
[Federal Register Volume 82, Number 102 (Tuesday, May 30, 2017)]
[Proposed Rules]
[Pages 24621-24635]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2017-10905]


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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Parts 52 and 81

[EPA-R04-OAR-2017-0086; FRL- 9962-24-Region 4]


Air Plan Approval and Air Quality Designation; TN; Redesignation 
of the Knoxville 2006 24-Hour PM2.5 Nonattainment Area to Attainment

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.

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SUMMARY: On December 20, 2016, Tennessee, through the Tennessee 
Department of Environment and Conservation (TDEC), submitted a request 
for the Environmental Protection Agency (EPA) to redesignate the 
Knoxville-Sevierville-La Follette, TN fine particulate matter 
(PM2.5) nonattainment area (hereinafter referred to as the 
``Knoxville Area'' or ``Area'') to attainment for the 2006 24-hour 
PM2.5 national ambient air quality standards (NAAQS) and to 
approve a state implementation plan (SIP) revision containing a 
maintenance plan and a reasonably available control measures (RACM) 
determination for the Area. EPA is proposing to approve Tennessee's 
RACM determination for the Knoxville Area and incorporate it into the 
SIP; to approve Tennessee's plan for maintaining the 2006 24-hour

[[Page 24622]]

PM2.5 NAAQS for the Knoxville Area (maintenance plan), 
including the associated motor vehicle emission budgets (MVEBs) for 
nitrogen oxides (NOx) and PM2.5 for the years 2014 and 2028, 
and incorporate it into the SIP; and to redesignate the Knoxville Area 
to attainment for the 2006 24-hour PM2.5 NAAQS.

DATES: Comments must be received on or before June 29, 2017.

ADDRESSES: Submit your comments, identified by Docket ID No. EPA-R04-
OAR-2017-0086 at http://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 docket. 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 http://www2.epa.gov/dockets/commenting-epa-dockets.

FOR FURTHER INFORMATION CONTACT: Sean Lakeman of the Air Regulatory 
Management Section, in the Air Planning and Implementation Branch, Air, 
Pesticides and Toxics Management Division, U.S. Environmental 
Protection Agency, Region 4, 61 Forsyth Street, SW., Atlanta, Georgia 
30303-8960. Sean Lakeman may be reached by phone at (404) 562-9043, or 
via electronic mail at lakeman.sean@epa.gov.

SUPPLEMENTARY INFORMATION:

Table of Contents

I. What are the actions EPA is proposing to take?
II. What is the background for EPA's proposed actions?
III. What are the criteria for redesignation?
IV. Why is EPA proposing these actions?
V. What is EPA's analysis of the request?
VI. What is EPA's Analysis of the proposed NOX and 
PM2.5 MVEBs for the Knoxville area?
VII. What is the effect of EPA's proposed actions?
VIII. Proposed Actions
IX. Statutory and Executive Order Reviews

I. What are the actions EPA is proposing to take?

    EPA is proposing to take the following separate but related 
actions: (1) To approve Tennessee's RACM determination for the 
Knoxville Area pursuant to Clean Air Act (CAA or Act) sections 
172(c)(1) and 189(a)(1)(C) and incorporate it into the SIP; (2) to 
approve Tennessee's plan for maintaining the 2006 24-hour 
PM2.5 NAAQS (maintenance plan), including the associated 
MVEBs for the Knoxville Area, and incorporate it into the SIP; and (3) 
to redesignate the Knoxville Area to attainment for the 2006 24-hour 
PM2.5 NAAQS. EPA has already made its determination on the 
adequacy of the 2014 and 2028 MVEBs for the Knoxville Area for 
transportation conformity purposes and notified the public of that 
determination through publication of the Notice of Adequacy on March 
10, 2017. See 82 FR 13347. These MVEBs were effective on March 27, 
2017.\1\ The Knoxville Area consists of Anderson, Blount, Knox, and 
Loudon Counties in their entirety and a portion of Roane County (the 
area described by U.S. Census 2000 block group identifier 47-145-0307-
2). These proposed actions are summarized below and described in 
greater detail throughout this notice of proposed rulemaking.
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    \1\ EPA issued a letter to the state on February 15, 2017, 
finding the MVEBs adequate for transportation conformity purposes.
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    EPA's 2006 24-hour PM2.5 nonattainment designation for 
the Area triggered an obligation for Tennessee to develop a 
nonattainment SIP revision addressing certain CAA requirements under 
title I, part D, subpart 1 (hereinafter ``Subpart 1'') and title I, 
part D, subpart 4 (hereinafter ``Subpart 4''). Subpart 1 contains the 
general requirements for nonattainment areas for criteria pollutants, 
including requirements to develop a SIP that provides for the 
implementation of RACM (under section 172(c)(1)), requires reasonable 
further progress (RFP), includes base-year and attainment-year 
emissions inventories, and provides for the implementation of 
contingency measures. As discussed in greater detail later in this 
notice, Subpart 4 contains specific planning and scheduling 
requirements for coarse particulate matter (PM10) 
nonattainment areas, including requirements for new source review, RACM 
(under section 189(a)(1)(C)), and RFP. In the General Preamble, EPA's 
longstanding general guidance interpreting the 1990 amendments to the 
CAA, EPA discussed the relationship of Subpart 1 and Subpart 4 SIP 
requirements and pointed out that Subpart 1 requirements were to an 
extent ``subsumed by, or integrally related to, the more specific PM-10 
requirements.'' See 57 FR 13538 (April 16, 1992). Under the United 
States Court of Appeals for the District of Columbia Circuit's (D.C. 
Circuit's) January 4, 2013, decision in Natural Resources Defense 
Council v. EPA, 706 F.3d 428 (D.C. Cir. 2013), Subpart 4 requirements 
apply to PM2.5 nonattainment areas.\2\
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    \2\ In explaining its decision, the Court reasoned that the 
plain meaning of the CAA requires implementation of the 1997 
PM2.5 NAAQS under Subpart 4 because PM2.5 
particles fall within the statutory definition of PM10 
and are thus subject to the same statutory requirements. EPA 
finalized its interpretation of Subpart 4 requirements as applied to 
the PM2.5 NAAQS in its final rule entitled ``Air Quality 
State Implementation Plans; Approvals and Promulgations: Fine 
Particulate Matter National Ambient Air Quality Standards'' (81 FR 
58010, August 24, 2016).
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    On June 2, 2014, EPA published a rule entitled ``Identification of 
Nonattainment Classification and Deadlines for Submission of State 
Implementation Plan (SIP) Provisions for the 1997 Fine Particle 
(PM2.5) National Ambient Air Quality Standard (NAAQS) and 
2006 PM2.5 NAAQS'' (``Classification and Deadlines Rule''). 
See 79 FR 31566. In that rule, the Agency responded to the D.C. 
Circuit's January 2013 decision by identifying all PM2.5 
nonattainment areas for the 1997 and 2006 PM2.5 NAAQS as 
``moderate'' nonattainment areas under Subpart 4, and by establishing a 
new SIP submission date of December 31, 2014, for moderate area 
attainment plans and for any additional attainment-related or 
nonattainment new source review plans necessary for areas to comply 
with the requirements applicable under subpart 4. Id. at 31567-70.
    Based on its moderate nonattainment area classification, Tennessee 
was required to submit a SIP revision addressing RACM pursuant to CAA 
section 172(c)(1) and section 189(a)(1)(C) for the Area. Although EPA 
does not believe that section 172(c)(1) and section 189(a)(1)(C) RACM 
must be approved into a SIP prior to redesignation of an area to 
attainment once that area is attaining the NAAQS, EPA is proposing to 
approve Tennessee's RACM determination and incorporate it into its SIP 
pursuant to a recent decision by the United States Court of Appeals for 
the Sixth Circuit (Sixth Circuit) in Sierra Club v. EPA, 793 F.3d 656 
(6th Cir. 2015), as discussed in Section V.A, below.\3\
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    \3\ On August 2, 2012, EPA published a final determination that 
the Area had attained the 2006 PM2.5 NAAQS based on 
ambient air monitoring data for the 2009-2011 time period. See 77 FR 
45954. In that determination and in accordance with EPA's clean data 
policy, EPA suspended the requirements for the Area to submit a SIP 
revision addressing RACM, RFP plans, contingency measures, and 
certain other attainment planning requirements so long as the Area 
continues to attain the 2006 24-hour PM2.5 NAAQS. EPA 
notes, however, that in 2013 it issued results of a technical 
systems audit on the PM2.5 laboratory in Tennessee that 
invalidated all 2010-2012 PM2.5 monitoring data for the 
Area. After the monitoring audit issues were addressed, Tennessee 
submitted valid data for all sites, resulting in complete and valid 
design values using 2013-2015 data.

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[[Page 24623]]

    EPA also proposes to approve Tennessee's maintenance plan for the 
Knoxville Area as meeting the requirements of section 175A (such 
approval being one of the CAA criteria for redesignation to attainment 
status) and incorporate it into the SIP. The maintenance plan is 
designed to help keep the Knoxville Area in attainment for the 2006 24-
hour PM2.5 NAAQS through 2028. The maintenance plan includes 
2014 and 2028 MVEBs for NOX and direct PM2.5 for 
the Knoxville Area. EPA is proposing to approve these MVEBs and 
incorporate them into the Tennessee SIP.
    EPA also proposes to determine that the Knoxville Area has met the 
requirements for redesignation under section 107(d)(3)(E) of the CAA. 
Accordingly, in this action, EPA is proposing to approve a request to 
change the legal designation of Anderson, Blount, Knox, and Loudon 
Counties and the portion of Roane County within the Knoxville-
Sevierville-La Follette Area, as found at 40 CFR part 81, from 
nonattainment to attainment for the 2006 24-hour PM2.5 
NAAQS.
    In summary, this proposed rulemaking is in response to Tennessee's 
December 20, 2016, redesignation request and associated SIP submission 
that address the specific issues summarized above and the necessary 
elements for redesignation described in section 107(d)(3)(E) of the CAA 
for the redesignation of the Knoxville Area to attainment for the 2006 
24-hour PM2.5 NAAQS.

II. What is the background for EPA's proposed actions?

    Fine particle pollution can be emitted directly or formed 
secondarily in the atmosphere.\4\ The main precursors of secondary 
PM2.5 are sulfur dioxide (SO2), NOX, 
ammonia, and volatile organic compounds (VOCs). See, e.g., 81 FR 58010, 
58014 (August 24, 2016). Sulfates are a type of secondary particle 
formed from SO2 emissions from power plants and industrial 
facilities. Nitrates, another common type of secondary particle, are 
formed from NOX emissions from power plants, automobiles, 
and other combustion sources.
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    \4\ Fine particulate matter (PM2.5) refers to 
airborne particles less than or equal to 2.5 micrometers in 
diameter. Although treated as a single pollutant, fine particles 
come from many different sources and are composed of many different 
compounds. In the Knoxville Area, one of the sources of 
PM2.5 is fuel burning sources (such as coal-burning power 
plants, motor vehicles and combustion operations). VOCs, also 
precursors for PM, are emitted from a variety of sources, including 
motor vehicles, chemical plants, refineries, factories, consumer and 
commercial products, and other industrial sources. VOCs are also 
emitted by natural sources such as vegetation.
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    On July 18, 1997, EPA promulgated the first air quality standards 
for PM2.5. EPA promulgated an annual standard at a level of 
15.0 micrograms per cubic meter ([mu]g/m\3\), based on a 3-year average 
of annual mean PM2.5 concentrations. In the same rulemaking, 
EPA promulgated a 24-hour standard of 65 [mu]g/m\3\, based on a 3-year 
average of the 98th percentile of 24-hour concentrations. On October 
17, 2006 (71 FR 61144), EPA retained the annual average NAAQS at 15.0 
[mu]g/m\3\ but revised the 24-hour NAAQS to 35 [mu]g/m\3\, based again 
on the 3-year average of the 98th percentile of 24-hour 
concentrations.\5\ Under EPA regulations at 40 CFR part 50, the primary 
and secondary 2006 24-hour PM2.5 NAAQS are attained when the 
annual arithmetic mean concentration, as determined in accordance with 
40 CFR part 50, Appendix N, is less than or equal to 35 [micro]g/m\3\ 
at all relevant monitoring sites in the subject area averaged over a 3-
year period.
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    \5\ In response to legal challenges of the annual standard 
promulgated in 2006, the D.C. Circuit remanded that NAAQS to EPA for 
further consideration. See American Farm Bureau Federation and 
National Pork Producers Council, et al. v. EPA, 559 F.3d 512 (D.C. 
Cir. 2009). However, given that the 1997 and 2006 Annual NAAQS are 
essentially identical, attainment of the 1997 Annual NAAQS would 
also indicate attainment of the remanded 2006 Annual NAAQS.
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    On November 13, 2009, at 74 FR 58688, EPA designated the Knoxville 
Area as nonattainment for the 2006 24-hour PM2.5 NAAQS. All 
2006 PM2.5 NAAQS areas were designated under Subpart 1. 
Subpart 1 contains the general requirements for nonattainment areas for 
any pollutant governed by a NAAQS and is less prescriptive than the 
other subparts of title I, part D. On April 25, 2007 (72 FR 20586), EPA 
promulgated its Clean Air Fine Particle Implementation Rule, codified 
at 40 CFR part 51, subpart Z, in which the Agency provided guidance for 
state and tribal plans to implement the PM2.5 NAAQS. The 
D.C. Circuit remanded the Clean Air Fine Particle Implementation Rule 
and the final rule entitled ``Implementation of the New Source Review 
(NSR) Program for Particulate Matter Less than 2.5 Micrometers 
(PM2.5)'' (73 FR 28321, May 16, 2008) (collectively, ``1997 
PM2.5 Implementation Rules'') to EPA on January 4, 2013, in 
Natural Resources Defense Council v. EPA, 706 F.3d 428 (D.C. Cir. 
2013). The Court found that EPA erred in implementing the 1997 
PM2.5 NAAQS pursuant to the general implementation 
provisions of Subpart 1, rather than the particulate matter-specific 
provisions of Subpart 4.
    On July 29, 2016, EPA issued a rule entitled, ``Fine Particulate 
Matter National Ambient Air Quality Standards: State Implementation 
Plan Requirements'' (PM2.5 SIP Requirements Rule) that 
clarifies how states should meet the statutory SIP requirements that 
apply to areas designated nonattainment for any PM2.5 NAAQS 
under Subparts 1 and 4. See 81 FR 58010 (August 24, 2016). It does so 
by establishing regulatory requirements and providing guidance that is 
applicable to areas that are currently designated nonattainment for 
existing PM2.5 NAAQS and areas that are designated 
nonattainment for any PM2.5 NAAQS in the future. In 
addition, the rule responds to the D.C. Circuit's remand of the 1997 
PM2.5 Implementation Rules. As a result, the requirements of 
the rule also govern future actions associated with states' ongoing 
implementation efforts for the 1997 and 2006 PM2.5 NAAQS.

III. What are the criteria for redesignation?

    The CAA provides the requirements for redesignating a nonattainment 
area to attainment. Specifically, section 107(d)(3)(E) of the CAA 
allows for redesignation provided the following criteria are met: (1) 
The Administrator determines that the area has attained the applicable 
NAAQS; (2) the Administrator has fully approved the applicable 
implementation plan for the area under section 110(k); (3) the 
Administrator determines that the improvement in air quality is due to 
permanent and enforceable reductions in emissions resulting from 
implementation of the applicable SIP and applicable federal air 
pollutant control regulations, and other permanent and enforceable 
reductions; (4) the Administrator has fully approved a maintenance plan 
for the area as meeting the requirements of section 175A; and (5) the 
state containing such area has met all requirements applicable to the 
area under section 110 and part D of title I of the CAA.
    On April 16, 1992, EPA provided guidance on redesignation in the 
General Preamble for the Implementation of title I of the CAA 
Amendments of 1990 (57 FR 13498), and the Agency supplemented this 
guidance on April 28, 1992 (57 FR

[[Page 24624]]

18070). EPA has provided further guidance on processing redesignation 
requests in the following documents:

    1. ``Procedures for Processing Requests to Redesignate Areas to 
Attainment,'' Memorandum from John Calcagni, Director, Air Quality 
Management Division, September 4, 1992 (hereinafter referred to as 
the ``Calcagni Memorandum'');
    2. ``State Implementation Plan (SIP) Actions Submitted in 
Response to Clean Air Act (CAA) Deadlines,'' Memorandum from John 
Calcagni, Director, Air Quality Management Division, October 28, 
1992; and
    3. ``Part D New Source Review (Part D NSR) Requirements for 
Areas Requesting Redesignation to Attainment,'' Memorandum from Mary 
D. Nichols, Assistant Administrator for Air and Radiation, October 
14, 1994 (hereinafter referred to as the ``Nichols Memorandum'').

IV. Why is EPA proposing these actions?

    On December 20, 2016, Tennessee requested that EPA redesignate the 
Knoxville Area to attainment for the 2006 24-hour PM2.5 
NAAQS and submitted an associated SIP revision containing a maintenance 
plan and a RACM determination. EPA's evaluation indicates that the RACM 
determination meets the relevant requirements of the CAA and that the 
Knoxville Area meets the requirements for redesignation set forth in 
section 107(d)(3)(E), including the maintenance plan requirements under 
section 175A of the CAA. As a result of these proposed findings, EPA is 
proposing to take the three separate but related actions summarized in 
section I of this notice.

V. What is EPA's analysis of the request?

    As stated above, in accordance with the CAA, EPA proposes to: (1) 
Approve Tennessee's RACM determination for the Knoxville Area and 
incorporate it into the Tennessee SIP; (2) approve the 2006 
PM2.5 NAAQS maintenance plan, including the associated 
MVEBs, for the Knoxville Area and incorporate it into the Tennessee 
SIP; and (3) redesignate the Knoxville Area to attainment for the 2006 
24-hour PM2.5 NAAQS.

A. RACM Determination

1. Relationship Between RACM and Redesignation Criteria
    As noted above, there are a number of planning requirements in the 
CAA that are designed to help areas achieve attainment or demonstrate 
progress toward attainment. Where those areas are already attaining the 
NAAQS in question, EPA has long interpreted these requirements as not 
applicable for purposes of evaluating whether an area has a fully 
approved SIP pursuant to CAA section 107(d)(3)(E)(ii). See, e.g., 57 FR 
13498, 13564 (April 16, 1992); Calcagni Memorandum. Included in this 
category of suspended or inapplicable planning requirements are the 
provisions in Subparts 1 and 4 requiring areas to submit plans 
providing for implementation of RACM, including reasonably available 
control technology (RACT). However, in Sierra Club v. EPA, the Sixth 
Circuit vacated EPA's redesignation of the Indiana and Ohio portions of 
the Cincinnati-Hamilton nonattainment area to attainment for the 1997 
PM2.5 NAAQS because EPA had not yet approved Subpart 1 RACM 
for the Cincinnati Area into the Indiana and Ohio SIPs. The Court 
concluded that ``a State seeking redesignation `shall provide for the 
implementation' of RACM/RACT, even if those measures are not strictly 
necessary to demonstrate attainment with the PM2.5 NAAQS. . 
. . If the State has not done so, EPA cannot `fully approve' the area's 
SIP, and redesignation to attainment status is improper.'' Sierra Club, 
793 F.3d at 670.
    EPA is bound by the Sixth Circuit's decision in Sierra Club v. EPA 
within the Court's jurisdiction.\6\ Therefore, EPA is proposing to 
approve Tennessee's RACM determination into the SIP in conjunction with 
its proposal to approve the State's redesignation request for the Area 
pursuant to the Court's decision.\7\
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    \6\ The states of Kentucky, Michigan, Ohio, and Tennessee are 
located within the Sixth Circuit's jurisdiction.
    \7\ The EPA Region 4 Regional Administrator signed a memorandum 
on July 20, 2015, seeking concurrence from the Director of EPA's Air 
Quality Policy Division (AQPD) in the Office of Air Quality Planning 
and Standards to act inconsistent with EPA's interpretation of CAA 
sections 107(d)(3)(E) and 172(c)(1) when taking action on pending 
and future redesignation requests in Kentucky and Tennessee because 
the Region is bound by the Sixth Circuit's decision in Sierra Club 
v. EPA. The AQPD Director issued her concurrence on July 22, 2015. 
This memorandum is not required to satisfy EPA's regional 
consistency regulations. See 40 CFR 56.5(b)(1); 81 FR 51102 (August 
3, 2016).
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2. Proposed Approval of Tennessee's RACM Determination
    Subpart 1 requires that each attainment plan ``provide for the 
implementation of all reasonably available control measures as 
expeditiously as practicable (including such reductions in emission 
from the existing sources in the area as may be obtained through the 
adoption, at a minimum, of reasonably available control technology), 
and shall provide for attainment of the national primary ambient air 
quality standards.'' See CAA section 172(c)(1). The attainment planning 
requirements in Subpart 4 that are specific to PM10 
(including PM2.5) likewise impose upon states an obligation 
to develop attainment plans that require RACM for sources of direct 
PM2.5 and PM2.5 precursors within a moderate 
nonattainment area. CAA section 189(a)(1)(C) requires that states with 
a moderate PM2.5 nonattainment area have attainment plan 
provisions to assure that RACM is implemented by no later than four 
years after designation of the area.\8\
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    \8\ States with areas later reclassified as ``serious'' 
nonattainment areas under Subpart 4 must also develop and submit 
later plans to meet additional requirements for serious areas. See 
40 CFR 51.1003(b).
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    EPA reads CAA sections 172(c)(1) and 189(a)(1)(C), and EPA's 
implementing regulations, together to require that attainment plans for 
moderate nonattainment areas must provide for the implementation of 
RACM for existing sources of PM2.5 and PM2.5 
precursors in the nonattainment area as expeditiously as practicable 
but no later than four years after designation.\9\ As set forth in 40 
CFR 51.1009(a)(4), states are required to adopt and implement all 
technologically and economically feasible control measures for PM and 
its precursors that are necessary to bring a moderate nonattainment 
area into attainment by its attainment date or that would advance 
attainment by one year. If a state demonstrates that a control measure 
would not be necessary for attaining the standard as expeditiously as 
practicable or would not advance the attainment date, the state is not 
required to adopt such measure into its SIP. 40 CFR 51.1009(a)(4)(i)(A) 
further specifies that those measures that are identified for adoption 
and implementation constitute RACM for the area. Therefore, any measure 
that is not necessary for the area to achieve attainment or does not 
advance attainment by one year does not constitute RACM.\10\
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    \9\ This interpretation is consistent with guidance described in 
the General Preamble. See 57 FR 13498, 13540 (April 16, 1992). For 
further discussion, see 81 FR 58010, 58035 (August 24, 2016).
    \10\ Reviewing courts have upheld EPA's interpretation of RACM 
as encompassing only those measures necessary to advance attainment. 
See Sierra Club v. EPA, 314 F.3d 735, 743-745 (5th Cir. 2002); 
Sierra Club v. EPA, 294 F.3d 155, 162-163 (D.C. Cir. 2002); NRDC v. 
EPA, 571 F.3d 1245, 1252 (D.C. Cir. 2009).
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    In this action, EPA proposes to approve Tennessee's December 20, 
2016 RACM submission. In that submission, Tennessee did not identify 
any measures necessary to bring the Area into attainment, nor any 
measures that would advance attainment of the Area, because the Area is 
already attaining the 2006 24-hour PM2.5 NAAQS. Because only 
those measures that are necessary

[[Page 24625]]

to attain by the attainment date or would advance attainment by one 
year constitute RACM under CAA sections 172(c)(1), 189(a)(1), and EPA's 
implementing regulations, EPA proposes to approve Tennessee's 
determination that no additional measures are necessary to meet the 
State's obligations to have fully adopted RACM under the CAA and under 
the Sixth Circuit's decision in Sierra Club.

B. Redesignation Request and Maintenance Demonstration

    The five redesignation criteria provided under CAA section 
107(d)(3)(E) are discussed in greater detail for the Area in the 
following paragraphs of this section.
Criteria (1)--The Knoxville Area has Attained the 2006 24-hour 
PM2.5 NAAQS
    For redesignating a nonattainment area to attainment, the CAA 
requires EPA to determine that the area has attained the applicable 
NAAQS (CAA section 107(d)(3)(E)(i)). For PM2.5, an area may 
be considered to be attaining the 2006 24-hour PM2.5 NAAQS 
if it meets the standards, as determined in accordance with 40 CFR 
50.13 and Appendix N of part 50, based on three complete, consecutive 
calendar years of quality-assured air quality monitoring data. To 
attain the 2006 24-hour PM2.5 NAAQS, the 3-year average of 
the annual arithmetic mean concentration, as determined in accordance 
with 40 CFR part 50, Appendix N, must be less than or equal to 35 
[micro]g/m\3\ at all relevant monitoring sites in the subject area over 
a 3-year period. The relevant data must be collected and quality-
assured in accordance with 40 CFR part 58 and recorded in the EPA Air 
Quality System (AQS) database. The monitors generally should have 
remained at the same location for the duration of the monitoring period 
required for demonstrating attainment.
    EPA has evaluated complete, quality-assured data for the Area from 
2013-2015, and as mentioned above, has made a preliminary determination 
that the Area has attained the 2006 24-hour PM2.5 NAAQS by 
the applicable attainment date of December 31, 2015, based on this 
2013-2015 data.\11\ See 81 FR 91088 (December 16, 2016). The current 
2013-2015 PM2.5 design values are summarized in Table 1, 
below.
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    \11\ EPA has not taken final action on the December 16, 2016, 
proposal.

  Table 1--Knoxville Area 2013-2015 Design Values for the 2006 24-hour
                               PM2.5 NAAQS
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                                                             2013-2015
              Monitor site                    Site ID      design value
                                                           ([mu]g/m\3\)
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Sequoyah Ave, Maryville.................       470090011              18
Bearden Middle School...................       470930028              19
Davanna Street, Air Lab.................       470931013              19
Rule High School........................       470931017              20
Spring Hill Elementary School...........       470931020              18
Loudon Pope site........................       471050108              18
Harriman High School....................       471450004              18
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    As shown in Table 1, above, the Knoxville Area has a 2013-2015 
design value of 20 [mu]g/m\3\, which is below the 2006 24-hour 
PM2.5 NAAQS. For this proposed action, EPA has also reviewed 
2016 preliminary monitoring data for the Area and proposes to find that 
the preliminary data does not indicate a violation of the NAAQS.\12\ 
EPA will not take final action to approve the redesignation if the 3-
year design value exceeds the NAAQS prior to EPA finalizing the 
redesignation. As discussed in more detail below, Tennessee has 
committed to continue monitoring in the Knoxville Area in accordance 
with 40 CFR part 58.
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    \12\ This preliminary data is available at EPA's air data Web 
site: http://aqsdr1.epa.gov/aqsweb/aqstmp/airdata/download_files.html#Daily.
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Criteria (2)--Tennessee Has a Fully Approved SIP Under Section 110(k) 
for the Knoxville Area and Criteria (5)--Tennessee Has Met All 
Applicable Requirements Under Section 110 and Part D of the CAA
    For redesignating a nonattainment area to attainment, the CAA 
requires EPA to determine that the state has met all applicable 
requirements under section 110 and part D of title I of the CAA (CAA 
section 107(d)(3)(E)(v)) and that the state has a fully approved SIP 
under section 110(k) for the area (CAA section 107(d)(3)(E)(ii)). EPA 
proposes to find that Tennessee has met all applicable SIP requirements 
for the Knoxville Area under section 110 of the CAA (general SIP 
requirements) for purposes of redesignation. Additionally, EPA proposes 
to find that Tennessee has met all applicable SIP requirements for 
purposes of redesignation under part D of title I of the CAA in 
accordance with section 107(d)(3)(E)(v). Further, EPA proposes to 
determine that the SIP is fully approved with respect to all 
requirements applicable for purposes of redesignation in accordance 
with section 107(d)(3)(E)(ii) if EPA takes final action to incorporate 
Tennessee's RACM determination into the SIP pursuant to the Sixth 
Circuit's decision in Sierra Club v. EPA. In making these 
determinations, EPA ascertained which requirements are applicable to 
the Area and, if applicable, that they are fully approved under section 
110(k). SIPs must be fully approved only with respect to requirements 
that were applicable prior to submittal of the complete redesignation 
request.
    a. Tennessee has met all applicable requirements under section 110 
and part D of the CAA.
    General SIP requirements. General SIP elements and requirements are 
delineated in section 110(a)(2) of title I, part A of the CAA. These 
requirements include, but are not limited to, the following: submittal 
of a SIP that has been adopted by the state after reasonable public 
notice and hearing; provisions for establishment and operation of 
appropriate procedures needed to monitor ambient air quality; 
implementation of a source permit program; provisions for the 
implementation of part C requirements (Prevention of Significant 
Deterioration (PSD)) and provisions for the implementation of part D 
requirements (NNSR permit programs); provisions for air pollution 
modeling; and provisions for public and local agency participation in 
planning and emission control rule development.
    Section 110(a)(2)(D) requires that SIPs contain certain measures to 
prevent

[[Page 24626]]

sources in a state from significantly contributing to air quality 
problems in another state. To implement this provision, EPA has 
required certain states to establish programs to address the interstate 
transport of air pollutants. The section 110(a)(2)(D) requirements for 
a state are not linked with a particular nonattainment area's 
designation and classification in that state. EPA believes that the 
requirements linked with a particular nonattainment area's designation 
and classifications are the relevant measures to evaluate in reviewing 
a redesignation request. The transport SIP submittal requirements, 
where applicable, continue to apply to a state regardless of the 
designation of any one particular area in the state. Thus, EPA does not 
believe that the CAA's interstate transport requirements should be 
construed to be applicable requirements for purposes of redesignation.
    In addition, EPA believes that other section 110 elements that are 
neither connected with nonattainment plan submissions nor linked with 
an area's attainment status are not applicable requirements for 
purposes of redesignation. The area will still be subject to these 
requirements after the area is redesignated. The section 110 and part D 
requirements which are linked with a particular area's designation and 
classification are the relevant measures to evaluate in reviewing a 
redesignation request. This approach is consistent with EPA's existing 
policy on applicability (i.e., for redesignations) of conformity and 
oxygenated fuels requirements, as well as with section 184 ozone 
transport requirements. See Reading, Pennsylvania, proposed and final 
rulemakings (61 FR 53174-53176, October 10, 1996), (62 FR 24826, May 7, 
1997); Cleveland-Akron-Loraine, Ohio, final rulemaking (61 FR 20458, 
May 7, 1996); and Tampa, Florida, final rulemaking at (60 FR 62748, 
December 7, 1995). See also the discussion on this issue in the 
Cincinnati, Ohio, redesignation (65 FR 37879, June 19, 2000), and in 
the Pittsburgh, Pennsylvania, redesignation (66 FR 53094, October 19, 
2001).
    EPA has reviewed Tennessee's SIP and has preliminarily concluded 
that it meets the general SIP requirements under section 110(a)(2) of 
the CAA to the extent they are applicable for purposes of 
redesignation. EPA has previously approved provisions of Tennessee's 
SIP addressing CAA section 110(a)(2) requirements including provisions 
addressing the 2006 24-hour PM2.5 NAAQS. See 77 FR 45958 
(August 2, 2012), 78 FR 18241 (March 26, 2013), and 79 FR 26143 (May 7, 
2014). These requirements are, however, statewide requirements that are 
not linked to the PM2.5 nonattainment status of the Area. 
Therefore, EPA believes these SIP elements are not applicable for 
purposes of this redesignation.
    Title I, part D, applicable SIP requirements. EPA proposes to 
determine that Tennessee meets the applicable SIP requirements for the 
Knoxville Area for purposes of redesignation under part D of the CAA. 
Subpart 1 of part D, comprised of sections 172-179B of the CAA, sets 
forth the basic nonattainment requirements applicable to all 
nonattainment areas. For purposes of evaluating this redesignation 
request, the applicable Subpart 1 SIP requirements are contained in 
section 172(c) and in section 176. A thorough discussion of the 
requirements contained in sections 172 and 176 can be found in the 
General Preamble for Implementation of Title I. See 57 FR 13498 (April 
16, 1992). Subpart 4, found in section 189, sets forth additional 
nonattainment requirements for particulate matter nonattainment areas.
    Subpart 1, section 172 Requirements. Section 172(c) sets out 
general nonattainment plan requirements. A thorough discussion of these 
requirements can be found in the General Preamble. EPA's longstanding 
interpretation of the nonattainment planning requirements of section 
172 is that once an area is attaining the NAAQS, those requirements are 
not ``applicable'' for purposes of CAA section 107(d)(3)(E)(ii) and 
therefore need not be approved into the SIP before EPA can redesignate 
the area. In the General Preamble, EPA set forth its interpretation of 
applicable requirements for purposes of evaluating redesignation 
requests when an area is attaining a standard. See 57 FR at 13564. EPA 
noted that the requirements for RFP and other measures designed to 
provide for an area's attainment do not apply in evaluating 
redesignation requests because those nonattainment planning 
requirements ``have no meaning'' for an area that has already attained 
the standard. Id. This interpretation is also set forth in the Calcagni 
Memorandum.
    EPA's understanding of section 172 also forms the basis of its 
Clean Data Policy. Under the Clean Data Policy, EPA promulgates a 
determination of attainment, published in the Federal Register and 
subject to notice-and-comment rulemaking, and this determination 
formally suspends a state's obligation to submit most of the attainment 
planning requirements that would otherwise apply, including an 
attainment demonstration and planning SIPs to provide for RFP, RACM, 
and contingency measures under section 172(c)(9). The Clean Data Policy 
has been codified in regulations regarding the implementation of the 
ozone and PM2.5 NAAQS. See e.g., 70 FR 71612 (November 29, 
2005) and 72 FR 20586 (April 25, 2007).
    EPA's long-standing interpretation regarding the applicability of 
the section 172(c) attainment planning requirements for an area that is 
attaining a NAAQS applies in this proposed redesignation of the Area as 
well, with the exception of the applicability of the requirement to 
implement RACM under section 172(c)(1). As discussed above, the Sixth 
Circuit ruled in Sierra Club that, in order to meet the requirement of 
section 107(d)(3)(E)(ii), states are required to submit plans 
addressing RACM under section 172(c)(1) and EPA is required to approve 
those plans prior to redesignating an area, regardless of whether the 
area is attaining the standard. Because Tennessee is within the Sixth 
Circuit's jurisdiction, EPA is acting in accordance with the Sierra 
Club decision by proposing to approve Tennessee's RACM determination 
for the Area in parallel with this proposed redesignation action.
    Section 172(c)(1) requires the plans for all nonattainment areas to 
provide for the implementation of RACM as expeditiously as practicable 
and to provide for attainment of the primary NAAQS. Under this 
requirement, a state must consider all available control measures, 
including reductions that are available from adopting reasonably 
available control technology on existing sources, for a nonattainment 
area and adopt and implement such measures as are reasonably available 
in the area as components of the area's attainment demonstration. As 
discussed above, EPA is proposing to approve Tennessee's RACM 
determination and incorporate it into the SIP.
    As noted above, the remaining section 172(c) attainment planning 
requirements are not applicable for purposes of evaluating the State's 
redesignation request. Specifically, the RFP requirement under section 
172(c)(2), which is defined as progress that must be made toward 
attainment, the requirement to submit section 172(c)(9) contingency 
measures, which are measures to be taken if the area fails to make 
reasonable further progress to attainment, and the section 172(c)(6) 
requirement that the SIP contain control measures necessary to provide 
for attainment of the standard, are not applicable requirements that 
Tennessee

[[Page 24627]]

must meet here because the Area has monitored attainment of the 2006 
24-hour PM2.5 NAAQS.
    Section 172(c)(3) requires submission and approval of a 
comprehensive, accurate, and current inventory of actual emissions. On 
June 10, 2014 (79 FR 33097), EPA approved Tennessee's 2008 base-year 
emissions inventory for the Knoxville Area.
    Section 172(c)(4) requires the identification and quantification of 
allowable emissions for major new and modified stationary sources to be 
allowed in an area, and section 172(c)(5) requires source permits for 
the construction and operation of new and modified major stationary 
sources anywhere in the nonattainment area. EPA has determined that, 
since PSD requirements will apply after redesignation, areas being 
redesignated need not comply with the requirement that a NNSR program 
be approved prior to redesignation, provided that the area demonstrates 
maintenance of the NAAQS without NNSR. A more detailed rationale for 
this view is described in the Nichols Memorandum. See also rulemakings 
for the Illinois portion of the St. Louis Area (77 FR 34819, 34826, 
June 12, 2012); Louisville, Kentucky (66 FR 53665, 53669, October 23, 
2001); Grand Rapids, Michigan (61 FR 31831, 31834-31837, June 21, 
1996); Cleveland-Akron-Lorain, Ohio (61 FR 20458, 20469-20470, May 7, 
1996); Detroit, Michigan (60 FR 12459, 12467-12468, March 7, 1995). 
Tennessee has demonstrated that the Knoxville Area will be able to 
maintain the NAAQS without NNSR in effect, and therefore Tennessee need 
not have fully approved NNSR programs prior to approval of the 
redesignation request. Tennessee's PSD program will become effective in 
the Knoxville Area upon redesignation to attainment.
    Section 172(c)(7) requires the SIP to meet the applicable 
provisions of section 110(a)(2). As noted above, EPA believes that the 
Tennessee SIP meets the requirements of section 110(a)(2) applicable 
for purposes of redesignation.
    Subpart 1, section 176 Conformity Requirements. Section 176(c) of 
the CAA requires states to establish criteria and procedures to ensure 
that federally-supported or funded projects conform to the air quality 
planning goals in the applicable SIP. The requirement to determine 
conformity applies to transportation plans, programs and projects that 
are developed, funded or approved under title 23 of the United States 
Code (U.S.C.) and the Federal Transit Act (transportation conformity) 
as well as to all other federally-supported or funded projects (general 
conformity). State transportation conformity SIP revisions must be 
consistent with federal conformity regulations relating to 
consultation, enforcement and enforceability that EPA promulgated 
pursuant to its authority under the CAA.
    EPA believes that it is reasonable to interpret the conformity SIP 
requirements \13\ as not applying for purposes of evaluating the 
redesignation request under section 107(d) because state conformity 
rules are still required after redesignation and federal conformity 
rules apply where state rules have not been approved. See Wall v. EPA, 
265 F.3d 426 (6th Cir. 2001) (upholding this interpretation); 60 FR 
62748 (December 7, 1995). Nonetheless, Tennessee has an approved 
conformity SIP. See 78 FR 29027 (May 17, 2013).
---------------------------------------------------------------------------

    \13\ CAA section 176(c)(4)(E) requires states to submit 
revisions to their SIPs to reflect certain Federal criteria and 
procedures for determining transportation conformity. Transportation 
conformity SIPs are different from the MVEBs that are established in 
control strategy SIPs and maintenance plans.
---------------------------------------------------------------------------

    Subpart 4 Requirements. As discussed above, in NRDC v. EPA, the 
D.C. Circuit held that EPA should have implemented the 1997 
PM2.5 NAAQS pursuant to the particulate matter-specific 
provisions of Subpart 4. On remand, EPA identified all areas designated 
nonattainment for either the 1997 or the 2006 PM2.5 NAAQS, 
including the Knoxville Area, as moderate nonattainment areas for 
purposes of Subpart 4 in the Classification and Deadlines Rule. 
Moderate nonattainment areas are subject to the requirements of 
sections 189(a), (c), and (e), including: (1) An approved permit 
program for construction of new and modified major stationary sources 
(section 189(a)(1)(A)); (2) an attainment demonstration (section 
189(a)(1)(B)); (3) provisions for RACM (section 189(a)(1)(C)); (4) 
quantitative milestones demonstrating RFP toward attainment by the 
applicable attainment date (section 189(c)); and (5) precursor control 
(section 189(e)).\14\
---------------------------------------------------------------------------

    \14\ EPA's final implementation rule (81 FR 58010, August 24, 
2016)) includes, among other things, the Agency's interpretation of 
these moderate area requirements for purposes of PM2.5 NAAQS 
implementation.
---------------------------------------------------------------------------

    With respect to the specific attainment planning requirements under 
Subpart 4,\15\ EPA applies the same interpretation that it applies to 
attainment planning requirements under Subpart 1 or any of the other 
pollutant-specific subparts. That is, under its long-standing 
interpretation of the CAA, where an area is already attaining the 
standard, EPA does not consider those attainment planning requirements 
to be applicable for purposes of evaluating a request for 
redesignation, that is, CAA section 107(d)(3)(E)(ii) or (v), because 
requirements that are designed to help an area achieve attainment no 
longer have meaning where an area is already meeting the standard. EPA 
has proposed to determine that the Area has attained the 2006 24-hour 
PM2.5 standard. Therefore, under its longstanding 
interpretation, EPA is proposing to determine that the requirements to 
submit an attainment demonstration under section 189(a)(1)(B) and a RFP 
demonstration under section 189(c)(1) are not applicable for purposes 
of evaluating Tennessee's redesignation request. As discussed in 
greater detail above, the Sixth Circuit's decision in Sierra Club 
requires EPA to approve RACM under Subpart 1 prior to redesignation, 
and EPA is bound by the Sixth Circuit's decision within its 
jurisdiction. EPA therefore proposes to approve Tennessee's RACM 
submittal for the Knoxville Area. Such approval, if finalized, would 
also satisfy any similar obligation regarding Subpart 4 RACM.
---------------------------------------------------------------------------

    \15\ These planning requirements include the attainment 
demonstration, quantitative milestone requirements, and RACM 
analysis.
---------------------------------------------------------------------------

    The permit requirements of Subpart 4, contained in section 
189(a)(1)(A), refer to and apply the Subpart 1 permit provisions 
requirements of sections 172 and 173 to PM10, without adding 
to them. Consequently, EPA believes that section 189(a)(1)(A) does not 
itself impose for redesignation purposes any additional requirements 
for moderate areas beyond those contained in Subpart 1.\16\ As 
discussed above, EPA has long relied on the interpretation that a fully 
approved nonattainment new source review program is not considered an 
applicable requirement for redesignation, provided the area can 
maintain the standard with a PSD program after redesignation. A 
detailed rationale for this view is described in the Nichols 
Memorandum. See also rulemakings for the Illinois portion of the St. 
Louis Area (77 FR 34819, 34826, June 12, 2012); Louisville, Kentucky 
(66 FR 53665, 53669, October 23, 2001); Grand Rapids, Michigan (61 FR 
31831, 31834-31837, June 21, 1996); Cleveland-Akron-Lorain, Ohio (61 FR 
20458, 20469-20470, May 7, 1996); Detroit, Michigan (60 FR 12459, 
12467-12468, March 7, 1995).
---------------------------------------------------------------------------

    \16\ The potential effect of section 189(e) on section 
189(a)(1)(A) for purposes of evaluating this redesignation is 
discussed below.
---------------------------------------------------------------------------

    Subpart 4 and the Control of PM2.5 Precursors. CAA section 189(e) 
provides that control requirements for major

[[Page 24628]]

stationary sources of direct PM10 (including 
PM2.5) shall also apply to PM precursors from those sources, 
except where EPA determines that major stationary sources of such 
precursors ``do not contribute significantly to PM10 levels 
which exceed the standard in the area.'' The CAA does not explicitly 
address whether it would be appropriate to include a potential 
exemption from precursor controls for all source categories under 
certain circumstances. In implementing Subpart 4 with regard to 
controlling PM10, EPA permitted states to determine that a 
precursor was ``insignificant'' where the state could show in its 
attainment plan that it would expeditiously attain without adoption of 
emission reduction measures aimed at that precursor. This approach was 
upheld in Association of Irritated Residents v. EPA, 423 F.3d 989 (9th 
Cir. 2005) and extended to PM2.5 implementation in the PM 
Implementation Rule. A state may develop its attainment plan and adopt 
reasonably available control measures that target only those precursors 
that are necessary to control for purposes of timely attainment. See 81 
FR 58020. In the rule, EPA also finalized application of 189(e) to the 
NNSR permitting program, requiring states to determine whether a new 
major source of a precursor might have a significant contribution to 
air quality before allowing exemption of controls of a precursor from a 
new major stationary source or major modification in the context of 
that program. See 81 FR 58026.
    Therefore, because the requirement of section 189(e) is primarily 
actionable in the context of addressing precursors in an attainment 
plan and in NNSR permitting, a precursor exemption analysis under 
section 189(e) and EPA's implementing regulations is not an applicable 
requirement that needs be fully approved in the context of a 
redesignation under CAA section 107(d)(3)(E)(ii). As discussed above, 
for areas that are attaining the standard, EPA does not interpret 
attainment planning requirements of Subparts 1 and 4 to be applicable 
requirements for the purposes of redesignating an area to attainment 
nor does it interpret NNSR to be an applicable requirement if the area 
can maintain the NAAQS with a PSD program after redesignation. However, 
to the extent that Tennessee is required to conduct a precursor 
exemption analysis in order to satisfy 189(e) in the context of its 
RACM determination for the Knoxville Area, which is required pursuant 
to the Sixth Circuit's decision in Sierra Club, EPA proposes to find 
that the requirements of section 189(e), as interpreted by EPA's 
regulations, are met in this case. The Area has expeditiously attained 
the 2006 24-hour PM2.5 NAAQS, and therefore, no additional 
controls of any pollutant, including any PM2.5 precursor, 
are necessary to bring the Area into attainment.\17\
---------------------------------------------------------------------------

    \17\ EPA also notes that the Knoxville Area contains no major 
stationary sources of ammonia; existing major stationary sources of 
VOCs are adequately controlled under other provisions of the CAA 
regulating the ozone NAAQS; and attainment in the Area is due to 
permanent and enforceable emissions reductions on all precursors 
necessary to provide for continued attainment. The Area has reduced 
VOC emissions through the implementation of various control programs 
including VOC RACT regulations and various on-road and non-road 
motor vehicle control programs. Table 5, below, shows that future 
VOC emissions are 12 percent below the attainment year emissions 
level.
---------------------------------------------------------------------------

    For these reasons, EPA proposes to find that Tennessee has 
satisfied all applicable requirements for purposes of redesignation of 
the Knoxville Area under section 110 and part D of the CAA.
    b. Tennessee has a fully-approved applicable SIP under section 
110(k) of the CAA.
    EPA has fully approved the applicable Tennessee SIP for the 
Knoxville Area under section 110(k) of the CAA for all requirements 
applicable for purposes of redesignation with the exception of the RACM 
requirements. In today's proposed action, EPA is proposing to approve 
the RACM determination for the Area and incorporate it into the 
Kentucky SIP. EPA may rely on prior SIP approvals in approving a 
redesignation request (see Calcagni Memorandum at p. 3; Southwestern 
Pennsylvania Growth Alliance v. Browner, 144 F.3d 984 (6th Cir. 1998; 
Wall, 265 F.3d 426) plus any additional measures it may approve in 
conjunction with a redesignation action. See 68 FR 25426 (May 12, 2003) 
and citations therein. Following passage of the CAA of 1970, Tennessee 
has adopted and submitted, and EPA has fully approved at various times, 
provisions addressing the various SIP elements applicable for the 2006 
24-hour PM2.5 NAAQS in the Knoxville Area (e.g., 77 FR 
45958, August 2, 2012).
    As indicated above, EPA believes that the section 110 elements not 
connected with nonattainment plan submissions and not linked to an 
area's nonattainment status are not applicable requirements for 
purposes of redesignation. If EPA finalizes approval of the RACM 
determination, EPA has approved all part D requirements applicable 
under the 2006 24-hour PM2.5 NAAQS, as identified above, for 
purposes of this proposed redesignation pursuant to the Sixth Circuit's 
decision.
Criteria (3)--The Air Quality Improvement in the Knoxville Area Is Due 
to Permanent and Enforceable Reductions in Emissions Resulting From 
Implementation of the SIP and Applicable Federal Air Pollution Control 
Regulations and Other Permanent and Enforceable Reductions
    For redesignating a nonattainment area to attainment, the CAA 
requires EPA to determine that the air quality improvement in the area 
is due to permanent and enforceable reductions in emissions resulting 
from implementation of the SIP and applicable federal air pollution 
control regulations and other permanent and enforceable reductions (CAA 
section 107(d)(3)(E)(iii)). EPA has preliminarily determined that 
Tennessee has demonstrated that the observed air quality improvement in 
the Knoxville Area is due to permanent and enforceable reductions in 
emissions resulting from federal measures and a 2011 consent decree 
between Tennessee and the Tennessee Valley Authority (TVA).\18\
---------------------------------------------------------------------------

    \18\ Consent Decree, State of Alabama et al. v. TVA (Civil 
Action No. 3:11-cv-00170, E.D. Tenn, June 15, 2011) available in the 
docket at Appendix B to Tennessee's December 20, 2016, SIP 
submittal.
---------------------------------------------------------------------------

    Federal measures enacted in recent years have resulted in permanent 
emission reductions in particulate matter and its precursors. The 
federal measures that have been implemented include:
    Tier 2 vehicle standards and low-sulfur gasoline. On February 10, 
2000 (65 FR 6698), EPA promulgated Tier 2 motor vehicle emission 
standards and gasoline sulfur control requirements.\19\ These emission 
control requirements result in lower VOC and NOX emissions 
from new cars and light duty trucks, including sport utility vehicles. 
With respect to fuels, this rule required refiners and importers of 
gasoline to meet lower standards for sulfur in gasoline, which were 
phased in between 2004 and 2006. By 2006, refiners were required to 
meet a 30 ppm average sulfur level, with a maximum cap of 80 ppm. This 
reduction in fuel sulfur content ensures the effectiveness of low 
emission-control technologies. The Tier

[[Page 24629]]

2 tailpipe standards established in this rule were phased in for new 
vehicles between 2004 and 2009. EPA estimates that, when fully 
implemented, this rule will cut NOX and VOC emissions from 
light-duty vehicles and light-duty trucks by approximately 76 and 28 
percent, respectively. NOX and VOC reductions from medium-
duty passenger vehicles included as part of the Tier 2 vehicle program 
are estimated to be approximately 37,000 and 9,500 tons per year, 
respectively, when fully implemented. In addition, EPA estimates that 
beginning in 2007, a reduction of 30,000 tons per year of 
NOX will result from the benefits of sulfur control on 
heavy-duty gasoline vehicles. Some of these emission reductions 
occurred by the attainment years and additional emission reductions 
will occur throughout the maintenance period, as older vehicles are 
replaced with newer, compliant model years.
---------------------------------------------------------------------------

    \19\ Tennessee also identified Tier 3 Motor Vehicle Emissions 
and Fuel Standards a federal measure. EPA issued this rule on April 
28, 2014 (79 FR 23414), which applies to light duty passenger cars 
and trucks. EPA promulgated this rule to reduce air pollution from 
new passenger cars and trucks beginning in 2017. While the 
reductions did not aid the Area in attaining the standard, emissions 
reductions from these standards will occur during the maintenance 
period.
---------------------------------------------------------------------------

    Heavy-duty gasoline and diesel highway vehicle standards & ultra 
low-sulfur diesel rule. On October 6, 2000 (65 FR 59896), EPA 
promulgated a rule to reduce NOX and VOC emissions from 
heavy-duty gasoline and diesel highway vehicles that began to take 
effect in 2004. On January 18, 2001 (66 FR 5002), EPA promulgated a 
second phase of standards and testing procedures which began in 2007 to 
reduce particulate matter from heavy-duty highway engines and reduced 
the maximum highway diesel fuel sulfur content from 500 ppm to 15 ppm. 
The total program should achieve a 90 percent reduction in PM emissions 
and a 95 percent reduction in NOX emissions for new engines 
using low-sulfur diesel, compared to existing engines using higher-
content sulfur diesel. EPA expects that this rule will reduce 
NOX emissions by 2.6 million tons by 2030 when the heavy-
duty vehicle fleet is completely replaced with newer heavy-duty 
vehicles that comply with these emission standards.
    Non-road, large spark-ignition engines and recreational engines 
standards. On November 8, 2002 (67 FR 68242), EPA adopted emission 
standards for large spark-ignition engines such as those used in 
forklifts and airport ground-service equipment; recreational vehicles 
such as off-highway motorcycles, all-terrain vehicles, and snowmobiles; 
and recreational marine diesel engines. These emission standards were 
phased in from model year 2004 through 2012. When all of the non-road 
spark-ignition and recreational engine standards are fully implemented, 
an overall 72 percent reduction in hydrocarbons, 80 percent reduction 
in NOX, and 56 percent reduction in carbon monoxide 
emissions are expected by 2020. These controls help reduce ambient 
concentrations of PM2.5.
    Large non-road diesel engine standards. On June 29, 2004 (69 FR 
38958), EPA issued a rule adopting emissions standards for non-road 
diesel engines and sulfur reductions in non-road diesel fuel. This rule 
applies to diesel engines used primarily in construction, agricultural, 
and industrial applications. The rule is being phased in between 2008 
through 2015, and when fully implemented, will reduce emissions of 
NOX, VOCs, particulate matter, and carbon monoxide from 
these engines. It is estimated that compliance with this rule will cut 
NOX emissions from non-road diesel engines by up to 90 
percent nationwide.
    NOX SIP Call. On October 27, 1998 (63 FR 57356), EPA issued the 
NOX SIP Call requiring the District of Columbia and 22 
states to reduce emissions of NOX, a precursor to ozone and 
PM2.5 pollution, and providing a mechanism (the 
NOX Budget Trading Program) that states could use to achieve 
those reductions. Affected states were required to comply with Phase I 
of the SIP Call beginning in 2004 and Phase II beginning in 2007. By 
the end of 2008, ozone season NOX emissions from sources 
subject to the NOX SIP Call dropped by 62 percent from 2000 
emissions levels. All NOX SIP Call states, including 
Tennessee, have SIPs that currently satisfy their obligations under the 
NOX SIP Call, and EPA will continue to enforce the 
requirements of the NOX SIP Call.
    Reciprocating internal combustion engine National Emissions 
Standards for Hazardous Air Pollutants (NESHAP). In 2010, EPA issued 
rules regulating emissions of air toxics from existing compression 
ignition (CI) and spark ignition (SI) stationary reciprocating internal 
combustion engines (RICE) that meet specific site rating, age, and size 
criteria. With these RICE standards fully implemented in 2013, EPA 
estimates that the CI RICE standards reduce PM2.5 emissions 
from the covered CI engines by approximately 2,800 tons per year (tpy) 
and VOC emissions by approximately 27,000 tpy and that the SI RICE 
standards reduce NOX emissions from the covered SI engines 
by approximately 96,000 tpy.
    Boiler NESHAP. On March 21, 2011, EPA established emission 
standards for industrial, commercial, and institutional boilers and 
process heaters at major sources to meet hazardous air pollutant 
standards reflecting the application of maximum achievable control 
technology.\20\ See 76 FR 15608. The compliance dates for the rule are 
January 31, 2016, for existing sources and April 1, 2013, or upon 
startup, whichever is later, for new sources. New sources are defined 
as sources that began operation on or after June 4, 2010. EPA estimates 
that the rule will reduce nationwide emissions of VOC by approximately 
2,300 tpy. See 78 FR 7138 (January 31, 2013).
---------------------------------------------------------------------------

    \20\ On January 31, 2013, the EPA promulgated final amendments 
to this rule. See 78 FR 7138. Following that action, the 
Administrator received 13 petitions for reconsideration that 
identified certain issues that petitioners claimed warranted further 
opportunity for public comment. EPA took final action in response to 
these petitions on November 20, 2015. See 80 FR 72790.
---------------------------------------------------------------------------

    CAIR and CSAPR. The Clean Air Interstate Rule (CAIR) created 
regional cap-and-trade programs to reduce SO2 and 
NOX emissions in 28 eastern states, including Tennessee, 
that contributed to downwind nonattainment or interfered with 
maintenance of the 1997 8-hour ozone NAAQS and the 1997 
PM2.5 NAAQS. See 70 FR 25162 (May 12, 2005). EPA approved a 
revision to Tennessee's SIP on August 20, 2007 (72 FR 46388), that 
addressed the requirements of CAIR for the purpose of reducing 
SO2 and NOX emissions.
    In 2008, the D.C. Circuit initially vacated CAIR, North Carolina v. 
EPA, 531 F.3d 896 (D.C. Cir. 2008), but ultimately remanded the rule to 
EPA without vacatur to preserve the environmental benefits provided by 
CAIR, North Carolina v. EPA, 550 F.3d 1176, 1178 (D.C. Cir. 2008). On 
August 8, 2011 (76 FR 48208), acting on the D.C. Circuit's remand, EPA 
promulgated the Cross-State Air Pollution Rule (CSAPR) to replace CAIR 
and thus to address the interstate transport of emissions contributing 
to nonattainment and interfering with maintenance of the two air 
quality standards covered by CAIR as well as the 2006 PM2.5 
NAAQS. CSAPR requires substantial reductions of SO2 and 
NOX emissions from EGUs in 28 states in the Eastern United 
States. As a general matter, because CSAPR is CAIR's replacement, 
emissions reductions associated with CAIR will for most areas be made 
permanent and enforceable through implementation of CSAPR.
    Numerous parties filed petitions for review of CSAPR in the D.C. 
Circuit, and on August 21, 2012, the Court issued its ruling, vacating 
and remanding CSAPR to EPA and ordering continued implementation of 
CAIR. EME Homer City Generation, L.P. v. EPA, 696 F.3d 7, 38 (D.C. Cir. 
2012). The D.C. Circuit's vacatur of CSAPR was

[[Page 24630]]

reversed by the United States Supreme Court on April 29, 2014, and the 
case was remanded to the D.C. Circuit to resolve remaining issues in 
accordance with the high court's ruling. EPA v. EME Homer City 
Generation, L.P., 134 S. Ct. 1584 (2014). On remand, the D.C. Circuit 
affirmed CSAPR in most respects, but invalidated without vacating some 
of the Phase 2 SO2 and NOX ozone season CSAPR 
budgets as to a number of states. EME Homer City Generation, L.P. v. 
EPA, 795 F.3d 118 (D.C. Cir. 2015) (EME Homer City II). The 
CSAPR budgets for Tennessee are not affected by the Court's 
decision. The litigation over CSAPR ultimately delayed implementation 
of that rule for three years, from January 1, 2012, when CSAPR's cap-
and-trade programs were originally scheduled to replace the CAIR cap-
and-trade programs, to January 1, 2015. CSAPR's Phase 2 budgets were 
originally promulgated to begin on January 1, 2014, and are now 
scheduled to begin on January 1, 2017. CSAPR will continue to operate 
under the existing emissions budgets until EPA fully addresses the D.C. 
Circuit's remand.\21\ Therefore, to the extent that these transport 
rules impact attainment of the 2006 24-hour PM2.5 NAAQS in 
the Knoxville Area, any emission reductions associated with CAIR that 
helped the Knoxville Area achieve attainment of the 2006 24-hour 
PM2.5 NAAQS are permanent and enforceable for purposes of 
redesignation under section 107(d)(3)(E)(iii) of the CAA because CSAPR 
requires similar or greater emission reductions starting in 2015 and 
beyond.\22\
---------------------------------------------------------------------------

    \21\ On September 17, 2016, EPA finalized an update to the CSAPR 
ozone season program. See 81 FR 74504 (October 26, 2016). The update 
addresses summertime transport of ozone pollution in the eastern 
United States that crosses state lines to help downwind states and 
communities meet and maintain the 2008 8-hour ozone NAAQS and 
addresses the remanded Phase 2 ozone season NOX budgets. 
The update withdraws the remanded NOX budgets, sets new 
Phase 2 CSAPR ozone season NOX emissions budgets for 
eight of the eleven states with remanded budgets, and removes the 
other three states from the CSAPR ozone season NOX 
trading program. On November 10, 2016, EPA proposed to withdraw the 
federal implementation plan provisions that require affected 
electricity generating units in Texas to participate in Phase 2 of 
the CSAPR trading programs for annual emissions of SO2 
and NOX. See 81 FR 78954. Withdrawal of the FIP 
requirements is intended to address the remand of the CSAPR Phase 2 
SO2 budget for Texas. As discussed in the November 10, 
2016, notice, EPA expects that EGUs in Alabama, Georgia, and South 
Carolina will continue to participate in CSAPR trading programs for 
SO2 and annual NOX pursuant to approved SIP 
revisions (with equally or more stringent emissions budgets).
    \22\ EPA notes, however, that the Agency's air quality modeling 
analysis performed as part of the CSAPR rulemaking demonstrates that 
the Area would be able to maintain the 2006 24-hour PM2.5 
NAAQS even in the absence of either CAIR or CSAPR. See ``Air Quality 
Modeling Final Rule Technical Support Document,'' App. B-93. This 
modeling is available in the docket for this proposed redesignation 
action.
---------------------------------------------------------------------------

    In addition to the above federal measures, Tennessee identified its 
consent decree with TVA as providing emissions reductions that have 
contributed to the improvement in air quality in the region. The 
consent decree covers all of TVA's coal-fired power plants, including 
two plants located in the Area (Bull Run Fossil Plant and Kingston 
Fossil Plant), and among other things, requires system-wide annual 
tonnage limitations for SO2 (decreasing incrementally from 
285,000 tons in 2012 to 110,000 tons in 2019 and beyond); continuous 
operation of existing NOX and SO2 controls \23\ 
and PM continuous emissions monitoring systems (CEMS) at Bull Run and 
Kingston; and a maximum PM emissions rate of 0.030 pounds per million 
British Thermal Units (lb/MMBtu) of heat input at Bull Run and Kingston 
as of June 13, 2011, the consent decree obligation date.\24\ Emissions 
data from EPA's Clean Air Markets Division (CAMD) database show that 
the combined SO2 emissions from Bull Run and Kingston have 
decreased by approximately 97 percent between 2008-2014 and that 
combined NOX emissions have decreased by approximately 82 
percent during this time period.\25\
---------------------------------------------------------------------------

    \23\ Paragraphs 69 and 85 of the Consent Decree require the 
installation and continual operation of selective catalytic 
reduction (SCR) and wet flue gas recirculation (Wet FGD), 
respectively, for Bull Run Unit 1 and Kingston Units 1-9.
    \24\ Tennessee also notes that the consent decree requires the 
repowering or retirement of units at John Sevier Fossil Plant and 
Widows Creek Fossil Plant. CAMD data shows that SO2 
emissions at John Sevier, located approximately 65 miles northeast 
of Knoxville, decreased by approximately 100 percent between 2008-
2014 due to the retirement and replacement of the coal-fired units 
with natural gas combined cycle units. The retirement of Units 1 
through 6 at Widows Creek, located approximately 150 miles southwest 
of Knoxville, resulted in a 49 percent decrease in SO2 
emissions from 2008-2014 as these units were taken offline.
    \25\ See Section 3.1.1 of the State's submission for additional 
information.
---------------------------------------------------------------------------

    Tennessee incorporated the consent decree requirements most 
responsible for attaining the standard in the Area (i.e., particulate 
matter emissions limit, continuous operation of NOX and 
SO2 control equipment and PM CEMS, and compliance with the 
system-wide annual NOX and SO2 tonnage limits) 
into the Title V operating permits for Bull Run and Kingston, and the 
State submitted those permit conditions to EPA for incorporation into 
the SIP along with its request for redesignation.\26\ In a separate 
proposed action addressing the redesignation of the Knoxville Area for 
the 1997 Annual PM2.5 NAAQS, EPA has proposed to include 
these permit conditions into the SIP as source-specific requirements.
---------------------------------------------------------------------------

    \26\ See Appendix L of the State's submission for the permit 
conditions proposed for incorporation into the SIP.
---------------------------------------------------------------------------

Criteria (4)--The Knoxville Area Has a Fully Approved Maintenance Plan 
Pursuant to Section 175A of the CAA
    For redesignating a nonattainment area to attainment, the CAA 
requires EPA to determine that the area has a fully approved 
maintenance plan pursuant to section 175A of the CAA (CAA section 
107(d)(3)(E)(iv)). In conjunction with its request to redesignate the 
Knoxville Area to attainment for the 2006 24-hour PM2.5 
NAAQS, Tennessee submitted a SIP revision to provide for the 
maintenance of the 2006 24-hour PM2.5 NAAQS for at least 10 
years after the effective date of redesignation to attainment. EPA 
believes that this maintenance plan meets the requirements for approval 
under section 175A of the CAA for the reasons discussed below.
a. What is required in a maintenance plan?
    Section 175A of the CAA sets forth the elements of a maintenance 
plan for areas seeking redesignation from nonattainment to attainment. 
Under section 175A, the plan must demonstrate continued attainment of 
the applicable NAAQS for at least 10 years after the Administrator 
approves a redesignation to attainment. Eight years after the 
redesignation, Tennessee must submit a revised maintenance plan 
demonstrating that attainment will continue to be maintained for the 10 
years following the initial 10-year period. To address the possibility 
of future NAAQS violations, the maintenance plan must contain such 
contingency measures, as EPA deems necessary, to assure prompt 
correction of any future 2006 24-hour PM2.5 NAAQS 
violations. The Calcagni Memorandum provides further guidance on the 
content of a maintenance plan, explaining that a maintenance plan 
should address five requirements: The attainment emissions inventory, 
maintenance demonstration, monitoring, verification of continued 
attainment, and a contingency plan. As is discussed below, EPA proposes 
to find that Tennessee's maintenance plan includes all the necessary 
components and is thus proposing to approve it as a revision to the 
Tennessee SIP.
b. Attainment Emissions Inventory
    As discussed above, EPA has proposed to determine that the Area is

[[Page 24631]]

attaining the 2006 24-hour PM2.5 NAAQS based on monitoring 
data for the 3-year period from 2013-2015. See 81 FR 91088. In its 
maintenance plan, Tennessee selected 2014 as the attainment emission 
inventory year. The attainment inventory identifies the level of 
emissions in the Area that is sufficient to attain the 2006 24-hour 
PM2.5 NAAQS. Tennessee began development of the attainment 
inventory by first generating a baseline emissions inventory for the 
Area. As noted above, Tennessee selected 2008 as the base year for 
developing a comprehensive emissions inventory for direct 
PM2.5 and the PM2.5 precursors SO2, 
NOX, VOCs, and ammonia. The projected inventory included 
with the maintenance plan estimates emissions from 2014 to 2028, which 
satisfies the 10-year interval required in section 175(A) of the CAA.
    The emissions inventories are composed of four major types of 
sources: Point, area, on-road mobile, and non-road mobile. The 
attainment and future year emissions inventories were developed/
projected as follows:
     Point source emissions were obtained from the 2014 
National Emissions Inventory (NEI) and projected inventories were 
calculated using growth factors derived from the 2015 Annual Energy 
Outlook (AEO2015) developed by the U.S. Energy Information 
Administration. Growth factors were developed for point sources based 
on North American Industry Classification System (NAICS) codes and/or 
Source Classification Codes (SCC).
     Area source emissions were developed using EPA Nonpoint 
files located on EPA's CHIEF Emission Inventory Web site for the 2014 
NEI and projected inventories by using 2014 emissions and growth 
factors obtained from Annual Energy Outlook 2015 energy forecasts for 
consumption and production, and TranSystems Category Specific Growth 
Factors.
     On-road mobile emissions were estimated using the latest 
version of EPA's MOVES2014a model. The input parameters for the model 
runs were developed, reviewed and agreed to by the transportation 
partners through interagency consultation.\27\ Attainment year (2014) 
vehicle miles traveled (VMT) data was obtained from the Tennessee 
Department of Transportation (TDOT) through the HPMS (Highway 
Performance Monitoring System) system. Future VMT estimates were 
provided by the Knoxville Regional Transportation Planning Organization 
based on travel demand modeling performed for the nonattainment 
counties. For all interim years between the years 2014 and 2028, on-
road emissions were interpolated.
---------------------------------------------------------------------------

    \27\ The interagency consultation partners consist of the 
following entities: EPA, the United States Department of 
Transportation (Federal Highway Administration and Federal Transit 
Administration), the Knoxville Regional Transportation Planning 
Organization, Knox County Department of Air Quality Management, the 
Tennessee Department of Transportation, the Lakeway Area 
Metropolitan Transportation Planning Organization, the Great Smoky 
Mountains National Park Service, and the Tennessee Department of 
Environment and Conservation.
---------------------------------------------------------------------------

     Non-road mobile emissions were obtained from EPA's Nonroad 
files located on EPA's EIS Gateway for the 2011 NEI and using 
MOVES2014a. Future nonroad mobile emissions were projected using 2011 
emissions and national growth factors. Growth factors were multiplied 
by the 2014 emission values to calculate emissions for future years.
    The 2014 SO2, NOX, PM2.5, VOC, and 
ammonia emissions for the Knoxville Area are summarized in Tables 2 
through 6.
    Section 175A requires a state seeking redesignation to attainment 
to submit a SIP revision to provide for the maintenance of the NAAQS in 
the Area ``for at least 10 years after the redesignation.'' EPA has 
interpreted this as a showing of maintenance ``for a period of ten 
years following redesignation.'' Calcagni Memorandum, p. 9. Where the 
emissions inventory method of showing maintenance is used, the purpose 
is to show that emissions during the maintenance period will not 
increase over the attainment year inventory. Calcagni Memorandum, pp. 
9-10.
    As discussed in detail below, Tennessee's maintenance plan 
submission expressly documents that the Area's overall emissions 
inventories will remain below the attainment year inventories through 
2028. In addition, for the reasons set forth below, EPA believes that 
the Area will continue to maintain the 2006 24-hour PM2.5 
NAAQS through 2028. Thus, if EPA finalizes its proposed approval of the 
redesignation request and maintenance plan, the approval will be based 
upon this showing, in accordance with section 175A, and EPA's analysis 
described herein, that Tennessee's maintenance plan provides for 
maintenance for at least ten years after redesignation.
c. Maintenance Demonstration
    The maintenance plan for the Knoxville Area includes a maintenance 
demonstration that:
    (i) Shows compliance with and maintenance of the Annual 
PM2.5 standard by providing information to support the 
demonstration that current and future emissions of SO2, 
NOX, PM2.5, and VOCs remain at or below 2014 
emissions levels.
    (ii) Uses 2014 as the attainment year and includes future emission 
inventory projections for 2028.
    (iii) Identifies an ``out year'' at least 10 years after EPA review 
and potential approval of the maintenance plan. Per 40 CFR part 93, 
NOX and PM2.5 MVEBs were established for the last 
year (2028) of the maintenance plan. Additionally, Tennessee chose, 
through interagency consultation, to establish NOX and 
PM2.5 MVEBs for 2014 (see section VI below).
    (iv) Provides, as shown in Tables 2 through 6 below, the estimated 
and projected emissions inventories, in tons per day (tpd), for the 
Knoxville Area, for PM2.5, NOX, SO2, 
VOCs, and ammonia.

                                Table 2--Knoxville Area PM2.5 Emission Inventory
                                                      [tpd]
----------------------------------------------------------------------------------------------------------------
                                       Point           Area           Onroad          Nonroad          Total
----------------------------------------------------------------------------------------------------------------
2014............................            3.10            4.86            1.22            0.53            9.70
2017............................            2.96            4.94            1.05            0.46            9.43
2020............................            3.19            5.09            0.89            0.42            9.59
2023............................            3.25            5.24            0.73            0.40            9.61
2026............................            3.30            5.39            0.56            0.39            9.64
2028............................            3.32            5.49            0.45            0.41            9.67
----------------------------------------------------------------------------------------------------------------


[[Page 24632]]


                                 Table 3--Knoxville Area NOX Emission Inventory
                                                      [tpd]
----------------------------------------------------------------------------------------------------------------
                                       Point           Area           Onroad          Nonroad          Total
----------------------------------------------------------------------------------------------------------------
2014............................           16.55            3.09           42.73            7.64           70.01
2017............................           15.69            2.70           36.25            7.03           61.67
2020............................           16.81            2.69           29.77            6.82           56.10
2023............................           17.03            2.68           23.29            7.01           50.01
2026............................           17.27            2.67           16.81            7.65           44.40
2028............................           17.36            2.68           12.49            8.85           41.37
----------------------------------------------------------------------------------------------------------------


                                 Table 4--Knoxville Area SO2 Emission Inventory
                                                      [tpd]
----------------------------------------------------------------------------------------------------------------
                                       Point           Area           Onroad          Nonroad          Total
----------------------------------------------------------------------------------------------------------------
2014............................           11.36            0.08            0.23            0.13           11.80
2017............................            8.56            0.10            0.20            0.16            9.02
2020............................            9.37            0.10            0.17            0.21            9.86
2023............................            9.47            0.10            0.14            0.30           10.01
2026............................            9.59            0.10            0.12            0.42           10.23
2028............................            9.63            0.10            0.10            0.61           10.44
----------------------------------------------------------------------------------------------------------------


                                 Table 5--Knoxville Area VOC Emission Inventory
                                                      [tpd]
----------------------------------------------------------------------------------------------------------------
                                       Point           Area           Onroad          Nonroad          Total
----------------------------------------------------------------------------------------------------------------
2014............................            8.07           24.30           16.77            6.41           55.55
2017............................            9.46           24.35           14.58            5.48           53.88
2020............................           10.45           24.66           12.38            4.92           52.41
2023............................           11.07           24.98           10.19            4.77           51.00
2026............................           11.65           25.31            7.99            4.84           49.80
2028............................           12.00           25.51            6.53            5.11           49.14
----------------------------------------------------------------------------------------------------------------


                                 Table 6--Knoxville Area NH3 Emission Inventory
                                                      [tpd]
----------------------------------------------------------------------------------------------------------------
                                       Point           Area           Onroad          Nonroad          Total
----------------------------------------------------------------------------------------------------------------
2014............................            0.25            3.05            0.84            0.01            4.14
2017............................            0.24            3.20            0.81            0.01            4.26
2020............................            0.25            3.30            0.79            0.01            4.35
2023............................            0.25            3.38            0.76            0.01            4.41
2026............................            0.26            3.41            0.74            0.01            4.41
2028............................            0.26            3.43            0.72            0.01            4.42
----------------------------------------------------------------------------------------------------------------

    In situations where local emissions are the primary contributor to 
nonattainment, such as the Knoxville Area, if the future projected 
emissions in the nonattainment area remain at or below the baseline 
emissions in the nonattainment area, then the ambient air quality 
standard should not be exceeded in the future. As reflected above in 
Tables 2 through 5, future emissions of PM2.5, 
NOX, SO2, and VOCs in the Knoxville Area are 
expected to be below the ``attainment level'' emissions in 2014, thus 
illustrating that the Knoxville Area is expected to continue to attain 
the 2006 PM2.5 NAAQS through 2028 and beyond. Emissions of 
direct PM2.5, NOX, SO2, and VOCs in 
the Knoxville Area are expected to decrease from 2014 to 2028 by 
approximately 1 percent, 41 percent, 12 percent, and 22 percent, 
respectively. Although ammonia emissions are projected to increase 
between 2014 and 2028, the emissions increase is relatively small 
(approximately 0.28 tpd), total ammonia emissions are already 
relatively low (approximately 4.1 tpd in 2014), there are no major 
stationary sources of ammonia in the Area, the Area is well below the 
NAAQS, and the decrease in emissions of the other precursors more than 
offset the projected increase. Thus, the projected inventories indicate 
that future emissions in the Knoxville Area are expected to support 
continued maintenance of the 2006 24-hour PM2.5 NAAQS 
through 2028.
    As discussed in section VI of this proposed rulemaking, a safety 
margin is the difference between the attainment level of emissions 
(from all sources) and the projected level of emissions (from all 
sources) in the maintenance plan. The attainment level of emissions is 
the level of emissions during one of the years in which the Area met 
the NAAQS. Tennessee selected 2014 as the attainment emissions 
inventory year for the Knoxville Area. Tennessee calculated a safety 
margin in its submittal for the year 2028 and allocated the entire 
portion of the 2028 PM2.5 safety margin (in tpd) to the 2028 
MVEB for the Knoxville Area. Specifically, the entire safety margin is 
allocated to the 2028 PM2.5 MVEB. Also,

[[Page 24633]]

Tennessee allocated 7.16 tpd of the 2028 NOX safety margin 
to the 2028 NOX MVEB. The allocation and the resulting 
available safety margins for the Area are discussed further in section 
VI of this proposed rulemaking.
d. Monitoring Network
    There are currently seven monitors measuring PM2.5 in 
the Knoxville Area. Tennessee, through TDEC, has committed to continue 
operation of the monitors in the Knoxville Area in compliance with 40 
CFR part 58 and have thus addressed the requirement for monitoring. EPA 
approved Tennessee's 2016 monitoring plan on October 21, 2016.
e. Verification of Continued Attainment
    Tennessee, through TDEC, has the legal authority to enforce and 
implement the requirements of the Knoxville Area 2006 24-hour 
PM2.5 maintenance plan. This includes the authority to 
adopt, implement, and enforce any subsequent emissions control 
contingency measures determined to be necessary to correct future 
PM2.5 attainment problems.
    TDEC will track the progress of the maintenance plan by performing 
future reviews of triennial emission inventories for the Knoxville Area 
as required in the Air Emissions Reporting Rule (AERR). Emissions 
information will be compared to the 2014 attainment year to assure 
continued compliance with the 2006 24-hour PM2.5 standard.
f. Contingency Measures in the Maintenance Plan
    Section 175A of the CAA requires that a maintenance plan include 
such contingency measures as EPA deems necessary to assure that a state 
will promptly correct a violation of the NAAQS that occurs after 
redesignation. The maintenance plan should identify the contingency 
measures to be adopted, a schedule and procedure for adoption and 
implementation, and a time limit for action by Tennessee. A state 
should also identify specific indicators to be used to determine when 
the contingency measures need to be implemented. The maintenance plan 
must include a requirement that a state will implement all measures 
with respect to control of the pollutant that were contained in the SIP 
before redesignation of the area to attainment in accordance with 
section 175A(d).
    The contingency plan included in the submittal contains a 
commitment to implement measures that exist in the current SIP for 
PM2.5 and identifies triggers to determine when contingency 
measures are needed and a process of developing and implementing 
appropriate control measures. The primary trigger of the contingency 
plan is a quality assured/quality controlled violating design value of 
the 2006 24-hour PM2.5 NAAQS at any monitor. Upon activation 
of the primary trigger, Tennessee, in conjunction with the Knox County 
Department of Air Quality Management (DAQM), will commence an analysis 
to determine what additional measures will be necessary to attain or 
maintain the 2006 24-hour PM2.5 NAAQS. In the event of a 
monitored violation of the 2006 24-hour PM2.5 NAAQS in the 
Area, Tennessee commits to adopt and implement one or more of the 
following control measures within 24 months of the monitored violation 
in order to bring the Area into compliance:
     Additional RACT for point sources of PM2.5 
emissions not already covered by RACT, best available control 
technology (BACT), or reasonable and proper emission limitations;
     Additional RACM for area sources of PM2.5;
     Additional RACT for major point sources of NOX 
emissions;
     Additional RACT for minor point sources of NOX 
emissions;
     Additional RACM for area sources of NOX 
emissions;
     Additional RACT for major point sources of SO2 
emissions;
     Additional RACT for minor point sources of SO2 
emissions;
     Additional RACM for area sources of SO2 
emissions; and
     Other control measures, not included in the above list, if 
new control programs are deemed more advantageous for the Area.
    A secondary trigger is activated when one of the following 
conditions occurs that may forewarn of a potential exceedance of the 
24-hour PM2.5 NAAQS:
     A 98th-percentile PM2.5 daily value of greater 
than or equal to 37 [mu]g/m\3\ for the previous calendar year at any 
federal reference monitor (FRM) in the Area, based on quality-assured 
and certified monitoring data;
     A 98th-percentile PM2.5 daily value of greater 
than or equal to 36 [mu]g/m\3\ for each of the previous two calendar 
years at any FRM monitor in the Area, based on quality-assured and 
certified monitoring data; or
     Total emissions of PM2.5, SO2, or 
NOX in the most recent NEI for the Area exceeding 130% of 
the corresponding emissions for 2014 for that pollutant.

If the secondary trigger is activated, Tennessee and Knox County DAQM 
will investigate the occurrence and evaluate existing control measures 
to determine whether further emission reduction measures should be 
implemented.
    EPA preliminarily concludes that the maintenance plan adequately 
addresses the five basic components of a maintenance plan: attainment 
emission inventory, maintenance demonstration, monitoring network, 
verification of continued attainment, and a contingency plan. 
Therefore, EPA proposes to find that the maintenance plan SIP revision 
submitted by Tennessee for Knoxville Area meets the requirements of 
section 175A of the CAA and is approvable.

VI. What is EPA's analysis of the proposed NOX and 
PM2.5 MVEBs for the Knoxville?

    Under section 176(c) of the CAA, new transportation plans, 
programs, and projects, such as the construction of new highways, must 
``conform'' to (i.e., be consistent with) the part of a state's air 
quality plan that addresses pollution from cars and trucks. Conformity 
to the SIP means that transportation activities will not cause new air 
quality violations, worsen existing violations, or delay timely 
attainment of the NAAQS or any interim milestones. If a transportation 
plan does not conform, most new projects that would expand the capacity 
of roadways cannot go forward. Regulations at 40 CFR part 93 set forth 
EPA policy, criteria, and procedures for demonstrating and assuring 
conformity of such transportation activities to a SIP. The regional 
emissions analysis is one, but not the only, requirement for 
implementing transportation conformity. Transportation conformity is a 
requirement for nonattainment and maintenance areas. Maintenance areas 
are areas that were previously nonattainment for a particular NAAQS but 
have since been redesignated to attainment with an approved maintenance 
plan for that NAAQS.
    Under the CAA, states are required to submit, at various times, 
control strategy SIPs and maintenance plans for nonattainment areas. 
These control strategy SIPs (including RFP and attainment 
demonstration) and maintenance plans create MVEBs for criteria 
pollutants and/or their precursors to address pollution from cars and 
trucks. Per 40 CFR part 93, a MVEB must be established for the last 
year of the maintenance plan. A state may adopt MVEBs for other years 
as well. The MVEB is the portion of the total allowable emissions in 
the maintenance demonstration that is allocated to highway and transit 
vehicle

[[Page 24634]]

use and emissions. See 40 CFR 93.101. The MVEB serves as a ceiling on 
emissions from an area's planned transportation system. The MVEB 
concept is further explained in the preamble to the November 24, 1993, 
Transportation Conformity Rule (58 FR 62188). The preamble also 
describes how to establish the MVEB in the SIP and how to revise the 
MVEB.
    After interagency consultation with the transportation partners for 
the Knoxville Area, Tennessee has elected to develop MVEBs for 
NOX and PM2.5 for the entire Area. MVEBs were not 
developed for VOCs and ammonia because these pollutants are not 
significant contributors to mobile source emissions in the Knoxville 
Area. Tennessee developed these MVEBs, as required, for the last year 
of its maintenance plan, 2028. Tennessee also established MVEBs for the 
attainment year of 2014. The MVEBs reflect the total on-road emissions 
for 2014 and 2028, plus an allocation from the available NOX 
and PM2.5 safety margin. Under 40 CFR 93.101, the term 
``safety margin'' is the difference between the attainment level (from 
all sources) and the projected level of emissions (from all sources) in 
the maintenance plan. The safety margin can be allocated to the 
transportation sector; however, the total emissions must remain below 
the attainment level. The NOX and PM2.5 MVEBs and 
allocation from the safety margin were developed in consultation with 
the transportation partners and were added to account for uncertainties 
in population growth, changes in model vehicle miles traveled, and new 
emission factor models. Further details are provided below to explain 
how the NOX and PM2.5 MVEBs for 2028 were 
derived.
    The State developed a worst case scenario to estimate the potential 
emissions increases due to changes in the models and planning 
assumptions mentioned earlier. For the worst case scenario, an analysis 
year of 2045 was selected. In addition, projected VMT was increased by 
10 percent, the age of the vehicle fleet was increased by approximately 
two years, and the vehicle source type population was increased by 10 
percent above the projected vehicle source type population for 2045. 
This analysis yielded emissions of PM2.5 from on-road 
sources of about 0.22 tpd above those projected from on-road sources in 
2028. Since the entire PM2.5 safety margin of 0.03 tpd is 
allocated to the 2028 MVEB, an additional 0.19 tpd is still needed to 
cover the emissions increases modeled in the worst case scenario.
    Since there is no apparent PM2.5 safety margin remaining 
to allocate the additional 0.19 tpd to the 2028 MVEB, Tennessee 
performed a speciation data assessment to analyze the relationship 
between PM2.5 emissions and ambient concentrations and the 
impact it has on the future air quality in the Knoxville Area with the 
additional allocation to the 2028 MVEB. With the additional 0.19 tpd 
allocation, the overall PM2.5 emissions from the base year 
2014 increases from 9.70 tpd to 9.86 tpd in the out year of 2028. This 
is equal to approximately a 2 percent increase in attainment year 
PM2.5 emissions. Tennessee's analysis indicates that a 2 
percent direct PM2.5 increase will cause a 2 percent 
increase in ambient concentrations of PM2.5 which equates to 
0.43[micro]g/m\3\.
    As mentioned in Section V, the three-year design value for years 
2013-2015 is 20 [micro]g/m\3\. Therefore, the design value would be 
approximately 20.43[micro]g/m\3\ with the 2 percent increase. Even with 
the 2 percent increase in ambient PM2.5 concentrations, the 
20.43[micro]g/m\3\ design value is still below the 2006 
PM2.5 NAAQS of 35 ug/m.\28\ Furthermore, the on-road 
PM2.5 emissions as compared to the overall PM2.5 
emissions from all sectors trends downward from 12.6 percent in 2014 to 
4.7 percent in 2028. See Table 7, below.
---------------------------------------------------------------------------

    \28\ Tennessee describes the speciation analysis in Section 
4.1.5 of the submittal. See figure 4-1 for more details.

    Table 7--PM2.5 On-Road Mobile Emissions Comparison to the Total PM2.5 Emissions From All Sectors for the
                                                 Knoxville Area
                                                      [tpd]
----------------------------------------------------------------------------------------------------------------
                                        2014         2017         2020         2023         2026         2028
----------------------------------------------------------------------------------------------------------------
PM2.5 On-road emissions...........         1.22         1.05         0.89         0.73         0.56         0.45
Total PM2.5 emissions (all                 9.70         9.43         9.59         9.61         9.64         9.67
 sectors).........................
On-road % of total PM2.5 emissions         12.6         11.1          9.3          7.6          5.8          4.7
----------------------------------------------------------------------------------------------------------------

    Therefore, based on the Tennessee's speciation data assessment 
which concludes that there is a decrease in sulfate and nitrate 
concentrations even with a projected 2 percent increase in direct 
PM2.5 emissions coupled with the downward trend in on-road 
emissions, the Knoxville Area is expected to maintain the 2006 
PM2.5 standard. The NOX and 
PM2.5 MVEBs with safety margins for the Knoxville Area are 
defined in Table 8, below.

         Table 8--MVEB With Safety Margin for the Knoxville Area
                                  [tpd]
------------------------------------------------------------------------
                Pollutant                      2014            2028
------------------------------------------------------------------------
PM2.5 On-road Emissions.................            1.22            0.45
Safety Margin allocation................  ..............          * 0.22
PM2.5 MVEB..............................            1.22            0.67
NOX On-road Emissions...................           42.73           12.49
Safety Margin allocation................  ..............            7.16
NOX MVEB................................           42.73           19.65
------------------------------------------------------------------------
*The 2028 safety margin allocation includes 0.03 tons/day and an
  additional 0.19 tons/day.


[[Page 24635]]

    There is no 2028 safety margin remaining for PM2.5, and 
the remaining 2028 safety margin for NOX is 21.48 tpd. 
Through this rulemaking, EPA is proposing to approve into the Tennessee 
SIP the MVEBs for NOX and PM2.5 for 
2014 and 2028 for the Knoxville Area because EPA has determined that 
the Area maintains the 2006 24-hour PM2.5 NAAQS with the 
emissions at the levels of the budgets. The MVEBs for the Knoxville 
Area were found adequate and are currently being used to determine 
transportation conformity. After thorough review, EPA is proposing to 
approve the budgets because they are consistent with maintenance of the 
2006 24-hour PM2.5 NAAQS through 2028.

VII. What is the effect of EPA's proposed actions?

    EPA's proposed actions establish the basis upon which EPA may take 
final action on the issues being proposed for approval. Approval of 
Tennessee's redesignation request would change the legal designation of 
Anderson, Blount, Knox, and Loudon Counties and a portion of Roane 
County for the 2006 24-hour PM2.5 NAAQS, found at 40 CFR 
part 81, from nonattainment to attainment. Approval of Tennessee's 
associated SIP revision would also incorporate a plan for maintaining 
the 2006 24-hour PM2.5 NAAQS in the Area through 2028 and 
Tennessee's RACM determination into the Tennessee SIP. The maintenance 
plan includes contingency measures to remedy any future violations of 
the 2006 24-hour PM2.5 NAAQS and procedures for evaluation 
of potential violations. The maintenance plan also includes 
NOX and PM2.5 MVEBs for the Knoxville Area.

VIII. Proposed Actions

    EPA is proposing to: (1) Approve Tennessee's RACM determination for 
the Knoxville Area pursuant to CAA sections 172(c)(1) and 189(a)(1)(C) 
and incorporate it into the SIP; (2) approve Tennessee's plan for 
maintaining the 2006 24-hour PM2.5 NAAQS (maintenance plan), 
including the associated MVEBs for the Knoxville Area, and incorporate 
it into the SIP; and (3) redesignate the Knoxville Area to attainment 
for the 2006 24-hour PM2.5 NAAQS.
    If finalized, approval of the redesignation request would change 
the official designation of Anderson, Blount, Knox, and Loudon Counties 
and a portion of Roane County for the 2006 24-hour PM2.5 
NAAQS, found at 40 CFR part 81 from nonattainment to attainment, as 
found at 40 CFR part 81.

IX. Statutory and Executive Order Reviews

    Under the CAA, redesignation of an area to attainment and the 
accompanying approval of a maintenance plan under section 107(d)(3)(E) 
are actions that affect the status of a geographical area and do not 
impose any additional regulatory requirements on sources beyond those 
imposed by state law. A redesignation to attainment does not in and of 
itself create any new requirements, but rather results in the 
applicability of requirements contained in the CAA for areas that have 
been redesignated to attainment. Moreover, the Administrator is 
required to approve a SIP submission that complies with the provisions 
of the 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. 
Accordingly, these proposed actions merely approve Commonwealth 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 Order 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
     will not have disproportionate human health or 
environmental effects 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 as specified by 
Executive Order 13175 (65 FR 67249, November 9, 2000), nor will it 
impose substantial direct costs of tribal governments or preempt tribal 
law.

List of Subjects

40 CFR Part 52

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

40 CFR Part 81

    Environmental protection, Air pollution control.

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

    Dated: April 27, 2017.
V. Anne Heard,
Acting Regional Administrator, Region 4.
[FR Doc. 2017-10905 Filed 5-26-17; 8:45 am]
 BILLING CODE 6560-50-P


