Question

Acid precipitation can be a major problem for some regions. What is the principle cause for this? How can it be prevented? What are some other technologies that we can utilize?

Answer 1

Acid precipitation or acid rain is due to increased release of carbon dioxide, sulphur dioxide or oxides of nitrogen in the atmosphere. These compounds react with carbon dioxide, oxygen, water etc present in air to form acidic compounds such as carbonic acid, sulphuric acid, nitric acid, which dissolve in water. These acidic compounds can be transported over larger distances by the air or wind movements and are released back to earth via rain, wind, fog etc. Acid precipitation can also settle as dry deposition on surfaces of vegetation, nasal tract of humans/animals causing intense damage. Soil erosion, washing of rain into water bodies will cause release of acid rain components into rivers/lakes, causing damage to aquatic and marine life. Acid rain has a pH less than 5.2.

Acid precipitation is majorly a result of human activities. Burning of fossil fuels by power plants, exhausts of cars, and other vehicles, manufacturing industries, oil refineries etc are human activities causing acid rain. Natural cause of acid precipitation is via volcanic eruptions.

Acid precipitation can be prevented by decreasing burning of fossil fuels. Regulating vehicle emission is one of the important methods to prevent acid precipitation. Instead solar energy or wind energy can be used to power them. Electricity obtained from water can also be used. Use of public transport or pooling vehicles (cars) can also reduce pollutant release. Use of natural gas instead of petrol/diesel and reduced use of fossil fuel in equipment is also advised.

Coal that is used of power plants should be of low sulphur variety to reduce its release. Washing the coal also reduces its sulphur content. Flue gas desulphurization is a technique used to remove sulphur dioxide released from flue or waste gases emitted by coal. Catalytic converters are now available that reduce the nitrogen oxide emission that occur from exhaust pipes of vehicles. Waters contaminated with acid rain can be neutralized by addition of lime. Limestone-calcium carbonate can be used to neutralize acidity in soil.