```

[Federal Register Volume 80, Number 59 (Friday, March 27, 2015)]
[Proposed Rules]
[Pages 16331-16347]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2015-06963]

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Parts 52 and 81

[EPA-R04-OAR-2014-0904; FRL-9925-14-Region 4]

Approval of Implementation Plans and Designation of Areas; 
Tennessee; Redesignation of the Tennessee Portion of the Chattanooga, 
1997 PM2.5 Nonattainment Area to Attainment

AGENCY: Environmental Protection Agency.

ACTION: Proposed rule.

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SUMMARY: On November 13, 2014, the State of Tennessee, through the 
Tennessee Department of Environment and Conservation (TDEC), submitted 
a request to redesignate the Tennessee portion of the Chattanooga, TN-
GA-AL fine particulate matter (PM2.5) nonattainment area 
(hereafter referred to as the ``Chattanooga TN-GA-AL Area'' or 
``Area'') to attainment for the 1997 Annual PM2.5 national 
ambient air quality standards (NAAQS) and to approve a state 
implementation plan (SIP) revision containing a maintenance plan for 
the Tennessee portion of the Chattanooga TN-GA-AL Area. The Tennessee 
portion of the Chattanooga TN-GA-AL Area is comprised of Hamilton 
County in Tennessee. The Environmental Protection Agency (EPA) is 
proposing to approve the redesignation request and the related SIP 
revision, including TDEC's plan for maintaining attainment of the 
PM2.5 standard, for the Tennessee portion of the Chattanooga 
TN-GA-AL Area. EPA is also proposing to approve into the Tennessee SIP 
the motor vehicle emission budgets (MVEBs) for nitrogen oxides 
(NOX) and PM2.5 for the year 2025 for the 
Tennessee portion of the Chattanooga TN-GA-AL Area. In separate 
actions, EPA approved the redesignation requests and associated 
maintenance plans for the Alabama and Georgia portions of this Area.

DATES: Comments must be received on or before April 27, 2015.

ADDRESSES: Submit your comments, identified by Docket ID No. EPA-R04-
OAR-2014-0904, by one of the following methods:
    1. www.regulations.gov: Follow the on-line instructions for 
submitting comments.
    2. Email: R4-ARMS@epa.gov.
    3. Fax: (404) 562-9019.
    4. Mail: EPA-R04-OAR-2014-0904, Air Regulatory Management Section 
(formerly the Regulatory Development Section), Air Planning and 
Implementation Branch (formerly the Air Planning Branch), Air, 
Pesticides and Toxics Management Division, U.S. Environmental 
Protection Agency, Region 4, 61 Forsyth Street SW., Atlanta, Georgia 
30303-8960.
    5. Hand Delivery or Courier: Ms. Lynorae Benjamin, Chief, Air 
Regulatory Management Section, 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. Such deliveries are only accepted during the Regional 
Office's normal hours of operation. The Regional Office's official 
hours of business are Monday through Friday, 8:30 a.m. to 4:30 p.m., 
excluding Federal holidays.
    Instructions: Direct your comments to Docket ID No. EPA-R04-OAR-
2014-0904. EPA policy is that all comments received will be included in 
the public docket without change and may be made available online at 
www.regulations.gov, including any personal information provided, 
unless the comment includes information claimed to be Confidential 
Business Information (CBI) or other information whose disclosure is 
restricted by statute. Do not submit through www.regulations.gov or 
email, information that you consider to be CBI or otherwise protected. 
The www.regulations.gov Web site is an ``anonymous access'' system, 
which means EPA will not know your identity or contact information 
unless you provide it in the body of your comment. If you send an email 
comment directly to EPA without going through www.regulations.gov, your 
email address will be automatically captured and included as part of 
the comment that is placed in the public docket and made available on 
the Internet. If you submit an electronic comment, EPA recommends that 
you include your name and other contact information in the body of your 
comment and with any disk or CD-ROM you submit. If EPA cannot read your 
comment due to technical difficulties and cannot contact you for 
clarification, EPA may not be able to consider your comment. Electronic 
files should avoid the use of special characters, any form of 
encryption, and be free of any defects or viruses. For additional 
information about EPA's public docket visit the EPA Docket Center 
homepage at http://www.epa.gov/epahome/dockets.htm.
    Docket: All documents in the electronic docket are listed in the 
www.regulations.gov index. Although listed in the index, some 
information is not publicly available, i.e., CBI or other information 
whose disclosure is restricted by statute. Certain other material, such 
as copyrighted material, is not placed on the Internet and will be 
publicly available only in hard copy form. Publicly available docket 
materials are available either electronically in www.regulations.gov or 
in hard copy at the Air Regulatory Management Section, 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. EPA requests that if at all possible, you 
contact the person listed in the FOR

[[Page 16332]]

FURTHER INFORMATION CONTACT section to schedule your inspection. The 
Regional Office's official hours of business are Monday through Friday, 
8:30 a.m. to 4:30 p.m., excluding Federal holidays.

FOR FURTHER INFORMATION CONTACT: Joydeb Majumder 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. Joydeb Majumder may be reached by phone at (404) 562-9121, 
or via electronic mail at majumder.joydeb@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 the effect of January 4, 2013, D.C. Circuit decision 
regarding PM2.5 implementation under subpart 4?
VII. What is EPA's analysis of Tennessee's proposed NOX 
and PM2.5 MVEBs for the Tennessee portion of the 
Chattanooga TN-GA-AL area?
VIII. What is the status of EPA's adequacy determination for the 
proposed NOX and PM2.5 MVEBs for 2025 for the 
Tennessee portion of the Chattanooga TN-GA-AL area?
IX. Proposed Actions on the Redesignation Request and Maintenance 
Plan SIP Revisions Including Approval of the NOX and 
PM2.5 MVEBs for 2025 for the Tennessee Portion of the 
Chattanooga TN-GA-AL Area
X. What is the effect of EPA's proposed actions?
XI. Statutory and Executive Order Reviews

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

    In this action, EPA is proposing to make a determination that the 
Chattanooga TN-GA-AL Area is continuing to attain the 1997 Annual 
PM2.5 NAAQS \1\ and to take additional actions related to 
Tennessee's request to redesignate the Tennessee portion of the 
Chattanooga TN-GA-AL Area, which is summarized as follows and described 
in greater detail throughout this notice of proposed rulemaking. EPA 
proposes: (1) To redesignate the Tennessee portion of the Chattanooga 
TN-GA-AL Area to attainment for the 1997 Annual PM2.5 NAAQS; 
and (2) to approve, under section 175A of the Clean Air Act (CAA or 
Act), Tennessee's 1997 Annual PM2.5 NAAQS maintenance plan, 
including the associated MVEBs, for the Tennessee portion of the 
Chattanooga TN-GA-AL Area into the Tennessee SIP.
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    \1\ On September 8, 2011, at 76 FR 55774, EPA determined that 
the Chattanooga TN-GA-AL Area attained the 1997 PM2.5 
NAAQS by its applicable attainment date of April 5, 2010, and that 
the Area was continuing to attain the PM2.5 standard with 
monitoring data that was currently available.
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    First, EPA proposes to determine that the Tennessee portion of the 
Chattanooga TN-GA-AL Area has met the requirements for redesignation 
under section 107(d)(3)(E) of the CAA. In this action, EPA is proposing 
to approve a request to change the legal designation of Hamilton County 
in Tennessee, located within the Chattanooga TN-GA-AL Area, from 
nonattainment to attainment for the 1997 Annual PM2.5 NAAQS.
    Second, EPA is proposing to approve Tennessee's 1997 Annual 
PM2.5 NAAQS maintenance plan for the Tennessee portion of 
the Chattanooga TN-GA-AL Area (such approval being one of the CAA 
criteria for redesignation to attainment status). The maintenance plan 
is designed to help keep the Chattanooga TN-GA-AL Area in attainment 
for the 1997 Annual PM2.5 NAAQS through 2025. The 
maintenance plan that EPA is proposing to approve today includes on-
road MVEBs for direct PM2.5 and NOX for the 
Tennessee portion of the Chattanooga TN-GA-AL Area for transportation 
conformity purposes. EPA is proposing to approve the 2025 MVEBs into 
the Tennessee SIP that are included as part of Tennessee's maintenance 
plan for the 1997 Annual PM2.5 NAAQS.
    Further, EPA proposes to make the determination that the 
Chattanooga TN-GA-AL Area is continuing to attain the 1997 Annual 
PM2.5 NAAQS and that all other redesignation criteria have 
been met for the Tennessee portion of the Chattanooga TN-GA-AL Area. 
The bases for EPA's determination for the Area are discussed in greater 
detail below. EPA is also providing the public an update of the status 
of EPA's adequacy process for the 2025 MVEBs for PM2.5 and 
NOX for the Tennessee portion of the Chattanooga TN-GA-AL 
Area. Please see Section VIII of this proposed rulemaking for further 
explanation of this process and for more details.
    Today's notice of proposed rulemaking is in response to Tennessee's 
November 13, 2014, SIP revision, which requests redesignation of the 
Tennessee portion of the Chattanooga TN-GA-AL Area to attainment for 
the 1997 Annual PM2.5 NAAQS and addresses the specific 
issues summarized above and the necessary elements for redesignation 
described in section 107(d)(3)(E) of the CAA. In separate actions, EPA 
approved the redesignation requests and associated maintenance plans 
for the Alabama and Georgia portions of the Area. See 79 FR 76235 
(December 22, 2014) and 79 FR 75748 (December 19, 2014), respectively.

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

    Fine particle pollution can be emitted directly or formed 
secondarily in the atmosphere. The main precursors of secondary 
PM2.5 are sulfur dioxide (SO2), NOX, 
ammonia, and volatile organic compounds (VOC). See 72 FR 20586, 20589 
(April 25, 2007). Sulfates are a type of secondary particle formed from 
SO2 emissions of power plants and industrial facilities. 
Nitrates, another common type of secondary particle, are formed from 
NOX emissions of power plants, automobiles, and other 
combustion sources.
    On July 18, 1997, EPA promulgated the first air quality standards 
for PM2.5. EPA promulgated an annual standard at a level of 
15 micrograms per cubic meter ([mu]g/m\3\), based on a 3-year average 
of annualmean 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, EPA retained the annual average NAAQS at 15 [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.\2\ See 71 FR 
61144. Under EPA regulations at 40 CFR part 50, the primary and 
secondary 1997 Annual 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 15.0 [mu]g/m\3\ at 
all relevant monitoring sites in the subject area over a 3-year period.
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    \2\ In response to legal challenges of the annual standard 
promulgated in 2006, the United States Court of Appeals for the 
District of Columbia Circuit (D.C. Cir.) 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 January 5, 2005, and supplemented on April 14, 2005, EPA 
designated Hamilton County in Tennessee, in association with counties 
in Alabama and Georgia in the Chattanooga TN-GA-AL Area, as 
nonattainment for the 1997 PM2.5 NAAQS. See 70 FR 944 and 70 
FR 19844, respectively. On November 13, 2009, EPA promulgated 
designations for the 24-hour standard established in

[[Page 16333]]

2006, designating counties in the Chattanooga TN-GA-AL Area as 
unclassifiable/attainment for the 2006 24-hour PM2.5 NAAQS. 
See 74 FR 58688. That action also clarified that Hamilton County in the 
Chattanooga TN-GA-AL Area was classified unclassifiable/attainment for 
the 1997 24-hour PM2.5 NAAQS. EPA did not promulgate 
designations for the 2006 annual PM2.5 NAAQS because that 
NAAQS was essentially identical to the 1997 Annual PM2.5 
NAAQS. Therefore, Hamilton County in the Chattanooga TN-GA-AL Area is 
designated nonattainment for the Annual PM2.5 NAAQS 
promulgated in 1997, and today's action only addresses this 
designation.
    All 1997 PM2.5 NAAQS areas were designated under subpart 
1 of title I, part D, of the CAA. 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, EPA promulgated its PM2.5 
Implementation Rule, codified at 40 CFR part 51, subpart Z, in which 
the Agency provided guidance for state and tribal plans to implement 
the 1997 PM2.5 NAAQS. See 72 FR 20664. This rule, at 40 CFR 
51.1004(c), specifies some of the regulatory results of attaining the 
NAAQS, as discussed below. The United States Court of Appeals for the 
District of Columbia Circuit (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)'' final rule (73 FR 
28321, May 16, 2008) (collectively, ``1997 PM2.5 
Implementation Rule'') 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 of Part D of 
Title I of the CAA, rather than the particulate matter-specific 
provisions of subpart 4 of part D of title I. The effect of the court's 
ruling on this proposed redesignation action is discussed in detail in 
Section VI of this document.
    The 3-year ambient air quality data for 2007-2009 indicated no 
violations of the 1997 PM2.5 NAAQS for the Chattanooga TN-
GA-AL Area. As a result, on November 13, 2014, Tennessee requested 
redesignation of the Tennessee portion of the Chattanooga TN-GA-AL Area 
to attainment for the 1997 Annual PM2.5 NAAQS. The 
redesignation request includes three years of complete, quality-assured 
ambient air quality data for the 1997 Annual PM2.5 NAAQS for 
2007-2009, indicating that the 1997 PM2.5 NAAQS had been 
achieved for the Chattanooga TN-GA-AL Area. Under the CAA, 
nonattainment areas may be redesignated to attainment if sufficient, 
complete, quality-assured data is available for the Administrator to 
determine that the area has attained the standard and the area meets 
the other CAA redesignation requirements in section 107(d)(3)(E). The 
Chattanooga TN-GA-AL Area's design value, based on data from 2007 
through 2009, is below 15.0 [mu]g/m\3\, which demonstrates attainment 
of the standard. While Annual PM2.5 concentrations are 
dependent on a variety of conditions, the overall improvement in annual 
PM2.5 concentrations in the Tennessee portion of the 
Chattanooga TN-GA-AL Area can be attributed to the reduction of 
pollutant emissions, as discussed in more detail in Section V of this 
proposed rulemaking.
    The D.C. Circuit and the United States Supreme Court have issued a 
number of decisions and orders regarding the status of EPA's regional 
trading programs for transported air pollution, CAIR and CSAPR, that 
impact this proposed redesignation action. The effect of those court 
actions on this rulemaking is discussed in detail in Section V of this 
document.

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.
    EPA has provided guidance on redesignation in the General Preamble 
for the Implementation of title I of the CAA Amendments of 1990 (April 
16, 1992 (57 FR 13498), and supplemented on April 28, 1992 (57 FR 
18070)) and 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 (hereafter 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.

IV. Why is EPA proposing these actions?

    On November 13, 2014, TDEC requested the redesignation of the 
Tennessee portion of the Chattanooga TN-GA-AL Area to attainment for 
the 1997 Annual PM2.5 NAAQS. The Chattanooga TN-GA Area has 
attained the 1997 Annual PM2.5 NAAQS, and EPA's preliminary 
evaluation indicates that the Tennessee portion of this Area has met 
the requirements for redesignation set forth in section 107(d)(3)(E), 
including the maintenance plan requirements under section 175A of the 
CAA. EPA is also announcing the status of its adequacy determination 
for both the NOX and direct PM2.5 MVEBs for the 
Tennessee portion of the Chattanooga TN-GA-AL Area. Additionally, EPA 
is also proposing to approve the MVEBs for both NOX and 
direct PM2.5 that were included in Tennessee's maintenance 
plan.

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

    As stated above, in accordance with the CAA, EPA proposes in 
today's action to: (1) Redesignate the Tennessee portion of the 
Chattanooga TN-GA-AL Area to attainment for the 1997 Annual 
PM2.5 NAAQS; and (2) approve into the Tennessee SIP the 1997 
Annual PM2.5 NAAQS maintenance plan, including the 
associated MVEBs, for the Tennessee portion of the Chattanooga TN-GA-AL 
Area. Further, EPA proposes to make the determination that the 
Chattanooga TN-GA-AL Area continues to attain the 1997 Annual 
PM2.5 NAAQS and that all other redesignation criteria have 
been met for the Tennessee portion

[[Page 16334]]

of the Chattanooga TN-GA-AL Area. 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 Chattanooga TN-GA-AL Area Has Attained the 1997 
Annual 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)). EPA is proposing to determine that 
the Chattanooga TN-GA-AL Area continues to attain the 1997 Annual 
PM2.5 NAAQS since the May 31, 2011, attainment 
determination. See 76 FR 31239. For PM2.5, an area may be 
considered to be attaining the 1997 Annual PM2.5 NAAQS if it 
meets the 1997 Annual PM2.5 NAAQS, 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 these 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 15.0 
[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.
    On May 31, 2011, EPA determined that the Chattanooga TN-GA-AL Area 
was attaining the 1997 Annual PM2.5 NAAQS. See 76 FR 31239. 
For that action, EPA reviewed PM2.5 monitoring data from 
monitoring stations in the Chattanooga TN-GA-AL Area for the 1997 
Annual PM2.5 NAAQS for 2007-2009. These data had been 
quality-assured by the respective state agencies and are recorded in 
AQS. In addition, on September 8, 2011, at 76 FR 55774, EPA finalized a 
determination that the Chattanooga TN-GA-AL Area attained the 1997 
Annual PM2.5 NAAQS by the applicable attainment date of 
April 5, 2010. As summarized in Table 1, below, the 3-year averages of 
annual arithmetic mean concentrations (i.e., design values) for the 
years 2009 through 2013 for the Chattanooga TN-GA-AL Area are below the 
1997 Annual PM2.5 NAAQS.

                         Table 1--Design Value Concentrations for the Chattanooga TN-GA-AL Area for the 1997 Annual PM2.5 NAAQS
                                                                      [[mu]g/m\3\]
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                                                                                                               3-Year design values
                  Location                               County                Site ID  ----------------------------------------------------------------
                                                                                          2007-2009    2008-2010    2009-2011    2010-2012    2011-2013
--------------------------------------------------------------------------------------------------------------------------------------------------------
Rossville--Maple St., Georgia..............  Walker County, Georgia........   132950002       * 12.5         10.6         10.1         10.0         10.5
Siskin Drive/UTC, Tennessee................  Hamilton County, Tennessee....   470654002         12.9         11.6         11.1         10.9         10.0
Maxwell Road/East Ridge, Tennessee.........  Hamilton County, Tennessee....   470650031         12.7         11.6         11.2         11.1         10.1
Soddy-Daisy High School, Tennessee.........  Hamilton County, Tennessee....   470651011         11.1         10.7         11.0         11.2          9.8
--------------------------------------------------------------------------------------------------------------------------------------------------------
* Values subject to data substitution (76 FR 15895 (March 22, 2011)).

    As discussed above, the design value for an area is the highest 3-
year average of annual mean concentrations recorded at any monitor in 
the area. Therefore, the 3-year design value for the period on which 
Tennessee based its redesignation request (2007-2009) for the 
Chattanooga TN-GA-AL Area is 12.9 [mu]g/m\3\, which is below the 1997 
Annual PM2.5 NAAQS. Additional details can be found in EPA's 
final clean data determination for the Chattanooga TN-GA-AL Area. See 
76 FR 31239 (May 31, 2011). EPA has reviewed more recent data which 
indicate that the Chattanooga TN-GA-AL Area continues to attain the 
1997 Annual PM2.5 NAAQS beyond the submitted 3-year 
attainment period of 2007-2009. If the Area does not continue to attain 
before EPA finalizes the redesignation, EPA will not go forward with 
the redesignation. As discussed in more detail below, TDEC has 
committed to continue monitoring in this Area in accordance with 40 CFR 
part 58.

Criteria (5) --Tennessee Has Met All Applicable Requirements Under 
Section 110 and Part D of the CAA; and Criteria (2)--Tennessee Has a 
Fully Approved SIP Under Section 110(k) for the Tennessee Portion of 
the Chattanooga TN-GA-AL Area

    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 Tennessee portion of the Chattanooga TN-GA-AL Area under 
section 110 of the CAA (general SIP requirements) for purposes of 
redesignation. Additionally, EPA proposes to find that the Tennessee 
SIP satisfies the criterion that it meets applicable SIP requirements 
for purposes of redesignation under part D of title I of the CAA 
(requirements specific to 1997 Annual PM2.5 nonattainment 
areas) 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). 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. The Tennessee Portion of the Chattanooga TN-GA-AL Area Has Met All 
Applicable Requirements Under Section 110 and Part D of the CAA
    General SIP requirements. Section 110(a)(2) of title I of the CAA 
delineates the general requirements for a SIP, which include 
enforceable emissions limitations and other control measures, means, or 
techniques; provisions for the

[[Page 16335]]

establishment and operation of appropriate devices necessary to collect 
data on ambient air quality; and programs to enforce the limitations. 
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 (New Source 
Review (NSR) 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 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 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 37890, June 19, 2000), and in 
the Pittsburgh, Pennsylvania, redesignation (66 FR 50399, October 19, 
2001).
    On August 2, 2012, EPA approved all infrastructure SIP elements 
required under section 110(a)(2) for the 1997 Annual PM2.5 
NAAQS with the exception of the visibility element under section 
110(a)(2)(D)(i)(II) (also known as ``prong 4''). See 77 FR 45958. EPA 
approved prong 4 for the 1997 Annual PM2.5 NAAQS on May 7, 
2014. See 79 FR 26143. These requirements are, however, statewide 
requirements that are not linked to the PM2.5 nonattainment 
status of the Area. As stated above, EPA believes that section 110 
elements not linked to an area's nonattainment status are not 
applicable for purposes of redesignation. Therefore, EPA believes it 
has approved all SIP elements under section 110 that must be approved 
as a prerequisite for the redesignation to attainment of the Tennessee 
portion of the Chattanooga TN-GA-AL Area.
    Title I, Part D, subpart 1 applicable SIP requirements. EPA 
proposes to determine that the Tennessee SIP meets the applicable SIP 
requirements for the Tennessee portion of the Chattanooga TN-GA-AL Area 
for purposes of redesignation under part D of the CAA. Subpart 1 of 
part D, found in sections 172-176 of the CAA, sets forth the basic 
nonattainment requirements applicable to all nonattainment areas. All 
areas that were designated nonattainment for the 1997 Annual 
PM2.5 NAAQS were designated under subpart 1 of the CAA. For 
purposes of evaluating this redesignation request, the applicable part 
D, subpart 1 SIP requirements for all nonattainment areas are contained 
in sections 172(c)(1)-(9) and in section 176. A thorough discussion of 
the requirements contained in section 172 can be found in the General 
Preamble for Implementation of title I. See 57 FR 13498 (April 16, 
1992). Section VI of this proposed rulemaking notice discusses the 
relationship between this proposed redesignation action and subpart 4 
of Part D.
    Subpart 1 Section 172 Requirements. Section 172(c)(1) requires the 
plans for all nonattainment areas to provide for the implementation of 
all reasonably available control measures (RACM) as expeditiously as 
practicable and to provide for attainment of the NAAQS. EPA interprets 
this requirement to impose a duty on all nonattainment areas to 
consider all available control measures and to adopt and implement such 
measures as are reasonably available for implementation in each area as 
components of the area's attainment demonstration. Under section 172, 
states with nonattainment areas must submit plans providing for timely 
attainment and meeting a variety of other requirements.
    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 1992 General Preamble 
for Implementation of Title I, EPA set forth its interpretation of 
applicable requirements for purposes of evaluating redesignation 
requests when an area is attaining a standard. See 57 FR 13498, 13564 
(April 16, 1992). EPA noted that the requirements for reasonable 
further progress and other measures designed to provide for 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 was 
also set forth in the Calcagni Memorandum. EPA's understanding of 
section 172 also forms the basis of its Clean Data Policy, which was 
articulated with regard to PM2.5 in 40 CFR 51.1004(c), and 
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 reasonable further 
progress (RFP), RACM, and contingency measures under section 
172(c)(9).\3\ Courts have upheld EPA's interpretation of section 
172(c)(1)'s ``reasonably available'' control measures and control 
technology as meaning only those controls that advance attainment, 
which precludes the need to require additional measures where an area 
is already attaining. NRDC v. EPA, 571 F.3d 1245, 1252 (D.C. Cir. 
2009); Sierra Club v. EPA, 294 F.3d 155, 162 (D.C. Cir. 2002);

[[Page 16336]]

Sierra Club v. EPA, 314 F.3d 735, 744 (5th Cir. 2002).
---------------------------------------------------------------------------

    \3\ This regulation was promulgated as part of the 1997 
PM2.5 NAAQS implementation rule that was subsequently 
challenged and remanded in NRDC v. EPA, 706 F.3d 428 (D.C. Cir. 
2013), as discussed in Section VI of this document. However, the 
Clean Data Policy portion of the implementation rule was not at 
issue in that case.
---------------------------------------------------------------------------

    Therefore, because attainment has been reached in the Chattanooga 
TN-GA-AL Area, no additional measures are needed to provide for 
attainment, and section 172(c)(1) requirements for an attainment 
demonstration and RACM are no longer considered to be applicable for 
purposes of redesignation as long as the Area continues to attain the 
standard until redesignation. The section 172(c)(2) requirement that 
nonattainment plans contain provisions promoting reasonable further 
progress toward attainment is also not relevant for purposes of 
redesignation because EPA has determined that the Chattanooga TN-GA-AL 
Area has monitored attainment of the 1997 Annual PM2.5 
NAAQS. In addition, because the Chattanooga TN-GA-AL Area has attained 
the 1997 Annual PM2.5 NAAQS and is no longer subject to a 
RFP requirement, the requirement to submit the section 172(c)(9) 
contingency measures is not applicable for purposes of redesignation. 
Section 172(c)(6) requires the SIP to contain control measures 
necessary to provide for attainment of the NAAQS. Because attainment 
has been reached, no additional measures are needed to provide for 
attainment.
    Section 172(c)(3) requires submission and approval of a 
comprehensive, accurate, and current inventory of actual emissions. On 
February 8, 2012, EPA approved Tennessee's 2002 base-year emissions 
inventory for the Tennessee portion of the Chattanooga TN-GA-AL Area as 
part of the SIP revision submitted by TDEC to provide for attainment of 
the 1997 PM2.5 NAAQS in the Area. See 77 FR 6467.
    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 NSR program be 
approved prior to redesignation, provided that the area demonstrates 
maintenance of the NAAQS without part D NSR. A more detailed rationale 
for this view is described in a memorandum from Mary Nichols, Assistant 
Administrator for Air and Radiation, dated October 14, 1994, entitled 
``Part D New Source Review Requirements for Areas Requesting 
Redesignation to Attainment.'' Tennessee has demonstrated that the 
Tennessee portion of the Chattanooga TN-GA-AL Area will be able to 
maintain the NAAQS without part D NSR in effect, and therefore 
Tennessee need not have fully approved part D NSR programs prior to 
approval of the redesignation request. Tennessee's PSD program will 
become effective in the Tennessee portion of the Chattanooga TN-GA-AL 
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 the 
Tennessee SIP meets the requirements of section 110(a)(2) applicable 
for purposes of redesignation.
    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 \4\ 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 (upholding this interpretation) (6th Cir. 2001); See 60 FR 
62748 (December 7, 1995).
---------------------------------------------------------------------------

    \4\ 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 motor vehicle emission budgets that are 
established in control strategy SIPs and maintenance plans.
---------------------------------------------------------------------------

    Thus, for the reasons discussed above, the Tennessee portion of the 
Chattanooga TN-GA-AL Area has satisfied all applicable requirements for 
purposes of redesignation under section 110 and part D of the CAA.
b. The Tennessee Portion of the Chattanooga TN-GA-AL Area Has a Fully 
Approved Applicable SIP Under Section 110(k) of the CAA
    EPA has fully approved the applicable Tennessee SIP for the 
Tennessee portion of the Chattanooga TN-GA-AL Area for the 1997 Annual 
PM2.5 NAAQS under section 110(k) of the CAA for all 
requirements applicable for purposes of redesignation. 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 1997 Annual PM2.5 
NAAQS in the Tennessee portion of the Chattanooga TN-GA-AL 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 the 
area's nonattainment status are not applicable requirements for 
purposes of redesignation.

Criteria (3)--The Air Quality Improvement in the Chattanooga TN-GA-AL 
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 believes that Tennessee has 
demonstrated that the observed air quality improvement in the 
Chattanooga TN-GA-AL Area is due to permanent and enforceable 
reductions in emissions resulting from implementation of the SIP and 
Federal measures.
    Fine particulate matter, or 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

[[Page 16337]]

sources and are composed of many different compounds. In the 
Chattanooga TN-GA-AL Area, one of the largest components of 
PM2.5 is sulfate, which is formed through various chemical 
reactions from the precursor SO2. The other major component 
of PM2.5 is organic carbon, which originates predominantly 
from biogenic emission sources. Nitrate, which is formed from the 
precursor NOX, is also a component of PM2.5. 
Crustal materials from windblown dust and elemental carbon from 
combustion sources are less significant contributors to total 
PM2.5. 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 also are emitted by natural sources such as 
vegetation.
    Federal measures enacted in recent years have resulted in permanent 
emission reductions in particulate matter and its precursors. Most of 
these emission reductions are enforceable through regulations. The 
Federal measures that have been implemented include:
    Tier 2 vehicle standards and low-sulfur gasoline. In addition to 
requiring NOX controls, the Tier 2 rule reduced the 
allowable sulfur content of gasoline to 30 parts per million (ppm) 
starting in January of 2006. Most gasoline sold prior to this had a 
sulfur content of approximately 300 ppm.
    Heavy-duty gasoline and diesel highway vehicle standards & Ultra 
Low-Sulfur Diesel Rule. On October 6, 2000, the U.S. 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. 
See 65 FR 59896. A second phase of standards and testing procedures 
began in 2007 to reduce particulate matter from heavy-duty highway 
engines, and reduce highway diesel fuel sulfur content to 15 ppm since 
the sulfur in fuel damages high efficiency catalytic exhaust emission 
control devices. The total program should achieve a 90 percent 
reduction in PM emissions and a 95 percent reduction in NOX 
emission for new engines using low-sulfur diesel, compared to existing 
engines using higher-content sulfur diesel.
    Non-road, large spark-ignition engines and recreational engines 
standards. The non-road spark-ignition and recreational engine 
standards, effective in July 2003, regulate NOX, 
hydrocarbons, and carbon monoxide from groups of previously unregulated 
non-road engines. These engine standards apply to large spark-ignition 
engines (e.g., forklifts and airport ground service equipment), 
recreational vehicles (e.g., off-highway motorcycles and all-terrain-
vehicles), and recreational marine diesel engines sold in the United 
States and imported after the effective date of these standards.
    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 will help reduce ambient concentrations of ozone, carbon 
monoxide, and fine particulate matter.
    Large non-road diesel engine standards. Promulgated in 2004, this 
rule was phased in between 2008 and 2014. This rule will reduce sulfur 
content in non-road diesel fuel and, when fully implemented, will 
reduce NOX and direct PM2.5 emissions by over 90 
percent from these engines.
    Reciprocating Internal Combustion Engine standard. Initially 
promulgated in 2010, this rule regulates emissions of air toxics from 
existing diesel powered stationary reciprocating internal combustion 
engines that meet specific site rating, age, and size criteria. With 
all of the reciprocating internal combustion engine standards fully 
implemented in 2013, EPA estimates that PM2.5 emissions from 
these engines have been reduced by approximately 2,800 tons per year 
(tpy).
    Category 3 Marine Diesel Engine standard. Promulgated in 2010, this 
rule establishes more stringent exhaust emission standards for new 
large marine diesel engines with per cylinder displacement at or above 
30 liters (commonly referred to as Category 3 compression-ignition 
marine engines) as part of a coordinated strategy to address emissions 
from all ships that affect U.S. air quality. Near-term standards for 
newly built engines applied beginning in 2011, and long-term standards 
requiring an 80 percent reduction in NOX emissions will 
begin in 2016.
    NOX SIP Call. On October 27, 1998 (63 FR 57356), EPA 
issued a NOX SIP Call requiring the District of Columbia and 
22 states to reduce emissions of NOX. Affected states were 
required to comply with Phase I of the SIP Call beginning in 2004 and 
Phase II beginning in 2007. Emission reductions resulting from 
regulations developed in response to the NOX SIP Call are 
permanent and enforceable.
    CAIR and CSAPR. The Clean Air Interstate Rule (CAIR) was 
promulgated in 2005 and required 28 eastern states and the District of 
Columbia to significantly reduce emissions of SO2 and 
NOX from electric generating units (EGUs) in order to limit 
the interstate transport of these pollutants and the ozone and fine 
particulate matter they form in the atmosphere. See 70 FR 25162 (May 
12, 2005). 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, acting on the Court's remand, EPA promulgated 
CSAPR, to address interstate transport of emissions and resulting 
secondary air pollutants and to replace CAIR (76 FR 48208).\5\ CSAPR 
requires substantial reductions of SO2 and NOX 
emissions from EGUs in 28 states in the Eastern United States. 
Implementation of the rule was scheduled to begin on January 1, 2012, 
when CSAPR's cap-and-trade programs would have superseded the CAIR cap-
and-trade programs. Numerous parties filed petitions for review of 
CSAPR, and on December 30, 2011, the D.C. Circuit issued an order 
staying CSAPR pending resolution of the petitions and directing EPA to 
continue to administer CAIR. EME Homer City Generation, L.P. v. EPA, 
No. 11-1302 (D.C. Cir. Dec. 30, 2011), Order at 2.
---------------------------------------------------------------------------

    \5\ CAIR addressed the 1997 PM2.5 Annual standard and 
the 1997 8-hour ozone standard. CSAPR addresses contributions from 
upwind states to downwind nonattainment and maintenance of the 2006 
24-hour PM2.5 standard as well as the ozone and 
PM2.5 NAAQS addressed by CAIR.
---------------------------------------------------------------------------

    On August 21, 2012, the D.C. Circuit issued its ruling, vacating 
and remanding CSAPR to the Agency and once again 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 subsequently denied EPA's 
petition for rehearing en banc. EME Homer City Generation, L.P. v. EPA, 
No. 11-1302, 2013 WL 656247 (D.C. Cir. Jan. 24, 2013), at *1. EPA and 
other parties then petitioned the Supreme Court for a writ of 
certiorari, and the Supreme Court granted the petitions on June 24, 
2013. EPA v. EME Homer City Generation, L.P., 133 S. Ct. 2857 (2013).
    On April 29, 2014, the Supreme Court vacated and reversed the D.C. 
Circuit's decision regarding CSAPR and remanded that decision to the 
D.C. Circuit to resolve remaining issues in accordance with its ruling. 
EPA v. EME Homer City Generation, L.P., 134 S. Ct. 1584 (2014). EPA 
filed a motion to lift the stay in light of the Supreme Court decision, 
and on October 23, 2014, the

[[Page 16338]]

D.C. Circuit granted EPA's motion. EME Homer City Generation, L.P. v. 
EPA, Case No. 11-1302, Document No. 1518738. EPA subsequently issued an 
interim final rule amending the Code of Federal Regulations to 
correctly reflect the compliance deadlines for CSAPR as revised by the 
effect of the Court's order granting EPA's motion to lift the stay of 
CSAPR and delay its deadlines by three years. See 79 FR 71663 (December 
3, 2014). These amendments make clear that, consistent with the Court's 
order, compliance with CSAPR's Phase 1 emissions budgets is now 
required in 2015 and 2016 (instead of 2012 and 2013) and compliance 
with the rule's Phase 2 emissions budgets and assurance provisions is 
now required in 2017 and beyond (instead of 2014 and beyond).
    EPA approved a modification to Tennessee's SIP on November 25, 
2009, that addressed the requirements of CAIR for the purpose of 
reducing SO2 and NOX emissions (see 74 FR 61535), 
and Tennessee's SIP redesignation request lists CAIR/CSAPR as a control 
measure. CAIR was in place and getting emission reductions when the 
Chattanooga TN-GA-AL Area began monitoring attainment of the 1997 
Annual PM2.5 NAAQS. The quality-assured, certified 
monitoring data used to demonstrate the area's attainment of the 1997 
Annual PM2.5 NAAQS by the April 5, 2010, attainment deadline 
was also impacted by CAIR. However, EPA conducted an air quality 
modeling analysis as part of the CSAPR rulemaking which demonstrates 
that the Chattanooga TN-GA-AL Area would be able to maintain the 1997 
Annual PM2.5 NAAQS even in the absence of either CAIR or 
CSAPR. See ``Air Quality Modeling Final Rule Technical Support 
Document,'' App. B-40 and B-59.\6\ This modeling is available in the 
docket for this proposed redesignation action. In addition, as noted 
above, the D.C. Circuit has lifted the stay of CSAPR and EPA has made 
ministerial amendments to CSAPR consistent with the Court's order. 
Therefore, to the extent that these transport rules impact attainment 
of the 1997 Annual PM2.5 NAAQS in the Chattanooga TN-GA-AL 
Area, any emission reductions associated with CAIR that helped the 
Chattanooga TN-GA-AL Area achieve attainment of the 1997 Annual 
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 from relevant upwind 
areas starting in 2015 and beyond.
---------------------------------------------------------------------------

    \6\ The air quality modeling analysis for the CSAPR rulemaking 
did not identify any of the four monitors in the Chattanooga TN-GA-
AL Area as receptors.
---------------------------------------------------------------------------

Criteria (4)--The Tennessee Portion of the Chattanooga TN-GA-AL 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 
Tennessee portion of the Chattanooga TN-GA-AL Area to attainment for 
the 1997 Annual PM2.5 NAAQS, TDEC submitted a SIP revision 
to provide for the maintenance of the 1997 Annual 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.
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, TDEC must submit a revised maintenance plan which 
demonstrates 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 1997 Annual PM2.5 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 
TDEC's maintenance plan includes all the necessary components and is 
thus proposing to approve it as a revision to the Tennessee SIP.
b. CAA 175 Maintenance Plan Requirements
1. Attainment Emissions Inventory
    The Chattanooga TN-GA-AL Area attained the 1997 Annual 
PM2.5 NAAQS based on monitoring data for the 3-year period 
from 2007-2009. TDEC has selected 2007 as the attainment emission 
inventory year. The attainment inventory identifies a level of 
emissions in the Area that is sufficient to attain the 1997 Annual 
PM2.5 NAAQS. TDEC began development of the attainment 
inventory by first generating a baseline emissions inventory for the 
Tennessee portion of the Chattanooga TN-GA-AL Area. As noted above, the 
year 2007 was chosen as the base year for developing a comprehensive 
emissions inventory for direct PM2.5 and PM2.5 
precursors SO2 and NOX. Emissions projections to 
support maintenance through 2025 have been prepared for the years 2010, 
2013, 2016, 2019, 2022, and 2025. The projected inventory included with 
the maintenance plan estimates emissions forward to 2025, 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 
projected annual emissions from point and area sources were determined 
by applying Economic Growth Analysis System version 5.0 for Hamilton 
County to respective attainment year emissions. The projected annual 
emissions from onroad mobile sources within Hamilton County for 2025 
were determined by using the MOVES2010b model. Projected annual 
emissions from nonroad mobile sources within Hamilton County were 
determined by using the NONROAD2008a model. The 2007 SO2, 
NOX, and PM2.5 emissions for the Tennessee 
portion of the Chattanooga TN-GA-AL Area, as well as the emissions for 
other years, were developed consistent with EPA guidance and are 
summarized in Tables 2 through 6 of the following subsection discussing 
the maintenance demonstration.
2. Maintenance Demonstration
    The November 13, 2014, final submittal includes a maintenance plan 
for the Tennessee portion of the Chattanooga TN-GA-AL Area. This 
demonstration:
    (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, and

[[Page 16339]]

PM2.5 will remain below 2007 emission levels.
    (ii) Uses 2007 as the attainment year and includes future emission 
inventory projections for 2010, 2013, 2016, 2019, 2022, and 2025.
    (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 (2025) of the maintenance plan.
    (iv) Provides, as shown in Tables 2, 3, 4, 5, and 6 below, the 
actual and projected emissions inventories, in tpy, for the Tennessee 
portion of the Chattanooga TN-GA-AL Area.

                 Table 2--Actual (2007) and Projected Point Source Emissions for the Tennessee Portion of the Chattanooga TN-GA-AL Area
                                                                         [tons]
--------------------------------------------------------------------------------------------------------------------------------------------------------
                          Pollutant                                2007         2010         2013         2016         2019         2022         2025
--------------------------------------------------------------------------------------------------------------------------------------------------------
SO2..........................................................        919.2        797.5        808.1        798.0        819.4        842.1        865.6
NOX..........................................................      2,437.2      2,484.1      2,575.6      2,650.6      2,811.6      2,982.2      3,154.6
PM2.5........................................................        160.2        156.3        158.2        169.2        180.7        193.1        205.8
--------------------------------------------------------------------------------------------------------------------------------------------------------

               Table 3--Actual (2007) and Projected Non-Point Source Emissions for the Tennessee Portion of the Chattanooga TN-GA-AL Area
                                                                         [tons]
--------------------------------------------------------------------------------------------------------------------------------------------------------
                          Pollutant                                2007         2010         2013         2016         2019         2022         2025
--------------------------------------------------------------------------------------------------------------------------------------------------------
SO2..........................................................        332.6        346.7        363.2        382.9        401.1        420.6        441.1
NOX..........................................................      3,415.1      3,638.0      3,835.2      4,089.8      4,348.5      4,609.0      4,880.6
PM2.5........................................................        875.4        916.6        955.8      1,001.2      1,042.6      1,083.6      1,121.9
--------------------------------------------------------------------------------------------------------------------------------------------------------

            Table 4--Actual (2007) and Projected On-Road Mobile Sources Emissions for the Tennessee Portion of the Chattanooga TN-GA-AL Area
                                                                         [tons]
--------------------------------------------------------------------------------------------------------------------------------------------------------
                          Pollutant                                2007         2010         2013         2016         2019         2022         2025
--------------------------------------------------------------------------------------------------------------------------------------------------------
SO2..........................................................         87.6         77.1         66.5         56.0         45.5         34.9         24.4
NOX..........................................................     11,465.2      9,972.4      8,479.7      6,986.9      5,494.2      4,001.5      2,508.7
PM2.5........................................................        395.1        342.0        288.9        235.8        182.7        129.6         79.5
--------------------------------------------------------------------------------------------------------------------------------------------------------

            Table 5--Actual (2007) and Projected Non-Road Mobile Source Emissions for the Tennessee Portion of the Chattanooga TN-GA-AL Area
                                                                         [tons]
--------------------------------------------------------------------------------------------------------------------------------------------------------
                          Pollutant                                2007         2010         2013         2016         2019         2022         2025
--------------------------------------------------------------------------------------------------------------------------------------------------------
SO2..........................................................         99.3         25.9         15.2         14.2         14.7         15.3         15.9
NOX..........................................................      1,792.1      1,562.6      1,264.3      1,003.4        833.6        730.8        675.2
PM2.5........................................................        153.6        141.6        123.7        101.0         82.4         70.4         63.5
--------------------------------------------------------------------------------------------------------------------------------------------------------

                Table 6--Actual (2007) and Projected Emissions for All Sectors for the Tennessee Portion of the Chattanooga TN-GA-AL Area
                                                                         [tons]
--------------------------------------------------------------------------------------------------------------------------------------------------------
                          Pollutant                                2007         2010         2013         2016         2019         2022         2025
--------------------------------------------------------------------------------------------------------------------------------------------------------
SO2..........................................................      1,438.8      1,247.2      1,253.2      1,251.1      1,280.7      1,312.9      1,346.9
NOX..........................................................     19,109.5     17,657.2     16,154.7     14,730.8     13,487.9     12,323.4     11,219.1
PM2.5........................................................      1,584.3      1,556.5      1,526.6      1,507.3      1,488.4      1,476.7      1,467.8
--------------------------------------------------------------------------------------------------------------------------------------------------------

    Table 2 shows a slight increase of NOX, and 
PM2.5 from point sources, and Table 3 indicates a slight 
increase of NOX, SO2, and PM2.5 from 
nonpoint emission sources. Table 6 reflects the overall emissions from 
all source categories in the Tennessee portion of the Chattanooga, TN-
GA-AL. Overall emissions from all source categories combined for all 
three pollutants, NOX, SO2, and PM2.5, 
are projected to decrease from 2007 to 2025. In situations where local 
emissions are the primary contributor to nonattainment, such as the 
Chattanooga TN-GA-AL 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 explained below, EPA proposes to find that 
the overall emission projections illustrate that the Chattanooga TN-GA-
AL Area is expected to continue to attain the 1997

[[Page 16340]]

Annual PM2.5 NAAQS through 2025.\7\ Emissions of 
SO2, NOX, and PM2.5 are projected to 
decline by 6.4 percent, 41.3 percent and 7.4 percent, respectively, 
from 2007 to 2025.
---------------------------------------------------------------------------

    \7\ In separate actions, EPA approved the redesignation requests 
and associated maintenance plans for the Alabama and Georgia 
portions of the Area. See 79 FR 76235 (December 22, 2014) and 79 FR 
75748 (December 19, 2014), respectively. Therefore, EPA does not 
believe that projected emissions from those portions of the Area 
present a maintenance problem for air quality in the Area as a 
whole.
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    A maintenance plan requires the state to show that projected future 
year overall emissions will not exceed the level of emissions which led 
the Area to attain the NAAQS. For the reasons discussed above, EPA 
preliminarily agrees that Tennessee's projected emissions demonstrate 
that the Chattanooga TN-GA-AL Area will continue to attain for the 
duration of the maintenance plan.
3. Monitoring Network
    There are currently three monitors measuring ambient 
PM2.5 in the Chattanooga TN-GA-AL Area. TDEC has committed 
to continue operation of the monitors in the Tennessee portion of 
Chattanooga TN-GA-AL Area in compliance with 40 CFR part 58 and have 
thus addressed the requirement for monitoring. EPA approved Tennessee's 
2013 monitoring plan on November 14, 2013. In addition, there is 
currently one monitor measuring ambient PM2.5 in the Georgia 
portion of the Chattanooga TN-GA-AL Area. Georgia Environmental 
Protection Division (GA EPD) has committed to continue operation of the 
monitor in the Georgia portion of the Chattanooga TN-GA-AL Area in 
compliance with 40 CFR part 58 and has thus addressed the requirement 
for monitoring. On December 19, 2014, EPA approved GA EPD's submittal 
to redesignate the Georgia portion of Chattanooga TN-GA-AL Area from 
nonattainment to attainment for the 1997 Annual PM2.5 NAAQS. 
See 79 FR 75748. There is no monitor in the Alabama portion of the 
Chattanooga TN-GA-AL Area.
4. Verification of Continued Attainment
    TDEC has the legal authority to enforce and implement the 
requirements of the Tennessee portion of the Chattanooga TN-GA-AL Area 
1997 Annual 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 Tennessee 
portion of the Chattanooga TN-GA-AL Area as required in the Air 
Emissions Reporting Rule (AERR) and Consolidated Emissions Reporting 
Rule (CERR). For these periodic inventories, TDEC will review the 
assumptions made for the purpose of the maintenance demonstration 
concerning projected growth of activity levels. If any of these 
assumptions appear to have changed substantially, then TDEC will re-
project emissions for the Tennessee portion of the Chattanooga TN-GA-AL 
Area.
5. 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 the 
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 the state. 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). TDEC has identified the following possible means for 
providing further reductions in emissions of PM2.5 and/or 
its significant precursors as contingency measures for emission sources 
within Hamilton County:
     Reasonably available control technology (RACT) for point 
sources of PM2.5 emissions not already covered by RACT, best 
available control technology, or reasonable and proper emission 
limitations;
     RACM for area sources of PM2.5 emissions;
     RACT for major point-sources of NOX emissions;
     RACT for minor point-sources of NOX emissions;
     RACM for area sources of NOX emissions;
     RACT for major point-sources of SO2 emissions;
     RACT for minor point-sources of SO2 emissions;
     RACM for area sources of SO2 emissions; and
     Additional PM2.5, NOX, and/or 
SO2 emissions reduction measures yet to be identified.
    The contingency plan included in the submittal includes a 
triggering mechanism to determine when contingency measures are needed 
and a process of developing and implementing appropriate control 
measures. TDEC will use actual ambient monitoring data to determine 
whether a trigger event has occurred and when contingency measures 
should be implemented.
    An exceedance of the 1997 Annual PM2.5 NAAQS of 15.0 
[micro]g/m\3\ at any federal reference method (FRM) monitor in the 
Chattanooga TN-GA-AL maintenance area, based on quality-assured and 
certified monitoring data averaged over three consecutive calendar 
years, will trigger a comprehensive evaluation by TDEC to determine if 
contingency measures should be implemented. Furthermore, such an 
evaluation will also be triggered by the occurrence of any of the 
following conditions that may forewarn of a potential exceedance of the 
annual PM2.5 NAAQS.
     An annual mean PM2.5 concentration (average of 
quarterly-average concentrations) of greater than or equal to 16.5 
[micro]g/m\3\ for the previous calendar year at any FRM monitor in the 
Chattanooga TN-GA-AL maintenance area, based on quality-assured and 
certified monitoring data;
     An annual mean PM2.5 (average of quarterly-
average concentrations) of greater than or equal to 15.5 [micro]g/m\3\ 
for each of the previous two consecutive calendar years at any FRM 
monitor in the Chattanooga TN-GA-AL maintenance area, based on the 
quality-assured and certified monitoring data;
     Total emissions of PM2.5 in the most recent NEI 
for Hamilton County of greater than 2,059 tons, which is thirty percent 
more than the corresponding emissions for 2007, the attainment year; 
and
     Total emissions of SO2 in the most recent NEI 
for Hamilton County of greater than 1,870 tons, which is thirty percent 
more than the corresponding emissions for 2007.
    Upon occurrence of a contingency measure trigger, the required 
comprehensive evaluation will be conducted to determine the cause(s) of 
the elevated ambient PM2.5 concentrations or emissions 
inventory increase, to determine if an exceedance of the annual 
PM2.5 NAAQS is likely to occur or continue, and to determine 
whether or not the adoption and implementation of appropriate 
contingency measures is required for the further reduction of emissions 
of PM2.5 and/or its significant precursors within

[[Page 16341]]

Hamilton County. The evaluation will examine:
     Severity of the trigger condition;
     Potentially contributing emissions from sources within 
Hamilton County;
     Potentially contributing emissions resulting from regional 
or long-range transport;
     Potentially contributing meteorological conditions, if 
applicable;
     Emission trends for all source types;
     Future emissions reductions from any adopted or planned 
regulations or initiatives;
     Current and recently identified emissions control 
technologies applicable to considered contingency measures;
     Emissions reduction potential of considered contingency 
measures;
     Technical and economic feasibility of considered 
contingency measures;
     Possible geographic limitations of considered contingency 
measures; and
     Implementation timeline of considered contingency 
measures.
    EPA has concluded that the maintenance plan adequately addresses 
the five basic components required: The attainment emissions inventory, 
maintenance demonstration, monitoring, verification of continued 
attainment, and a contingency plan. Therefore, the maintenance plan SIP 
revision submitted by TDEC for the Tennessee portion of the Chattanooga 
TN-GA-AL Area meets the requirements of section 175A of the CAA and is 
approvable.

VI. What is the effect of the January 4, 2013, D.C. Circuit decision 
regarding PM2.5 implementation under subpart 4?

a. Background

    As discussed in Section I of this action, the D.C. Circuit remanded 
the 1997 PM2.5 Implementation Rule to EPA on January 4, 
2013, in Natural Resources Defense Council v. EPA, 706 F.3d 428. The 
court found that EPA erred in implementing the 1997 PM2.5 
NAAQS pursuant to the general implementation provisions of subpart 1 of 
part D of Title I of the CAA rather than the particulate matter-
specific provisions of subpart 4 of part D of Title I.

b. Proposal on This Issue

    In this portion of the proposed redesignation, EPA addresses the 
effect of the Court's January 4, 2013, ruling on the proposed 
redesignation. As explained below, EPA is proposing to determine that 
the Court's January 4, 2013, decision does not prevent EPA from 
redesignating the Tennessee portion of the Chattanooga TN-GA-AL Area to 
attainment. Even in light of the Court's decision, redesignation for 
this area is appropriate under the CAA and EPA's longstanding 
interpretations of the CAA's provisions regarding redesignation. EPA 
first explains its longstanding interpretation that requirements that 
are imposed, or that become due, after a complete redesignation request 
is submitted for an area that is attaining the standard, are not 
applicable for purposes of evaluating a redesignation request. Second, 
EPA then shows that, even if EPA applies the subpart 4 requirements to 
the Tennessee portion of the Chattanooga TN-GA-AL Area redesignation 
request and disregards the provisions of its 1997 PM2.5 
Implementation Rule remanded by the Court, the State's request for 
redesignation of the Tennessee portion of the Chattanooga TN-GA-AL Area 
still qualifies for approval. EPA's discussion takes into account the 
effect of the Court's ruling on the maintenance plan for the Tennessee 
portion of the Chattanooga TN-GA-AL Area, which EPA views as approvable 
when subpart 4 requirements are considered.

c. Applicable Requirements for the Purpose of Evaluating the 
Redesignation Request

    With respect to the 1997 PM2.5 Implementation Rule, the 
Court's January 4, 2013, ruling rejected EPA's reasons for implementing 
the PM2.5 NAAQS solely in accordance with the provisions of 
subpart 1 and remanded that matter to EPA to address implementation of 
the 1997 PM2.5 NAAQS under subpart 4 of part D of the CAA, 
in addition to subpart 1. For the purposes of evaluating Tennessee's 
redesignation request for the Tennessee portion of the Chattanooga TN-
GA-AL Area, to the extent that implementation under subpart 4 would 
impose additional requirements for areas designated nonattainment, EPA 
believes that those requirements are not ``applicable'' for the 
purposes of CAA section 107(d)(3)(E), and thus EPA is not required to 
consider subpart 4 requirements with respect to the redesignation of 
the Tennessee portion of the Chattanooga TN-GA-AL Area. Under its 
longstanding interpretation of the CAA, EPA has interpreted section 
107(d)(3)(E) to mean, as a threshold matter, that the part D provisions 
which are ``applicable'' and which must be approved in order for EPA to 
redesignate an area include only those which came due prior to a 
state's submittal of a complete redesignation request. See ``Procedures 
for Processing Requests to Redesignate Areas to Attainment,'' 
Memorandum from John Calcagni, Director, Air Quality Management 
Division, September 4, 1992 (Calcagni memorandum). See also ``State 
Implementation Plan (SIP) Requirements for Areas Submitting Requests 
for the plan and Redesignation to Attainment of the Ozone and Carbon 
Monoxide (CO) National Ambient Air Quality Standards (NAAQS) on or 
after November 15, 1992,'' Memorandum from Michael Shapiro, Acting 
Assistant Administrator, Air and Radiation, September 17, 1993 (Shapiro 
memorandum); Final Redesignation of Detroit-Ann Arbor, (60 FR 12459, 
12465-66, March 7, 1995); Final Redesignation of St. Louis, Missouri, 
(68 FR 25418, 25424-27, May 12, 2003); Sierra Club v. EPA, 375 F.3d 
537, 541 (7th Cir. 2004) (upholding EPA's redesignation rulemaking 
applying this interpretation and expressly rejecting Sierra Club's view 
that the meaning of ``applicable'' under the statute is ``whatever 
should have been in the plan at the time of attainment rather than 
whatever actually was in already implemented or due at the time of 
attainment'').\8\ In this case, at the time that Tennessee submitted 
its redesignation request on November 13, 2014, requirements under 
subpart 4 were not due.
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    \8\ Applicable requirements of the CAA that come due subsequent 
to the area's submittal of a complete redesignation request remain 
applicable until a redesignation is approved, but are not required 
as a prerequisite to redesignation. Section 175A(c) of the CAA.
---------------------------------------------------------------------------

    EPA's view that, for purposes of evaluating the Tennessee portion 
of the Chattanooga TN-GA Area redesignation, the subpart 4 requirements 
were not due at the time the State submitted the redesignation request 
is in keeping with the EPA's interpretation of subpart 2 requirements 
for subpart 1 ozone areas redesignated subsequent to the D.C. Circuit's 
decision in South Coast Air Quality Mgmt. Dist. v. EPA, 472 F.3d 882 
(D.C. Cir. 2006). In South Coast, the Court found that EPA was not 
permitted to implement the 1997 8-hour ozone standard solely under 
subpart 1 and held that EPA was required under the statute to implement 
the standard under the ozone-specific requirements of subpart 2 as 
well. Subsequent to the South Coast decision, in evaluating and acting 
upon redesignation requests for the 1997 8-hour ozone standard that 
were submitted to EPA for areas under subpart 1, EPA applied its 
longstanding interpretation of the CAA that ``applicable 
requirements,'' for purposes of evaluating a redesignation, are those 
that had been due at the time the redesignation request was submitted.

[[Page 16342]]

See, e.g., Proposed Redesignation of Manitowoc County and Door County 
Nonattainment Areas (75 FR 22047, 22050, April 27, 2010). In those 
actions, EPA therefore did not consider subpart 2 requirements to be 
``applicable'' for the purposes of evaluating whether the area should 
be redesignated under section 107(d)(3)(E).
    EPA's interpretation derives from the provisions of CAA Section 
107(d)(3)(E). Section 107(d)(3)(E)(v) states that, for an area to be 
redesignated, a state must meet ``all requirements `applicable' to the 
area under section 110 and part D.'' Section 107(d)(3)(E)(ii) provides 
that the EPA must have fully approved the ``applicable'' SIP for the 
area seeking redesignation. These two sections read together support 
EPA's interpretation of ``applicable'' as only those requirements that 
came due prior to submission of a complete redesignation request. 
First, holding states to an ongoing obligation to adopt new CAA 
requirements that arose after the state submitted its redesignation 
request, in order to be redesignated, would make it problematic or 
impossible for EPA to act on redesignation requests in accordance with 
the 18-month deadline Congress set for EPA action in section 
107(d)(3)(D). If ``applicable requirements'' were interpreted to be a 
continuing flow of requirements with no reasonable limitation, states, 
after submitting a redesignation request, would be forced continuously 
to make additional SIP submissions that in turn would require EPA to 
undertake further notice-and-comment rulemaking actions to act on those 
submissions. This would create a regime of unceasing rulemaking that 
would delay action on the redesignation request beyond the 18-month 
timeframe provided by the Act for this purpose.
    Second, a fundamental premise for redesignating a nonattainment 
area to attainment is that the area has attained the relevant NAAQS due 
to emission reductions from existing controls. Thus, an area for which 
a redesignation request has been submitted would have already attained 
the NAAQS as a result of satisfying statutory requirements that came 
due prior to the submission of the request. Absent a showing that 
unadopted and unimplemented requirements are necessary for future 
maintenance, it is reasonable to view the requirements applicable for 
purposes of evaluating the redesignation request as including only 
those SIP requirements that have already come due. These are the 
requirements that led to attainment of the NAAQS. To require, for 
redesignation approval, that a state also satisfy additional SIP 
requirements coming due after the state submits its complete 
redesignation request, and while EPA is reviewing it, would compel the 
state to do more than is necessary to attain the NAAQS, without a 
showing that the additional requirements are necessary for maintenance.

d. Subpart 4 Requirements and the Tennessee Portion of the Chattanooga 
TN-GA-AL Area Redesignation Request

    Even if EPA were to take the view that the Court's January 4, 2013, 
decision requires that, in the context of pending redesignations, 
subpart 4 requirements were due and in effect at the time the State 
submitted its redesignation request, EPA proposes to determine that the 
Tennessee portion of the Chattanooga TN-GA-AL Area still qualifies for 
redesignation to attainment. As explained below, EPA believes that the 
redesignation request for the Tennessee portion of the Chattanooga TN-
GA Area, though not expressed in terms of subpart 4 requirements, 
substantively meets the requirements of that subpart for purposes of 
redesignating the Tennessee portion of the Chattanooga TN-GA Area to 
attainment.
    With respect to evaluating the relevant substantive requirements of 
subpart 4 for purposes of redesignating the Tennessee portion of the 
Chattanooga TN-GA-AL Area, EPA notes that subpart 4 incorporates 
components of subpart 1 of part D, which contains general air quality 
planning requirements for areas designated as nonattainment. See 
section 172(c). Subpart 4 itself contains specific planning and 
scheduling requirements for PM10 \9\ nonattainment areas, 
and under the Court's January 4, 2013, decision in NRDC v. EPA, these 
same statutory requirements also apply for PM2.5 
nonattainment areas. EPA has longstanding general guidance that 
interprets the 1990 amendments to the CAA, making recommendations to 
states for meeting the statutory requirements for SIPs for 
nonattainment areas.\10\ In the General Preamble, 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. The subpart 1 requirements include, among other things, 
provisions for attainment demonstrations, RACM, RFP, emissions 
inventories, and contingency measures.
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    \9\ PM10 refers to particles nominally 10 micrometers 
in diameter or smaller.
    \10\ See ``State Implementation Plans; General Preamble for the 
Implementation of Title I of the Clean Air Act Amendments of 1990,'' 
57 FR 13498 (April 16, 1992) (the ``General Preamble'').
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    For the purposes of this redesignation, in order to identify any 
additional requirements which would apply under subpart 4, EPA is 
considering the Tennessee portion of the Chattanooga TN-GA-AL Area to 
be a ``moderate'' PM2.5 nonattainment area. Under section 
188 of the CAA, all areas designated nonattainment areas under subpart 
4 would initially be classified by operation of law as ``moderate'' 
nonattainment areas and would remain moderate nonattainment areas 
unless and until EPA reclassifies the area as a ``serious'' 
nonattainment area. Accordingly, EPA believes that it is appropriate to 
limit the evaluation of the potential impact of subpart 4 requirements 
to those that would be applicable to moderate nonattainment areas. 
Sections 189(a) and (c) of subpart 4 apply to moderate nonattainment 
areas and include the following: (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)); and (4) quantitative 
milestones demonstrating RFP toward attainment by the applicable 
attainment date (section 189(c)).
    The permit requirements of subpart 4, as 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.\11\ In any 
event, in the context of redesignation, 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 a 
memorandum from Mary Nichols, Assistant Administrator for Air and 
Radiation, dated October 14, 1994, entitled ``Part D New Source Review 
Requirements for Areas Requesting Redesignation to Attainment.'' See 
also rulemakings for Detroit, Michigan (60 FR 12467-12468, March 7, 
1995); Cleveland-Akron-Lorain, Ohio (61 FR 20458, 20469-20470, May 7, 
1996); Louisville, Kentucky (66 FR 53665,

[[Page 16343]]

October 23, 2001); and Grand Rapids, Michigan (61 FR 31834-31837, June 
21, 1996).
---------------------------------------------------------------------------

    \11\ The potential effect of section 189(e) on section 
189(a)(1)(A) for purposes of evaluating this redesignation is 
discussed below.
---------------------------------------------------------------------------

    With respect to the specific attainment planning requirements under 
subpart 4,\12\ when EPA evaluates a redesignation request under either 
subpart 1 or 4, any area that is attaining the PM2.5 
standard is viewed as having satisfied the attainment planning 
requirements for these subparts. As discussed above, for 
redesignations, EPA has for many years interpreted attainment-linked 
requirements as not applicable for areas attaining the standard.
---------------------------------------------------------------------------

    \12\ i.e., attainment demonstration, RFP milestone requirements, 
and RACM.
---------------------------------------------------------------------------

    Therefore, even if we were to consider the Court's January 4, 2013, 
decision in NRDC v. EPA to mean that attainment-related requirements 
specific to subpart 4 should be imposed retroactively \13\ and thus are 
now past due, those requirements do not apply to an area that is 
attaining the 1997 PM2.5 standard for the purpose of 
evaluating a pending request to redesignate the area to attainment.
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    \13\ As explained above, EPA does not believe that the Court's 
January 4, 2013, decision should be interpreted so as to impose 
these requirements on the states retroactively. Sierra Club v. 
Whitman, supra.
---------------------------------------------------------------------------

    Elsewhere in this document, EPA proposes to determine that the Area 
has attained the 1997 PM2.5 standard. Under its longstanding 
interpretation, EPA is proposing to determine here that the Area meets 
the attainment-related plan requirements of subparts 1 and 4.
    Thus, EPA is proposing to conclude that the requirements to submit 
an attainment demonstration under 189(a)(1)(B), a RACM determination 
under section 189(a)(1)(C), and a RFP demonstration under 189(c)(1) are 
satisfied for purposes of evaluating the redesignation request.

e. Subpart 4 and Control of PM2.5 Precursors

    The D.C. Circuit in NRDC v. EPA remanded to EPA the two rules at 
issue in the case with instructions to EPA to re-promulgate them 
consistent with the requirements of subpart 4. EPA in this section 
addresses the Court's opinion with respect to PM2.5 
precursors. While past implementation of subpart 4 for PM10 
has allowed for control of PM10 precursors such as 
NOX from major stationary, mobile, and area sources in order 
to attain the standard as expeditiously as practicable, CAA section 
189(e) specifically provides that control requirements for major 
stationary sources of direct PM10 shall also apply to 
PM10 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.''
    EPA's 1997 PM2.5 implementation rule, remanded by the 
D.C. Circuit, contained rebuttable presumptions concerning certain 
PM2.5 precursors applicable to attainment plans and control 
measures related to those plans. Specifically, in 40 CFR 51.1002, EPA 
provided, among other things, that a state was ``not required to 
address VOC [and ammonia] as . . . PM2.5 attainment plan 
precursor[s] and to evaluate sources of VOC [and ammonia] emissions in 
the State for control measures.'' EPA intended these to be rebuttable 
presumptions. EPA established these presumptions at the time because of 
uncertainties regarding the emission inventories for these pollutants 
and the effectiveness of specific control measures in various regions 
of the country in reducing PM2.5 concentrations. EPA also 
left open the possibility for such regulation of VOC and ammonia in 
specific areas where that was necessary.
    The Court in its January 4, 2013, decision made reference to both 
section 189(e) and 40 CFR 51.1002, and stated that, ``In light of our 
disposition, we need not address the petitioners' challenge to the 
presumptions in [40 CFR 51.1002] that volatile organic compounds and 
ammonia are not PM2.5 precursors, as subpart 4 expressly 
governs precursor presumptions.'' NRDC v. EPA, at 27, n.10.
    Elsewhere in the Court's opinion, however, the Court observed: 
Ammonia is a precursor to fine particulate matter, making it a 
precursor to both PM2.5 and PM10. For a 
PM10 nonattainment area governed by subpart 4, a precursor 
is presumptively regulated. See 42 U.S.C. 7513a(e) [section 189(e)]. 
Id. at 21, n.7.
    For a number of reasons, EPA believes that its proposed 
redesignation of the Tennessee portion of the Chattanooga TN-GA-AL Area 
is consistent with the Court's decision on this aspect of subpart 4. 
First, while the Court, citing section 189(e), stated that ``for a 
PM10 area governed by subpart 4, a precursor is 
`presumptively regulated,' '' the Court expressly declined to decide 
the specific challenge to EPA's 1997 PM2.5 implementation 
rule provisions regarding ammonia and VOC as precursors. The Court had 
no occasion to determine whether and how it was substantively necessary 
to regulate any specific precursor in a particular PM2.5 
nonattainment area, and did not address what might be necessary for 
purposes of acting upon a redesignation request.
    However, even if EPA takes the view that the requirements of 
subpart 4 were deemed applicable at the time that the state submitted 
the redesignation request, and disregards the implementation rule's 
rebuttable presumptions regarding ammonia and VOC as PM2.5 
precursors, the regulatory consequence would be to consider the need 
for regulation of all precursors from any sources in the area to 
demonstrate attainment and to apply the section 189(e) provisions to 
major stationary sources of precursors. In the case of the Chattanooga 
TN-GA-AL Area, EPA believes that doing so is consistent with proposing 
redesignation of the area for the PM2.5 standard. The 
Chattanooga TN-GA-AL Area has attained the standard without any 
specific additional controls of VOC and ammonia emissions from any 
sources in the Area.
    Precursors in subpart 4 are specifically regulated under the 
provisions of section 189(e), which requires, with important 
exceptions, control requirements for major stationary sources of 
PM10 precursors.\14\ Under subpart 1 and EPA's prior 
implementation rule, all major stationary sources of PM2.5 
precursors were subject to regulation, with the exception of ammonia 
and VOC. Thus, EPA must address here whether additional controls of 
ammonia and VOC from major stationary sources are required under 
section 189(e) of subpart 4 in order to redesignate the area for the 
1997 PM2.5 standard. As explained below, EPA does not 
believe that any additional controls of ammonia and VOC are required in 
the context of this redesignation.
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    \14\ Under either subpart 1 or subpart 4, for purposes of 
demonstrating attainment as expeditiously as practicable, a state is 
required to evaluate all economically and technologically feasible 
control measures for direct PM emissions and precursor emissions, 
and adopt those measures that are deemed reasonably available.
---------------------------------------------------------------------------

    In the General Preamble, EPA discusses its approach to implementing 
section 189(e). See 57 FR 13538 (April 16, 1992). With regard to 
precursor regulation under section 189(e), the General Preamble 
explicitly stated that control of VOCs under other Act requirements may 
suffice to relieve a state from the need to adopt precursor controls 
under section 189(e). See 57 FR 13542. EPA in this rulemaking proposes 
to determine that even if not explicitly addressed by the State in its 
submission, the State does not need to take further action with respect 
to ammonia and VOCs as precursors to satisfy the requirements of 
section 189(e). This proposed determination is based on our

[[Page 16344]]

findings that: (1) The Tennessee portion of the Chattanooga TN-GA-AL 
Area contains no major stationary sources of ammonia, and (2) existing 
major stationary sources of VOC are adequately controlled under other 
provisions of the CAA regulating the ozone NAAQS.\15\ In the 
alternative, EPA proposes to determine that, under the express 
exception provisions of section 189(e), and in the context of the 
redesignation of the Area, which is attaining the 1997 Annual 
PM2.5 standard, at present ammonia and VOC precursors from 
major stationary sources do not contribute significantly to levels 
exceeding the 1997 PM2.5 standard in the Chattanooga TN-GA-
AL Area. See 57 FR 13539.
---------------------------------------------------------------------------

    \15\ The Chattanooga TN-GA-AL Area has reduced VOC emissions 
through the implementation of various control programs including 
various on-road and non-road motor vehicle control programs.
---------------------------------------------------------------------------

    EPA notes that its 1997 PM2.5 implementation rule 
provisions in 40 CFR 51.1002 were not directed at evaluation of 
PM2.5 precursors in the context of redesignation, but rather 
the rule assesses SIP plans and control measures required to bring a 
nonattainment area into attainment of the 1997 PM2.5 NAAQS. 
By contrast, redesignation to attainment primarily requires the area to 
have already attained due to permanent and enforceable emission 
reductions, and to demonstrate that controls in place can continue to 
maintain the standard. Thus, even if EPA regards the Court's January 4, 
2013, decision as calling for ``presumptive regulation'' of ammonia and 
VOC for PM2.5 under the attainment planning provisions of 
subpart 4, those provisions in and of themselves do not require 
additional controls of these precursors for an area that already 
qualifies for redesignation. Nor does EPA believe that requiring the 
State to address precursors differently than they have already would 
result in a substantively different outcome.
    Although, as EPA has emphasized, its consideration here of 
precursor requirements under subpart 4 is in the context of a 
redesignation to attainment, EPA's existing interpretation of subpart 4 
requirements with respect to precursors in attainment plans for 
PM10 contemplates that states may develop attainment plans 
that regulate only those precursors that are necessary for purposes of 
attainment in the area in question, i.e., states may determine that 
only certain precursors need be regulated for attainment and control 
purposes.\16\ Courts have upheld this approach to the requirements of 
subpart 4 for PM10.\17\ EPA believes that application of 
this approach to PM2.5 precursors under subpart 4 is 
reasonable. Because the Chattanooga TN-GA-AL Area has already attained 
the 1997 PM2.5 NAAQS with its current approach to regulation 
of PM2.5 precursors, EPA believes that it is reasonable to 
conclude in the context of this redesignation that there is no need to 
revisit the attainment control strategy with respect to the treatment 
of precursors. Even if the Court's decision is construed to impose an 
obligation, in evaluating this redesignation request, to consider 
additional precursors under subpart 4, it would not affect EPA's 
approval here of Tennessee's request for redesignation of the Tennessee 
portion of the Chattanooga TN-GA-AL Area. In the context of a 
redesignation, Tennessee has shown that the Chattanooga TN-GA-AL Area 
has attained the standard. Moreover, the State has shown, and EPA has 
proposed to determine, that attainment in this Area is due to permanent 
and enforceable emissions reductions on all precursors necessary to 
provide for continued attainment. It follows logically that no further 
control of additional precursors is necessary. Accordingly, EPA does 
not view the January 4, 2013, decision of the court as precluding 
redesignation of the Tennessee portion of the Chattanooga TN-GA-AL Area 
to attainment for the 1997 Annual PM2.5 NAAQS at this time. 
In sum, even if Tennessee were required to address precursors for the 
Tennessee portion of the Chattanooga TN-GA-AL Area under subpart 4 
rather than under subpart 1, EPA would still conclude that the Area had 
met all applicable requirements for purposes of redesignation in 
accordance with section 107(d)(3(E)(ii) and (v).
---------------------------------------------------------------------------

    \16\ See ``Approval and Promulgation of Implementation Plans for 
California--San Joaquin Valley PM-10 Nonattainment Area; Serious 
Area Plan for Nonattainment of the 24-Hour and Annual PM-10 
Standards,'' 69 FR 30006 (May 26, 2004) (approving a PM10 
attainment plan that impose controls on direct PM10 and 
NOX emissions and did not impose controls on 
SO2, VOC, or ammonia emissions).
    \17\ See Association of Irritated Residents v. EPA et al., 423 
F.3d 989 (9th Cir. 2005).
---------------------------------------------------------------------------

f. Maintenance Plan and Evaluation of Precursors

    With regard to the redesignation of the Tennessee portion of the 
Chattanooga TN-GA-AL Area, in evaluating the effect of the Court's 
remand of EPA's implementation rule, which included presumptions 
against consideration of VOC and ammonia as PM2.5 
precursors, EPA in this proposal is also considering the impact of the 
decision on the maintenance plan required under sections 175A and 
107(d)(3)(E)(iv). To begin with, EPA notes that the Area has attained 
the 1997 Annual PM2.5 NAAQS and that the State has shown 
that attainment of that standard is due to permanent and enforceable 
emission reductions.
    EPA proposes to determine that the State's maintenance plan shows 
continued maintenance of the standard by tracking the levels of the 
precursors whose control brought about attainment of the 1997 
PM2.5 standard in the Chattanooga TN-GA-AL Area. EPA 
therefore believes that the only additional consideration related to 
the maintenance plan requirements that results from the Court's January 
4, 2013, decision is that of assessing the potential role of VOC and 
ammonia in demonstrating continued maintenance in this area. As 
explained below, based upon documentation provided by Tennessee and 
supporting information, EPA believes that the maintenance plan for the 
Tennessee portion of the Chattanooga TN-GA-AL Area need not include any 
additional emission reductions of VOC or ammonia in order to provide 
for continued maintenance of the standard.
    First, as noted above in EPA's discussion of section 189(e), VOC 
emission levels in this area have historically been well-controlled 
under SIP requirements related to ozone and other pollutants. Second, 
total ammonia emissions throughout the Tennessee portion of the 
Chattanooga TN-GA-AL area are low, estimated to be approximately 370.9 
tpy for 2007. See Table 7 below. As described below, available 
information shows that no precursor, including VOC and ammonia, is 
expected to increase significantly over the maintenance period so as to 
interfere with or undermine the State's maintenance demonstration.

[[Page 16345]]

  Table 7--Comparison of 2007 and 2020 VOC and Ammonia Emission Totals by Source Sector (tpy) for the Tennessee
                                             Portion of the Area 18
----------------------------------------------------------------------------------------------------------------
                                                     VOC                                  Ammonia
           Source sector           -----------------------------------------------------------------------------
                                        2007         2020      Net change      2007         2020      Net change
----------------------------------------------------------------------------------------------------------------
Nonpoint..........................      5,338.9      5,372.1         33.3        194.2        202.0          7.8
Nonroad...........................      2,383.3      1,213.3        -1170          2.7          3.1          0.4
Onroad............................      4,797.5      1,541.8      -3255.7        161.6         92.5        -69.1
Point.............................      1,047.0      1,038.1         -8.9         12.5         12.5            0
                                   -----------------------------------------------------------------------------
    Total.........................     13,566.6      9,165.4     -4,401.2        370.9        310.1        -60.8
----------------------------------------------------------------------------------------------------------------

    Tennessee's  maintenance plan shows that emissions of 
SO2, NOX, and PM2.5 are projected to 
decrease over the maintenance period in the Tennessee portion of the 
Chattanooga TN-GA-AL Area by 91.9 tpy, 7,890.4 tpy and 116.5 tpy, 
respectively. See Table 6 above. In addition, emissions inventories 
used in the regulatory impact analysis (RIA) for the 2012 
PM2.5 NAAQS show that VOC emissions are projected to 
decrease by 4,401.2 tpy and that ammonia emissions are projected to 
decrease by 60.8 tpy between 2007 and 2020. While the RIA emissions 
inventories are only projected out to 2020, there is no reason to 
believe that this overall downward trend would not continue through 
2025. Given that the Chattanooga TN-GA-AL Area is already attaining the 
1997 Annual PM2.5 NAAQS even with the current level of 
emissions from sources in the Area, the overall downward trend of 
emissions inventories is consistent with continued attainment. Even if 
VOC and ammonia emissions were to increase unexpectedly between 2020 
and 2025, the overall emission reductions projected in SO2 
and NOX would be sufficient to offset any increases. For 
these reasons, EPA believes that local emissions of all the potential 
PM2.5 precursors will not increase to the extent that they 
might cause monitored PM2.5 levels to violate the 1997 
Annual PM2.5 standard during the maintenance period.
---------------------------------------------------------------------------

    \18\ These emissions estimates were taken from the emissions 
inventories developed for the regulatory impact analysis for the 
2012 PM2.5 NAAQS.
---------------------------------------------------------------------------

    In addition, available air quality data and modeling analyses show 
continued maintenance of the standard during the maintenance period. As 
noted in section V, above, the Chattanooga TN-GA-AL Area recorded a 
PM2.5 design value of 10.5 [mu]g/m\3\ during 2011-2013, the 
most recent three years available with complete, quality-assured and 
certified ambient air monitoring data. This is well below the 1997 
Annual PM2.5 NAAQS of 15 [mu]g/m\3\. Moreover, the modeling 
analysis conducted for the RIA for the 2012 PM2.5 NAAQS 
indicates that the design value for this area is expected to continue 
to decline through 2020. Given the decrease in overall precursor 
emissions projected through 2025, it is reasonable to conclude that 
monitored PM2.5 levels in this area will also continue to 
decrease through 2025.
    Thus, EPA believes that there is ample justification to conclude 
that the Tennessee portion of the Chattanooga TN-GA-AL Area should be 
redesignated, even taking into consideration the emissions of VOC and 
ammonia potentially relevant to PM2.5. After consideration 
of the D.C. Circuit's January 4, 2013, decision, and for the reasons 
set forth in this document, EPA continues to propose approval of the 
State's maintenance plan and its request to redesignate the Tennessee 
portion of the Chattanooga TN-GA-AL Area to attainment for the 1997 
Annual PM2.5 NAAQS.

VII. What is EPA's analysis of Tennessee's proposed NOX and 
PM2.5 MVEBs for the Tennessee portion of the Chattanooga TN-
GA-AL area?

    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 the 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 MVEBs is the portion of the total allowable emissions in 
the maintenance demonstration that is allocated to highway and transit 
vehicle use and emissions. See 40 CFR 93.101. The MVEBs serves as a 
ceiling on emissions from an area's planned transportation system. The 
MVEBs concept is further explained in the preamble to the November 24, 
1993, Transportation Conformity Rule. See 58 FR 62188. The preamble 
also describes how to establish the MVEBs in the SIP and how to revise 
the MVEBs.
    After interagency consultation with the transportation partners for 
the Tennessee portion of the Chattanooga TN-GA-AL Area, Tennessee has 
elected to develop MVEBs for NOX and PM2.5 for 
the entire nonattainment area. Tennessee has developed these MVEBs, as 
required, for the last year of its maintenance plan, 2025. The MVEBs 
reflect the total on-road emissions for 2025, 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

[[Page 16346]]

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. The NOX and 
PM2.5 MVEBs for the Tennessee portion of the Chattanooga TN-
GA-AL Area are defined in Table 8 below.

  Table 8--Tennessee Portion of the Chattanooga TN-GA-AL Area PM2.5 and
                                NOX MVEBs
                                  [tpy]
------------------------------------------------------------------------
                                                       PM2.5       NOX
------------------------------------------------------------------------
2025 Mobile Emissions..............................       76.5   2,508.7
2025 Safety Margin Allocated.......................       23.5     691.3
                                                    --------------------
    2025 Total Mobile Budget.......................      100.0   3,200.0
------------------------------------------------------------------------

    In an effort to accommodate future variations in Travel Demand 
Models (TDM) and the vehicle miles traveled forecast when no change to 
the network is planned, TDEC consulted with the interagency 
consultation group, including EPA, to determine a reasonable approach 
to address this variation. The projected 2025 on-road motor vehicle 
emissions for direct PM2.5 and NOX are 76.5 tpy 
and 2,508.7 tpy, respectively. On-road emissions of SO2 are 
considered de-minimus; therefore, no budget for SO2 is 
required.\19\
---------------------------------------------------------------------------

    \19\ 70 FR 24280, 24283 (May 6, 2005) (``While speciated air 
quality data show that sulfate is a relatively significant component 
(e.g., ranging from nine to 40 percent) of PM2.5 mass in 
all regions of the country, emissions inventory data and projections 
show that on-road emissions of SOX constitute a ``de 
minimis'' (i.e., extremely small) portion of total SOX 
emissions.'').
---------------------------------------------------------------------------

    A safety margin is necessary to accommodate the variabilities, or 
worst-case scenarios that can occur due to future planning assumptions. 
The worst-case daily motor vehicle emissions projection for 
PM2.5 is 23.5 tpy above the projected 2025 on-road 
emissions. In a worst-case scenario, the needed annual safety margin 
for the PM2.5 MVEB would be 23.5 tpy resulting in an overall 
MVEB of 100.0 tpy. The worst-case daily motor vehicle emissions 
projection for NOX is 691.3 tpy above the projected 2025 on-
road emissions. In a worst-case scenario, the required annual safety 
margin for the NOX MVEB would be 691.3 tpy resulting in an 
overall MVEB of 3,200.0 tpy.
    Through this rulemaking, EPA is proposing to approve the MVEBs for 
NOX and PM2.5 for 2025 for the 
Tennessee portion of the Chattanooga TN-GA-AL Area because EPA has 
determined that the Area maintains the 1997 Annual PM2.5 
NAAQS with the emissions at the levels of the budgets. Once the MVEBs 
for the Tennessee portion of the Chattanooga TN-GA-AL Area are approved 
or found adequate (whichever is completed first), they must be used for 
future conformity determinations. After thorough review, EPA has 
determined that the budgets meet the adequacy criteria, as outlined in 
40 CFR 93.118(e)(4). Therefore, EPA is proposing to approve the budgets 
because they are consistent with maintenance of the 1997 Annual 
PM2.5 NAAQS through 2025.

VIII. What is the status of EPA's adequacy determination for the 
proposed NOX and PM2.5 MVEBs for 2025 for the 
Tennessee portion of the Chattanooga TN-GA-AL area?

    When reviewing submitted ``control strategy'' SIPs or maintenance 
plans containing MVEB, EPA may affirmatively find the MVEB contained 
therein adequate for use in determining transportation conformity. Once 
EPA affirmatively finds the submitted MVEB is adequate for 
transportation conformity purposes, that MVEBs must be used by state 
and federal agencies in determining whether proposed transportation 
projects conform to the SIP as required by section 176(c) of the CAA.
    EPA's substantive criteria for determining adequacy of MVEBs are 
set out in 40 CFR 93.118(e)(4). The process for determining adequacy 
consists of three basic steps: Public notification of a SIP submission, 
a public comment period, and EPA's adequacy determination. This process 
for determining the adequacy of submitted MVEBs for transportation 
conformity purposes was initially outlined in EPA's May 14, 1999, 
guidance entitled ``Conformity Guidance on Implementation of March 2, 
1999, Conformity Court Decision.'' EPA adopted regulations to codify 
the adequacy process in rulemaking entitled Transportation Conformity 
Rule Amendments for the ``New 8-Hour Ozone and PM2.5 
National Ambient Air Quality Standards and Miscellaneous Revisions for 
Existing Areas; Transportation Conformity Rule Amendments: Response to 
Court Decision and Additional Rule Change''; July 1, 2004 (69 FR 
40004). Additional information on the adequacy process for 
transportation conformity purposes is available in the proposed rule 
entitled ``Transportation Conformity Rule Amendments: Response to Court 
Decision and Additional Rule Changes''; June 30, 2003 (68 FR 38974, 
38984).
    As discussed earlier, Tennessee's maintenance plan submission 
includes NOX and PM2.5 MVEBs for the Tennessee 
portion of the Chattanooga TN-GA-AL Area for 2025, the last year of the 
maintenance plan. EPA reviewed the NOX and PM2.5 
MVEBs through the adequacy process, and the adequacy of the MVEBs was 
open for public comment on EPA's adequacy Web site on December 9, 2014, 
found at: http://www.epa.gov/otaq/stateresources/transconf/currsips.htm. The EPA public comment period on adequacy for the MVEBs 
for 2025 for the Tennessee portion of the Chattanooga TN-GA-AL Area 
closed on January 8, 2015. EPA did not receive any comments on the 
adequacy of the MVEBs, nor did EPA receive any requests for the SIP 
submittal.
    EPA intends to make its determination on the adequacy of the 2025 
MVEBs for the Tennessee portion of the Chattanooga TN-GA-AL Area for 
transportation conformity purposes in the near future by completing the 
adequacy process that was started on December 9, 2014. After EPA finds 
the 2025 MVEBs adequate under 40 CFR 93.118(f)(1)(iv) or take final 
action to approve them into the Tennessee SIP under 40 CFR 
93.118(f)(2)(iii), the new MVEBs for NOX and 
PM2.5 must be used for future transportation conformity 
determinations. For required regional emissions analysis years that 
involve 2025 or beyond, the applicable budgets will be the new 2025 
MVEBs established in the maintenance plan.

IX. Proposed Actions on the Redesignation Request and Maintenance Plan 
SIP Revisions Including Approval of the NOX and 
PM2.5 MVEBs for 2025 for the Tennessee Portion of the 
Chattanooga TN-GA-AL Area

    On May 31, 2011, EPA determined that the Chattanooga TN-GA Area was 
attaining the 1997 PM2.5 NAAQS. See 76 FR 55774. EPA is now 
taking two separate but related actions regarding the Area's 
redesignation and maintenance of the 1997 Annual PM2.5 
NAAQS.
    First, EPA is proposing to determine that, based upon review of 
complete, quality-assured and certified ambient monitoring data for the 
2007-2009 period, and review of data in AQS for 2010 through 2013, that 
the Chattanooga TN-GA-AL Area continues to attain the 1997 Annual 
PM2.5 NAAQS. EPA is also proposing to determine that the 
Tennessee portion of the Chattanooga TN-GA-AL Area has met the criteria

[[Page 16347]]

under CAA section 107(d)(3)(E) for redesignation from nonattainment to 
attainment for the 1997 Annual PM2.5 NAAQS. On this basis, 
EPA is proposing to approve Tennessee's redesignation request for the 
Tennessee portion of the Chattanooga TN-GA-AL Area.
    Second, EPA is proposing to approve the maintenance plan for the 
Tennessee portion of the Chattanooga TN-GA-AL Area, including the 
PM2.5 and NOX MVEBs for 2025 submitted by 
Tennessee into the State's SIP (under section 175A). The maintenance 
plan demonstrates that the Area will continue to maintain the 1997 
Annual PM2.5 NAAQS, and the budgets meet all of the adequacy 
criteria contained in 40 CFR 93.118(e)(4) and (5). Further, as part of 
today's action, EPA is describing the status of its adequacy 
determination for transportation conformity purposes for the 
PM2.5 and NOX MVEBs for 2025 under 40 CFR 
93.118(f)(1). Within 24 months from the effective date of EPA's 
adequacy determination for the MVEBs or the effective date for the 
final rule approving the MVEBs into the Tennessee SIP, whichever is 
earlier, the transportation partners will need to demonstrate 
conformity to the new NOX and PM2.5 MVEBs 
pursuant to 40 CFR 93.104(e).
    If finalized, approval of the redesignation request would change 
the official designation of Tennessee portion of the Chattanooga TN-GA-
AL Area for the 1997 Annual PM2.5 NAAQS, found at 40 CFR 
part 81 from nonattainment to attainment.

X. 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 today. Approval 
of Tennessee's redesignation request would change the legal designation 
of Hamilton County in Tennessee for the 1997 Annual PM2.5 
NAAQS, found at 40 CFR part 81, from nonattainment to attainment. 
Approval of TDEC's request would also incorporate a plan for 
maintaining the 1997 Annual PM2.5 NAAQS in the Chattanooga 
TN-GA-AL Area through 2025 into the Tennessee SIP. The maintenance plan 
includes contingency measures to remedy any future violations of the 
1997 Annual PM2.5 NAAQS and procedures for evaluation of 
potential violations. The maintenance plan also includes NOX 
and PM2.5 MVEBs for the Tennessee portion of the Chattanooga 
TN-GA-AL Area. Additionally, EPA is notifying the public of the status 
of its adequacy determination for the NOX and 
PM2.5 MVEBs for 2025 under 40 CFR 93.118(f)(1).

XI. 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. 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 state law as meeting 
federal requirements and do not impose additional requirements beyond 
those imposed by state law. For that reason, these proposed actions:
     Is not a significant regulatory action subject to review 
by the Office of Management and Budget under Executive Orders 12866 (58 
FR 51735, October 4, 1993) and 13563 (76 FR 3821, January 21, 2011);
     Do not impose an information collection burden under the 
provisions of the Paperwork Reduction Act (44 U.S.C. 3501 et seq.);
     Are certified as not having a significant economic impact 
on a substantial number of small entities under the Regulatory 
Flexibility Act (5 U.S.C. 601 et seq.);
     Do not contain any unfunded mandate or significantly or 
uniquely affect small governments, as described in the Unfunded 
Mandates Reform Act of 1995 (Pub. L. 104-4);
     Do not have Federalism implications as specified in 
Executive Order 13132 (64 FR 43255, August 10, 1999);
     Are not economically significant regulatory actions based 
on health or safety risks subject to Executive Order 13045 (62 FR 
19885, April 23, 1997);
     Are not significant regulatory actions subject to 
Executive Order 13211 (66 FR 28355, May 22, 2001);
     Are not subject to requirements of Section 12(d) of the 
National Technology Transfer and Advancement Act of 1995 (15 U.S.C. 272 
note) because application of those requirements would be inconsistent 
with the CAA; and
     Do not provide EPA with the discretionary authority to 
address, as appropriate, disproportionate human health or environmental 
effects, using practicable and legally permissible methods, under 
Executive Order 12898 (59 FR 7629, February 16, 1994).
    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 on tribal governments or preempt tribal 
law.

List of Subjects

40 CFR Part 52

    Environmental protection, Air pollution control, Incorporation by 
reference, Intergovernmental relations, 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: March 11, 2015.
Heather McTeer Toney,
Regional Administrator, Region 4.
[FR Doc. 2015-06963 Filed 3-26-15; 8:45 am]
 BILLING CODE 6560-50-P
```