SUPPLEMENTARY INFORMATION:

I. General Information

Written Comments

Submit your comments, identified by Docket ID No. EPA-HQ-OAR-2023-0317, at https://www.regulations.gov (our preferred method), or the other methods identified in the ADDRESSES section. Once submitted, comments cannot be edited or removed from the docket. The EPA may publish any comment received to its public docket. Do not submit to EPA's docket at https://www.regulations.gov any information you consider Confidential Business Information (CBI), Proprietary Business Information (PBI), 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 a 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). Please visit https://www.epa.gov/​dockets/​commenting-epa-dockets for additional submission methods; the full EPA public comment policy; information about CBI, PBI, or multimedia submissions; and general guidance on making effective comments.

II. Information About the Documents

Two sections of the Clean Air Act (CAA or the Act) govern the establishment and revision of the NAAQS. Section 108 directs the Administrator to identify and list certain air pollutants and then issue “air quality criteria” for those 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 such pollutant in the ambient air . . .” (CAA section 108(a)(2)). Under section 109 of the Act, the EPA is then to establish primary (health-based) and secondary (welfare-based) NAAQS for each pollutant for which the EPA has issued air quality criteria. Section 109(d)(1) of the Act requires periodic review and, if appropriate, revision of existing air quality criteria. Revised air quality criteria are to reflect advances in scientific knowledge on the effects of the pollutant on public health and welfare. Under the same provision, the EPA is also to periodically review and, if appropriate, revise the NAAQS based on the revised air quality criteria.

The Act additionally requires the appointment of an independent scientific review committee that is to periodically review the existing air quality criteria and NAAQS and to recommend any new standards and revisions of existing criteria and standards as may be appropriate (CAA section 109(d)(2)(A)-(B)). Since the early 1980s, the Clean Air Scientific Advisory Committee (CASAC) has fulfilled the requirement for an independent scientific review committee.

Presently, the EPA is reviewing the health-based air quality criteria and primary NAAQS for oxides of nitrogen. The EPA's call for information for this review was issued on December 9, 2022 (87 FR 75625), and requested the public's assistance in identifying relevant scientific information for the review that has become available since the cutoff date for the 2016 ISA ( i.e., March 2014).^[1] The documents announced in this notice have been developed as part of the integrated review plan (IRP) which is developed in the planning phase for the review. The documents have been prepared jointly by the EPA's Center for Public Health and Environmental Assessment within the Office of Research and Development and the Office of Air Quality Planning and Standards within the Office of Air and Radiation. These documents will be available on the EPA's website: https://www.epa.gov/​naaqs/​nitrogen-dioxide-no2-primary-air-quality-standards, accessible under “Planning Documents” from the current review.

The IRP for the current review of the primary NAAQS for oxides of nitrogen will be comprised of three volumes. Volumes 1 and 2 are the subject of this notice. Volume 1 provides background information on the air quality criteria and standards for oxides of nitrogen and may serve as a reference by the public and the CASAC in their consideration of the subsequent two volumes. Volume 2 addresses the general approach for the review and planning for the integrated science assessment (ISA). Comments are solicited from the public on Volume 2, which will also be the subject of a consultation with the CASAC, to be announced in a separate Federal Register notice. This volume identifies policy-relevant issues in the review and describes key considerations in the EPA's development of the ISA. Volume 3, which is not yet completed, is the planning document for quantitative analyses to be considered in the policy assessment (PA), including exposure and risk analyses, as warranted. In order that consideration of the availability of new evidence in the review can inform these plans, the development and public availability of Volume 3 will generally coincide with that of the draft ISA, and it will be the subject of a consultation with the CASAC at that time. ( printed page 19310)

As described above, comments on Volume 2 of the IRP should be submitted to the docket by April 17, 2024. A separate Federal Register notice will provide details about the CASAC consultation meeting and the process for participation in the CASAC consultation on Volume 2. The EPA will consider the consultation comments from the CASAC and public comments on the IRP, Volume 2, in preparation of the ISA for Oxides of Nitrogen—Health Criteria. Volume 1 of the IRP, also being made available, provides background or contextual and historical material for this NAAQS review. These documents do not represent and should not be construed to represent any final EPA policy, viewpoint, or determination.