An apparatus for the decontamination of air, the apparatus comprising a housing (1) having an air inlet (4) and an air outlet (6) with an air passage (2) there between, means (20) for directing a stream of air through the housing, the housing containing a non-thermal plasma cell (30), an ultraviolet emitting device (40) and an ozone depletion catalyst (42), the non-thermal plasma comprising an anode (32), a dielectric (32) and a cathode (33), the cathode being in the form of a meshed enclosure which surrounds the ultraviolet emitting device and ozone depletion catalyst to form a reaction chamber and Faraday cage. The non-thermal plasma cell may also be provided as a columnar cell for forming an array of cells and the dielectric may comprise water droplets to improve the efficiency of the device.