Guideline on Air Quality Models; Enhancements to the AERMOD Dispersion Modeling System

<RULE> ENVIRONMENTAL PROTECTION AGENCY <CFR>40 CFR Part 51</CFR> <DEPDOC>[EPA-HQ-OAR-2022-0872; FRL-10391-02-OAR]</DEPDOC> <RIN>RIN 2060-AV92</RIN> <SUBJECT>Guideline on Air Quality Models; Enhancements to the AERMOD Dispersion Modeling System</SUBJECT> <HD SOURCE="HED">AGENCY:</HD> Environmental Protection Agency (EPA). <HD SOURCE="HED">ACTION:</HD> Final rule. <SUM> <HD SOURCE="HED">SUMMARY:</HD> In this action, the Environmental Protection Agency (EPA) promulgates revisions to the <E T="03">Guideline on Air Quality Models</E> (“ <E T="03">Guideline</E> ”). The <E T="03">Guideline</E> has been incorporated into the EPA's regulations, satisfying a requirement under the Clean Air Act (CAA), for the EPA to specify, with reasonable particularity, models to be used in the Prevention of Significant Deterioration (PSD) program. The <E T="03">Guideline</E> provides EPA-preferred models and other recommended techniques, as well as guidance for their use in predicting ambient concentrations of air pollutants. The EPA is revising the <E T="03">Guideline,</E> including enhancements to the formulation and application of the EPA's near-field dispersion modeling system, AERMOD, and updates to the recommendations for the development of appropriate background concentration for cumulative impact analyses. </SUM> <EFFDATE> <HD SOURCE="HED">DATES:</HD> This rule is effective January 28, 2025. </EFFDATE> <HD SOURCE="HED">ADDRESSES:</HD> The EPA has established a docket for this action under Docket ID No. EPA-HQ-OAR-2022-0872. All documents in the docket are listed on the <E T="03">https://www.regulations.gov</E> website. Although listed in the index, some information is not publicly available, <E T="03">e.g.,</E> Confidential Business Information (CBI) or other information whose disclosure is restricted by statute. Certain other material, such as copyrighted material, is not placed on the internet and will be publicly available only in hard copy form. Publicly available docket materials are available electronically through <E T="03">https://www.regulations.gov.</E> <FURINF> <HD SOURCE="HED">FOR FURTHER INFORMATION CONTACT:</HD> Mr. George M. Bridgers, Office of Air Quality Planning and Standards, Air Quality Assessment Division, Air Quality Modeling Group, U.S. Environmental Protection Agency, Mail code C439-01, Research Triangle Park, NC 27711; telephone: (919) 541-5563; email: <E T="03">Bridgers.George@epa.gov</E> (and include “2024 Revisions to the Guideline on Air Quality Models” in the subject line of the message). </FURINF> <SUPLINF> <HD SOURCE="HED">SUPPLEMENTARY INFORMATION:</HD> The information in this preamble is organized as follows: <HD SOURCE="HD1">Table of Contents</HD> <EXTRACT> <FP SOURCE="FP-2">I. General Information</FP> <FP SOURCE="FP1-2">A. Does this action apply to me?</FP> <FP SOURCE="FP1-2">B. Where can I get a copy of this document?</FP> <FP SOURCE="FP1-2">C. Judicial Review</FP> <FP SOURCE="FP1-2">D. List of Acronyms</FP> <FP SOURCE="FP-2">II. Background</FP> <FP SOURCE="FP1-2"> A. The <E T="03">Guideline on Air Quality Models</E> and EPA Modeling Conferences </FP> <FP SOURCE="FP1-2">B. The Twelfth and Thirteenth Conferences on Air Quality Modeling</FP> <FP SOURCE="FP1-2">C. Alpha and Beta Categorization of Non-Regulatory Options</FP> <FP SOURCE="FP-2"> III. Discussion of Final Action on the Revisions to the <E T="03">Guideline</E> </FP> <FP SOURCE="FP1-2">A. Final Action</FP> <FP SOURCE="FP-2">IV. Ongoing Model Development</FP> <FP SOURCE="FP-2">V. Statutory and Executive Order Reviews</FP> <FP SOURCE="FP1-2">A. Executive Order 12866: Regulatory Planning and Review and Executive Order 14094: Modernizing Regulatory Review</FP> <FP SOURCE="FP1-2">B. Paperwork Reduction Act (PRA)</FP> <FP SOURCE="FP1-2">C. Regulatory Flexibility Act (RFA)</FP> <FP SOURCE="FP1-2">D. Unfunded Mandates Reform Act (UMRA)</FP> <FP SOURCE="FP1-2">E. Executive Order 13132: Federalism</FP> <FP SOURCE="FP1-2">F. Executive Order 13175: Consultation and Coordination With Indian Tribal Governments</FP> <FP SOURCE="FP1-2">G. Executive Order 13045: Protection of Children From Environmental Health Risks and Safety Risks</FP> <FP SOURCE="FP1-2">H. Executive Order 13211: Actions Concerning Regulations That Significantly Affect Energy Supply, Distribution, or Use</FP> <FP SOURCE="FP1-2">I. National Technology Transfer and Advancement Act</FP> <FP SOURCE="FP1-2">J. Executive Order 12898: Federal Actions To Address Environmental Justice in Minority Populations and Low-Income Populations and Executive Order 14096: Revitalizing Our Nation's Commitment to Environmental Justice for All</FP> <FP SOURCE="FP1-2">K. Congressional Review Act (CRA)</FP> </EXTRACT> <HD SOURCE="HD1">I. General Information</HD> <HD SOURCE="HD2">A. Does this action apply to me?</HD> This action applies to Federal, State, territorial, and local air quality management programs that conduct or review air quality modeling as part of State Implementation Plan (SIP) submittals and revisions, New Source Review (NSR), including new or modifying industrial sources under Prevention of Significant Deterioration (PSD), Conformity, and other programs in which air quality assessments are required under EPA regulation. Categories and entities potentially regulated by this action include: <GPOTABLE COLS="2" OPTS="L2,tp0,i1" CDEF="s50,15"> <TTITLE> </TTITLE> <CHED H="1">Category</CHED> <ENT I="01">Federal/State/territorial/local/Tribal government</ENT> <ENT>924110</ENT> </ROW> <TNOTE> <SU>a</SU>  North American Industry Classification System. </TNOTE> </GPOTABLE> <HD SOURCE="HD2">B. Where can I get a copy of this document?</HD> In addition to being available in the docket, an electronic copy of this final rule and relative supporting documentation will also be available on the EPA's Support Center for Regulatory Atmospheric Modeling (SCRAM) website. Following signature, these materials will be posted on SCRAM at the following address: <E T="03">https://www.epa.gov/scram/2024-appendix-w-final-rule.</E> <HD SOURCE="HD2">C. Judicial Review</HD> Under section 307(b)(1) of the Clean Air Act (CAA), this final rule is “nationally applicable” because it revises the <E T="03">Guideline on Air Quality Models,</E> 40 CFR part 51, Appendix W. Therefore, petitions for judicial review of this final action must be filed in the U.S. Court of Appeals for the District of Columbia Circuit by January 28, 2025. Filing a petition for reconsideration by the Administrator of this final action does not affect the finality of the action for the purposes of judicial review, nor does it extend the time within which a petition for judicial review must be filed, and shall not postpone the effectiveness of such action. 42 U.S.C. 7607(b)(1). This rule is also subject to section 307(d) of the CAA because it revises a regulation addressing a requirement under section 165(e)(3)(D) of the CAA, which is included in part C of title I of the CAA (relating to prevention of significant deterioration of air quality and protection of visibility). 42 U.S.C. 7607(d)(1)(J). <HD SOURCE="HD2">D. List of Acronyms</HD> <EXTRACT> <FP SOURCE="FP-1">AEDT Aviation Environmental Design Tool</FP> <FP SOURCE="FP-1">AERMET Meteorological data preprocessor for AERMOD</FP> <FP SOURCE="FP-1">AERMINUTE Pre-processor to AERMET to read 1-minute ASOS data to calculate hourly average winds for input into AERMET</FP> <FP SOURCE="FP-1">AERMOD American Meteorological Society (AMS)/EPA Regulatory Model</FP> <FP SOURCE="FP-1">AERSCREEN Program to run AERMOD in screening mode</FP> <FP SOURCE="FP-1">AERSURFACE Land cover data tool in AERMET</FP> <FP SOURCE="FP-1">AQRV Air Quality Related Value</FP> <FP SOURCE="FP-1">AQS Air Quality System</FP> <FP SOURCE="FP-1">ARM2 Ambient Ratio Method 2</FP> <FP SOURCE="FP-1">ASOS Automated Surface Observing Stations</FP> <FP SOURCE="FP-1">ASTM American Society for Testing and Materials</FP> <FP SOURCE="FP-1"> B <E T="52">o</E>  Bowen ratio </FP> <FP SOURCE="FP-1">BID Buoyancy-induced dispersion</FP> <FP SOURCE="FP-1">BLP Buoyant Line and Point Source model</FP> <FP SOURCE="FP-1">BOEM Bureau of Ocean Energy Management</FP> <FP SOURCE="FP-1">BPIPPRM Building Profile Input Program for PRIME</FP> <FP SOURCE="FP-1">CAA Clean Air Act</FP> <FP SOURCE="FP-1">CAL3QHC Screening version of the CALINE3 model</FP> <FP SOURCE="FP-1">CAL3QHCR Refined version of the CALINE3 model</FP> <FP SOURCE="FP-1">CALINE3 CAlifornia LINE Source Dispersion Model</FP> <FP SOURCE="FP-1">CALMPRO Calms Processor</FP> <FP SOURCE="FP-1">CALPUFF California Puff model</FP> <FP SOURCE="FP-1">CAMx Comprehensive Air Quality Model with Extensions</FP> <FP SOURCE="FP-1">COARE Coupled Ocean-Atmosphere Response Experiment</FP> <FP SOURCE="FP-1">CFR Code of Federal Regulations</FP> <FP SOURCE="FP-1">CMAQ Community Multiscale Air Quality</FP> <FP SOURCE="FP-1">CO Carbon monoxide</FP> <FP SOURCE="FP-1">CTDMPLUS Complex Terrain Dispersion Model Plus Algorithms for Unstable Situations</FP> <FP SOURCE="FP-1">CTSCREEN Screening version of CTDMPLUS</FP> <FP SOURCE="FP-1">CTM Chemical transport model</FP> <FP SOURCE="FP-1">dθ/dz Vertical potential temperature gradient</FP> <FP SOURCE="FP-1">DT Temperature difference</FP> <FP SOURCE="FP-1">EPA Environmental Protection Agency</FP> <FP SOURCE="FP-1">FAA Federal Aviation Administration</FP> <FP SOURCE="FP-1">FHWA Federal Highway Administration</FP> <FP SOURCE="FP-1">FLAG Federal Land Managers' Air Quality Related Values Work Group Phase I Report</FP> <FP SOURCE="FP-1">FLM Federal Land Manager</FP> <FP SOURCE="FP-1">GEP Good engineering practice</FP> <FP SOURCE="FP-1">GRSM Generic Reaction Set Method</FP> <FP SOURCE="FP-1">GUI Graphical user interface</FP> <FP SOURCE="FP-1">IBL Inhomogeneous boundary layer</FP> <FP SOURCE="FP- ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ Preview showing 10k of 364k characters. 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