北京地区大气颗粒物污染的风向因素研究

2005年9月～2006年9月在北京市北部、中部、南部3个点位采集了大气总悬浮颗粒物(TSP)样品,并采用电感耦合等离子体光谱、质谱技术测定了29种无机元素.基于大气浓度数据和气象观测资料,研究了925hPa时不同风向对北京市TSP浓度及Al、Fe、Ca、S、Se、Pb、Zn等特征元素空间分布及来源的影响.结果表明,TSP及Al、Fe等地壳来源元素在东北、西北、西南3种风向下,3点位的平均浓度变化不大,表现出明显的顺东北风递增的特征;Pb、Zn等冶炼排放元素的3点位平均浓度以西南风时为高,并表现出明显的顺西南风递减的特征.Pb、Zn等重金属元素主要来源于北京南部以远地区有色冶金企业排放的大气传输;而地壳元素主要来自北京本地排放源的贡献.

Impact of wind direction on atmospheric particulate matter concentrations in Beijing

TSP samples were collected at three sites in southern suburb, downtown and northern suburb of Beijing from September 2005 to September 2006. 29 elements were determined using ICP-AES and ICP-MS. Based on meteorological data as well as air concentrations, spatial distributions and sources of TSP and its characteristics elements such as Al, Fe, Ca、 S、 Se、 Pb、 Zn under different wind directions were investigated. The concentrations averaged over sites for TSP as well as Al, Fe varied slightly for three wind directions; and concentrations at 3 sites demonstrated stepwise increasing trends along with the northeastlies. On the other hand, concentrations for typical heavy metals emitted from non-ferrous industry such as Pb and Zn were substantially higher when southwestlies prevail; and concentrations at 3 sites demonstrated stepwise decline trends along with the southwestlies. Pb, Zn and some heavy metals were most likely of atmospheric transport contribution from non-ferrous industrial emission in the region to the south of southern suburb of Beijing; whereas Al, Fe and other crustal elements were mainly from local sources of Beijing.