Approval and Promulgation of Air Quality Implementation Plans; Pennsylvania; Adoption of the Liberty-Clairton Nonattainment Area 1997 Fine Particulate Matter National Ambient Air Quality Standard Attainment Demonstration, 68699-68710 [2011-28765]

Agencies

• ENVIRONMENTAL PROTECTION AGENCY

[Federal Register Volume 76, Number 215 (Monday, November 7, 2011)]
[Proposed Rules]
[Pages 68699-68710]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2011-28765]



[[Page 68699]]

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

ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 52

[EPA-R03-OAR-2011-0854; FRL-9488-1]


Approval and Promulgation of Air Quality Implementation Plans; 
Pennsylvania; Adoption of the Liberty-Clairton Nonattainment Area 1997 
Fine Particulate Matter National Ambient Air Quality Standard 
Attainment Demonstration

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.

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

SUMMARY: EPA is proposing to approve, with one condition, State 
Implementation Plan (SIP) revisions submitted by the Pennsylvania 
Department of Environmental Protection (PADEP) on June 17, 2011. These 
revisions include the 1997 fine particulate matter (PM2.5) 
National Ambient Air Quality Standard (NAAQS) attainment plan for the 
Liberty-Clairton nonattainment area (Liberty-Clairton Area) including a 
request for EPA to make a determination that the appropriate attainment 
deadline for this nonattainment area is April 5, 2015. EPA is proposing 
to approve the attainment plan for the Liberty-Clairton Area that 
includes the emissions inventories, the reasonably available control 
measures/reasonably available control technology (RACM/RACT), 
reasonable further progress (RFP), and contingency measures portions of 
the attainment demonstration, and the transportation conformity motor 
vehicle emissions budgets (MVEBs) that demonstrate attainment of the 
1997 PM2.5 NAAQS. EPA is proposing to conditionally approve 
the air quality modeling submitted to demonstrate attainment of the 
1997 PM2.5 NAAQS. In order for EPA to fully approve the 
modeling analysis, PADEP must update the modeling to ensure that the 
modeling results in the demonstration continue to be valid, considering 
the reductions from the Cross State Air Pollution Rule (CSAPR) rule 
that will replace the Clean Air Interstate Rule (CAIR) in 2012, and 
must submit the revised modeling to EPA within one year after the final 
conditional approval. EPA is also proposing to determine that the 
attainment date for the Liberty-Clairton Area is April 5, 2015.
    These revisions also add the definition of PM2.5, the 
1997 annual PM2.5 NAAQS of 15 micrograms per cubic meter 
([micro]g/m\3\), the 2006 24-hour NAAQS of 35 [micro]g/m\3\ and the 
related references to the list of criteria pollutant standards in the 
Allegheny County Department of Health (ACHD) regulations. EPA is 
proposing to approve the addition of the definition of PM2.5 
and inclusion of the 1997 annual and 2006 24-hour PM2.5 
NAAQS into the ACHD regulations. These actions are being taken under 
the Clean Air Act (CAA).

DATES: Written comments must be received on or before December 7, 2011.

ADDRESSES: Submit your comments, identified by Docket ID Number EPA-
R03-OAR-2011-0854 by one of the following methods:
    A. https://www.regulations.gov. Follow the on-line instructions for 
submitting comments.
    B. Email: fernandez.cristina@epa.gov.
    C. Mail: EPA-R03-OAR-2011-0854, Cristina Fernandez, Associate 
Director, Office of Air Planning, Mailcode 3AP30, U.S. Environmental 
Protection Agency, Region III, 1650 Arch Street, Philadelphia, 
Pennsylvania 19103.
    D. Hand Delivery: At the previously-listed EPA Region III address. 
Such deliveries are only accepted during the Dockets normal hours of 
operation, and special arrangements should be made for deliveries of 
boxed information.
    Instructions: Direct your comments to Docket ID No. EPA-R03-OAR-
2011-0854. EPA's policy is that all comments received will be included 
in the public docket without change, and may be made available online 
at https://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 information that you 
consider to be CBI or otherwise protected through https://www.regulations.gov or email. The https://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 https://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.
    Docket: All documents in the electronic docket are listed in the 
https://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 https://www.regulations.gov or in hard copy during normal business hours at the 
Air Protection Division, U.S. Environmental Protection Agency, Region 
III, 1650 Arch Street, Philadelphia, Pennsylvania 19103. Copies of the 
State submittal are available at the Pennsylvania Department of 
Environmental Protection, Bureau of Air Quality Control, P.O. Box 8468, 
400 Market Street, Harrisburg, Pennsylvania 17105 and the Allegheny 
County Health Department, Bureau of Environmental Quality, Division of 
Air Quality, 301 39th Street, Pittsburgh, Pennsylvania 15201.

FOR FURTHER INFORMATION CONTACT: Jacqueline Lewis at (215) 814-2037 or 
by email at lewis.jacqueline@epa.gov, or Marilyn Powers at (215) 814-
2308, or by email at powers.marilyn@epa.gov.

SUPPLEMENTARY INFORMATION: On June 17, 2011, PADEP submitted a revision 
to the Allegheny County portion of the Pennsylvania SIP. The SIP 
revision includes an attainment demonstration and base-year inventory 
for the Liberty-Clairton Area developed by ACHD, which includes an 
analysis of RACM/RACT, RFP, contingency measures to be implemented if 
violations occur after attainment or if RFP requirements are not met, 
and MVEBs for purposes of transportation conformity. In addition, the 
SIP submittal includes amendments to Allegheny County regulations that 
adopt the air quality standards and associated definitions necessary to 
implement the 1997 and 2006 PM2.5 NAAQS. Throughout this 
document, whenever ``we,'' ``us,'' or ``our'' is used, we mean EPA.

Table of Contents

I. What action is EPA proposing to take?
II. What is the background for EPA's proposed actions?
III. What is EPA's analysis of the Liberty-Clairton attainment plan 
SIP revision?
    A. Attainment Demonstration
    1. Pollutants Addressed
    2. Emission Inventories

[[Page 68700]]

    3. Control Strategy
    4. RACM/RACT
    5. Modeling
    6. Determination of the Attainment Date
    7. RFP
    B. MVEBs for Transportation Conformity
IV. Proposed Actions
V. Statutory and Executive Order Reviews

I. What action is EPA proposing to take?

    EPA is proposing to approve, with one exception, Pennsylvania's SIP 
revisions submitted to EPA on June 17, 2011 for the purpose of 
demonstrating attainment of the 1997 PM2.5 NAAQS for the 
Liberty-Clairton Area. EPA proposes to fully approve the attainment 
demonstration for the Liberty-Clairton Area that includes the base year 
emissions inventories, RACM/RACT analysis, RFP plan, contingency 
measures, and MVEBs that meet the applicable requirements of the CAA 
and the PM2.5 Implementation Rule in 40 CFR part 41, subpart 
Z. EPA proposes to conditionally approve the air quality modeling 
analysis portion of the attainment demonstration because the analysis 
relies on reductions from the CAIR, which was remanded and will be 
replaced by CSAPR in 2012. EPA proposes to determine that the 
attainment date for the 1997 PM2.5 NAAQS in the Liberty-
Clairton Area is April 5, 2015.
    EPA is also proposing to approve amendments to ACHD regulations 
that add the definition of PM2.5 and the level of the 1997 
annual and 2006 24-hour PM2.5 NAAQS. Specifically, EPA 
proposes to approve the addition of the 1997 annual PM2.5 
standard of 15 [micro]g/m\3\, the 2006 24-hour PM2.5 
standard of 35 [micro]g/m\3\, the related references to the list of 
standards in ACHD Article XXI Section 2101.10, and the new definition 
of PM2.5 to ACHD Article XXI Section 2101.20.

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

    On July 18, 1997 (62 FR 36852), EPA established new NAAQS for 
PM2.5, particulate matter with a diameter of 2.5 microns or 
less, including an annual standard of 15.0 [micro]g/m\3\ based on a 
three year average of annual mean PM2.5 concentrations and a 
24-hour (daily) standard of 65 [micro]g/m\3\ based on a three year 
average of the 98th percentile of 24-hour concentrations. See, 40 CFR 
50.7. EPA established these standards after considering substantial 
evidence from numerous health studies demonstrating that serious health 
effects are associated with exposures to PM2.5 
concentrations above the levels of these standards.
    Epidemiological studies have shown statistically significant 
correlations between elevated PM2.5 levels and premature 
mortality. Other important health effects associated with 
PM2.5 exposure include aggravation of respiratory and 
cardiovascular disease (as indicated by increased hospital admissions, 
emergency room visits, absences from school or work, and restricted 
activity days), changes in lung function and increased respiratory 
symptoms, as well as new evidence for more subtle indicators of 
cardiovascular health. Individuals particularly sensitive to 
PM2.5 exposure include older adults, people with heart and 
lung disease, and children. See, EPA, Air Quality Criteria for 
Particulate Matter, No. EPA/600/P-99/002aF and EPA/600/P-99/002bF, 
October 2004. PM2.5 can be emitted directly into the 
atmosphere as a solid or liquid particle (primary PM2.5 or 
direct PM2.5) or can be formed in the atmosphere as a result 
of various chemical reactions from precursor emissions of nitrogen 
oxides (NOx), sulfur oxides (SO2), volatile 
organic compounds (VOC), and ammonia (NH3). (72 FR 20586, 
20589, April 25, 2007).
    Following promulgation of a new or revised NAAQS, EPA is required 
by the CAA section 107(d) to designate areas throughout the nation as 
attaining or not attaining the NAAQS. On January 5, 2005 (70 FR 944), 
EPA published initial air quality designations for the 1997 
PM2.5 NAAQS, using air quality monitoring data for the 
three-year periods of 2001-2003 or 2002-2004. These designations became 
effective on April 5, 2005. On November 13, 2009 (74 FR 58688), EPA 
revised the existing designation tables in part 81 to clarify that the 
1997 designations were for both the annual PM2.5 NAAQS and 
the 24-hour PM2.5 NAAQS.
    On October 17, 2006 (71 FR 61144), EPA strengthened the 24-hour 
PM2.5 NAAQS by lowering the level to 35 [micro]g/m\3\. At 
the same time, it retained the level of the annual PM2.5 
standard at 15.0 g/m\3\. On November 13, 2009 (74 FR 58688), EPA 
designated areas, including the Liberty-Clairton Area, with respect to 
the revised 24-hour NAAQS. Pennsylvania is now required to submit an 
attainment plan for the 24-hour standard no later than three years 
after the effective date of the designation, that is, no later than 
December 14, 2012. In this notice, all references to the 
PM2.5 NAAQS are to the 1997 24-hour PM2.5 
standard of 65 [micro]g/m\3\ and annual standard of 15 [micro]g/m\3\, 
as codified in 40 CFR 50.7.
    EPA designated the Liberty-Clairton Area nonattainment for both the 
1997 annual and 24-hour PM2.5 standards. See, 40 CFR 81.305. 
The Liberty-Clairton Area is located within the Pittsburgh Beaver 
Valley Area, as a separate nonattainment area. The Liberty-Clairton 
Area was designated as a separate distinctively local-source impacted 
nonattainment area because the combination of emissions from the local 
sources in a narrow river valley creates a local air quality problem 
uniquely different from the remainder of the Pittsburgh-Beaver Valley 
Area. The Liberty-Clairton Area is home to 25,000 people about 1% the 
population of the Pittsburgh Metropolitan Statistical Area (MSA) and 
includes the boroughs of Glassport, Liberty, Lincoln, Port Vue, and the 
City of Clairton.
    EPA is implementing the 1997 PM2.5 NAAQS under Title 1, 
Part D, subpart 1 of the CAA, which includes section 172, 
``Nonattainment plan provisions.'' Section 172(a)(2) requires that a 
PM2.5 nonattainment area attain the NAAQS ``as expeditiously 
as practicable,'' but no later than five years from the date of the 
area's designation as nonattainment. This section also allows EPA to 
grant up to a five-year extension of an area's attainment date based on 
the severity of the area's nonattainment and the availability and 
feasibility of controls. EPA designated the Liberty-Clairton Area as 
nonattainment for the 1997 PM2.5 NAAQS effective April 5, 
2005, and thus the applicable attainment date is either: (a) No later 
than April 5, 2010, or (b) no later than April 5, 2015 if EPA grant a 
full five-year extension. Section 172(c) contains the general statutory 
planning requirements applicable to all nonattainment areas, including 
the requirements for emissions inventories, RACM/RACT, attainment 
demonstrations, RFP demonstrations, and contingency measures.
    On April 25, 2007, EPA issued the Clean Air Fine Particle 
Implementation Rule for the 1997 PM2.5 NAAQS. See, 72 FR 
20586, codified at 40 CFR part 51, subpart Z (PM2.5 
Implementation Rule). The PM2.5 Implementation Rule and its 
preamble address the statutory planning requirements for emissions 
inventories, RACM/RACT, attainment demonstrations including air quality 
modeling requirements, RFP demonstrations, and contingency measures. 
This rule also addresses other matters such as which PM2.5 
precursors must be addressed by the state in its attainment SIP and 
applicable attainment dates.\1\ We discuss each of

[[Page 68701]]

these CAA and regulatory requirements for PM2.5 attainment 
plan in more detail below.
---------------------------------------------------------------------------

    \1\ In June 2007, a petition to the EPA Administrator was filed 
on behalf of several public health and environmental groups 
requesting reconsideration of four provisions in the 
PM2.5 Implementation Rule. See Earthjustice, Petition for 
Reconsideration, ``In the Matter of Final Clean Air Fine Particle 
Implementation Rule,'' June 25, 2007. These provisions are (1) the 
presumption that compliance with the Clean Air Interstate Rule 
satisfies the NOX and SO2 RACT requirements 
for electric generating units; (2) the deferral of the requirement 
to establish emission limits for condensable particulate matter 
(CPM) until January 1, 2011; (3) revisions to the criteria for 
analyzing the economic feasibility of RACT; and (4) the use of out-
of-area emissions reductions to demonstrate RFP. These provisions 
are found in the PM2.5 Implementation Rule and preamble 
at 72 FR 20586 at 20623-20628, 40 CFR section 51.1002(c), 72 FR 
20586, 20619-20620 and 20636, respectively. On May 13, 2010, EPA 
granted the petition with respect to the fourth issue. Letter, Gina 
McCarthy, EPA, to David Baron and Paul Cort, Earthjustice, May 13, 
2010. On April 25, 2011, EPA granted the petition with respect to 
the first and third issues but denied the petition with respect to 
the second issue given that the deferral period for CPM emissions 
limits had already ended. Letter, Lisa P. Jackson, EPA, to Paul 
Cort, Earthjustice, April 25, 2011. EPA intends to publish a Federal 
Register notice that will announce the granting of the latter 
petition with respect to certain issues and to initiate a notice and 
comment process to consider proposed changes to the 2007 
PM2.5 Implementation Rule.
---------------------------------------------------------------------------

III. What is EPA's analysis of the Liberty-Clairton Attainment Plan SIP 
Revision?

A. Attainment Demonstration

    CAA section 172 requires a state to submit a plan for each of its 
nonattainment areas that demonstrates attainment of the applicable 
ambient air quality standard as expeditiously as practicable, but no 
later than the specified attainment date. Under the PM2.5 
Implementation Rule, this demonstration should consist of four parts:
    1. Technical analyses that locate, identify, and quantify sources 
of emissions that are contributing to violations of the 
PM2.5 NAAQS;
    2. Analyses of future year emissions reductions and air quality 
improvement resulting from already-adopted national, state, and local 
programs and from potential new state and local measures to meet the 
RACM/RACT and RFP requirements in the area;
    3. Adopted emissions reduction measures with schedules for 
implementation; and
    4. Contingency measures required under section 172(c)(9) of the 
CAA. See, 40 CFR 51.1007 and 72 FR 20586 at 20605.
1. Pollutants Addressed
    EPA recognizes NOX, SO2, VOC, and 
NH3 as the main precursor gases associated with the 
formation of secondary PM2.5 in the ambient air. These gas-
phase PM2.5 precursors undergo chemical reactions in the 
atmosphere to form secondary particulate matter. Formation of secondary 
PM2.5 depends on numerous factors including the 
concentrations of precursors; the concentrations of other gaseous 
reactive species; atmospheric conditions including solar radiation, 
temperature, and relative humidity; and the interactions of precursors 
with preexisting particles and with cloud or fog droplets. See, 72 FR 
20586 at 20589.
    As discussed previously, a state must submit emissions inventories 
for each of the four PM2.5 precursor pollutants. See, 72 FR 
20586 at 20589 and 40 CFR 51.1008(a)(1). However, the overall 
contribution of different precursors to PM2.5 formation and 
the effectiveness of alternative potential control measures will vary 
by area. Thus, the precursors that a state should regulate to attain 
the PM2.5 NAAQS can also vary to some extent from area to 
area. See, 72 FR 20586 at 20589. In the PM2.5 Implementation 
Rule, EPA did not require that all potential PM2.5 
precursors must be controlled in each specific nonattainment area. See, 
72 FR 20586 at 20589. Instead, for reasons explained in the rule's 
preamble, a state must evaluate control measures for sources of 
SO2 in addition to sources of direct PM2.5 in all 
nonattainment areas. See, 40 CFR 51.1002(c) and (c)(1). A state must 
also evaluate control measures for sources of NOX unless the 
state and/or EPA determine that control of NOX emissions 
would not significantly reduce PM2.5 concentrations in the 
specific nonattainment area. See, 40 CFR 51.1002(c)(2). In contrast, 
EPA has determined in the PM2.5 Implementation Rule that a 
state does not need to address controls for sources of VOC and 
NH3 unless the state and/or EPA make a technical 
demonstration that such controls would significantly contribute to 
reducing PM2.5 concentrations in the specific nonattainment 
area at issue. See, 40 CFR 51.1002(c)(3) and (4). Such a demonstration 
is required ``if the administrative record related to development of 
its SIP shows that the presumption is not technically justified for 
that area.'' See, 40 CFR 51.1002(c)(5). ``Significantly contributes'' 
in this context means that a significant reduction in emissions of the 
precursor from sources in the area would be projected to provide a 
significant reduction in PM2.5 concentrations in the area. 
See, 72 FR 20586 at 20590. Although EPA did not establish a 
quantitative test for determining what constitutes a significant 
change, EPA noted that even relatively small reductions in 
PM2.5 levels are estimated to result in worthwhile public 
health benefits.
    EPA further explained that a technical demonstration to reverse the 
presumption for NOX, VOC, or NH3 in any area 
could consider the emissions inventory, speciation data, modeling 
information, or other special studies such as monitoring of additional 
compounds, receptor modeling, or special monitoring studies. See, 72 FR 
20586 at 20596-20597. These factors could indicate that the emissions 
or ambient concentration contributions of a precursor, or the 
sensitivity of ambient concentrations to changes in precursor 
emissions, differs for a specific nonattainment area from the 
presumption EPA established for that precursor in the PM2.5 
Implementation Rule.
    ACHD submitted 2002 baseline inventories for each of the four 
precursor emissions and for direct PM2.5 emissions within 
the Liberty-Clairton Area. Its submission did not specifically discuss 
the presumptions in the PM2.5 Implementation Rule, however 
its discussion of the emissions inventory and control strategy 
implicitly showed that ACHD did not reverse the presumptions for 
NOX, VOC or NH3. Therefore, evaluation of control 
measures for VOC and/or NH3 was not considered, while 
NOX was considered, and, in accordance with policies 
described in the PM2.5 Implementation Rule, the Liberty-
Clairton Area PM2.5 attainment demonstration evaluated 
emissions of direct PM2.5, SO2, and 
NOX.
2. Emissions Inventories
    CAA section 172(c)(3) requires a state to submit a plan provision 
that includes a ``comprehensive, accurate, current inventory of actual 
emissions from all sources of the relevant pollutant.'' The 
PM2.5 Implementation Rule requires a state to include direct 
PM2.5 emissions and emissions of all PM2.5 
precursors in this inventory, even if it has determined that control of 
any of these precursors is not necessary for expeditious attainment. 
See, 40 CFR 51.1008(a)(1) and 72 FR 20586 at 20648. Direct 
PM2.5 includes condensable particulate matter. See, 40 CFR 
51.1000. The PM2.5 precursors are NOX, 
SO2, VOC, and NH3. The inventories should meet 
the data reporting requirements of EPA's Air Emissions Reporting 
Requirements (AERR) (71 FR 69, January 3, 2006) and include any 
additional inventory information needed to support the SIP's attainment 
demonstration and RFP demonstration. See, 40 CFR 51.1008(a)(1) and (2). 
Baseline emissions inventories are required for the attainment 
demonstration and for meeting RFP requirements. As

[[Page 68702]]

determined on the date of designation, the base year for these 
inventories should be the most recent calendar year for which a 
complete inventory was required to be submitted to EPA. The emissions 
inventory for calendar year 2002 or other suitable year should be used 
for attainment planning and RFP plans for areas initially designated 
nonattainment for the PM2.5 NAAQS in 2005. See, 40 CFR 
51.1008(b). EPA has provided additional guidance for PM2.5 
emissions inventories in the ``Emissions Inventory Guidance for 
Implementation of Ozone and Particulate Matter NAAQS and Regional Haze 
Regulations,'' November 2005 (EPA-454/R-05-001).
    The base year and future year baseline planning inventories for 
direct PM2.5 and all PM2.5 precursors for the 
Liberty-Clairton Area were included as part of this submittal. The base 
year used for the Liberty-Clairton Area SIP was 2002. ACHD developed a 
point source inventory comprised of emissions for five facilities in 
the nonattainment area, which included two major sources, two synthetic 
minor sources, and one minor source. ACHD then made corrections to the 
point source inventory for these sources to include the addition of 
condensable PM emissions.
    For the 2002 area sources, ACHD provided an inventory that 
contained estimations of emissions by multiplying an emission factor by 
some known indicator or activity level for each category at the county 
level. These estimates were apportioned to the Liberty-Clairton Area 
based on population counts.
    The 2002 Nonroad Mobile Sources emissions inventory was prepared 
with EPA's NONROAD2005 model. This model estimates fuel consumption and 
emissions of total hydrocarbons, carbon monoxide, NOX, 
SO2, and PM for all nonroad mobile source categories except 
aircraft, locomotives, and commercial marine vessels. The National 
Mobile Inventory Model was used to estimate emissions of NH3 
from sources contained in the NONROAD model. The 2002 Onroad Mobile 
Sources emissions inventory was prepared using EPA's highway mobile 
source emissions model MOBILE 6.2.
    Table 1 below shows the Liberty-Clairton Area emissions inventory 
summary for direct PM2.5 and PM2.5 precursors for 
the 2002 base year. These emissions represent emissions from sources 
only within the five-municipality Liberty-Clairton Area, not the larger 
modeled area.

                                        Table 1--Baseline 2002 Emissions
                                                   [Tons/year]
----------------------------------------------------------------------------------------------------------------
          Liberty-Clairton area (2002)              PM2.5         SO2          NOX          VOC          NH3
----------------------------------------------------------------------------------------------------------------
Stationary Point Sources.......................     2201.438     1358.522     5786.190      432.735      299.714
Area Sources...................................       36.506       81.962       80.176      336.467        7.416
Nonroad Sources................................       23.005       16.170      227.673      119.244        0.078
Mobile Sources.................................        4.918       12.077      283.422      200.841       13.867
                                                ----------------------------------------------------------------
    Totals.....................................     2265.867     1468.731     6377.461     1089.287      321.075
----------------------------------------------------------------------------------------------------------------

    Table 2 below shows the Liberty-Clairton Area emissions inventory 
summary for direct PM2.5 and PM2.5 precursors for 
the 2014 future projected year. Similar to the baseline inventory, 
these emissions represent sources only within the five municipality 
Liberty-Clairton Area.

                                    Table 2--Future Projected 2014 Emissions
                                                   [Tons/year]
----------------------------------------------------------------------------------------------------------------
          Liberty-Clairton area (2014)              PM2.5         SO2          NOX          VOC          NH3
----------------------------------------------------------------------------------------------------------------
Stationary Point Sources.......................     1328.785     1459.146     5282.002      581.492      255.456
Area Sources...................................       35.464       86.464       86.239      307.013        8.176
Nonroad Sources................................       21.500        3.034      169.006       83.335        0.093
Mobile Sources.................................        2.749        1.409      134.079       98.997       14.367
                                                ----------------------------------------------------------------
    Totals.....................................     1388.498     1550.053     5671.326     1070.837      278.092
----------------------------------------------------------------------------------------------------------------

3. Control Strategy
    To understand the PM2.5 problem in the Liberty-Clairton 
Area, EPA believes it is helpful to explain the unique topographic and 
meteorologic conditions in the area, as well as the geographic location 
of this area. The approximately 12 square kilometer area is a subset of 
Allegheny County, and is surrounded by the Pittsburgh-Beaver Valley 
nonattainment area (Pittsburgh Area). The Liberty-Clairton Area was 
designated a separate nonattainment area from the surrounding 
Pittsburgh Area because, in addition to the regional air quality 
problem, there is a localized air quality issue caused by local sources 
and by specific geologic and meteorological features of the area. The 
PM2.5 problem in the Liberty-Clairton Area is compounded by 
the sharp difference in elevation between the industrial and 
residential areas as well as large temperature differences between the 
river valleys and the adjacent hilltops. The high hillsides of the two 
rivers in the area create a significant river basin with spikes in 
localized PM2.5 concentrations that coincide with 
temperature inversions. Two of the eight monitors in the combined areas 
are located within the Liberty-Clairton Area, one in Liberty Borough 
(Liberty monitor) and one in the city of Clairton (Clairton monitor). 
On many days the Liberty monitor has readings very similar to those 
located in the Pittsburgh Area. However, when the regional 
concentrations rise, the Liberty monitor rises higher than any other 
site in the region, and after an inversion break, the monitor returns 
to a level comparable to, and sometimes less than, the concentrations 
measured at surrounding monitors in the Pittsburgh Area. The occurrence 
and severity of these high readings at the Liberty monitor, caused by 
local sources and

[[Page 68703]]

features, required that a control strategy for the Liberty-Clairton 
Area be considered separate from, and in addition to, the control 
strategy for the larger Pittsburgh Area.
    Direct PM from local sources are at the heart of the 
PM2.5 problem in this area, and the control strategy for 
attainment within the nonattainment area is to reduce emissions of 
direct PM2.5. Other than regional reductions of 
NOX and SO2 within the surrounding Pittsburgh 
Area, no additional local reductions for these pollutants are necessary 
for the Liberty-Clairton Area to attain the NAAQS by the attainment 
date. The monitored NOX and SO2 within the 
Liberty-Clairton Area are representative of the monitored 
concentrations of these precursors in the larger Pittsburgh Area. The 
small geographic size of the Liberty-Clairton Area is such that there 
is insufficient residence time for a local conversion of NOX 
and SO2 to nitrates and sulfates. This is indicated by a 
lack of sizable difference in the levels monitored at the Liberty 
monitor with the levels monitored at the Lawrenceville monitor located 
in Allegheny County, just north of Pittsburgh. Additionally, monitored 
data shows consistent trends at the Liberty monitor for sulfates and 
nitrates with those throughout the southwestern part of Pennsylvania, 
with no outlying concentrations of NOX and SO2 at 
the Liberty monitor. For the above reasons, EPA has determined that it 
is not practical to rely on local NOX and SO2 
reductions for purposes of ensuring that the Liberty-Clairton Area will 
attain the PM2.5 NAAQS by the attainment date. While 
NOX and SO2 reductions from within the 
nonattainment area are not relied upon for the Liberty-Clairton Area to 
attain the PM2.5 standard, EPA recognizes that addressing 
the control strategy for NOX and SO2 in the 
larger surrounding nonattainment area may result in collateral benefit 
in the Liberty-Clairton Area; EPA will address control strategies for 
NOX and SO2 in the surrounding nonattainment area 
when EPA takes action on the Pittsburgh Area attainment demonstration 
SIP.
    With respect to control strategies for direct PM2.5, 
ACHD has already required implementation of stringent control measures 
for the largest sources of direct PM2.5 in the Liberty-
Clairton Area, so reducing direct PM2.5 further is 
challenging. The majority of direct PM2.5 emissions 
reductions that the ACHD projects are needed for PM2.5 
attainment in the Liberty-Clairton Area by 2015 will come from a 
combination of upgrades and shutdowns of batteries and quench towers at 
the U.S. Steel Mon Valley Works Clairton (U.S. Steel) and Edgar Thomson 
Plants in response to a number of previous visible emissions and 
opacity violations. In accordance with a March 2008 consent order and 
agreement between ACHD and U.S. Steel, several upgrades and shutdowns 
have taken place or are required to take place, including:
    a. Batteries 7, 8, and 9 were permanently shut down on April 16, 
2009. The original date for shut down was December 31, 2012 in the 
consent order and agreement. The new Battery C will replace the 
production of Batteries 7, 8, and 9 at significantly lower emissions 
due to newer and cleaner technology. This project reduces emissions of 
direct PM2.5 by over 200 tons per year at a cost of $500 
million.
    b. 25 heating walls on Battery 19 will be replaced by October 31, 
2012. The battery will meet its opacity limits by December 31, 2012, 
including, as necessary, implementing an advanced patching plan.
    In September 2010, ACHD and U.S. Steel amended the March 2008 
consent order and agreement to include the construction of new low 
emission quench towers for Batteries 13-15 and Batteries 19-20 by 
December 31, 2013. The new quench towers 5A and 7A will be used as the 
primary quench towers for Batteries 13-15 and Batteries 19-20, 
respectively. The current quench towers 5 and 7 will serve as auxiliary 
quench towers. The new quench towers 5A and 7A will reduce emissions of 
direct PM2.5 by 593 tons per year.
    Additional reductions are achieved by a June 2007 ACHD and U.S. 
Steel consent decree to rebuild the B Battery heating walls, which was 
to be completed by June 30, 2010, and replacement of 25 heating walls 
on Battery 19 by October 2012 to meet opacity limits. Table 3 below 
summarizes the reductions that are relied on in the Liberty-Clairton 
Area PM2.5 attainment plan to demonstrate attainment by 
April 5, 2015.

       Table 3--Summary of Reductions Needed for the Liberty-Clairton Area PM2.5 Attainment Demonstration
                                                 [Tons per year]
----------------------------------------------------------------------------------------------------------------
                                                                   Direct PM2.5         NOX             SO2
----------------------------------------------------------------------------------------------------------------
A. 2002 emissions level.........................................         2,270.6       229,571.7       587,201.4
B. 2014 attainment target.......................................         1,392.6       108,565.5       132,598.7
C. Total reductions needed by 2014 (A minus B)..................           878.0       121,006.2       454,602.7
----------------------------------------------------------------------------------------------------------------

    The majority of direct PM2.5 emissions reductions that 
the State projects are needed for PM2.5 attainment in the 
Liberty-Clairton Area by 2015 come from the combination of upgrades and 
shutdowns of batteries and quenches towers at the U.S. Steel Mon Valley 
Clairton Plant. ACHD included in this table the reductions of 
PM2.5 precursor pollutants NOX and SO2 
that are achieved by the regional programs that address transported 
emissions. The NOX and SO2 projected reductions 
shown in this table come from the CAIR regional trading program, and 
are addressed in the regional modeling discussed below. The sources 
from which these NOX and SO2 emission reductions 
are achieved are located upwind of the Liberty-Clairton Area in the 
Pittsburgh Area.
4. 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 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 defines RACM as measures that a state finds 
are both reasonably available and contribute to attainment as 
expeditiously as practicable in its nonattainment area. Thus, what 
constitutes RACM/RACT in a PM2.5 attainment plan is closely 
tied to that plan's expeditious attainment demonstration. See, 40 CFR 
51.1010 and 72 FR 20586 at 20612. States are required to evaluate RACM/
RACT for direct PM2.5 and all of its attainment plan 
precursors. See, 40 CFR 51.1002(c).
    Consistent with subpart 1 of Part D of the CAA, EPA is requiring a 
combined approach to RACM and RACT for PM2.5 attainment 
plans. Subpart 1, unlike

[[Page 68704]]

subparts 2 and 4, does not identify specific source categories for 
which EPA must issue control technology documents or guidelines for 
what constitutes RACT, or identify specific source categories for state 
and EPA evaluation during attainment plan development. See, 72 FR 20586 
at 20610. Rather, under subpart 1, EPA considers RACT to be part of an 
area's overall RACM obligation. Because of the variable nature of the 
PM2.5 problem in different nonattainment areas, EPA 
determined not only that states should have flexibility with respect to 
RACT and RACM controls, but also that in areas needing significant 
emission reductions to attain the standards, RACT/RACM controls on 
smaller sources may be necessary to reach attainment as expeditiously 
as practicable. See, 72 FR 20586 at 20612, 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 and 72 FR 20586 at 20612.
    The PM2.5 Implementation Rule requires that attainment 
plans include the list of measures a state considered and information 
sufficient to show that the state met all requirements for the 
determination of what constitutes RACM/RACT in its specific 
nonattainment area. See, 40 CFR 51.1010. 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. 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 at 
20614.
    ACHD undertook a process to identify and evaluate potential 
reasonably available control measures that could contribute to 
expeditious attainment of the PM2.5 standard for the 
Liberty-Clairton Area. These RACM/RACT analyses address control 
measures for sources of direct PM2.5 only. The control 
measures for sources of SO2 or NOX were not 
addressed because, as explained earlier, the area is too small and 
conditions are not appropriate for SO2 or NOX 
from sources located within the nonattainment area to be able to 
convert to PM2.5. ACHD's RACM/RACT analysis focused on 
point, area and mobile source controls. To identify potential RACM/RACT 
in the 12 square kilometer nonattainment area, ACDH's review of 
potential measures from two major sources (U.S. Steel Clairton Plant 
and Koppers Industries, Inc. Clairton Plant), and one minor source (Mid 
Continent Coal and Coke Company) is summarized below.
    For the U.S. Steel Clairton Plant, many alternatives were 
considered for the coke batteries and quench towers. For the Coke 
batteries, there were very few alternatives were available, since some 
of the nation's strictest standards are already in place for this 
facility. Of the alternatives considered, none were considered 
technically feasible for integration into the process. For the quench 
towers, among the many alternatives considered were short towers with 
single baffles, wet low emission quench, coke stabilization quenching 
process, and Kress indirect cooling system. However, they were all 
found to be unacceptable due to the cost effectiveness, potential 
magnitude and timing of emissions reductions and availability of space. 
For the Koppers Industries Inc. Clairton Plant, alternatives were 
considered for the tar refining process and the manufacturing of the 
rod pitch. For both the tar refining process and manufacturing of the 
rod pitch, the alternatives considered resulted in no additional 
emissions reductions. For the Mid Continent Coal and Coke Company, the 
total PM2.5 emissions are no more than five tons per year, 
mostly resulting from unpaved roads. The emission reductions benefit 
from the implementation of dust suppressants would produce only 
insignificant emission reductions and would not advance the attainment 
date by one year or more even if combined with other control measures. 
After completing its RACM/RACT analysis for stationary, area and mobile 
sources of direct PM2.5, ACHD concluded that no additional 
reasonable controls are available that would advance the attainment 
date by one year.
    Based on our review of potential RACM/RACT in the Liberty-Clairton 
Area PM2.5 attainment plan, we agree that there are no 
additional reasonably available control measures that individually, or 
collectively, would advance attainment of the 1997 PM2.5 
NAAQS in the Liberty-Clairton nonattainment area by one year or more, 
and propose to approve the RACM/RACT determination submitted by PADEP.
5. Modeling
    The PM2.5 Implementation Rule requires states to submit 
an attainment demonstration based on modeling results. Specifically, 40 
CFR 51.1007(a) states that for any area designated as nonattainment for 
the PM2.5 NAAQS, the state must submit an attainment 
demonstration showing that the area will attain the annual and 24-hour 
standards as expeditiously as practicable. The demonstration must meet 
the requirements of 40 CFR part 51 and appendix W of this part and must 
include inventory data, modeling results, and emission reduction 
analyses on which the state has based its projected attainment date. 
The attainment date justified by the demonstration must be consistent 
with the requirements of 40 CFR 51.1004(a). The modeled strategies must 
be consistent with requirements in 40 CFR 51.1009 for RFP and in 40 CFR 
51.1010 for RACT and RACM. The attainment demonstration and supporting 
air quality modeling should be consistent with EPA's PM2.5 
modeling guidance.\2\ See also, 72 FR 20586 at 20665.
---------------------------------------------------------------------------

    \2\ EPA's modeling guidance can be found in ``Guideline on Air 
Quality Models'' in 40 CFR part 51, appendix W and ``Guidance on the 
Use of Models and Other Analyses for Demonstrating Attainment of Air 
Quality Goals for the 8-Hour Ozone and PM2.5 NAAQS and 
Regional Haze,'' EPA-454/B-07-002, April 2007.
---------------------------------------------------------------------------

    Air quality modeling is used to establish emissions attainment 
targets, the combination of emissions of PM2.5 and 
PM2.5 precursors that the area can accommodate without 
exceeding the NAAQS and to assess whether the proposed control strategy 
will result in attainment of the NAAQS. Air quality modeling is 
performed for a base year and compared to air quality monitoring data 
in order to evaluate model performance. Once the performance is 
determined to be acceptable, future year changes to the emissions 
inventory are simulated to determine the relationship between emissions 
reductions and changes in ambient air quality throughout the air basin.
    The procedures for modeling PM2.5 as part of an 
attainment SIP are contained in EPA's ``Guidance on the Use of Models 
and Other Analyses for Demonstrating Attainment of Air Quality Goals 
for the 8-Hour Ozone and PM2.5 NAAQS and Regional Haze.'' 
This guidance encourages states to take a nine-step approach when 
preparing a modeling analysis to demonstrate attainment of the 
PM2.5 NAAQS. The nine steps include formulation of a 
conceptual description of the nonattainment problem, development of a 
modeling protocol, use of an

[[Page 68705]]

appropriate model using appropriate meteorological episodes and a 
modeling domain to establish initial and boundary conditions, 
generation of meteorological and air quality inputs, generation of 
emissions inputs, evaluation of the performance of the air quality 
model, and performance of future year modeling that includes control 
strategies, followed by application of the attainment test.
    ACHD's conceptual description of its PM2.5 nonattainment 
problem is provided in Appendix C (Modeling Protocol) of its attainment 
SIP. The unique meteorologic and geologic features of the area was also 
discussed briefly in section A.3 of this notice. Episodes of poor air 
quality often occur within the Liberty-Clairton Area during periods of 
strong nocturnal inversions. When this occurs, air dispersion is often 
minimized, allowing emissions to ``build up'' within the river valleys, 
and contributing to episodes of poor air quality that leads to high 
PM2.5 design values. Many times, PM2.5 
concentrations in the Liberty-Clairton Area are significantly higher 
than concentrations in the nearby city of Pittsburgh. Using source 
apportionment modeling for the Liberty and Lawrenceville monitors in 
Allegheny County, ACHD's analysis found that the Liberty monitor's 
PM2.5 concentrations are impacted by regional loading based 
on similarities in both monitor's speciation data and that sources near 
the Liberty monitor are responsible for the speciation differences 
observed between the two monitors.
    The Liberty-Clairton PM2.5 SIP utilized two components 
in its attainment demonstration modeling: a regional photochemical grid 
model and a local scale model with sufficient resolution to examine the 
impacts of local emission sources. Model results were used in a 
relative rather than an absolute sense. Following this methodology, the 
ratio of the model's future to current (baseline) predictions at both 
of the nonattainment area's PM2.5 monitors determines if the 
controls in the Liberty-Clairton Area are likely to lead to attainment 
with the 1997 p.m.2.5 NAAQS.
    The regional modeling demonstration for the Liberty-Clairton Area 
used the Community Multiscale Air Quality (CMAQ) model. The CMAQ 
modeling was performed by the Bureau of Air Quality Analysis and 
Research, New York State Department of Environmental Conservation (DEC) 
using Mid-Atlantic/Northeast Visibility Union Regional Planning 
Organization (MANE-VU) inventory with a base year of 2002. Regional 
controls for SO2 and NOX in the MANE-VU inventory 
were based on the CAIR. Local sources in the Liberty-Clairton Area 
create steep gradients in PM2.5 concentrations than cannot 
be adequately resolved by the CMAQ model, which uses grid cells that 
are roughly 12 square kilometers--approximately the total area of the 
Liberty-Clairton Area. Local scale meteorology is also not well 
simulated by the CMAQ model due to steep topography within the Liberty-
Clairton Area that often contributes to strong temperature inversions 
and complex flow patterns within the valleys. ACHD's analysis of its 
PM2.5 monitors within Allegheny County showed significant 
local impacts at the Liberty-Clairton Area. To better simulate the 
local source impacts within the nonattainment area, ACHD used the 
California PUFF (CALPUFF) air quality dispersion modeling system.
    The CALPUFF modeling system uses CALMET, a diagnostic 3-dimensional 
meteorological model, and CALPOST, a post processing program. The 
CALPUFF model, which uses a much finer scale than the regional model, 
was used to help better resolve local topographic features that 
influence emission dispersion and address spatial relationships between 
local sources and the monitors in the Liberty-Clairton Area. The 
CALPUFF grid spacing for the 150 km regional source analysis domain was 
one kilometer and 100 meters for the 20 kilometer local scale analysis 
domain. The CALMET processor was used to recreate some of the more 
complex atmospheric flows in the Liberty-Clairton Area.
    The MANE-VU regional analysis used northeastern United States 
emissions inventories for all source classifications. The year 2002 was 
used for the baseline emissions inventory and 2014 for the projected 
inventory for the Liberty-Clairton Area. Regional projections used on-
the-books/on-the-way (OTB/OTW) controls through the 2012 timeframe. 
Since no additional projections were available at the time, and since 
Liberty-Clairton controls focus on direct PM2.5 emissions, 
the inventory was limited to direct PM2.5 emissions and was 
developed from both the regional MANE-VU projections for 2012 for 
precursors and non-point PM2.5 emissions in combination with 
ACHD's local projections for 2014 for stationary point PM2.5 
emissions. A more detailed inventory, limited to PM2.5, was 
developed by the ACHD for the extended Liberty-Clairton Area as part of 
its CALPUFF modeling analysis. This inventory was developed from both 
the MANE-VU inventories and projections, which were based on CAIR, 
along with ADCH's inventories for stationary point sources.
    The monitored attainment test for PM2.5 utilizes both 
PM2.5 and individual PM2.5 component species. The 
attainment test for PM2.5 is the Speciated Modeled 
Attainment Test (SMAT). In SMAT, a separate relative response factor 
(RRF) is calculated for each PM2.5 component. These RRF 
values are then multiplied by the base year concentrations for each 
monitor within the nonattainment area to determine if an area is 
projected to attain the NAAQS.
    The Liberty-Clairton Area has two PM2.5 monitoring 
sites, the Liberty monitor and the Clairton monitor. Speciation data 
from the Liberty monitor was used for the Clairton monitor since this 
site does not collect speciation data. Annual and 24-hour 
PM2.5 concentrations for both the Liberty and Clairton 
monitors were calculated from the quarterly base-year averaged monitor 
concentrations and the RRFs calculated from THE CMAQ MODEL and CALPUFF 
for each PM2.5 component. Results for the annual and 24-hour 
PM2.5 NAAQS are summarized in Table 4 which shows that the 
projected 2014 annual and 24-hour design values for the 1997 
PM2.5 NAAQS.

                                      Table 4--Modeled PM2.5 Design Values
----------------------------------------------------------------------------------------------------------------
                                              Annual standard                        24-Hour standard
             Monitor             -------------------------------------------------------------------------------
                                    2014 Projected        1997 NAAQS        2014 Projected        1997 NAAQS
----------------------------------------------------------------------------------------------------------------
Liberty.........................  14.3 [mu]g/m\3\...  15.0 [mu]g/m\3\...  42 [mu]g/m\3\.....  65 [mu]g/m\3\.
Clairton........................  11.8 [mu]g/m\3\...  15.0 [mu]g/m\3\...  27 [mu]g/m\3\.....  65 [mu]g/m\3\.
----------------------------------------------------------------------------------------------------------------


[[Page 68706]]

    EPA's modeling guidance states that additional analyses are 
recommended to determine if attainment will be likely, even if the 
modeled attainment test is ``passed.'' The guidance recommends 
supplementary analyses in all cases. EPA's modeling guidance describes 
how to use a photochemical grid model and additional analytical methods 
to complete a weight of evidence (WOE) analysis to estimate if 
emissions control strategies will lead to attainment. A WOE analysis is 
a supporting analysis that helps to determine if the results of the 
photochemical modeling system are, or are not, correctly predicting 
future air quality.
    All models, including the CMAQ model, have inherent uncertainties. 
Over or under prediction may result from uncertainties associated with 
emission inventories, meteorological data, and representation of 
PM2.5 chemistry in the model. Therefore, EPA modeling 
guidance provides for the consideration of other evidence to address 
these model uncertainties so that proper assessment of the probability 
to attain the applicable standards can be made. EPA modeling guidance 
states that those modeling analyses that show that attainment with the 
NAAQS will be reached in the future with some margin of safety (i.e., 
estimated concentrations below 14.5 [mu]g/m\3\ for annual 
PM2.5 and 62 [mu]g/m\3\ for 24-hour PM2.5) need 
more limited supporting material.
    Due to the fact that the modeling results presented in Table 4 fall 
below the aforementioned ``weight of evidence'' thresholds established 
by EPA, a limited supplemental analysis was deemed necessary to support 
the 2014 attainment demonstration. ACHD provided a WOE demonstration 
that consisted of an analysis of monitor trends, local and national 
emission control programs, population trends and monitoring 
concentrations during periods of low production. ACHD included a 
summary of various local and regional emission control programs being 
implemented in the Area, although some of these control measures may 
extend beyond the Liberty-Clairton Area and therefore, may have a 
lesser impact. Emission control programs used for WOE include 
Pennsylvania's wood boiler regulation, a wood stove change out program 
in southwest Pennsylvania, EPA's CSAPR as it was proposed, Allegheny 
County's diesel fuel engine retrofit program, local and state anti-
idling campaigns and Allegheny County's program to reduce diesel 
particulate emissions. The additional reductions from these programs 
were used as further evidence supporting ACHD's conclusion that its SIP 
modeling demonstrates compliance with the 1997 PM2.5 NAAQS.
    Based on the technical information provided in the Liberty-Clairton 
Area attainment demonstration SIP revision, EPA concludes that the 
modeling and WOE analyses demonstrate attainment of the 1997 
PM2.5 NAAQS by the attainment date proposed as part of this 
notice (April 5, 2015). The demonstration shows that the Liberty-
Clairton Area will attain the 1997 annual PM2.5 NAAQS by 
2015, which is as expeditiously as practical considering the area's 
elevated 2002 base year design values of 21.4 [mu]g/m\3\ for the annual 
NAAQS and 63 [mu]g/m\3\ for the 24-hour NAAQs at the Liberty monitor 
and the reasonably available control measures discussed above. ACHD's 
modeled 2014 design values for the Annual PM2.5 NAAQS and 
the 24-Hour PM2.5 NAAQS are expected to be below 15.0 [mu]g/
m\3\ and 65 [mu]g/m\3\, respectively, indicating the nonattainment area 
satisfies the CAA requirement that SIPs provide for attainment of the 
NAAQS by the applicable attainment date.
    However, because the regional CMAQ modeling relied upon EPA's CAIR 
program, EPA is requiring ACHD to provide an additional analysis to 
confirm model results, in light of EPA's promulgation of CSAPR on 
August 8, 2011 (76 FR 48208), to replace the remanded CAIR rule. While 
ACHD's SIP submittal predated EPA's promulgation of CSAPR, to ensure 
that the modeling demonstration is still valid, ACHD must update the 
analysis it included in section 13.3 of its attainment plan to include 
CSAPR instead of CAIR, and review and update, if appropriate, its 
modeling technical support document (TSD). To ensure that the analysis 
in the June 17, 2011 submittal is valid during the implementation of 
CSAPR, the results, with CSAPR, must show at least the same 
concentrations that resulted from the modeling demonstration with CAIR. 
EPA is, therefore, conditionally approving the modeling portion of the 
Liberty-Clairton Area attainment demonstration SIP. Final approval of 
the modeling demonstration portion of the SIP is contingent on ACHD's 
reanalysis of the elements included in section 13.3 of its attainment 
demonstration and the associated TSD to show that implementation of 
CSAPR provides at least equivalent model concentrations in the Liberty-
Clairton Area as was shown in its June 17, 2011 submittal.
    More detailed information about the modeling and our evaluation are 
available in the modeling TSD available in the docket for this 
rulemaking.
6. Determination of the Attainment Date
    CAA Section 172(a)(2) provides that an area's attainment date 
``shall be the date by which attainment can be achieved as 
expeditiously as practicable, but no later than five years from the 
date such area was designated nonattainment, except that the 
Administrator may extend the attainment date to the extent the 
Administrator determines appropriate, for a period no greater than 10 
years from the date of designation as nonattainment considering the 
severity of nonattainment and the availability and feasibility of 
pollution control measures.'' Because the effective date of 
designations for the 1997 PM2.5 NAAQS is April 5, 2005 (See 
70 FR 944), the initial attainment date for PM2.5 
nonattainment areas is as expeditiously as practicable, but not later 
than April 5, 2010. For any area that is granted a full five-year 
attainment date extension under CAA section 172, the attainment date 
would be not later than April 5, 2015. Section 51.1004 of the 
PM2.5 Implementation Rule addresses the attainment date 
requirement. Section 51.1004(b) requires a state to submit an 
attainment demonstration justifying its proposed attainment date and 
provides that EPA will approve an attainment date when we approve that 
demonstration.
    States that request an extension of the attainment date under CAA 
section 172(a)(2) must provide sufficient information to show that 
attainment by April 5, 2010 is impracticable due to the severity of the 
nonattainment problem in the area and the lack of available and 
feasible control measures to provide for earlier attainment. See, 40 
CFR 51.1004(b). States must also demonstrate that all RACM and RACT for 
the area are being implemented to bring about attainment of the 
standard by the most expeditious alternative date practicable for the 
area. See, 72 FR 20586 at 20601.
    In the course of evaluating whether the attainment date for the 
Liberty-Clairton Area should be extended, EPA has considered several 
factors. First, EPA has considered the technical basis supporting the 
attainment demonstration, including whether the emissions inventories 
and air quality modeling, are adequate. As discussed previously, EPA is 
proposing to approve the emissions inventories and conditionally 
approve the air quality modeling on which the Liberty-Clairton 1997 
PM2.5 attainment demonstration and other provisions are 
based. Second, EPA has considered whether the SIP submittal provides 
for expeditious

[[Page 68707]]

attainment through the implementation of all RACM and RACT. As 
discussed in section A.4, EPA is proposing to approve the RACM/RACT 
demonstration in the Liberty-Clairton PM2.5 attainment 
demonstration. Third, EPA has considered whether the emissions 
reductions that are relied on for attainment are creditable. As 
discussed in section A.3, the Liberty-Clairton Area attainment 
demonstration relies on upgrades and shutdowns at the U.S. Steel Plant 
for reductions of PM2.5, and regional reduction programs to 
achieve NOX and SO2 reductions, that are needed 
to attain the 1997 PM2.5 standards in the Liberty-Clairton 
Area by April 5, 2015. Finally, EPA must determine whether the 
attainment demonstration provides sufficient information to show that 
attainment by April 5, 2010 is impracticable due to the severity of the 
nonattainment problem in the area and the lack of available and 
feasible control measures to provide for earlier attainment. See, 40 
CFR 51.1004(b).
    The Liberty-Clairton Area SIP submittal provides sufficient 
information to show that attainment by April 5, 2010 is impracticable 
due to the severity of the nonattainment problem in the area and the 
lack of available and feasible control measures to provide for earlier 
attainment. In particular, this submission includes sufficient modeling 
data to support a finding that the attainment date for the Liberty-
Clairton Area should be April 5, 2015, and that the area qualifies for 
the full five-year extension of the attainment date allowable under 
section 172(a)(1). Furthermore, the SIP submittal provides for 
expeditious implementation of the available control programs. The 
implementation schedule for the controls is expeditious, while taking 
into account the time necessary for purchase and installation of the 
required control technologies.
    Based upon the above considerations, EPA is proposing to determine 
that a five-year extension of the attainment date is appropriate given 
the severity of the nonattainment problem in the Liberty-Clairton Area, 
and the unavailability and infeasibility of additional control measures 
and, therefore, EPA is proposing to extend the attainment date in the 
Liberty-Clairton Area to April 5, 2015.
7. RFP
    CAA section 172(c)(2) requires that plans for nonattainment areas 
shall provide for RFP. RFP is defined in section 171(1) as ``such 
annual incremental reductions in emissions of the relevant air 
pollutant as are required by this part or may reasonably be required by 
the Administrator for the purpose of ensuring