a. Explain what is meant by the term ‘pollution’ with reference to air and water.

b. (i) Name an air pollutant produced by the burning of coal.

(ii) Name a different air pollutant produced by the combustion of petrol in a car engine.

c. Some of our drinking water is obtained by purifying river water.

(i) Would distillation or filtration produce the purest water from river water? Give a reason for your answer.

(ii) Which process, distillation or filtration, is actually used to produce drinking water from river water? Comment on your answer in comparison to your answer in c (i).

d. Power stations produce warm water. This causes thermal pollution as this warm water is pumped into nearby rivers.

(i) Why do power stations produce such large quantities of warm water?

(ii) What effect does this warm water have on aquatic life?