Diesel 

WHAT IS DIESEL EXHAUST?

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 (PM_2.5), 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

WHERE DOES DIESEL EXHAUST COME FROM?

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.

“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.

HOW DOES DIESEL EXHAUST AFFECT YOUR HEALTH?

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 asthma^1,7
• Reduced growth of lungs⁸
• Chronic respiratory symptoms⁸
• Kidney damage⁹
• High blood pressure⁹
• Lung cancer ^{7, 10}
• Heart attacks⁸
• Increased risk of mortality⁸

IS DETROIT’S AIR HEALTHY?

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 PM_2.5, which is monitored and regulated by the State of Michigan and the US Environmental Protection Agency.  Diesel exhaust emissions comprise about 20% of PM_2.5 at several Detroit monitoring sites, and a larger amount at “hot spots.”¹¹  While Detroit meets the national standards for PM_2.5, 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).

WHO IS MOST LIKELY TO BE AFFECTED?

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

HOW TO REDUCE AND AVOID EXPOSURE TO DIESEL EXHAUST

• 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 ordinance^10,14 and reroute trucks outside residential communities^{15, 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