A Mazda E5 gasoline – powered engine operated on a dynamometer was used to investigate the PAH (Polycyclic Aromatic Hydrocarbons) and carbon emission. A 92–leadfree gasoline (92–LFG), a 95–leadfree gasoline (95–LFG) and a premium leaded gasoline (PLG) were used as tested fuels, Twenty one individual PAHs were analyzed by a gas chromatography/mass spectrometer (GC/MS), while the carbon composition of the aerosol samples were determined by an elemental analyzer. This study showed that the total – PAH concentration in the exhaust of 95–LFG was 1.29 and 1.33 times of magnitude higher than those of PLG and 92–LFG. With or without a catalyst converter system, the PAHs from primary sources mainly existed in the gas phase. Vehicles with a catalyst converter could reduce PAHs emission by more than 90%. In addition, it could reduce carbonaceous emission by more the 50% for total carbon (TC), 40% for elemental carbon (EC) and 60% for organic carbon (OC), respectively. The OC/EC rations were all greater than 1.0 for carbonaceous aerosols originated from the gasoline powered engine.