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|Referát vhodný pre:||Stredná odborná škola||Počet A4:||2.2|
|Priemerná známka:||2.96||Rýchle čítanie:||3m 40s|
|Pomalé čítanie:||5m 30s|
Where is the problem? Acid pollution ranges everywhere from the U.S.(the world's biggest producer of sulfur dioxide) to the Arctic(the world smallest producer of sulfur dioxide). Because of prevailing winds acidic water droplets can be carried long distance, returning to earth as acid rain, snow or fog. Canada, for example, produces about half of it's own acid rain and imports the rest from the U.S. There are 4 ways to reduce gases(which contain sulphur dioxide and nitrogen oxides) from power plants. The first and probably best way is energy conservation. This means using less energy. Less energy means less coal burned in power plants. Burning less coal means less acid in the air. Burning low-sulfur coal is the second step. There is a difference between high-sulfur coal and low-sulfur coal. High-sulfur coal will give off more sulfur in the air when it is burned. Burning low-sulfur coal will give off less sulfur which means less acid will enter the air. However, high- sulfur costs two thirds the price of low-sulfur coal. Then there are smokestack scrubbers. Scrubbers capture sulfur from smoke before it enters the air. The captured sulfur is mixed with other things, such as lime. This creates a semiliquid which looks like wet cement. This also becomes a problem. The captured sulfur has nowhere to go. One power plant can capture an amount of 400 tons of sulfur mixture a day. Then there's the last way-search for alternate energy sources. One alternate source is nuclear power, but some believe this source may create problems even worse than acid rain. Other sources include solar power (power from the sun) and wind power. These two sources have hardly ever been tried. .