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Studijní materiály
Zjednodušená ukázka:
Stáhnout celý tento materiálEnviromental issues
Civilization has brought people many advantages but its products also pollute and damage the environment in witch we live. Pollution affects air, water, land, forests, people, animals and plants.
Air pollution is the biggest problem in large cities and in areas with concentrated industrial production. Emissions range from smoke, dust, and smells to car and lorry exhausts. Smoke contains sulphur dioxide (SO2), nitrogen oxide (NO) and carbon dioxide witch are produced by coal-fired power stations and factories. Substances such as SO2 and NO can cause major changes in the environment which can lead to climate changes.
These substances mix with water vapour in the atmosphere and from sulphuric acid and nitric acid. Sunlight turns these acids into poisonous oxidants which fall in the form of acid rain onto trees and kill them.
Trees are vitally important for our life because they are the lungs of our planet. They absorb carbon dioxide from the air and give our oxygen in return. In some parts of the world, such as Asia and South America, trees are not threatened by pollution, but by people. The great rain forests are being destroyed for firewood and building materials. (The Amazon rain forest covers an area as large as the whole of Europe and contains one third of the world’s trees, provides 50 per cent of the world’s annual production of oxygen). If we lose tropical forests, it will become more difficult, perhaps even impossible, to breath. With more carbon dioxide in the air, the temperature will rise; the ice-caps at the North and South Poles will melt, and the sea level will rise which will result in the flooding of many coastal cities.
Greenhouse effect can also cause climate change. Without this effect there could be no life on earth because the earth is warmed up naturally by the atmosphere which traps solar radiation. But manmade atmospheric emissions, such as carbon dioxide, nitrogen oxides, CFCs from aerosol and refrigerators and water vapour prevent the heat from escaping. The result is a rise in the Earth’s temperature, the melting of arctic ice and the flooding of areas situated near sea level.
Ozone is another air pollutant. It is produced by the reaction of sunlight on car exhaust fumes and is a major air pollutant in hot summers. On the ground level ozone can cause asthma attacks, corrosion of certain materials and stunted growth of plants which lowers the yields of some crops. On the other hand, ozone forms a layer in the upper atmosphere which protect life on Earth from ultraviolet rays, which is a cause of skin cancer. A continent-sized hole has formed over Antarctica as a result of damage of the ozone layer, caused in part by CFCs.
How can the problem of air pollution be solved? People should try to use alternative source of energy, such as solar, water and wind energies. There are more ways to reduce air pollution caused by road traffic. First it is possible to switch freight from road to railways and to support public transport. Another way is to encourage tree planting, because trees absor
Vloženo: 4.09.2010
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