The destruction of low concentrations of toluene and cyclohexane in air streams using the combination of a novel multistage, non-thermal plasma reactor with either a MnO2 or a MnO2-CUO catalyst has been investigated. It is found possible to get complete destruction of the organic pollutant when the plasma and catalyst were combined. The different catalysts produced different outcomes in terms of the residual ozone in the outlet stream and the extent of oxidation to CO2. Neither of these compounds react to any measurable extent with ozone in the gas-phase nor are they decomposed by the catalyst at the temperature of the experiment. It is deduced that adsorption of ozone onto the catalyst surface and its subsequent dissociation into reactive atomic oxygen species is the key step in the heterogeneous destruction of toluene and cyclohexane. (C) 2009 Elsevier B.V. All rights reserved.