206 CHAPTER 8 Air and Air Pollution
Clean gas
out
Electrode
(negative charge)
Dust falls off
wall into
collector
Dirty gas
(smoke) in
Precipitator wall
(positive charge)
Kodda/ Shutterstock
Adapted from Joesten, M.D. and Wood, J.L.
World of Chemistry,
2e.
Philadelphia: Saunders College Publishing (1996).
Image Source / Getty Images
a. In an electrostatic precipitator, the electrode imparts a negative charge to
particulates in the dirty gas. These particles are attracted to the positively charged
precipitator wall and then fall off into the collector.
b. Industrial stacks without emission control devices
can release substantial amounts of particulate
matter and other pollutants.
c. Effective emission control devices can reduce
particulate matter and other pollutants.
fuel-efficient automobiles produce fewer polluting emis-
sions, for example.
The primary objections to using these technologies
is cost. Adding scrubbers or electrostatic precipitators to
existing plants increases the cost of doing business. Like-
wise, adding catalytic converters to automobiles increases
their price. Several methods exist for removing sulfur ox-
ides from flue (chimney) gases, but it is often less expen-
sive simply to switch to a low-sulfur fuel such as natural gas
or even to a non–fossil fuel energy source, such as solar
energy. Sulfur can also be removed from fuels before they
are burned.
Reduction of combustion temperatures in automo-
biles lessens the formation of nitrogen oxides. Use of
mass transit reduces automobile use, thereby decreasing
- Summarize the effects of the Clean Air Act on
U.S. air pollution. - Contrast air pollution in highly developed
countries and in developing countries.
T
echnology exists to control all the forms of
air pollution discussed in this chapter.
Smokestacks fitted with electrostatic precipi-
tators, fabric filters, scrubbers, and other
technologies remove particulate matter from the air
(Figure 8.14). Careful land-excavating activities, such as
sprinkling water on dry soil being moved during road
construction, reduces the creation of particulate matter.
Many of the measures that increase energy efficiency and
conservation also reduce air pollution. Smaller, more
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Controlling Air Pollutants
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