Seasonal variations of transport pathways andpotential sources of PM
Yuan Chen, Shaodong Xie, Bin Luo
Frontiers of Environmental Science & Engineering
2018,
Volume 12,
Issue 1,
doi:
10.1007/s11783-018-1009-z
Abstract:
Seasonal pattern of transport pathways and potential sourcesof PM in Chengdu during 2012–2013were investigated based on hourly PM data,backward trajectories, clustering analysis, potential source contributionfunction (PSCF), and concentration-weighted trajectory (CWT) method.The annual hourly mean PM concentrationin Chengdu was 97.4 mg·m . 5, 5, 5 and 3 mean clusters were generatedin four seasons, respectively. Short-distance air masses, which travelledwithin the Sichuan Basin with no specific source direction and relativelyhigh PM loadings (>80 mg·m ) appearedas important pathways in all seasons. These short pathways indicatedthat emissions from both local and surrounding regions of Chengducontributed significantly to PM pollution.The cities in southern Chengdu were major potential sources with PSCF>0.6and CWT>90 mg·m . The northeastern pathway prevailed throughoutthe year with higher frequency in autumn and winter and lower frequencyin spring and summer. In spring, long-range transport from southernXinjiang was a representative dust invasion path to Chengdu, and theCWT values along the path were 30-60 mg·m . Long-range transportwas also observed in autumn from southeastern Xinjiang along a northwesterlypathway, and in winter from the Tibetan Plateau along a westerly pathway.In summer, the potential source regions of Chengdu were smaller thanthose in other seasons, and no long-range transport pathway was observed.Results of PSCF and CWT indicated that regions in Qinghai and Tibetcontributed to PM pollution in Chengdu aswell, and their CWT values increased to above 30 mg·m in winter.
Keywords：
Transport pathway
Backwardtrajectory
Clustering analysis
Potential source
Chengdu
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