Air pollution can include many things. In
general, the term "air pollution" usually
to anything in the air that came unnaturally and
which is harmful to the earth or to our health.
For example, if somebody starts a fire that burns
down a building, a lot of black smoke goes up into
the air. The smoke from the building causes bad
air pollution, and if you get too close it will
make your eyes water and you will start to cough.
Sometimes when you are driving through a
city with your parents you might see a big factory
with long smokestacks that have smoke coming out
of them. When you're driving on the freeway you
might see a big truck with smoke coming out of
pipes from its roof. These are also examples of
things producing air pollution in the form of
smoke. Your car also produces this kind of
pollution from its tailpipe! Sometimes you can
see it coming out and sometimes you only smell it.
These kinds of pollution create smog in the air,
which is the brown hazy stuff you see sometimes
hanging low in the sky.
There are many
types of air pollution which we can't see or even
smell. One type of pollution that is a big
concern right now is carbon dioxide. When
something it produces a lot of carbon dioxide in
addition to smoke. We can't see or smell the
carbon dioxide, but it goes up into the atmosphere
and a lot of people are worried about problems
that it can cause there.
(including humans) breathe, we take in oxygen and
expel carbon dioxide into the air. This means
that animals are indeed a source of one kind of
air pollution. Animals also produce methane,
which is another air pollutant. Plants are
generally good for the air, because they remove
harmful compounds such as carbon dioxide, but if
the plants get burned such as in a forest fire
then they will produce a lot of smoke. Also many
plants produce pollen which may make people
sneeze. However, people usually aren't very
worried about these kinds of pollutants, because
they all come from natural processes. Although
animals produce carbon dioxide, it is a very small
amount compared to what is being put into the
atmosphere through burning gas, coal, and oil.
When a plant burns, the compounds it
releases into the air aren't very dangerous
compared to the compounds released from industrial
processes (although in the case of a forest fire,
where there's a lot of smoke, the air can become
very polluted for a short time).
although these types of things can contribute to
air pollution, they aren't usually the big
concern. Besides, people can't really control
these natural sources very well, and so they would
rather focus on the things that we can control!