Many damages to the plants, buildings and other structures are contributed to the acid rain. Acid rain is relatively a new phenomena because it is caused by gases from burning coal and natural oil. You may have noticed that the air is cleaner and fresher after a rain. Have you wondered what happens to the fumes and gases and particles in the air during a rain. They are all washed by the rain. The highest amount of such pollutants are absorbed by the rain drops in the first few minutes of a heavy rain.

When gases such as sulfur dioxide (SO2) and Nitrogen oxide (NO and NO2) are absorbed by the rain, they are converted to sulfurous acid and nitrous and nitric acids. That is what we call acid rain.