What is pollution? Name its four types, and describe the sources, effects and control of noise pollution.

1. 1 · Define. Pollution is an undesirable change in air, water or land that harms living things and property.
2. 2 · Four types. Air, water, soil and noise pollution.
3. 3 · Sources of noise. Industries, vehicles, aircraft, trains, loudspeakers, firecrackers and loud TV.
4. 4 · Effects.
   • Temporary or permanent hearing loss, and ringing in the ears.
   • Headache, irritability and poor concentration.
   • High blood pressure and disturbed sleep.
5. 5 · Control. Low volume, horns only in emergencies, silencers on machines, and a green belt of trees.
6. 6 · Close in one line. So noise is a pollutant because it harms health.

Scoring tip: Name the unit, the decibel, once; it shows the examiner you know how noise is measured.