Part 50 - National Primary and Secondary Ambient Air Quality Standards

Part 51 - Requirements for Preparation, Adoption, and Submittal of Implementation Plans

Part 52 - Approval and Promulgation of Implementation Plans

Part 53 - Ambient Air Monitoring Reference and Equivalent Methods

Part 54 - Prior Notice of Citizen Suits

Part 55 - Outer Continental Shelf Air Regulations

Part 56 - Regional Consistency

Part 57 - Primary Nonferrous Smelter Orders

Part 58 - Ambient Air Quality Surveillance

Part 59 - National Volatile Organic Compound Emission Standards for Consumer and Commercial Products

Part 60 - Standards of Performance for New Stationary Sources

Part 61 - National Emission Standards for Hazardous Air Pollutants

Part 62 - Approval and Promulgation of State Plans for Designated Facilities and Pollutants

Part 63 - National Emission Standards for Hazardous Air Pollutants for Source Categories

Part 64 - Compliance Assurance Monitoring

Part 65 - Consolidated Federal Air Rule

Part 66 - Assessment and Collection of Noncompliance Penalties by EPA

Part 67 - EPA Approval of State Noncompliance Penalty Program

Part 68 - Chemical Accident Prevention Provisions

Part 69 - Special Exemptions from Requirements of the Clean Air Act

Part 70 - State Operating Permit Programs

Part 71 - Federal Operating Permit Programs

Part 72 - Permits Regulation

Part 73 - Sulfur Dioxide Allowance System

Part 74 - Sulfur Dioxide Opt-INS

Part 75 - Continuous Emission Monitoring

Part 76 - Acid Rain Nitrogen Oxides Emission Reduction Program

Part 77 - Excess Emissions

Part 78 - Appeal Procedures

Part 79 - Registration of Fuels and Fuel Additives

Part 80 - Regulation of Fuels and Fuel Additives

Part 81 - Designation of Areas for Air Quality Planning Purposes

Part 82 - Protection of Stratospheric Ozone

Parts 83 - [Reserved]

Part 84 - Phasedown of Hydrofluorocarbons

Part 85 - Control of Air Pollution from Mobile Sources

Part 86 - Control of Emissions from New and in-Use Highway Vehicles and Engines

Part 87 - Control of Air Pollution from Aircraft and Aircraft Engines

Part 88 - Clean-Fuel Vehicles

Part 89 - Control of Emissions from New and in-Use Nonroad Compression-Ignition Engines

Part 90 - Control of Emissions from Nonroad Spark-Ignition Engines at or Below 19 Kilowatts

Part 91 - Control of Emissions from Marine Spark-Ignition Engines

Part 92 - Control of Air Pollution from Locomotives and Locomotive Engines

Part 93 - Determining Conformity of Federal Actions to State or Federal Implementation Plans

Part 94 - Control of Emissions from Marine Compression-Ignition Engines

Part 95 - Mandatory Patent Licenses

Part 96 - NOX Budget Trading Program and CAIR NOX and SO2 Trading Programs for State Implementation Plans

Part 97 - Federal NOX Budget Trading Program, CAIR NOX and SO2 Trading Programs, CSAPR NOX and SO2 Trading Programs, and Texas SO2 Trading Program

Part 98 - Mandatory Greenhouse Gas Reporting

Part 99 - [Reserved]

Parts 83--84 - [Reserved]