A study of the origin of individual PM2.5 particles in Shanghai air with synchrotron X-ray fluorescence microprobe

To identify the origin of individual PM2.5 particles in Shanghai air, synchrotron X-ray fluorescence microprobe at BL-4A beamline of Photon Factory was applied to analysis of the individual PM2.5 particles. By using excitation energy of 17.4 keV, trace elements of environmental concern in the fine particles, like S, Cr, Sr and Pb can be detected. Only 60 s of irradiation was needed to measure each of the individual PM2.5 particles. The result of this study shows that the most of analyzed PM2.5 particles were derived from vehicle exhaust, metallurgic emissions and power plants. This result is consistent with the morphological observation of PM2.5 particles obtained by scanning electron microscopy.