The kinetic parameters of the lean oxidation of CH4 over alumina and ceria-alumina supported platinum catalysts in the presence of H2S and SO2 were derived in a stagnation point flow reactor at atmospheric pressure and at temperatures up to 1150 K. A novel methodology similar to that of plug-flow reactors was devised to calculate the best-fit values for frequency factors and activation energies for the proposed heterogeneous gas-solid reactions of oxidation. Doping the N-2-diluted CIL/air reactant flow with H2S or SO2 concentrations between 30 and 100 ppm had a significant promotional effect on the methane combustion rate. Al2O3 and CeO2/Al2O3 were shown to be inert with respect to the oxidation of CH4 to CO2, and also in the oxidation of SO2 to SO3 in air. Pt catalysed the oxidation of CH4, SO2 and that of H2S. A temperature window of conversion of SO2 to SO3 on the Pt-supported catalysts was found experimentally, and could be of practical use in combustion exhaust clean-up techniques. The repeated use of the foil resulted in a slight ageing effect for Pt/Al2O3. The presence of ceria in the washcoat helped prevent the loss of activity in CH4 oxidation by mitigating the extent of sintering of the Pt particles upon ageing. One-step and two-step chemical reaction mechanisms are proposed for the CH4 and the SO2 lean oxidations, respectively. (C) 2003 Elsevier Ltd. All rights reserved.