210 CHAPTER 8 Air and Air Pollution
Priti Bhatt/Flickr / Getty Imagestotal annual cost to the economy may be as much as $50
billion. Fortunately, most building problems are relatively
inexpensive to alleviate.
Indoor air pollution is a particularly serious health
hazard in developing countries, where many people
burn fuels such as firewood or animal dung indoors to
cook and heat water (Figure 8.17). Smoke from in-
door cooking contains carbon monoxide, particulates,
hydrocarbons, and other hazardous air pollutants such
as formaldehyde and benzene. Women and children are
harmed the most by indoor cooking, which can cause
acute lower respiratory infections, pneumonia, eye in-
fections, and lung cancer. The World Health Organi-
zation estimates that smoke from indoor cooking kills
1.6 million people each year.
Radon
Radon is a colorless, odorless, tasteless radioactive
gas produced naturally as a result of the radioactive
decay of uranium in Earth’s crust. In the United States,
radon has become an increasingly important indoor air
contaminant, especially as laws and changes in habits have
reduced secondhand cigarette smoke exposure. Radon
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Cooking indoors with open fires or traditional cooking stoves
results in dangerous levels of indoor air pollution.
Radon
escapes
outdoorsFloor cracksWall and
foundation
cracks
Drain
pipesHow radon infiltrates a house
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Cracks in basement walls or floors, openings around pipes, and
pores in concrete blocks provide some of the entries for radon.seeps through the ground and enters buildings, where it
sometimes accumulates to dangerous levels (Figure 8.18).
Radon emitted into the atmosphere gets diluted and dis-
persed and is of little consequence outdoors.
Radiation associated with radon decay does not pen-
etrate deeply into body tissue. Consequently, only in-
gested or inhaled radon harms the body. The National
Research Council of the National Academy of Sciences
estimates that residential exposure to radon causes 12
percent of all lung cancers—between 15,000 and 22,000
lung cancers annually. Cigarette smoking exacerbates
the risk from radon exposure; about 90 percent of radon-
related cancers occur among current or former smokers.
According to the EPA, about 6 percent of U.S. homes
have high enough levels of radon to warrant corrective ac-
tion—a radon level above 4 picocuries per liter of air. The
curie is a standard measure of radiation dose; a picocurie
is one billionth of a curie. As a standard of reference, out-
door radon concentrations range from 0.1 to 0.15 picocu-
ries per liter of air worldwide. The highest radon levels in
the United States are found in homes across southeastern
Pennsylvania into northern New Jersey and New York.