2015年“十一”期间北京市大气重污染过程分析  

Analysis on a heavy air pollution process in Beijing during National Day holiday,2015

作　　者：李云婷[1,2] 王占山[1,2] 安欣欣[1,2] 李倩[1,2] 姜磊[1,2] 富佳明[1,2] 刘保献[1,2] 李令军[1,2] 张大伟[1,2] LI Yun-ting;WANG Zhan-shan;AN Xin-xin;LI Qian;JIANG Lei;FU Jia-ming;LIU Bao-xian;LI Ling-jun;ZHANG Da-wei(Beijing Municipal Environmental Monitoring Center, Beijing 100048, China;Beijing Key Laboratory of Atmospheric Particulate Monitoring Technology, Beijing 100048, China)

机构地区：[1]北京市环境保护监测中心,北京100048 [2]大气颗粒物监测技术北京市重点实验室,北京100048

出　　处：《中国环境科学》2016年第11期3218-3226,共9页China Environmental Science

基　　金：环保公益性行业科研专项(201409005);国家科技支撑计划课题(2014BAC23B03)

摘　　要：采用垂直观测、地面观测、PM_(2.5)化学组分观测和气团轨迹分析等手段,对2015年10月份北京市一次大气重污染过程进行了分析.结果表明,重污染时近地面层气溶胶消光系数升高,污染物主要积聚在600m以下.重污染期间气象要素特征为:风场弱,湿度大,地面受弱气压场控制,边界层高度极低.重污染期间不同站点PM_(2.5)浓度变化趋势和峰值出现时间较为一致;大部分时段PM_(2.5)中NO_3^-浓度明显高于其他组分;周边区域受重污染的影响面积相对较小,高浓度区主要集中在北京市及近周边地区.多手段的观测结果以及PM_(2.5)浓度与气象要素和各化学组分的相关性分析的结果均表明:区域传输,包括秸秆焚烧,对本次北京市重污染天气过程具有一定的影响,但本地机动车排放在不利气象条件下的积累、二次转化以及垂直方向空间的极端压缩是导致重污染的主要原因.A heavy air pollution episode in Beijing in October 2015 was analyzed through vertical observation,ground-based observation, monitoring data of chemical components of PM2.5 and back-trajectories of air mass. The resultsshowed that aerosol extinction coefficient increased significantly during the episode, indicating that air pollutantsaccumulated within 600m height from ground. Comparing with normal days, wind speed was weaker, relative humiditywas higher, surface pressure was lower and boundary layer height was lower during the episode. The variation and peakappearance were consistent among different monitoring sites, and NO3- concentration was higher than other componentsof PM2.5 in most time. In addition, the surrounding region of North China Plain affected by heavy pollution was relativelysmall, while PM2.5 accumulation in Beijing and its nearby region was more prominent. Multi-observations and correlationanalysis between PM2.5 and meteorological factors and chemical compositions showed that this episode was affected byregional transport to some extent, including straw burning. However, the accumulation and chemical reaction of local NO2emission under unfavorable meteorological conditions and extreme space compression in vertical direction was the maincause.

关 键 词：北京 重污染 空间分布 PM2.5化学组分 大气氧化性 

分 类 号：X51[环境科学与工程—环境工程]