2013—2015年上海市霾污染事件潜在源区贡献分析

Identification for potential sources for haze events in Shanghai from 2013 to 2015

统计分析2013—2015年上海市每个月不同空气质量等级天数比重,根据HYSPLIT(Hybrid Single Particle Lagrangian Integrated Trajectory)后向轨迹模型对3年内的12月份影响上海地区的污染气团进行了综合聚类分析和逐年聚类分析.在综合12次严重霾事件的后向轨迹基础上,结合上海实时公布的PM_(2.5)小时浓度资料,对潜在源贡献因子PSCF(Potential Source Contribution Function)和浓度权重轨迹CWT(Concentrationweighted Trajectory)进行分析与比较,研究重霾期间影响上海PM_(2.5)质量浓度的潜在源区及不同源区对PM_(2.5)质量浓度的贡献差异.结果显示,上海市3年期间12月份霾颗粒物外来源主要输送渠道为西北路径和北方路径,源自于西北方向的气团比重占总气团的50.4%,北方向的气团几乎都经过海洋后进入上海地区.影响上海地区PM_(2.5)质量浓度的潜在源区主要分布在安徽、江苏和山东地区,此外江西北部、浙江北部、河北南部及山西少部分地区也对重霾事件中的污染物颗粒有一定程度的贡献.

Hourly backward trajectories for air masses to the center of Shanghai in December of 2013-2015 were calculated using the HYSPLIT （ Hybrid Single Particle Lagrangian Integrated Trajectory） model. Potential Source Contribution Function （PSCF） and Concentration-weighted Trajectory （CWT） were employed to study the potential sources of PM2.5 and their possible impacts based on cluster analysis on the hourly PM2.5 concentrations during 12 serious haze pollution events in Shanghai. The results showed that haze events in Shanghai were strongly associated with the influence of air masses traveling over northwestern and northern China in December. Air mass from northwest contributed to the greatest fraction （50.4%） of all air masses to Shanghai. Anhui, Jiangsu and Shandong provinces were identified to make significant contributions to PM2.5 concentrations in Shanghai. Besides, the northern part of Jiangxi, the northern part of Zhejiang, the southern part of Hebei and a small part of Shanxi also made contributions to the air pollution in Shanghai.