Urban Environmental Quality and Human Health: Conceiving a Sustainable Future

Overview

For many years, air pollution was viewed as a visual nuisance. But as the twentieth century progressed, our understanding of air pollution evolved considerably. As a result of several highly publicized air pollution events, including the Donora, Pennsylvania fog, where 17 people died and nearly half the town's 14,000 residents became sick from a severe air pollution episode in 1948, researchers began to acknowledge that air pollution was a significant threat to public health.

On November 18, 1994, the first-ever conference on "Air Pollution: Impacts on Body Organs and Systems" was held in Washington, D.C. by the National Association of Physicians for the Environment:

"Blood perfuses all of the body's organs and can carry toxic substances as well as beneficial substances, such as oxygen, to them. Air pollution is the source of many materials that may enter the human bloodstream through the nose, mouth, skin, and the digestive tract, containing chemicals known to be harmful, such as benzene, lead and other heavy metals, carbon monoxide, volatile nitrites, pesticides, and herbicides. These substances have been shown to produce harmful effects on the blood, bone marrow, spleen, and lymph nodes.²"

Air pollution can be caused by the release of small particles or noxious gases being released into the atmosphere, whether by natural or fabricated sources. These gases include carbon monoxide, sulfur dioxide, nitrogen oxide, and chemical vapors, as well as others. The gases can also lead to a chain-reaction event that includes acid rain, smog, and the greenhouse effect. If left unchecked, the chemical aspect of air pollution could become the largest contributor to premature death in the world, higher than the rate of cancer, AIDS, automobile accidents, or any other cause of unnatural or premature death.³ Most people make the assumption that the greatest single cause of air pollution is the big factories that dot our landscape, especially in our big cities; however, the greatest single contributor to the pollution problem facing not only the United States but also the entire world is automobile emissions ⁴ which come mainly from cars and other types of automobiles, as well as off-road vehicles.

Transportation caused over half of the carbon monoxide, over a third of the nitrogen oxides, and almost a quarter of the hydrocarbons in ouratmosphere in 2006.⁵ With the number of vehicles on the road and the number of vehicle miles traveled escalating rapidly, we are on the fast road to uncontrollable air pollution. These "mobile sources" include cars, motorcycles, and light trucks, heavy trucks and buses, nonroad recreational vehicles (such as dirt bikes and snowmobiles), farm and construction machines, lawn and garden equipment, marine engines, aircraft, and locomotives.⁶ Table 1 below lists six different air pollutants monitored by the EPA, and reiterates the excessive amounts for which transportation is responsible, as well as separating highway and local driving habits.

Table 1: Transportation's Percent Share of Air Pollutants; Highway vs. Non-Highway

Table information can be found in Transportation Energy Data Book7.

Emissions from passenger vehicles are increasing in Canada and the U.S. despite attempts to make engines more fuel efficient and despite the addition of antipollution devices. Several reasons are; vehicle use has increased, cars are getting bigger as pick-up trucks, vans and sports vehicles, which burn more fossil fuel per mile, are often replacing smaller, lighter passenger cars, recreational vehicles using combustion engines are not regulated for air pollution, and vehicular modes of transport have increased across the country. Exhaust from all combustion engines combine to produce local adverse effects on the health of car users and all innocent bystanders. Table 2 below lists four pollutants monitored by the EPA, and separates them by type of fuel used, and local vs. long-distance driving. Cities have become islands of toxic chemicals from the unrestrained use of vehicles burning fossil fuels, with millions of short tons of pollution created by vehicle exhaust.

Table 2: Amount of Air Pollutants; Highway vs. Non Highway, Petrol vs. Diesel Vehicles

Table information can be found in Transportation Energy Data Book.⁸

Emissions causing air pollution are associated with the full life-cycle of cars, buses, motorcycles, off-road vehicles, and trucks. This includes air pollution emitted during the refining and distribution of vehicle fuel, vehicle operation, refueling, and disposal, in the piecemeal manufacturing process, in the construction of the car itself within the factory, and within the vehicle itself from the carpeting, air conditioning system, leaks from the exhaust, and the fabrics and plastics used within the car. Therefore, motor vehicles cause both primary pollution, emitted directly into the atmosphere, and secondary pollution, resulting from chemical reactions between pollutants in the atmosphere. There are numerous ways that vehicles are linked to air pollution. The use of CFCs (chlorofluorocarbons) in car air-conditioning systems has contributed to the destruction of the earth's ozone layer, as cars leak about 1 pound of coolant a year. Tires, brakes, clutch linings are all made of, and leak into the air; lead, asbestos, and cadmium, all of which are toxic to humans and animals. Old oil from car engines that is dumped on the ground instead of being properly disposed of contaminates the environment. Just 1 quart of oil can contaminate 250,000 gallons of drinking water.⁹ The amount of oil improperly dumped every 2.5 weeks in the U.S. equals the total amount lost in the Valdez spill,¹⁰ with 250 million gallons a year of oil improperly discarded, and each year, 176 million gallons enter the storm sewers. The tars and other organic compounds released in the smoke from automobiles also pollute the atmosphere, and, when they land on the ground, pollute the soil and can potentially enter the groundwater and drinking supply.

Not all pollution produced by cars is the same; there are two types of pollution discharged by petrol vehicles. These include; evaporative emissions, which occurs when vapors of fuel are released into the atmosphere, without being burnt, and exhaust emissions, including dangerous gases such as carbon monoxide, oxides of nitrogen, hydrocarbons and particulates.¹¹ The major pollutants are particulate matter, hydrocarbons, nitrogen oxides, carbon monoxide, sulfur dioxide, hazardous air pollutants, and greenhouse gases, all of which are extremely dangerous for humans. Others associated with the full life cycle include polychlorinated biphenyls, a.k.a. PCBs, which is a mix of about 70 chemicals, including C, H, and Cl. PCBs were manufactured in the U.S. from 1929-1979 for inks, hydraulic fluids, adhesives, graphites, and lubricants, so was used in many places within the manufacture of a car. As an example of the danger of these chemicals to humans, in 1968 and again in 1979, people in the orient used rice oil that was contaminated by PCBs, and widespread liver and kidney damage ensued. It was banned in 1979 but large amounts had been dumped improperly and still are found in old electrical equipment.