[Federal Register Volume 79, Number 218 (Wednesday, November 12, 2014)]
[Proposed Rules]
[Pages 67120-67137]
[FR Doc No: 2014-26735]

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Parts 52 and 81

[EPA-R04-OAR-2014-0267; FRL-9919-18-Region 4]

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

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.

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SUMMARY: On September 14, 2012, the Georgia Department of Natural
Resources, through the Georgia Environmental Protection Division (GA
EPD), submitted a request to redesignate the Georgia portion of the
Chattanooga, TN-GA fine particulate matter (PM2.5)
nonattainment area (hereafter referred to as the ``Chattanooga TN-GA
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 Georgia portion of the Chattanooga TN-GA Area. The Georgia portion
of the Chattanooga TN-GA Area is comprised of two counties: Catoosa and
Walker Counties in Georgia. The Environmental Protection Agency (EPA)
is proposing to approve the redesignation request and the related SIP
revision, including GA EPD's plan for maintaining attainment of the
PM2.5 standard, for the Georgia portion of the Chattanooga
TN-GA Area. EPA is also proposing to approve into the Georgia SIP the
motor vehicle emission budgets (MVEBs) for nitrogen oxides
(NOX) and PM2.5 for the year 2025 for the Georgia
portion of the Chattanooga TN-GA Area. On April 23, 2013, Alabama
submitted a request to redesignate the Alabama portion of the
Chattanooga TN-GA Area, and EPA is expecting Tennessee to submit a
request to redesignate the Tennessee portion of the Chattanooga TN-GA
Area. EPA will be taking separate action on the requests from Georgia
and Tennessee.

DATES: Comments must be received on or before December 3, 2014.

ADDRESSES: Submit your comments, identified by Docket ID No. EPA-R04-
OAR-2014-0267, by one of the following methods:
    1. www.regulations.gov: Follow the on-line instructions for
submitting comments.
    2. Email<EMAIL_ADDRESS>    3. Fax:<PHONE_NUMBER>.
    4. Mail: EPA-R04-OAR-2014-0267, Regulatory Development Section, 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,
Regulatory Development Section, Air Planning 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-
2014-0267. 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 Regulatory Development Section, Air Planning
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 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 Regulatory
Development Section, in 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. Joydeb
Majumder may be reached by phone at<PHONE_NUMBER>, or via electronic
mail at<EMAIL_ADDRESS>
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 the January 4, 2013, D.C. Circuit decision
regarding PM2.5 implementation under Subpart 4?
VII. What is EPA's analysis of Georgia's proposed NOX and
PM2.5 MVEBs for the Georgia portion of the Chattanooga
TN-GA Area?
VIII. What is the status of EPA's adequacy determination for the
proposed NOX and PM2.5 MVEBs for 2025 for the
Georgia portion of the Chattanooga TN-GA 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 Georgia
Portion of the Chattanooga TN-GA 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 Area is continuing to attain the 1997 Annual
PM2.5 NAAQS \1\ and to take additional actions related to
Georgia's request to redesignate the Georgia portion of the Chattanooga
TN-GA Area, which is summarized as follows and described in greater
detail throughout this notice of proposed rulemaking. EPA proposes: (1)
to redesignate the Georgia portion of the Chattanooga TN-GA 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),
Georgia's 1997 Annual PM2.5 NAAQS maintenance plan,
including the associated MVEBs, for the Georgia portion of the
Chattanooga TN-GA Area into the Georgia SIP.
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    \1\ On September 8, 2011, at 76 FR 55774, EPA determined that
the Chattanooga TN-GA 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 Georgia portion of the
Chattanooga TN-GA 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 Catoosa and Walker
Counties in Georgia, located within the Chattanooga TN-GA Area, from
nonattainment to attainment for the 1997 Annual PM2.5 NAAQS.
    Second, EPA is proposing to approve Georgia's 1997 Annual
PM2.5 NAAQS maintenance plan for the Georgia portion of the
Chattanooga TN-GA 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 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 Georgia portion of the
Chattanooga TN-GA Area for transportation conformity purposes. EPA is
proposing to approve the 2025 MVEBs into the Georgia SIP that are
included as part of Georgia's maintenance plan for the 1997 Annual
PM2.5 NAAQS.
    Further, EPA proposes to make the determination that the
Chattanooga TN-GA Area is continuing to attain the 1997 Annual
PM2.5 NAAQS and that all other redesignation criteria have
been met for the Georgia portion of the Chattanooga TN-GA 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 Georgia portion of the Chattanooga TN-GA 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 Georgia's
September 14, 2012, SIP revision, which requests redesignation of the
Georgia portion of the Chattanooga TN-GA 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.

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 annual mean PM2.5 concentrations. In the same rulemaking,
EPA promulgated a 24-hour standard of 65 [mu]g/m\3\, based on a 3-year
average of the 98th percentile of 24-hour concentrations. On October
17, 2006, 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 Catoosa and Walker Counties in Georgia, in association with
counties in Alabama and Tennessee in the Chattanooga TN-GA 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 2006, designating
counties in the Chattanooga TN-GA Area as unclassifiable/attainment for
the 2006 24-hour PM2.5 NAAQS. See 74 FR 58688. That action
also clarified that the Georgia portion of the Chattanooga TN-GA 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, the
Georgia portion of the Chattanooga TN-GA 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
notice.
    The 3-year ambient air quality data for 2007-2009 indicated no
violations of the 1997 PM2.5 NAAQS for the Chattanooga TN-GA
Area. As a result, on September 14, 2012, Georgia requested
redesignation of the Georgia portion of the Chattanooga TN-GA 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 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 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 Georgia portion of the Chattanooga TN-GA 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
notice.

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 September 14, 2012, GA EPD requested the redesignation of the
Georgia portion of the Chattanooga TN-GA 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 Georgia 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
Georgia portion of the Chattanooga TN-GA Area. Additionally, EPA is
also approving the MVEBs for both NOX and direct
PM2.5 that were included in Georgia'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 Georgia portion of the
Chattanooga TN-GA Area to attainment for the 1997 Annual
PM2.5 NAAQS; and (2) approve into the Georgia SIP the 1997
Annual PM2.5 NAAQS maintenance plan, including the
associated MVEBs, for the for the Georgia portion of the Chattanooga
TN-GA Area. Further, EPA proposes to make the determination that the
Chattanooga TN-GA Area continues to attain the 1997 Annual
PM2.5 NAAQS and that all other redesignation criteria have
been met for the Georgia portion of the Chattanooga TN-GA 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 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 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 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 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 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 Area are below the 1997 Annual
PM2.5 NAAQS.

                           Table 1--Design Value Concentrations for the Chattanooga TN-GA 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
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Rossville--Maple St., Georgia..............  Walker County, Georgia.......    132950002       * 12.3         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         11.7         11.2         11.1         10.1
Soddy-Daisy High School, Tennessee.........  Hamilton County, Tennessee...    470651011         11.8         11.4         11.0         11.2          9.8
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* Values subject to data substitution (76 FR 15895).

    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
Georgia based its redesignation request (2007-2009) for the Chattanooga
TN-GA 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 Area. See 76 FR
31239 (May 31, 2011). EPA has reviewed more recent data which indicate
that the Chattanooga TN-GA 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, GA EPD has committed to continue
monitoring in this Area in accordance with 40 CFR part 58.

Criteria (5)--Georgia Has Met All Applicable Requirements Under Section
110 and Part D of the CAA; and Criteria (2)--Georgia Has a Fully
Approved SIP Under Section 110(k) for the Georgia Portion of the
Chattanooga TN-GA 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 Georgia has met all applicable SIP requirements
for the Georgia portion of the Chattanooga TN-GA Area under section 110
of the CAA (general SIP requirements) for purposes of redesignation.
Additionally, EPA proposes to find that the Georgia 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 Georgia Portion of the Chattanooga TN-GA 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 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 October 25, 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 65125. 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 Georgia
portion of the Chattanooga TN-GA Area.
    Title I, Part D, subpart 1 applicable SIP requirements. EPA
proposes to determine that the Georgia SIP meets the applicable SIP
requirements for the Georgia portion of the Chattanooga TN-GA 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); 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 notice. 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 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. 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
Area has monitored attainment of the 1997 Annual PM2.5
NAAQS. In addition, because the Chattanooga TN-GA 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 approval of a comprehensive,
accurate, and current inventory of actual emissions. On March 1, 2012,
EPA approved Georgia's 2002 base-year emissions inventory for the
Georgia portion of the Chattanooga TN-GA Area as part of the SIP
revision submitted by GA EPD to provide for attainment of the 1997
PM2.5 NAAQS in the Area. See 77 FR 12487.
    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.''
Georgia has demonstrated that the Georgia portion of the Chattanooga
TN-GA Area will be able to maintain the NAAQS without part D NSR in
effect, and therefore, Georgia need not have fully approved part D NSR
programs prior to approval of the redesignation request. Georgia's PSD
program will become effective in the Georgia portion of the Chattanooga
TN-GA 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
Georgia 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 Georgia portion of the
Chattanooga TN-GA Area has satisfied all applicable requirements for
purposes of redesignation under section 110 and part D of the CAA.
b. The Georgia Portion of the Chattanooga TN-GA Area Has a Fully
Approved Applicable SIP Under Section 110(k) of the CAA
    EPA has fully approved the applicable Georgia SIP for the Georgia
portion of the Chattanooga TN-GA Area for the 1997 Annual
PM2.5 nonattainment area 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, Georgia 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 Georgia portion of the Chattanooga TN-GA Area (e.g., 77 FR 65125
(October 25, 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 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 Georgia has demonstrated
that the observed air quality improvement in the Chattanooga TN-GA 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
sources and are composed of many different compounds. In the
Chattanooga TN-GA 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 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 is being 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. 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 D.C. Circuit granted EPA's motion. EME
Homer City Generation, L.P. v. EPA, Case No. 11-1302, Document No.
1518738.
    EPA approved a modification to Georgia's SIP on October 9, 2007,
that addressed the requirements of CAIR for the purpose of reducing
SO2 and NOX emissions (see 72 FR 57202), and
Georgia's SIP redesignation request lists CAIR/CSAPR as a control
measure. CAIR was in place and getting emission reductions when the
Chattanooga TN-GA 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 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. Therefore, to the extent that
these transport rules impact attainment of the 1997 Annual
PM2.5 NAAQS in the Chattanooga TN-GA Area, any emission
reductions associated with CAIR that helped the Chattanooga TN-GA 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
Area as receptors.
---------------------------------------------------------------------------

    State-only Measures. In its redesignation request, GA EPD

identified Georgia rules 391-3-1-.02(2)(sss) (``Multipollutant Rule'')
and 391-3-1-.02(2)(uuu) (``SO2 Emissions from Electric Steam
Utility Steam Generating Units'') as two state-only measures that
improve PM2.5 air quality in the Chattanooga TN-GA Area.
Rule (sss) requires flue gas desulfurization (FGD) and selective
catalytic reduction (SCR) on the majority of the coal-fired EGUs in
Georgia, and Rule (uuu) requires a 95 percent reduction in
SO2 emissions from the majority of the coal-fired EGUs in
Georgia. The implementation dates for Rules (sss) and (uuu) vary by
EGU, starting on December 31, 2008, for Rule (sss) and January 1, 2010
for Rule (uuu). By the end of 2009, FGDs mandated by Rule (sss) were
operating at Plant Hammond (4 of 4 subject units), Plant Bowen (2 of 4
subject units), and Plant Wansley (1 of 2 subject units). Although GA
EPD discusses the emissions reductions resulting from Rules (sss) and
(uuu) in its redesignation request, these rules were not necessary for
attainment of the 1997 Annual PM2.5 NAAQS for the reasons
discussed below. EPA has therefore not relied on these state-only rules
as a basis for proposing approval of the redesignation request and
associated maintenance plan.
    GA EPD analyzed the sensitivity of PM2.5 concentrations
at the four PM2.5 monitors in the Chattanooga TN-GA Area to
reductions in SO2 emissions due to the installation and
operation of FGD by the end of 2009 pursuant to Rule (sss) at the EGUs
identified above.\7\ The analysis was based on modeling conducted by
the Visibility Improvement State and Tribal Association of the
Southeast (VISTAS) using emissions inventories for 2002 and 2009 and
CMAQ version 4.5 with the CB-IV chemical mechanism.
---------------------------------------------------------------------------

    \7\ GA EPD, Sensitivity of Annual PM2.5 in
Chattanooga to SO2 Emission Reductions Resulting from
Georgia's Multipollutant Rule [391-3-1-.02(2)(sss)] (attached to an
October 28, 2014 email from James Boylan, GA EPD, to Lynorae
Benjamin, EPA Region 4). The email and attachments are included in
the docket for this action.
---------------------------------------------------------------------------

    Based on the sensitivity analysis, GA EPD concluded that the
emissions reductions from Rule (sss) were not necessary for attainment
of the 1997 Annual PM2.5 NAAQS.\8\ GA EPD estimated that the
Rule (sss) controls in place by the end of 2009 impacted the 2007-09
Annual PM2.5 design value by approximately 0.5 [mu]g/m\3\.
Therefore, removing the effect of these controls would result in a
2007-09 design value of 13.4 [mu]g/m\3\ (12.9 [mu]g/m\3\ plus 0.5
[mu]g/m\3\), well below the 15.0 [mu]g/m\3\ standard.\9\ Furthermore,
Rule (uuu) was not necessary for attainment of the 1997 Annual
PM2.5 NAAQS in 2007-09 because it was not implemented until
January 1, 2010. All monitors in the Chattanooga Area have registered
annual PM2.5 readings below 15 [mu]g/m\3\ since 2006, and
the 2006-08 design value for the Area was below the 1997 Annual
PM2.5 NAAQS.
---------------------------------------------------------------------------

    \8\ Because Rules (sss) and (uuu) were unnecessary for
attainment in 2007-09 and because the permanent and enforceable
measures necessary for attainment are expected to remain in place
during the first maintenance period, these rules are also
unnecessary for maintenance of the standard through 2025.
    \9\ In its redesignation request and October 28, 2014 technical
analysis, Georgia identified a 2007-09 design value of 12.7 [mu]g/
m\3\. The correct design value is 12.9 [mu]g/m\3\ as identified in
Table 1 of this Federal Register notice.
---------------------------------------------------------------------------

Criteria (4)--The Georgia Portion of the Chattanooga TN-GA 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
Georgia portion of the Chattanooga TN-GA Area to attainment for the
1997 Annual PM2.5 NAAQS, GA EPD 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, GA EPD 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 finds that GA EPD's
maintenance plan includes all the necessary components and is thus
proposing to approve it as a revision to the Georgia SIP.
b. CAA 175 Maintenance Plan Requirements
1. Attainment Emissions Inventory
    The Chattanooga TN-GA Area attained the 1997 Annual
PM2.5 NAAQS based on monitoring data for the 3-year period
from 2007-2009. GA EPD 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. GA EPD began development of the attainment
inventory by first generating a baseline emissions inventory for the
Georgia portion of the Chattanooga TN-GA 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 2017
and 2025. In addition, emissions have been calculated by interpolation
for the years 2014 and 2020. 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 2007
inventory, with the exception of on-road emissions, was prepared for
Georgia by the contractor for the Southeastern Modeling, Analysis, and
Planning (SEMAP) project. Under the SEMAP project, emissions estimates
are reported by county and source classification code. The SEMAP
emissions inventories were developed using data from a number of
sources, including state and local agencies and EPA's National
Emissions Inventory (NEI). The Georgia Department of Transportation
developed the 2007 inventory of on-road mobile emissions. The 2007
SO2, NOX, and PM2.5 emissions for the
Georgia portion of the Chattanooga TN-GA 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 September 14, 2012, final submittal includes a maintenance plan
for the Georgia portion of the Chattanooga TN-GA 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 and
NOX will remain below 2007 emission levels and that a slight
increase in direct PM2.5 emissions will not interfere with
maintenance.
    (ii) Uses 2007 as the attainment year and includes future emission
inventory projections for 2017 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 Georgia
portion of the Chattanooga TN-GA Area.

  Table 2--Actual (2007) and Projected Point Source Emissions for the Georgia Portion of the Chattanooga TN-GA
                                                      Area
                                                     [Tons]
----------------------------------------------------------------------------------------------------------------
            Pollutant                  2007            2014            2017            2020            2025
----------------------------------------------------------------------------------------------------------------
SO2.............................             280             285             287             290             295
NOX.............................              48              49              49              50              52
PM2.5...........................               0               0               0               0               0
----------------------------------------------------------------------------------------------------------------

Table 3--Actual (2007) and Projected Non-Point Source Emissions for the Georgia Portion of the Chattanooga TN-GA
                                                      Area
                                                     [Tons]
----------------------------------------------------------------------------------------------------------------
            Pollutant                  2007            2014            2017            2020            2025
----------------------------------------------------------------------------------------------------------------
SO2.............................              77              81              82              84              87
NOX.............................             359             397             414             430             456
PM2.5...........................           1,548           1,729           1,807           1,878           1,998
----------------------------------------------------------------------------------------------------------------

Table 4--Actual (2007) and Projected On-Road Mobile Sources Emissions for the Georgia Portion of the Chattanooga
                                                   TN-GA Area
                                                     [Tons]
----------------------------------------------------------------------------------------------------------------
            Pollutant                  2007            2014            2017            2020            2025
----------------------------------------------------------------------------------------------------------------
SO2.............................              20              17              15              14              11
NOX.............................           4,442           3,112           2,542           1,972           1,022
PM2.5...........................             134              96              80              63              36
----------------------------------------------------------------------------------------------------------------

Table 5--Actual (2007) and Projected Non-Road Mobile Source Emissions for the Georgia Portion of the Chattanooga
                                                   TN-GA Area
                                                     [Tons]
----------------------------------------------------------------------------------------------------------------
            Pollutant                  2007            2014            2017            2020            2025
----------------------------------------------------------------------------------------------------------------
SO2.............................              27             8.8             0.8             0.8             0.9
NOX.............................             633             450             372             336             277
PM2.5...........................              51              38              32              28              22
----------------------------------------------------------------------------------------------------------------

 Table 6--Actual (2007) and Projected Emissions for All Sectors for the Georgia Portion of the Chattanooga TN-GA
                                                      Area
                                                     [Tons]
----------------------------------------------------------------------------------------------------------------
            Pollutant                  2007            2014            2017            2020            2025
----------------------------------------------------------------------------------------------------------------
SO2.............................             404             391             385             389             394
NOX.............................           5,482           4,009           3,377           2,788           1,806
PM2.5...........................           1,733           1,863           1,918           1,970           2,056
----------------------------------------------------------------------------------------------------------------

    As reflected in Table 6, future emissions of NOX and
SO2 are expected to be below the ``attainment level''
emissions in 2007, while direct PM2.5 emissions are expected
to increase slightly. In situations where local emissions are the
primary contributor to nonattainment, such as the Chattanooga TN-GA
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 finds that the overall emission
projections illustrate that the Chattanooga TN-GA Area is expected to
continue to attain the 1997 PM2.5 NAAQS through 2025.\10\
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    \10\ Based on a limited review of data and emissions projections
available to EPA from the Alabama and Tennessee portions of the
Chattanooga TN-GA Area, EPA does not at this time 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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    Emissions of SO2 and NOX are projected to
decline by 2.5 percent and 67.1 percent, respectively, from 2007 to
2025. During the same period, emissions of PM2.5 are
projected to increase slightly, by 18.6 percent. EPA does not believe
that this 18.6 percent increase in PM2.5 emissions will
threaten maintenance in the Area because even with this projected
increase, as explained below, the overall projected design value
remains well below the standard.
    Because the relationship between pollutant emissions and ambient
air quality is different for each of the three pollutants, the changes
in emissions for each pollutant must be weighted according to the air
quality impact of each pollutant to obtain an appropriate indicator of
the overall impact. For this purpose, GA EPD examined speciation data
available from the EPA Air Explorer Web site for 2007-2009 for
Chattanooga monitor ID 47-065-4002. The 3-year average of this data
suggests that ambient PM2.5 in Chattanooga consists of
approximately 48.1 percent sulfate; 2.4 percent nitrate; 40.6 percent
organic particulate matter (which consists of directly-emitted primary
organic matter and atmospherically formed secondary organic aerosol); 5
percent miscellaneous inorganic particulate matter; and 3.9 percent
other types of particulate matter. Therefore, using a conservative
assumption that all of the organic particulate matter is primary
organic matter, the direct PM2.5 species make up 45.6
percent of the total ambient PM2.5.
    GA EPD used a conservative approach that assumes the full ambient
concentration of organic particulate matter plus miscellaneous
inorganic particulate matter will vary in accordance with changes in
total nonattainment area emissions of direct PM2.5. This
analysis thus assumes that the direct PM2.5 component of
ambient PM2.5 will increase by the 18.6 percent projected
increase in direct PM2.5 emissions for the Georgia portion
of the Chattanooga TN-GA Area. The baseline concentration is
conservatively assumed to be 15.0 [mu]g/m\3\, and direct
PM2.5 is estimated to contribute 45.6 percent, or 6.84
[mu]g/m\3\, of that value. Thus, an 18.6 percent increase in the 6.84
[mu]g/m\3\ of the direct PM2.5 component would suggest a
resulting 1.27 [mu]g/m\3\ increase in the ambient PM2.5
concentration.
    EPA believes that the projected increase in direct PM2.5
emissions will be overcompensated by a significant projected decrease
in sulfate and nitrate emissions. As shown in Table 1, above, the
emissions reductions that have already occurred have brought the
PM2.5 design value for the Chattanooga TN-GA Area down to
11.7 [mu]g/m\3\, based on 2008-2010 data. Therefore, the 1.27 [mu]g/
m\3\ increase in the components associated with direct PM2.5
would not be expected to yield concentrations above the standard. The
emissions reductions in SO2 and NOX projected by
Georgia are due, in part, to the federal mobile source rules described
in section V of this notice, and EPA believes that the State's
projections are reasonable. In EPA's Regulatory Impact Analysis (RIA)
entitled ``Control of Air Pollution from New Motor Vehicles: Tier 2
Motor Vehicle Emissions Standards and Gasoline Sulfur Control
Requirements released December 1999,'' \11\ EPA projected that
implementation of the Tier 2/Low Sulfur rule would immediately and
substantially reduce SOX emissions from cars and trucks once
its fuel sulfur provisions began to take effect in 2004. EPA estimated
that 90 percent of light-duty SOX emissions would be reduced
when fuel with 30 ppm of sulfur was introduced into the market in 2006.
EPA noted that SOX emission reductions would also occur from
heavy-duty gasoline vehicles and motorcycles due to the reduced sulfur
content in fuel. In the RIA, EPA estimated that the reductions would be
approximately 10,000 tpy in 2005, growing to 16,000 tons by 2030. In
addition, the Agency anticipated that emissions from all gasoline-
powered nonroad equipment would be reduced due to reduced sulfur
content in fuel, by approximately 25,000 tpy between 2005 and 2020. EPA
expects additional reductions in SO2 and NOX
emissions from mobile sources as a result of the Tier 3 vehicle
standards that will take effect in 2017 and reduce both tailpipe and
evaporative emissions from passenger cars, light-duty trucks, medium-
duty passenger vehicles, and some heavy-duty vehicles. See 79 FR 23414
(April 28, 2014). Georgia's projections of mobile source emissions
through 2025 did not include the emissions reductions expected from the
implementation of the Tier 3 standards, and therefore, likely
underestimate the mobile source emissions reductions in NOX
and SO2 expected from 2017 through 2025 in the Georgia
portion of the Chattanooga TN-GA Area.
---------------------------------------------------------------------------

    \11\ EPA's RIA entitled ``Control of Air Pollution from New
Motor Vehicles: Tier 2 Motor Vehicle Emissions Standards and
Gasoline Sulfur Control Requirements released December 1999 can be
found under EPA document number, EPA420-R-99-023.
---------------------------------------------------------------------------

    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
agrees that Georgia's projected emissions demonstrate that the
Chattanooga TN-GA Area will continue to attain for the duration of the
maintenance plan.
3. Monitoring Network
    There is currently one monitor measuring ambient PM2.5
in the Georgia portion of the Chattanooga TN-GA Area. GA EPD has
committed to continue operation of the monitor in the Georgia portion
of the Chattanooga TN-GA Area in compliance with 40 CFR part 58 and has
thus addressed the requirement for monitoring. EPA approved Georgia's
2013 monitoring plan on November 25, 2013.
4. Verification of Continued Attainment
    GA EPD has the legal authority to enforce and implement the
requirements of the Georgia portion of the Chattanooga TN-GA 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.
    GA EPD will track the progress of the maintenance plan by
performing future reviews of triennial emission inventories for the
Georgia portion of the Chattanooga TN-GA Area as required in the Air
Emissions Reporting Rule (AERR) and Consolidated Emissions Reporting
Rule (CERR). For these periodic inventories, GA EPD 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 GA EPD will re-
project emissions for the Georgia portion of the Chattanooga TN-GA
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 GA EPD. A state should
also identify specific indicators to be used to determine when the
contingency measures need to be implemented. The maintenance plan must
include a requirement that a state will implement all measures with
respect to control of the pollutant that were contained in the SIP
before redesignation of the area to attainment in accordance with
section 175A(d).
    The contingency plan included in the submittal includes a
triggering mechanism to determine when contingency measures are needed
and a process of developing and implementing appropriate control
measures. GA EPD will use actual ambient monitoring data to determine
whether a trigger event has occurred and when contingency measures
should be implemented.
    Georgia has identified a Tier 1 trigger as occurring when any of
the following conditions occurs, as described in the State's submittal
for the Georgia portion of the Chattanooga TN-GA Area:
     The previous calendar year's annual average
PM2.5 concentration exceeds the standard by 1.5 [micro]g/
m\3\ or more;
     The annual mean PM2.5 concentration in each of
the previous two consecutive calendar years exceeds the NAAQS by 0.5
[micro]g/m\3\ or more;
     The total maintenance area SO2 emissions in the
most recent NEI exceeds the corresponding attainment-year inventory by
more than 30.0 percent;
     The total maintenance area PM2.5 emissions in
the most recent NEI exceed the corresponding attainment-year inventory
by more than 30.0 percent.
    GA EPD will evaluate a Tier I condition, if it occurs, as
expeditiously as practicable to determine the causes of the ambient
PM2.5 or emissions inventory increase and to determine if a
Tier II condition is likely to occur. A Tier II trigger will be
activated when any violation of the Annual PM2.5 NAAQS at
any federal reference method (FRM) monitor in the Georgia portion of
the Chattanooga TN-GA maintenance area is recorded, based on quality-
assured monitoring data. In this event, GA EPD will conduct a
comprehensive study to determine the cause of the ambient
PM2.5 increase and to determine if the increase is likely to
continue and will implement any required measures as expeditiously as
practicable, taking into consideration the ease of implementation and
the technical and economic feasibility of selected measures.
    The comprehensive study will be completed and submitted to EPA as
expeditiously as practical but no later than nine months after the Tier
I or Tier II trigger is activated, and the appropriate corrective
measures will be adopted and implemented within 18 to 24 months after
the trigger occurs. If the study determines that additional measures
are required, the State will adopt rules no later than 18 months
following the date that the trigger is activated.\12\ The comprehensive
measures will be selected from the following types of measures or from
any other measure deemed appropriate and effective at the time the
selection is made by GA EPD:
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    \12\ In a September 23, 2013, letter to EPA, the State
reaffirmed its commitment to address and correct any violation of
the 1997 Annual PM2.5 NAAQS as expeditiously as
practicable and no later than 24 months from the trigger activation.
---------------------------------------------------------------------------

     RACM for sources of SO2 and PM2.5;
     Reasonably Available Control Technologies (RACT) for point
sources of SO2 and PM2.5;
     Expansion of RACM/RACT to areas of transport within the
State;
     Mobile source measures; and
     Additional SO2 and/or PM2.5
reduction measures yet to be identified.
    In addition to the triggers indicated above, Georgia will monitor
regional emissions through the CERR and AERR and compare them to the
projected inventories and the attainment year inventory. In the
September 14, 2012, submittal, the State acknowledges that the
contingency plan requires the implementation of all measures contained
in the SIP for the Area prior to redesignation. The State also notes
that these measures are currently in effect and may be evaluated by the
State to determine if they are adequate or up-to-date.
    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 GA EPD for the Georgia portion of the Chattanooga
TN-GA 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 Georgia portion of the Chattanooga TN-GA 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 Georgia portion of the Chattanooga TN-GA Area redesignation request
and disregards the provisions of its 1997 PM2.5
Implementation Rule recently remanded by the Court, the State's request
for redesignation of Georgia portion of the Chattanooga TN-GA Area
still qualifies for approval. EPA's discussion takes into account the
effect of the Court's ruling on the maintenance plan for the Georgia
portion of the Chattanooga TN-GA 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 Georgia's redesignation request for the Georgia portion of
the Chattanooga TN-GA 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 Georgia portion of the Chattanooga TN-GA 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'').\13\ In this case, at the time that Georgia submitted its
redesignation request on September 14, 2012, requirements under subpart
4 were not due, and indeed, were not yet known to apply.
---------------------------------------------------------------------------

    \13\ 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 Georgia 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.
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.
    In the context of this redesignation, the timing and nature of the
Court's January 4, 2013, decision in NRDC v. EPA compound the
consequences of imposing requirements that come due after the
redesignation request is submitted. The State submitted its
redesignation request on September 14, 2012, but the Court did not
issue its decision remanding EPA's 1997 PM2.5 implementation
rule concerning the applicability of the provisions of subpart 4 until
January 2013.
    To require the State's fully-completed and pending redesignation
request to comply now with requirements of subpart 4 that the Court
announced only in January 2013 would be to give retroactive effect to
such requirements when the State had no notice that it was required to
meet them. The D.C. Circuit recognized the inequity of this type of
retroactive impact in Sierra Club v. Whitman, 285 F.3d 63 (D.C. Cir.
2002),\14\

where it upheld the District Court's ruling refusing to make
retroactive EPA's determination that the St. Louis area did not meet
its attainment deadline. In that case, petitioners urged the Court to
make EPA's nonattainment determination effective as of the date that
the statute required, rather than the later date on which EPA actually
made the determination. The Court rejected this view, stating that
applying it ``would likely impose large costs on States, which would
face fines and suits for not implementing air pollution prevention
plans . . . even though they were not on notice at the time.'' Id. at
68. Similarly, it would be unreasonable to penalize the State of
Georgia by rejecting its redesignation request for an area that is
already attaining the 1997 PM2.5 standard and that met all
applicable requirements known to be in effect at the time of the
request. For EPA now to reject the redesignation request solely because
the state did not expressly address subpart 4 requirements of which it
had no notice would inflict the same unfairness condemned by the Court
in Sierra Club v. Whitman.
---------------------------------------------------------------------------

    \14\ Sierra Club v. Whitman was discussed and distinguished in a
recent D.C. Circuit decision that addressed retroactivity in a quite
different context, where, unlike the situation here, EPA sought to
give its regulations retroactive effect. National Petrochemical and
Refiners Ass'n v. EPA. 630 F.3d 145, 163 (D.C. Cir. 2010), rehearing
denied 643 F.3d 958 (D.C. Cir. 2011), cert denied 132 S. Ct. 571
(2011).
---------------------------------------------------------------------------

d. Subpart 4 Requirements and the Georgia Portion of the Chattanooga
TN-GA 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
Georgia portion of the Chattanooga TN-GA Area still qualifies for
redesignation to attainment. As explained below, EPA believes that the
redesignation request for the Georgia 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 Georgia 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 Georgia portion of the
Chattanooga TN-GA 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 \15\ 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.\16\ 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 PM10
requirements.'' See 57 FR 13538. The subpart 1 requirements include,
among other things, provisions for attainment demonstrations, RACM RFP,
emissions inventories, and contingency measures.
---------------------------------------------------------------------------

    \15\ PM10 refers to particles nominally 10
micrometers in diameter or smaller.
    \16\ See ``State Implementation Plans; General Preamble for the
Implementation of Title I of the Clear Air Act Amendments of 1990,''
57 FR 13498 (April 16, 1992) (the ``General Preamble'').
---------------------------------------------------------------------------

    For the purposes of this redesignation, in order to identify any
additional requirements which would apply under subpart 4, EPA is
considering the Georgia portion of the Chattanooga TN-GA 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.\17\ 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, October 23, 2001); and Grand
Rapids, Michigan (61 FR 31834-31837, June 21, 1996).
---------------------------------------------------------------------------

    \17\ 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,\18\ 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.
---------------------------------------------------------------------------

    \18\ 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 \19\ 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.
---------------------------------------------------------------------------

    \19\ 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 notice, 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. Sec.  7513a(e)
[section 189(e)]. Id. at 21, n.7.

    For a number of reasons, EPA believes that its proposed
redesignation of the Georgia portion of the Chattanooga TN-GA 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 Area, EPA believes that doing so is consistent with proposing
redesignation of the area for the PM2.5 standard. The
Chattanooga TN-GA 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.\20\ 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, we 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, we do not believe
that any additional controls of ammonia and VOC are required in the
context of this redesignation.
---------------------------------------------------------------------------

    \20\ 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 findings
that: (1) the Georgia portion of the Chattanooga TN-GA 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.\21\ 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 Area. See 57 FR 13539.
---------------------------------------------------------------------------

    \21\ The Chattanooga TN-GA 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 we regard 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.\22\ Courts have upheld this approach to the requirements of
subpart 4 for PM10.\23\ EPA believes that application of
this approach to PM2.5 precursors under subpart 4 is
reasonable. Because the Chattanooga TN-GA 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 Georgia's request for redesignation of the Georgia
portion of the Chattanooga TN-GA Area. In the context of a
redesignation, Georgia has shown that the Chattanooga TN-GA 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 Georgia portion of the Chattanooga TN-GA Area to
attainment for the 1997 Annual PM2.5 NAAQS at this time. In
sum, even if Georgia were required to address precursors for Georgia
portion of the Chattanooga TN-GA 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).
---------------------------------------------------------------------------

    \22\ 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).
    \23\ 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 Georgia portion of the
Chattanooga TN-GA 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 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 Georgia and
supporting information, EPA believes that the maintenance plan for the
Georgia portion of the Chattanooga TN-GA 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,
as shown in table 7 below, VOC emissions are projected to decrease by
over 2,000 tpy by 2020, and ammonia emissions are projected to increase
only slightly. 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.

 Table 7--Comparison of 2007 and 2020 VOC and Ammonia Emission Totals by
  Source Sector (tpy) for the Georgia Portion of the Chattanooga TN-GA
                                Area \24\
------------------------------------------------------------------------
                                          VOC               Ammonia
                                 ---------------------------------------
          Source sector                         Net                 Net
                                  2007  2020  change  2007  2020  change
------------------------------------------------------------------------
Nonpoint........................  2,26  2,24  -17.62  2,03  2,35  317.48
                                  5.68  8.06          5.25  2.73
Nonroad.........................  634.  357.  -277.1  0.5   0.63  0.13
                                   32    18      4
Onroad..........................  2,62  859.  -1,763  80.4  42.0  -38.40
                                  2.3    26    .04      5     5
Point...........................  45.6  45.6  -0.04     0     0      0
                                    6     2
                                 ---------------------------------------
    Total.......................  5,56  3,51  -2,057  2,11  2,39  279.21
                                  7.96  0.12   .84    6.20  5.41
------------------------------------------------------------------------

---------------------------------------------------------------------------

    \24\ These emissions estimates were taken from the emissions
inventories developed for the RIA for the 2012 PM2.5
NAAQS.
---------------------------------------------------------------------------

    Georgia's maintenance plan shows that emissions of SO2
and NOX are projected to decrease over the maintenance
period in the Georgia portion of the Chattanooga TN-GA Area by 10 tpy
and 3,676 tpy, respectively, while direct PM2.5 emissions
are projected to increase by 323 tpy. See Table 6, above. In addition,
emissions inventories used

in the RIA for the 2012 PM2.5 NAAQS \25\ show that VOC
emissions are projected to decrease by 2,057.84 tpy and that ammonia
emissions are projected to increase by 279.21 tpy between 2007 and
2020. Although ammonia emissions are projected to increase slightly
between 2007 and 2020, the decrease in emissions of other precursors in
comparison will keep the Area well below the standard. See Table 6 and
7, above. 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 Area
is already attaining the 1997 Annual PM2.5 NAAQS even with
the current level of emissions from sources in the Area, the overall
trend of emissions inventories would be consistent with continued
attainment. Indeed, projected emissions reductions for the precursors
that the State is addressing for purposes of the 1997 Annual
PM2.5 NAAQS indicate that the Area should continue to attain
the NAAQS following the precursor control strategy that the State has
already elected to pursue. 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 will cause monitored
PM2.5 levels to violate the 1997 Annual PM2.5
standard during the maintenance period.
---------------------------------------------------------------------------

    \25\ The RIA for the 2012 PM2.5 NAAQS standard can be
found on EPA's Web site at http://www.epa.gov/ttn/ecas/regdata/RIAs/finalria.pdf.
---------------------------------------------------------------------------

    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 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 [micro]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 Georgia portion of the Chattanooga TN-GA 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 notice, EPA continues to propose approval of the
State's maintenance plan and its request to redesignate the Georgia
portion of the Chattanooga TN-GA Area to attainment for the 1997 Annual
PM2.5 NAAQS.

VII. What is EPA's analysis of Georgia's proposed NOX and
PM2.5 MVEBs for the Georgia portion of the Chattanooga TN-GA
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 Georgia portion of the Chattanooga TN-GA Area, Georgia has elected
to develop MVEBs for NOX and PM2.5 for the
Georgia portion of the Chattanooga TN-GA Area. Georgia 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 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 Georgia
portion of the Chattanooga TN-GA Area are defined in Table 8 below.

    Table 8--PM2.5 and NOX MVEBs (tpy) for the Georgia Portion of the
                         Chattanooga TN-GA Area
------------------------------------------------------------------------
                                                      PM2.5       NOX
------------------------------------------------------------------------
2025 Mobile Emissions............................       36       1,021.8
2025 Safety Margin Allocated.....................        8.2       364.6
                                                  ----------------------
  2025 Total Mobile Budget.......................       44.2     1,386.5
------------------------------------------------------------------------

    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, GA EPD 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 36 tpy and
1,021.8 tpy, respectively. On-road emissions of SO2

are considered de-minimus; therefore, no budget for SO2 is
required.\26\
---------------------------------------------------------------------------

    \26\ 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 22.8 percent above the projected 2025 on-road
emissions. In a worst-case scenario, the needed annual safety margin
for the PM2.5 MVEB would be 8.2 tpy resulting in an overall
MVEB of 44.2 tpy. The worst-case daily motor vehicle emissions
projection for NOX is 35.7 percent above the projected 2025
on-road emissions. In a worst-case scenario, the required annual safety
margin for the NOX MVEB would be 364.6 tpy resulting in an
overall MVEB of 1,386.5 tpy.
    Through this rulemaking, EPA is proposing to approve the MVEBs for
NOX and PM2.5 for 2025 for the Georgia
portion of the Chattanooga TN-GA 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 Georgia
portion of the Chattanooga TN-GA 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
Georgia portion of the Chattanooga TN-GA 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, Georgia's maintenance plan submission
includes NOX and PM2.5 MVEBs for the Georgia
portion of the Chattanooga TN-GA 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 March 4, 2013,
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 Georgia portion of the Chattanooga TN-GA Area closed
on April 3, 2013. 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 Georgia portion of the Chattanooga TN-GA Area for
transportation conformity purposes in the near future by completing the
adequacy process that was started on March 4, 2013. After EPA finds the
2025 MVEBs adequate or takes final action to approve them into the
Georgia SIP, 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 Georgia Portion of the
Chattanooga TN-GA Area

    On May 31, 2011, EPA determined that the Chattanooga TN-GA Area was
attaining the 1997 PM2.5 NAAQS. See 76 FR 31239. 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 Area continues to attain the 1997 Annual
PM2.5 NAAQS. EPA is also proposing to determine that the
Georgia portion of the Chattanooga TN-GA Area has met the criteria
under CAA section 107(d)(3)(E) for redesignation from nonattainment to
attainment for the 1997 Annual PM2.5 NAAQS. On this basis,