Federal Register / Vol. 86, No. 156 / Tuesday, August 17, 2021 / Rules and Regulations 45871 

1EPA officially received Tennessee’s I/M SIP 

revisions on February 27, 2020. 

2The 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. 

4Throughout 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. 

• Is not subject to requirements of 

Section 12(d) of the National 

Technology Transfer and Advancement 

Act of 1995 (15 U.S.C. 272 note) because 

application of those requirements would 

be inconsistent with the Clean Air Act; 

and 

• Does not provide 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). 

In addition, the SIP is not approved 

to apply on any Indian reservation land 

or in any other area where EPA or an 

Indian tribe has demonstrated that a 

tribe has jurisdiction. In those areas of 

Indian country, the rule does not have 

tribal implications and will not impose 

substantial direct costs on tribal 

governments or preempt tribal law as 

specified by Executive Order 13175 (65 

FR 67249, November 9, 2000). 

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. 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 Clean 

Air Act, 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 11, 2021. 

Deborah Szaro, 

Acting Regional Administrator, EPA Region 

1. 

[FR Doc. 2021–17543 Filed 8–16–21; 8:45 am] 

BILLING CODE 6560–50–P 

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. 

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 

benjamin.lynorae@epa.gov. 

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 nonregulatory 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). 

II. Background 

On May 15, 2018, a Tennessee law 

was signed that states that ‘‘no 


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5Tenn. 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. 

6The 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. 

7The 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. 

8EPA 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. 

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

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) noninterference 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. 

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 noninterference 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 


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10Comments 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. 

11For 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). 

12See https://www.epa.gov/criteria-airpollutants/naaqs-table. 

demonstrate non-interference under 

these circumstances. 

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) noninterference demonstration; and (3) 

comments outside the scope of this 

rulemaking. EPA’s responses to 

comments are provided below. 

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). 

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. 

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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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. 

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. 

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. 

16As 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. 

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. 

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.’’ 

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

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. 

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 

Monitor name County Design value 

2012–2014 

Design value 

2013–2015 

Design value 

2014–2016 

Design value 

2015–2017 

Design value 

2016–2018 

Design value 

2017–2019 

Design value 

2018–2020 

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 

* 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. 


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*** 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 

Monitor Site Name Design value 

2012–2014 

Design value 

2013–2015 

Design value 

2014–2016 

Design value 

2015–2017 

Design value 

2016–2018 

Design value 

2017–2019 

Design value 

2018–2020 

Eastside Utility ............. 69 66 68 67 66 64 62 

Soddy Daisy High 

School ....................... 67 64 65 65 64 64 61 

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 

Monitor Site name County AQS ID 2012 2013 2014 2015 2016 2017 2018 2019 2020 

East Health ........................... Davidson (Middle Tennessee 

Area).

47–037–0011 76 (*) 65 67 66 64 68 65 60 

Percy Priest Dam ................. Davidson (Middle Tennessee 

Area).

47–037–0026 (*) 60 71 64 68 62 71 63 61 

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 Tennessee 

Area).

47–165–0007 83 68 66 67 68 64 68 66 63 

Fairview Middle School ........ Williamson (Middle Tennessee Area).47–187–0106 74 62 63 61 61 58 63 60 57 

Cedars of Lebanon ............... Wilson (Middle Tennessee 

Area).

47–189–0103 77 62 64 61 67 61 64 60 58 

* 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 

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 


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17Commenters 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. 

18The 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. 

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.’’ 

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. 

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 


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19NOX emissions can convert to visibility 

impairing nitrates in the atmosphere. 

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 noninterference 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. 

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 


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20Meteorology is not used directly for the 

emissions inventory approach that EPA used as the 

basis of its technical analysis. 

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 populationweighted 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 


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21Tennessee 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. 

22As 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 landwater interface. May 1st through September 30th 

was modeled using a 12-km modeling grid that 

covered the Eastern U.S. 

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. 

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 noninterference 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). 

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 


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23The 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). 

24See 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. 

25EPA 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.’’ 

26See ‘‘The Safer Affordable Fuel-Efficient 

(SAFE) Vehicles Rule for Model Years 2021–2026 

Passenger Cars and Light Trucks,’’ 85 FR 24174 

(April 30, 2020). 

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. 

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

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). 

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. 


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27The commenter’s phrase ‘‘2016 NEI’’ appears to 

refer to the 2016v1 emissions modeling platform 

produced by the National Emissions Inventory 

Collaborative. 

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. 

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 noninterference 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 noninterference 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 


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28This comment was received in docket EPA– 

R04–OAR–2019–0619 only. 

29The 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. 

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. 

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 CrossState 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. 

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 


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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. 

31See 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). 

32See 86 FR 23054 at 23075, 23164 (April 30, 

2021). 

33From 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.azure

websites.net/Files/Release_notes.v7.10.txt 

34Figure 1: Model-predicted 2023 maximum 

daily 8-hour ozone concentrations (ppb) for June 20 

from CAMX v7beta6 model runs without SAT (top) 

Continued 

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. 

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. 

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). 

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


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and with STA (bottom); both maps use the same 0 

to 80 ppb scale for depicting concentrations. 

35See 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. 

36See, e.g., White House signing statement at 

https://www.whitehouse.gov/briefing-room/ 

statements-releases/2021/06/30/bills-signed-s-j-res13-s-j-res-14-s-j-res-15/. 

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. 

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 noninterference 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. 

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 


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37National 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). 38See, 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). 

39See, 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.’’). 

40EPA 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. 

41Available at https://www.epa.gov/sites/ 

production/files/2017-07/documents/ei_guidance_

may_2017_final_rev.pdf. 

42See 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.’’ 

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

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

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

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 


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43Except 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. 

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. 

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-airand-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 


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Federal Register / Vol. 86, No. 156 / Tuesday, August 17, 2021 / Rules and Regulations 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 

■ 1. The authority citation for part 52 

continues to read as follows: 

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

Subpart RR—Tennessee 

■ 2. Section 52.2220 is amended by: 

■ a. In paragraph (c): 

■ 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 

■ ii. In Table 5, under the heading 

‘‘Article II. Standards for Operation,’’ 

removing the entry for ‘‘Regulation No. 

8—Regulation of Emissions from LightDuty Motor Vehicles through Mandatory 

Vehicle Inspection and Maintenance 

Program’’ in its entirety. 

■ b. In paragraph (e), in the table, 

revising the entry for ‘‘Attainment 

Demonstrations for Early Action 

Compact Areas’’. 

The revision reads as follows: 

§ 52.222052 Identification of plan. 

* * * * * 

(e) * * * 

EPA–APPROVED TENNESSEE NON–REGULATORY PROVISIONS

Name of nonregulatory SIP 

provision 

Applicable geographic or 

nonattainment area 

State effective 

date 

EPA approval 

date Explanation 

*******

Attainment Demonstrations 

for Early Action Compact 

Areas.

Chattanooga, Nashville, 

and Tri-Cities Early Action Compact Areas.

12/31/04 8/17/2021 With the exception of Tennessee Regulation Chapter 1200–3–29 and Nashville-Davidson County 

Regulation No. 8, with a State effective date of 2/ 

26/2020. 

*******

[FR Doc. 2021–17214 Filed 8–16–21; 8:45 am] 

BILLING CODE 6560–50–P 


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