Fact Pack

Diesel – A Known and Well-Researched Health Risk

• Even though Americans spend an average of between 80-90% of their time indoors or in vehicles, air quality in buildings and vehicles is not regulated by the U.S. Environmental Protection Agency (EPA) or many states.(1)
• Diesel exhaust is classified as a probable human carcinogen by many governmental authorities, including the International Agency for Research on Cancer (IARC), the U.S. National Toxicology Program, and the U.S. Environmental Protection Agency.(1)
• Since 1990, diesel exhaust has been listed as a known carcinogen under California’s Safe Drinking Water and Toxic Enforcement Act (Proposition 65) and, since 1998, as a toxic air contaminant.(2)
• Studies in California reveal that more than 70% of the risk of cancer from ambient air pollution comes from diesel exhaust alone.(2)(3)
• Diesel exhaust as well as many of its constituents is carcinogenic. The following substances are among the hundreds of chemicals present in diesel exhaust. Most of these substances are listed as Hazardous Air Pollutants by the EPA.(4)

Diesel Exhaust and Particulates Most Severely Affects Children

• Today, approximately 99% of the nation’s 600,000 school buses run on diesel fuel – buses that are responsible for bringing 24 million children to school each day.(1)
• Between 1980 and 1994 the incidence of asthma among young children increased by 160 percent.(5) Children make up only 25 percent of the national population, but account for about 40 percent of U.S. asthma cases.(6)
• According to the Natural Resources Defense Council (NRDC), children constitute one of the most susceptible groups to adverse health effects from diesel, due to children’s “developing body and lungs, narrower airways, faster metabolism, and faster breathing rate than adults.”(2)
• Diesel particulates are dangerous because they are so tiny, and can lodge into the deepest areas of human lungs. Children, in particular, are susceptible because they breathe 50 percent more air per pound of body weight than adults.(6)
• A 2000 study by the University of Southern California Keck School of Medicine found a correlation between both NOx and particulate pollutants and a potentially significant decrease in lung function growth among children in southern California.(7)
• Based on their 2001 study, NRDC estimates that, “for every one million children riding the school bus for 1 or 2 hours each day during the school year, 23 to 46 children may eventually develop cancer from the excess diesel exhaust they inhale on their way to and from school. This mean s a child riding a school bus is being exposed to as much as 46 times the cancer risk considered ‘significant’ by EPA and under federal law.”(2)
• According to the State and Territorial Air Pollution Program Administrators and the Association of Local Air Pollution Control Officials, more than 125,000 cancer cases in the United States are attributable to diesel exhaust.(8)

Cost-effective, Viable Alternatives to Traditional Diesel

• In January 2001, the EPA finalized plans to reduce sulfur content in on-road diesel fuel by 97 percent, beginning in 2007. The phase out would reduce sulfur levels from today’s 500 parts per million (ppm) to 15 parts per million (ppm). The EPA estimates that the new rules will reduce nitrogen oxide emissions by 2.6 million tons and particulate matter by 111,000 tons annually. It would also prevent an estimated 8,300 premature deaths, 5,500 cases of chronic bronchitis, and 17,600 cases of acute bronchitis in children annually. In addition, the EPA predicts the rules will help avoid more than 360,000 asthma attacks and 386,000 cases of respiratory symptoms in asthmatic children every year. Obviously, reducing sulfur content on a national scale is a effective way to reduce pollution and health hazards nationwide.(9)
• In addition to reducing the sulfur content of diesel fuel, biodiesel fuel or biodiesel blends are viable alternatives to traditional diesel. Biodiesel is a domestically- produced, renewable fuel that is safe, biodegradable, and reduces serious air pollutants such as soot, particulates, carbon monoxide, hydrocarbons, and air toxics. Tests have shown that twenty percent biodiesel blends reduce the cancer-causing potential of diesel particulate matter by 27%; for pure biodiesel, the reduction increases to 94 percent. The new EPA regulations specifically require reductions in particulate matter, nitrogen oxides, and hydrocarbons, so the biodiesel alternative would be a way of addressing impending regulation. Regulated fleets can also earn Energy Policy Act credits by purchasing biodiesel fuel.(10)
• In addition to biodiesel, liquefied and compressed natural gas (LNG & CNG), liquefied petroleum gas (LPG or propane), battery-electric, and synthetic diesel derived from natural gas (Fischer-Tropsch diesel) are all alternatives to petroleum diesel. Other alternative fuels such as hydrogen and fuel cells are still under development and are expected to be available within the next ten to twenty years. Natural gas is currently the best, most-developed alternative to petroleum. It can be produced in North America and is available in combination with diesel and, better yet, in combination with battery electric power. However, natural gas, just like petroleum and coal, is a non-renewable fossil fuel, so it also contributes to global warming and will some day be used up unless we use multiple alternative fuel sources.
• Finally, older diesel engines can be retrofitted to reduce emissions until vehicles can be replaced with newer, cleaner burning ones. There are a variety of retrofits that vary in expense and effectiveness, but most can reduce current particulate matter and NOx emissions by up to 90 percent.(11) For particular information and comparisons of different techniques and technologies, see the Clean Air Task information page on “Emissions Controls and Retrofits.”

Sources:
(1) Wargo, John. “Children’s Exposure to Diesel Exhaust on School Buses.” North Haven, Connecticut: Environment & Human Health, Inc., 7 February 2002. 29 April 2004 <http://www.ehhi.org/reports/diesel/>.
(2) Solomon, Gina M., et al. “No Breathing in the Aisles: Diesel Exhaust Inside School Buses.” National Resources Defense Council and the Coalition for Clean Air. January 2001 27 April 2004 <http://www.nrdc.org/air/transportation/schoolbus/sbusinx.asp>.
(3) Nazemi, Mike A. “Multiple Toxics Exposure Study (MATES-II) in the South Coast Air Basin.” U.S. Environmental Protection Agency, Office of Science Policy (OSP), South Coast Air Quality Management District. Sampling Period: April 1998 to March 1999. 29 April 2004 <http://www.epa.gov/osp/presentations/airtox/nazemi.pdf>.
(4) “Original list of hazardous air pollutants.” U.S. Environmental Protection Agency, Air Toxics Website. Last updated on Friday, January 9th, 2004. 29 April 2004 <http://www.epa.gov/ttn/atw/188polls.html>.
(5) Mannino, David M., et al. “Surveillance for Asthma – United States, 1960-1995.” Morbidity and Mortality Weekly Report (MMWR) 47.SS-1MMWR (24 April 1998). U.S. Department of Health and Human Services, Centers for Disease Control and Prevention (CDC). 29 April 2004 <http://www.cdc.gov/mmwr/PDF/SS/SS4701.pdf>.
(6) “Health and Environmental Effects of Particulate Matter.” U.S. Environmental Protection Agency, Office of Air & Radiation (OAR), Office of Air Quality Planning & Standards. 17 July 1997. Last updated on Thursday, July 11th, 2002. 29 April 2004 <http://www.epa.gov/ttn/oarpg/naaqsfin/pmhealth.html>.
(7) Gauderman, W. James, et al. “Association between Air Pollution and Lung Function Growth in Southern California Children.” American Journal of Respiratory and Critical Care Medicine 162.4, October 2000: 1383-1390. 29 April 2004 <http://ajrccm.atsjournals.org/cgi/content/full/162/4/1383>.
(8) State and Territorial Air Pollution Program Administrators and the Association of Local Air Pollution Control Officials. “Cancer Risk from Diesel Particulate: National and Metropolitan Area Estimates for the United States.” 15 March 2000. 29 April 2004 <http://www.4cleanair.org/comments/Cancerriskreport.PDF>.
(9) Milbourn, Cathy. “EPA Gives the Green Light on Diesel-Sulfur Rule.” 28 February 2001. U.S. Environmental Protection Agency. Last Revised: 02/28/2001. 29 April 2004 <http://yosemite.epa.gov/opa/admpress.nsf/b1ab9f485b098972852562e7004dc686/
0237f756e256922c85256a010072e4f6?OpenDocument>.
(10) U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy, Alternative Fuels Data Center. “Biodiesel Offers Fleets a Better Alternative to Petroleum Diesel.” May 2001. 29 April 2004 <http://www.afdc.nrel.gov/pdfs/Biodiesel_fs.pdf>.
(11) “Diesel Engines: Emissions Controls and Retrofits.” Clean Air Task Force. 29 April 2004 <http://www.catf.us/publications/fact_sheets/diesel/Diesel_Controls_and_Retrofits.pdf>.