课题—酸雨（Topic acid rain）.docVIP

课题—酸雨（Topic acid rain） I. brief introduction of acid rain At present, the human face ten major environmental problems: water crisis, land desertification, destruction of the ozone layer, the greenhouse effect, acid rain, deforestation, soil erosion, species extinction, garbage and toxic chemicals pollution disaster. Acid rain is a global disaster across borders. Acid rain is a pH value of less than 5. 6 of the rain, sleet, snow, hail, dew precipitation. Environmental monitoring data show that due to the acidic substances in the atmosphere increased over most of the earths water area is sour, if not control, acid rain area will continue to expand, the harm to humans will also grow with each passing day. It has been confirmed that sulfur dioxide and two gasified nitrogen in the atmosphere are the main substances responsible for the formation of acid rain. Sulfuric acid accounts for 60% of the acid rain in the United States, nitric acid accounts for 32%, hydrochloric acid accounts for 6%, and the remainder is carbonic acid and a small amount of organic acid. Sulfur dioxide and nitrogen dioxide in the atmosphere are derived mainly from the combustion of coal and oil. They react with oxidants in the air to form acids that dissolve in rain water. According to statistics, the worlds annual emissions of sulfur dioxide into the atmosphere of about 1 tons, 50 million tons of nitrogen dioxide, so acid rain is mainly caused by human production activities and life. At present, the world has formed three major acid rain areas. Our country covers parts of Sichuan, Guizhou, Guangdong, Guangxi, Hunan, Hubei, Jiangxi,, Zhejiang, Jiangsu and Qingdao. The acid rain area, with an area of about 2000000 square kilometers, is one of the worlds largest acid rain areas. The area of acid rain area in China is expanding rapidly and the rate of precipitation acidification is very high, which is rare in the world. The other two acid rain areas in the world are centered in Germany, France, Britai