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Draft Risk and Exposure Assessment Report for Nitrogen Dioxide (NOX

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Information about this document as published in the Federal Register.

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

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Environmental Protection Agency (EPA).


Notice of draft report for public review and comment.


On or about August 12, 2008, the Office of Air Quality Planning and Standards (OAQPS) of EPA is making available for public review and comment a draft document titled, Risk and Exposure Assessment to Support the Review of the NO2Primary National Ambient Air Quality Standard: Second Draft. This draft document has two purposes: To convey the approaches taken to characterize exposures and risks associated with ambient NO2, and to present the results of these analyses.


Comments on the above reports must be received on or before September 26, 2008.


Submit your comments, identified by Docket ID No. EPA-HQ-OAR-2006-0922, 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-2006-0922.
  • Fax: Fax your comments to 202-566-9744, Attention Docket ID No. EPA-HQ-OAR-2006-0922.
  • 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-2006-0922.
  • 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-2006-0922. 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 Start Printed Page 51298comment, EPA recommends that you include your name and other contact information in the body of your comment and with any disk or CD-ROM you submit. If EPA cannot read your comment due to technical difficulties and cannot contact you for clarification, EPA may not be able to consider your comment. Electronic files should avoid the use of special characters, any form of encryption, and be free of any defects or viruses. For additional information about EPA's public docket visit the EPA Docket Center home page at​epahome/​dockets.htm.

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.

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Dr. Scott Jenkins, Office of Air Quality Planning and Standards (Mailcode C504-06), U.S. Environmental Protection Agency, Research Triangle Park, NC 27711; e-mail:; telephone: 919-541-1167; fax: 919-541-0237.

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.
  • 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.
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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 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 national ambient air quality standards (NAAQS) for each listed pollutant, with the NAAQS 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. The EPA is also required to periodically review and revise the NAAQS, if appropriate, based on the revised criteria.

Air quality criteria have been established for the nitrogen oxides (NOX) and NAAQS have been established for nitrogen dioxide (NO2), an indicator for gaseous NOX. Presently, EPA is in the process of reviewing the NAAQS for NO2. As part of its review of the NAAQS, EPA is preparing an assessment of exposures and health risks associated with ambient NO2. A draft plan describing the proposed approaches to assessing exposures and risks is described in the draft document, Nitrogen Dioxide Health Assessment Plan: Scope and Methods for Exposure and Risk Assessment. This document was released for public review and comment in September 2007 and was the subject of a consultation with the Clean Air Scientific Advisory Committee (CASAC) on October 24 and 25, 2007. Comments received from that consultation were considered in developing the document titled, Risk and Exposure Assessment to Support the Review of the NO2Primary National Ambient Air Quality Standard: First Draft, which was released for public review and comment in April 2008. This document was the subject of a CASAC review on May 1 and 2, 2008. Comments received from that review have been considered in developing the document titled, Risk and Exposure Assessment to Support the Review of the NO2Primary National Ambient Air Quality Standard: Second Draft, which is being released at this time.

This draft document is available online at:​ttn/​naaqs/​standards/​nox/​s_​nox_​cr_​rea.html. It has two primary purposes: To convey the approaches taken to characterize exposures and risks associated with ambient NO2, and to present the results of these analyses. The EPA has solicited advice and recommendations from the CASAC by means of a review of the draft document at a public meeting to be held on September 9-10, 2008 in Research Triangle Park, North Carolina. A separate Federal Register notice will provide additional details about this meeting and the process for participation. In preparing a final risk and exposure assessment report, EPA will consider comments received from the CASAC and the public at this upcoming meeting.

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Dated: August 7, 2008.

Jennifer Edmonds,

Acting Director, Office of Air Quality Planning and Standards.

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[FR Doc. E8-20240 Filed 8-29-08; 8:45 am]