessee 
submitted its SIP revisions, and EPA only recently announced MOVES 
as EPA's official model for future SIP development outside of 
California (January 7, 2021, 86 FR 1106). EPA's November 2020 Policy 
Guidance on the Use of MOVES3 for State Implementation Plan 
Development, Transportation Conformity, General Conformity, and 
Other Purposes (EPA-420-B-20-044) (hereinafter MOVES3 Policy 
Guidance) notes that ``[s]tates should use the latest version of 
MOVES that is available at the time that a SIP is developed.'' This 
document is available at https://www.epa.gov/sites/production/files/2020-11/documents/420b20044_0.pdf. Also, the Guidance states the 
following: ``All states other than California should use MOVES3 for 
SIPs that will be submitted in the future so that they are based on 
the most accurate estimates of emissions possible. However, state 
and local agencies that have already completed significant work on a 
SIP with MOVES2014 (e.g., attainment modeling has already been 
completed with MOVES2014) may continue to rely on the earlier 
version of MOVES.''
---------------------------------------------------------------------------

    Regarding the changes to the CAFE standards, the National Highway 
Traffic Safety Administration has finalized the revisions to the CAFE 
standards for light duty vehicles.\26\ However, that final action does 
not have any impact on Tennessee's demonstration related to removal of 
the I/M program. The vehicles affected by the revised CAFE standards 
would still need to meet applicable criteria pollutant emissions 
standards (e.g., the Tier 3 emissions standards; see 79 FR 23414).
---------------------------------------------------------------------------

    \26\ See ``The Safer Affordable Fuel-Efficient (SAFE) Vehicles 
Rule for Model Years 2021-2026 Passenger Cars and Light Trucks,'' 85 
FR 24174 (April 30, 2020).
---------------------------------------------------------------------------

    Regarding RVP and biofuel blending requirements, EPA reviewed the 
selected fuel formulations (including those for biofuels) for the 
modeled mobile emissions and concurred that they accurately reflect the 
Areas' profiles. The fuel formulation encompasses all the properties 
for that particular fuel (i.e., sulfur levels, benzene, and RVP).
    While the commenter mentions that ``. . . NOX emissions 
estimates were higher in future years in urban areas using MOVES3 
compared to MOVES2014b[,]'' the commenter does not provide any 
information to indicate that NOX emissions in either 
Hamilton County or the Middle Tennessee Area would be higher or would 
interfere with attainment or maintenance of any NAAQS. As detailed in 
EPA's April 2021 SNPRM and summarized above, NOX emissions 
in Hamilton County and the Middle Tennessee Area are estimated to be 
3,505 tpy and 22,420 tpy lower than 2014 emissions, respectively. EPA 
is concluding that it is reasonable to assume that a change to a more 
recent version of MOVES would not result in an increase in emissions 
over the significant decreases in emissions between 2014 and 2022.

[[Page 45881]]

    Comment B4: A commenter raises a number of concerns with regard to 
the sensitivity analysis that was provided as part of the State's non-
interference demonstration. The commenter asserts that the wrong 
inventory was used, stating that Tennessee used the ``outdated and 
inappropriate 2014 National Emission Inventory (NEI) for base year and 
future year emission assumptions,'' which the commenter claims is 
contrary to EPA guidance. The commenter states that ``EPA and others 
have concluded that 2014 is not useful for ozone sensitivity 
simulations,'' specifically asserting that 2014 was not conducive to 
ozone formation and did not contain high ozone periods adequate for an 
assessment of the impact of control technologies and air quality 
response. The commenter asserts that newer modeling platforms have been 
released with vastly improved estimates (specifically citing to a 2016 
NEI).\27\ The commenter specifically points to differences in 
NOX and VOC estimates in the later-released platforms, and 
provides a comparative analysis between the 2014 NEI and a 2016 NEI for 
Hamilton County and the Middle Tennessee Area. The commenter 
acknowledges that the 2014 NEI was the most current version at the time 
that Tennessee conducted its analysis. The commenter recommends the 
analysis be revised using the most current modeling platform and 
associated emission projections, and specifically references the 2016 
NEI. The commenter also recommends modeling be conducted using a 
meteorological and associated base year inventory that meets the 
requirements of EPA guidance for the determination of impact of control 
strategies and air quality response.
---------------------------------------------------------------------------

    \27\ The commenter's phrase ``2016 NEI'' appears to refer to the 
2016v1 emissions modeling platform produced by the National 
Emissions Inventory Collaborative.
---------------------------------------------------------------------------

    The commenter also claims that old and inappropriate assumptions 
were used, expressing concerns that the ozone sensitivity study was 
based on the 2007 SEMAP data projected to 2018. The commenter asserts 
that the non-interference analysis misuses the SEMAP study and points 
toward language in the report stating that ``these factors should not 
be used for anything other than identical conditions to those in the 
SEMAP analysis.'' The commenter asserts that the demonstration assumes 
a similar response in 2022, and that there is no basis for this 
assumption. The commenter characterizes the information from the SEMAP 
report as ``brute force factors'' that are not applicable because the 
factors are not tailored to the I/M removals in Hamilton County and the 
Middle Tennessee Area. The commenter points to differences between 
SEMAP projections and actual emissions as reported in the 2016 NEI, 
expressing concern about the ratios of NOX and VOC used in 
the non-interference demonstration. The commenter further asserts that 
the SEMAP data underestimates the ``contribution of vehicles to the 
inventory'' as compared to the 2016 NEI. The commenter also asserts 
that recent modeling indicates that on-road emission increases--and 
specifically Tennessee's motor vehicle source category--have a greater 
impact on regional air quality than what the demonstration calculates 
(in part, due to the assumption that each ton of a precursor has an 
equal impact on ozone formation). The commenter concludes that the 
sensitivity factors used in the demonstration are ``not directly 
applicable to today's ozone conditions and likely not representative of 
the air quality change due to the removal of the I/M programs.'' The 
commenter further states that Tennessee's ``recognition that its use of 
the scaling analysis would yield erroneous results should be adequate 
enough for the agency to reconsider using its analysis as a weight-of 
evidence approach to removal of the I/M program.'' If the analysis does 
not use air quality simulation, the commenter recommends an ```impact 
factor'-like application to determine the impact of the removal of the 
I/M program, [with] county and motor vehicle specific factors.''
    Response B4: As discussed above and in EPA's April 2021 SNPRM, EPA 
is not relying on Tennessee's sensitivity analysis in its determination 
that removal of the I/M program will not interfere with any applicable 
requirement under the CAA. To the extent the commenter is asserting 
that the emissions comparison analysis should be conducted with more 
recent data, such as later versions of the NEI, EPA disagrees with the 
commenter. The 2014 NEI was the latest available emissions data and 
served as the baseline data for both Middle Tennessee Area and the 
Chattanooga Area. In addition, the 2014 NEI matches the base year used, 
which was the 2014 attainment year. While subsequent emissions data are 
available since EPA received these SIP submissions, both areas continue 
to attain the NAAQS. The 2014 NEI was developed consistent with EPA 
guidance and sufficiently serves as the basis for this demonstration. 
EPA's conclusion that removal satisfies CAA section 110(l) is based on 
the technical analysis as described in detail in the April 2021 SNPRM 
and summarized above.
    Comment B5: A commenter discusses and compares a Georgia analysis 
to relax RVP requirements with the analysis to support removal of the 
Tennessee I/M program. The commenter points to two aspects of the 
Georgia analysis that differ from the Tennessee analysis: The 
substitution of quantifiable, permanent, surplus, enforceable, and 
contemporaneous measures to achieve equivalent emissions reductions to 
offset potential emissions increases; and a demonstration that 
emissions are well below (and will not exceed) motor vehicle emissions 
budgets (MVEBs). The commenter asserts that Tennessee's analysis to 
remove the I/M program does not include offsets nor does the analysis 
calculate and provide additional support of meeting current and future 
year MVEBs. The commenter further asserts that the MVEBs for Hamilton 
County were never calculated, and that concern was expressed about the 
Middle Tennessee Area meeting ``the old MVEBs'' at the Nashville Area 
Interagency Consultation Group meetings. The commenter concludes that 
the request to remove the I/M program does not have a supporting 
analysis comparable to Georgia's and may fall short for EPA approval.
    Response B5: EPA disagrees with these comments. With respect to the 
EPA-approved analysis to relax RVP requirements in Georgia, EPA notes 
that section 110(l) analyses are case-specific, and in the case of 
Georgia's request to relax RVP requirements for Atlanta, offsets were 
needed given the facts in that situation. See 84 FR 49470 (September 
20, 2019). Unlike Georgia, Tennessee has no areas designated as 
nonattainment or maintenance for the ozone NAAQS and does not currently 
have any violating ozone monitors. As discussed in the April 2021 
SNPRM, EPA is concluding that removal of the I/M program from the 
Tennessee SIP will not interfere with attainment or maintenance of the 
NAAQS or any other applicable requirement of the CAA.
    In addition, motor vehicle emission budgets (sometimes referred to 
in practice as ``MVEBs'') are a component of the regional emissions 
analysis for implementing transportation conformity requirements. See 
40 CFR 93.101 and 93.118. These comments are not relevant to this 
rulemaking because neither Hamilton County nor the Middle Tennessee 
Area are required to demonstrate transportation conformity for any 
pollutant, and therefore, no such

[[Page 45882]]

budgets are required to be developed for either area.
    Comment B6: With respect to Hamilton County,\28\ a commenter states 
``Tennessee appears to be taking credit for closures of three 
[Tennessee Valley Authority (TVA)] power plants in its non-interference 
demonstration.'' The commenter then goes on to assert that EPA cannot 
allow offsets for Hamilton County from outside of the nonattainment 
area because that would be a violation of the South Coast decision. The 
commenter concludes that EPA must only consider offsets to the I/M 
program that occur within the nonattainment area.
---------------------------------------------------------------------------

    \28\ This comment was received in docket EPA-R04-OAR-2019-0619 
only.
---------------------------------------------------------------------------

    Response B6: EPA disagrees with this comment. While the commenter 
does not provide a citation for the South Coast decision, EPA assumes 
the commenter is referring to the decision of the United States Court 
of Appeals for the District of Columbia Circuit (D.C. Circuit) in South 
Coast Air Quality Management District v. EPA, 882 F.3d 1138, 1146 (D.C. 
Cir. 2018), which addressed section 182 of the CAA and upheld EPA's 
interpretation that states may not take credit for reductions outside a 
nonattainment area for purposes of interim milestones towards 
attainment. This decision is not relevant to this action, as it 
addressed a different statutory provision not at issue here. Moreover, 
as discussed above, Tennessee is not providing offsets for the removal 
of the I/M program and, thus, no ``credits'' are being taken into 
account for facility closures or any other actions.
    Comment B7: A commenter asserts that the trends in air quality in 
the two areas are inconsistent with reductions in precursor emissions, 
claiming that although emissions estimates for motor vehicles are 
decreasing, air quality is stagnant in Hamilton County and 
deteriorating in the Middle Tennessee Area. The commenter also 
expresses concern about relying on the assumption that each ton of a 
pollutant precursor emission has an equal impact on air quality as 
compared to every other ton of the same pollutant precursor, regardless 
of emission source and where in the state the emissions occur, citing 
the uniqueness and nonlinearity of ozone precursors. The commenter 
states that on-road emission increases would have a greater impact on 
regional air quality than calculated and that an increase in emissions 
due to the removal of the I/M program may have an accelerated 
deterioration impact on the Areas' air quality.
    Response B7: The air quality data summarized in Response A3 
demonstrates that ozone air quality in Hamilton County and the Middle 
Tennessee Area is not worsening and is well below the 2015 8-hour ozone 
NAAQS. As discussed in the April 2021 SNPRM, removal of the I/M program 
from the Tennessee SIP will not interfere with attainment or 
maintenance of the NAAQS or any other applicable requirement of the 
CAA. In addition, as discussed in Response A4, I/M programs do not 
mandate emission controls systems on motor vehicles, unlike Federal 
motor vehicle emissions standards such as the Tier 3 rule. These 
Federal vehicle emission standards will remain with or without the I/M 
program in the Tennessee SIP for the Middle Tennessee Area and Hamilton 
County.
    Comment B8: A commenter asserts that EPA must take into account 
recent court decisions that will ``have a devastating impact on the 
state's ability to ensure non-interference.'' The commenter 
specifically points to the ``Wisconsin and New York decisions,'' which 
``vacated and remanded these programs back to EPA, essentially wiping 
them out entirely.'' The commenter claims that Tennessee cannot claim 
credit for any reductions attributable to the programs. Further, the 
commenter states EPA must check to make sure the state does not 
interfere with any downwind states' ability to meet the NAAQS.
    Response B8: EPA has confirmed that the changes being approved by 
EPA in this action do not interfere with other states' ability to meet 
the 2008 ozone NAAQS. Although it is unclear from the comment, in 
describing programs promulgated under the good neighbor provision, CAA 
section 110(a)(2)(D)(i)(I), EPA assumes the commenter is referring to 
the Cross-State Air Pollution Rule (CSAPR) Update. The CSAPR Update 
addresses NOX pollution transported to other states that 
significantly contributes to nonattainment or interferes with 
maintenance of the 2008 ozone NAAQS.\29\ Among other things, the CSAPR 
Update requires reductions of NOX from power plants during 
the annual ozone season from May 1 to September 30 in 22 states, 
including Tennessee. Although EPA found the CSAPR Update may only 
partially address the good neighbor obligations for most covered 
states, EPA found the rule fully addresses Tennessee's good neighbor 
obligation for this NAAQS. See 81 FR 74504, 74540 (October 26, 2016). 
That conclusion was based on an assessment of air quality in the 
eastern U.S. with implementation of the CSAPR Update, and it accounted 
for emissions from all source sectors, including mobile sources.
---------------------------------------------------------------------------

    \29\ The CSAPR Update is a rule that followed the original CSAPR 
rulemaking in 2011. CSAPR requires certain states in the eastern 
half of the U.S. to improve air quality by reducing power plant 
emissions of NOX and SO2 that cross state 
lines and contribute to smog and soot pollution in downwind states. 
On September 7, 2016, EPA revised the CSAPR ozone season 
NOX program by finalizing an update to CSAPR for the 2008 
ozone National Ambient Air Quality Standards, known as the CSAPR 
Update. The CSAPR Update ozone season NOX program was 
designed to largely replace the original CSAPR ozone season 
NOX program starting on May 1, 2017, and further reduce 
summertime NOX emissions from power plants in the eastern 
U.S.
---------------------------------------------------------------------------

    The CSAPR Update was reviewed and generally upheld in Wisconsin v. 
EPA, 983 F.3d 303 (D.C. Cir. 2019). Contrary to the commenter's 
assertion that the rule was vacated, the D.C. Circuit merely remanded 
the rule without vacatur because, for states other than Tennessee, the 
rule did not provide a full remedy by the next relevant attainment date 
under CAA section 181. Thus, the CSAPR Update remains in effect. The 
decision in New York v. EPA, 781 F. App'x 4 (D.C. Cir. 2019) vacated a 
separate rule, the CSAPR Close-Out, but this rule did not impose 
additional reductions and only purported to demonstrate, based on new 
modeling analysis of the year 2023, that the CSAPR Update was a full 
remedy for 20 states. In the New York case cited by commenter, the D.C. 
Circuit found this conclusion incorrect as a matter of law in light of 
its holding in Wisconsin because EPA analyzed a year beyond the next 
attainment date without sufficient justification. Tennessee's 
obligations were not at issue in the Close-Out rule. EPA notes that the 
aspects of the CSAPR Update affecting Tennessee were not challenged in 
the litigation over the rule and are not affected by the remand of the 
rule in Wisconsin.
    EPA believes the projected increase in mobile source emissions from 
the removal of Tennessee's I/M program does not affect EPA's prior 
finding in the CSAPR Update that the State of Tennessee has no further 
interstate transport obligations for the 2008 8-hour ozone NAAQS. In 
the section 110(l) analysis for this action, EPA analyzed the impacts 
of removing the I/M program in Hamilton County and the Middle Tennessee 
Area from the subject final rule and found that the largest projected 
increase in mobile source emissions in these areas would result in a 
combined projected increase of 579 tons in 2022, or a 2 percent 
increase in total anthropogenic NOX emissions in

[[Page 45883]]

these areas.\30\ Therefore, the net change in total anthropogenic 
emissions across the entire State of Tennessee would be much less than 
the projected 2 percent increase in NOX emissions.
---------------------------------------------------------------------------

    \30\ In 2022, emissions of VOC are projected to increase by 740 
tons, or a 1.7 percent increase in total anthropogenic VOC 
emissions. In the context of interstate ozone transport, EPA focuses 
on NOX as the key ozone precursor pollutant.
---------------------------------------------------------------------------

    On October 30, 2020, in the NPRM for the Revised CSAPR Update, EPA 
released and accepted public comment on updated 2023 modeling that used 
a 2016 emissions platform developed under the EPA/Multi-Jurisdictional 
Organization (MJO)/state collaborative project.\31\ On March 15, 2021, 
EPA signed the final Revised CSAPR Update using the same modeling 
released at proposal.\32\ In this modeling, EPA found that the highest 
contribution in 2023 from the entire State of Tennessee to any downwind 
receptor identified as having a nonattainment or maintenance problem 
for the 2008 ozone standard is projected to be 0.32 ppb. This amount of 
contribution is well below the 1 percent of the NAAQS threshold used in 
EPA's good neighbor framework for determining whether an upwind state 
contributes to a nonattainment or maintenance receptor under the 2008 
ozone NAAQS (i.e., 0.75 ppb). The small amount of projected increase in 
NOX emissions in Tennessee as a result of this action, 
combined with the fact that the highest modeled contributions from this 
state are well below the 1 percent threshold, support the conclusion 
that the projected increase in mobile source emissions does not affect 
EPA's prior decision that Tennessee has no remaining interstate 
transport obligations under the 2008 ozone NAAQS.
---------------------------------------------------------------------------

    \31\ See 85 FR 68964, 68981 (October 30, 2020). The results of 
this modeling are included in a spreadsheet in the dockets for this 
action. The underlying modeling files are available for public 
review in the docket for the Revised CSAPR Update (EPA-HQ-OAR-2020-
0272).
    \32\ See 86 FR 23054 at 23075, 23164 (April 30, 2021).
---------------------------------------------------------------------------

    This final action does not make any finding regarding Tennessee's 
interstate transport obligations for the 2015 8-hour ozone NAAQS. EPA 
has not yet taken final action on Tennessee's good neighbor SIP 
submission for the 2015 8-hour ozone NAAQS.
    Comment B9: In response to EPA's April 2021 SNPRM, a commenter 
asserts that EPA's proposed conclusion that ``removal of the I/M 
program will not interfere with other states' ability to attain and 
maintain the 2008 ozone NAAQS'' is based on ``an air quality modeling-
based technique'' performed for the Revised CSAPR Update that contains 
``an error in the source apportionment model'' that was ``discovered in 
December 2020.'' Specifically, the commenter asserts that EPA ``does 
not know whether the specific beta version of the model used in their 
analysis contained the bug and associated source apportionment error.'' 
The commenter further states that ``[n]o known quantification of the 
error has been calculated and therefore it is unknown just how 
significant a change might be seen in the upwind state contribution to 
downwind receptors under the 2008 Ozone NAAQS or in potential 
application for future consideration of significant contribution under 
the 2015 Ozone NAAQS,'' and requests that EPA ``correct[] the source 
apportionment results and significant contribution calculations with 
the corrected version of the air quality model'' before making a final 
decision on removal of the I/M program from the Tennessee SIP.
    Response B9: The commenter is correct that EPA relies on modeling 
developed for the Revised CSAPR Update (RCU) to determine that removal 
of the I/M program will not interfere with other states' ability to 
attain and maintain the 2008 ozone NAAQS under the good neighbor 
provision of the CAA. The modeling was made available to the public in 
the proposed RCU on October 30, 2020. See 85 FR 68964. The comment 
period for that rulemaking was open from October 30, 2020, through 
December 14, 2020. Id. Petitions for review of the RCU were due by June 
29, 2021 in the D.C. Circuit. See 86 FR 23054, 23164 (April 30, 2021); 
see also CAA section 307(b). Additionally, EPA had previously 
determined that the CSAPR Update Federal implementation plan for 
Tennessee eliminated the State's significant contribution to downwind 
ozone nonattainment or maintenance for the 2008 8-hour ozone NAAQS. See 
81 FR 74504, 74508 (October 26, 2016).
    EPA disagrees that there was an error in the modeling that is 
material to this action. EPA used CAMX version 7, beta6 for 
the air quality modeling to support the RCU. This version of 
CAMX was the most up-to-date version of the model available 
at the time EPA performed air quality modeling for the RCU. The final 
CAMX version 7.0 was released by the model developer, 
Ramboll, in May of 2020. This version was a different version than the 
beta6 version EPA used in its modeling.
    Following release of version 7.0, the commenter is correct that an 
error was identified in the model code that affected model predicted 
concentrations and, therefore, contributions when the model was run 
using ozone or PM2.5 source apportionment tools (SAT) for 
calculating source contributions to pollutant concentrations. 
Specifically, when CAMX version 7.0 was run with SAT, the 
pollutant species emissions in the input point source emissions file 
did not match the species in the core model. For example, it is 
possible that the model might have assigned point source emissions of 
nitric oxide (NO) in the input emissions file to SO2 in the 
model run. Thus, the effects on model predictions due to this type of 
mismatch of pollutant emissions and concentrations would likely be 
significant. Once this error was identified, it was quickly 
corrected.\33\ Further, the code error in version 7.0 did not occur in 
CAMX model runs when SAT were not invoked (i.e., model runs 
without SA).
---------------------------------------------------------------------------

    \33\ From CAMXversion 7.10 release notes, January 5, 
2021: ``Fixed bug that improperly mapped point source species to 
model species when running SAT. Implications: Core model point 
source species were improperly injected affecting core model 
concentrations and by extension SAT concentrations.'' See https://camx-wp.azurewebsites.net/Files/Release_notes.v7.10.txt
---------------------------------------------------------------------------

    EPA contacted Ramboll to determine whether this coding error in the 
final release of version 7.0 was also present in any of the pre-release 
beta versions, particularly beta6, which EPA had used for the RCU. 
Ramboll initially stated that they had no information to determine 
whether or not the code error was in beta6 or any of the other version 
7.0 beta codes. However, in consultation with Ramboll, EPA found that 
this could be determined by comparing the model predictions from a run 
without SAT to a companion model run with SAT invoked. If the 
predictions are the same, then the code EPA used for the RCU did not 
contain this coding error.
    For the RCU, EPA had performed two CAMX model runs for 
2023, one without SAT and one with SAT. Thus, to respond to this 
comment, EPA compared the ozone predictions from these two runs to 
identify whether or not there are any notable differences between the 
two. As an example, Table 5 provides the maximum daily 8-hour ozone 
predictions for the 2023 emissions case for the month of July at the 
RCU nonattainment receptor site in Stratford, Connecticut. In addition, 
Figure 1, provided in the dockets for this final rulemaking, shows the 
maximum daily 8-hour ozone concentrations in each model grid cell on 
one of the days in June based on 2023 modeling without and with 
SAT.\34\

[[Page 45884]]

In both the table and the figure, model predictions without and with SA 
are essentially identical. Thus, based on EPA's analysis, the Agency 
concludes that the error referenced by the commenter was not in the 
CAMX model code that EPA used for the RCU modeling.
---------------------------------------------------------------------------

    \34\ Figure 1: Model-predicted 2023 maximum daily 8-hour ozone 
concentrations (ppb) for June 20 from CAMX v7beta6 model 
runs without SAT (top) and with STA (bottom); both maps use the same 
0 to 80 ppb scale for depicting concentrations.
---------------------------------------------------------------------------

    For the reasons above, EPA disagrees with the commenter's 
assertions regarding EPA's section 110(l) analysis for Tennessee's good 
neighbor obligations for the 2008 ozone NAAQS, and EPA is confident 
that the CAMX modeling used in the RCU and to support this 
action is reliable.

  Table 5--Model-Predicted Maximum Daily 8-Hour Ozone Concentrations (ppb) Without and With SA for the Month of
                                July at the Stratford, Connecticut Receptor Site
----------------------------------------------------------------------------------------------------------------
                         Month                                  Day          2023 without SA      2023 with SA
----------------------------------------------------------------------------------------------------------------
7......................................................                  1             38.945             38.945
7......................................................                  2             33.380             33.380
7......................................................                  3             42.748             42.748
7......................................................                  4             58.685             58.685
7......................................................                  5             45.056             45.056
7......................................................                  6             75.488             75.488
7......................................................                  7             61.284             61.283
7......................................................                  8             50.325             50.325
7......................................................                  9             28.097             28.097
7......................................................                 10             34.460             34.460
7......................................................                 11             30.646             30.646
7......................................................                 12             64.362             64.362
7......................................................                 13             43.699             43.699
7......................................................                 14             49.537             49.537
7......................................................                 15             59.426             59.426
7......................................................                 16             58.222             58.222
7......................................................                 17             68.067             68.067
7......................................................                 18             77.420             77.421
7......................................................                 19             32.556             32.556
7......................................................                 20             36.040             36.040
7......................................................                 21             64.457             64.457
7......................................................                 22             72.682             72.682
7......................................................                 23             37.790             37.790
7......................................................                 24             47.433             47.433
7......................................................                 25             82.696             82.696
7......................................................                 26             40.812             40.812
7......................................................                 27             48.118             48.118
7......................................................                 28             62.982             62.982
7......................................................                 29             52.004             52.004
7......................................................                 30             60.485             60.485
7......................................................                 31             42.559             42.559
----------------------------------------------------------------------------------------------------------------

    Comment B10: A commenter identifies a number of regulations and 
policies that have either been rolled back or are proposed to be rolled 
back and expresses concern that the non-interference analysis did not 
account for the status of these rollbacks. The commenter states that 
air quality in the region has ``shown deterioration and movement 
towards nonattainment of the various NAAQS'' due to the rollbacks. 
Also, the commenter asserts that impacts from as far away as California 
or New York could impact air in Tennessee. The commenter also concludes 
that there are emissions increases attributable to the rollbacks and 
that they should be taken into account to accurately assess air quality 
prior to removal of the I/M programs from the SIP.
    Response B10: EPA does not agree with the commenter's assertion 
that Tennessee should have or could have accounted for the final or 
proposed rollbacks identified by the commenter. As described above, 
Tennessee used the latest available information when the SIP revision 
was developed with EPA's MOVES2014b model and associated technical and 
policy guidance,\35\ and the SIP revision's new on-road mobile source 
inventory was based on the EPA's vehicle and fuel standard rulemakings 
that are relevant for criteria pollutants.
---------------------------------------------------------------------------

    \35\ See EPA's July 2014 ``Policy Guidance on the Use of 
MOVES2014 for State Implementation Plan Development, Transportation 
Conformity, and Other Purposes'' (hereinafter MOVES 2014 Guidance). 
This document is available at https://nepis.epa.gov/Exe/ZyPDF.cgi?Dockey=P100K4EB.pdf.
---------------------------------------------------------------------------

    With respect to a number of the rollbacks that the commenter 
directly asserts ``could be considered to have an impact on the 
Tennessee airshed,'' the commenter did not provide any documents or 
citations, therefore, in some cases, it is not entirely clear what 
changes the commenter is referring to. However, based on the changes 
that EPA believes the commenter to be concerned with, EPA disagrees 
that the changes will impact Tennessee air quality. For example, the 
rule titled ``Oil and Natural Gas Sector: Emission Standards for New, 
Reconstructed, and Modified Sources Review,'' 85 FR 57018 (September 
14, 2020), was disapproved under the Congressional Review Act,\36\ and 
the fuel volatility waivers under the rule titled ``Modifications to 
Fuel Regulations To Provide Flexibility for E15; Modifications to RFS 
RIN Market Regulations,'' 84 FR 26980 (June 10, 2019), were vacated by 
the D.C. Circuit. See Am. Fuel & Petrochemical Manufacturers v. EPA, 
No. 19-1124, 2021 WL 2755032, at *7 (D.C. Cir. July

[[Page 45885]]

2, 2021). The commenter also cites to a regulation that tracks--rather 
than controls--emissions; \37\ denials of petitions that were before 
the agency that did not alter any emissions controls in place, some of 
which have been sent back to EPA; \38\ and guidance that, by its very 
nature, does not impose binding requirements.\39\
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    \36\ See, e.g., White House signing statement at https://www.whitehouse.gov/briefing-room/statements-releases/2021/06/30/bills-signed-s-j-res-13-s-j-res-14-s-j-res-15/.
    \37\ National Performance Management Measures; Assessing 
Performance of the National Highway System, Freight Movement on the 
Interstate System, and Congestion Mitigation and Air Quality 
Improvement Program, 83 FR 24920 (May 31, 2018).
    \38\ See, e.g., New York v. EPA, 964 F.3d 1214 (D.C. Cir. 2020); 
Maryland v. EPA, 958 F.3d 1185 (D.C. Cir. 2020).
    \39\ See, e.g., August 31, 2018 Memo from Peter Tsirigotis 
(OAQPS) re Analysis of Contribution Thresholds for Use in Clean Air 
Act Section 110(a)(2)(D)(i)(I) Interstate transport State 
Implementation Plan submissions for the 2015 Ozone National Ambient 
Air Quality Standards, available at https://www.epa.gov/sites/default/files/2018-09/documents/contrib_thresholds_transport_sip_subm_2015_ozone_memo_08_31_18.pdf 
(Memo ``does not impose binding, enforceable requirements on any 
party''); October 9, 2020 Memo from Andrew Wheeler re Inclusion of 
Provisions Governing Periods of Startup, Shutdown, and Malfunctions 
in State Implementation Plans (``This memorandum does not alter in 
any way the determinations made in the 2015 SSM SIP Action that 
identified specific state SIP provisions that were substantially 
inadequate to meet the requirements of the Act. In order to change 
those determinations and alter or withdraw the 2015 SIP call, 
subsequent actions will need to be taken.'').
---------------------------------------------------------------------------

    With respect to any pending or proposed changes, per EPA's 
Emissions Inventory Guidance, ``[i]mpacts of proposed [Federal] rules 
are rarely included'' in EPA emissions projections ``as the changes in 
emissions impacts can be very large between proposed and final rules.'' 
\40\ See ``Emissions Inventory Guidance for Implementation of Ozone and 
Particulate Matter National Ambient Air Quality Standards (NAAQS) and 
Regional Haze Regulations,'' May 2017, at 122.\41\
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    \40\ EPA notes that the commenter references ``withdrawal of a 
proposed rule aimed at reducing pollutants, including air pollution, 
at sewage treatment plants.'' However, the commenter cites to a 
final rule ``National Emission Standards for Hazardous Air 
Pollutants: Publicly Owned Treatment Works Residual Risk and 
Technology Review,'' 82 FR 49513 (Oct. 26, 2017), within which EPA 
did not take final action on several provisions that were proposed, 
but did not withdraw proposal as to those provisions. To the extent 
that the commenter refers to the provisions that were not acted 
upon, those changes remain pending, and thus, EPA's emissions 
projections will not take those into account.
    \41\ Available at https://www.epa.gov/sites/production/files/2017-07/documents/ei_guidance_may_2017_final_rev.pdf.
---------------------------------------------------------------------------

    Furthermore, the commenter did not provide any technical 
information or analysis to substantiate their claims that the final or 
proposed rollbacks in combination with the removal of the I/M program 
from the Tennessee SIP would cause either Hamilton County or the Middle 
Tennessee Area to interfere with attainment or maintenance of the 
NAAQS. In addition, any possible air quality impacts from many of the 
rollbacks are speculative and hypothetical in nature. In contrast, 
EPA's analysis projects that 2022 total emissions without the I/M 
program are significantly less than 2014 total emissions for both the 
Middle Tennessee and Hamilton County areas. See Section III, above, and 
EPA's April 2021 SNPRM.\42\
---------------------------------------------------------------------------

    \42\ See 86 FR 21248. With respect to the Middle Tennessee Area: 
``Even without the I/M program in 2022, emissions of NOX, 
VOC, and CO are projected to decrease by 47.1 percent, 15.1 percent, 
and 23.9 percent, respectively, from 2014 levels.'' With respect to 
Hamilton County: ``Even without the I/M program in 2022, emissions 
of NOX, VOC, and CO are expected to decrease by 27.0 
percent, 8.1 percent and 18.7 percent, respectively from 2014 
levels.''
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C. Responses to Comments Outside the Scope of This Rulemaking

    EPA received numerous comments that are outside the scope of this 
rulemaking. Even though EPA is not obligated to respond to these 
comments, EPA nonetheless has provided responses below in order to 
assist the public's understanding of EPA's final action.
    Comment C1: Many commenters opposed to the removal of the I/M 
program acknowledge improved vehicle standards, but believe that the I/
M program is still needed as a check to ensure that citizens are 
maintaining their vehicles (including for safety inspections).
    Response C1: To the extent commenters are concerned that removal of 
the I/M program will result in citizens neglecting to maintain their 
vehicles or affecting vehicle safety, those concerns are outside the 
scope of this rulemaking. States have primary responsibility for 
deciding how to attain and maintain the NAAQS. Tennessee has opted to 
remove the I/M program from its SIP. Under the CAA, the sole issue for 
EPA's consideration in this rulemaking is whether removing the I/M 
program from the SIP would be consistent with CAA provisions, including 
whether discontinuation is expected to interfere with attainment and 
maintenance of air quality standards or any applicable requirement of 
the CAA. EPA is approving removal of the I/M program from the SIP 
because removal is consistent with the requirements of the CAA. The 
option the commenter suggests to continue an I/M program to ensure 
vehicles are maintained may be considered and implemented at the local 
level without EPA's review or approval.
    EPA agrees that vehicles are cleaner now as a result of EPA rules 
since the early 2000s that control emissions from on-road vehicles. EPA 
refers commenters to Response A4 for more information concerning EPA 
standards.
    Comment C2: A commenter opines that the I/M program is needed and 
notes ``the testing procedures and equipment need updated badly.'' The 
commenter goes on to state that ``A vehicle should not fail emissions 
for a certain code that has nothing to do with emissions output. All 
vehicles should be tested by their exhaust to see exactly what the air 
to fuel ratio is. The software needs updates as well. Very old 
equipment.'' Other commenters expressed concerns about whether the 
testing procedures themselves met the intended purpose of the I/M 
program. Some commenters questioned why the I/M program was only 
required in six counties in Tennessee and wanted the program removed 
for those counties, while others wanted the program expanded statewide 
and even nationwide. Other commenters expressed concerns about I/M 
program avoidance. They noted that citizens register their vehicles in 
surrounding counties that do not have I/M requirements, yet commute 
back and forth or even live in areas where I/M is required. Some of the 
commenters expressed concern about program avoidance as support for the 
removal of the I/M program. Commenters opined on whether or not the 
cost of the program and related expenses were worth keeping the 
program. Some commenters expressed concern related to the impact of the 
test and repair costs on the elderly and low-income citizens. Others 
asserted that this was a way to generate revenue and an unfair tax. 
Those who did not support removal of the I/M program opined that the I/
M program was worth the benefit for air quality. Another commenter 
expressed concerns with regard to ``replacements'' to the I/M program. 
The commenter also stated that ``we . . . must be able to maintain the 
progress that has been made.'' One commenter opined that there is a 
``likelihood that current income limitations will impact future 
replacement of aging vehicles.'' Another commenter said that ``[t]he 
emissions program is doing more good than harm for the community.'' 
Some adverse comments indicated that removal of I/M could lead to 
people not feeling the need to maintain their cars, which will lead to 
even bigger problems.
    Response C2: These comments are all outside the scope of this 
rulemaking. The design, technology, and implementation issues 
associated with

[[Page 45886]]

an I/M program are outside this scope of this rulemaking. With regard 
to the geographical coverage area of Tennessee's I/M program, EPA notes 
that the I/M program is not currently mandated by the CAA or EPA 
regulations in any part of Tennessee or throughout the entirety of the 
United States.\43\ Additionally, the cost structure of individual I/M 
programs is not a factor EPA evaluates when determining approvability 
of a SIP revision to remove I/M requirements. A commenter's assertion 
that the SIP revision is a ``repeal and replace'' is not clear. 
Tennessee's February 2020 SIP revisions only addressed removal of the 
I/M program, without a replacement program or offsets.
---------------------------------------------------------------------------

    \43\ Except as required by CAA sections 182(a)(2)(B), 182(b)(4), 
and 182(c)(3) for certain ozone nonattainment areas and sections 
187(a)(4) and 187(a)(6) for certain CO nonattainment areas.
---------------------------------------------------------------------------

    See Responses A5 and A10 regarding the scope of EPA's review and 
the discretionary nature of Tennessee's program, and the April 2021 
SNPRM regarding EPA's determination that section 110(l) requirements 
have been met.
    Comment C3: Commenters suggest that EPA needs to monitor emissions 
released from mobile sources outside of I/M programs, such as planes, 
trains, trucks, and buses in order to either improve air quality or 
prevent it from deteriorating.
    Response C3: These comments are outside the scope of this 
rulemaking. As discussed in Response A5, CAA section 110(k) requires 
EPA to approve SIP revisions that meet all applicable CAA requirements. 
While monitoring and regulating emissions from planes, trains, trucks, 
buses and any other ``mobile source'' that are not passenger vehicles 
is out of scope of this action, EPA notes that the Agency's Office of 
Transportation and Air Quality (OTAQ) addresses emissions from the 
range of mobile sources. The commenters are encouraged to visit OTAQ's 
website for more information at https://www.epa.gov/aboutepa/about-office-air-and-radiation-oar#otaq to learn more about these programs.
    Comment C4: A commenter opines that removing the I/M program is a 
bad idea and recalls polluting cars and trucks before the I/M program 
was enacted. The commenter goes on to say ``My only issue in 
Chattanooga is the mayor has put in bike lanes everywhere that are used 
very seldomly and reducing the auto lanes creates huge traffic 
backups.'' The commenter goes on to say that bike lanes cause more 
pollution and offsets what emissions benefits are achieved.
    Response C4: For reasons explained in the April 2021 SNPRM, EPA has 
determined that section 110(l) requirements have been met. EPA also 
notes that cars and trucks are cleaner, absent the I/M program, because 
of Federal engine and fuel standards that all vehicles must comply 
with. Thus, vehicles today are much cleaner than they were when the I/M 
program was enacted in Hamilton County in the early 2000s, as vehicle 
and fuel standards have become more stringent since then. To the extent 
that the commenter expresses concerns about bike lanes and their impact 
on traffic and emissions, these comments are outside the scope of this 
rulemaking as I/M programs do not regulate bike lanes.
    Comment C5: A commenter in support of the emissions testing in 
Hamilton County states that ``[i]t not only has helped clean up the air 
in the county, it has also drawn other large businesses to our Area. 
Volkswagen and Amazon both came here due in part to Hamilton County's 
emission testing.'' Another commenter expresses concern for their 
industry and stated: ``If Chattanooga and Nashville Ozone Standards are 
changed in the future and the EPA is no longer able to effectively 
regulate `on road' mobile source emissions, stationary sources and our 
member's off-road fleets could, and likely would, be over regulated due 
the inability to regulate the much more impactful on-road mobile 
sources. This could create a severe adverse impact to our industry.''
    Response C5: These comments are outside the scope of this 
rulemaking. In evaluating whether a SIP revision is approvable, EPA 
must consider the relevant CAA provisions and does not consider what 
impacts, if any, the SIP revision would have for attracting businesses 
to an area. Nor does EPA try to anticipate what the State may do for 
future air quality planning. As detailed in the April 2021 SNPRM, EPA 
has determined that approval of these SIP revisions will not interfere 
with attainment or maintenance of the NAAQS or any other requirement of 
the CAA. EPA's action to remove the I/M program does not preclude the 
state or local government from maintaining an I/M program at the state 
or local level.
    Comment C6: One commenter asserted that during Tennessee's state 
comment period it did not have access to inventory materials in 
timeframes necessary to conduct an independent review and modeling of 
the I/M program removal.
    Response C6: This comment is outside the scope of this rulemaking 
because it relates to Tennessee's State comment period. In addition, 
EPA notes that the inventories were available to the public during 
EPA's public comment period on the June 2020 NPRMs and the April 2021 
SNPRM. See regulations.gov document numbers EPA-R04-OAR-2019-0618-0002 
(pdf pages 16 and 21) and EPA-R04-OAR-2019-0619-0002 (pdf pages 16, 17 
and 22).

V. Incorporation by Reference

    In this document, EPA is finalizing regulatory text that includes 
incorporation by reference. As described in the amendments to 40 CFR 
part 52 set forth below, EPA is finalizing the removal of Tennessee 
Regulation Chapter 1200-3-29--``Light Duty Vehicle Inspection and 
Maintenance;'' and Nashville-Davidson County Regulation No. 8--
``Regulation of Emissions from Light-Duty Motor Vehicles through 
Mandatory Vehicle Inspection and Maintenance Program,'' from the 
Tennessee SIP, which is incorporated by reference in accordance with 
the requirements of 1 CFR part 51.

VI. Final Action

    EPA is approving the SIP revisions and removing the I/M 
requirements for the Middle Tennessee Area (i.e., Davidson, Sumner, 
Rutherford, Williamson and Wilson Counties) and Hamilton County from 
the Tennessee SIP. EPA is taking these actions because removing the 
requirements is consistent with the CAA and applicable regulations.

VII. Statutory and Executive Order Reviews

    Under the CAA, the Administrator is required to approve SIP 
submissions that comply with the provisions of the Act and applicable 
Federal regulations. See 42 U.S.C. 7410(k); 40 CFR 52.02(a). Thus, in 
reviewing SIP submissions, EPA's role is to approve state choices, 
provided that they meet the criteria of the CAA. These actions merely 
approve state law as meeting Federal requirements and does not impose 
additional requirements beyond those imposed by state law. For that 
reason, these actions:
     Are not significant regulatory actions subject to review 
by the Office of Management and Budget under Executive Orders 12866 (58 
FR 51735, October 4, 1993) and 13563 (76 FR 3821, January 21, 2011);
     Do not impose an information collection burden under the 
provisions

[[Page 45887]]

of the Paperwork Reduction Act (44 U.S.C. 3501 et seq.);
     Are certified as not having a significant economic impact 
on a substantial number of small entities under the Regulatory 
Flexibility Act (5 U.S.C. 601 et seq.);
     Do not contain any unfunded mandate or significantly or 
uniquely affect small governments, as described in the Unfunded 
Mandates Reform Act of 1995 (Pub. L. 104-4);
     Do not have federalism implications as specified in 
Executive Order 13132 (64 FR 43255, August 10, 1999);
     Are not an economically significant regulatory action 
based on health or safety risks subject to Executive Order 13045 (62 FR 
19885, April 23, 1997);
     Are not a significant regulatory action subject to 
Executive Order 13211 (66 FR 28355, May 22, 2001);
     Are not subject to requirements of Section 12(d) of the 
National Technology Transfer and Advancement Act of 1995 (15 U.S.C. 272 
note) because application of those requirements would be inconsistent 
with the CAA; and
     Do not provide the EPA with the discretionary authority to 
address, as appropriate, disproportionate human health or environmental 
effects, using practicable and legally permissible methods, under 
Executive Order 12898 (59 FR 7629, February 16, 1994).
    The SIP is not approved to apply on any Indian reservation land or 
in any other area where EPA or an Indian tribe has demonstrated that a 
tribe has jurisdiction. In those areas of Indian country, the rule does 
not have tribal implications as specified by Executive Order 13175 (65 
FR 67249, November 9, 2000), nor will it impose substantial direct 
costs on tribal governments or preempt tribal law.
    The Congressional Review Act, 5 U.S.C. 801 et seq., as added by the 
Small Business Regulatory Enforcement Fairness Act of 1996, generally 
provides that before a rule may take effect, the agency promulgating 
the rule must submit a rule report, which includes a copy of the rule, 
to each House of the Congress and to the Comptroller General of the 
United States. The EPA will submit a report containing this action and 
other required information to the U.S. Senate, the U.S. House of 
Representatives, and the Comptroller General of the United States prior 
to publication of the rule in the Federal Register. A major rule cannot 
take effect until 60 days after it is published in the Federal 
Register. This action is not a ``major rule'' as defined by 5 U.S.C. 
804(2).
    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 October 18, 2021. Filing a petition for 
reconsideration by the Administrator of this final rule does not affect 
the finality of this action 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 in 40 CFR Part 52

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

    Dated: August 5, 2021.
John Blevins,
Acting Regional Administrator, Region 4.

    For the reasons stated in the preamble, EPA amends 40 CFR part 52 
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.

Subpart RR--Tennessee

0
2. Section 52.2220 is amended by:
0
a. In paragraph (c):
0
i. In Table 1, removing the heading and all entries for ``Chapter 1200-
3-29--Light Duty Vehicle Inspection and Maintenance'' in their 
entirety; and
0
ii. In Table 5, under the heading ``Article II. Standards for 
Operation,'' removing the entry for ``Regulation No. 8--Regulation of 
Emissions from Light-Duty Motor Vehicles through Mandatory Vehicle 
Inspection and Maintenance Program'' in its entirety.
0
b. In paragraph (e), in the table, revising the entry for ``Attainment 
Demonstrations for Early Action Compact Areas''.
    The revision reads as follows:


Sec.  52.222052  Identification of plan.

* * * * *
    (e) * * *

                                EPA-Approved Tennessee Non-Regulatory Provisions
----------------------------------------------------------------------------------------------------------------
                                        Applicable
    Name of nonregulatory SIP         geographic or          State       EPA approval          Explanation
            provision               nonattainment area  effective date       date
----------------------------------------------------------------------------------------------------------------
 
                                                  * * * * * * *
Attainment Demonstrations for      Chattanooga,               12/31/04       8/17/2021  With the exception of
 Early Action Compact Areas.        Nashville, and Tri-                                  Tennessee Regulation
                                    Cities Early                                         Chapter 1200-3-29 and
                                    Action Compact                                       Nashville-Davidson
                                    Areas.                                               County Regulation No.
                                                                                         8, with a State
                                                                                         effective date of 2/26/
                                                                                         2020.
 
                                                  * * * * * * *
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[FR Doc. 2021-17214 Filed 8-16-21; 8:45 am]
BILLING CODE 6560-50-P