Tropospheric pollution is caused by the presence of undesirable chemicals in the troposphere’s lowest layer.

Nitrogen oxides, sulphur oxides, carbon, and hydrocarbons are the most common pollutants.\

• Oxides of nitrogen (NO₂, NO) and sulphur (SO₂ and SO₃) which are formed due to the burning of coal, automobile fuel and other fossil fuels, form nitric acid (HNO₃) and sulphuric acid (H₂SO₄) by reacting with water in the presence of atmospheric oxygen. This results in ‘Acid rain’.

2SO_2(g) + O_2(g) + 2H₂O_(l) $\to$ 2H₂SO_4(aq)

4NO_(g) + O_2(g) + 2H₂O_(l) $\to$  4HNO_3(aq)

Plants, crops, and trees are all harmed by acid rain. In humans, it also causes respiratory difficulties.

Hydrocarbons are carbon and hydrogen-containing chemicals. Carbon oxides are formed when they burn. They are naturally carcinogenic and are also considered significant pollutants.
Carbon monoxide (CO) is toxic and can potentially be deadly when it interacts with the haemoglobin in our blood. Despite the fact that carbon dioxide (CO2) is not harmful in and of itself, it contributes to global warming by trapping additional solar rays. As a result, the earth’s temperature rises as a result of the heating effect.
Particulates such as dust, smoke, fume, and mist obstruct our nasal passage and are thus deemed harmful.