Pollutants such as SO2, H2S, CO2, NOx, HF, etc. or recyclable materials such as ammonia (NH3) can be removed from gas streams.
In many processes gas must be cooled prior to further handling or before release into the atmosphere.
During the direct condensation processes vapors and vapor mixtures get in contact with a cooling agent with temperature below the dew point.
Biological processes for air purification use microorganisms to convert odours and other exhaust air pollutants into non-toxic substances such as CO2 and water are converted.