Acidic gases like carbon dioxide and Sulphur dioxide dissolves with the water within the rain cloud and causes acid rain. Acid Rain is formed due to emission of poisonous gases into the atmosphere by human activities.
Fossil-fuelled powered stations and oil/diesel vehicles radiate synthetic pollutants– chiefly sulphur dioxide (SO2) and nitrogen oxides (NOx) – which when mix with the water in the air react and turn acidic.
Though pollution due to man made activities are primarily responsible for the acid rain, however, some natural phenomenon also contribute in turning rain acidic. Acid gases are emitted in the atmosphere from volcanoes. Acidic sites have been identified in glacial ice thousands of years old in remote parts of the globe.
How Rain Becomes Acidic:
Sulphur dioxide and nitrogen oxides from industry and vehicles are released into the atmosphere. Electrical power generation through coal based power plant is the significant source of acidic gases into the atmosphere.
The gases are carried on the wind to higher ground, towards rain clouds.
Upon combining with the water vapour (water and oxygen) in the rain clouds, the gasses react to form weak but potentially damaging acid. Sulphur dioxide from industry becomes sulphuric acid.
When acid rain falls it can damage plant life, infiltrate waterways and erode buildings and statues.
Negative Effects of Acid Rain:
All rainwater is a little bit acidic, because the carbon dioxide present in the atmosphere dissolves in water and forms carbonic acid. Stronger acid rain, however, can damage stone structures and can also be harmful to crops, as well as polluting waterways.
The negative effect of acid rain on limestone statues is all too common. Acid rain damages buildings, trees and harms life in rivers and lakes. It also causes chemical weathering of rocks to happen much faster than normal.