AIR POLLUTION
Factories
and transport depend on huge amounts of fuel – billions of tons of coal and oil
are consumed worldwide each year. When these fuels burn, they release smoke and
other, less visible byproducts into the atmosphere. While wind and rain
occasionally wash away smoke from power plants and cars, the overall impact of
air pollution is a serious threat to people and the environment.
In
many places, smoke from factories and cars naturally combines with fog to form
smog. For centuries, London, England has been threatened by smog, which has
long been considered a possible cause of death, particularly among the elderly
and those suffering from serious respiratory illnesses. Air pollution in London
was originally caused by the massive use of thermal fuel.
Widespread
awareness of air pollution began around 1950. It was originally associated with
the Los Angeles area. Much of the Los Angeles Basin is surrounded by high
mountains. As the wind descends from these mountains, it heats up until it
accumulates as a hot layer that rises above the cool air from the Pacific
Ocean. This results in a temperature reversal and heavy cold air confined to
the surface. Pollution also gets stuck at surface level. Because of air
circulation patterns in the Los Angeles Basin, contaminated air moves from one
part of the basin to another.
Scientists
believe that all cities with more than 50,000 inhabitants have some degree of
air pollution. The burning of waste in open dumps, which still occurs in some
countries, causes air pollution. Other sources include the release of sulfur
dioxide and other harmful gases from power plants that burn more sulfurous coal
or oil. Industrial boilers in factories also send large amounts of smoke into
the air. The steel and plastic manufacturing process produces large amounts of
smoke that contains metal dust or complex and sometimes microscopic particles
of deadly chemicals.
The
single main cause of air pollution is the inboard right engine of cars.
Gasoline in a vehicle engine never burns completely, just like coal in a steel
mill never burns completely. Once incomplete, the products of the
dahan—particulate matter (mascara, ash, and other solids), unburned
hydrocarbons, carbon monoxide, sulfur dioxide, various nitrogen oxides, ozone,
and lead—go through a series of chemical reactions as they are released into
the air. In the presence of sunlight. The result is a characteristic of dense
smog. Smog can be brown when it's high in nitrogen dioxide, or blue-brown when
it's high in ozone. In both cases, long-term exposure will damage lung fats.
Air
pollution has a huge impact on the health and well-being of people around the
world. Air pollution contributes to the increasing incidence of asthma,
bronchitis and emphysema, a serious and debilitating disease of the air sacs in
the lungs. Additionally, current studies suggest that air pollution may be
linked to heart disease.
In
the mid-1970s, people became aware of a trend called acid rain. Burning fossil
fuels such as coal, gasoline, and heating oil releases sulfur, carbon, and
nitrogen oxides into the air. These oxides, combined with water particles in
the atmosphere, reach Earth as acid rain, snow, hail, sleet or fog. A certain
scale, called the ph scale, measures whether a liquid (including rain and ice)
is acidic or basic (alkaline). The Ph scale is used to describe the
concentration of electrically charged hydrogen atoms in an aqueous solution.
The scale ranks the substance from 0 to 14. PH 7, as in ast water, means that
the solution is neutral. Above PH7 means the solution is critical. Below 7
means the solution is acidic. Normal rainwater has a pH of about 5.6.
Although
the National Center for Atmospheric Research has recorded thunderstorms in the
northeastern United States with a pH of 2.1, which is the acidity of lemon
juice or vinegar, the average of the most acidic precipitation in the United
States in the early 2000s was a pH of 4.3. In Canada, Scandinavia and the
northeastern United States, acid rain is blamed for the death of thousands of
lakes and rivers. These lakes have absorbed so much acidity that they can no
longer support tahalab, plankton and other aquatic life. Provide food and
nutrients to the fish. Acid rain also damages buildings and monuments,
including centuries-old monuments such as the Roman Colosseum. Scientists fear
that the death of thousands of trees in the forests of Europe, Canada and the
United States may be the result of acid rain. While many industrialized
countries have tried to make changes to help reduce sulfur dioxide and other
air pollution, less developed countries do not always have the resources to
implement such high-tech solutions.
Another
troubling form of air pollution comes from a type of man-made chemicals called
chlorofluorocarbons, also known as CFCs. These chemicals are used for many
industrial purposes, from the solvents used to clean computer chips to the
refrigerated gases found in air conditioners and refrigerators. CFCs combine
with other molecules in the Earth's upper atmosphere, and then when they
combine with ozone molecules, they alter and destroy the protective ozone layer
below. As a result, there was a drastic decrease in the ozone content of the
planet. At ground level, ozone is a threat to our lungs, but in the upper
atmosphere, ozone acts as a shield against the sun's ultraviolet rays. If the
ozone shield becomes too thin or disappears, exposure to ultraviolet rays can
cause crop failures and outbreaks of epidemics, skin cancer and other
disasters. By the end of 1987, more than 20 countries had signed the Montreal
Protocol to reduce production of CFCs and were working to phase them out; by
2007, more than 190 countries had joined the agreement. The production of CFCs
in developed countries ended in 1996, and now the agreement has been modified
to reduce and eliminate the use of hydro chloro fluoro carbons, which replaced
CFCs.
Air
pollution has become the target of the most complex and far-reaching
legislation ever introduced in the United States. In 1970, Congress passed
legislation aimed at limiting sources of air pollution and setting standards
for air quality. A few years later, Congress passed laws designed to phase out
the use of lead as an additive in gasoline. In 1990, the Clean Air Act was
amended to limit automobile emissions and promote alternative fuels. Further
measures to reduce acid rain and greenhouse gas emissions are constantly being
debated in North America, across Europe and the rest of the world.
Although
the release of toxic chemicals into the air is illegal in most countries,
accidents can happen, often with tragic consequences. In 1984, a pesticide
factory in Bhopal, India released a toxic gas into the air, killing more than
2,000 people within hours.
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