Environmental Engineering Reference
In-Depth Information
chromosomal abnormalities, and DNA damage from breathing diesel
fumes all day. According to the American Lung Association, Los Angeles
has the worst air in the United States. Eight of the ten cities with the
most polluted air are in California, with Houston at number seven and
Charlotte, North Carolina at number ten.
Humans probably fi rst experienced harm from air pollution when
they built fi res in poorly ventilated caves. Since that time, we have
managed to pollute the air everywhere we have settled and even places
we have yet to colonize, such as Antarctica and uninhabited parts of
northern Canada. The pollution precedes our arrival; it is waiting
patiently until we arrive. Probably the nation with the worst air pollution
problem is China. People in the major cities walk around with surgical
masks on their faces to fi lter out the particulate material in the air they
must breathe. In a World Bank list of the world's most polluted places,
China has twelve of the top eighteen cities, India has four, and Egypt
(Cairo) and Indonesia (Jakarta) have one each.
2
Acid rain produced from the sulfurous fumes emitted from coal-fi red
power plants and factories kills fi sh in northeastern lakes. Plants are
similarly affected. Pollutant haze from soot and other aerosols reduces
the penetration of sunlight and decreases photosynthesis. Commercial
fruit size and weight decrease. Plant death in the fi eld has increased
because the weakened vegetation is more vulnerable to injury from
diseases and pests. In summary, air pollution is harming our health,
decreasing our longevity, and attacking our crops.
What's in the Air We Breathe?
Determinations of the amounts of the major pollutants in the air we
breathe have been made for many decades and are reported annually by
the American Lung Association and Environmental Protection Agency.
3
All of the pollutants are bad for human health, and the proportions of
each vary yearly. Establishing the effect on human health of each is dif-
fi cult because all are ingested simultaneously and their effects overlap.
And there are no volunteers to conduct controlled experiments. But it is
clear that progress on removing all of them is essential.
Soot
Soot is arguably the most damaging type of particle to humans of the air
pollutants we eject from our fossil-fueled inventions. In government pub-
lications, soot is referred to as particulate matter (PM) and is classifi ed by
