Puget Sound Clean Air Agency
Photo: diesel truck idling with dark exhaust visibleLogo: Diesel Solutions

Diesel Exhaust & Your Health


Why is diesel exhaust harmful?

Diesel exhaust, or diesel particulate matter (DPM), is composed of harmful fine particles and air toxics. Fine particles are very tiny particles that bypass the immune system and proceed into your lungs, which can cause serious health effects. Air toxics are a group of over 400 pollutants known or suspected to cause significant health risk. Click to learn more about fine particles and air toxics.

What are the health effects of diesel exhaust?

Diesel exhaust represents 78 percent of the potential cancer risk from all air toxics in the Puget Sound area. It is also linked to respiratory and cardiovascular problems, and premature death. Children, the elderly, pregnant women, and those with compromised immune systems or illnesses are especially vulnerable. Recent studies show people living near ports and roadways have higher exposures and health risk.

Air Toxics cancer pie chart

What are the main sources of diesel exhaust?

The majority of diesel exhaust in the Puget Sound region comes from four transportation sectors:

Diesel Exhaust

Off-road equipment generates 39 percent of our region’s diesel exhaust. This sector includes construction equipment, aircraft-support equipment, and cargo-handling equipment* used at seaports and rail yards.
*Note: For emissions inventory purposes, our agency includes cargo-handling equipment as part of the maritime sector and not the off-road sector.

On-road vehicles generate 34 percent of our region’s diesel exhaust. This sector includes cars, trucks, vans, buses, waste haulers, and emergency-response vehicles.

Maritime vessels/ships and equipment generate 23 percent of our region’s diesel exhaust. This sector consists all ocean-going and harbor vessels, as well as all marine/seaport-related activities, such as drayage trucks, switchyard locomotives, and cargo-handling equipment.

Rail generates 3 percent of our region’s diesel exhaust. This sector consists of locomotives that transport goods and people, as well as those that sort cargo within a rail yard.

How are diesel emissions being reduced?

A combination of regulatory and voluntary measures is underway to reduce diesel emissions from the transportation sectors. This includes our Diesel Solutions program, and working with regional, national and international partners. Visit our Partners page to learn more.

You can help clean the air too. Click here to learn how driving less, opting for a cleaner fuel or vehicle, and not idling can reduce pollution, save money, and protect health.


Air toxics


Fine particles