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How to Avoid Acid Rain


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        <p>Acid rain is a popular phrase used to describe rain, snow,
fog, or other precipitation that is full of acids that collect in the
atmosphere due to the burning of fuels such as coal, petroleum, and
gasoline. Acid rain was first recognized in Europe in the late 1800s but
did not come to widespread public attention until about 1970, when its
harmful effects on the environment were publicized. Research has shown
that in many parts of the world, lakes, streams, and soils have become
increasingly acidic, prompting a corresponding decline in fish
populations. Acid rain occurs when polluted gases become trapped in
clouds that drift for hundreds, even thousands, of miles and are finally
released as acidic precipitation. Trees, lakes, animals, and even
buildings are vulnerable to the slow, corrosive effects of acid
rain.</p><br> <br> <p>Acidification, the process of making acid, is not
just caused by deposits of acidic rain but also by chemicals in snow and
fog and by gases and particulates when precipitation is not occurring.
The major human-made causes of acid deposition are (1) emissions of
sulfur dioxide from power plants that burn coal and oil and (2) emissions
of nitrogen oxides from automobiles. These emissions are transformed into
sulfuric acid and nitric acid in the atmosphere, where they accumulate in
cloud droplets and fall to Earth in rain and snow, wet deposition. Other
sources of acid deposition are gases like sulfur dioxide and nitrogen
oxides, as well as very small particulates. These gases and particulates
are usually deposited when it is not raining or snowing which is called
dry deposition.</p><br> <br> <p>Â While large areas of Europe and North
America are exposed to acidifying depositions, only certain types of
ecosystems are affected by these depositions. The most vulnerable
ecosystems usually have a thin cover of soil, containing little calcium
and sitting upon solid rock made up of hard minerals such as granite or
quartz. Many freshwater lakes, streams, and rivers have become acidic,
resulting in the decline or local destruction of some plant and animal
populations. It is not yet certain that land-based ecosystems have been
affected by acidic deposition. After acid rain was discovered in Europe,
scientists began measuring the acidity of rain in North America.
Initially, they found that the problem was concentrated in the
northeastern states of New York and Pennsylvania because the type of coal
burned there was more sulfur containing. </p><br> <br> <p>Acid rain is
measured through pH tests that determine the concentration of hydrogen
ions in a liter of fluid. The pH scale is used to measure acidity or
alkalinity. It runs from 0 to 14. Water has a neutral pH of 7. The
greater the concentration of hydrogen ions and the lower the pH number,
the more acidic a substance is and the lower the concentration of
hydrogen ions and the higher the pH number, the more alkaline or basic a
substance is. So a pH greater than 7 indicates an alkaline substance
while a pH less than 7 indicates an acidic substance. It is important to
note that a change of only one unit in pH equals a tenfold change in the
concentration of hydrogen ions. For example, a solution of pH 3 is 10
times more acidic than a solution of pH 4. Normal rain and snow measure
about pH 5.60. In environmental science, the definition of acid
precipitation refers to a pH less than 5.65.</p><br> <br> <p>Measured
values of acid rain vary according to geographical area. When pH levels
are drastically upset in soil and water, entire lakes and forests are
endangered. Evergreen trees in high elevations are especially vulnerable.
Although the acid rain itself does not kill the trees, it makes them more
susceptible to disease. Also, high acid levels in soil cause leaching of
other valuable minerals such as calcium, magnesium, and potassium. Small
marine organisms cannot survive in acidic lakes and rivers, and their
depletion affects the larger fish who usually feed on them, and,
ultimately, the entire marine-life food chain. Snow from acid rain is
also damaging; snowmelt has been known to cause massive, instant death
for many kinds of fish. Some lakes in Scandinavia and New York's
Adirondack Mountains are completely devoid of fish life. Acid rain also
eats away at buildings and metal structures. From the Acropolis in Greece
to Renaissance buildings in Italy, ancient structures are showing signs
of corrosion from acid rain. In some industrialized parts of Poland,
trains cannot exceed 40 miles (65 kilometers) per hour because the iron
railway tracks have been weakened from acidic air pollution. Usually,
waters affected by acid rain are treated by adding limestone or lime, an
alkaline substance (base) that reduces acidity. Fishery biologists
especially are interested in liming acidic lakes to make them more
habitable for sport fish. In some parts of Scandinavia, for instance,
liming is used extensively to make the biological damage of acidification
less severe.</p><br> <br> <p>While neutralizing ecosystems that have
become acidic, treats the symptoms but not the sources of acidification.
Although exact sources of acid rain are difficult to pinpoint and the
actual amount of damage caused by acid deposition is uncertain, it is
agreed that acid rain levels need to be reduced. Scientific evidence
supports the notion that what goes up must come down, and because of
public awareness and concerns about acid rain in many countries,
politicians have begun to act decisively in controlling or eliminating
human causes of such pollution. Emissions of sulfur dioxide and nitrogen
oxides are being reduced, especially in Western Europe and North America.
For example, in 1992 the governments of the United States and Canada
signed an air-quality agreement aimed at reducing acidifying depositions
in both countries. While countries in Western Europe and North American
have actively carried out actions to reduce emissions of gases leading to
acid deposition for a number of years, countries in other parts of the
world have only recently addressed the issue. In Eastern Europe, Russia,
China, India, Southeast Asia, Mexico, and various developing nations,
acid rain and other pollution problems are finally gaining notice. For
example, in 1999, scientists identified a haze of air pollution that
hovers over the Indian Ocean near Asia during the winter. The 3.8
million-square-mile haze (about the size of the combined area of all
fifty American states) is made up of small by-products from the burning
of fossil fuels. Such a cloud has the potential to cool Earth, harming
both marine and terrestrial life.</p><br>         <!--INFOLINKS_OFF-->

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