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Реферат: Air Pollution /enlish/

Alexander V. Myskin, gr. 301

Air Pollution

Air, is the most essential element for all living organisms and yet,
most humans play a big role on polluting this essential resource. Air
pollution may not be as dangerous in its direct outcome as nuclear or
water pollution can be, but in the long term it will have an tremendous
effect on the environment and health of its organisms living in. Asthma,
cancer, acid rain, and the disability to photosynthesize are only a few
causes of air pollution.The atmospheric pollutants with the greatest
effect onto the environment are the carbon monoxide, carbon dioxide,
hydrocarbons, sulfur dioxide, nitrogen oxides, dust particles,
radioactive isotopes, and chlorofluorocarbons. The major sources that
enable carbon monoxide to enter the atmosphere are the exhausts of cars,
the burning of fossil fuels, and the oxidation of natural methane.
Carbon dioxide is caused by the consumption of fossil fuels only and it
causes the possible greenhouse effect which has global warming as an
outcome. Hydrocarbons are caused by the combustion of oil and petrol and
it effects the environment with carcinogen. Carcinogen is a chemical
agent that causes cancer. Sulphur dioxide is certainly one of the major
atmospheric pollutants considered that it causes stinging eyes, lung
damage, asthma, and acid rain. It is the result of coal-fired power
stations. Nitrogen oxides that is produced by the exhaust of cars,
causes pneumonia and asphyxia. The outcome of the well known dust
particles is often underestimated. It is caused by industrial chimneys,
car exhaust, and volcanic eruptions and it effects the environment by
toxic effects and damage of the lungs. Radioactive isotopes which are
caused by small quantities from nuclear waste and nuclear accidents
have an carcinogenic effect on the environment as well. The outcome of
chlorfluorocarbons, which had been first discovered in the 80s is that
it destroys the ozone layer. Many of those major atmospheric pollutants
combined produce the dangerous and well known smoke and gas emission
called smog.

Smog or dust dome is most often formed when a layer of cool air is
trapped beneath a layer of still warmer air. The mixture of benzopyrene
( a cancer causing substance that is produced by the evaporation of
petrol), the waste of hydrocarbons, combined with nitrogen dioxide,
oxygen, and sunlight produce the photochemical smog which can be
recognized as the yellow cloud over every big city in the world. Besides
that optical effect it causes an increase of ozone in the lower
atmosphere and the health conditions of the particular organism living
in such an area. For example, it is estimated that “Washington DC
receives 10% less sunlight than at the begging of the century due to the
shielding of atmospheric pollution.” The ozone enters the leaves of
plants turning them brown and makes it difficult for plant to
photosynthesize. In addition to that, it causes skin cancer on humans.
Most seriously though, it increases the acidity of the rain which is
mainly caused by the rise of sulphur dioxide and nitrogen oxides that
get caught up by clouds. All ready unpolluted rain is slightly acid due
to dissolved carbon dioxide, but polluted rain may be very acidic. The
effect of acid rain on terrestrial and aquatic ecosystems can be very
different. “In Scandinavia, which receives a high proportion of its air
pollution from Britain, once productive lakes are now completely devoid
of fish.” In addition to its direct effect on water, acid rain allows
metal ions such as aluminum, which is highly toxic to fish, to be
leached from the soil . Acid rain reduces the growth of trees and
disables plants to photosynthesize which destroys them in the long term.
It also reduces the activity of nitrogen-fixing bacteria. In the event
of a nuclear accident or war, the main risks do lay only partly in the
pollution of air and air as a carrier of the polluted particles. The
main risks arise from inhalation of contaminant particles, fallout of
radioactive isotopes on soil with subsequent incorporation into food,
and contamination of water supplies. The outcome of all those pollutant
factors are enormous. The smoke from car engines which contains lead,
that causes brain damage in children, stinging eyes, damage of the lung,
the death rate of 40.000 asthma patients every year, and the destruction
of whole forests includes only a few examples of the effects of air
pollution. There are many ways to control and reduce air pollution and
it is not the lack of technology but the unwillingness of the humans to
change their attitudes and life styles.

It exists a wide range of technology for effective air pollution.
Emissions of dust can and should be controlled by filters which remove
solid particles before gases are discharged. Low sulphure fuels could be
used in order to reduce the sulphure emission from coal-fired power
stations. For all other forms of waste that get released during
production into the air, technology provides a wide range of filters
which are able to remove 80-95% of sulphur dioxide gas. The control of
emission from the most common pollutant, the car, improvements can be
made. The use of lead free patrol and catalytic converters would reduce
toxic emissions to a fraction of their present level and prevent damage
to the environment. Of course are the big companies the one which
produce most waste and cause most pollution, but in order to change and
reduce the air pollution, everyone, even the smallest household, needs
to change its attitudes and be more responsible with the limited sources
the nature is providing. If humans would be less greedy for money and
willing to ensure a safe and clean environment for the children of
tomorrow, vast improvements could be made that would be beneficial for
the whole world.

© 2011 Рефераты