Pollution
These are chemicals produced by man's activities that cause harm to humans, other living organisms or to the environment. The increase in pollution over the last 150 years, is due to increase in population and the rapid growth of urbanisation and industry.
Air pollution
Gas Source Harmful effects
Carbon Dioxide Burning fuels
e.g. fossil fuels coal, oil, gas Heavy gas that does not allow burning or breathing if in high concentrations.
Normally kept at a constant level by the balance of respiration and photosynthesis
i.e. carbon cycle.
Removal of forests and pollution of the sea.
Killing algae may upset this balance.
Forms a weak acid (carbonic acid) pH5–6
in rainwater that dissolves out limestone and chalk from rocks, causing 'lime–scale' found in kettles and hot water pipes.
Contributes to global warming /greenhouse effect causing the raising of the Earth's temperature and possible melting of the polar ice caps and therefore the flooding of major cities at sea level.
Other greenhouse gases
Methane Rotting vegetation and rubbish dumps
and guts of certain herbivores e.g. cows
C.F.C. Some aerosols and refrigerators.
Carbon Monoxide Incomplete burning of fuels e.g. in petrol engines, old gas heaters, cigarette smoke Poisonous gas that reduces the ability of red blood cells to carry oxygen (combines with haemoglobin). Can cause death. In smokers can make one short of breath or affect development of the baby with smoking mothers
Acid rain Rain that has a pH of less than 5
Sulphur dioxide Burning of fossil fuels especially coal Dissolves rocks especially limestone used for statues and facing buildings.
Nitrogen oxides Burning of fossil fuels especially petrol Causes slow growth(stunting) of plants e.g. forests. Makes lakes acid so killing the fish.
Destruction of the ozone layer
C.F.C Some aerosols, refrigerants, foam furnishing, and packaging. Causes holes in the protective ozone layer, especially in Antarctica allowing harmful ultraviolet radiation through;
Supersonic flights In Humans can cause severe sunburn and skin cancers. In plants can reduce photosynthesis so reduce crop yield
Reduction of pollution
- Reduce the burning of fossil fuels by using less electrical energy,
not overheating homes, nor using cars unnecessarily but using public transport
instead. Generate electricity using alternative, renewable resources
e.g. wind, tidal, solar, biomass rather than using fossil or nuclear fuels. - Reduce air pollution by burning 'cleaner' fuels e.g. gas, 'smokeless' fuel, more efficiently.
- Reduce emissions by absorbing pollutants e.g. acid gases can be absorbed by alkalis in the chimneys.
Sort rubbish; separate out what can be recycled
- glass;
- paper and cardboard;
- aluminium and steel cans;
- different types of plastics
- biodegradable material that will rot on land–fill sites producing methane. (Instead, compost it to form fertilisers).