The gaseous pollutants can be controlled through the techniques of combustion, absorption adsorption and cold trapping.

(a)   Combustion: Though combustion is a major cause of is pollution but it helps in controlling pollution by converting hazardous pollutants like volatile organic compounds (VOC) and other gaseous hydrocarbons to CO₂ and H₂O.                                            If pollutants are organic in nature flame combustion is employed. Catalytic combustion is employed where low operating temperature is required.

(b)   Absorption/adsorption: Gaseous effluents are allowed to pass through scrubbers. This technique can be wet or dry. Some of solvents used for wet scrubbing are NaOH, Na2SO3, Ca (OH)₂

For dry Scrubbing activated carbon is used which attracts gases and vapour to its surface.

(c)    Cold trapping: All pollutants from air stream may be removed by cold trapping i.e. freezing them (gases or vapors) in collectors maintained at a low temperature. Fractionation is achieved by using bath (0⁰C) and last collector at a liquid nitrogen.