This is a form of pollution depletion in which SO2 and NOx produced by the combustion of fossil fuels are transported over great distances through the atmosphere and deposited via precipitation on the earth, causing damage to ecosystems that are exceedingly vulnerable to excessive acidity. Therefore, it is obvious that the solution to the issue of acid rain deposition requires an appropriate control of SO2 and NOx pollutants. These pollutants cause both regional and transboundary problems of acid precipitation.
Recently, attention is also given to other substances such as volatile organic compounds (VOCs), chlorides, ozone and trace metals that may participate in a complex set of chemical transformations in the atmosphere resulting in acid precipitation and the formation of other regional air pollutants. A number of evidences that show the damages of acid precipitation are reported by Dincer and Rosen .
It is well known that some energy-related activities are the major sources of acid precipitation. Additionally, VOCs are generated by a variety of sources and comprise a large number of diverse compounds. Obviously, the more energy we spend the more we contribute to acid precipitation; therefore, the easiest way to reduce acid precipitation is by reducing energy consumption.