Review of the Secondary National Ambient Air Quality Standards for Oxides of Nitrogen, Oxides of Sulfur, and Particulate Matter

ENVIRONMENTAL PROTECTION AGENCY <CFR>40 CFR Part 50</CFR> <DEPDOC>[EPA-HQ-OAR-2014-0128; FRL-5788-02-OAR]</DEPDOC> <RIN>RIN 2060-AS35</RIN> <SUBJECT>Review of the Secondary National Ambient Air Quality Standards for Oxides of Nitrogen, Oxides of Sulfur, and Particulate Matter</SUBJECT> <HD SOURCE="HED">AGENCY:</HD> Environmental Protection Agency (EPA). <HD SOURCE="HED">ACTION:</HD> Proposed rule. <SUM> <HD SOURCE="HED">SUMMARY:</HD> Based on the Environmental Protection Agency's (EPA's) review of the air quality criteria and national ambient air quality standards (NAAQS) for oxides of nitrogen (N oxides), oxides of sulfur (SO <E T="52">X</E> ), and particulate matter (PM), the Environmental Protection Agency (EPA) proposes to revise the existing secondary sulfur dioxide (SO <E T="52">2</E> ) standard to an annual average, averaged over three consecutive years, with a level within the range from 10 to 15 parts per billion (ppb). Additionally, the Agency proposes to retain the existing secondary standards for N oxides and PM, without revision. The EPA also proposes revisions to the data handling requirements for the proposed secondary SO <E T="52">2</E> NAAQS. </SUM> <EFFDATE> <HD SOURCE="HED">DATES:</HD> Comments must be received on or before June 14, 2024. <E T="03">Public Hearings:</E> The EPA will hold a virtual public hearing on this proposed rule. This hearing will be announced in a separate <E T="04">Federal Register</E> notice that provides details, including specific dates, times, and contact information for these hearings. </EFFDATE> <HD SOURCE="HED">ADDRESSES:</HD> You may submit comments, identified by Docket ID No. EPA-HQ-OAR-2014-0128, by any of the following means: • <E T="03">Federal eRulemaking Portal: https://www.regulations.gov/</E> (our preferred method). Follow the online instructions for submitting comments. • <E T="03">Email: a-and-r-Docket@epa.gov.</E> Include the Docket ID No. EPA-HQ-OAR-2014-0128 in the subject line of the message. • <E T="03">Mail:</E> U.S. Environmental Protection Agency, EPA Docket Center, Air and Radiation Docket, Mail Code 28221T, 1200 Pennsylvania Avenue NW, Washington, DC 20460. • <E T="03">Hand Delivery or Courier (by scheduled appointment only):</E> EPA Docket Center, WJC West Building, Room 3334, 1301 Constitution Avenue NW, Washington, DC 20004. The Docket Center's hours of operations are 8:30 a.m.-4:30 p.m., Monday-Friday (except Federal Holidays). <E T="03">Instructions:</E> All submissions received must include the Docket ID No. for this document. Comments received may be posted without change to <E T="03">https://www.regulations.gov,</E> including any personal information provided. For detailed instructions on sending comments and additional information on the rulemaking process, see the <E T="02">SUPPLEMENTARY INFORMATION</E> section of this document. <FURINF> <HD SOURCE="HED">FOR FURTHER INFORMATION CONTACT:</HD> Ms. Ginger Tennant, Health and Environmental Impacts Division, Office of Air Quality Planning and Standards, U.S. Environmental Protection Agency, Mail Code C539-04, Research Triangle Park, NC 27711; telephone: (919) 541-4072; email: <E T="03">tennant.ginger@epa.gov.</E> </FURINF> <SUPLINF> <HD SOURCE="HED">SUPPLEMENTARY INFORMATION:</HD> <HD SOURCE="HD1">General Information</HD> <HD SOURCE="HD2">Preparing Comments for the EPA</HD> Follow the online instructions for submitting comments. Once submitted to the Federal eRulemaking Portal, 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 submission. 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 ( <E T="03">i.e.,</E> on the web, the 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 <E T="03">https://www.epa.gov/dockets/commenting-epa-dockets.</E> When submitting comments, remember to: • Identify the action by docket number and other identifying information (subject heading, <E T="04">Federal Register</E> date and page 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. • 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. <HD SOURCE="HD2">Availability of Information Related to This Action</HD> All documents in the dockets pertaining to this action are listed on the <E T="03">www.regulations.gov</E> website. This includes documents in the docket for the proposed decision (Docket ID No. EPA-HQ-OAR-2014-0128) and a separate docket, established for the Integrated Science Assessment (ISA) (Docket ID No. EPA-HQ-ORD-2013-0620) that has been incorporated by reference into the docket for this proposed decision. Although listed in the index, some information is not publicly available, <E T="03">e.g.,</E> CBI or other information whose disclosure is restricted by statute. Certain other material, such as copyrighted material, is not placed on the internet and may be viewed with prior arrangement with the EPA Docket Center. Additionally, a number of the documents that are relevant to this proposed decision are available through the EPA's website at <E T="03">https://www.epa.gov/naaqs/.</E> These documents include the Integrated Science Assessment for Oxides of Nitrogen, Oxides of Sulfur and Particulate Matter Ecological Criteria (U.S. EPA, 2020a), available at <E T="03">https://cfpub.epa.gov/ncea/isa/recordisplay.cfm?deid=349473,</E> and the Policy Assessment for the Review of the Secondary National Ambient Air Quality Standards for Oxides of Nitrogen, Oxides of Sulfur, and Particulate Matter, (U.S. EPA, 2024), available at <E T="03">https://www.epa.gov/naaqs/nitrogen-dioxide-no2-and-sulfur-dioxide-so2-secondary-air-quality-standards.</E> <HD SOURCE="HD1">Table of Contents</HD> The following topics are discussed in this preamble: <EXTRACT> <FP SOURCE="FP-2">Executive Summary</FP> <FP SOURCE="FP-2">I. Background</FP> <FP SOURCE="FP1-2">A. Legislative Requirements</FP> <FP SOURCE="FP1-2">B. Related Control Programs</FP> <FP SOURCE="FP1-2"> C. History of the Secondary Standards for N Oxides, SO <E T="52">X</E> and PM </FP> <FP SOURCE="FP1-2">1. N Oxides</FP> <FP SOURCE="FP1-2"> 2. SO <E T="52">X</E> </FP> <FP SOURCE="FP1-2">3. Related Actions Addressing Acid Deposition</FP> <FP SOURCE="FP1-2"> 4. Most Recent Review of the Secondary Standards for N Oxides and SO <E T="52">X</E> </FP> <FP SOURCE="FP1-2">5. PM</FP> <FP SOURCE="FP1-2">D. Current Review</FP> <FP SOURCE="FP-2">II. Rationale for Proposed Decisions</FP> <FP SOURCE="FP1-2">A. Introduction</FP> <FP SOURCE="FP1-2"> 1. Basis for Existing Secondary Standards </FP> <FP SOURCE="FP1-2">2. Prior Review of Deposition-Related Effects</FP> <FP SOURCE="FP1-2">3. General Approach for This Review</FP> <FP SOURCE="FP1-2">B. Air Quality and Deposition</FP> <FP SOURCE="FP1-2"> 1. Sources, Emissions and Atmospheric Processes Affecting SO <E T="52">X</E> , N Oxides and PM </FP> <FP SOURCE="FP1-2">2. Recent Trends in Emissions, Concentrations and Deposition</FP> <FP SOURCE="FP1-2">3. Relationships Between Concentrations and Deposition</FP> <FP SOURCE="FP1-2">C. Welfare Effects Evidence</FP> <FP SOURCE="FP1-2">1. Nature of Effects</FP> <FP SOURCE="FP1-2"> a. Direct Effects of SO <E T="52">X</E> and N Oxides </FP> <FP SOURCE="FP1-2">b. Acid Deposition-Related Ecological Effects</FP> <FP SOURCE="FP1-2">c. Nitrogen Enrichment and Associated Ecological Effects</FP> <FP SOURCE="FP1-2">d. Other Deposition-Related Effects</FP> <FP SOURCE="FP1-2">2. Public Welfare Implications</FP> <FP SOURCE="FP1-2">3. Exposure Conditions and Deposition-Related Metrics</FP> <FP SOURCE="FP1-2">a. Acidification and Nitrogen Enrichment in Aquatic Ecosystems</FP> <FP SOURCE="FP1-2">b. Deposition-Related Effects in Terrestrial Ecosystems</FP> <FP SOURCE="FP1-2"> c. Direct Effects of N Oxides, SO <E T="52">X</E> and PM in Ambient Air </FP> <FP SOURCE="FP1-2">D. Quantitative Exposure and Risk Assessment for Aquatic Acidification</FP> <FP SOURCE="FP1-2">1. Key Design Aspects</FP> <FP SOURCE="FP1-2">2. Key Limitations and Uncertainties</FP> <FP SOURCE="FP1-2">3. Summary of Results</FP> <FP SOURCE="FP1-2">E. Proposed Conclusions</FP> <FP SOURCE="FP1-2">1. Evidence and Exposure/Risk-Based Considerations in the Policy Assessment</FP> <FP SOURCE="FP1-2">a. Direct Effects on Biota</FP> <FP SOURCE="FP1-2">b. Evidence of Ecosystem Effects of S and N Deposition</FP> <FP SOURCE="FP1-2"> c. Sulfur Deposition and SO <E T="52">X</E> </FP> <FP SOURCE="FP1-2">d. Nitrogen Deposition and N Oxides and PM</FP> <FP SOURCE="FP1-2">2. CASAC Advice and Public Comments</FP> <FP SOURCE="FP1-2">3. Administrator's Proposed Conclusions</FP> <FP SOURCE="FP1-2">F. Proposed Decision on the Secondary Standards</FP> <FP SOURCE="FP-2"> III. Interpretation of the Secondary SO <E T="52">2</E> Standard </FP> <FP SOURCE="FP1-2">A. Background</FP> <FP SOURCE="FP1-2"> B. Interpretation of the Secondary SO <E T ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ Preview showing 10k of 646k characters. Full document text is stored and available for version comparison. ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━