Despite the airlines and regulators insisting that filtering aircraft cabin air is still not technically possible, solutions do already exist and a limited number are already in operation on airliners.

Filter manufacturers Pall Corporation presented a paper at the 40th International Conference on Environmental Systems detailing various filtration solutions.

Pall Corporation - Cabin air filtration systems

Contradictions

It seems the airlines and regulators are having trouble getting their stories straight ...

The BAE Systems / Quest AirManager system that is installed on some Avro RJ and Boeing 757 aircraft uses non-thermal plasma oxidation technology as discussed in the document. For this particular system Pall do say that for its success it is vital that the nature of airborne contaminants is known. While various regulating authorities admit that cabin air contamination does occur, their official research has still not managed determine the composition.

A recent leaked document to the German press from the Bundesverband der Deutschen Fluggesellschaften, BDF (Association of German airlines) told its members that cabin air filtration is not technically possible due to the high pressure and temperature of the bleed air. However, Lufthansa CityLine has already installed the Quest system on some of its Avro RJ85 fleet with (and subsequently removed them after an increase in fume event reports) and Condor is looking to install the same system on its Boeing 757 aircraft.