How Does Air Get Polluted?

Exhaust fumes contribute to serious human and wildlife illnesses.

Exhaust fumes contribute to serious human and wildlife illnesses.

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Air pollution is related to human illnesses like neurological, respiratory and reproductive disorders. It can harm wildlife health and the environment. Although some occurs naturally, most pollutants enter the air through human activities. The U.S. Environmental Protection Agency helps regulate many air pollutants, including six criteria pollutants. Criteria pollutants are so-named because regulations for their control are made with scientific human health and environmental welfare criteria as a guide. (See References 1 and 2)

Carbon Monoxide and Nitrogen Oxides

Consider public transportation and carpooling to help reduce two major pollutants. Vehicles are the largest producers of carbon monoxide and nitrogen oxide, which are two criteria pollutants (see References 3). Carbon monoxide reduces the amount of oxygen available to breathe. It is odorless and colorless, making it very dangerous to humans (see References 4). Nitrogen oxide is a component of ground-level ozone, which is responsible for many respiratory illnesses, especially in children, the elderly and people with diseases of the lungs (see References 5).

Sulfur Oxides and Nitrogen Oxides

Reducing the amount of electricity you use can help reduce pollutants and the resulting acid rain. Americans are dependent on electricity, and most electricity in this country is produced at power plants that burn coal. Power plants are the largest source of sulfur dioxide and a significant source of nitrogen oxide, which are components of acid rain. Solar, wind and hydro-electric power are alternatives to the polluting methods used to produce electricity. Because they do not burn fuels to produce energy, they do not produce any measurable amounts of pollution. (See references 6)

Volatile Organic Compounds

Vehicles and solvents are significant sources of volatile organic compounds, or VOCs (see References 7). When VOCs and nitrogen oxides combine in the air on a hot, sunny day, ground-level ozone is created. It is a harmful chemical, even though it has the same chemical makeup as the ozone in the stratosphere that protects the earth from solar radiation. (See References 3)


Landfills release concentrated amounts of methane, a greenhouse gas, into the air. Many scientists associate greenhouse gases with global warming. Although it is not a criteria pollutant, it is significant because of the harm greenhouse gases create. (See References 8) Reducing the amount of trash you throw away can help lower methane levels and vehicle emissions from waste transport trucks. Instead of tossing unwanted things into a trash can, consider each item's potential for being repurposed, repaired or recycled. Recycle grass clippings, leaves and vegetable peelings into compost. Send paper, glass and aluminum cans to a recycling center. If a broken device cannot be repaired, its components might be useful for repairing something else. For each thing you could send to a landfill, try to find an alternative destination.

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Lee Carroll


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