Acid deposition occurs when rainwater has a pH less than 5.6, primarily due to sulfur dioxide (SO2) and nitrogen oxides (NO2) from industrial activities and fossil fuel combustion. Acid rain has harmful effects on aquatic life, soil, and human health, including increased rates of respiratory illnesses. Efforts to control acid rain include reducing emissions of SO2 and NO2 and implementing mitigation strategies for affected ecosystems.

2. ACID DEPOSITION
 Defined by the pH of the liquid, If ph is Less
than 7 than it is acidic, more than 7 than it is
basic.
 Clean rain has a natural acidity of about 5.2
on the pH scale due to water reacting with
carbon dioxide in the air to form carbonic
acid
H2O + CO2 = H2CO3
2 H2O + H2CO3 = CO3
2− + 2 H3O+

3. ACID RAIN
Definition
 When the ph of rain water is less than 5.6, it
is called acid rain.
 The natural rain water has ph 5.6 at 20 C
due to formation of carbonic acid due to
dissolution of CO2 in water.

4. ACID RAIN
CO2 + H2O = H2CO3
 Oxygen, nitrogen and sulphur originating from
industrial operation and fossil fuel combustion
are the major causes of acid rain formation.
2SO2 + O2 = 2SO3
SO3 +H2O =H2SO4
2NO + O2= 2NO2
4NO2 +2H2O + O2 = 4HNO3

5. PROCESS OF ACID RAIN

6. CAUSES OF ACID RAIN
 SO2 and NO2 are mainly responsible for
forming of the acid rain.
 Main sources of the pollutants are
 Fossil fuel based power plants
 Smelting of sulfide ore
 Automobile exhaust
 Industrial plant using sulphuric and nitric
acid

7. EFFECTS OF ACID RAIN
 Low pH and high aluminum concentrations
can damage or kill fish and aquatic
populations.
 Soils can be damaged by acid rain.
 Increases the oxidation rate of metals such as
copper and bronze so things of metals and
copper are damage.

8. EFFECTS ON HUMAN HEALTH
 Elevated levels of fine
particles increase illness
and death from heart
and lung disorders such
as asthma.
 Reducing the nitrogen
oxides available to react
with volatile organic
compounds and form
ozone.

9. AREAS OF HIGHEST ACID RAIN
 Current problem areas
are:
 Eastern United States
 South Western Canada
 Eastern Europe
 Potential future problem
areas:
 Southern India
 West Africa
 Indonesia
 Thailand

10. CONTROL OF ACID RAIN
 Emission of SO2 and NO2 from industries
and power plants should be reduced by
using pollution control equipments.
 Limiting of lakes and soils should be done to
correct the adverse effects of acid rain.