Abstract:The pollution level and temporal distribution characteristics of volatile organic compounds (VOCs) were analyzed together with trace gases in autumn of 2012in Shanghai. The hourly average concentration of VOCs is 63.64′10-9 and the NMHCs accounted for 67.43%. The ratio between typical VOCs species showed that the air masses observed in this study were characterized as photochemical-aged and this was further illuminated by the analysis on diurnal variation of ethane/acetylene (E/E) and acetylene/CO(E/C). Here we also studied the origination of air masses during the observation with backward trajectory and cluster analysis. The value of E/E was found to be much lower in air masses originated from continent than that form ocean, while there was no difference between the benzene/ toluene values.