Skip to Content


Review of the Secondary National Ambient Air Quality Standards for Oxides of Nitrogen and Oxides of Sulfur

Document Details

Information about this document as published in the Federal Register.

Enhanced Content

Relevant information about this document from provides additional context. This information is not part of the official Federal Register document.

Published Document

This document has been published in the Federal Register. Use the PDF linked in the document sidebar for the official electronic format.

Start Preamble Start Printed Page 20595


Environmental Protection Agency (EPA).


Notice of extension of comment period.


The EPA is announcing an extension of the public comment period for a draft assessment document titled, Policy Assessment for the Review of the Secondary National Ambient Air Quality Standards for Oxides of Nitrogen and Oxides of Sulfur: First External Review Draft (75 FR 11877; March 12, 2010). The comment period was originally scheduled to end on April 29, 2010. The extended comment period will close on May 13, 2010. The Agency is extending the comment period by two weeks to provide the public with adequate time to conduct appropriate analysis and prepare meaningful comments.

Although EPA is extending the comment period for the first draft policy assessment by two weeks, EPA is committed to issuing a proposal addressing the nitrogen oxides (NOX) and sulfur oxides (SOX) secondary National Ambient Air Quality Standards (NAAQS) by July 12, 2011. The extension also will not alter EPA's internal schedule for providing a second draft policy assessment for review by the Clean Air Scientific Advisory Committee (CASAC) by the end of July 2010.

The public is encouraged to submit comments by the end of the original comment period to ensure that EPA has adequate time to evaluate and respond to those comments. However, all comments received by May 13, 2010, will be considered in developing the second draft policy assessment.


Comments should be submitted on or before May 13, 2010.


Submit your comments, identified by Docket ID No. EPA-HQ-OAR-2007-1145, by one of the following methods:

  • Follow the on-line instructions for submitting comments.
  • E-mail: Comments may be sent by electronic mail (e-mail) to, Attention Docket ID No. EPA-HQ-OAR-2007-1145.
  • Fax: Fax your comments to 202-566-9744, Attention Docket ID. No. EPA-HQ-OAR-2007-1145.
  • Mail: Send your comments to: Air and Radiation Docket and Information Center, Environmental Protection Agency, Mailcode: 2822T, 1200 Pennsylvania Ave., NW., Washington, DC 20460, Attention Docket ID No. EPA-HQ-OAR-2007-1145.
  • Hand Delivery or Courier: Deliver your comments to: EPA Docket Center, 1301 Constitution Ave., NW., Room 3334, Washington, DC. Such deliveries are only accepted during the Docket's normal hours of operation, and special arrangements should be made for deliveries of boxed information.

Instructions: Direct your comments to Docket ID No. EPA-HQ-OAR-2007-1145. The EPA's policy is that all comments received will be included in the public docket without change and may be made available online at, 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 or e-mail. The 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, 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.

Docket: All documents in the docket are listed in the 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 or in hard copy at the Air Docket in the EPA Docket Center, EPA West, Room 3334, 1301 Constitution Ave., NW., Washington, DC. This Docket Facility is open from 8:30 a.m. to 4:30 p.m., Monday through Friday, excluding legal holidays. The Docket telephone number is 202-566-1742; fax 202-566-9744.

Start Further Info


Dr. Bryan Hubbell, Office of Air Quality Planning and Standards (Mail code C504-02), U.S. Environmental Protection Agency, Research Triangle Park, NC 27711; e-mail:; telephone: 919-541-0621; fax: 919-541-0804.

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 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.Start Printed Page 20596
  • Make sure to submit your comments by the comment period deadline identified.

Under section 108(a) of the Clean Air Act (CAA), the Administrator identifies and lists certain pollutants which “cause or contribute to air pollution which may reasonably be anticipated to endanger public health or welfare.” The EPA then issues air quality criteria for these listed pollutants, which are commonly referred to as “criteria pollutants.” The air quality criteria are to “accurately reflect the latest scientific knowledge useful in indicating the kind and extent of all identifiable effects on public health or welfare which may be expected from the presence of [a] pollutant in the ambient air, in varying quantities.” Under section 109 of the CAA, EPA establishes NAAQS for each listed pollutant, based on the air quality criteria. Section 109(d) of the CAA requires periodic review and, if appropriate, revision of existing air quality criteria. The revised air quality criteria reflect advances in scientific knowledge on the effects of the pollutant on public health or welfare. Section 109 (d) also requires EPA to periodically review and revise the NAAQS, if appropriate, based on the revised criteria.

The EPA is currently conducting a joint review of the existing secondary (welfare-based) NAAQS for NOX and SOX. Because NOX, SOX, and their associated transformation products are linked from an atmospheric chemistry perspective as well as from an environmental effects perspective, and because of the National Research Council's 2004 recommendations to consider multiple pollutants in forming the scientific basis for the NAAQS, EPA has decided to jointly assess the science, risks, and policies relevant to protecting the public welfare associated with NOX and SOX. This is the first time since NAAQS were established in 1971 that a joint review of these two pollutants has been conducted.

As part of this review of the current secondary (welfare-based) NAAQS for NOX and SOX, EPA's Office of Air Quality Planning and Standards staff have prepared a first draft Policy Assessment. The objective of this assessment is to evaluate the policy implications of the key scientific information contained in the document Integrated Science Assessment for Oxides of Nitrogen and Sulfur-Ecological Criteria (​ncea/​cfm/​recordisplay.cfm?​deid=​201485), prepared by EPA's National Center for Environmental Assessment (NCEA) and the results from the analyses contained in the Risk and Exposure Assessment for Review of the Secondary National Ambient Air Quality Standards for Oxides of Nitrogen and Oxides of Sulfur (​ttn/​naaqs/​standards/​no2so2sec/​cr_​rea.html). The first draft Policy Assessment is available online at:​ttn/​naaqs/​standards/​no2so2sec/​index.html. The first draft Policy Assessment was reviewed by the CASAC during a public meeting held on April 1 and 2, 2010. Information about this public meeting is available at​sab/​sabpeople.nsf/​WebCommittees/​CASAC.

At the April 1 and 2, 2010, CASAC meeting, the Committee reviewed the first draft Policy Assessment, heard public comments, and prepared a draft letter to the Agency with their advice regarding the first draft Policy Assessment.

The original comment period for the first draft Policy Assessment was 60 days, from March 1, 2010, through April 29, 2010. In a letter dated April 8, 2010, the Utility Air Regulatory Group requested an extension of the comment period through May 13, 2010. As of April 12, 2010, EPA has received comments from one public commenter presented at the CASAC meeting on April 1, 2010. Based on our consideration of the request from the Utility Air Regulatory Group, EPA is granting the extension of the public comment period through May 13, 2010.

Start Signature

Dated: April 13, 2010.

Jennifer Noonan Edmonds,

Acting Director, Office of Air Quality Planning and Standards.

End Signature End Further Info End Preamble

[FR Doc. 2010-9069 Filed 4-19-10; 8:45 am]