Why is diesel exhaust important along the West Coast?

The West Coast, like other parts of the country, suffers from high concentrations of diesel exhaust, which exacerbates and possibly causes respiratory and cardiovascular illness and is a likely human carcinogen. The West Coast also contains a unusual convergence of many different types of diesel sources – from diesel trucks traveling along the I-5 corridor, to diesel-powered marine vessels and trains along the Pacific coast, to diesel agricultural equipment in the most agriculturally productive region in the country, to diesel construction equipment operating in some of the fastest growing cities in the country.

What are the health impacts of diesel exhaust?

Diesel exhaust is a clear public health concern. Emissions from diesel engines contribute to unhealthy levels of fine particles and ozone (or “smog”) as well as air toxics. Fine particles have been associated with an increased risk of premature mortality, hospital admissions for heart and lung disease, increased respiratory symptoms and other adverse effects. Long-term exposure to diesel exhaust may pose a lung cancer hazard to humans at ambient concentrations.

Ozone can irritate the respiratory system and can reduce lung function, making it more difficult to breathe deeply, thereby limiting a person’s normal activity. Ozone can also aggravate asthma and other respiratory diseases, leading to more asthma attacks, greater use of additional medication, more severe symptoms that require a doctor’s attention, more visits to the emergency room, and increased hospitalizations.

Who is most at risk?

People with existing heart or lung disease, asthma, or other respiratory problems are most sensitive to the adverse health effects of fine particles and ozone. Children and the elderly are also sensitive. Children are especially at risk from air pollution in general because they breathe 50 percent more air per pound of body weight than adults.

Reducing diesel exposures is associated with reductions in the incidence and severity of asthma attacks and chronic bronchitis. It will decrease the number of lost school days for children and work days for parents and adult asthmatics.

What are the environmental concerns with diesel exhaust?

Fine particles in diesel exhaust contribute to haze, which restricts visibility. Diesel exhaust also contributes to ozone formation (ozone is a component of smog), acid rain. Moreover, unnecessary idling of diesel engines wastes fuel and contributes to global climate change.

What is being done to reduce diesel exposures?

Diesel emissions are regulated by state, federal and local governments. For on-road sources in December 2000 and for non-road sources in May 2004, EPA announced comprehensive rules to reduce emissions from diesel engines by integrating engine and fuel controls as a system to gain the greatest emission reductions. In 2030, when fully implemented, these rules will achieve over $100 billion in health benefits. However, these exhaust emission standards apply only to newly manufactured engines. Diesel engines may last up to 30 years and the approximately 11 million engines in-use today can be made cleaner with the application of existing innovative emission control technology and the use of cleaner fuels. The Collaborative is working to bring about these air quality benefits sooner.

More Information

For more information about the West Coast Collaborative please contact Peter Murchie, murchie.peter@epa.gov or Michelle Roos, roos.michelle@epa.gov.

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