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Air Quality Program

Diesel Information

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The Washington State Department of Ecology (Ecology) has identified diesel exhaust as the air pollutant most harmful to public health in Washington State. Seventy percent of the cancer risk from airborne pollutants is from diesel exhaust. It puts healthy people at risk for respiratory disease and worsens the symptoms of people with health problems such as asthma, heart disease, and lung disease. More than four million people in Washington live or work close to highways and other major roads where they are most likely to be exposed to diesel exhaust.


How is Ecology reducing diesel emissions?

Ecology is working to reduce diesel emissions by providing assistance to help fleet managers to reduce idling, use cleaner fuels, install equipment to clean up diesel exhaust (called “exhaust retrofits”), and replace older engines with newer, cleaner ones.

The links below give more detailed information about diesel exhaust and efforts to reduce diesel emissions.

Reducing Idling

School bus Information

Cleaner Diesel Fuel

As of 2006, almost all petroleum-based diesel fuel available in the US is ultra low sulfur diesel (ULSD). Burning ULSD substantially lowers emissions of particulate matter from diesel engines


What are others doing to reduce diesel exhaust emissions?

Here are some examples from programs across the country: