[Federal Register Volume 77, Number 134 (Thursday, July 12, 2012)]
[Proposed Rules]
[Pages 41132-41146]
[FR Doc No: 2012-16959]

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Parts 52 and 81

[EPA-R04-OAR-2011-0084; FRL-9698-8]

Air Quality Implementation Plans; Alabama; Attainment Plan for
the Alabama Portion of the Chattanooga 1997 Annual PM2.5
Nonattainment Area

AGENCY: Environmental Protection Agency (EPA or Agency).

ACTION: Proposed rule.

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SUMMARY: EPA is proposing to approve a state implementation plan (SIP)
revision submitted by the State of Alabama, through the Alabama
Department of Environmental Management (ADEM) to EPA on October 7,
2009, for the purpose of providing for attainment of the 1997 fine
particulate matter (PM2.5) national ambient air quality
standards (NAAQS) in the Alabama portion of the tri-state Chattanooga
PM2.5 nonattainment area (hereafter referred to as the
``Chattanooga Area'' or ``Area''). The Chattanooga Area is comprised of

Catoosa and Walker Counties in Georgia; Hamilton County in Tennessee;
and a portion of Jackson County in Alabama. The Alabama SIP revision
(hereafter referred to as the ``attainment plan'') pertains only to the
Alabama portion of the Chattanooga Area (hereafter referred to as
``Jackson County''). EPA is now proposing to approve Alabama's October
7, 2009, SIP revision regarding reasonably available control technology
(RACT) and reasonably available control measures (RACM); reasonable
further progress (RFP); contingency measures; and, for transportation
conformity purposes, an insignificance determination for
PM2.5 and nitrogen oxides (NOx) for the mobile source
contribution to ambient PM2.5 levels for the Alabama portion
of the Chattanooga Area. This action is being taken in accordance with
the Clean Air Act (CAA or Act) and the ``Clean Air Fine Particle
Implementation Rule,'' hereafter referred to as the ``PM2.5
Implementation Rule,'' issued by EPA on April 25, 2007. The States of
Georgia and Tennessee have provided separate SIP revisions with
attainment plans for their portions for the Chattanooga Area. EPA is
not addressing those SIP revisions in this proposed rulemaking.

DATES: Written comments must be received on or before August 13, 2012.

ADDRESSES: Submit your comments, identified by Docket ID Number EPA-
R04-OAR-2011-0084 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-2011-0084, 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 to 4:30, excluding federal holidays.
    Instructions: Direct your comments to Docket ID No. EPA-R04-OAR-
2011-0084. EPA's 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 to 4:30, excluding
federal holidays.

FOR FURTHER INFORMATION CONTACT: Joel Huey or Richard Wong 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. Joel Huey may be reached by phone at<PHONE_NUMBER>, or via
electronic mail at<EMAIL_ADDRESS>Richard Wong may be reached by
phone at<PHONE_NUMBER>, or via electronic mail at
<EMAIL_ADDRESS>
SUPPLEMENTARY INFORMATION:

Table of Contents

I. What action is EPA proposing to take?
II. What is the background for EPA's proposed action?
    A. Designation History
     B. Clean Air Fine Particle Implementation Rule
     C. Stay of the Transport Rule
     D. Attaining Data Determination and Finding of Attainment
III. What is included in Alabama's attainment plan submittal for
Jackson County?
IV. What is EPA's analysis of Alabama's attainment plan submittal
for Jackson County?
     A. Attainment Demonstration
     1. Pollutants Addressed
     2. Emissions Inventory Requirements
     3. Modeling
     4. Reasonably Available Control Measures/Reasonably Available
Control Technology (RACM/RACT)
     5. Reasonable Further Progress
     6. Contingency Measures
     7. Attainment Date
     B. Insignificance Determination for the Mobile Source
Contribution to PM2.5 and NOX Emissions
V. Proposed Action
VI. Statutory and Executive Order Reviews

I. What action is EPA proposing to take?

    EPA is proposing to approve Alabama's SIP revision for the Alabama
portion of the Chattanooga Area, as submitted through the ADEM to EPA
on October 7, 2009, for the purpose of demonstrating attainment of the
1997 Annual PM2.5 NAAQS. Alabama's PM2.5
attainment plan for Jackson County includes an analysis of RACM/RACT,
an RFP plan, contingency measures, and an insignificance determination
for mobile direct PM2.5 and NOX emissions for
transportation conformity purposes. EPA previously approved the base
year emissions inventory for the Alabama portion of the Chattanooga
Area on February 8, 2012 (77 FR 6469).
    EPA has determined that Alabama's PM2.5 attainment plan
for the 1997 Annual PM2.5 NAAQS for Jackson County meets the
applicable requirements of the CAA and the PM2.5

Implementation Rule. Thus, EPA is proposing to approve Alabama's
attainment plan for Jackson County, including the insignificance
determination for direct PM2.5 and NOX for
Alabama's mobile source contribution to ambient PM2.5 levels
in the Chattanooga Area. EPA's analysis for this proposed action is
discussed in Section IV of this proposed rulemaking.

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

A. Designation History

    On July 18, 1997 (62 FR 38652), EPA established the 1997
PM2.5 NAAQS as an annual standard of 15.0 micrograms per
cubic meter ([micro]g/m\3\), based on a 3-year average of annual mean
PM2.5 concentrations, and a 24-hour (or daily) standard of
65 [micro]g/m\3\, based on a 3-year average of the 98th percentile of
24-hour concentrations. EPA established the NAAQS based on significant
evidence and numerous health studies demonstrating that serious health
effects are associated with exposures to PM2.5 emissions.
    Following promulgation of a new or revised NAAQS, EPA is required
by the CAA to designate areas throughout the United States as attaining
or not attaining the NAAQS; this designation process is described in
section 107(d)(1) of the CAA. EPA and state air quality agencies
initiated the monitoring process for the 1997 PM2.5 NAAQS in
1999 and established a complete set of air quality monitors by January
2001. On January 5, 2005, EPA promulgated initial air quality
designations for the 1997 PM2.5 NAAQS (70 FR 944), which
became effective on April 5, 2005, based on air quality monitoring data
for calendar years 2001-2003.
    On April 14, 2005, EPA promulgated a supplemental rule amending the
Agency's initial designations (70 FR 19844) but retaining the original
effective date of April 5, 2005. As a result of that supplemental rule,
PM2.5 nonattainment designations were in effect for 39
areas, comprising 208 counties within 20 states (and the District of
Columbia) nationwide, with a combined population of about 88 million.
The Alabama portion of the tri-state (Tennessee, Georgia and Alabama)
Chattanooga Area, which is the subject of this proposed rulemaking, is
included in the list of areas designated nonattainment for the 1997
PM2.5 NAAQS. As mentioned above, the Alabama portion of the
Chattanooga Area consists of a portion of Jackson County in Alabama.
    On October 17, 2006, EPA strengthened the 24-hour PM2.5
NAAQS to 35 [micro]g/m\3\ and retained the level of the Annual
PM2.5 NAAQS at 15.0 [micro]g/m\3\. See 71 FR 61144. On
November 13, 2009, EPA designated areas as attainment/unclassifiable,
unclassifiable or nonattainment with respect to the 2006 24-Hour
PM2.5 NAAQS. See 74 FR 58688. Of relevance to the proposed
rulemaking herein, EPA's November 2009 designation action clarified the
designations for the 1997 PM2.5 NAAQS by relabeling the
existing designation tables to specifically identify designations made
for the 1997 Annual PM2.5 NAAQS and those made for the 1997
24-hour PM2.5 NAAQS (i.e., 65 [micro]g/m\3\). The Alabama
portion of the Chattanooga Area is only designated nonattainment for
the 1997 Annual PM2.5 NAAQS. Accordingly, this action only
pertains to that specific NAAQS.

B. Clean Air Fine Particle Implementation Rule

    As noted above, on April 25, 2007, EPA issued the PM2.5
Implementation Rule for the 1997 PM2.5 NAAQS (72 FR 20586).
This rule describes the CAA framework and requirements for developing
SIPs to achieve attainment in areas designated nonattainment for the
1997 PM2.5 NAAQS. Such attainment plans must include a
demonstration that a nonattainment area will meet the applicable NAAQS
within the timeframe provided in the statute. This demonstration must
include modeling that is performed in accordance with 40 CFR 51.112
(Demonstration of adequacy) and Appendix W to part 51 (Guideline on Air
Quality Models) and that is consistent with EPA modeling guidance. See
40 CFR 51.1007. The modeling demonstration should include supporting
technical analyses and descriptions of all relevant adopted Federal,
state, and local regulations and control measures that have been
adopted in order to provide for attainment of the 1997 PM2.5
NAAQS by the proposed attainment date.
    For the 1997 PM2.5 NAAQS, an attainment demonstration
must show that a nonattainment area will attain the standards as
expeditiously as practicable, but within 5 years of designation (i.e.,
by an attainment date of no later than April 5, 2010, based on air
quality data for 2007 through 2009). If the area is not expected to
meet the NAAQS by April 5, 2010, a state may request to extend the
attainment date by 1 to 5 years based upon the severity of the
nonattainment problem or the feasibility of implementing control
measures in the specific area. CAA section 172(a)(2). For EPA to
approve an extension of the attainment date beyond 2010, the state must
provide an analysis that is consistent with the statutory criteria for
an extension and that demonstrates that the attainment date is as
expeditious as practicable for the area, given the existing facts and
circumstances.
    For each nonattainment area, the state (or each state of a multi-
state area) must demonstrate that it has adopted all RACM, including
all RACT, as needed to provide for attainment of the PM2.5
NAAQS in the area ``as expeditiously as practicable.'' The
PM2.5 Implementation Rule provides guidance for making these
RACM/RACT determinations. See discussion in section IV.A.4. below. Any
measures that are necessary to meet these requirements that are not
already federally promulgated or in an EPA-approved part of the SIP
must be submitted as part of a state's attainment plan. Any state
measures in the control strategy must meet the applicable statutory and
regulatory requirements, and, in particular, must be enforceable.
    The PM2.5 Implementation Rule also includes guidance on
precursor pollutants that states must address in their attainment
plans. Section 302(g) of the CAA authorizes EPA to regulate criteria
pollutants and their precursors. The main chemical precursors
associated with fine particle formation are sulfur dioxide
(SO2), NOX, volatile organic compounds (VOC), and
ammonia. However, the effect of reducing emissions of precursor
pollutants that contribute to PM2.5 concentrations varies by
area depending upon local PM2.5 composition, emission
levels, and other area-specific factors. For this reason, the
PM2.5 Implementation Rule requires that states control the
direct PM2.5 and SO2 emissions and also that
states control the other precursor emissions that would be most
effective for attaining the NAAQS within the specific area, based upon
an appropriate technical demonstration.
    The PM2.5 Implementation Rule defines direct
PM2.5 emissions as ``solid particles emitted directly from
an air emissions source or activity, or gaseous emissions or liquid
droplets from an air emissions source or activity which condense to
form particulate matter at ambient temperatures. Direct
PM2.5 emissions include elemental carbon, directly emitted
organic carbon, directly emitted sulfate, directly emitted nitrate, and
other inorganic particles (including but not limited to crustal
material, metals, and sea salt).'' See 40 CFR 51.1000.
    The PM2.5 Implementation Rule requires states to
identify and evaluate sources of PM2.5 direct emissions and

PM2.5 attainment plan precursors as appropriate. See 40 CFR
51.1002(c). The rule requires states to address SO2 as a
PM2.5 attainment plan precursor and to evaluate
SO2 for possible control measures in all PM2.5
nonattainment areas. States are also required to address and evaluate
reasonable controls for NOX as a PM2.5 attainment
plan precursor unless the state and EPA make a finding that
NOX emissions from sources in the state do not significantly
contribute to PM2.5 concentrations in the relevant
nonattainment area.
    Although current scientific information shows that certain VOC
emissions are precursors to the formation of secondary organic aerosol,
and significant progress has been made in understanding the role of
gaseous organic material in the formation of organic PM, this
relationship remains complex. Further research and technical tools are
needed to better characterize emissions inventories for specific VOC
and to determine the extent of the contribution of specific VOC to
organic PM mass. Because of these factors, the PM2.5
Implementation Rule does not require states to address or evaluate
controls for VOC as PM2.5 attainment plan precursors unless
the state or EPA makes a finding that VOC emissions from sources in the
state significantly contribute to PM2.5 concentrations in
the relevant nonattainment area.
    The PM2.5 Implementation Rule describes the formation of
particles related to ammonia emissions, which is a complex, nonlinear
process. Though recent studies have improved our understanding of the
role of ammonia in aerosol formation, further research is needed to
better describe the relationship between ammonia emissions and
particulate matter concentrations and the related impacts. Also, area-
specific data is needed to evaluate the effectiveness of reducing
ammonia emissions in reducing PM2.5 concentrations in
different areas and to determine where ammonia decreases may increase
the acidity of particles and precipitation. For these reasons, the
PM2.5 Implementation Rule does not require states to address
or evaluate controls for ammonia as PM2.5 attainment plan
precursors unless the state or EPA makes a finding that ammonia
emissions from sources in the state significantly contribute to
PM2.5 concentrations in the relevant nonattainment area.
    The presumptive inclusion of NOX and the presumptive
exclusion of VOC and ammonia as attainment plan precursors can be
reversed based on an acceptable technical demonstration for a
particular nonattainment area by the state or EPA. The state must
demonstrate that, based on the sum of available technical and
scientific information, it would be appropriate for a nonattainment
area to reverse the presumptive approach for a particular precursor.
Such a demonstration should include information from multiple sources,
such as results of speciation data analyses, air-quality modeling
studies, chemical-tracer studies, emissions inventories, or special
intensive measurement studies to evaluate specific atmospheric
chemistry in an area. See PM2.5 Implementation Rule, 72 FR
20596.
    The PM2.5 Implementation Rule also provides guidance for
the other elements of a state's attainment plan, including, but not
limited to, emissions inventories, contingency measures, and motor-
vehicle emissions budgets used for transportation conformity purposes.
There are, however, three aspects of the preamble to the
PM2.5 Implementation Rule for which EPA received petitions
requesting reconsideration. The specific guidance elements identified
by petitioners pertain to the presumption that compliance with the
requirements of the Clean Air Interstate Rule (CAIR) automatically
satisfies the requirements for RACT or RACM for NOX or
SO2 emissions from electric generating unit (EGU) sources
participating in regional cap and trade programs (See PM2.5
Implementation Rule, section II.F.7.); the suggestion that the economic
feasibility element of a RACT determination should include
consideration of whether the cost of a measure is reasonable in light
of the benefits (See PM2.5 Implementation Rule, section
II.F.5.); and the policy of allowing certain emission reductions from
outside the nonattainment area to be credited as meeting the RFP
requirement (See PM2.5 Implementation Rule, section
II.G.5.). EPA has granted these petitions and intends to propose
rulemaking to address these aspects of the PM2.5
Implementation Rule.

C. The Clean Air Interstate Rule and the Transport Rule

    EPA published CAIR on May 12, 2005, to address the interstate
transport requirements of the CAA. See 76 FR 70093. As originally
promulgated, CAIR requires significant reductions in emissions of
SO2 and NOX to limit the interstate transport of
these pollutants and the ozone and fine particulate matter they form in
the atmosphere. In 2008, however, the D.C. Circuit remanded CAIR back
to EPA. North Carolina v. EPA, 550 F.3d 1176. The court found CAIR to
be inconsistent with the requirements of the CAA, North Carolina v.
EPA, 531 F.3d 896 (D.C. Cir. 2008), but ultimately remanded the rule to
EPA without vacatur because it found that ``allowing CAIR to remain in
effect until it is replaced by a rule consistent with [the court's]
opinion would at least temporarily preserve the environmental values
covered by CAIR.'' North Carolina v. EPA, 550 F.3d at 1178. CAIR thus
remained in place following the remand and was in place and enforceable
through the April 5, 2010, attainment date.
    In response to the court's decision, EPA has issued a new rule to
address interstate transport of NOX and SO2 in
the eastern United States (i.e., the Transport Rule, also known as the
Cross-State Air Pollution Rule). See 76 FR 48208, August 8, 2011. In
the Transport Rule, EPA finalized regulatory changes to sunset (i.e.,
discontinue) CAIR and the CAIR FIPs for control periods in 2012 and
beyond. See 76 FR 48322.
    On December 30, 2012, the DC Circuit issued an order addressing the
status of the Transport Rule and CAIR in response to motions filed by
numerous parties seeking a stay of the Transport Rule pending judicial
review. In that order, the DC Circuit stayed the Transport Rule pending
the court's resolution of the petitions for review of that rule in EME
Homer Generation, L.P. v. EPA (No. 11-1302 and consolidated cases). The
court also indicated that EPA is expected to continue to administer
CAIR in the interim until the court rules on the petitions for review
of the Transport Rule.
    EPA does not believe that the circumstances set forth above
preclude EPA from approving the attainment plan for the Alabama portion
of the Chattanooga Area. While the monitoring data that shows the Area
attained the 1997 Annual PM2.5 NAAQS by the April 2010
attainment deadline was impacted by CAIR, CAIR was in place and
enforceable through the 2010 attainment date that is relevant to acting
on this attainment plan. Moreover, EPA's analysis conducted for the
Transport Rule demonstrates that the Chattanooga Area would be able to
attain the 1997 Annual PM2.5 NAAQS even in the absence of
either CAIR or the Transport Rule. See Appendix B to the Air Quality
Modeling Final Rule Technical Support Document for the Cross-State Air
Pollution Rule.
    Most importantly, EPA notes that this action proposes approval of
an attainment plan that demonstrated that the Chattanooga Area would
attain the 1997 Annual PM2.5 NAAQS by 2010, which the Area
did. As of 2010, CAIR

was an enforceable control measure applicable to affected sources in
the Area, as well as sources throughout the eastern U.S. As such, the
fact that CAIR is now in place only temporarily as a result of the
judicial remand of CAIR does not detract from our conclusion that the
attainment plan should be approved. Further, the fact that the court
has stayed the implementation of the Transport Rule at this time is not
relevant because, as noted above, EPA's modeling for the Transport Rule
demonstrates the Chattanooga Area would be able to attain the 1997
Annual PM2.5 even in the absence of the Transport Rule.
Finally, the Transport Rule, as promulgated, only addresses emissions
in 2012 and beyond. As such, neither the Transport Rule itself, nor the
judicial stay of the Transport Rule, is relevant to the question
addressed in this proposal notice. The purpose of this action is to
determine whether the attainment plan submitted by Alabama is
sufficient for bringing the Area into attainment by the April 2010
attainment date, a date before the Transport Rule was even promulgated.
For these reasons, neither the current status of CAIR nor the current
status of the Transport Rule affects any of the criteria for proposed
approval of this SIP revision.

D. Attaining Data Determination and Finding of Attainment

    On May 31, 2011, EPA determined that the Chattanooga Area had
attaining data for the 1997 Annual PM2.5 NAAQS. See 76 FR
31239. That determination was based on quality-assured, quality
controlled and certified ambient air monitoring data that shows the
Area met the 1997 Annual PM2.5 NAAQS. Furthermore, on
September 8, 2011, in accordance with CAA 179(c), EPA determined that
the Chattanooga Area attained the 1997 Annual PM2.5 NAAQS by
its applicable attainment date of April 5, 2010. See 76 FR 55774. This
information is mentioned here in support of EPA's determination that
Alabama's attainment plan was sufficient for the Chattanooga Area to
achieve attainment by no later than the required attainment date of
April 5, 2010.
    As discussed in the May 31, 2011, rulemaking, EPA's determination
of attainment \1\ suspended the obligation for the State to meet
planning SIP requirements for the Chattanooga Area for so long as the
Area continues to attain the 1997 Annual PM2.5 NAAQS. See 40
CFR 51.1004(c). The State must still submit required emissions
inventories consistent with applicable timelines. The suspended SIP
submission obligations include the attainment demonstration (including
in this case the mobile source insignificance determination submitted
to satisfy transportation conformity requirements), the RACM/RACT
analysis and requirements, the RFP requirements as applicable, and
contingency measures. Despite the suspension of the aforementioned
attainment plan requirements for the Chattanooga Area for the 1997
Annual PM2.5 NAAQS, Alabama has requested that EPA take
action on its planning SIP for this Area in part because the SIP
submittal includes the insignificance determination for conformity
purposes. Further, in September 2011, EPA agreed in a Consent Decree to
take action on the State's attainment plan SIP submission, including
these specific plan elements that would otherwise be suspended.
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    \1\ The determination of attainment is not a redesignation of
the Area from nonattainment to attainment and is not an indication
that the Area will continue to maintain the standard for which the
determination is made. It is merely a determination that the Area
attained the standard for a particular three year period and also by
the applicable deadline. Please see EPA's May 31, 2011, rulemaking
for more detail on the effects of a determination of attainment.
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    Monitoring data thus far available in the Air Quality System (AQS)
database for 2011 show that this Area continues to meet the 1997 Annual
PM2.5 NAAQS at this time. As shown in Table 4, found later
in this notice, ambient PM2.5 levels in the Chattanooga Area
have declined steadily since Alabama submitted its PM2.5
attainment plan in 2008.
    EPA understands that the State chose not to withdraw the attainment
plan SIP revision for the Alabama portion of the Chattanooga Area
because it includes a mobile insignificance determination for direct
PM2.5 and NOX emissions from mobile sources.
Therefore, as mentioned above, although the SIP planning requirements
for the 1997 Annual PM2.5 NAAQS have been suspended for the
Chattanooga Area, EPA is acting on these elements of Alabama's
attainment plan for the Alabama portion of the Chattanooga Area because
the State has requested it and elected not to withdraw these
elements.\2\
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    \2\ The State of Georgia withdrew its attainment plan submittal
for the Georgia portion of the Chattanooga Area on June 29, 2011.
The State of Tennessee has not yet withdrawn its attainment plan
submittal for the Tennessee portion of the Chattanooga Area,
however, EPA is not acting on that submittal at this time.
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III. What is included in Alabama's attainment plan submittal for
Jackson County?

    Alabama's attainment plan submittal for the 1997 Annual
PM2.5 NAAQS covers the Alabama portion of the Chattanooga
Area, which is the only portion of such Area for which the State has
jurisdiction. Today's action addresses only the Alabama portion of the
Chattanooga Area. However, the modeling analysis provided with
Alabama's attainment plan documentation includes modeling results for
the entire tri-state Area that also includes the results of Georgia's
and Tennessee's demonstrations for their portions of the Area, for
which the conclusions of attainment are consistent with that of
Alabama's. The analysis indicates that the entire Area across the three
states will attain the NAAQS, and thus supports this proposed approval
action.
    In accordance with section 172(c) of the CAA and the
PM2.5 Implementation Rule, the Alabama attainment plan for
the Chattanooga Area includes: (1) An emissions inventory for the
plan's base year (2002); (2) an attainment demonstration; and (3) an
insignificance finding for the mobile source contribution of direct
PM2.5 and NOX. The attainment demonstration
includes: Technical analyses that locate, identify, and quantify
sources of emissions contributing to violations of the 1997 Annual
PM2.5 NAAQS; analyses of future-year emissions reductions
and air quality improvements expected to result from national and local
programs; adopted emission reduction measures with schedules for
implementation; and contingency measures required under section
172(c)(9) of the CAA. See 72 FR 20605.
    To analyze future-year emissions reductions and air quality
improvements, Alabama used regional modeling analyses developed through
the Association for Southeastern Integrated Planning (ASIP). The ASIP
was a collaborative modeling and technical analysis effort among the
States of Alabama, Kentucky, Florida, Georgia, Mississippi, North
Carolina, South Carolina, Tennessee, Virginia, and West Virginia to
develop a regional assessment of the controls needed to achieve
attainment of the 1997 PM2.5 NAAQS and the 2008 8-hour ozone
NAAQS. This regional modeling was performed in accordance with EPA's
``Guidance on the Use of Models and Other Analyses for Demonstrating
Attainment of Air Quality Goals for Ozone, PM2.5, and
Regional Haze'' (EPA-454/B-07-002, April 2007)

(hereafter referred to as ``EPA's Modeling Guidance'').

IV. What is EPA's analysis of Alabama's attainment plan submittal for
Jackson County?

A. Attainment Demonstration

    Consistent with CAA requirements (See, e.g., section 172), and 40
CFR 51.1007, an attainment demonstration for a PM2.5
nonattainment area must include a showing that the area will attain the
1997 PM2.5 annual and 24-hour standards as expeditiously as
practicable. The demonstration must also meet the requirements of 40
CFR 51.112 and Part 51, Appendix W, and include inventory data,
modeling results, and emissions reduction analyses on which the state
has based its projected attainment. In the case of the Chattanooga
Area, the Area has already attained the 1997 PM2.5 Annual
NAAQS. Thus, EPA is now proposing that the attainment plan submitted by
Alabama was sufficient, and EPA is proposing to approve individual
components of the plan.
1. Pollutants Addressed
    As discussed in section II.B. above, the PM2.5
Implementation Rule requires states to identify and evaluate sources of
PM2.5 direct emissions and appropriate PM2.5
attainment plan precursors. The rule provides that SO2 is a
PM2.5 attainment plan precursor in all areas. The rule also
sets forth the rebuttable presumptions that NOX is a
PM2.5 attainment plan precursor in all areas and that
ammonia and VOC are not PM2.5 attainment plan precursors in
any areas. Neither Alabama nor the EPA has found reason to reverse any
of these presumptions for the Chattanooga Area. Accordingly, Alabama's
PM2.5 attainment plan evaluates emissions of direct
PM2.5, SO2, and NOX in Jackson County.
2. Emissions Inventory Requirements
    States are required under section 172(c)(3) of the CAA to develop
comprehensive, accurate and current emissions inventories of all
sources of the relevant pollutant or pollutants in the area. These
inventories provide a detailed accounting of all emissions and emission
sources by precursor or pollutant. In addition, inventories are used in
air quality modeling to demonstrate that attainment of the 1997
PM2.5 NAAQS is as expeditious as practicable and, if an
attainment date extension beyond 2010 is needed, to support the need
for such an extension. Emissions inventory guidance was provided in the
April 1999 document, ``Emissions Inventory Guidance for Implementation
of Ozone and Particulate Matter NAAQS and Regional Haze Regulations''
(EPA-454/R-99-006), which was updated in November 2005 (EPA-454/R-05-
001) (hereafter referred to as ``EPA's Emissions Inventory Guidance'').
Emissions reporting requirements were provided in the 2002 Consolidated
Emissions Reporting Rule (CERR) (67 FR 39602). On December 17, 2008 (73
FR 76539), EPA promulgated the Air Emissions Reporting Requirements
(AERR) to update emissions reporting requirements in the CERR and to
harmonize, consolidate and simplify data reporting by states.
    In accordance with the AERR and EPA's Emissions Inventory Guidance,
the PM2.5 Implementation Rule requires states to submit
inventory information on directly emitted PM2.5 and the main
PM2.5 precursors (SO2, NOX, VOC, and
ammonia) and any additional inventory information needed to support an
attainment demonstration and (where applicable) an RFP plan.
    PM2.5 is comprised of filterable and condensable
emissions. Condensable particulate matter (CPM) can comprise a
significant percentage of direct PM2.5 emissions from
certain sources and is required to be included in national emissions
inventories based on emission factors. Test Methods 201A and 202 are
available for source-specific measurement of condensable emissions.
However, the PM2.5 Implementation Rule notes that there were
issues raised by the Commenters related to availability and
implementation of these test methods as well as uncertainties in
existing data for condensable PM2.5. EPA thus established a
transition period during which EPA could assess possible revisions to
available test methods and to allow time for states to update emissions
inventories as needed to fully address direct PM2.5,
including condensable emissions. Because of the time required for this
assessment, EPA recognized that states would be limited in how to
effectively address CPM emissions and therefore established a period of
transition, up to January 1, 2011, during which state submissions for
PM2.5 were not required to address CPM emissions. Amendments
to these test methods were proposed on March 25, 2009 (74 FR 12969),
and finalized on December 21, 2010 (75 FR 80118). The amendments to
Method 201A added a particle-sizing device for PM2.5
sampling, and the amendments to Method 202 revised the sample
collection and recovery procedures of the method to reduce the
formation of reaction artifacts that could lead to inaccurate
measurements of CPM emissions.
    The period of transition for establishing emission limits for
condensable direct PM2.5 ended on January 1, 2011. Under the
PM2.5 Implementation rule, PM2.5 submissions made
during the transition period are not required to address CPM emissions;
however, states must address the control of direct PM2.5
emissions, including condensable emissions, with any new action taken
after January 1, 2011. Alabama submitted its Chattanooga Area
attainment plan prior to January 1, 2011, and accordingly did not
consider CPM in addressing the control of PM2.5 emissions.
    In July 2008, EarthJustice filed a petition requesting
reconsideration of EPA's transition period for CPM emissions provided
in the PM2.5 Implementation Rule. In January 2009, EPA
decided to allow states that have not previously addressed CPM to
continue to exclude CPM for Prevention of Significant Deterioration
permitting during the transition period. Today's action reflects a
review of Alabama's submittal based on applicable EPA guidance as
described in the PM2.5 Implementation Rule and at the time
of Alabama's submittal.
    The 172(c)(3) emissions inventory is developed by the incorporation
of data from multiple sources. States were required to develop and
submit to EPA a triennial emissions inventory according to the AERR for
all source categories (i.e., point, area, nonroad mobile and on-road
mobile). This inventory often forms the basis of data that are updated
with more recent information and data that also is used in the
attainment demonstration modeling inventory. Such was the case in the
development of the 2002 emissions inventory that the State submitted as
part of the attainment plan for this Area. The State based the 2002
emissions inventory on data developed with Visibility Improvement State
and Tribal Association of the Southeast (VISTAS) contractors for the
same ten states of the ASIP effort and submitted by the states to the
2002 National Emissions Inventory. Several iterations of the 2002
inventories were developed by VISTAS for the different emission source
categories resulting from revisions and updates to the data. This
resulted in version G2 of the updated data, which VISTAS and states
used to represent point source emissions. Data from many databases,
studies and models (e.g., vehicle miles traveled, fuel programs, the
NONROAD 2002 model data for commercial marine vessels, locomotives and
Clean Air Market Division, etc.)

resulted in the emissions inventory submitted by the State as part of
this attainment plan. The data were developed by VISTAS according to
EPA's Emissions Inventory Guidance and a quality assurance project plan
that was developed through VISTAS and approved by EPA. EPA agrees that
the process used to develop this emissions inventory was adequate to
meet the requirements of the CAA, e.g., CAA section 172(c)(3), and the
implementing regulations.
    Table 1 below shows the level of emissions, expressed in tons per
year (tpy), in the Alabama portion of the Chattanooga Area for the 2002
base year by pollutant and emissions source category, as provided in
the October 7, 2009, attainment plan. As stated earlier in this notice,
EPA approved the base year emissions inventory for the Alabama portion
of the Chattanooga Area on February 8, 2012 (77 FR 6469), as meeting
the requirements of section 172(c)(3) of the CAA. The emissions
inventory was approved because the State developed the emissions
inventory consistent with the CAA, implementing regulations, and EPA
guidance for emissions inventories.

      Table 1--Base Year (2002) Actual Emissions Inventory for the Alabama Portion of the Chattanooga Area
----------------------------------------------------------------------------------------------------------------
         Source category             NOX (tpy)       SO2 (tpy)      PM2.5 (tpy)      VOC (tpy)     Ammonia (tpy)
----------------------------------------------------------------------------------------------------------------
Point...........................          26,337          44,080             933             144               2
Area............................              10              17              38              98              38
Mobile..........................               7               6               0              18               0
Nonroad.........................              41               5               3              47               0
                                 -------------------------------------------------------------------------------
    Total.......................          26,395          44,108             974             307              40
----------------------------------------------------------------------------------------------------------------

    Table 2 below shows the level of emissions projected by VISTAS and
the State for the 2009 attainment year. While the projections for the
two point sources in the Alabama portion of the Chattanooga Area
indicated a slight increase in SO2 and direct
PM2.5 emissions, the overall 2009 statewide emission
projections for Alabama, Tennessee and Georgia indicated significant
decreases in SO2 emissions. The projected 2009 emissions
inventories were used by VISTAS in the modeling demonstration of
attainment for the Area by that year. Although the projected 2009
emissions of SO2 and direct PM2.5 from point
sources in the Alabama portion of the Chattanooga Area indicated a
slight increase from the 2002 actual emissions, the actual 2009
emissions that are now recorded in AQS show that significant reductions
occurred in these pollutant emissions.

  Table 2--Attainment Year (2009) Projected Emissions Inventory for the Alabama Portion of the Chattanooga Area
----------------------------------------------------------------------------------------------------------------
         Source category             NOX (tpy)       SO2 (tpy)      PM2.5 (tpy)      VOC (tpy)     Ammonia (tpy)
----------------------------------------------------------------------------------------------------------------
Point...........................           5,157          45,356           1,124             177               8
Area............................              10              16              39              69              41
Mobile..........................               5               1               0              11               1
Nonroad.........................              38               2               2              37               0
                                 -------------------------------------------------------------------------------
    Total.......................           5,210          45,375           1,165             294              50
----------------------------------------------------------------------------------------------------------------

    Additional emissions inventory information for the Alabama portion
of the Chattanooga Area is included in Appendix 3 of Alabama's
attainment SIP submittal. Emissions inventories for the Tennessee and
Georgia portions of the Area are included in Appendices 1 and 2,
respectively, of Alabama's attainment SIP submittal. This additional
information is available in the docket for this final action (EPA-R04-
OAR-2011-0084) on the www.regulations.gov Web site.
3. Modeling
    The PM2.5 attainment demonstrations must include
modeling that should be developed in accordance with EPA's Modeling
Guidance. A brief description of the modeling used to support Alabama's
attainment demonstration follows. More detailed information can be
found in Alabama's October 7, 2009, SIP revision in the docket for this
proposed action (EPA-R04-OAR-2011-0084) on the www.regulations.gov Web
site.
    Ambient PM2.5 typically includes both primary (directly
emitted) PM2.5 and secondary PM2.5 (e.g.,
sulfates (SO4) and nitrates (NO3) formed by
chemical reactions in the atmosphere). Some of the physicochemical
processes leading to the formation of secondary PM2.5 may
take hours or days, as may some of the removal processes. Thus, some
sources of secondary PM2.5 may be sources outside of the
nonattainment area. To model a sufficient geographic area to take these
processes into account, Alabama's regional modeling domain covered an
area slightly greater than the geographical area of the VISTAS/ASIP
states in this attainment demonstration.
    Alabama, through the ASIP and VISTAS, conducted an analysis of the
major contributing components of PM2.5 in the Alabama
portion of the Chattanooga Area. Specifically, organic carbon (OC) and
SO4 account for the largest contributions. The majority of
OC can be attributed to biogenic emissions and SO4 to
emissions of SO2. SO2 emissions are primarily
associated with the point source sector. Emissions sensitivity modeling
for the Chattanooga Area indicated that SO2 emissions
reductions from EGUs in Alabama, Georgia, Tennessee, and Kentucky would
have the greatest benefits for the Area. The VISTAS modeling also
projects limited benefits to total ambient PM2.5 from
reductions of NOX emissions. See Figure 6-1 of the SIP
Narrative of Alabama's attainment SIP submittal. EPA preliminarily
agrees

with Alabama's assertion that controlling SO2 from point
sources is the most effective means of addressing attainment of the
1997 Annual PM2.5 NAAQS in the Chattanooga Area.
Model Selection and Inputs
    The ASIP performed modeling for ozone and PM2.5 for the
10 collaborating southeastern states, including Alabama. The modeling
analysis is a complex technical evaluation that began with selection of
the modeling system. The ASIP and/or VISTAS used the following modeling
system:
     Meteorological Model: The Pennsylvania State University/
National Center for Atmospheric Research Mesoscale Meteorological Model
is a nonhydrostatic, prognostic meteorological model routinely used for
urban- and regional-scale photochemical, ozone, PM2.5, and
regional haze regulatory modeling studies.
     Emissions Model: The Sparse Matrix Operator Kernel
Emissions modeling system is an emissions modeling system that
generates hourly gridded speciated emission inputs of mobile, non-road
mobile, area, point, fire and biogenic emission sources for
photochemical grid models.
     Air Quality Model: The EPA's Models-3/Community Multiscale
Air Quality (CMAQ) modeling system is a photochemical grid model
capable of addressing ozone, particulate matter, visibility and acid
deposition at a regional scale. The photochemical model selected for
this study was CMAQ version 4.5. It was modified through VISTAS with a
module for Secondary Organics Aerosols in an open and transparent
manner that was also subjected to outside peer review.
    CMAQ modeling of regional haze in the VISTAS region for 2002 and
2009 was carried out on a grid of 12x12 kilometer cells that covers the
ten VISTAS states and states adjacent to them. This grid is nested
within a larger national CMAQ modeling grid of 36x36 kilometer grid
cells that covers the continental United States, portions of Canada and
Mexico, and portions of the Atlantic and Pacific Oceans along the east
and west coasts. Selection of a representative period of meteorology is
crucial for evaluating baseline air quality conditions and projecting
future changes in air quality due to changes in emissions of
visibility-impairing pollutants. Based upon an in-depth statistical
analysis tool referred to as Classification and Regression Tree (CART)
analysis, VISTAS evaluated and compared the years 2000 through 2004 and
selected calendar year 2002 as the most representative meteorological
year available for conducting the CMAQ modeling. See Georgia's State
Implementation Plan for the Chattanooga PM2.5 Nonattainment
Area for Catoosa and Walker Counties, Appendix D, Chapter 4, which is
Appendix 2 to the Alabama attainment plan submittal. As noted above,
the VISTAS and ASIP states modeling was developed consistent with EPA's
Emissions Inventory Guidance and EPA's Modeling Guidance.
    VISTAS examined the model performance of the regional modeling for
the areas of interest before determining whether the CMAQ model results
were suitable for use in the assessment of attainment of the
PM2.5 NAAQS and for use in the modeling assessment. The
modeling assessment predicts future levels of emissions and visibility
impairment used to support the 2009 PM2.5 control strategy.
In keeping with the objective of the CMAQ modeling platform, the air
quality model performance was evaluated using graphical and statistical
assessments based on measured ozone, fine particles, and acid
deposition from various monitoring networks and databases for the 2002
base year. A diverse set of statistical parameters from the EPA's
Modeling Guidance was used to stress and examine the model and modeling
inputs. Once the model performance of the 2002 base year was determined
by VISTAS to be acceptable, the EPA model attainment test was used to
assess whether attainment of the PM2.5 NAAQS would be
achieved in 2009.
    Alabama provided the appropriate supporting documentation for all
required analyses performed by the State and also provided, in
appendices to their submittal as corroborating information, the final
Tennessee and Georgia attainment demonstration SIPs for the Chattanooga
Area. The technical analyses and modeling used to assess attainment in
2009 for the Area is consistent with the CAA, EPA's PM2.5
Implementation Rule and EPA's Modeling Guidance. EPA proposes to accept
the VISTAS and ASIP technical modeling to support the attainment SIP
for the Area because the modeling system was chosen and simulated
according to EPA's Modeling Guidance. For purposes of the Chattanooga
attainment demonstration, EPA preliminarily agrees with the VISTAS
model performance procedures and results, and preliminarily agrees that
the CMAQ is an appropriate tool for the assessment of PM2.5
for the Alabama attainment demonstration for this Area. Additional
details on the ASIP and VISTAS modeling is included in Appendices 1 and
2 of the Alabama SIP, which are the final attainment demonstration SIPs
for the Chattanooga Area adopted by the States of Tennessee and
Georgia, respectively. Due in part to the location of the ambient
PM2.5 monitors and the significant pollution sources in
Tennessee and Georgia, these states completed their attainment
demonstration SIPs before Alabama. Because all three states relied upon
the same ASIP/VISTAS modeling as the basis for the attainment
demonstration for this tri-state nonattainment area, Alabama included
the Tennessee and Georgia submittals as appendices to their submittal.
Modeling Results
    The modeling results were used in a relative sense in concert with
observed ambient air quality data (i.e., taking the ratio of the
modeled future PM2.5 concentration to the modeled present
PM2.5 concentration and multiplying that by a
PM2.5 ``baseline design value''). EPA recommends using a
baseline design value that is the average of the three design value
periods that straddle the baseline inventory year (e.g., the average of
the 2000-2002, 2001-2003, and 2002-2004 design value periods for a 2002
baseline inventory year). This average design value best represents the
baseline concentrations while taking into account the variability of
meteorology and emissions (over a five-year period). This EPA
attainment test approach should reduce some of the uncertainty involved
with using absolute model predictions alone. Using the model in a
relative sense also reduces the effects of uneven model performance and
possible major biases in predicting absolute concentrations of one or
more components. The ratio of future to present model predicted air
quality resulted in relative reduction factors (RRF). The
multiplication of the RRF by an ambient design value from the base year
(i.e., 2002) provided estimates of future design values to determine if
areas with monitors in the nonattainment area will comply with the 1997
Annual PM2.5 NAAQS.
    EPA provided guidance to states and tribes for projecting
PM2.5 concentrations using a ``speciated modeled attainment
test'' (SMAT) (EPA-454/B-07-002, April 2007). Once modeling for a
projection year and a base year are complete, RRFs are computed for
each component of PM2.5 in the modeling domain. Modeling
presented by Alabama, corroborated by Tennessee and Georgia as
supplemental modeling (See Appendices 1 and 2 of the Alabama SIP in the
docket), was used to assess attainment in the entire

Chattanooga Area and used the following components of PM2.5:
SO4, NO3, directly emitted organic particles, and
directly emitted inorganic particles. Ammonia is treated as part of
SO4 and NO3 molecules, and water is assumed to be
present at a constant mass in both the base year and projection year.
For each monitoring location, the RRF for a component is computed as
the ratio of the projection year divided by the base year modeled
concentration for a three-cell by three-cell array of modeled grid
cells centered on the monitoring location.
    Projection year component concentrations are estimated by
multiplying the RRFs by a monitoring based base year component
concentration, determined by applying measured speciation data to the
monitored total PM2.5 design concentration. The sum of these
estimated projection year component concentrations is the estimated
projection year PM2.5 concentration. If future estimates of
PM2.5 concentrations are less than the 1997 PM2.5
NAAQS, then the modeling indicates attainment of the standard.
    PM2.5 includes a mixture of components that can behave
independently from one another (e.g., primary vs. secondary particles)
or that are related to one another in a complex way (e.g., different
secondary particles). Thus, it is appropriate to consider the predicted
future concentration of PM2.5 to be the sum of the predicted
component concentrations. See 72 FR 20608. As recommended in EPA's
Modeling Guidance, Alabama divided PM2.5 into its major
components and noted the future effects of already implemented control
strategies on each. The effect on PM2.5 was estimated as a
sum of the effects on individual components. Future PM2.5
design values at specified monitoring sites were estimated by adding
the future-year values of seven PM2.5 components (mass
associated with SO4, NO3, ammonium
(NH4), OC, elemental carbon (EC), particle-bound water (PBW)
and ``other'' primary inorganic particulate matter (crustal) plus
passively collected mass). All future site-specific PM2.5
design values were below the concentration specified in the NAAQS;
therefore, the Chattanooga Area passed the SMAT evaluation. Table 3
illustrates the comparison of the designation design value for 2003
with the future model-predicted 2009 annual design values for the
monitors in the nonattainment area. Compliance with the
PM2.5 annual NAAQS is predicted.
    EPA has also developed a software package called Modeled Attainment
Test Software (MATS) which will spatially interpolate data, adjust the
spatial fields based on model output gradients and multiply the fields
by model calculated RRFs. EPA recommended that the State provide MATS
attainment test values for 2009, but the tool became available soon
after Alabama had drafted its attainment plan. The State did not submit
any MATS results in the Chattanooga SIP. However, the final report for
the ``Technical Support Document for the Association for Southeastern
Integrated Planning (ASIP) Emissions and Air Quality Modeling to
Support PM2.5 and 8-Hour Ozone State Implementation Plans''
(ASIP Report which is included in the docket) provides 2009 MATS
version 1.2.1 results for the entire Chattanooga Area and the entire
ASIP/VISTAS modeling domain. As shown in Table 5-1 of this document,
MATS also indicates attainment of the annual PM2.5 NAAQS in
2009. EPA also reviewed additional regional modeling to support the
CMAQ attainment results based on the CAMx model developed and
documented in the ASIP Report. Application of the modeled attainment
test with the CAMx model also produced future design values in 2009
that were below the annual PM2.5 NAAQS. This further
supports the State's technical analysis showing that the Chattanooga
Area would achieve the 1997 Annual PM2.5 NAAQS in 2009.

                    Table 3--2003 Actual and 2009 Model-Predicted Annual PM2.5 Design Values
                                                  [[mu]g/m\3\]
----------------------------------------------------------------------------------------------------------------
              Monitor ID                     State                County               2003            2009
----------------------------------------------------------------------------------------------------------------
470654002............................  TN                Hamilton...............            15.2            13.6
470650031............................  TN                Hamilton...............            16.1            14.4
470651011............................  TN                Hamilton...............            14.1            12.3
132950002............................  GA                Walker.................            15.5            13.9
----------------------------------------------------------------------------------------------------------------

EPA Analysis
    The modeling system was chosen and simulated by VISTAS to develop a
model performance evaluation of the nonattainment area which would
provide the necessary assurances that an assessment of future controls
demonstrated attainment. Application of the EPA modeled attainment test
and the MATS indicated future design values that are less than 15.0
[mu]g/m\3\ and therefore consistent with attainment of the 1997 Annual
PM2.5 NAAQS. Finally, the Area's monitored status as having
timely attained the standard further supports the modeling results.
Current Air Quality Analysis
    As noted in section II.D. above, on May 31, 2011, EPA determined
that the Chattanooga Area had attaining data for the 1997 Annual
PM2.5 NAAQS based upon data for the 3-year period 2007-2009,
with a design value (i.e., the highest 3-year average of annual mean
PM2.5 concentrations) of 12.7 [mu]g/m\3\. EPA's review of
more recent data shows that the Area also had attaining data for the 3-
year period 2008-2010, with a design value of 11.1 [mu]g/m\3\. These
data, which have been quality-assured, certified, and recorded in EPA's
AQS, are summarized in Table 4 below. In addition, monitoring data thus
far available, but not yet certified, in the AQS database for 2011 show
that this Area continues to meet the 1997 Annual PM2.5
NAAQS. While the data that shows the Chattanooga Area attained the 1997
Annual PM2.5 NAAQS by the April 2010 attainment deadline, as
well as the more recent data, are impacted by CAIR, as described above
in section II.C. of this notice, CAIR was enforceable though the
attainment year, and EPA's modeling analysis for the Transport Rule
demonstrates that the Chattanooga Area would be able to attain the 1997
Annual PM2.5 NAAQS even in the absence of CAIR or the
Transport Rule. Further, the continuing decrease in PM2.5
concentrations in the Area also supports Alabama's determination that
current emission control measures on sources were sufficient to bring
the Chattanooga Area into attainment by no later than the required
attainment date of April 5, 2010.

                                        Table 4--2007-2009 Annual Average Concentrations in the Chattanooga Area
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                Design values (average of three consecutive annual average
                                                                                concentrations) ([mu]g/m\3\)
                 Site name                             County                Site No.    ---------------------------------------------------------------
                                                                                2008            2009            2010           2011 *
--------------------------------------------------------------------------------------------------------------------------------------------------------
Siskin Drive..............................  Hamilton, TN................     47-065-4002            14.3            12.7            11.6            11.1
Tombras Avenue............................  Hamilton, TN................     47-065-0031            14.0            12.6            11.6            11.2
Soddy-Daisy High School...................  Hamilton, TN................     47-065-1011            13.0            11.7            11.4            11.0
Rossville.................................  Walker, GA..................     13-295-0002            13.5            12.3            10.7            10.1
--------------------------------------------------------------------------------------------------------------------------------------------------------
* Monitoring data for 2011 are available but not yet certified in the AQS database.

4. Reasonably Available Control Measures/Reasonably Available Control
Technology (RACM/RACT)
a. Requirements for RACM/RACT
    CAA section 172(c)(1) requires that each attainment plan ``provide
for the implementation of all reasonably available control measures as
expeditiously as practicable (including such reductions in emissions
from the existing sources in the area as may be obtained through the
adoption, at a minimum, of reasonably available control technology),
and shall provide for attainment of the national primary ambient air
quality standards.'' EPA interprets RACM, including RACT, under section
172 as measures that a state finds are both reasonably available and
contribute to attainment as expeditiously as practicable in the
nonattainment area. Thus, what constitutes RACM or RACT in a specific
PM2.5 nonattainment area is closely tied to the expeditious
attainment demonstration of the plan. See 40 CFR 51.1010; 72 FR 20586,
20612 (April 25, 2007).
    States are required to evaluate RACM/RACT for direct
PM2.5 emissions and all of the area's attainment plan
precursors. See 40 CFR 51.1002(c); 72 FR 20586, 20589-97. The state
must address SO2 as a PM2.5 attainment plan
precursor and evaluate sources of SO2 emissions in the state
for control measures. The state must address NOX as a
PM2.5 attainment plan precursor and evaluate sources of
NOX emissions in the state for control measures, unless the
state and EPA provide an appropriate technical demonstration for a
specific area showing that NOX emissions from sources in the
state do not significantly contribute to PM2.5
concentrations in the nonattainment area. Also, because EPA concluded
that VOC and ammonia are presumptively not regulatory precursors for
PM2.5, the state is not required to evaluate RACM/RACT for
sources of VOC or ammonia unless there is a determination by either the
state or EPA supported by an appropriate demonstration that such
emissions need to be regulated for expeditious attainment of the NAAQS
in the specific area.
    For PM2.5 attainment plans, the PM2.5
Implementation Rule requires a combined approach to RACM and RACT under
subpart 1 of Part D of the CAA (``Plan Requirements for Nonattainment
Areas/Nonattainment Areas in General''). Subpart 1, unlike subparts 2
and 4, does not identify specific source categories for which EPA must
issue control technique documents or guidelines and does not identify
specific source categories for state and EPA evaluation during
attainment plan development. See 72 FR 20586, 20610. Rather, under
subpart 1, EPA considers RACT to be part of an area's overall RACM
obligation consistent with the section 172(c)(1) definition. Because
the variable nature of the PM2.5 problem in different
nonattainment areas may require states to develop attainment plans that
address widely disparate circumstances, EPA determined not only that
states should have flexibility with respect to RACM/RACT controls
consistent with the statute but also that in areas needing significant
emission reductions RACM/RACT controls on smaller sources may be
necessary to reach attainment as expeditiously as practicable. See 72
FR 20586, 20612 and 20615. Thus, under the PM2.5
Implementation Rule, RACT and RACM are those reasonably available
measures that contribute to attainment as expeditiously as practicable
in the specific nonattainment area. See 40 CFR 51.1010; 72 FR 20586,
20612.
    The PM2.5 Implementation Rule requires that attainment
plans include the list of measures that a state considered and
information sufficient to show that the state met all requirements for
the determination of what constitutes RACM/RACT in a specific
nonattainment area. See 40 CFR 51.1010(a). In addition, the rule
requires that the state, in determining whether a particular emissions
reduction measure or set of measures must be adopted as RACM/RACT,
consider the cumulative impact of implementing the available measures
and to adopt as RACM/RACT any potential measures that are reasonably
available considering technological and economic feasibility if,
considered collectively, they would advance the attainment date by one
year or more. If a measure or measures is not necessary for expeditious
attainment of the NAAQS in the area, then by definition that measure is
not RACM/RACT for purposes of the 1997 PM2.5 NAAQS in that
area. Any measures that are necessary to meet these requirements which
are not already either federally promulgated, part of the state's SIP,
or otherwise creditable in SIPs must be submitted in enforceable form
as part of a state's attainment plan for the area. See 72 FR 20586,
20614.
    Guidance provided in the PM2.5 Implementation Rule for
evaluating RACM/RACT level controls for an area also indicates that
there could be flexibility with respect to those areas that were
predicted to attain the 1997 PM2.5 NAAQS within five years
of designation as a result of existing national or local measures,
i.e., by April 2010 based upon monitoring data from 2007, 2008, and
2009. See 72 FR 20586, 20612. In such circumstances, EPA indicated that
the state may conduct a more limited RACM/RACT analysis that does not
involve additional air quality modeling. Moreover, the RACM/RACT
analysis for such an area could focus on a review of reasonably
available measures, the estimation of potential emissions reductions,
and the evaluation of the time needed to implement the measures. Thus,
the PM2.5 Implementation Rule guidance recommends that an
analysis for those areas expected to attain within five years of
designation as a nonattainment area for the 1997 PM2.5 NAAQS
may be less rigorous than for areas expected to attain later.
    A more comprehensive discussion of the RACM/RACT requirement for
PM2.5 attainment plans and EPA's guidance for it can be
found in the preamble to the PM2.5 Implementation Rule. 72
FR 20586, 20609-20633.

b. Alabama's Analysis of Pollutants and Sources for Jackson County
    Alabama's analysis appears in chapter 6 of the October 7, 2009,
attainment plan submission. The State determined that controls on
sources of VOC and sources of ammonia would not be necessary for
expeditious attainment of the NAAQS in this area. Thus, the State
determined that control of PM2.5, SO2, and
NOX, are appropriate in the Chattanooga Area for purposes of
attaining the 1997 PM2.5 NAAQS. EPA preliminarily agrees
that Alabama's determination is supported by its analysis. The State's
determination with respect to which pollutants the plan should evaluate
is discussed in chapter 5 of the submittal.
    The Alabama portion of the Chattanooga Area is limited to one
census block in Jackson County described by U.S. Census 2000 block
group identifier 01-071-9503-1. As indicated in Chapter 6 of the
Technical Support Document for the air quality designations promulgated
by EPA on January 5, 2005, this census block was included in the
Chattanooga nonattainment area to encompass the Tennessee Valley
Authority's (TVA's) Widows Creek power plant, which EPA determined to
be contributing to violations of the 1997 Annual PM2.5 NAAQS
at monitors in the nearby Tennessee and Georgia portions of the
Chattanooga Area.
c. Alabama's Evaluation of RACM/RACT Control Measures for Jackson
County
    As was noted earlier, EPA included U.S. Census block 01-071-9503-1,
in Jackson County, as part of the Chattanooga Area primarily because of
emissions from the TVA Widows Creek power plant. For this reason,
Alabama's consideration of RACM/RACT control measures for the Area
focused on the Widows Creek facility. Alabama's RACM/RACT analysis is
provided in Chapter 6 of the State's October 7, 2009, submittal. The
Widows Creek facility has a title V permit which includes requirements
to operate certain control devices, as well as key emission limits. The
facility was also included as part of the 2011 systemwide settlement
with EPA which resulted in additional requirements for the facility
that either will be or are already included into the title V permit to
ensure they are permanent and enforceable. See, e.g., http://www.epa.gov/compliance/resources/agreements/caa/tva-ffca.pdf.
    As identified in the submittal, TVA Widows Creek has two base load
units, Units 07 and 08, with rated capacities of 575 megawatts (MW) and
550 MW, respectively. The facility also has six smaller units, Units 01
through 06, which are peaking units with rated capacities of 141 MW
each. The attainment year emissions for these units are shown in Table
5 below.

  Table 5--Attainment Year (2009) Actual Emissions From Utility EGUs in
             the Alabama Portion of the Chattanooga Area \3\
------------------------------------------------------------------------
                                               NOX       SO2     PM2.5*
                   Unit                       (tpy)     (tpy)     (tpy)
------------------------------------------------------------------------
01........................................     248.5     599.3      59.9
02........................................     274.5     686.1      68.8
03........................................     109.2     250.0      25.9
04........................................     411.6    1022.0     102.1
05........................................     182.0     433.6      48.9
06........................................     893.8    2564.1     272.2
07........................................     934.7    5368.1     266.6
08........................................     472.1    1938.3     348.4
------------------------------------------------------------------------
* The PM2.5 values are a total of the filterable and condensable
  components.

    Alabama reviewed the control equipment installed on the EGUs at the
TVA Widows Creek power plant and provided the following information in
the summary of the State's analysis. Control of NOX
emissions is achieved by selective catalytic reduction (SCR) controls,
which were installed on Units 07 and 08 in 2003 and 2004, respectively.
Control of SO2 emissions is achieved by flue gas
desulfurization (FGD) controls, which were installed on Units 07 and 08
in 1984 and 1977, respectively. Control of direct PM2.5
emissions is achieved by electrostatic precipitator (ESP) controls on
Units 01 through 07 and by FGD on Unit 08. The submittal states that
the FGD installed on Unit 08 was upgraded in efficiency in 2004.
Alabama concluded that these controls, and other associated
requirements such as emission limits, were sufficient to comply with
RACM/RACT requirements and that no further controls were needed at the
facility to demonstrate timely attainment. EPA also evaluated the
Widows Creek controls, and a summary of that evaluation follows the
discussion below.
---------------------------------------------------------------------------

    \3\ Table 5 shows actual emissions data obtained from EPA's
National Emission Inventory, which is available at http://www.epa.gov/ttn/chief/.
---------------------------------------------------------------------------

    While Alabama did analyze existing controls at the TVA Widows Creek
power plant for the purpose of its RACM/RACT evaluation, EPA disagrees
with Alabama's conclusion that ``CAIR equals RACT'' for several
reasons. These reasons are outlined below although it is not necessary
for EPA to agree with Alabama's determination on that issue in order to
approve the Jackson County attainment plan. In the preamble to the
final PM2.5 Implementation Rule, EPA indicated that in
states that fulfill their CAIR SO2 emission reduction
requirements entirely through EGU emission reductions, compliance by
EGU sources with an EPA-approved CAIR SIP or a CAIR FIP could be
presumed to satisfy the SO2 RACT/RACM requirements. 72 FR
20586 at 20623. EPA also established a similar rebuttable presumption
with respect to NOX RACT/RACM for EGUs. Id. at 20623-24. EPA
did not make any determination regarding whether RACT/RACM requirements
for any particular nonattainment area were, in fact, satisfied by CAIR,
but only established a presumption that could be rebutted by data
demonstrating that CAIR was not sufficient to satisfy RACT/RACM with
respect to a particular nonattainment area. EPA did not present
technical analysis to support this presumption. Subsequent to the
publication of that preamble language, the D.C. Circuit issued a
decision in NRDC v. EPA, 571 F.3d 1245 (D.C. Cir. 2009) holding, among
other things, that EPA's similar determination, in the ozone
implementation rule, that compliance with the NOX SIP Call
satisfied RACT for EGUs was unlawful because it was not supported by a
technical demonstration showing that the NOX SIP Call would
in fact achieve greater reductions than source-by-source RACT within
the nonattainment areas. Because the presumption established by EPA in
the PM2.5 Implementation Rule was similar, in that it was
supported by reasoning but not by a technical analysis, approving a
state RACT/RACM determination based on the ``CAIR equals RACT''
presumption would be inconsistent with the court's ruling in NRDC v.
EPA. In addition, EPA received a petition for reconsideration in June
of 2007 that explicitly called into question the basis for the
presumption on both procedural and substantive grounds. In light of the
arguments raised in that petition for reconsideration, and in light of
the aforementioned court decision, EPA has granted the petition for
reconsideration on this issue and intends to initiate rulemaking to
propose changes to this aspect of the guidance for the PM2.5
Implementation Rule. Third, CAIR itself was remanded to EPA by the U.S.
Court of Appeals for the D.C. Circuit, North Carolina v. EPA, 531 F.3d
896, as amended by 550 F.3d 1178 (D.C. Cir. 2008). While the court
found serious flaws in the rule, it decided to leave CAIR in place
while EPA worked on a rule to replace it. Id.

As mentioned above, in August 2011, EPA published in the Federal
Register a rule to replace CAIR--the Transport Rule, also known as the
Cross-State Air Pollution Rule. 76 FR 48208. EPA did not address
whether compliance with the Transport Rule could, in any circumstances,
satisfy any RACM/RACT requirements for any sources. The Transport Rule
was subsequently stayed pending judicial review. In the order staying
the Transport Rule, the court also instructed EPA to continue
implementing CAIR while the Transport Rule is stayed. Thus, while CAIR
currently remains in place, it is in place only temporarily and thus
could not be said to satisfy the RACM/RACT requirement on a permanent
basis.
    As a result, the RACM/RACT analysis for EGUs must include an actual
evaluation of the level of emission controls on any sources located
within the nonattainment area to establish that, either individually or
as a category, these sources are controlled to the degree necessary to
meet the RACM/RACT level of control for the area. Given that the State
developed and submitted the attainment plan before the legitimacy of
the presumption in the guidance for the PM2.5 Implementation
Rule was called into question, EPA is independently evaluating these
sources as part of acting on the attainment plan rather than relying on
the statement in the SIP submittal concerning CAIR and RACT. EPA
believes that if its review of the level of SO2 and
NOX emission controls on these sources confirms that the
State's SIP already requires controls to the degree necessary to
provide for expeditious attainment of the NAAQS in the area, then EPA
may conclude that the sources are adequately controlled to meet the
RACM/RACT requirement. In other words, so long as an actual evaluation
of the EGU sources in the area demonstrates that there is a RACM/RACT
level of controls, then EPA may approve the attainment plan
notwithstanding the State's prior reliance on the presumption. EPA has
also concluded that if the area is now attaining the 1997
PM2.5 NAAQS, then this is prima facia evidence that under
section 172 the level of control on the EGU sources that produced the
attaining level of emissions would constitute RACM/RACT for purposes of
the State's attainment plan for these NAAQS. EPA notes, however, that
what constitutes RACM/RACT for the 1997 PM2.5 NAAQS would
not necessarily constitute RACM/RACT for other NAAQS because the
determination of RACM/RACT under CAA section 172 is dependent on the
attainment needs of the area.
    Because the Alabama submittal relies in part on the rebuttable
presumption articulated in the PM2.5 Implementation Rule
that ``CAIR equals RACT'' for utility EGUs--a presumption that EPA
cannot rely on for reasons explained above--EPA has evaluated the EGUs
at TVA Widows Creek for the purposes of RACM/RACT. EPA notes that
Widows Creek facility is subject to a Federal Facilities Compliance
Agreement (FFCA) between EPA and TVA (http://www.epa.gov/compliance/resources/agreements/caa/tva-ffca.pdf) and a Consent Decree between
four states, three non-governmental organizations and TVA, entered with
the United States District Court Eastern District of Tennessee at
Knoxville (Alabama et al. v. Tennessee Valley Auth., No. 3:11-cv-00170
and 171 (consolidated); available at http://www.epa.gov/compliance/resources/decrees/civil/caa/tvacoal-fired-cd.pdf). According to the
FFCA and the Consent Decree, Widows Creek Units 07 and 08 must operate
their SCR, FGD and ESP controls continuously while the emission units
are in operation. In addition, the six peaking units are scheduled to
be retired under the FFCA and the Consent Decree, two each in 2013,
2014, and 2015. This legal requirement for the current level of
controls on the EGU sources ensures that the level of controls which
enabled the Area to attain the standard will remain federally
enforceable.
    The Widows Creek facility is also subject to emission limits
applicable to the facility. As described in the facility's title V
operating permit,\4\ Units 01 through 08 at are each subject to a
particulate matter (PM) emission limit of 0.12 pounds per million
British thermal units (lb/MMBtu) heat input and a NOX
averaging plan as provided in the facility's Acid Rain permit, which is
included in the title V permit. Units 01 through 06 are subject to a
combined SO2 limit of 1.6 lb/MMBtu heat input and opacity
limit of 20 percent, and Units 07 and 08 at are each subject to an
SO2 limit of 0.9 lb/MMBtu heat input and an opacity limit of
20 percent.
---------------------------------------------------------------------------

    \4\ Major source operating permit and Statement of Basis issued
by ADEM to the TVA Widows Creek Fossil Plant, Permit No. 705-0008,
December 29, 2003.
---------------------------------------------------------------------------

    One other significant source of PM, SO2 and
NOX emissions, RockTenn CP, LLP (formerly Smurfit-Stone
Container Corporation), Stevenson Mill, exists within the Alabama
portion of the Chattanooga nonattainment area. Alabama did not evaluate
this pulp and paper manufacturing facility in its RACM/RACT analysis.
However, as with EPA's evaluation of RACM/RACT for EGUs, EPA has
concluded that if the area is now attaining the 1997 PM2.5
NAAQS, then this is prima facia evidence that under section 172 the
level of control on the sources that produced the attaining level of
emissions would constitute RACM/RACT for purposes of the State's
attainment plan for these NAAQS. As described in RockTenn CP, LLP,
Stevenson Mill's title V operating permit,\5\ the following emission
units and controls were in place at the facility to meet various
applicable emission limits for PM, SO2 and NOX at
the time that the Chattanooga Area achieved attainment:
---------------------------------------------------------------------------

    \5\ Major source operating permit and Statement of Basis issued
by ADEM to Smurfit-Stone Container Corporation, Stevenson Mill,
Permit No. 705-0014, October 6, 2010 (revised June 30, 2011, to
change name to RockTenn CP, LLP).
---------------------------------------------------------------------------

     The Number 1 Power Boiler is controlled by a combination
venturi-spin vane absorber and wet ESP-advance membrane up-flow system
to meet SIP emission limits for PM and opacity and a Prevention of
Significant Deterioration (PSD) Best Available Control Technology
(BACT) emission limit for SO2.
     The Number 2 Power Boiler is controlled by a combination
venturi-spin vane absorber and wet ESP-advance membrane up-flow system
to meet New Source Performance Standard (NSPS) limits and PSD/BACT
limits for SO2, PM, opacity, and NOX.
     The Number 1 Wood Fired Boiler is controlled by mechanical
dust collectors, a wet multiple-element variable throat venture
scrubber, and a polishing wet ESP to meet NSPS limits and PSD/BACT
limits for SO2, PM, opacity, and NOX.
     The Number 2 Wood Fired Boiler is controlled by a
multicyclone and a dry ESP to meet NSPS limits and PSD/BACT limits for
SO2, PM, and NOX and a state operating permit
limit for opacity.
     The Chemical Recovery System (CRS) is controlled by both a
dry and a wet ESP to meet PSD/BACT limits for PM. SO2
emissions from the CRS are monitored with a continuous emission
monitoring system to assure compliance with NSPS limits and PSD/BACT
limits. The CRS is also subject to PSD/BACT limits for NOX
and a SIP limit for opacity.
d. Proposed Action on RACM/RACT Demonstration and Control Strategy
    EPA is proposing to approve Alabama's conclusion that the existing
controls on emissions of PM2.5, SO2, and

NOX at the Widows Creek facility constitute RACM/RACT for
that source in the Alabama portion of the Chattanooga Area based on our
analysis described above. Further, as summarized above, EPA proposes
that no further controls would be required at the RockTenn facility and
that existing controls there are sufficient for RACM/RACT purposes for
this Area, at this time. As noted above, the most current monitoring
data for this Area indicates that it is attaining the 1997 Annual
PM2.5 NAAQS. In addition, EPA has already made a clean data
determination and a finding of attaining data for this Area confirming
that it met the NAAQS by its attainment date. See 76 FR 55774,
September 8, 2011. EPA's guidance for the PM2.5
Implementation Rule recommends that if an area is predicted through the
attainment plan to attain the standards within five years after
designation, then the state may submit a more limited RACM/RACT
analysis and the state could elect not to do additional modeling.
    In light of the fact that the Chattanooga Area attained the 1997
Annual PM2.5 NAAQS by the State's projected attainment date,
and that at this point in time no additional measures could be adopted
to attain one year sooner, EPA proposes to conclude that the attainment
plan meets the RACM/RACT requirements of the PM2.5
Implementation Rule and that the level of control in the State's
attainment plan constitutes RACM/RACT for purposes of the 1997 Annual
PM2.5 NAAQS. Because the PM2.5 Implementation
Rule defines RACM/RACT as that level of control that is necessary to
bring an area into timely attainment, and that no additional measures
could achieve attainment one year earlier, the current level of
federally enforceable controls on sources located within the Area is by
definition RACM/RACT for this Area for this purpose.
    Our proposed approval is based upon the determination that these
emission controls are in place and are, in part, the reason for the
attainment of the 1997 Annual PM2.5 NAAQS in the Chattanooga
Area. By approving these control measures as RACM/RACT for both sources
for purposes of Alabama's attainment plan, these control measures will
become permanent and enforceable SIP measures to meet the requirements
of the CAA and the PM2.5 Implementation Rule for purposes of
the 1997 Annual PM2.5 NAAQS.
5. Reasonable Further Progress
    Section 172(c)(2) of the CAA and the PM2.5
Implementation Rule require that attainment plans include a
demonstration that reasonable further progress toward meeting air
quality standards will be achieved through generally linear incremental
improvement in air quality. For the 1997 PM2.5 NAAQS, a
state is required to submit a separate RFP plan for any area for which
the state seeks an extension of the attainment date beyond 2010. The
PM2.5 Implementation Rule set forth that an area that
demonstrates attainment within five years of the date of designation
will be considered to have satisfied the RFP requirement and is not
required to submit a separate RFP plan. See 40 CFR 51.1009(b). The
Alabama attainment plan submittal for the Chattanooga Area by
demonstrated that the Area would attain the 1997 Annual
PM2.5 NAAQS by the April 5, 2010, attainment date.
Accordingly, the State was not required under the PM2.5
Implementation Rule to develop a specific RFP component of the
attainment plan for this Area. We therefore propose to approve the
State's attainment plan with respect to the RFP requirement.
6. Contingency Measures
    In accordance with section 172(c)(9) of the CAA, the
PM2.5 Implementation Rule requires that PM2.5
attainment plans include contingency measures. See 40 CFR 51.1012 and
72 FR at 20642-20646, April 25, 2007. Contingency measures are
additional measures to be implemented in the event that an area fails
to meet RFP or fails to attain a standard by its attainment date. These
measures must be fully adopted rules or control measures that can be
implemented quickly and without additional EPA or state action if the
area fails to meet RFP or fails to attain by its attainment date and
should contain trigger mechanisms and an implementation schedule. In
addition, they should be measures not already included in the SIP
control strategy for attaining the standard and should provide for
emission reductions equivalent to one year of RFP.
    The Alabama attainment plan describes the contingency measures for
the Chattanooga Area as being comprised of Georgia Rules for Air
Quality Control Chapter 391-3-1 Rule (sss) ``Multipollutant Control of
Electric Steam Generating Units.'' This rule requires additional
controls on power plants in Georgia after the end of 2008, resulting in
SO2 and NOX emission reductions that were not
required for demonstrating attainment of the annual PM2.5
NAAQS. However, as noted in section II.C. of this proposed rulemaking,
EPA made a determination, based on complete, quality-assured, quality-
controlled, and certified ambient air monitoring data for the 2007-2009
monitoring period, that the Chattanooga Area attained the 1997 Annual
PM2.5 NAAQS by the applicable attainment date of April 5,
2010. Because EPA has determined, in accordance with CAA 179(c)(1),
that the Area attained by its applicable deadline, no contingency
measures for failure to attain by this date need to be implemented, and
EPA action with respect to contingency measures is unnecessary and
would be futile and without purpose. Furthermore, as set forth in the
PM2.5 Implementation Rule, areas that attained the NAAQS by
the attainment date are considered to have satisfied the requirement to
show RFP, and as such do not need to implement contingency measures to
make further progress to attainment. Because EPA has determined that
the Area has attained by the attainment date, the contingency measures
submitted by Alabama are no longer necessary for the Chattanooga Area
to meet RFP requirements or to attain the annual PM2.5 NAAQS
by the attainment date.
7. Attainment Date
    Alabama provided a demonstration of attainment of the 1997 Annual
PM2.5 NAAQS in the Chattanooga Area by no later than five
years after the Area was designated nonattainment. In accordance with
the PM2.5 Implementation Rule, areas such as this,
demonstrating that they will attain the standard by April 5, 2010,
attainment deadline, are considered to have satisfied the requirement
to show RFP toward attainment and need not submit a separate RFP plan.
For similar reasons, such areas are also not subject under the
Implementation Rule to a requirement for a mid-course review. Given
that monitoring data confirm that the Chattanooga Area attained the
1997 Annual PM2.5 NAAQS by the date that the State
anticipated in its attainment plan, that EPA has already made an
attainment determination, and that the Area continues to attain those
NAAQS, EPA is proposing to approve the State's attainment date.

B. Insignificance Determination for the Mobile Source Contribution to
PM2.5 and NOX Emissions

    The CAA requires federal actions in nonattainment and maintenance
areas to ``conform to'' the goals of SIPs. See, e.g., CAA section 176.
This means that such actions will not cause or contribute to violations
of a NAAQS; worsen the severity of an existing violation; or delay
timely attainment of any NAAQS or any interim milestone. Actions

involving Federal Highway Administration (FHWA) or Federal Transit
Administration (FTA) funding or approval are subject to the
transportation conformity rule (40 CFR part 93, subpart A). Under this
rule, metropolitan planning organizations (MPOs) in nonattainment and
maintenance areas coordinate with state air quality and transportation
agencies, EPA, and the FHWA and FTA to demonstrate that their
metropolitan transportation plans and transportation improvement
programs (TIPs) conform to applicable SIPs. This is typically
determined by showing that estimated emissions from existing and
planned highway and transit systems are less than or equal to the motor
vehicle emissions budgets (MVEB) contained in a SIP.
    For MVEB to be approvable, they must meet, at a minimum, EPA's
adequacy criteria found at 40 CFR 93.118(e)(4). In certain instances,
the Transportation Conformity Rule allows areas to forgo establishment
of a MVEB where it is demonstrated that the regional motor vehicle
emissions for a particular pollutant or precursor are an insignificant
contributor to the air quality problem in an area. The general criteria
for insignificance determinations can be found in 40 CFR 93.109(f).
Insignificance determinations are based on a number of factors,
including the percentage of motor vehicle emissions in context of the
total SIP inventory; the current state of air quality as determined by
monitoring data for the relevant NAAQS; the absence of SIP motor
vehicle control measures; and the historical trends and future
projections of the growth of motor vehicle emissions. EPA's rationale
for providing for insignificance determinations is described in the
July 1, 2004, revision to the Transportation Conformity Rule at 69 FR
40004.\6\ Specifically, the rationale is explained on page 40061 under
the subsection entitled ``XXIII.B. Areas with Insignificant Motor
Vehicle Emissions.'' Any insignificance determination under review of
EPA is subject to the budget adequacy and approval process for EPA's
action on the SIP.
---------------------------------------------------------------------------

    \6\ Since the July 1, 2004, revision, 40 CFR 93.109 was revised
on March 24, 2010, because of the Transportation Conformity Rule
PM2.5 and PM10 Amendments update. In the 2004
preamble and rule, the insignificance determinations were outlined
in 40 CFR 93.109(k). Due to renumbering of this section in a 2012
final rulemaking, the provisions for insignificance determinations
are now located at 40 CFR 93.109(f).
---------------------------------------------------------------------------

    EPA made an insignificance finding through the transportation
conformity adequacy process for NOX and directly emitted
PM2.5 for the Alabama portion of the Chattanooga
PM2.5 nonattainment area on June 18, 2010 (75 FR 34734). As
a result of EPA's insignificance finding, the Alabama portion of the
Chattanooga Area was no longer required to perform regional emissions
analyses for either directly emitted PM2.5 or NOX
as part of future PM2.5 conformity determinations for the
1997 Annual PM2.5 NAAQS until such time that EPA reviewed
and took action on the Chattanooga Area's attainment plan (the subject
of today's proposed action). EPA's June 18, 2010, insignificance
finding for directly emitted PM2.5 and NOX
through the adequacy process (effective on July 6, 2010) only relates
to the Alabama portion of the tri-state Chattanooga Area.
    When EPA makes an insignificance determination through the adequacy
process for transportation conformity, EPA notes that such an adequacy
determination does not imply that an insignificance determination in
the SIP (i.e., in this case the attainment plan) will ultimately be
approved. In this case, consistent with EPA's adequacy review of
Alabama's October 7, 2009, attainment plan and the Agency's subsequent
thorough review of the entire SIP submission, EPA is proposing to
approve Alabama's insignificance determination for the mobile source
contribution of NOX and PM2.5 emissions to the
overall PM2.5 emissions in the Chattanooga Area. EPA
preliminarily determined that Alabama's SIP submittal meets the
criteria in the transportation conformity rules for an insignificance
finding for both NOX and PM2.5 contribution from
motor vehicles in the Alabama portion of the Chattanooga Area. That is,
EPA has preliminarily determined that the SIP submittal demonstrates
that, for NOX and PM2.5, regional motor vehicle
emissions are an insignificant contributor to the annual
PM2.5 concentrations in the Alabama portion of the Area.
This preliminary finding is based on the following factors:
     Tables 10.1.1-1 and 10.1.1-2 of Alabama's submittal
demonstrate that the on-road NOX and PM2.5
emissions in 2009 for the Alabama portion of the Area are less than 1
percent, each, of the total emissions for the Alabama portion of the
Area.
     There have been no SIP requirements for motor vehicles
control measures for the Alabama portion of the Area.
     According to the Chattanooga Area MPO's analysis, the
projected mobile source emissions to 2035 indicate that there is no
reason to expect highway motor vehicle growth that would cause a
violation of the 1997 Annual PM2.5 NAAQS.
     As described above, the Area has attained the 1997 Annual
PM2.5 standard and EPA is proposing to approve the
attainment plan for the Alabama portion of the Area.
    As discussed above, the Area is not currently required to perform a
regional emissions analysis for the Alabama portion of the Chattanooga
Area based on the adequacy determination for the finding that on-road
emissions of NOX and direct PM2.5 are
insignificant contributors to the Area's PM2.5 air quality
problem. Today, EPA is proposing to approve that insignificance finding
as part of the State's attainment plan for the Area. If finalized, such
approval would serve to confirm that the Alabama portion of the Area is
not required to perform a regional emissions analysis for either
directly emitted PM2.5 or NOX as a part of future
PM2.5 conformity determinations for the 1997 Annual
PM2.5 standard.\7\ PM2.5 hot-spot analysis will
continue to apply for required projects under 40 CFR 93.116 and
93.123(b) of the Transportation Conformity Rule.
---------------------------------------------------------------------------

    \7\ If Alabama submits a redesignation request and maintenance
plan for its portion of the tri-state Chattanooga TN GA AL
PM2.5 nonattainment area and believes that on-road
emissions of NOX and direct PM2.5 remain
insignificant during the maintenance period, the maintenance plan
will need to include information to support a finding that on-road
emissions of NOX and direct PM2.5 continue to
be insignificant during the maintenance period. The insignificance
finding for the attainment demonstration does not automatically
continue to apply to the future maintenance plan.
---------------------------------------------------------------------------

    Weighing all the factors for an insignificance finding,
particularly the minor contribution of mobile source NOX and
PM2.5, EPA has determined that the NOX and
PM2.5 contribution from motor vehicle emissions to the
Annual PM2.5 pollution problem for the Alabama portion of
the Area are insignificant. If finalized, EPA's insignificance finding
should be considered and specifically noted in the transportation
conformity documentation that is prepared for this Area.
    The insignificance determination that Alabama submitted for the
Chattanooga Area was developed with projected mobile source emissions
derived using the MOBILE6 motor vehicle emissions model. EPA is
proposing to approve the inventory and the insignificance determination
because this model was the most current model available at the time
Alabama was performing its analysis. However, EPA has now issued an
updated motor vehicle emissions model known as Motor Vehicle Emission
Simulator or MOVES. In its

announcement of this model, EPA established a two-year grace period for
continued use of MOBILE6 in regional emissions analyses for
transportation plan and TIP conformity determinations (extending to
March 2, 2012),\8\ after which states (other than California) must use
MOVES in conformity determinations for TIPs. As stated above MOBILE6.2
was the applicable mobile source emissions model that was available
when this SIP was submitted. EPA's ``Policy Guidance on the Use of
MOVES2010 and Subsequent Minor Revisions for State Implementation Plan
Development, Transportation Conformity, and Other Purposes'' (http://www.epa.gov/otaq/models/moves/documents/420b12010.pdf) explains that
the Clean Air Act does not require states that have already submitted
SIPs to revise these SIPs simply because a new motor vehicle emissions
model is now available. The guidance further states that the use of
MOBILE6.2 in an already submitted SIP should not be an obstacle to
approval of that SIP assuming that it is otherwise approvable because
it would be unreasonable to require revision to a SIP which in this
case was submitted prior to the release of MOVES. In this instance the
on-road emissions of NOX and PM2.5 represent such
a small percentage of the inventory in the Alabama portion of the Area
(less than 1 percent of the total inventory) that recalculating the on-
road emissions with MOVES would not result in a change in the proposed
conclusion that on-road emissions meet the insignificance criteria in
the transportation conformity rule. 40 CFR 93.109(f).
---------------------------------------------------------------------------

    \8\ EPA recently extended the grace period to use MOVES for
regional emissions analysis in conformity determinations to March 2,
2013 (77 FR 11394).
---------------------------------------------------------------------------

V. Proposed Action

    EPA is proposing to approve Alabama's annual PM2.5
attainment plan for the Alabama portion of the Chattanooga Area. EPA
has preliminarily determined that the SIP meets applicable requirements
of the CAA, as described in the PM2.5 Implementation Rule.
Specifically, EPA is proposing to approve Alabama's attainment
demonstration, including the RACM/RACT analysis; RFP analysis; and, for
transportation conformity purposes, an insignificance determination for
PM2.5 and NOX for the mobile source contribution
to ambient PM2.5 levels for the State's portion of the
Chattanooga Area. The requirement for a RFP plan is satisfied because
Alabama demonstrated attainment of the 1997 PM2.5 NAAQS in
the Area by April 5, 2010. Also, because EPA has previously determined
that the Area has attained by the attainment date, the contingency
measures submitted by Alabama are no longer necessary for the
Chattanooga Area to meet RFP requirements or to attain the 1997 Annual
PM2.5 NAAQS by the attainment date.

VI. Statutory and Executive Order Reviews

    Under the CAA, the Administrator is required to approve a SIP
submission that complies with the provisions of the Act and applicable
federal regulations. 42 U.S.C. 7410(k); 40 CFR 52.02(a). Thus, in
reviewing SIP submissions, EPA's role is to approve state choices,
provided that they meet the criteria of the CAA. Accordingly, this
proposed action merely approves state law as meeting federal
requirements and does not impose additional requirements beyond those
imposed by state law. For that reason, this proposed action:
     Is not a ``significant regulatory action'' subject to
review by the Office of Management and Budget under Executive Order
12866 (58 FR 51735, October 4, 1993);
     Does not impose an information collection burden under the
provisions of the Paperwork Reduction Act (44 U.S.C. 3501 et seq.);
     Is certified as not having a significant economic impact
on a substantial number of small entities under the Regulatory
Flexibility Act (5 U.S.C. 601 et seq.);
     Does not contain any unfunded mandate or significantly or
uniquely affect small governments, as described in the Unfunded
Mandates Reform Act of 1995 (Pub. L. 104-4);
     Does not have Federalism implications as specified in
Executive Order 13132 (64 FR 43255, October 7, 1999);
     Is not an economically significant regulatory action based
on health or safety risks subject to Executive Order 13045 (62 FR
19885, April 23, 1997);
     Is not a significant regulatory action subject to
Executive Order 13211 (66 FR 28355, May 22, 2001);
     Is not subject to requirements of Section 12(d) of the
National Technology Transfer and Advancement Act of 1995 (15 U.S.C. 272
note) because application of those requirements would be inconsistent
with the CAA; and
     Does not provide EPA with the discretionary authority to
address, as appropriate, disproportionate human health or environmental
effects, using practicable and legally permissible methods, under
Executive Order 12898 (59 FR 7629, February 16, 1994).
    In addition, this proposed rule does not have tribal implications
as specified by Executive Order 13175 (65 FR 67249, November 9, 2000),
because the SIP is not approved to apply in Indian country located in
the state, and EPA notes that it will not impose substantial direct
costs on tribal governments or preempt tribal law.

List of Subjects

40 CFR Part 52

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

40 CFR Part 81

    Environmental protection, Air pollution control.

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

    Dated: June 21, 2012.
A. Stanley Meiburg,
Acting Regional Administrator, Region 4.
[FR Doc. 2012-16959 Filed 7-11-12; 8:45 am]
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