The present invention provides an economical and efficient system for the catalytic conversion of ozone, particularly in airplane bleed air. The present invention comprises a washcoat on a single surface layer, wherein the washcoat may contain an active metal oxide which is active for ozone conversion where the metal oxide comprises a transition metal. Alternatively, the system may comprise a refractory metal oxide washcoat into which a transition metal active for ozone conversion is impregnated.