Question

why are pollutants found in the lower layers of atmosphere

Answer 1

The troposphere is the lowest layer of the Earth's atmosphere. The air is very well mixed and the temperature decreases with altitude.

Air in the troposphere is heated from the ground up. The surface of the Earth absorbs energy and heats up faster than the air does. The heat is spread through the troposphere because the air is slightly unstable.

Weather occurs in the Earth's troposphere. that is why air pollutants found in lower layer