北京市冬季典型重污染时段PM_(2.5)污染来源模式解析  

Model Analytic Research of Typical Heavy PM_(2.5) Pollution Periods in Winter in Beijing

作　　者：陈云波[1] 徐峻[1] 何友江[1] 杜晓惠[3] 唐伟[1] 孟凡[1,2] 

机构地区：[1]中国环境科学研究院,环境基准与风险评估国家重点实验室,北京100012 [2]南京信息工程大学大气环境与装备技术协同创新中心,江苏南京210044 [3]山东师范大学地理与环境学院,山东济南250014

出　　处：《环境科学研究》2016年第5期627-636,共10页Research of Environmental Sciences

基　　金：国家科技支撑计划项目(2014BAC06B05);国家电网公司科技项目(SGHAJYOOGHJS1500029);国家环境保护公益性行业科研专项(201309071)

摘　　要：为了探究近年来北京市PM_（2.5）污染区域来源规律和重污染累积过程中PM_（2.5）的生成途径,利用第三代三维空气质量模型CAMx的颗粒物源示踪（PSAT）和过程分析（PA）技术,模拟计算了北京市2013年和2014两次冬季典型重污染时段PM_（2.5）的源-受体关系和物理、化学过程对PM_（2.5）的生成贡献.结果表明：在区域来源贡献中,随着空气污染等级由优升至严重污染,外地PM_（2.5）贡献率从42.9%升至67.4%,本地贡献率由57.1%降至32.6%,其中外地二次PM_（2.5）贡献率从20.2%升至39.8%,为北京市重污染时段的主要贡献因子;在外地贡献中,廊坊市、山东省、天津市、唐山市的贡献率较大,分别为3.2%-4.7%、3.8%-7.5%、3.6%-5.8%、2.2%-3.2%.PA分析结果表明：在不利气象条件（持续性的逆温层结）下,南边界的输送在重污染过程中起到了重要作用,对ρ（PM_（2.5））增长的贡献速率可达10μg/（m3·h）.此外,本地化学转化在重污染时段对ρ（PM_（2.5））爆发性增长的贡献率也可以达到40.0%,其中特殊天气条件下二次PM_（2.5）生成贡献的显著增加是造成ρ（PM_（2.5））出现峰值的主要原因.研究显示,随着污染程度的加重,北京市受区域性污染的影响逐渐加大;在重污染过程中,不利气象条件下的本地化学转化与水平输送对近地层ρ（PM_（2.5））峰值的出现与维持发挥了重要作用.Particulate source apportionment technology（ PSAT） and process analysis（ PA） of CAMx were used for understanding the regional source contributions and formation processes of PM_（2.5）in Beijing during heavy polluted periods in recent years. With the increasing of the air quality index from Ⅰ to Ⅵ,the modeling results showed that the regional contribution to PM_（2.5）increased from 42. 9% to67. 4%,while the contribution of local emissions decreased from 57. 1% to 32. 6%. The secondary portion of PM_（2.5）became the major contributing factor during heavy PM pollution events,with the contribution ranging from 20. 2% to 39. 8%. Among the source regions in Beijing,Langfang,Tangshan in Hebei Province,Shandong Province and Tianjin City accounted for large fractions,supplying 3. 2%-4. 7%,3. 8%-7. 5%,3. 6%-5. 8% and 2. 2%-3. 2%. PA modeling results for two heavily polluted events were analyzed by PA process tool. The results indicated that the ratio of local chemical transformation contributed up to about 40. 0% of incremental PM_（2.5）concentration during the heavy pollution event.Transportation from the southern bounder of Beijing also played an important role,contributing 10 μg/m3incremental concentration of PM_（2.5）in one hour. Chemistry conversion during the night under extremely adverse meteorological conditions was the most important reason for the appearance of the peak concentration ofPM_（2.5）,accounting for about 40. 0% of the PM_（2.5）rapid increment. This study concluded that the heavier the pollution in Beijing,the larger the influence of regional pollution. The local chemical conversion and horizontal transmission of PM_（2.5）play important roles in the appearance of the peak concentration of PM_（2.5）during heavy pollution.

关 键 词：PM2.5 源解析 CAMX 颗粒物源示踪技术 过程分析 

分 类 号：X513[环境科学与工程—环境工程]