Abstract:PM2.5 samples in Beijing were collected during the Lantern Festival of 2014. Morphologies and elemental compositions of individual particles were determined by Field Emission Scanning Electron Microscopy coupled with Energy Dispersive X-ray Spectrometer (FESEM-EDX). Size distribution of individual particles in FESEM images were further analyzed by an image analysis system. The result shows that soot aggregate, mineral and fly ash were dominant particles. Particles generated by the fireworks and firecrackers in Beijing can lead to PM2.5 concentrations increase during the Lantern Festival. The particle number firstly behaved one increase and then decrease. Particle size mostly displayed less than 0.7μm during the lantern festival. However, the particle number with the diameter >0.7μm in the heavy pollution period was significantly higher than them in the light pollution period.