48.

What is the difference between pollutant and contaminant?

Pollutant: If the concentration of a substance already present in nature or of new substance increases by natural events or human activities to undesirable proportions so that it spoils the environment and reduces the quality of life or affects health, then it is regarded as a pollutant and this phenomenon is known as pollution. Sulphur dioxide, nitrogen oxides, carbon monoxide, pollen dust etc. are pollutants.


Contaminant: A substance which does not occur in nature but is introduced by human activity into the atmosphere and reduces the quality of life and affects our health is called contaminant. 
Pyrosulphuric acid (H₂S₂O₇) does not occur in nature. Pyrosulphuric acid leaked from a defective tank killed some persons and caused skin and breathing problems to many in Delhi some time ago. This man-made substance, because of its dangerous effects, is a contaminant.