Question

What is an atmospheric inversion and how does it trap air pollutants?

Answer 1

Due to atmospheric inversion in which temperature increase with height (opposite to normal condition); air pollutant unable to get energy to move upward.

Explanation:

We live in troposphere having property that temperature decreases with height (that is why we experience decrease in temperature on hill stations). But due to certain weather situation sometimes (or many times) it happens that temperature increases with height.

Now consider some pollutant close to the ground let say at Temperature=30 degree centigrade. Few inches above temperature is 30.5 degree centigrade. Now what happens that pollutants do not have enough energy to move at higher temperature from lower temperature (as temperature increases with height).
So to move any pollutant or moisture to move upward; temperature should be decreased with height.