about human interactions with the environment.
Air is a mixture of nitrogen, oxygen, carbon dioxide, water
vapor, and other gases.Cycles of nitrogen, oxygen, and carbon
dioxide guarantee that Earth's air supply will never run out,
but they don't guarantee that it will be clean. Pollutants
such as ash, gases, and chlorine, can be harmful to the health
of humans and other living things and can even change the
climate of the whole planet.
Photochemical smog is a thick, brownish haze fromed when certain
gases in the air react with sunlight. The major sources of
photochemical smog are the gases emitted by automobiles and
trucks. Burning gasoline in a car engine releases hydrocarbons
and nitrogen oxides into the air.The gases react in the sunlight
to form ozone, the major chemical found in smog.
Another type of air pollution is caused by powerplants and
factories that burn coal and oil. The nitrogen and sulfur
oxides react with the wator vapor in air and create nitric
and sulfuric acid. Thus the acids return to Earth's surface
dissolved in precipitation. When acid rain falls into lakes
or ponds, it has hazardous effects upon fish and their eggs.
When the acid rain falls upon the ground it can affect the
nutrients in the soil and harm plantlife.
Some people believe they can avoid air pollution if they remain
indoors. This is a false assumption. Minor pollutants such
as pet hair, dust, and air freshners bother only people allergic
to them. But there still exists more widespread pollutants.Asbestos,
a building material, can cause lung disease. Products such
as oil-based paints, glues,and cleaning supplies may release
toxic fumes. Smoking is also a pollutant, that when is inhaled,can
damage the lungs and heart.
Being sunburned is an effect of the suns ultraviolet radiation.
The ozone layer is a layer of the upper atmosphere about 30
kilometers above Earth's surface. Even the small amount of
ozone, only a few parts per minute in the ozone layer protects
people from the effects of too much ultrviolet radiation.
The effects of too mujch radiation can result in sunburn,
eye diseases, and skin cancer.