Document ID: EPA-R08-OAR-2010-0285-0043
Agency: epa
Document Type: Proposed Rule
Title: Attainment Demonstrations for 1997 8-Hour Ozone Standard and Related Revisions: Denver Metro Area/North Front Range, CO
Posted Date: 2010-12-17T05:00Z

[Federal Register Volume 75, Number 242 (Friday, December 17, 2010)]
[Proposed Rules]
[Pages 78950-78952]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2010-31738]

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 52

[EPA-R08-OAR-2010-0285; FRL-9239-9]

Availability of Additional Information for the Proposed 
Rulemaking for Colorado's Attainment Demonstration for the 1997 8-Hour 
Ozone Standard and Related Revisions

AGENCY: Environmental Protection Agency (EPA).

[[Page 78951]]

ACTION: Notice of data availability.

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SUMMARY: This document announces the availability of revised modeling 
that relates to EPA's notice of proposed rulemaking for Colorado's 
Attainment Demonstration for the 1997 8-hour Ozone Standard for the 
Denver Metro Area/North Front Range (DMA/NFR) nonattainment area and 
Related Revisions. The results of the modeling and the modeling files 
have been placed in the docket for this rulemaking. EPA is providing an 
opportunity to comment on the revised modeling.

DATES: Comments must be received on or before January 18, 2011.

ADDRESSES: Submit your comments identified by Docket ID Regulation 
Number EPA-R08-OAR-2010-0285 by one of the following methods:
     Mail: Callie Videtich, Director, Air Program, 
Environmental Protection Agency (EPA), Region 8, Mailcode 8P-AR, 1595 
Wynkoop Street, Denver, Colorado 80202-1129.
     Hand Delivery: Callie Videtich, Director, Air Program, 
Environmental Protection Agency (EPA), Region 8, Mailcode 8P-AR, 1595 
Wynkoop Street, Denver, Colorado 80202-1129. Such deliveries are only 
accepted Monday through Friday, 8 a.m. to 4:30 p.m., excluding Federal 
holidays. Special arrangements should be made for deliveries of boxed 
information.
     E-mail: komp.mark@epa.gov.
     Fax: (303) 312-6064 (please alert the individual listed in 
the FOR FURTHER INFORMATION CONTACT if you are faxing comments).
    Instructions: Direct your comments to Docket ID No. EPA-R08-OAR-
2010-0285. EPA's policy is that all comments received will be included 
in the public docket without change and may be made available online at 
http://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 http://www.regulations.gov or e-mail. The http://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 e-mail comment directly to EPA, without 
going through http://www.regulations.gov your e-mail 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 instructions on submitting 
comments, go to Section I. General Information of the SUPPLEMENTARY 
INFORMATION section of this document.
    Docket: All documents in the docket are listed in the http://www.regulations.gov index. Although listed in the index, some 
information is not publicly available, e.g., CBI or other information 
whose disclosure is restricted by statute. Certain other material, such 
as copyrighted material, will be publicly available only in hard copy. 
Publicly available docket materials are available either electronically 
in http://www.regulations.gov or in hard copy at the Air Program, 
Environmental Protection Agency (EPA), Region 8, 1595 Wynkoop Street, 
Denver, Colorado 80202-1129. EPA requests that if at all possible, you 
contact the individual listed in the FOR FURTHER INFORMATION CONTACT 
section to view the hard copy of the docket. You may view the hard copy 
of the docket Monday through Friday, 8 a.m. to 4 p.m., excluding 
Federal holidays.

FOR FURTHER INFORMATION CONTACT: Mark Komp, Air Program, 1595 Wynkoop 
Street, Mailcode: 8P-AR, Denver, Colorado 80202-1129, (303) 312-6022, 
komp.mark@epa.gov.

SUPPLEMENTARY INFORMATION:

Table of Contents

I. General Information
II. Notice of Data Availability

Definitions

    For the purpose of this document, the following definitions apply:
    (i) Act or CAA means or refers to the Clean Air Act, unless the 
context indicates otherwise.
    (ii) EPA, we, us or our means or refers to the United States 
Environmental Protection Agency.
    (iii) SIP means or refers to State Implementation Plan.
    (iv) ppb means parts per billion of ozone in air.
    (v) State or Colorado means the State of Colorado, unless the 
context indicates otherwise.
    (vi) NAAQS means or refers to National Ambient Air Quality 
Standards.
    (vii) NODA means or refers to Notice of Data Availability.

I. General Information

A. What should I consider as I prepare my comments for EPA?

    1. Submitting CBI. Do not submit this information to EPA through 
http://regulations.gov or e-mail. Clearly mark the part or all of the 
information that you claim to be CBI. For CBI information in a disk or 
CD-ROM that you mail to EPA, mark the outside of the disk or CD-ROM as 
CBI and then identify electronically within the disk or CD-ROM the 
specific information that is claimed as CBI. In addition to one 
complete version of the comment that includes information claimed as 
CBI, a copy of the comment that does not contain the information 
claimed as CBI must be submitted for inclusion in the public docket. 
Information so marked will not be disclosed except in accordance with 
procedures set forth in 40 CFR part 2.
    2. Tips for Preparing Your Comments. When submitting comments, 
remember to:
     Identify the rulemaking by docket number and other 
identifying information (subject heading, Federal Register date and 
page number).
     Follow directions--The agency may ask you to respond to 
specific questions or organize comments by referencing a Code of 
Federal Regulations (CFR) part or section number.
     Explain why you agree or disagree; suggest alternatives 
and substitute language for your requested changes.
     Describe any assumptions and provide any technical 
information and/or data that you used.
     If you estimate potential costs or burdens, explain how 
you arrived at your estimate in sufficient detail to allow for it to be 
reproduced.
     Provide specific examples to illustrate your concerns, and 
suggest alternatives.
     Explain your views as clearly as possible, avoiding the 
use of profanity or personal threats.
     Make sure to submit your comments by the comment period 
deadline identified.

II. Notice of Data Availability

    On June 18, 2009, Colorado submitted revisions to the Colorado SIP 
for the 1997 8-hour ozone NAAQS for the DMA/NFR nonattainment area. The 
revisions included a modeled attainment demonstration using

[[Page 78952]]

photochemical grid modeling that the State conducted in 2008. 
(Photochemical grid modeling is used to project future 8-hour ozone 
Design Values for comparison to the 85.0 ppb ozone NAAQS.) On July 21, 
2010, we proposed to act on the State's revisions and as part of that 
action, proposed to approve Colorado's attainment demonstration and 
certain other aspects of the revisions, and proposed to disapprove 
other aspects of the revisions. For further information on Colorado's 
submittal and our proposed action, please consult the Federal Register 
(July 21, 2010; 75 FR 42346).
    On October 7, 2010, Colorado submitted revised photochemical 
modeling results to us for the DMA/NFR ozone SIP. Colorado re-ran the 
photochemical model because in September 2010 the State discovered that 
errors had been made in specifying the location of certain point 
sources in the 2008 modeling. Latitude/longitude locations for some 
point sources in the original modeling effort were mistakenly derived 
using the degree-minute-second coordinate system rather than the 
correct decimal degree coordinate system. As a result, some point 
source locations were displaced in the grid-coordinate system used by 
the model. Thus, Colorado re-ran the model with the correct coordinates 
to determine whether the errors made in locating some point sources 
affected the reliability of the model results.
    The projected Design Values for 2010 resulting from the revised 
modeling remain below the 85.0 ppb ozone NAAQS. For the SIP's 2010 base 
case, the revised modeling's maximum projected 8-hour ozone Design 
Values are found at the Rocky Flats North and Fort Collins West 
monitoring sites--84.7 ppb ozone at both locations in 2010. This is 0.2 
ppb lower than the State's 2008 modeling projected using incorrect 
point source locations. Because it produced slightly lower values at 
the monitoring sites with maximum Design Values, the revised modeling 
supports the conclusions that EPA proposed regarding the 2008 modeling.
    With this Notice of Data Availability, we are providing an 
opportunity for the public to comment on Colorado's October 2010 
revised modeling, including comments on how it may affect EPA's 
proposed determinations as reflected in our July 21, 2010 proposal. We 
are not re-opening the comment period on the material that was before 
the Agency at the time of the July 21, 2010 proposal.
    Colorado's October 2010 revised modeling is reflected in the 
following two documents, which we have added to the rulemaking docket:

    1. Final 2010 Ozone Attainment Demonstration Modeling for the 
Denver 8-Hour Ozone State Implementation Plan. Docket Number: EPA-
R08-OAR-2010-0285-0025.
    2. MEMORANDUM, October 7, 2010: ENVIRON: Denver Final 2010 Ozone 
Attainment Demonstration Modeling using Correct Point Source 
Locations. Docket Number: EPA-R08-OAR-2010-0285-0043.

    We will take final action based on our notice of proposed 
rulemaking that was published in the Federal Register on July 21, 2010 
(75 FR 42346), the comments we received on that proposal, Colorado's 
October 2010 revised modeling, and any comments we receive in response 
to this NODA.

List of Subjects in 40 CFR Part 52

    Environmental protection, Air pollution control, Carbon monoxide, 
Incorporation by Reference, Intergovernmental relations, Lead, Nitrogen 
dioxide, Ozone, Particulate matter, Reporting and recordkeeping 
requirements, Sulfur oxides, Volatile organic compounds.

    Dated: December 10, 2010.
Carol Rushin,
Deputy Regional Administrator, Region 8.
[FR Doc. 2010-31738 Filed 12-16-10; 8:45 am]
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