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Release of Risk and Exposure Assessment Planning Document for the Review of the Primary National Ambient Air Quality Standards for Sulfur Oxides

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Information about this document as published in the Federal Register.

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Environmental Protection Agency (EPA).


Notice of availability.


The Environmental Protection Agency (EPA) is conducting a periodic review of the air quality criteria and the primary National Ambient Air Quality Standards (NAAQS) for Sulfur Oxides (SOX). On or about February 16, 2017, the EPA will make available for public review the document titled Review of the Primary National Ambient Air Quality Standards for Sulfur Oxides: Risk and Exposure Assessment Planning Document (REA Planning Document). This plan presents considerations and the proposed approach for conducting quantitative analyses of sulfur dioxide (SO2) exposures and health risks in this NAAQS review. This planning document is intended to facilitate consultation with the Clean Air Scientific Advisory Committee (CASAC) and public comment on plans for such quantitative analyses.


Comments should be received on or before April 13, 2017.


Submit your comments, identified by Docket ID No. EPA-HQ-OAR-2013-0566, to the Federal eRulemaking Portal: Follow the online instructions for submitting comments. Once submitted, comments cannot be edited or withdrawn. The 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. The 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 methods, the full EPA public comment policy, information about CBI or multimedia submissions, and general guidance on making effective comments, please visit Start Printed Page 11357​dockets/​commenting-epa-dockets. The REA Planning Document will be available primarily via the Internet at​naaqs/​sulfur-dioxide-so2-primary-standards-planning-documents-current-review.

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Dr. Nicole Hagan, Office of Air Quality Planning and Standards (Mail Code C504-06), U.S. Environmental Protection Agency, Research Triangle Park, NC 27711; telephone number: 919-541-3153; fax number: 919-541-5315; email:

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I. General Information

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

1. Submitting CBI. Do not submit this information to EPA through or email. 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 Code of Federal Regulations (CFR) part 2.

2. Tips for Preparing your Comments. When submitting comments, remember to:

  • Identify the notice 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 CFR part or section number.
  • Explain why you agree or disagree; suggest alternative and substitute language for your requested changes.
  • Describe any assumption 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. Information About the Document

Two sections of the Clean Air Act (CAA) govern the establishment and revision of the NAAQS. Section 108 (42 U.S.C. 7408) directs the Administrator to identify and list certain air pollutants and then to issue air quality criteria for those pollutants. The Administrator is to list those air pollutants that in his “judgment, cause or contribute to air pollution which may reasonably be anticipated to endanger public health or welfare”; “the presence of which in the ambient air results from numerous or diverse mobile or stationary sources”; and “for which . . . [the Administrator] plans to issue air quality criteria . . .” (42 U.S.C. 7408(a)(1)(A)-(C)). Air quality criteria are intended 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 . . .” (42 U.S.C. 7408(a)(2)). Under section 109 (42 U.S.C. 7409), the EPA establishes primary (health-based) and secondary (welfare-based) NAAQS for pollutants for which air quality criteria are issued. Section 109(d) 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. Section 109(d)(2) requires that an independent scientific review committee “shall complete a review of the criteria . . . and the national primary and secondary ambient air quality standards . . . and shall recommend to the Administrator any new . . . standards and revisions of the existing criteria and standards as may be appropriate . . . .” Since the early 1980s, this independent review function has been performed by the CASAC.

Presently, the EPA is reviewing the air quality criteria and primary NAAQS for SOx.[1] The EPA's overall plan for this review is presented in the Integrated Review Plan for the Primary NAAQS for Sulfur Dioxide (IRP).[2] The REA Planning Document considers the degree to which important uncertainties identified in quantitative analyses from previous reviews have been addressed by newly available scientific evidence, tools, or information, including those in the second draft Integrated Science Assessment for Sulfur Oxides—Health Criteria (ISA).[3] Based on these considerations, the document reaches preliminary conclusions on the extent to which updated quantitative analyses of exposures or health risks are warranted in the current review. For updated analyses that are supported, this planning document presents anticipated approaches to conducting such analyses. This document will be available on or about February 16, 2017, on the EPA's Technology Transfer Network Web site at​naaqs/​sulfur-dioxide-so2-primary-standards-planning-documents-current-review.

The REA Planning Document has been made available for consultation with the CASAC at an upcoming public meeting of the CASAC. A separate Federal Register notice will provide details about this meeting and the process for participation. The EPA will also consider public comments on the REA Planning Document that are submitted to the docket, as described above.

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Dated: February 13, 2017.

Stephen Page,

Director, Office of Air Quality Planning and Standards.

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1.  The indicator for the current standard is SO2.

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3.  The second draft ISA was made available to both CASAC and the public in December 2016 (81 FR 89097) and is available at:​naaqs/​sulfur-dioxide-so2-primary-standards-integrated-science-assessments-current-review.

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[FR Doc. 2017-03432 Filed 2-21-17; 8:45 am]