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

4. Acid rain
• Acid rains refers to strong mineral acids like
H2SO4, HNO3, H2CO3, 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.

5. Acid rain

6. 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.

7. 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.

8. Causes of acid rain

9. Mechanism of acid rain

12. 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.

13. 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.

14. 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.

15. 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.

16. Control strategies for acid rain
1. Use of low sulphur coal
2. Coal cleaning or coal gasification
3. Substitution of coal by other fuels
4. Alternative methods for power generation

17. Thank you