FAQs • Puget Sound Clean Air Agency, WA • CivicEngage

What are the main sources of diesel exhaust?

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

Maritime vessels/ships and equipment generate 23% 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.
Off-road equipment generates 39% 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% of our region’s diesel exhaust. This sector includes cars, trucks, vans, buses, waste haulers, and emergency-response vehicles.
Rail generates 3% 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.

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Diesel Exhaust & Your Health

1. What are the health effects of diesel exhaust?: Diesel exhaust represents 78% 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.

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

Maritime vessels/ships and equipment generate 23% 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.
Off-road equipment generates 39% 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% of our region’s diesel exhaust. This sector includes cars, trucks, vans, buses, waste haulers, and emergency-response vehicles.
Rail generates 3% 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.

3. How are diesel emissions being reduced?: A combination of regulatory and voluntary measures are underway to reduce diesel emissions from the transportation sectors. This includes our Diesel Solutions program, and working with regional, national and international partners.