12.1 what causes air pollution
ZEV programs have also been adopted by
Maine, Massachusetts, New York, and Vermont.
A scrubber is
a machine that moves gases through a spray of water that dissolves many pollutants.
secondary pollutant is
a pollutant that forms in the atmosphere by chemical reactions with primary air pollutants, natural components in the air, or both.
primary pollutant is
a pollutant that is put directly into the atmosphere by human or natural activity.
SOURCES OF PRIMARY AIR POLLUTANTS
Household products, power plants, and motor vehicles are sources of primary pollutants such as carbon monoxide, nitrogen oxide, sulfur dioxide, and chemicals called volatile organic compounds (VOCs).
pollutants enter the air
Whenever something burns
The circulation of air in the atmosphere usually keeps
air pollution from reaching dangerous levels.
In 1273, King Edward I ordered that
burning a particularly dirty kind of coal called sea-coal was illegal.
VOCs are
chemical compounds that form toxic fumes.
Smog results from
chemical reactions that involve sunlight, air, automobile exhaust, and ozone.
When people use some of the products that contain VOCs
even more VOCS are added to the air.
Many industries and power plants that generate our electricity must burn
fuel, usually fossil fuel, to get the energy they need.
The EPA required
he gradual elimination of lead in gasoline, decreasing lead pollution by more than 90 percent in the United States.
Most air pollution is the result of
human activities but some pollutants are natural, including dust, pollen, spores, and sulfur dioxide from volcanic eruptions.
The Clean Air Act requires
many industries to use scrubbers or other pollution-control devices.
The Clean Air Act, passed in 1970 and strengthened in 1990, gives the Environmental Protection Agency (EPA) the authority to
regulate vehicle emissions in the United States.
Substances that pollute the air can be in the form of
solids, liquids, or gases.
Scrubbers remove
some of the more harmful substances that would otherwise pollute the air. Ammonia is an example
Burning fossil fuels releases huge quantities of
sulfur dioxide and nitrogen oxide into the air.
Power plants that produce electricity emit
t least two-thirds of all sulfur dioxide and more than one-third of all nitrogen oxides that pollute the air.
Zero-emission vehicles are vehicles that have no
tailpipe emissions, no emissions from gasoline, and no emission-control systems that deteriorate over time.
Sometimes, however, pollution is trapped near Earth's surface by a
temperature inversion.
A temperature inversion is
the atmospheric condition in which warm air traps cooler air near Earth's surface.
Air pollution is
the contamination of the atmosphere by wastes from sources such as industrial burning and automobile exhausts.
Ground level ozone forms when
the emission from cars react with the UV rays of the sun and then mix with the oxygen in the atmosphere.
In 1990, the California Air Resources Board established
the zero-emission vehicle (ZEV) program.
Dry cleaning, oil refineries, chemical manufacturing plants, furniture refinishers, and automobile repair shops all contribute
to the VOCs in the air.
Smog is
urban air pollution composed of a mixture of smoke and fog produced from industrial pollutants and burning fuels.
Pollutants released by
vehicles and industries are the main causes of smog.
Most air pollution in urban areas comes from
vehicles and industry.
