Abstract: Contaminated hot gases are first cooled and then the flow is divided between a plurality of identical modules for removal or contaminants. There are two stages of treatment in each module, starting with submergence of the flow under the surface of an agitated liquid neutralizing solution in a reservoir under a pair of counter rotating separator deflectors. Above the deflectors the flow is propelled upward through a venturi restrictor chamber, then into a collector pressure chamber. This completes the first stage of treatment, the second stage being the same as the first stage. Between these first and second stages the flow is passed through an electronic air cleaner. Upon leaving the second stage of treatment the cleaned gas flow joins the flows from the other modules in a fresh air distributor.