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Integrated Science Assessment for Ozone and Related Photochemical Oxidants (External Review Draft)

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Environmental Protection Agency (EPA).


Notice of public comment period.


The Environmental Protection Agency (EPA) is announcing a public comment period for the draft document titled, “Integrated Science Assessment for Ozone and Related Photochemical Oxidants (External Review Draft)” (EPA/600/R-19/093). The draft document was prepared by the National Center for Environmental Assessment (NCEA) within EPA's Office of Research and Development (ORD) as part of the review of the primary (health-based) Start Printed Page 50837and secondary (welfare-based) ozone national ambient air quality standards (NAAQS). The Integrated Science Assessment (ISA), in conjunction with additional technical and policy assessments, provides the scientific basis for EPA's decisions on the adequacy of the current review of the ozone NAAQS and the appropriateness of possible alternative standards.

EPA is releasing this draft document to seek review by the Clean Air Scientific Advisory Committee (CASAC) and the public. In addition, the date and location of a public meeting for CASAC review of this document will be specified in a separate Federal Register document. This draft document is not final, and it does not represent, and should not be construed to represent, any final Agency policy or views. When revising the document, EPA will consider any public comments submitted during the public comment period specified in this document.


The public comment period begins on September 26, 2019 and ends December 2, 2019. Comments must be received on or before December 2, 2019.


The “Integrated Science Assessment for Ozone and Related Photochemical Oxidants (External Review Draft)” will be available primarily via the internet on EPA's Integrated Science Assessment for Ozone page at​isa/​integrated-science-assessment-isa-ozone-and-related-photochemical-oxidants or the public docket at, Docket ID: EPA-HQ-ORD-2018-0274. A limited number of CD-ROM copies will be available. Contact Ms. Marieka Boyd by phone: 919-541-0031; fax: 919-541-5078; or email: to request a CD-ROM, and please provide your name, your mailing address, and the document title, “Integrated Science Assessment for Ozone and Related Photochemical Oxidants (External Review Draft)” to facilitate processing of your request.

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For information on the public comment period, contact the ORD Docket at the EPA Headquarters Docket Center; phone: 202-566-1752; fax: 202-566-9744; or email:

For technical information, contact Dr. Thomas Luben, NCEA; phone: 919-541-5762; fax: 919-541-1818; or email:

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I. Information About the Document

Section 108(a) of the Clean Air Act directs the Administrator to identify and list certain air pollutants and to issue air quality criteria for those pollutants. The Administrator is to list those pollutants “emissions of which, 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 he “plans to issue air quality criteria. . . .” (42 U.S.C. 7408(a)(1)). 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. . . .” (42 U.S.C. 7408(a)(2)). Under section 109 of the Act, EPA is then to establish NAAQS for each pollutant for which EPA has issued criteria. Section 109(d)(1) of the Act subsequently requires periodic review and, if appropriate, revision of existing air quality criteria to reflect advances in scientific knowledge on the effects of the pollutant on public health or welfare. Under the same provision, EPA is also required to periodically review and, if appropriate, revise the NAAQS, based on the revised air quality criteria (for more information on the NAAQS review process, see​criteria-air-pollutants/​process-reviewing-national-ambient-air-quality-standards).

Ozone is one of six criteria pollutants for which EPA has established NAAQS and is the current indicator for related photochemical oxidants. Periodically, EPA reviews the scientific basis for these standards by preparing an ISA (formerly called an Air Quality Criteria Document). The ISA, in conjunction with additional technical and policy assessments, provides the scientific basis for EPA's reviews of these standards NAAQS. Section 109(d)(2) of the Act requires appointment of an independent scientific review committee that is, among other things, to review at five-year intervals the existing air quality criteria and to recommend any revisions of those criteria as may be appropriate. Since the early 1980s, the requirement for an independent scientific review committee has been fulfilled by the Clean Air Scientific Advisory Committee (CASAC).

On June 26, 2018 (83 FR 13716), EPA formally initiated its current review of the air quality criteria for the health and welfare effects of ozone and related photochemical oxidants and the primary (health-based) and secondary (welfare-based) ozone NAAQS, requesting the submission of scientific and policy-relevant information on specified topics. This information was incorporated into EPA's “Integrated Review Plan for the Review of the Ozone National Ambient Air Quality Standards (External Review Draft),” which was available for public comment (83 FR 24037) and discussion by the CASAC via publicly accessible teleconference consultation (83 FR 24269). The final “Integrated Review Plan for the Review of the Ozone National Ambient Air Quality Standards” was posted to the EPA website in August 2019 (​naaqs/​ozone-o3-air-quality-standards).

In the development of the draft ISA, webinar workshops were held on October 29 and 31, 2018, and November 1 and 5, 2018, to discuss initial draft materials with invited EPA and external scientific experts (83 FR 23126). The input received during these webinar workshops aided in the development of the materials presented in the “Integrated Science Assessment for Ozone and Related Photochemical Oxidants (External Review Draft).”

The “Integrated Science Assessment for Ozone and Related Photochemical Oxidants (External Review Draft)” will be discussed at a public meeting for review by CASAC. In addition to the public comment period announced in this notice, the public will have an opportunity to address CASAC at this meeting. A separate Federal Register document will inform the public of the exact date and time of the CASAC meeting and of the procedures for public participation.

II. How To Submit Technical Comments to the Docket at

Submit your comments, identified by Docket ID No. EPA-HQ-ORD-2018-0274, by one of the following methods:

  • Follow the online instructions for submitting comments.
  • Email:
  • Fax: 202-566-9744.
  • Mail: U.S. Environmental Protection Agency, EPA Docket Center (ORD Docket), Mail Code: 28221T, 1200 Pennsylvania Avenue NW, Washington, DC 20460. The phone number is 202-566-1752.
  • Hand Delivery: The ORD Docket is located in the EPA Headquarters Docket Center, EPA West Building, Room 3334, 1301 Constitution Avenue NW, Washington, DC 20004.

The EPA Docket Center Public Reading Room is open from 8:30 a.m. to 4:30 p.m., Monday through Friday, excluding legal holidays. The phone Start Printed Page 50838number for the Public Reading Room is 202-566-1744. Such deliveries are only accepted during the docket's normal hours of operation, and special arrangements should be made for deliveries of boxed information. If you provide comments by mail or hand delivery, please submit three copies of the comments. For attachments, provide an index, number pages consecutively with the comments, and submit an unbound original and three copies.

Instructions: Direct your comments to Docket ID No. EPA-HQ-ORD-2018-0274. Please ensure that your comments are submitted within the specified comment period. Comments received after the closing date will be marked “late.” EPA will attempt to consider late comments to the extent it is practical to do so, but time constraints may not permit consideration of late comments. It is EPA's policy to include all comments it receives in the public docket without change and to make the comments available online at, including any personal information provided, unless a comment includes information claimed to be Confidential Business Information (CBI) or other information whose disclosure is restricted by statute. Do not submit information through or email that you consider to be CBI or otherwise protected. The website 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 email comment directly to EPA without going through, your email 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 information about EPA's public docket visit the EPA Docket Center homepage at​dockets.

Docket: 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 materials, such as copyrighted material, are publicly available only in hard copy. Publicly available docket materials are available either electronically on or in hard copy at the ORD Docket in the EPA Headquarters Docket Center.

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Dated: September 10, 2019.

Tina Bahadori,

Director, National Center for Environmental Assessment.

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[FR Doc. 2019-20925 Filed 9-25-19; 8:45 am]