Tropospheric pollution occurs due to the presence of undesirable solid or gaseous particles in the air. The following are the major gaseous and particulate pollutants present in the troposphere:

$(i)$ Gaseous air pollutants : Oxides of sulphur, nitrogen and carbon, hydrogen sulphide, hydrocarbons, ozone and other oxidants.

$(ii)$ Particulate pollutants : These are dust, mist, fumes, smoke, smog etc.