What is acid rain and its causes?

Acid rain is precipitation with high levels of sulphuric and nitric acids, primarily caused by industrial pollution.

Acid rain is a term that describes any form of precipitation with acidic components, such as sulphuric or nitric acid, that fall to the ground from the atmosphere in wet or dry forms. This can include rain, snow, fog, hail or even dust that is acidic. The main cause of acid rain is human activities, particularly the burning of fossil fuels and other industrial processes that release sulphur dioxide (SO2) and nitrogen oxides (NOx) into the atmosphere. These gases can rise very high into the atmosphere, where they mix and react with water, oxygen, and other chemicals to form more acidic pollutants, known as acid rain.

Sulphur dioxide and nitrogen oxides dissolve very easily in water and can be carried very far by the wind. As a result, the two compounds can travel long distances where they become part of the rain, sleet, snow, and fog that we experience on certain days. While a small portion of the SO2 and NOx that cause acid rain is from natural sources such as volcanoes, most of it comes from the burning of fossil fuels. The major sources of SO2 and NOx in the atmosphere are: burning of fossil fuels in power plants, cars, lorries, and other vehicles and heavy equipment; and manufacturing, oil refineries, and other industries.

Acid rain has significant effects on the world environment and public health. It can damage buildings, historic monuments, and statues, especially those made of rocks, such as limestone and marble, that contain large amounts of calcium carbonate. In the environment, acid rain can damage forests and soils, harm marine life in rivers and seas, and eventually affect the food chain. It also contributes to air pollution that can cause health problems in humans and animals.