Acid rain has been proven to damage forests, fresh water and soil, killing insects and aquatic life forms. It also causes damage to buildings and impacts human health. Many people don't know what acid rain actually is. Acid rain is any form of unusually acidic precipitation, low pH, higher than normal in amounts of sulfuric and nitric acid, occurring naturally and from artificial sources. Formed when gases react in the atmosphere with water, oxygen, and other chemicals (what is acid rain?). The only water that will not have some acidity is pure water. Pure water has a pH of 7 which is neutral; Ordinary, unpolluted rainwater has a pH of around 5.6. The acidity of rainwater comes from the presence of carbon dioxide, nitrogen oxide and sulfur dioxide. CO2 reacts with water to form carbonic acid. Nitrogen and water react during storms to form nitric oxide. The NO is then oxidized to form NO2. NO2 reacts with water to form nitric acid. As a result, the pH is lowered to become slightly acidic (acid rain). Acid rain can occur naturally in the environment, but the problem arises when human interaction causes the acidic levels. Decaying vegetation and erupting volcanoes release certain chemicals that can cause acid rain, but most acid rain falls because of human activities. When humans burn fossil fuels, sulfur dioxide (SO2) and nitrogen oxides (NOx) are released into the atmosphere. If large amounts of NO2 and SO2 are present in the atmosphere, the pH of rainwater will be significantly lowered. Nitric acid (HN03) can be associated with about a quarter of acid rain in the environment. Large quantities of NO gas are produced by the high temperature combustion of air that takes place in car engines and power plants....... middle of paper ...... uels. Other forms include nuclear power, hydropower, wind power, geothermal power and solar power. Nuclear and hydroelectric power are most widely used in the United States, while wind, solar, and geothermal power are not used on a large scale worldwide. Another possible solution is to have damaged environments repaired. Acidified lakes, streams, forests, and soils can take years, decades, or even centuries to heal. However, there are steps people can take to restore lakes and streams more quickly. Limestone or lime, which is a natural compound, can be added to acidic lakes to be used as a buffer to reduce acidity. This is not a licensing solution to the problem. However, liming allows fish to remain in a very acidic lake. The indigenous population can survive until the waterway is repaired..