4.11 Gas pollution

4.11 Gas pollution

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

1)      Sulphur dioxide – SO₂

The gas is added to the atmosphere when the combustion of fossil fuels (coal, oil and natural gas) occur in factories. (Sulphur dioxide is also produced from vehicles)

In the atmosphere Sulphur Dioxide combines with water vapour to produce Sulphuric Acid.

Sulphuric acid is found within water (in clouds) and when it rains it is known as acid rain.

Effects of Sulphur dioxide:

-Animals (the aluminium ions have an effect on fish; it thickens the mucus that lines the gills and reduces the fishes intake of oxygen from the water. The fish in turn suffocates and eventually dies.

-Lakes (the rain will forms streams, which will grow to form lakes. Acid rain reduces pH (make them acidic) and releases aluminium ions.

-Forests (trees and plants are 'burned' by the acid rain)(root system- Sulphuric acid causes the calcium and magnesium ions (Ca2+ and Mg2+) to be leeched out of the soil. The plant cannot obtain either magnesium or calcium; therefore yellowing of leaves occurs/the plant cannot grow.

2) Carbon Monoxide

It is produced when fossil fuels (especially gases) are burned with insufficient oxygen. CO combines with the hemoglobin in the red blood cells and forms a molecule called Carbonmino hemoglobin. It blocks the hemoglobin from carrying oxygen.

Effects of CO:

-Reduces oxygen circulation

- Toxic

- Too much of it can cause death

- It is very difficult to separate the Carbon monoxide molecule from the hemoglobin