利用轨迹模式研究重庆主城区冬季PM2.5污染特征

Study on pollution characteristics of PM_(2.5) in Chongqing urban area in winter with backward trajectories

利用轨迹聚类法,对2014年12月至2015年1月重庆主城区上方的后向轨迹气团进行聚类分组,分析重庆主城区气团来源。结合重庆主城区PM_(2.5)小时浓度资料,分析污染较重时重庆主城区后向轨迹特征。最后结合潜在源贡献因子分析(PSCF)法和浓度权重轨迹分析(CWT)法定性与定量分析了重庆主城区PM_(2.5)的潜在源区。结果表明,重庆本地气团占60.9%,不利于本地污染物的扩散;超过60%的污染事件是由本地颗粒物聚集造成的;重庆主城区颗粒物其潜在污染源区,以西藏与四川交界处、四川东部、贵州北部以及重庆本地为主。

Backward air mass upon Chongqing urban area from December 2014 to January 2015 was categorized using trajectory clustering method to analyze its main sources. Combined with the concentration of PM2.5 hourly of the urban area, the characteristics of backward trajectories during heavy pollution period were analyzed. Finally, potential sources of PM2.5 were qualified and quantified with PSCF and CWT. Results showed that local air mass accounted for 60.9 %,which would prevent diffusion of local PM2.5 pollution, more than 60 % heavy pollution eventsarose from local particle aggregation and the junction of Sichuan and Tibet, eastern Sichuan, northern Guizhou and Chongqing local were potential pollution sources of PM2.5.