Regulations Explorer
Search and browse federal and state air regulations, guidance and requirements. Every entry links to the official text and shows how far it has been reviewed.
- NSPS40 CFR Part 60New Source Performance Standards. Performance standards for new, modified, and reconstructed sources.
- NESHAP40 CFR Parts 61 and 63National Emission Standards for Hazardous Air Pollutants. Hazardous air pollutant standards, including MACT and GACT source categories.
- Title V40 CFR Parts 70 and 71Title V Operating Permits. Operating permits that consolidate a source's applicable requirements.
- NSR40 CFR 51.160–51.166; 40 CFR 52.21New Source Review. Preconstruction permitting for new and modified sources.
- PSD40 CFR 52.21; 40 CFR 51.166Prevention of Significant Deterioration. Major NSR for attainment and unclassifiable areas.
- NNSR40 CFR 51.165Nonattainment New Source Review. Major NSR for areas that do not meet air quality standards.
- AP-42EPA AP-42Compilation of Air Pollutant Emission Factors. EPA's primary compilation of emission factors for stationary sources.
- GHG Reporting40 CFR Part 98Greenhouse Gas Reporting Program. Mandatory annual reporting of greenhouse gas data from covered source categories.
- MACT standards40 CFR Part 63Maximum Achievable Control Technology standards for major sources of hazardous air pollutants, organized by source category in Part 63.
- State regulationsAir agency rules, permit programs, forms, and guidance for all 50 states and DC.
- EPA guidance documentsProgram pages, emission factor references, and nonattainment designations from EPA.
Federal summaries describe program structure only and are marked “not yet reviewed” until an editor checks them against the eCFR. Thresholds, limits, and deadlines always come from the official text.
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