摘要
利用2005~2010年北京上甸子本底站的PM2.5浓度、气溶胶散射系数(σsp)的连续观测资料,结合后向轨迹分析方法,探讨了不同季节、不同气团传输路径对本底地区气溶胶光学特性的影响.结果表明,污染物水平不仅与气团来向有关,也与气团的运动状态有关.偏南气团路径下的PM2.5浓度和σsp整体高于偏北气团路径,同时运动速度较慢、高度较低的气团路径多对应较高的PM2.5浓度和σsp.春、夏、秋季来自华北平原地区以及冬季来自华北区域北部的慢速、低气团对上甸子的污染水平有重要贡献.沙尘气溶胶多出现在春季,平均气溶胶质量散射效率(αsp)为0.78 m2·g-1.四季平均人为污染气溶胶的αsp为4.00 m2·g-1,其中冬季最高,春季最低.对于人为污染气溶胶来说,春、夏、秋三季的西北偏西路径、偏南路径以及偏北路径中速度较慢的轨迹组均具有较高的αsp(>4.0 m2·g-1),表明这些气团路径受人为排放活动影响较大,而冬季各路径的αsp均较高,说明冬季区域内人为排放的影响比较一致.春、夏、秋三季中其他偏北的气团路径主要受到人为污染与沙尘气溶胶的共同影响.
The impact of transport pathways on aerosol properties at Shangdianzi( SDZ) background station was analyzed using the back trajectory analysis method with the observation of PM2. 5concentration and aerosol scattering coefficients( σsp) during 2005-2010.The results showed that the pollutant level at SDZ was influenced by both the direction and motion state of air masses. The southerly transport pathways of air masses had higher PM2. 5concentration and σspthan those of northerly pathways. The air masses with lower moving speed and altitude generally corresponded to higher PM2. 5concentration and σsp. Air masses originated from the North China Plain in spring,summer and autumn,and air masses from the north of North China region in winter had a significant contribution to PM2. 5concentration and σspat SDZ. Dust aerosol appeared frequently in spring,and the mean scattering efficiency( αsp) was 0. 78m2·g- 1. The mean αspof anthropogenic aerosol of four seasons was 4. 00 m2·g- 1with the highest value in winter and the lowest in spring. The west-northwest,southerly pathways,and the northerly pathways with low moving speed in spring,summer and autumn correspond to higher αsp( > 4. 0 m2·g- 1). This indicated that these pathways were affected by the emissions form human activities.However,the αspin winter kept at a high level among all pathways,which suggested that the emission effect was relatively uniform in surrounding regions in winter. The other northerly pathways in spring,summer and autumn were affected by anthropogenic pollutants mixed with dust.
出处
《环境科学》
EI
CAS
CSCD
北大核心
2015年第2期379-387,共9页
Environmental Science
基金
国家自然科学基金项目(41305130
41175014)
城市气象科学研究基金项目(UMRF201206)
北京市科委绿色通道项目(Z131100005613024)
北京市自然科学基金项目(8122022)
关键词
传输路径
PM2.5
散射系数
散射效率
上甸子本底站
transport pathway
PM2.5
scattering coefficients
scattering efficiency
Shangdianzi background station
