Estimation of potential source regions of PM2.5 in Beijing using backward trajectories

Possible source regions of the PM2.5 mass concentrations in Beijing, China have been identified using the Potential Source Contribution Function (PSCF) analysis based on the backward trajectory modeling. Five-day backward trajectories for the arrival of air masses to the ground observation station at Chaoyang Olympic Sports Center were calculated, using the Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model in 2013. The PSCF results demonstrated that regional sources in different seasons could be one of the crucial contributors to PM2.5 mass concentrations in Beijing, especially in the winter season. Compared PSCF results with the MODIS fine-mode aerosol optical thickness (AOT(fine)), the regions showing high AOT(fine) especially the Southern Hebei, Northern Henan and Southwest Shandong are the significant potential PM2.5 contributors to Beijing. Environmental authorities may use the derived models and results for pinpointing the source areas, for improving air quality in Beijing City.