Document ID: EPA-R03-OAR-2017-0615-0035
Agency: epa
Document Type: Proposed Rule
Title: Air Quality State Implementation Plans; Approval and Promulgation: Supplemental Information and Data for the Indiana, Pennsylvania Nonattainment Area for the 2010 Sulfur Dioxide Primary National Ambient Air Quality Standard
Posted Date: 2020-03-09T04:00Z

[Federal Register Volume 85, Number 46 (Monday, March 9, 2020)]
[Proposed Rules]
[Pages 13602-13603]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2020-04774]

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 52

[EPA-R03-OAR-2017-0615; FRL-10006-16-Region 3]

Supplemental Information and Data for the Indiana, Pennsylvania 
Nonattainment Area for the 2010 Sulfur Dioxide Primary National Ambient 
Air Quality Standard; Notice of Data Availability (NODA)

AGENCY: Environmental Protection Agency (EPA).

ACTION: Notice of data availability; request for public comment.

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SUMMARY: The Environmental Protection Agency (EPA) is announcing the 
availability of new modeling, meteorological and emissions information 
and data contained in a package submitted to EPA by the Commonwealth of 
Pennsylvania on February 5, 2020 in support of the Indiana, 
Pennsylvania state implementation plan (SIP, or Attainment Plan) for 
the 2010 sulfur dioxide (SO2) primary National Ambient Air 
Quality Standard (NAAQS). EPA will be evaluating this information as 
well as any public comments received to take final action on the 
Attainment Plan. The modeling and large data files submitted are not 
provided in the docket but are available upon request by contacting the 
person named in the FOR FURTHER INFORMATION CONTACT section.

DATES: Written comments must be received on or before April 8, 2020.

ADDRESSES: Submit your comments, identified by Docket ID No. EPA-R03-
OAR-2017-0615 at https://www.regulations.gov, or via email to 
spielberger.susan@epa.gov. For comments submitted at Regulations.gov, 
follow the online instructions for submitting comments. Once submitted, 
comments cannot be edited or removed from Regulations.gov. For either 
manner of submission, EPA may publish any comment received to its 
public docket. Do not submit electronically any information you 
consider to be confidential business information (CBI) or other 
information whose disclosure is restricted by statute. Multimedia 
submissions (audio, video, etc.) must be accompanied by a written 
comment. The written comment is considered the official comment and 
should include discussion of all points you wish to make. EPA will 
generally not consider comments or comment contents located outside of 
the primary submission (i.e., on the web, cloud, or other file sharing 
system). For additional submission

[[Page 13603]]

methods, please contact the person identified in the FOR FURTHER 
INFORMATION CONTACT section. For the full EPA public comment policy, 
information about CBI or multimedia submissions, and general guidance 
on making effective comments, please visit http://www2.epa.gov/dockets/commenting-epa-dockets.

FOR FURTHER INFORMATION CONTACT: Megan Goold, Planning & Implementation 
Branch (3AD30), Air & Radiation Division, U.S. Environmental Protection 
Agency, Region III, 1650 Arch Street, Philadelphia, Pennsylvania 19103. 
The telephone number is (215) 814-2027. Ms. Goold can also be reached 
via electronic mail at goold.megan@epa.gov.

SUPPLEMENTARY INFORMATION: 

I. General Information

    EPA proposed approval of the Attainment Plan for the Indiana, 
Pennsylvania Nonattainment Area for the 2010 SO2 NAAQS on 
July 13, 2018. 83 FR 32606. As part of approving the Attainment Plan, 
EPA also proposed to approve into the Pennsylvania SIP SO2 
emission limits and associated compliance parameters for Keystone, 
Conemaugh, Homer City and Seward Generating Stations. The public 
comment period for EPA's proposal closed on August 13, 2018. During the 
public comment period, EPA received from one commenter new information 
and analysis purporting to show that, using an alternative receptor 
grid, the critical emission values (CEVs) for Seward and Conemaugh 
Stations modeled a violation of the standard within the boundaries of 
the nonattainment area (NAA). In response, the Pennsylvania Department 
of Environmental Protection (PADEP) opted to provide EPA with 
supplemental information to provide further support for their submitted 
Attainment Plan. The supplemental information includes: (1) A 
supplemental air dispersion modeling report, (2) Supplemental air 
dispersion modeling data, (3) Supplemental air dispersion modeling 
protocol, (4) A meteorological monitoring plan, (5) Meteorological 
monitoring data, (6) Meteorological monitoring quality assurance, 
quality control, and audit reports, (7) Clean Air Markets Division 
(CAMD) emission data for 2010-2018, and (8) Continuous Emissions 
Monitoring (CEM) data for 2010-2019 (3rd Quarter).
    PADEP's supplemental modeling report provides additional modeling 
using the newly provided site specific meteorological data to support 
the SO2 emission limits established in the original 
attainment plan. The study supplements the modeling submitted in 2017 
(see Docket EPA-R03-OAR-2017-0615-0018 which can be located via https://www.regulations.gov) to focus on the area in the NAA near Conemaugh 
and Seward stations. The meteorological data collection spanned the 13-
month period of August 1, 2015 through August 31, 2016. Due to better 
SOnic Detection And Radar (SODAR) data capture percentages for the 
September 1, 2015 through August 31, 2016 period, this 12-month period 
was used for this supplemental modeling analysis. PADEP used AERMOD 
dispersion model 16 (Version 19191), current as of August 2019, to 
evaluate air quality impacts from the emission sources of interest. The 
South Fayette, Pennsylvania monitor, which is located about 62 
kilometers to the west-southwest of the Indiana County NAA, was used to 
determine the uniform regional background component for the NAAQS 
SO2 modeling. The most recent 3-year period (2016-2018) of 
emissions data were used in the modeling analysis and details on the 
emissions processing are provided in the submittal, which can be found 
in the docket for this notice.
    The modeling was used to define CEVs for Seward and Conemaugh 
Generating Stations that show 99th percentile peak daily 1-hour maximum 
concentrations (``design concentrations'') complying with the 1-hour 
SO2 NAAQS. For the Seward and Conemaugh Generating Stations, 
longer-term emission rates that are discounted from the 1-hour CEV 
rates were derived. Different averaging times were selected to best fit 
the emission source profiles at each plant. Conemaugh emission rates 
are based upon a 3-hour block emission average, and the Seward emission 
rate is based upon a rolling 30-day average. The current SO2 
emission limits for the modeled emission sources at the Conemaugh and 
Seward Stations are lower than the longer-term emission rates that 
demonstrate attainment with the NAAQS through modeling.
    To demonstrate that Seward's rolling 30-day emission limit is 
protective of the NAAQS, PADEP submitted randomly reassigned emissions 
(RRE) modeling. One hundred AERMOD simulations were run using randomly 
reassigned 1-hour emission rates for Seward's emissions along with 
constant CEV 1-hour emission rates for the remaining three 
SO2 sources in the NAA plus regional background (South 
Fayette monitor for 2016-2018 as discussed in Section 4.7 of the 
Modeling Report). For each of the 100 modeling runs with one year of 
on-site meteorology, the 99th percentile peak daily 1-hour maximum at 
each receptor resulted in design concentrations that comply with the 
NAAQS. The highest 99th percentile daily maximum SO2 
concentration of the 100 model simulations was 190.05 micrograms per 
meter cubed ([mu]g/m \3\) (this occurred in simulation run 44) and is 
less than the NAAQS (196.4 [mu]g/m \3\).
    The supplemental modeling purports to demonstrate that a lower CEV 
for Seward Generating Station demonstrates attainment compared to the 
CEV provided in the original attainment plan. The rolling 30-day 
emission limit for Seward has remained unchanged. The newly submitted 
RRE modeling purportedly demonstrates that the rolling 30-day emission 
limit for Seward is protective of the NAAQS. The CEV for Conemaugh 
Generating Station has not changed from the original Attainment Plan as 
a result of the supplemental modeling analysis, and therefore no 
additional analysis was provided in support of the source's longer term 
3-hour block limit.
    EPA is seeking comment on the Pennsylvania supplemental information 
submitted on February 5, 2020 as supporting analysis that shows the 
previously-established longer term emission limits for Seward and 
Conemaugh Generating Stations demonstrate attainment of the 2010 
SO2 NAAQS in the Nonattainment Area. EPA is not seeking 
comment on any other aspect of the Attainment Plan, which has already 
gone through the public comment process from July 13, 2018 through 
August 13, 2018.

    Dated: February 24, 2020.
Cosmo Servidio,
Regional Administrator, Region III.
[FR Doc. 2020-04774 Filed 3-6-20; 8:45 am]
 BILLING CODE 6560-50-P