Vehicles and equipment powered by diesel engines account for more than two-thirds of all particulate matter (PM) emissions.
Diesel particulate matter (DPM) or soot is created during the incomplete combustion of diesel fuel. It includes hundreds of chemical elements, including sulfates, ammonium, nitrates, elemental carbon, condensed organic compounds, carcinogenic compounds and even heavy metals such as arsenic, selenium, cadmium, and zinc. Particulate matter varies in size from less than 10 microns in diameter to fine particulates, less than 2.5 microns and finally, ultrafine particulates that are less than 0.1 microns. Ultrafine particulates, make up 80-95% of diesel soot pollution.
Diesel particulate matter causes irritation to eyes, nose, throat, and lungs and contributes to cardiovascular and respiratory illness and premature death. Individuals with preexisting respiratory conditions, children and the elderly are the most vulnerable to diesel particulate matter. It is estimated that as a result of particulate pollution in the US, tens of thousands of people die prematurely each year.
The U.S. Environmental Protection Agency (EPA) has classified diesel exhaust as a potential human carcinogen. Studies of people exposed to diesel fumes routinely indicate a higher risk of lung cancer. According to studies of railroad, dock, trucking and bus workers, to name a few, the workers exposed to high levels of diesel exhaust demonstrated a 20 to 50 percent increase in the risk of lung cancer or mortality.