---
kind: "unit"
title: "40"
title_heading: "Protection of Environment"
key: "chI/subchC"
level: "subchap"
label: "Subchapter C"
heading: "Air Programs"
release: "ecfr-current"
date: "2026-08-27"
url: "https://uscodex.org/cfr/40/chI-subchC"
sections_count: 9694
---

# Subchapter C — Air Programs

Title 40 C.F.R. — Protection of Environment › Chapter I — Environmental Protection Agency

## Contents

- [Part 50 — National Primary and Secondary Ambient Air Quality Standards](/cfr/40/chI-subchC-part50.md)
- [Part 51 — Requirements for Preparation, Adoption, and Submittal of Implementation Plans](/cfr/40/chI-subchC-part51.md)
- [Part 52 — Approval and Promulgation of Implementation Plans](/cfr/40/chI-subchC-part52.md)
- [Part 53 — Ambient Air Monitoring Reference and Equivalent Methods](/cfr/40/chI-subchC-part53.md)
- [Part 54 — Prior Notice of Citizen Suits](/cfr/40/chI-subchC-part54.md)
- [Part 55 — Outer Continental Shelf Air Regulations](/cfr/40/chI-subchC-part55.md)
- [Part 56 — Regional Consistency](/cfr/40/chI-subchC-part56.md)
- [Part 57 — Primary Nonferrous Smelter Orders](/cfr/40/chI-subchC-part57.md)
- [Part 58 — Ambient Air Quality Surveillance](/cfr/40/chI-subchC-part58.md)
- [Part 59 — National Volatile Organic Compound Emission Standards for Consumer and Commercial Products](/cfr/40/chI-subchC-part59.md)
- [Part 60 — Standards of Performance for New Stationary Sources](/cfr/40/chI-subchC-part60.md)
- [Part 61 — National Emission Standards for Hazardous Air Pollutants](/cfr/40/chI-subchC-part61.md)
- [Part 62 — Approval and Promulgation of State Plans for Designated Facilities and Pollutants](/cfr/40/chI-subchC-part62.md)
- [Part 63 — National Emission Standards for Hazardous Air Pollutants for Source Categories](/cfr/40/chI-subchC-part63.md)
- [Part 64 — Compliance Assurance Monitoring](/cfr/40/chI-subchC-part64.md)
- [Part 65 — Consolidated Federal Air Rule](/cfr/40/chI-subchC-part65.md)
- [Part 66 — Assessment and Collection of Noncompliance Penalties by Epa](/cfr/40/chI-subchC-part66.md)
- [Part 67 — Epa Approval of State Noncompliance Penalty Program](/cfr/40/chI-subchC-part67.md)
- [Part 68 — Chemical Accident Prevention Provisions](/cfr/40/chI-subchC-part68.md)
- [Part 69 — Special Exemptions from Requirements of the Clean Air Act](/cfr/40/chI-subchC-part69.md)
- [Part 70 — State Operating Permit Programs](/cfr/40/chI-subchC-part70.md)
- [Part 71 — Federal Operating Permit Programs](/cfr/40/chI-subchC-part71.md)
- [Part 72 — Permits Regulation](/cfr/40/chI-subchC-part72.md)
- [Part 73 — Sulfur Dioxide Allowance System](/cfr/40/chI-subchC-part73.md)
- [Part 74 — Sulfur Dioxide Opt-Ins](/cfr/40/chI-subchC-part74.md)
- [Part 75 — Continuous Emission Monitoring](/cfr/40/chI-subchC-part75.md)
- [Part 76 — Acid Rain Nitrogen Oxides Emission Reduction Program](/cfr/40/chI-subchC-part76.md)
- [Part 77 — Excess Emissions](/cfr/40/chI-subchC-part77.md)
- [Part 78 — Appeal Procedures](/cfr/40/chI-subchC-part78.md)
- [Part 79 — Registration of Fuels and Fuel Additives](/cfr/40/chI-subchC-part79.md)
- [Part 80 — Regulation of Fuels and Fuel Additives](/cfr/40/chI-subchC-part80.md)
- [Part 81 — Designation of Areas for Air Quality Planning Purposes](/cfr/40/chI-subchC-part81.md)
- [Part 82 — Protection of Stratospheric Ozone](/cfr/40/chI-subchC-part82.md)
- [Part 83 — Part 83 [reserved]](/cfr/40/chI-subchC-part83.md)
- [Part 84 — Phasedown of Hydrofluorocarbons](/cfr/40/chI-subchC-part84.md)
- [Part 85 — Control of Air Pollution from Mobile Sources](/cfr/40/chI-subchC-part85.md)
- [Part 86 — Control of Emissions from New and In-Use Highway Vehicles and Engines](/cfr/40/chI-subchC-part86.md)
- [Part 87 — Control of Air Pollution from Aircraft and Aircraft Engines](/cfr/40/chI-subchC-part87.md)
- [Part 88 — Clean-Fuel Vehicles](/cfr/40/chI-subchC-part88.md)
- [Part 89 — Control of Emissions from New and In-Use Nonroad Compression-Ignition Engines](/cfr/40/chI-subchC-part89.md)
- [Part 90 — Control of Emissions from Nonroad Spark-Ignition Engines at or Below 19 Kilowatts](/cfr/40/chI-subchC-part90.md)
- [Part 91 — Control of Emissions from Marine Spark-Ignition Engines](/cfr/40/chI-subchC-part91.md)
- [Part 92 — Control of Air Pollution from Locomotives and Locomotive Engines](/cfr/40/chI-subchC-part92.md)
- [Part 93 — Determining Conformity of Federal Actions to State or Federal Implementation Plans](/cfr/40/chI-subchC-part93.md)
- [Part 94 — Control of Emissions from Marine Compression-Ignition Engines](/cfr/40/chI-subchC-part94.md)
- [Part 95 — Mandatory Patent Licenses](/cfr/40/chI-subchC-part95.md)
- [Part 96 — Nox Budget Trading Program and Cair Nox and So2 Trading Programs for State Implementation Plans](/cfr/40/chI-subchC-part96.md)
- [Part 97 — Federal Nox Budget Trading Program, Cair Nox and So2 Trading Programs, Csapr Nox and So2 Trading Programs, and Texas So2 Trading Program](/cfr/40/chI-subchC-part97.md)
- [Part 98 — Mandatory Greenhouse Gas Reporting](/cfr/40/chI-subchC-part98.md)
- [Part 99 — Part 99 [reserved]](/cfr/40/chI-subchC-part99.md)