Pollutant Fact Sheets




Diesel exhaust is an air pollutant created when diesel fuel is burned.  It is a mixture of tiny particles and gases that includes fine particulate matter (PM2.5), nitrogen oxides, organic and elemental carbon, benzene, nickel, and formaldehyde.1  Diesel exhaust contributes to the formation of ozone (or “smog”), acid rain, and climate change.2 The amount, composition and toxicity of diesel exhaust emitted from a diesel engine depends on the engine (including its age, type and condition), whether the engine has pollution control equipment (e.g., particle traps), fuel type and quality (e.g., the amount of sulfur), and the engine load (e.g., acceleration).3


In Detroit, most diesel exhaust emissions come from “on-road” vehicles and “off-road” construction equipment powered by diesel engines.  Figure 1 shows the major sources in Wayne County.Picture1

“On-road” emissions occur mostly on highways and major roads, and heavy-duty trucks are the largest emitters.  Trucks crossing the Ambassador Bridge between Detroit and Windsor, Ontario are especially important since this is one of the busiest international commercial vehicle crossings in North America, with up to 13,000 trucks per day.4 Truck traffic at freight warehouses and railroad yards is also extensive.5 Trucks produce diesel exhaust emissions even while idling and queuing.

Diesel exhaust emissions from “off-road” sources are also important.  Major sources include construction equipment, cranes/loaders, trains, and ships. The engines in these sources can be old and high emitting.  Recent emission reduction regulations target older equipment, but the replacement or turnover of the fleet can be slow.

Figure 1: Emissions of diesel exhaust from major sources in Wayne County.  National Emissions Inventory data, 2011.


An estimated 280 deaths and 380 heart attacks occur each year in Detroit from exposure to diesel exhaust emissions.6  Exposure to diesel exhaust can cause many short term (acute) and long term (chronic) health effects, including:

  • Eye, nose, throat, and lung irritation7
  • Lightheadedness7
  • Aggravation of bronchitis1 and asthma1,7
  • Reduced growth of lungs8
  • Chronic respiratory symptoms8
  • Kidney damage9
  • High blood pressure9
  • Lung cancer 7, 10
  • Heart attacks8
  • Increased risk of mortality8



Diesel exhaust emissions are not directly monitored in outdoor air, and there is no ambient air quality air standard since diesel exhaust is a mixture of pollutants.  However, diesel exhaust forms a part of fine particulate matter, called PM2.5, which is monitored and regulated by the State of Michigan and the US Environmental Protection Agency.  Diesel exhaust emissions comprise about 20% of PM2.5 at several Detroit monitoring sites, and a larger amount at “hot spots.”11  While Detroit meets the national standards for PM2.5, reducing exposure to diesel exhaust remains a priority, particularly for exposed and susceptible individuals and near roadway “hot spots”.  (For more information, see CA-PHE’s PM fact sheet).


Residents living, working, or attending schools within about100 yards of highways, railroad yards, freight warehouses, and other locations where diesel engines are used are likely to experience higher exposure to diesel exhaust emissions.8  This includes residents of Southwest Detroit, due to truck traffic from the Ambassador Bridge.  People living near busy surface streets and freeways are also at risk.

Certain individuals are more susceptible to adverse health effects from diesel exhaust.  Children are susceptible because their lungs are still developing, they breathe faster, have a lower body weight, and spend more time outdoors than adults.12  Adults older than 65 years of age, and people with heart or lung disease, asthma, or other respiratory problems are also more sensitive.13


  • Enact stronger emission standards for diesel engines, and lower air quality standards near highways
  • Modernize diesel buses, trucks, and locomotives, e.g., create and enforce engine rebuild/replacement requirements, and establish a Clean Truck Mitigation Fund14
  • Maintain buses and trucks, and retrofit older vehicles with pollution control devices like particulate traps10
  • Enforce Detroit’s anti-idling ordinance10,14 and reroute trucks outside residential communities15, 16
  • Enact zoning and planning regulation that separates emission sources from people by requiring new homes, medical facilities, daycare centers, schools, and playgrounds to be 500 or more feet from highways and busy roads14
  • Replace diesel engines at freight terminals with electrical motors
  • Equip homes with air filters and upgrade furnace filters, to lower exposure to pollutants that enter homes17
  • Use electrification programs at truck stops so truckers can power rigs overnight without running engines


  1. Michigan Department of Environmental Quality. 2010. Detroit Air Toxics Initiative. http://www.michigan.gov/deq/0,4561,7-135-3310_4105-139044–,00.html, accessed 1/27/14
  2. United States Environmental Protection Agency. Basic Information, National Clean Diesel Campaign. http://www.epa.gov/cleandiesel/basicinfo.htm, accessed 1/27/15
  3. Chin, JY, S Batterman, W.F. Northrop, S.V. Bohac, D.N. Assanis, “Gaseous and particulate emissions from diesel engines at idle and under load: comparison of a biodiesel blend and ultra low sulfur diesel fuels, Energy and Fuels, 26, 6737−6748, 2012. http://dx.doi.org/10.1021/ef300421h.
  4. Southeast Michigan Council of Governments, SEMCOG Information, The Ambassador Bridge,www.semcog.org/WorkArea/downloadasset.aspx?id=5369, accessed 10/14/14
  5. Hammond, Dvonch, et al. 2008 “Sources of ambient fine particulate matter at two community sites in Detroit, MI.” Atmospheric Environment, 42: 720–732
  6. Clean Air Task Force. Diesel and Health in America, The Lingering Threat. Boston, MA. www.catf.us/resources/publications/files/Diesel_Health_in America.pdf
  7. United States Environmental Protection Agency. Diesel Particulate Matter. http://www.epa.gov/region1/eco/airtox/diesel.html, accessed 10/14/14
  8. Clean Air Task Force. 2007. “No escape from diesel exhaust: how to reduce commuter exposure.” http://www.catf.us/resources/publications/files/No_Escape_from_Diesel_Exhaust.pdf, accessed 1/27/15
  9. Agency for Toxic Substances & Disease Registry, Toxic Substances Portal. Fuel Oils/Kerosene, Public Health Statement for Fuel Oils. http://www.atsdr.cdc.gov/phs/phs.asp?id=514&tid=91, accessed 10/14/14 .
  10. Department of Health and Human Services, National Toxicology Program. 2014. Report of Carcinogens, Thirteenth Edition. http://ntp.niehs.nih.gov/pubhealth/roc/roc13/index.html, accessed 1/27/15.
  1. Agency for Toxic Substances and Disease Registry. Your Child’s Environmental Health: How the Body Works: Differences Between Adults and Children. https://michigan.gov/documents/ATSDRChildrens Health handouts FS_155917_7.pdf, accessed 10/14/14
  2. Michigan Department of Environmental Quality, Air Quality Division, 2008. State Implementation Plan Submittal for Fine Particulate Matter (PM2.5) – Appendix G: Overview of Recent Detroit PM Source Apportionment Studies. http://www.michigan.gov/documents/deq/deq-aqd-air-aqe-Appendix-G-Detroit-PM-Source-Apportionment_238078_7.pdf. Accessed Jan. 4, 2015.
  3. American Cancer Society. 2014. Diesel Exhaust. www.cancer.org/cancer/cancercauses/othercarcinogens/pollution/diesel-exhaust
  4. The Trade, Health, and Environment Impact Project. 2012. “Driving harm: health and community impacts of living near truck corridors.” The Impact Project Policy Brief Series.
  5. Karner, A., Eisinger D., et al. 2008. “Mitigating diesel truck impacts in environmental justice communities: transportation planning and air quality in Barrio Logan, San Diego.” The UC Davis-Caltrans Air Quality Project. http://www.dot.ca.gov/hq/env/air/research/ucd_aqp/Documents/Mitigation-Measures-Package-Report-4-Alex-v3.pdf, accessed 11/17/14
  6. Gonzalez, P.A., Minkler, M., et al. 2011. “Community-based participatory research and policy advocacy to reduce diesel exposure in West Oakland, California.” American Journal of Public Health, 101 (S1); S166-S175
  7. Du, L., Batterman,S. et al. “Particle concentrations and effectiveness of free-standing air filters in bedrooms of children with asthma in Detroit, MI.” Building and Environment, 46, 2303-2313,2011. http://dx.doi.org/10.1016/j.buildenv.2011.05.012