(4) Air Pollution

Indoor Air Pollution: The Silent Killer


Indoor Air Pollution Is a Serious Problem

If you are read one book indoors, you may be inhaling more air pollutants than you would if you were outside. Indoor air pollution usually poses a much greater threat to human health than does outdoor air pollution. EPA studies have revealed some alarming facts about indoor air pollution in the United States and in other developed countries. First, levels of 11 common pollutants generally are two to five times higher inside homes and commercial buildings than they are outdoors, and as much as 100 times higher in some cases. Second, pollution levels inside cars in traffic-clogged urban areas can be as much as 18 times higher than out- side levels. Third, the health risks from exposure to such chemicals are magnified because most people in developed countries spend 70–98% of their time indoors or inside vehicles.

Since 1990, the EPA has placed indoor air pollution at the top of the list of 18 sources of cancer risk. It causes as many as 6,000 premature cancer deaths per year in the United States. At greatest risk are smokers, infants and children younger than age 5, the old, the sick, pregnant women, people with respiratory or heart problems, and factory workers.

Danish and U.S. EPA studies have linked various air pollutants found in buildings to a number of health effects, a phenomenon known as the sick-building syndrome (SBS). Such effects include dizziness, headaches, coughing, sneezing, shortness of breath, nausea, burning eyes, chronic fatigue, irritability, skin dryness and irritation, flu-like symptoms, and depression. EPA and Labor Department studies indicate that almost one in five commercial buildings in the United States is considered “sick,” exposing employees to these health risks.


GREEN CAREER: Indoor air pollution specialist According to the EPA and public health officials, the four most dangerous indoor air pollutants in developed countries are tobacco smoke; formaldehyde found in many building materials and household products; radioactive radon-222 gas; and very small particles. Formaldehyde, a colorless, extremely irritating organic chemical, is a growing problem. According to the EPA and the American Lung Association, 20–40 million Americans suffer from chronic breathing problems, dizziness, rash, headaches, sore throat, sinus and eye irritation, skin irritation, wheezing, and nausea caused by daily exposure to this chemical.

In developing countries, the indoor burning of wood, charcoal, coal, and other fuels for cooking and heating in open fires or in unvented or poorly vented stoves exposes people to dangerous levels of particulate air pollution. According to the WHO and the World Bank, indoor air pollution for the poor is by far the world’s most serious air pollution problem.

 Your Respiratory System Helps Protect You from Air Pollution

Your respiratory system helps protect you from air pollution. Hairs in your nose filter out large particles. Sticky mucus in the lining of your upper respiratory tract captures smaller (but not the smallest) particles and dissolves some gaseous pollutants. Sneezing and coughing expel contaminated air and mucus when pollutants irritate your respiratory system. In addition, hundreds of thousands of tiny mucus coated hair like structures called cilia line your upper respiratory tract. They continually wave back and forth and transport mucus and the pollutants they trap to your throat where they are swallowed or expelled. Prolonged or acute exposure to air pollutants, including tobacco smoke, can overload or break down these natural defenses. Years of smoking and breathing air pollutants can lead to lung cancer and chronic bronchitis.

Damage deeper in the lung can cause emphysema, in which irreversible damage to air sacs or alveoli leads to abnormal dilation of air spaces, loss of lung elasticity, and acute shortness of breath.

 Air Pollution Is a Big Killer

According to the WHO, at least 3 million people worldwide (most of them in Asia) die prematurely each year from the effects of air pollution—an average of 8,200 deaths per day. About 2.2 million of these deaths (73%) result from indoor air pollution, typically from heart attacks, respiratory diseases, and lung cancer related to daily breathing of polluted air. In the United States, the EPA estimates that annual deaths related to indoor and outdoor air pollution range from 150,000 to 350,000 people-equivalent to 2–3 fully loaded 200-passenger airliners crashing each day with no survivors. Millions more suffer from asthma attacks and other respiratory disorders and lose work time. Most of the deaths are related to inhalation of very small particulates from coal-burning power plants.

According to recent EPA studies, each year more than 125,000 Americans (96% of them in urban areas) get cancer from breathing soot-laden diesel fumes from buses and trucks. Other sources of these fumes include tractors, bulldozers and other construction equipment, and trains. A large diesel truck emits as much particulate matter as 150 cars, and particulate emissions from a diesel train engine equal those from 1,500 cars.

Premature deaths from air pollution in the United States, mostly from very small particles added to the atmosphere by coal-burning power plants. According to the American Lung Association, more that 2,000 scientific studies published since 1995 link particulate matter with adverse health effects.


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