Question

Suggest  measures  to  control  acid  rain.

DSERT Class 10 Science Ch 2 Environmental Issues

Answer 1

1. Afforestation (Growing more trees)
2. Replacing CFC (Chlorofluorocarbons) with less harmful substances like HFC (Hydrofluorocarbons)
3. Using less fossil fuels in automobile engines and replacing them with other substances.

Answer 2

1. Reduce amount of sulphur dioxide and oxides of nitrogen released into the atmosphere

i. Use less energy (hence less fuel burnt)

ii. Use cleaner fuels

iii. Remove oxides of sulphur and oxides of nitrogen before releasing

(a) Flue gas desulphurization

(b) Catalytic Converters

2. Use cleaner fuels

i. Coal that contains less sulphur

ii. “Washing” the coal to reduce sulphur content

iii. Natural Gas

3. Flue Gas Desulphurisation (FGD)

i. Removes sulphur dioxide from flue gas (waste gases)

ii. Consists of a wet scrubber and a reaction tower equipped with a fan that extracts hot smoky stack gases from a power plant into the tower

iii. Lime or limestone (calcium carbonate) in slurry form is injected into the tower to mix with the stack gases and reacts with the sulphur dioxide present

iv. Produces pH-neutral calcium sulphate that is physically removed from the scrubber

iv. Sulphates can be used for industrial purposes

4. Use other sources of electricity (i.e. nuclear power, hydro-electricity, wind energy, geothermal energy, and solar energy)

i. Issue of cost

5. Reducing the effects of Acid Rain by Liming

i. Powdered limestone/limewater added to water and soil to neutralize acid

ii. Used extensively in Norway and Sweden

iii. Expensive, short-term remedy