Characteristics of element concentration of daytime and nighttime PM2.5 in the suburbs of Shanghai using Synchrotron XRF

The characteristics of daytime and nighttime suburbs PM_2.5 in Shanghai were analyzed by synchrotron based X-ray fluorescence during the period of October, 2006 and November, 2007. The mass concentrations of nighttime PM_2.5 was approximately two times that of daytime PM_2.5. Some elements, such as Zn, Cu, Mn, Cl were found enriched at night. The local sources might have significant contribution to the nighttime PM_2.5 pollutions.