Acid rain is a rain that is unusually acidic, meaning that it possesses elevated levels of hydrogen ions (low pH). It causes harmful effects on plants, aquatic animals and infrastructure. It is caused by emissions of Sulfur dioxide and nitrogen oxide, which react with the water molecules in the atmosphere to produce acids. Nitrogen oxides can also be produced naturally by lightning strikes, and Sulfur dioxide is produced by volcanic eruptions. The chemicals in acid rain can cause paint to peel, corrosion of steel structures such as bridges, and weathering of stone buildings and statues.
The principal cause of acid rain is Sulfur and nitrogen compounds from human sources, such as electricity generation, factories, and motor vehicles. Thermal electrical power generation is among the greatest contributors to gaseous pollutions that are responsible for acidic rain. In the past, factories had short funnels to let out smoke but this caused many problems locally; thus, factories now have taller smoke funnels. However, despite of these taller stacks causes pollutants to be carried farther, causing widespread ecological damage.
