Acid rain is very harmful to everything over a period of time. There are many forms of acid rain that are seen around the world. In wet weather, there is acid rain, acid snow, and acid fog. In dry weather there is acid gas and acid dust. Acid rain is formed by pollution, which is released into the air. Electric utility plants and other sources produce this type of pollution. The acids that are released into the air fall to the ground in different forms all over the Earth. The damage of acid rain causes worldwide environmental problems. Sulfur dioxide and nitrogen oxides are the main causes for the problems. These pollutants come from the burning of fossil fuels, such as coal, natural gas, and oil, and from certain kinds of factory distributions. These chemicals react with water and other chemicals in the air to form sulfuric acid, nitric acid, and other pollutants. These acid pollutants reach high into the atmosphere, travel with the wind for hundreds of miles, and eventually return to the ground by way of rain, snow, or fog, and as invisible "dry" forms. Damage from acid rain has been widespread in eastern North America throughout Europe, Japan, China, and Southeast Asia (Hart, John B.A., 1997). Acid rain takes nutrients and vital sources from soil, slows the growth of trees, and makes lakes unlivable for aquatic life. In cities, acid pollutants erode almost everything they touch, such as buildings and statues. Other chemicals and acids combine to form harmful smog, which attacks the lungs, causing illness and premature deaths.
Rain becomes acidic because of the gases, which dissolve in the rainwater to form various acids. Major contributing gases for acid rain are sulfur dioxide (SO2), oxides of nitrogen (NOx), carbon dioxide (CO2) and chlorine (CI2). The following reactions show the acid formation due to these gases (Cherrington, Brett; 1996):.
Sulfur dioxide reacts with water to form sulfuric acid (SO42-).