Analysis of the transport pathways and potential sources of PM10 in Shanghai based on three methods.

In this study, we investigated the transport pathways and potential sources of PM(10) in Shanghai based on PM(10) monitoring data recorded from 2006 to 2009 using three methods: backward trajectory cluster analysis, trajectory sector analysis (TSA) and potential source contribution function (PSCF). Seven clusters were generated from the backward trajectory cluster, and two potential sources were identified from the PSCF method. Among the seven clusters, three northerly clusters corresponded to the winter monsoon. The northerly air flow transported high-concentration PM(10) that had been emitted from northwestern sources, including Hebei, Shandong, Anhui and Jiangsu to Shanghai in winter and spring. The other three southerly clusters were associated with the summer monsoon caused by the Indian low and the Subtropical high over the western Pacific Ocean controlling the weather patterns of the eastern coastal area in summer. Corresponding to the southerly path, the PSCF method also identified a southwestern source including Zhejiang, Jiangxi and Fujian. The remaining eastern cluster, which represented the transition of monsoons, did not contribute much to the PM(10) concentration in Shanghai. According to the results of TSA, the relative PM(10) contribution to Shanghai of the northwestern source was approximately twice that of the southwestern source.