Document ID: EPA-R04-OAR-2019-0618-0171
Agency: epa
Document Type: Proposed Rule
Title: Air Quality State Implementation Plans; Approvals and Promulgations: Tennessee; Removal of Vehicle I/M Program; Middle Tennessee Area and Hamilton County
Posted Date: 2021-04-22T04:00Z

[Federal Register Volume 86, Number 76 (Thursday, April 22, 2021)]
[Proposed Rules]
[Pages 21248-21254]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2021-08320]

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 52

[EPA-R04-OAR-2019-0618 and EPA-R04-OAR-2019-0619; FRL-10022-87-Region 
4]

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

AGENCY: Environmental Protection Agency (EPA).

ACTION: Supplemental notice of proposed rulemaking.

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SUMMARY: Through this supplemental notice of proposed rulemaking 
(``supplemental proposal'' or ``SNPRM''), the Environmental Protection 
Agency (EPA) is seeking public comment on the Agency's additional and 
clarified technical rationale related to the proposed approval of 
Tennessee's February 26, 2020, state implementation plan (SIP) 
revisions requesting 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. Specifically, 
EPA proposes to affirm that the Hamilton County and Middle Tennessee 
areas would continue to attain and maintain the national ambient air 
quality standards (NAAQS or standards) 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. EPA is further proposing to 
conclude that the 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 Clean Air Act (CAA or Act) and 
providing additional information related to that conclusion. EPA is now 
taking comment on the use of this comparison and additional information 
in this supplemental proposal.

DATES: Written comments must be received on or before May 24, 2021.

ADDRESSES: Submit your comments, identified by Docket ID No. EPA-R04-
OAR-2019-0618 (Middle Tennessee Area) or EPA-R04-OAR-2019-0619 
(Hamilton County), at www.regulations.gov. Follow the online 
instructions for submitting comments. Once submitted, comments cannot 
be edited or removed from Regulations.gov. EPA may publish any comment 
received to its public dockets. Do not submit electronically any 
information you consider to be Confidential Business Information (CBI) 
or other information whose disclosure is restricted by statute. 
Multimedia submissions (audio, video, etc.) must be accompanied by a 
written comment. The written comment is considered the official comment 
and should include discussion of all points you wish to make. EPA will 
generally not consider comments or comment contents located outside of 
the primary submission (i.e., on the web, cloud, or other file sharing 
system). For additional submission methods, the full EPA public comment 
policy, information about CBI or multimedia submissions, and general 
guidance on making effective comments, please visit www2.epa.gov/dockets/commenting-epa-dockets.

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:

[[Page 21249]]

I. Background for This Supplemental Proposal

    EPA published notices of proposed rulemaking (NPRMs) on June 8, 
2020, and June 11, 2020, responding to Tennessee's February 26, 2020, 
SIP revision requests \1\ that EPA approve removal of the I/M program 
\2\ from the Tennessee SIP for Hamilton County and the Middle Tennessee 
Area, respectively. Notably, Tennessee requested that the Tennessee Air 
Pollution Control Regulations (TAPCR) 1200-03-29 and Davidson County's 
Regulation 8 be removed from the Tennessee SIP.\3\ See 85 FR 35037 and 
85 FR 35607 for additional background. 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 
satisfies section 110(l) of the Clean Air Act (CAA) (i.e., will not 
interfere with any applicable requirement concerning attainment of any 
NAAQS and reasonable further progress, or any applicable requirements 
of the CAA). Comments closed on the NPRMs on July 8, 2020, and July 13, 
2020, respectively.\4\
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    \1\ EPA officially received Tennessee's I/M SIP revisions on 
February 27, 2020.
    \2\ Tennessee requested that EPA remove the requirements for the 
Middle Tennessee Area and Hamilton County to implement an I/M 
program as part of the Early Action Compact (EAC) that was approved 
by EPA into the non-regulatory portion of the Tennessee SIP on 
August 26, 2005. See 70 FR 50199. With respect to the Middle 
Tennessee Area, the I/M program was identified in the EAC as an 
existing control strategy in the SIP.
    \3\ Tenn. Code Ann. Sec.  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 supplemental proposal assumes that no I/M 
program will be implemented in the Middle Tennessee Area and 
Hamilton County. However, this proposed action does not preclude 
local I/M programs from being retained at a local level outside of 
the SIP.
    \4\ On January 19, 2021, former EPA Region 4 Administrator Mary 
Walker signed a document, which EPA posted to its website at https://www.epa.gov/sips-tn/epa-approval-tennessees-requests-remove-inspection-and-maintenance-im-program-tennessee. EPA noted in that 
posting ``Notwithstanding the fact that the EPA is posting a pre-
publication version, the final rule will not be promulgated until 
published in the Federal Register.'' EPA will not publish that 
document in the Federal Register; therefore, it will not result in a 
final rule.
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II. CAA Section 110(l) Analysis

    EPA is clarifying 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 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. EPA's proposed finding that these removals satisfy CAA 
section 110(l) is based on the technical analyses presented below, 
which are consistent with and provide additional support for the 
proposed conclusions set forth in the June 2020 NPRMs.
    EPA's CAA section 110(l) non-interference demonstration supporting 
its proposed 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 CO, the 
criteria pollutants addressed by I/M programs.\5\ 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 \6\ 
for ozone formation, EPA also evaluated VOC emissions to be 
environmentally conservative.
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    \5\ The total suite of CAA criteria pollutants are ozone 
(through the precursors NOX and VOCs), CO, PM (and its 
precursors--NOX, VOCs, ammonia, and SO2), 
lead, SO2, and NO2.
    \6\ The term ``NOX limited'' means that changes in 
anthropogenic VOC emissions have little effect on ozone formation. 
Control of NOX and VOC are generally considered the most 
important components of an ozone control strategy, and 
NOX and VOC make up the largest controllable contribution 
to ambient ozone formation. However, Tennessee has shown a greater 
sensitivity of ground-level ozone to NOX controls rather 
than VOC controls. This is due to high biogenic VOC emissions 
compared to anthropogenic VOC emissions in Tennessee. Therefore, 
implemented control measures have focused on the control of 
NOX emissions.
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    EPA is using 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. Tennessee chose 2022 as the future year for 
the State's non-interference demonstrations.\7\ 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.\8\ 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 is comparing 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 
proposing to conclude that these analyses, as described below, provide 
further support for the conclusions set forth in the June 2020 NPRMs. 
CAA section 110(l) demonstrations are case-specific and, in the case of 
the Tennessee I/M SIP revisions, modeling

[[Page 21250]]

is not required to demonstrate non-interference.
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    \7\ EPA notes that Tennessee did an analysis of emissions 
between 2022 and 2030 without I/M to determine the potential impact 
of on 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 proposed rulemaking as 
weight of evidence.
    \8\ 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. See EPA's July 2014 ``Policy Guidance on the Use of 
MOVES2014 for State Implementation Plan Development, Transportation 
Conformity, and Other Purposes,'' available at https://nepis.epa.gov/Exe/ZyPDF.cgi?Dockey=P100K4EB.pdf. MOVES2014b was the 
latest version available at the time of Tennessee's SIP revision. 
See 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),'' 
available at https://www.epa.gov/sites/production/files/2020-11/documents/420b20044_0.pdf (noting that ``[s]tates should use the 
latest version of MOVES that is available at the time that a SIP is 
developed.'').
    \9\ Design values are how EPA measures compliance with the 
NAAQS.
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A. Middle Tennessee Area

    The Middle Tennessee Area is currently in attainment with all 
NAAQS.\10\ As presented in Table 1, past design values (i.e., prior to 
October 1, 2015) have demonstrated attainment of the 2008 8-hour ozone 
NAAQS (i.e., the applicable NAAQS at that time), and recent design 
values have demonstrated attainment of the 2015 8-hour ozone NAAQS in 
the Middle Tennessee Area.
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    \10\ As mentioned in the June 8, 2020, NPRM, the current design 
values in the Middle Tennessee Area for PM, NO2, lead and 
SO2 are attaining the NAAQS. In fact, the Middle 
Tennessee Area has never been designated nonattainment for PM, 
NO2, lead, or SO2. The increases in 
NOX and VOC emissions without the I/M program in 2022 in 
comparison to with the I/M program in 2022 are not expected to cause 
a concern for PM, NO2, lead and SO2 compliance 
in the Middle Tennessee Area. As discussed more in this notice, no 
reductions or emissions benefits are attributable to the I/M program 
for PM, lead, and SO2 in the Middle Tennessee Area, and 
the total emissions increases in NOX (of which 
NO2 is a component) in 2022 without the program is less 
than the total emissions in 2014.

                         Table 1--Middle Tennessee Area Ozone Monitor Design Values ***
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                                                     Ozone design value, parts per billion (ppb)
             Site name             -----------------------------------------------------------------------------
                                     2012-2014    2013-2015    2014-2016    2015-2017    2016-2018    2017-2019
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Trinity Lane, Davidson County.....          (*)          (*)           66        ** 65           66           65
Percy Priest, Davidson County.....           70           65           67           64           67           65
Rockland Recreation Area, Sumner             72           67           67           66           66           66
 County...........................
Fairview Middle School, Williamson           66           62           61           60           60           60
 County...........................
Cedars of Lebanon State Park,                67           62           64           63          (*)          (*)
 Wilson County....................
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* No valid design value due to incomplete data. The Cedars of Lebanon site had incomplete data in 2018 because
  there was an issue following the installation of a new monitoring shelter, and TDEC invalidated data collected
  before the issue was corrected. The East Health/Trinity Lane site had incomplete data in 2013.
** In the June 11, 2020, NPRM (85 FR 35607), EPA inadvertently stated that the 2015-2017 design value was 66
  ppb. The correct value is 65 ppb.
*** The Middle Tennessee Area was in attainment with the most stringent ozone NAAQS effective during the time
  period of the design value. 2012-2014 and 2013-2015 design values were attaining the 2008 8-hour ozone NAAQS
  of 0.075 parts per million (ppm). 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 after this date attained the 2015 8-hour ozone standard.

    Also, design values for Tennessee for the 1-hour (see Table 2) and 
8-hour (see Table 3) CO NAAQS in 2019 were 1.8 ppm and 1.6 ppm, 
respectively, which are less than 20 percent of the CO NAAQS for both 
the 1-hour and 8-hour standards.

                                             Table 2--Middle Tennessee Area CO Monitor 1-Hour Design Values
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                                                                                              CO 1-hr design value, ppm **
                          Site name                           ------------------------------------------------------------------------------------------
                                                                2012-2013    2013-2014    2014-2015    2015-2016    2016-2017    2017-2018    2018-2019
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Alabama Ave. Station, Shelby County..........................          2.4          2.4          1.9          1.9          1.4          (*)          (*)
Great Smoky Mountains NP--Look Rock, Blount County...........          (*)          (*)          0.3          2.2          2.2          0.3          1.2
Memphis NCORE site, Shelby County............................          1.3          1.3          1.6          1.6          1.0          1.0          1.0
Broadway, Davidson County....................................          1.9          1.6          (*)          (*)          (*)          (*)          (*)
Near Road, Davidson County...................................          (*)          (*)          1.7          1.7          1.9          1.9          1.8
Near Road Site at Southwest Tennessee Community College,               (*)          (*)          4.5          4.5          1.2          1.6          1.6
 Shelby County...............................................
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* Data are not available for all monitors and years due to CO monitor startups and shutdowns during this time period.
** The level of the 1971 1-hour NAAQS for CO is 35 ppm not to be exceeded more than once per year. The design value is evaluated over a 2-year period.
  Specifically, the design value is the higher of each year's annual second maximum, non-overlapping 1-hour average. Only valid design values are shown.

                                             Table 3--Middle Tennessee Area CO Monitor 8-Hour Design Values
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                                                                                              CO 8-hr design value, ppm **
                          Site name                           ------------------------------------------------------------------------------------------
                                                                2012-2013    2013-2014    2014-2015    2015-2016    2016-2017    2017-2018    2018-2019
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Alabama Ave. Station, Shelby County..........................          1.9          1.9          1.5          1.5          1.2          (*)          (*)
Great Smoky Mountains NP--Look Rock, Blount County...........          (*)          0.2          0.3          1.2          1.2          0.3          0.6
Memphis NCORE site, Shelby County............................          0.8          0.8          0.9          0.9          0.7          0.9          0.9
Broadway, Davidson County....................................          1.5          1.2          (*)          (*)          (*)          (*)          (*)
Near Road, Davidson County...................................          (*)          1.2          1.4          1.5          1.5          1.6          1.6
Near Road Site at Southwest Tennessee Community College,               (*)          0.6          2.0          2.0          0.7          0.9          0.9
 Shelby County...............................................
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* Data are not available for all monitors and years due to CO monitor startups and shutdowns during this time period.

[[Page 21251]]

 
** The level of the 1971 8-hour NAAQS for CO is 9 ppm not to be exceeded more than once per year. The design value is evaluated over a two-year period.
  Specifically, the design value is the higher of each year's annual second maximum, non-overlapping 8-hour average. Only valid design values are shown.

    Monitoring data for 2020 are not yet certified, but preliminary 
data remain consistent with attainment of the ozone and CO NAAQS.
    To support a demonstration of non-interference for the Middle 
Tennessee Area, EPA is using 2014 as an attainment base year \11\ and 
comparing the total emissions of NOX, VOC, and CO to the 
total emissions of these pollutants in 2022, the first full year in 
which the I/M program in the Middle Tennessee Area is expected to no 
longer exist. EPA chose 2014 because the 2014 point, non-road, and non-
point data provided in Tennessee's February 26, 2020, submissions were 
the most current data available to the State at the time of the 
development of these SIP revisions. The mobile emissions were generated 
utilizing MOVES2014b, the applicable mobile emissions model at the time 
of the development of the SIP revision. For consistent comparisons, EPA 
obtained the 2014 mobile emissions submitted by Tennessee from EPA's 
Emissions Inventory System (EIS). Table 4 provides a summary for the 
Middle Tennessee Area of the total emissions for NOX, VOC, 
and CO in 2014; total emissions for NOX, VOC, and CO in 2022 
with the I/M program; and total emissions for NOX, VOC, and 
CO in 2022 without the I/M program.
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    \11\ As shown in Table 1 above, 2014 is included as one of the 
years associated with attaining design values for the 2008 8-hour 
ozone NAAQS (the applicable NAAQS in 2014). Although the 2014 4th 
highest daily maximum 8-hour ozone concentration is 71 ppb (i.e., 
higher than the level of the 2015 8-hour ozone NAAQS) at the Percy 
Priest Dam monitor, EPA believes that 2014 is an acceptable base 
year given the magnitude of the NOX and VOC emissions 
reductions from 2014 to 2022 and the fact that the 2014 4th max was 
only one ppb higher than the level of the 2015 8-hour ozone 
standard. https://www.epa.gov/outdoor-air-quality-data. EPA also 
notes that the 2015 8-hour ozone NAAQS was not in effect until 
October 1, 2015.

                                             Table 4--Middle Tennessee Area Emissions (Tons per Year (tpy))
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                                                        2014 Emissions             2022 Projected emissions with I/M   2022 Projected emissions  without
                                             ------------------------------------------------------------------------                 I/M
                   Sector                                                                                            -----------------------------------
                                                  NOX         VOC         CO          NOX         VOC         CO          NOX         VOC         CO
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Onroad......................................      27,499      12,497     135,844      11,309       4,780      71,816      11,788       5,373      82,184
Point.......................................       8,040       3,803       2,568       4,455       3,867       2,696       4,455       3,867       2,696
Nonroad.....................................       8,339       5,638      56,497       5,413       3,451      49,105       5,413       3,451      49,105
Non-Point...................................       3,702      19,716      41,375       3,504      22,690      45,833       3,504      22,690      45,833
                                             -----------------------------------------------------------------------------------------------------------
    Total...................................      47,580      41,654     236,284      24,681      34,788     169,450      25,160      35,382     179,818
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Percent reduction from 2014 emissions:                                                                                     47.1%       15.1%       23.9%
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    As stated in EPA's June 11, 2020, NPRM, for 2022, the removal of 
the I/M program accounts for a small increase in NOX and VOC 
on-road emissions. The difference in NOX emissions in 2022, 
with and without the I/M program, is 479 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.
    Because 2022 total emissions without the I/M program are projected 
to be less than the total 2014 emissions, EPA proposes to conclude that 
removal of the I/M program in the Middle Tennessee Area will not 
interfere with attainment or maintenance of the NAAQS or any other 
applicable CAA requirements. Additionally, as shown in Table 1, the 
highest ozone design value associated with 2014 is 6 ppb above the most 
recently available ozone design value for 2017-2019, thereby providing 
an additional buffer, and the 2017-2019 ozone design value is at least 
4 ppb below the level of the 2015 8-hour ozone NAAQS of 70 ppb. EPA is 
proposing to conclude that it is reasonable to expect emissions that 
are 22,420 tpy less than 2014 NOX emissions and 6,272 tpy 
less than 2014 VOC emissions would not cause ozone levels to exceed the 
current 2015 8-hour ozone NAAQS. Also, EPA is proposing to conclude 
that it is reasonable to expect that emissions that are 56,466 tpy less 
than 2014 CO emissions would not cause CO levels to exceed either the 
1-hour or 8-hour CO NAAQS.

B. Hamilton County

    Hamilton County is currently in attainment with all NAAQS.\12\ As 
presented in Table 5, past design values (i.e., prior to October 1, 
2015) have demonstrated attainment of the 2008 8-hour ozone NAAQS 
(i.e., the applicable NAAQS at that time), and recent design values 
have demonstrated attainment of the 2015 8-hour ozone NAAQS in Hamilton 
County.
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    \12\ As mentioned in the June 8, 2020, NPRM, the current design 
values in Hamilton County for PM, NO2, lead, and 
SO2 are attaining the NAAQS. In fact, Hamilton County has 
never been designated nonattainment for NO2, lead, or 
SO2. Hamilton County was previously designated 
nonattainment for the 1997 p.m. NAAQS but has since attained that 
NAAQS and is still in compliance. The increases in NOX 
and VOC emissions without the I/M program in 2022 in comparison to 
with the I/M program in 2022 are not expected to cause a concern for 
PM, NO2, lead and SO2 compliance in Hamilton 
County. As discussed more in this notice, no reductions or emissions 
benefits are attributable to the I/M program for PM, lead, and 
SO2 in Hamilton County, and the total emissions increases 
in NOX (of which NO2 is a component) in 2022 
without the program is less than the total emissions in 2014.

[[Page 21252]]

                              Table 5--Hamilton County Ozone Monitor Design Values
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                                                              Ozone design value, ppb *
             Site name             -----------------------------------------------------------------------------
                                     2012-2014    2013-2015    2014-2016    2015-2017    2016-2018    2017-2019
----------------------------------------------------------------------------------------------------------------
Eastside Utility..................           69           66           68           67           66           64
Soddy Daisy.......................           67           64           65           65           64           64
----------------------------------------------------------------------------------------------------------------
* Hamilton County was in attainment with the most stringent ozone NAAQS effective during the time period of the
  design value. 2012-2014 and 2013-2015 design values were attaining the 2008 8-hour ozone NAAQS of 0.075 ppm.
  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 after this date attained the 2015 standard.

    The Chattanooga Metropolitan Statistical Area (of which Hamilton 
County is a part) is not required to operate a CO monitor, and there is 
no historical CO monitoring data in Hamilton County. The highest CO 
design values in Tennessee during 2018-2019 for the 1-hour and 8-hour 
CO NAAQS were both measured at the Nashville Near Road site, and were 
1.6 ppm (see Table 2 above) and 1.8 ppm (see Table 3 above), 
respectively, which are less than 20 percent of the CO NAAQS for both 
the 1-hour and 8-hour standards.
    To support a demonstration of non-interference for Hamilton County, 
EPA is using 2014 as an attainment base year \13\ and comparing the 
total emissions of NOX, VOC, and CO to the total emissions 
of these pollutants in 2022, the first full year in which the I/M 
program in Hamilton County is expected to no longer exist. EPA chose 
2014 because the 2014 point, non-road, and non-point data provided in 
Tennessee's February 26, 2020, submissions, were the most current data 
available to the State at the time of the development of these SIP 
revisions. The mobile emissions were generated utilizing MOVES2014b, 
the applicable mobile emissions model at the time of the development of 
the SIP revision. For consistent comparisons, EPA obtained the 2014 
mobile emissions submitted by Tennessee from EPA's EIS. Table 6 
provides a summary for Hamilton County of the total emissions for 
NOX, VOC, and CO in 2014; total emissions for 
NOX, VOC, and CO in 2022 with the I/M program; and total 
emissions for NOX, VOC, and CO in 2022 without the I/M 
program.
---------------------------------------------------------------------------

    \13\ As shown in Table 5 above, 2014 is one of the years 
associated with attaining design values for the 2008 8-hour ozone 
NAAQS of 0.075 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.

                                                         Table 6--Hamilton County Area Emissions
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                        2014 Emissions             2022 Projected emissions with I/M   2022 Projected emissions  without
                                             ------------------------------------------------------------------------                 I/M
                   Sector                                                                                            -----------------------------------
                                                  NOX         VOC         CO          NOX         VOC         CO          NOX         VOC         CO
--------------------------------------------------------------------------------------------------------------------------------------------------------
Onroad......................................       6,659       3,173      35,539       4,613       2,127      23,875       4,712       2,273      26,854
Point.......................................       1,024         664         458       1,314         825         566       1,314         825         566
Nonroad.....................................       3,252       1,587      13,594       2,220         935      11,600       2,220         935      11,600
Non-Point...................................       2,037       5,212       7,038       1,220       5,744       7,007       1,220       5,777       7,007
                                             -----------------------------------------------------------------------------------------------------------
    Total...................................      12,972      10,636      56,629       9,367       9,632      43,049       9,467       9,778      46,028
--------------------------------------------------------------------------------------------------------------------------------------------------------
Percent reduction from 2014 emissions:                                                                                     27.0%        8.1%       18.7%
--------------------------------------------------------------------------------------------------------------------------------------------------------

    As stated in the June 8, 2020, NPRM, for 2022, the removal of the 
I/M program accounts for a small increase in NOX and VOC on-
road emissions. 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.
    Because 2022 total emissions without the I/M program are less than 
total 2014 base year emissions, EPA proposes to conclude that removal 
of the I/M program in Hamilton County will not interfere with 
attainment or maintenance of the NAAQS or any other applicable 
requirement of the CAA. Additionally, as shown in Table 5, the highest 
ozone design value associated with 2014 is 5 ppb above the most 
recently available ozone design value for 2017-2019, thereby providing 
an additional buffer, and the 2017-2019 ozone design value is 6 ppb 
below the level of the 2015 8-hour ozone NAAQS of 70 ppb. EPA is 
proposing to conclude that it is reasonable to expect emissions that 
are 3,505 tpy less than 2014 NOX emissions and 858 tpy less 
than 2014 VOC emissions would not cause ozone levels to exceed the 
current 2015 8-hour ozone NAAQS. Also, EPA is proposing to conclude 
that it is reasonable to expect that emissions that are 10,061 tpy less 
than 2014 CO emissions would not cause CO levels to exceed either the 
1-hour or 8-hour CO NAAQS.

C. Interstate Ozone Transport

    EPA proposes to conclude that the changes that would be approved by 
EPA in this action do not interfere with other states' ability to 
attain and maintain the 2008 ozone NAAQS under the good neighbor 
provision, CAA section 110(a)(2)(D)(i)(I). EPA has previously found 
that the 2016 Cross-State Air Pollution Rule (CSAPR) Update fully 
resolved Tennessee's good neighbor (or

[[Page 21253]]

``transport'') obligations for the 2008 ozone NAAQS. The CSAPR Update 
addresses NOX pollution transported to other states that 
significantly contributes to nonattainment or interferes with 
maintenance of the 2008 ozone NAAQS.\14\ 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 for most covered states, EPA found the 
CSAPR Update may only partially address the covered states' good 
neighbor obligations, EPA found the rule fully addresses Tennessee's 
good neighbor obligation for this NAAQS. See 81 FR 74504, 74540. 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.
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    \14\ The CSAPR Update is a rule that followed the original CSAPR 
rulemaking in 2011. CSAPR requires certain states in the eastern 
half of the U.S. to improve air quality by reducing power plant 
emissions of NOX and SO2 that cross state 
lines and contribute to smog and soot pollution in downwind states. 
On September 7, 2016, EPA revised the CSAPR ozone season 
NOX program by finalizing an update to CSAPR for the 2008 
ozone National Ambient Air Quality Standards, known as the CSAPR 
Update. The CSAPR Update ozone season NOX program was 
designed to largely replace the original CSAPR ozone season 
NOX program starting on May 1, 2017, and further reduce 
summertime NOX emissions from power plants in the eastern 
U.S.
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    The CSAPR Update was reviewed and generally upheld in Wisconsin v. 
EPA, 983 F.3d 303 (D.C. Cir. 2019). The D.C. Circuit 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. 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 
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. As 
discussed in the sections above, in this supplemental notice, EPA has 
analyzed the impacts of removing the I/M program in the Middle 
Tennessee Area and Hamilton County and proposes to find 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 
these areas.\15\ 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 for these 
areas.
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    \15\ 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.
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    On October 30, 2020, in the notice of proposed rulemaking for the 
Revised CSAPR Update, which addresses the Wisconsin remand, 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.\16\ 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).\17\
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    \16\ See 85 FR 68964, 68981. The results of this modeling are 
included in a spreadsheet in the docket 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).
    \17\ On March 15, 2022, Administrator Michael S. Regan signed 
the final Revised CSAPR Update. The final action relies on the same 
modeling conducted for the proposed rulemaking and described here. 
See https://www.epa.gov/csapr/revised-cross-state-air-pollution-rule-update.
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    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 supplemental proposed 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.

III. Incorporation by Reference

    In this document, EPA is proposing to include in a final EPA rule 
amended regulatory text that includes incorporation by reference. EPA 
is proposing to remove Chapter 1200-3-29--``Light Duty Vehicle 
Inspection and Maintenance'' located in Table 1--EPA Approved Tennessee 
Regulations, and Regulation No. 8--``Regulation of Emissions from 
Light-Duty Motor Vehicles through Mandatory Vehicle Inspection and 
Maintenance Program,'' located in Table 5--EPA Approved Nashville-
Davidson County, Regulations from the Tennessee SIP, which is 
incorporated by reference in accordance with the requirements of 1 CFR 
51.5. EPA has made and will continue to make the SIP generally 
available through www.regulations.gov and at the EPA Region 4 Office 
(please contact the person identified in the ``For Further Information 
Contact'' section of this preamble for more information).

IV. Supplemental Proposed Actions

    In its June 2020 NPRMs, EPA originally proposed to approve 
Tennessee's February 26, 2020, SIP revisions to remove the I/M programs 
for Hamilton County and the Middle Tennessee Area from Tennessee's SIP. 
EPA continues to propose to find that the removal of the I/M program 
requirements for Hamilton County and Middle Tennessee are consistent 
with CAA section 110(l). Additionally, EPA continues to propose to 
approve the removal of the I/M requirements for Hamilton County and the 
Middle Tennessee Area from the Tennessee SIP. However, through this 
SNPRM, EPA is proposing to rely on an additional and clarified 
technical rationale related to the proposed approval of Tennessee's 
February 26, 2020 SIP revisions. Specifically, EPA proposes to rely on 
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 and further affirms that 
both areas would continue to attain and maintain the other NAAQS after 
removal of the I/M program. EPA is further proposing to conclude that 
the proposed 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 and providing information related to that 
conclusion. EPA is requesting comment on the use of additional and 
clarified technical analysis in this supplemental proposal.

V. Statutory and Executive Order Reviews

    Under the CAA, the Administrator is required to approve SIP 
submissions

[[Page 21254]]

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 propose to 
approve state law as meeting Federal requirements and do not impose 
additional requirements beyond those imposed by state law. For that 
reason, these proposed actions:
     Are not significant regulatory actions subject to review 
by the Office of Management and Budget under Executive Orders 12866 (58 
FR 51735, October 4, 1993) and 13563 (76 FR 3821, January 21, 2011);
     Do not impose an information collection burden under the 
provisions of the Paperwork Reduction Act (44 U.S.C. 3501 et seq.);
     Are certified as not having a significant economic impact 
on a substantial number of small entities under the Regulatory 
Flexibility Act (5 U.S.C. 601 et seq.);
     Do not contain any unfunded mandate or significantly or 
uniquely affect small governments, as described in the Unfunded 
Mandates Reform Act of 1995 (Pub. L. 104-4);
     Do not have Federalism implications as specified in 
Executive Order 13132 (64 FR 43255, August 10, 1999);
     Are not economically significant regulatory actions based 
on health or safety risks subject to Executive Order 13045 (62 FR 
19885, April 23, 1997);
     Are not significant regulatory actions subject to 
Executive Order 13211 (66 FR 28355, May 22, 2001);
     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 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.

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.

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

    Dated: April 13, 2021.
John Blevins,
Acting Regional Administrator, Region 4.
[FR Doc. 2021-08320 Filed 4-21-21; 8:45 am]
BILLING CODE 6560-50-P