Document ID: EPA-R04-OAR-2020-0482-0008
Agency: epa
Document Type: Rule
Title: Air Quality Designation: Tennessee: Redesignation of the Sumner County  2010 Sulfur Dioxide Unclassifiable Area
Posted Date: 2021-05-25T04:00Z

[Federal Register Volume 86, Number 99 (Tuesday, May 25, 2021)]
[Rules and Regulations]
[Pages 27981-27984]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2021-10983]

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 81

[EPA-R04-OAR-2020-0482; FRL-10024-20-Region 4]

Air Quality Designation; TN: Redesignation of the Sumner County 
2010 Sulfur Dioxide Unclassifiable Area

AGENCY: Environmental Protection Agency (EPA).

ACTION: Final rule.

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SUMMARY: The Environmental Protection Agency (EPA) is approving a 
submission by the State of Tennessee, through the Tennessee Department 
of Environment and Conservation (TDEC), on September 29, 2020, to 
redesignate the Sumner County, Tennessee, unclassifiable area 
(hereinafter referred to as the ``Sumner County Area'' or ``Area'') to 
attainment/unclassifiable for the 2010 1-hour primary sulfur dioxide 
(SO2) national ambient air quality standard (hereinafter 
referred to as the 2010 SO2 1-hour NAAQS). EPA now has 
sufficient information to determine that the Sumner County Area is 
attaining the 2010 1-hour SO2 NAAQS and is approving the 
State's request and redesignating the Area to attainment/unclassifiable 
for the 2010 1-hour SO2 NAAQS.

DATES: This rule is effective June 24, 2021.

ADDRESSES: EPA has established a docket for this action under Docket 
Identification No. EPA-R04-OAR-2020-0482. All documents in the docket 
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 are 
available either electronically through 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

[[Page 27982]]

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: Evan Adams, Air Regulatory Management 
Section, Air Planning and Implementation Branch, Air and Radiation 
Division, U.S. Environmental Protection Agency, Region 4, 61 Forsyth 
Street SW, Atlanta, Georgia 30303-8960. Mr. Adams can be reached by 
telephone at (404) 562-9009 or via electronic mail at 
adams.evan@epa.gov.

SUPPLEMENTARY INFORMATION:

I. Background

    The Clean Air Act (CAA or Act) establishes a process for air 
quality management through the establishment and implementation of the 
national ambient air quality standards (NAAQS). On June 2, 2010, EPA 
revised the primary SO2 NAAQS, establishing a new 1-hour 
SO2 standard of 75 parts per billion (ppb). See 75 FR 35520 
(June 22, 2010).\1\ After the promulgation of a new or revised NAAQS, 
EPA is required to designate all areas of the country, pursuant to 
section 107(d)(1)-(2) of the CAA. For the 2010 1-hour SO2 
NAAQS, designations were based on EPA's application of the nationwide 
analytical approach to, and technical assessment of, the weight of 
evidence for each area, including but not limited to available air 
quality monitoring data and air quality modeling results. In advance of 
designating the Sumner County Area, EPA issued updated designations 
guidance through a March 20, 2015, memorandum from Stephen D. Page, 
Director, U.S. EPA, Office of Air Quality Planning and Standards, to 
Air Division Directors, U.S. EPA Regions 1-10, titled ``Updated 
Guidance for Area Designations for the 2010 Primary Sulfur Dioxide 
National Ambient Air Quality Standard,'' which contains the factors 
that EPA evaluated in determining the appropriate designations and 
associated boundaries when designating the Sumner County Area, 
including: (1) Air quality characterization via ambient monitoring or 
dispersion modeling results; (2) emissions-related data; (3) 
meteorology; (4) geography and topography; and (5) jurisdictional 
boundaries.2 3 The guidance also references EPA's non-
binding Monitoring Technical Assistance Document (Monitoring TAD) and 
Modeling Technical Assistance Document (Modeling TAD),\4\ which contain 
scientifically sound recommendations on how air agencies should conduct 
such monitoring or modeling.
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    \1\ On February 25, 2019 (effective April 17, 2019), based on a 
review of the full body of currently available scientific evidence 
and exposure/risk information, EPA issued a decision to retain the 
existing NAAQS for SO2. See 84 FR 9866.
    \2\ The 2015 memorandum is available at https://www.epa.gov/sites/production/files/2016-04/documents/20150320so2designations.pdf.
    \3\ This designation guidance has since been superseded by a 
July 22, 2016, designation guidance memorandum from Stephen D. Page, 
Director, U.S. EPA, Office of Air Quality Planning and Standards, to 
Regional Air Division Directors, U.S. EPA Regions 1-10. The 2016 
memorandum is available at https://www.epa.gov/sites/production/files/2016-07/documents/areadesign.pdf.
    \4\ ``Sulfur Dioxide (SO2) National Ambient Air 
Quality Standards Designations Modeling Technical Assistance 
Document,'' August 2016 draft, available at https://www.epa.gov/sites/production/files/2016-06/documents/so2modelingtad.pdf. Note, 
EPA released earlier drafts of this document in May 2013 and 
February 2016.
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    EPA completed the first set of initial area designations for the 
2010 1-hour SO2 NAAQS in 2013 (Round 1). Pursuant to a March 
2, 2015, consent decree and court-ordered schedule,\5\ EPA finalized a 
second set of initial area designations for the 2010 1-hour 
SO2 NAAQS in 2016 (Round 2). The March 2, 2015, consent 
decree identified the following emissions criteria such that EPA must 
designate, in Round 2, an area surrounding any stationary source which 
had: (a) Annual emissions in 2012 exceeding 16,000 tons of 
SO2, or (b) both an annual average emissions rate of at 
least 0.45 pounds of SO2 per one million British thermal 
units, according to EPA's Clean Air Markets Division Database, and 
annual emissions of at least 2,600 tons of SO2 in 2012. 
Sumner County, Tennessee, contained one source, Tennessee Valley 
Authority (TVA) Gallatin Fossil Plant (TVA Gallatin), that met these 
Round 2 criteria. EPA evaluated the Area, using the five factors 
identified previously, during the Round 2 designations. TVA Gallatin is 
a large Electric Generating Unit located in north central Tennessee in 
the southern portion of Sumner County, approximately five kilometers 
(km) southeast of the center of Gallatin, Tennessee. The facility was 
included in the list of facilities to be designated pursuant to the 
March 2, 2015, Consent Decree.6 7
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    \5\ See Sierra Club et. al. v. McCarthy, Civil Action No. 3:13-
cv-3953-SI (N.D. Cal.), and 79 FR 31325 (June 2, 2014).
    \6\ TVA Gallatin was also subject to EPA's 2015 Data 
Requirements Rule (DRR) for the 2010 SO2 1-hour NAAQS. 
See https://www.epa.gov/sites/production/files/2016-06/documents/tn.pdf for Tennessee's letter dated January 15, 2016, with the Data 
Requirements Rule (DRR) source list.
    \7\ In accordance with the DRR, 40 CFR part 51, subpart BB, 
through a letter dated June 7, 2016, Tennessee notified EPA that the 
State chose to characterize peak 1-hour SO2 
concentrations for TVA Gallatin using air quality dispersion 
modeling.
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    EPA's March 20, 2015, guidance specified the designation category 
definitions to be used in the Round 2 designations.\8\ EPA was unable 
to determine whether the Sumner County Area met the definition of a 
nonattainment area or the definition of an attainment area based on the 
available information at the time of the Round 2 designations. As a 
result, EPA designated the Sumner County Area as unclassifiable in the 
Round 2 designations published on July 12, 2016.\9\ The boundary for 
this designation was the jurisdictional boundary of Sumner County.\10\
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    \8\ Specifically, EPA defined a ``nonattainment'' area as an 
area that EPA has determined violates the 2010 1-hour SO2 
NAAQS based on the most recent three years of ambient air quality 
monitoring data or an appropriate modeling analysis, or that EPA has 
determined contributes to a violation in a nearby area; and defined 
an ``attainment'' area as an area that EPA has determined meets the 
2010 1-hour SO2 NAAQS and does not contribute to a 
violation of the NAAQS in a nearby area based on either: (a) The 
most recent 3 years of ambient air quality monitoring data from a 
monitoring network in an area that is sufficient to be compared to 
the NAAQS per EPA interpretations in the Monitoring TAD, or (b) an 
appropriate modeling analysis.
    \9\ See 81 FR 45039 (July 12, 2016), codified at 40 CFR 81.343.
    \10\ Detailed rationale, analyses, and other information 
supporting EPA's original Round 2 designation for this Area can be 
found in the intended and final Round 2 designation's TSD for 
Tennessee. This document, along with all other supporting materials 
for the original 2010 1-hour SO2 NAAQS designation for 
Sumner County, can be found on EPA's SO2 designations 
website. EPA SO2 designations website can be found at 
https://www.epa.gov/sulfur-dioxide-designations.
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    In support of this final redesignation action, EPA evaluated new 
modeling for the Sumner County Area provided by Tennessee and developed 
a new technical support document (TSD).\11\ On September 29, 2020, 
Tennessee submitted a request for EPA to redesignate the Sumner County 
Area to attainment/unclassifiable for the 2010 1-hour primary 
SO2 NAAQS based on air quality dispersion modeling showing 
that the Area is in compliance with the 2010 1-hour primary 
SO2 NAAQS.12 13 14

[[Page 27983]]

The updated modeling was performed using the current version of EPA's 
recommended dispersion model, AERMOD version 19191, with the most 
recent three years of actual SO2 emissions (2017-2019) from 
the TVA Gallatin facility and concurrent meteorology data.\15\
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    \11\ The TSD for this proposed action is included in the docket.
    \12\ The demonstration of attainment through air quality 
dispersion modeling requires an area to review and report annual 
SO2 emissions pursuant to DRR ongoing verification at 40 
CFR 51.1205(b). In its September 29, 2020, redesignation request 
letter, Tennessee also requested to terminate the section 51.1205(b) 
annual reporting requirement because the modeling analyses 
demonstrated a value of at least 50 percent below the 2010 1-hour 
SO2 NAAQS at all receptors. EPA will address the annual 
reporting termination request in a separate action which has no 
bearing on the final approval of the redesignation.
    \13\ See letter signed by Michelle Owenby, Director of TDEC's 
Division of Air Pollution Control, September 29, 2020, requesting 
that EPA redesignate Sumner County, Tennessee, to attainment/
unclassifiable for the 2010 1-hour SO2 NAAQS.
    \14\ EPA is redesignating the area to ``attainment/
unclassifiable'' because, as noted in the proposal, EPA reserves the 
``attainment'' category for when EPA redesignates a nonattainment 
area that has attained the relevant NAAQS and has an approved 
maintenance plan.
    \15\ The TSD included in the docket for this proposed 
redesignation action provides a detailed summary of Tennessee's 
modeling analysis and EPA's evaluation of the modeling. The modeling 
files are not included in the electronic docket for this action due 
to their nature, size, and incompatibility with the Federal Docket 
Management System. These files are available at the EPA Region 4 
office for review. To request these files, please contact the person 
listed in the notice under the section titled FOR FURTHER 
INFORMATION CONTACT.
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    After reviewing Tennessee's request under CAA section 107(d)(3)(D) 
and all available information, EPA has determined that the modeling 
provided by the State comports with EPA's current Modeling TAD and 
EPA's Guideline on Air Quality Models (40 CFR part 51 Appendix W) and 
is acceptable for assessing the attainment status of the Sumner County 
Area. The State's modeling indicates that the predicted maximum design 
value at any receptor in the modeling domain is 60.5 micrograms per 
cubic meter ([mu]g/m\3\), or 23.1 ppb. EPA's review confirms that the 
modeling results appropriately characterize the air quality in the 
Sumner County Area and that predicted ambient SO2 
concentrations are below the 2010 1-hour SO2 NAAQS of 196.4 
[mu]g/m\3\, or 75 ppb. Additionally, there is no evidence of monitored 
or modeled violations in the surrounding counties such that the source 
is contributing to any nearby area that does not meet the NAAQS.
    EPA is taking final action to approve Tennessee's redesignation 
request and is redesignating the entirety of Sumner County that was 
designated as unclassifiable in July 2016 to attainment/unclassifiable 
based on the currently available information that demonstrates 
attainment of the 2010 1-hour SO2 NAAQS.\16\ In a notice of 
proposed rulemaking (NPRM) published on March 5, 2021 (86 FR 12892), 
EPA proposed to approve the State's redesignation request. The details 
of Tennessee's submittal and the rationale for EPA's actions are 
further explained in the NPRM. Comments on the NPRM were due on or 
before April 5, 2021. EPA did not receive any adverse comments on the 
action.
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    \16\ For redesignations of unclassifiable areas, the necessary 
analysis is equivalent to what would be required in a designation in 
the first instance since EPA has not found the area to be attainment 
or nonattainment. In this first instance, the goal is to 
characterize existing ambient air quality. As such, it is 
appropriate to use actual emissions for estimating existing air 
quality. EPA's acceptance of modeling using actual emissions in this 
instance should not be construed to define what would be needed for 
a demonstration of attainment and maintenance for purposes of a 
redesignation of a nonattainment area to attainment.
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III. Final Action

    EPA is approving Tennessee's September 29, 2020, request to 
redesignate the Sumner County Area from unclassifiable to attainment/
unclassifiable for the 2010 1-hour SO2 NAAQS. EPA has 
reviewed the modeling provided by the State with its redesignation 
request and finds that it complies with EPA's current Modeling TAD and 
EPA's Guideline on Air Quality Models (40 CFR part 51 Appendix W) and 
is acceptable for assessing the attainment status of the Sumner County 
Area. This approval of the redesignation request changes the legal 
designation, found at 40 CFR part 81, of Sumner County from 
unclassifiable to attainment/unclassifiable for the 2010 1-hour 
SO2 NAAQS.

IV. Statutory and Executive Order Reviews

    Under the CAA, redesignation of an area to attainment/
unclassifiable is an action that affects the status of a geographical 
area and does not impose any additional regulatory requirements on 
sources beyond those imposed by state law. A redesignation to 
attainment/unclassifiable does not in and of itself create any new 
requirements, but rather results in the applicability of requirements 
contained in the CAA for areas that have been redesignated to 
attainment. Accordingly, this action merely redesignates an area to 
attainment/unclassifiable and does not impose additional requirements. 
For that reason, this action:
     Is not a significant regulatory action 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);
     Does not impose an information collection burden under the 
provisions of the Paperwork Reduction Act (44 U.S.C. 3501 et seq.);
     Is 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.);
     Does 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);
     Does not have Federalism implications as specified in 
Executive Order 13132 (64 FR 43255, August 10, 1999);
     Is not an economically significant regulatory action based 
on health or safety risks subject to Executive Order 13045 (62 FR 
19885, April 23, 1997);
     Is not a significant regulatory action subject to 
Executive Order 13211 (66 FR 28355, May 22, 2001);
     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 CAA; and
     Will not have disproportionate human health or 
environmental effects under Executive Order 12898 (59 FR 7629, February 
16, 1994).
    This final redesignation does not apply to 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. 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 July 26, 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

[[Page 27984]]

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 81

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

    Dated: May 17, 2021.
John Blevins,
Acting Regional Administrator, Region 4.

    For the reasons stated in the preamble, EPA amends 40 CFR part 81 
as follows:

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

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

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

0
2. In Sec.  81.343, the table titled ``Tennessee-2010 Sulfur Dioxide 
NAAQS (Primary)'' is amended by revising the entry for ``Sumner County, 
TN'' to read as follows:

Sec.  81.343  Tennessee.

* * * * *

                  Tennessee--2010 Sulfur Dioxide NAAQS
                                [Primary]
------------------------------------------------------------------------
                                              Designation
       Designated area       -------------------------------------------
                                     Date 1                 Type
------------------------------------------------------------------------
 
                              * * * * * * *
    Sumner County, TN \2\...  June 24, 2021.......  Attainment/
                                                     Unclassifiable.
Sumner County
 
                              * * * * * * *
------------------------------------------------------------------------
\1\ This date is April 9, 2018, unless otherwise noted.
\2\ Excludes Indian country located in each area, if any, unless
  otherwise specified.

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[FR Doc. 2021-10983 Filed 5-24-21; 8:45 am]
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