Five kinds of transition metal oxides supported on alumina and prepared by wetness impregnation were evaluated for the catalytic ozonation of toluene at room temperature and characterized by temperature-programmed reduction, temperature-programmed oxidation, N 2 adsorption-desorption, and X-ray photoelectron spectroscopy. The catalysts with a lower reduction temperature and less H 2 consumption showed a higher efficiency for ozone and toluene decomposition, such as NiO/Al 2 O 3 , CoO/Al 2 O 3 , and MnO 2 /Al 2 O 3 , while lower efficiency were observed on Fe 2 O 3 /Al 2 O 3 and CuO/Al 2 O 3 . Toluene decomposition efficiency was obviously dependent on ozone. Because of the low ozone to toluene concentration ratio, a CO 2 yield of less than 30% was obtained. At a toluene concentration of 666 mg/m 3 and an ozone concentration between 193 and 965 mg/m 3 , toluene conversion was found to vary from 15.2% to 46.7%. Additionally, we observed an increase in oxidation products and lattice oxygen on the catalyst surface. A preliminary investigation into the reaction pathway was undertook by in situ diffuse reflectance Fourier transform infrared spectroscopy. With regards to the formation of COO − , C=O, and C-O groups the high ozone concentration accelerated the transformation from COO − to C=O and C–O. The substance containing COO − remained unchanged at 573 K, while the substances containing C=O and C–O underwent oxidation at higher than 373 K. A possible reaction pathway is proposed based on these findings.