State the sources and effects of the following gases:

(i) Carbon dioxide

(ii) Methane

(iii) Water vapour

(i) Carbon dioxide

Sources :

1. Burning of fossil fuels like coal, natural gas and petroleum.
2. Industrial processes like the manufacture of lime and those seen in fermentation units.
3. Biological decay of plants.
4. Respiration by animals, humans beings and plants.

Effects :

1. Carbon dioxide is a greenhouse gas.
2. It has the largest contribution of about 50% towards greenhouse effect.

(ii) Methane

Sources :

1. Anaerobic decomposition of organic matter in soil, water and sediments.
2. Incomplete combustion of fossil fuels.

Effects :

1. Methane is a greenhouse gas.
2. It has the second largest contribution of about 19% towards greenhouse effect.

(iii) Water vapour

Sources :

1. Burning of hydrocarbons.
2. Evaporation from water bodies.
3. Transpiration from plants.

Effects :

1. Water vapour is a greenhouse gas.
2. It contributes 2% towards greenhouse effect.