2014年10月北京市4次典型空气重污染过程成因分析  

Analysis about the Characteristics and Formation Mechanisms of Serious Pollution Events in October 2014 in Beijing

作　　者：程念亮[1] 李云婷[1] 张大伟[1] 陈添[2] 徐文帅[1] 孙峰[1] 董欣[1] 

机构地区：[1]北京市环境保护监测中心,北京100048 [2]北京市环境保护局,北京100048

出　　处：《环境科学研究》2015年第2期163-170,共8页Research of Environmental Sciences

基　　金：北京市科技计划课题(Z131100006113009);国家环境保护公益性行业科研专项(201409005)

摘　　要：采用数值模拟与观测资料相结合的方式,对2014年10月北京市4次典型空气重污染过程的大气环境背景、气象条件和形成原因进行了分析.结果表明,京津冀区域稳定的气象条件是形成空气重污染的主要原因,4次重污染过程大气条件均不利于污染物扩散,表现为大气层结稳定,近地层逆温（平均逆温强度为2.26℃/100 m）明显,风速（平均值为1.52 m/s）小,相对湿度（平均值为80.75%）大.在4次重污染过程中8—11日污染最重,ρ（Pm^2.5）日均值平均为264μg/m^3,并且区域输送对北京贡献率最大,平均值为63.75%;24—25日污染程度次之,逆温最强,逆温强度达5.94℃/100 m;18—20日重污染中北京ρ（Pm^2.5）高值（〉200μg/m^3）区主要集中在该市西北部地区;30—31日污染相对较轻,ρ（Pm^2.5）日均值最高只有154μg/m^3.数值模拟表明,在4次典型重污染过程中,来自南方（包括河北、河南和山西西部等地）的外来污染物输送对北京Pm^2.5贡献较大,外来贡献率分别在42.36%-69.12%之间,同时北京本地也存在较强的二次无机盐及有机物转化过程.Atmospheric environmental background data,weather conditions and formation mechanisms of four typical air pollution episodes in Beijing in October 2014 were investigated by combining observed data and result from the numerical model CAMx.The results showed that the occurrences of heavy air pollution resulted mainly from stable regional or local atmospheric conditions.Observed heavy pollution episodes were characterized by a stagnant atmospheric structure with average wind speed of 1.52 m/s,high humidity of 80.75% and,large inversion strongth of 2.26 ℃ /100 m which were disadvantageous to the dispersion of air pollutants.The air pollution in October 8^th-11 ^st episode was most serious with daily average Pm^2.5concentration of 264 μg/m^3and highest contribution from regional chemistry transport（63.75%）,the second most serious pollution episode was October 24^th-25^ thduring which there was a strongest inversion（5.94 ℃ /100m）.During the October 18th-20 thheavy pollution episode,high concentrations Pm^2.5（above 200 μg/m^3） were found mainly in the northwest part of Beijing.The heavy air pollution episode of October 30^th-31 ^stwas actually the lightest among the four episodes,with daily average Pm^2.5concentration of 154 μg/m^3.Model simulation analysis showed that regional transport contribution to Beijing＇s air pollution ranged between 42.36%-69.12%,and also that the formation of secondary inorganic and organic aerosols was significant.

关 键 词：重污染 成因 逆温 区域输送 

分 类 号：X51[环境科学与工程—环境工程]