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Release of Draft Documents Related to the Review of the Primary National Ambient Air Quality Standard for Sulfur Oxides

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Environmental Protection Agency (EPA).


Notice of availability.


On or about August 25, 2017, the Environmental Protection Agency (EPA) will make available for public comment two draft documents titled, Risk and Exposure Assessment for the Review of the Primary National Ambient Air Quality Standard for Sulfur Oxides, External Review Draft (Draft REA) and Policy Assessment for the Review of the Primary National Ambient Air Quality Standard for Sulfur Oxides, External Review Draft (Draft PA). These draft documents were prepared as part of the current review of the primary National Ambient Air Quality Standard (NAAQS) for Sulfur Oxides (SOX). The Draft REA describes draft quantitative exposure and risk analyses for this NAAQS review. The PA, when final, serves to “bridge the gap” between the currently available scientific information and the judgments required of the Administrator in determining whether to retain or revise the existing primary NAAQS for SOX.


Comments should be received on or before October 18, 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 Once submitted, comments cannot be edited or withdrawn.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​dockets/​commenting-epa-dockets. The draft REA and draft PA will be available primarily via the Internet at​naaqs/​sulfur-dioxide-so2-primary-air-quality-standards.

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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 Clean Air Start Printed Page 43757Scientific Advisory Committee (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] As described in the IRP, the EPA is preparing an Integrated Science Assessment for Sulfur Oxides—Health Criteria (ISA), the second draft [3] of which was reviewed by the CASAC, along with the Risk and Exposure Assessment Planning Document for the Review of the Primary National Ambient Air Quality Standards for Sulfur Oxides (REA Planning Document),[4] at a public meeting in March 2017 (82 FR 11449). The draft REA announced today describes the approaches taken to assess SO2 exposures and associated health risks, as well as presents the initial key results, observations, and related uncertainties associated with the quantitative analyses performed. The PA, when final, serves to “bridge the gap” between the scientific and technical information in the final ISA and REA, and the judgments required of the Administrator in determining whether to retain or revise the existing primary NAAQS for SOX. The draft PA builds upon information presented in the second draft ISA and the draft REA. The draft REA and PA documents will be available on or about August 25, 2017, on the EPA's Technology Transfer Network Web site at​naaqs/​sulfur-dioxide-so2-primary-air-quality-standards.

The EPA is soliciting advice and recommendations from the CASAC by means of a review of these draft documents at an upcoming public meeting of the CASAC. Information about this public meeting, including the dates and location, will be published as a separate notice in the Federal Register. Following the CASAC meeting, the EPA will consider comments received from the CASAC and the public in preparing revisions to these documents.

The draft documents briefly described above do not represent and should not be construed to represent any final EPA policy, viewpoint, or determination. The EPA will consider any public comments submitted in response to this notice when revising the documents.

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Dated: August 14, 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 the 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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4.  The REA Planning Document was made available to both the CASAC and the public in February 2017 (82 FR 11356) and is available at:​naaqs/​sulfur-dioxide-so2-primary-standards-planning-documents-current-review.

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[FR Doc. 2017-19823 Filed 9-18-17; 8:45 am]