The catalytic decomposition of ozone was investigated over Pd-Mn/SiO2-Al2O3 catalysts in the ground air. The catalysts were prepared by incipient wetness impregnation method and characterized by powder X-ray diffraction (XRD), thermo gravimetric (TG) analysis, and N-2 adsorption/desorption measurements (Brunauer-Emmet-Teller method). The influence of calcination temperature on the catalytic activities. and the lifetime test of the catalyst pretreated at 350 degrees C had been studied. XRD and TG results show that when calcined in the temperature range of 300-450 degrees C, manganese carbonate (MnCO3) is partly decomposed to MnOx (x = 1.6-2.0) species in the catalysts. However, when calcined at 500 degrees C, MnOx partly turns into Mn2O3 in the catalyst. The catalytic activity test indicates that the catalysts calcined at 300-400 degrees C exhibit the best performance for O-3 decomposition, and the completely conversion temperature of ozone (T-100) is in the region of 30-35 degrees C, which is lower than surface temperature of water tanks of running automobile. Under gas hour space velocity (GHSV) of 635,000 h(-1) and reaction temperature of 40 degrees C, after lifetime test for 80 h, the catalyst calcined at 350 degrees C keeps 90% conversion, which indicates that they have excellent ability to resist deactivation. The catalysts calcined at 300-400 degrees C show great potential to be applied at lower temperature, especially in winter and at the stage of automobile engine cold start. Crown Copyright (C) 2009 Published by Elsevier B.V. All rights reserved.