Page 495 - Environment: The Science Behind the Stories

Geologic Radon Potential
Low Moderate / Variable High

Figure 17.33 One’s risk from radon depends largely on
underground geology. This map shows levels of risk across the
Figure 17.32 In the developing world, many people build United States. Testing your home for radon is the surest way to
fires inside their homes for cooking and heating, as seen determine whether this colorless, odorless gas could be a problem.
here in a Maasai home in Kenya. Indoor fires expose people to Data from U.S. Geological Survey, 1993. Generalized geological radon potential
severe pollution from particulate matter and carbon monoxide. of the United States, 1993.

to burn wood, charcoal, animal dung, or crop waste inside Radon gas is the second-leading cause of lung cancer
their homes for cooking and heating, with little or no ven- in the developed world, responsible for an estimated 21,000
tilation (Figure 17.32). In the air of such homes, the WHO deaths per year in the United States and for 15% of lung
has found that concentrations of particulate matter are com- cancer cases worldwide. Radon (p. 384) is a radioactive gas
monly 20 times above U.S. EPA standards. As a result, peo- resulting from the natural decay of uranium in soil, rock, or
ple inhale dangerous amounts of soot, carbon monoxide, and water. It seeps up from the ground and can infiltrate buildings.
other pollutants, which together increase risks of premature Colorless and odorless, radon’s presence can be impossible to
death by pneumonia, bronchitis, and lung cancer, as well predict without knowing an area’s underlying geology (Figure
as allergies, sinus infections, cataracts, asthma, emphysema, 17.33). The only way to determine whether radon is entering
and heart disease. International health researchers estimate a building is to sample air with a test kit. The EPA estimates
that indoor air pollution from burning fuelwood, dung, and that 6% of U.S. homes exceed its safety standard for radon.
coal kills 3.5 million people each year, comprising nearly Since the 1980s, millions of U.S. homes have been tested for
7% of all deaths. Many people are not aware of the health radon and close to a million have undergone radon mitiga-
risks, and of those who are, many are too poor to have viable tion. New homes are being built with radon-resistant features.
alternatives.

Many VOCs pollute indoor air
Tobacco smoke and radon are the primary
indoor pollutants in industrialized nations In our daily lives at home, we are exposed to many indoor air
pollutants (Figure 17.34). The most diverse are volatile organic
In industrialized nations, the primary indoor air health risks compounds (p. 477). These airborne carbon-containing com-
are cigarette smoke and radon, a naturally occurring radio- pounds are released by plastics, oils, perfumes, paints, clean-
active gas. Smoking cigarettes irritates the eyes, nose, and ing fluids, adhesives, and pesticides. VOCs evaporate from
throat; worsens asthma and other respiratory ailments; and furnishings, building materials, color film, carpets, laser
greatly increases the risk of lung cancer. Inhaling second- printers, fax machines, and sheets of paper. Some products,
hand smoke (smoke inhaled by a nonsmoker who is nearby such as chemically treated furniture, release large amounts of
or shares an enclosed airspace with a smoker) causes many VOCs when new and progressively less as they age. Other
of the same problems. This hardly seems surprising when one items, such as photocopying machines, emit VOCs each time
considers that tobacco smoke is a brew of over 4000 chemi- they are used.
cal compounds, some of which are known or suspected to be Although we are surrounded by products that emit VOCs,
toxic or carcinogenic. Smoking has become less popular in they are released in very small amounts. Studies have found
developed nations in recent years as a result of public edu- total levels of VOCs in buildings to be nearly always less
cation campaigns, and many public and private venues now than 1 part per 10 million. This is, however, a much greater
ban smoking. Still, smoking is estimated in the United States concentration than is found outdoors. Moreover, we experi-
alone to cause 160,000 lung cancer deaths per year, and sec- ence instances of especially high exposure. The “new car
494 ondhand smoke to cause 3000. smell” that fills the interiors of new automobiles comes from

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