The Human's Impact on Acid Rain
Acid rain is any precipitation that is acidic in nature. Rain is
already slightly acidic in nature because as it falls, it dissolves
some of the carbon dioxide in the atmosphere and falls as very dilute
carbonic acid. This is not significantly harmful to the environment
Even though the concentration of Nitrogen oxides and sulphur oxides
(which are the main causes of acid rain), are much less than the
concentration of carbon dioxide in the atmosphere, the former gases
are much more soluble and therefore have a much greater effect on the
acidity of the precipitation. Liquid acid rain is dissolved in the
rain and ...view middle of the document...
For example, U.S. nitrogen
oxides emissions for 1998 amounted to 23.7 million tones.
Because of the increase in population, there is more demand for
energy, especially in the form of electricity (for which the main
source is coal fired power stations. Also, the demand for cars has
increased, causing greater air pollution.
Causes of Acid Rain
The artificial causes of acid rain have already been mentioned above.
Sulpur dioxide is the result of base-metal smelting (In iron and steel
production, the smelting of metal sulfate ore, produces pure metal.
This causes the release of sulfur dioxide. Metals such as zinc,
nickel, and copper are usually produced by this process), of the
combustion of coal to provide electricity (coal is a fossil fuel,
which contains 2-3% of sulphur, which is released upon burning), of
and also fuel combustion in vehicles. (Overall, 69.4 percent of sulfur
dioxide is produced by industrial combustion and 3.7 percent is caused
by transportation.) It can also be the result of natural disasters, or
natural process like volcanic eruptions or organic decay. (Ten percent
of all sulfur dioxide emission comes from volcanoes, sea spray,
plankton, and rotting vegetation).
Sulphur dioxide first undergoes an oxidation reaction, and the can be
dissolved by the rain to form acidic sulphuric acid.
Nitrogen oxides are a result of combustion at extreme high
temperatures (like in car exhausts) and also chemical industries (for
example, in fertilizer production). Natural process includes bacterial
nitrogen-fixing action in soil, forest fires, volcanic action, and
lightning, which make up five percent of nitrogen oxide emission.
Nitrogen oxides first rise into the atmosphere and are oxidized in
clouds to form nitric or nitrous acid. Then in the atmosphere it
reacts with water to form nitric or nitrous acid.
Effects of acid rain
Acid rain affects many areas of our environment.
In aquatic systems, acid rain lowers the pH of the water, more and
more organisms die. The decreased pH causes mucus to build up between
the fish gills, and this makes them unable to get oxygen. So they die
from suffocation. Also, acidified waters contain high concentrations
of poisonous metals like mercury, aluminuim and cadmium. These metals
are usually in the bedrock surrounding the water locked in clay
particles, minerals and rocks, but the increased acidity causes these
metals to become soluble and pollute the water. As the water pH
approaches 6.0, crustaceans, insects, and some plankton species begin
to die. And at below pH 5, the water is almost entirely devoid of
fish. The decrease of fish will affect the ecosystem because of its
complicated and interlinked nature. For example, the birds will have
less to eat, and cause a decrease in the numbers of fish etc. The