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What is Acid Rain?

If you want to know what acid rain is, and what its causes and effects are, you've come to the right place. Read on to know more...
Poushali Ganguly
Pollution has become one of the major problems that the world is facing today, and the different manifestations that it has are to deal with. Acid rain is one such form of pollution, which happens because of the harmful emissions released on the surface of the Earth due to human activities.
Air pollution ultimately leads to acid rain, as harmful gases which are mixed in the air also get combined with moisture and form acidic clouds, which lead to acid rain. Its sources are factories, vehicles, power stations, and industries, which burn fuel and produce harmful gases that contain sulfur dioxide or nitrogen oxide.
Acid rain primarily means the deposition of acidic elements in the form of precipitation, which can be snow, rain, dew, or fog. Normally, rain is acidic, though weak, as the pH level of rain is less than 7.
But when the concentration of pollutants increase in the atmosphere, the pH level further decreases, since pollutants react with the moisture present in the atmosphere and form strong acids like sulfuric and nitric acid.

Types of Acid Deposition

There are two types of acid deposition―one is wet and the other is dry. Wet deposition is the one which involves acid rain, or snow, or dew, whereas, dry deposition is when particles such as polluting gases, dust, and gaseous elements are just absorbed by the surface of the Earth or plant bodies.
They are not converted into acids until and unless they come in contact with water. In case of wet deposition, acids are removed from the atmospheric air, and are deposited on the surface of the Earth.

Natural and Human Causes

There are natural as well as detrimental human activities that lead to acid rain.

● Since this type of rain is caused by emissions of harmful gases, there are various natural causes, like volcanic eruptions and gaseous emissions from biological processes like decay and decomposition.
● Apart from this, human activities that result into acid rain are vehicle emissions and power generation plants that lead to the production and emission of sulfur and nitrogen oxides.
There are many preventive measures that have been taken, and which are still being implemented to stop pollution, like smoke treatment chambers, that treat the smoke before it comes out of a manufacturing unit. The smoke in the chamber is converted into gases which are not harmful to the environment.
Still, there are industries like coal power plants, which emit gases that pollute the atmosphere to the helm. But then, the infrastructure does not allow setting up a smoke treatment chamber.


There are adverse effects of acid rain, and it is better to deal with it when the problems are just in the process of making, when they are on a smaller scale. Acid rain causes the composition of the soil to be altered, which further results into the deterioration of plant life, and also disturbs the ecological cycle.
Existing plant life faces inhibition to grow in a healthy manner, since due to acid in the rain, they lose the nutrients present in the soil. Harmful elements are further added in the soil, that lead to the soil becoming unfit for plantation and cultivation.
Aquatic life also gets adversely affected, as the acids and other harmful substances in the rain get dissolved in the water, which leads to the death and destruction of aquatic life. If not death, it definitely leads to intoxication, which is passed on in the food cycle, and leads to the death and disease of many animals thereon.