4.11 understand the biological consequences of pollution of the air by sulphur dioxide and carbon monoxide

SULPHUR DIOXIDE ( SO2 gas )
- is produced in the combustion of fossil fuels and also by vehicles in the combustion of petrol
- when SO2 gas is produced it reacts with water vapour in the air and forms sulphuric acid which is found     in the water that condenses as clouds, this is known as acid rain.
EFFECTS OF ACID RAIN
acid rain effects plants and animals in a variety of ways
PLANTS
- the trees are 'burned' from the direct effect of the sulphuric acid, in areas where there is acid rain the tops of the trees are often found dead.
- when there is acid rain calcium ions and magnesium ions -which are used by the plant in the process of making chlorophyll- are 'leached' from the soil meaning that the plant can no longer obtain those substances  making the plant suffer from chlorosis ( the yellowing of the leaves )
ANIMALS
- the acid rain precipitation will form streams leading into the rivers and lakes, reducing the PH in the water; which releases aluminium ions effecting the fish in the lakes and rivers, aluminum ions thickens the mucus which lines the fishes gills reducing the efficiency in which the fish can take in oxygen, killing the fish.

CARBON MONOXIDE    CO
is produced when fossil fuels are burnt with insufficient amounts of oxygen.
- carbon monoxide combines with haemoglobin in red blood cells, forming carbamino haemoglobin which blocks the haemoglobin from carrying oxygen, reducing oxygen circulation, this is toxic and can be fatal