Vehicle emissions

We work to protect the air by reducing diesel exhaust, providing information about the emissions testing program, implementing the Clean Car Law, and managing the Volkswagen enforcement actions that resulted from federal and state Clean Air Act violations.

Transportation is Washington's largest source of air pollution and greenhouse gases.

Emission check program

Most of Clark, King, Pierce, Snohomish, and Spokane counties require vehicle emission tests for personal and fleet vehicles. If your vehicle is due for a test but is out of the area, you may apply for a waiver to delay testing.

If your business has a fleet of vehicles, contact an authorized tester. You may also test your own vehicles by becoming an authorized emission specialist through the training program. State and local government fleet vehicles are tested for free at test stations.

Testing isn't required for diesel vehicles that:

  • Are 2007 and newer models.
  • Have been equipped with an exhaust particle filter.
  • Weigh 6,000 pounds or less.

Find test station locations and other information about vehicle testing. 
Learn about the future of the emission check program. 

Clean Car Law

The Clean Car Law was passed in 2005. Cars, light duty trucks, and passenger vehicles (SUVs and passenger vans) manufactured after Jan. 1, 2009 must meet strict clean air standards to be registered, leased, rented, licensed, or sold in Washington. The law helps reduce air pollution and greenhouse gases.

Diesel exhaust is one of the most harmful air pollutants. Seventy percent of cancers caused by airborne pollutants come from diesel exhaust. It puts healthy people at risk for respiratory diseases and complicates health conditions for people with asthma, heart, and lung disease. Over four million people in Washington live and work where exposure to diesel exhaust is high. We are working to reduce diesel emissions and protect your health by helping fleet managers:

  • Reduce idling.
  • Use cleaner fuels.
  • Install equipment to clean up diesel exhaust (retrofitting).
  • Replace older engines with new, cleaner ones.
Read our "Engine Idling: Drive Smart" brochure for more ways to reduce vehicle pollution.

Volkswagen enforcement actions

Volkswagen violated federal and state clean air laws by installing illegal emissions software on some diesel vehicles. In January 2016, the Department of Justice, on behalf of EPA, filed a lawsuit against VW. After admitting fault, they reached multiple settlements with EPA and Washington.

Washington will receive $112.7 million from the federal settlement and $28 million from the state settlement. The funds will be used to reduce air pollution from transportation.