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AIR POLLUTION

Air pollution occurs when the concentrations of (harmful, painful, injurious) substances become high enough to cause the atmospheric environment to become toxic. Air pollutants can be gaseous, liquid or (dependable, stable, solid) in form, and can come from natural as well as human sources. Examples of natural sources of air pollution include forest fires, volcanic pollution and dust. Human sources of air pollutants include (injections, diffusions, emissions) from industry, agriculture, forestry, transportation, power generation, and space heating.

Air pollution can threaten the health of human beings, trees, lakes, crops, and animals. Abundant amount of air pollution changes natural atmospheric processes, causing acid rains, ozone holes, and enhancing greenhouse effect.

INDUSTRIAL SMOG is considered the most serious type of air pollution. Smoke and oxides of that are (revealed, released, let out) by burning coal and oil containing minor amounts of sulfur is the cause. Industrial smog has been known to cause air pollution disasters. One of the worst occurred in London in December of 1952. Five days of stagnant air brought about high-pressure systems caused between 3,500 and 4,000 deaths. Industrial smogs in London were called (bean soups, pea soupers, smog soupers).

Another main cause of air pollution is (discharge, car gases, exhaust fumes) from vehicles that run on gasoline or diesel. Until a few years ago, lead was added to most gasolines to make car engines run better. Lead is a highly toxic metal and can cause nervous system damage and digestive problems. Now ecologically minded people try to use (lead-free, leadless, leaded) petrol to prevent air pollution.

Sulphur and (nytrogene, nitrogen, nitrogyne) oxides from power plants, industry, cars and other sources cause rain, snow and fog to become acidic. The most serious damage caused by (acidified, acidic, acid) RAIN today is acidification of water lakes and rivers. In some cases they become so acidic that they can no longer support fish and their food chains. Forest health can also be affected from this in areas where the soils are being acidified.

OZONE (destruction, depletion, reduction ) is another result of pollution. The ozone layer protects the earth from harmful ultraviolet radiation from the sun. Release of chlorofluorocarbons from aerosol sprays, polystyrene containers, refrigerator coolant and air conditioning units removes some of the ozone, causing "holes"; to open up in this layer and allowing the radiation to reach the earth.

The GREENHOUSE EFFECT is generally believed to come from the (build up, stand up, break out) of carbon dioxide gas in the atmosphere. The term refers to the role played by the layer of gases, including carbon dioxide, methane and nitrous oxide, which trap the heat from the sun in the earth’s atmosphere. We need the layer to keep in some of the heat but now the concentration of gases, especially CO2 is increasing and retaining more heat. As more heat is retained in the atmosphere, the average temperature of Earth's oceans and atmosphere rises, which causes (air contamination, global warming, climate change). An increase in global temperature will cause sea levels to rise and will change the amount and pattern of precipitation, probably including expansion of subtropical deserts. Warming is expected to be strongest in the Arctic and would be associated with continuing melting of sea ice. Other likely effects of the warming include more frequent occurrence of extreme weather events including heatwaves, droughts and heavy rainfall events, species extinctions due to shifting temperature regimes. Warming and related changes will vary from region to region around the globe, though the nature of these regional changes is uncertain.

Finally, air pollution can also occur indoors. Common indoor air pollutant is carbon monoxide from faulty gas heaters and cookers, and volatile organic compounds (VOCs) from synthetic furnishings and paints. Adequate ventilation is a key to controlling exposure to indoor air pollution. Home and work environments should be monitored for adequate airflow and proper exhaust systems installed.

The problem of air pollution is worldwide and transcends national boundaries. Though air pollution is still a serious problem, in many countries in the world, steps are being taken to stop the damage to our environment from air pollution. Many electric power plants, factories, and facilities that burn wastes are equipped with devices called scrubbers. Scrubbers remove sulphur dioxide and other pollutants before the wastes are released into the air. Also, today's cars are designed to create less pollution. Many are equipped with anti-pollution devices called catalytic converters, which reduce the amount of pollution from automobile engines.

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Дата добавления: 2015-10-30