All the developed countries of the world are discharging huge quantity of pollutants into the atmosphere. As a specific example of the most developed country like the U.S.A., the annual discharge of sulfur and nitrogen oxide into the atmosphere is about 50 million metric tons.
Combustion of large quantities of fossil fuels such as coal and petroleum is creating one of the most dangerous environmental problems for the future generation. Due to a series of chemical reactions these pollutants are generally converted into acids that fall on the earth with rain or snow.
The term for this precipitation is “acid rain”. The impact of acid rain is alarmingly serious. It is capable of causing increased leaching of nutrients and minerals from soil, loss of plant and fish life in lakes located in areas particularly sensitive to acid rain.
It is capable of causing considerable damage to the built environment, and burning holes in leafy vegetables.
All rainfall is slightly acid because water reacts with atmospheric carbon dioxide to produce a weak carbonic acid with a pH of 5.6. Remember that acid rain is defined as precipitation in which the pH is below 5.6.
The source of acid rain is air pollution which injects sulfur and nitrogen oxides into the atmosphere as a by-product of burning fossil fuels such as coal, oil and gas. Thus, it is clear that oxides of nitrogen and sulfur are mainly responsible for creating acid rain problem.