Diesel fuel is a driving force in our state and national economy. The engines it powers - ranging from those in heavy trucks and school buses to boats and locomotives to construction equipment and emergency generators - touch our lives every day.

According to the Department of Environmental Protection (MassDEP) Massachusetts 2002 Diesel Particulate Matter Inventory, some 680,000 diesel engines operating in the state released an estimated 4,000 tons of fine particle pollution (solid particles and liquid droplets smaller than 2.5 microns in size, known as PM2.5). These engines powered approximately:

  • 600,000 diesel passenger cars, 18-wheelers, school and transit buses, delivery trucks, and other on-road diesel engines
  • 72,000 engines used in construction and mining, logging, agricultural, and several other groups of off-road, land-based equipment
  • 10,000 diesel passenger vessels, recreational boats, freight vessels, and other domestic marine engines
  • 1,000 emergency back-up generators used to power buildings
  • 140 diesel commuter rail engines and regional and national freight train lines

On- and off-road, land-based engines accounted for most diesel-related PM2.5 pollution in Massachusetts: 89 percent of the total. Marine and locomotive engines emitted 6 percent and 4 percent, respectively. Emergency generators emitted less than 1 percent.

Unfortunately, exhaust from diesel engines can have significant impacts on our health and environment. Breathing in even small amounts of diesel exhaust over extended periods of time can lead to serious health effects, especially for children, the elderly and the chronically ill. The U.S. Environmental Protection Agency (EPA) has determined that PM2.5 is likely to cause cancer and contribute to lung damage and cardiovascular disease. Short-term exposure to diesel exhaust can cause respiratory distress and worsen asthma, bronchitis and existing allergies.

Pollution from diesel engines also has a variety of environmental effects, from regional haze that obscures scenic vistas to climate change.

Although Massachusetts narrowly meets the federal air quality standard for fine particles, 25 counties in Connecticut, New Jersey and New York do not and pollution from those states can be transported here on prevailing winds.