Section 25.2 Air Quality and Health Objectives Summarize the potential health effects of air pollution. Evaluate factors that affect indoor air pollution. Analyze how government and personal actions can help improve air quality.

Dear Advice Line, My allergies always seem to be worse when I am indoors rather than outdoors. I thought flowers and other things found outdoors caused allergies. Is something wrong with me? Make a list of indoor conditions that might affect indoor air quality. Then, write back with your answer and advice.

Air Pollution Pollution is the presence or release of substances—called pollutants—into the environment in quantities that are harmful to living organisms. Air pollutants can damage the respiratory system, enter the bloodstream and harm other parts of the body, and reduce your protection from the sun’s radiation. One of the biggest sources of air pollution is the burning of fossil fuels, energy-rich substances mined from deep in the earth. Harmful gases also are released into the air when liquids such as gasoline or paint thinner evaporate, or when gases are released from natural sources such as volcanoes.

What Is Smog? Smog is a brown haze that forms when air pollutants react in the presence of sunlight. It forms when there is little or no wind and a layer of air is trapped next to the ground. Without air circulation, pollutants can build up and become visible as smog.

Air Pollutants and the Ozone Layer Naturally occurring ozone located high up in earth’s atmosphere—in the ozone layer—plays a protective role. The ozone layer absorbs most of the harmful ultraviolet light radiated by the sun, thus preventing it from reaching Earth’s surface. Some air pollutants destroy the ozone layer. Chemicals called CFCs, short for chlorofluorocarbons (klawr oh floor oh KAHR bunz) are especially damaging.

Indoor Air Pollution Indoor air pollution is most severe in homes and other buildings that have been sealed against air leaks. Inside energy-efficient buildings, pollutants can build up to high levels if the air is not conditioned properly.

Asbestos Many older buildings contain a dangerous indoor pollutant called asbestos. Asbestos (as BES tus) is a fibrous mineral that was used in fireproofing and other building materials. When asbestos fibers are inhaled into the lungs, they damage the cells of the lungs and can cause lung cancer.

Radon A naturally occurring radioactive gas called radon is also a serious indoor air pollutant. Radon leaks from rocks in the ground through the foundations of buildings. Radon is responsible for about 5,000 to 20,000 deaths from lung cancer each year.

For: Updates on health effects of air pollution Click above to go online.

Protecting Air Quality Governments passed regulations to reduce emissions of harmful gases from motor vehicles and industries. In addition to government regulations, personal actions, such as your day-to-day decisions about energy use, directly affect air quality.

Government Regulations The Clean Air Act of 1970 identified major air pollutants and set standards for air quality. Since 1970, Congress has made changes and additions to the Clean Air Act every few years. Some other federal and local government measures that help reduce air pollution include funding for developing more efficient ways to use traditional fossil fuels or alternatives to these fuels, such as wind power and solar power laws requiring vehicles to pass annual inspections of exhaust pollutants tax breaks for drivers who purchase hybrid automobiles that save gasoline by running partly on electric power

Air Quality Ratings Weather reports for cities and other areas with air pollution problems often include air quality ratings. The ratings, which are based on air quality standards set by the government, range from “good” to “unhealthy” to “very hazardous.”

What You Can Do Walk, ride a bicycle, or use public transportation instead of an automobile. When driving, avoid unnecessary trips. Make sure your vehicle is well-maintained so it produces the least pollution. Turn off lights and appliances that are not being used. Clean the cooling fans or coils on refrigerators and air conditioners so they will work efficiently. In winter, set the thermostat lower and wear extra clothes to keep warm indoors. In the summer, if you have an air conditioner, set it at the highest comfortable temperature.

Vocabulary pollution The presence or release of substances into the environment in quantities that are harmful to living organisms. fossil fuels Energy-rich substances mined from deep in the earth, including coal, oil, and natural gas. smog A brown haze that forms when air pollutants react in the presence of sunlight. ozone layer A section of the atmosphere that contains naturally occurring ozone; absorbs ultraviolet light from the sun.

Vocabulary asbestos A fibrous mineral that was once used in fireproofing and other building materials; asbestos fibers can cause lung disease. radon A naturally occurring radioactive gas that is a serious indoor air pollutant.

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End of Section 25.2 Click on this slide to end this presentation.