Oxides of Nitrogen, Sulphur and Carbon accumulate in the air which reacts with water and produce acids which come down to the surface of earth with rain. This is known as acid rain.
These acids can cause the decolorization of buildings, damages the sculpture, destroys the soil quality, result in weathering of rocks, affect the biotic components etc.
Case study: Taj Mahal:
One of the serious effects of acid rain is the corrosion of marbles- a phenomena known as marble cancer. A situation observed in the form of yellowing of marble of historical monument Taj Mahal due to emissions from a refinery in Mathura.
These emissions contain oxides of nitrogen, sulphur, carbon etc which results in acid rain. These react with marble thus decolourising it.
To save Taj mahal, Supreme Court has ordered to take step to control the air pollution by switching to cleaner fuels like CNG [compressed natural gas] and LPG [liquefied petroleum gas]. Also emissions from automobiles are controlled by switching to unleaded petrol in Taj zone.
Smog:
Smog is a mixture of smoke, fog and chemical fumes.
The combustion of fossil fuels increases the amount of suspended particles (unburnt hydrocarbons) in air.
Presence of high levels of all these pollutants causes visibility to be lowered, especially in cold weather when water also condenses in the air.
Regular breathing of such air results in the respiratory and heart diseases.
