Acid Rain: When the particles of Nitric acid, Sulphuric acid and such like other acids, afloat in the air, mix up with the rain water and drop down on earth, such a shower is called Acid rain.
Particles of sulphur and nitrogen oxide come along with the gas and smoke emanated from the auto-vehicles and workshops and mills are collected in the air.
The more the air pollution increases, the more these injurious chemical particles increase in the air simultaneously increasing the threat of Acid rain.
Why Acid rain is harmful? Acid rain tends to deter agriculture on one hand and it widely harms the forests, fisheries etc. on the other hand. This kills trees in forests and makes fresh water too much acid for fish and water habitats to live in. It also damages the stone house of building.
What causes Acid rain? Acid rain is created by the action of gases released in to the air from factories and cities. Burns of fossil fuels increases the chemistry in the air, and form stronger acids. These gases form, strong acids in the water vapor in clouds, and fall as acid rain on forests and lakes.
How does Acid rain occur? Generally, the oxygen and the dust particles in the atmosphere react photo-chemically with the water-droplets floating in the air and produce sulphur dioxide. This besides, the fossil-fuel combustion, mixing of air with the sulphur-dioxide released from the metal-extraction ovens and preparations of Sulphuric acid and Nitric acid through photo-chemical reaction of Nitrogen oxide coming out from the auto vehicles.
These, by retracting with the water droplets floating in the air create dew and frost and rain-drops which come down on earth in the shape of acid rain.