Acid rains

air pollution and control
acid rains
global effects of air pollution
remedial measures for acid rains

1. Acid rains Ravi Kumar GARRE

2. Contents covered What is acid rain? Causes of acid rain Mechanism of acid rain Effects of acid rain Control strategies for acid rain

3. Acid rain Acid rains refers to strong mineral acids like H 2 SO 4 , HNO 3 , H 2 CO 3 , etc. which bring down the pH in atmospheric precipitation. Since the last few decades, the rain water getting acidic in nature, it is the result of air pollution. When the rain water’s pH falls below 5.6, then it is said to be acid rain. The acid rain leads to acid deposition on surfaces, vegetation, water bodies, soil, etc.

4. Acid rain

5. Causes of acid rain The problem of acid deposition is primarily related to the use of high sulphur coal and oil. The combustion of such coal and oil produces SO2 and NOX into atmosphere. The gases react with water vapour/ humidity and produce sulphuric acid and nitric acid in atmosphere. These acids reaches earth surface along with precipitation is called as acid rain. The acids in atmosphere react with ammonia and other cations produce sulphates and nitrates, which fall on earth in the form of particulates.

6. Causes of acid rain These acids reaches earth surface along with precipitation is called as acid rain. The acids in atmosphere react with ammonia and other cations produce sulphates and nitrates, which fall on earth in the form of particulates.

7. Causes of acid rain

8. Mechanism of acid rain

9. Effects of acid rain Acidification of lakes and rivers Kills aquatic animals, plants and fishes. Affects aquatic eco-system. Kills bacteria, green algae and other biota. Leads to water pollution. Improves concentrations of heavy metals like lead, cadmium, copper and zinc in water bodies.

10. Effects of acid rain Acidification of soils Soils with lime frequently lose their fertility by acidification. Leads to loss of nutrients like Potassium, Phosphorous, Calcium and Magnesium. Spoils the metals like Al, Zn, Mn , etc. from soils. Affects agricultural production so greatly.

11. Effects of acid rain Effects on materials Cause physical damage to buildings, monuments, bridges and other structures by corrosion. Causes erosion of stones. Undergo chemical reactions with limestone. Causes weathering of surfaces of sand stone. Affects several items like paper, fabrics, leather and wood very badly.

12. Effects of acid rain Health effects Causes skin cancer and other skin diseases. Can enter very deep in lungs and causes lung cancer. Increased acidity in water, air, soil and plants. So, automatically the food produced will become so dangerous.

13. Control strategies for acid rain Use of low sulphur coal Coal cleaning or coal gasification Substitution of coal by other fuels Alternative methods for power generation

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