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Emission Standards Reference Guide

All EPA Emission Standards

Light-Duty Vehicles and Trucks and Motorcycles

View the light-duty vehicles and trucks standards:

  • Clean Fuel Fleet -- exhaust emission standards
  • Clean Fuel Fleet flexible fuel and dual fuel vehicles -- non-methane organic gas standards
  • Tier 0, Tier 1, and Clean Fuel Vehicle (CFV) exhaust emission standards (light-duty trucks only)
  • Tier 0, Tier 1, and National Low Emission Vehicle (NLEV) implementation schedule
  • Tier 0, Tier 1, NLEV, and CFV exhaust emission standards
  • Tier 1 and NLEV Supplemental Federal Test Procedure (SFTP) exhaust emission standards
  • Tier 1 and NLEV evaporative emission standards and implementation schedule
  • Tier 2 and interim non-Tier 2 SFTP exhaust emission standards
  • Tier 2 evaporative emission standards
  • Tier 2 exhaust emission standards and implementation schedule

Driving Cycles

Heavy-Duty Highway Engines and Vehicles

View the heavy-duty vehicles and trucks standards:

  • Clean Fuel Fleet program -- exhaust emission standards
  • Compression-ignition (CI) engines and urban buses -- exhaust emission standards
  • Spark-ignition (SI) engines -- exhaust emission standards
  • SI and CI engines -- evaporative emission standards

Nonroad Engines and Vehicles

View the nonroad engines and vehicles standards:

  • Aircraft -- exhaust emission standards
  • CI engines -- exhaust emission standards
  • Large SI engines -- exhaust and evaporative emission standards
  • Locomotives -- exhaust emission standards
  • Marine CI engines -- exhaust emission standards
  • Marine SI engines and vessels -- exhaust emission standards
  • Recreational engines and vehicles -- exhaust emission standards
  • SI engines 19 kilowatts (kW) and below -- exhaust emission standards
  • SI engines 19kW and below, recreational engines and vehicles, and marine SI engines -- evaporative emission standards

Fuel Sulfur Standards

View the fuel sulfur standards:

  • Gasoline sulfur standards
  • Highway, nonroad, locomotive, and marine (NRLM) diesel fuel sulfur standards