沙尘期间大气颗粒PM_(10)与PM_(2.5)化学组分的浓度变化及来源研究

Concentration Variation of Airborn Particles PM_(10) and PM_(2.5) Chemical Composition and Their Sources During Dust Events

于2006年3月—4月北京沙尘发生期间,监测了沙尘与非沙尘期间悬浮颗粒PM10和PM2.5质量浓度,分析了样品中无机水溶性离子和金属元素。结果显示:沙尘天气导致PM10和PM2.5质量浓度上升,粗颗粒物质量浓度明显上升,细颗粒物受到的影响相对较小。SO42-、NO3-和NH4+为PM10与PM2.5主要水溶性离子。沙尘与非沙尘期间SO42-、NO3-和NH4+浓度变化表现出不稳定性,可能与沙尘的强度和持续时间、来源有关,沙尘下来自于土壤源Ca2+和Mg2+浓度都显然提高。沙尘期间Sc、Ti、V、Cr、Mn、Co、Ni、Rb和Cs金属元素浓度高于非沙尘期间浓度,并且富集因子系数都小于10,说明主要来自于自然源,而Zn、Se、Cd、Pb和Bi这5种元素浓度随沙尘的侵入并没增加其含量,反而使浓度有所下降,富集因子和富集程度对比表明这些元素主要来自于当地污染源。

The suspended particulate matter PM10 and PM2.5 were collected during dust and non-dust periods in Beijing during March and April, 2006.The water-soluble inorganic ion species and 16 kinds of metal elements of PM10 and PM2.5 were detected. The mass concentrations of PM10 and PM2.5 increased during dust events comparing with non-dust, and the coarse particles increased during dust and the fine particles were affected but not so serious. SO4^2＋,NO3^- and NH4^＋ were the major water-soluble inorganic ion in the PM10 and PM2.5 The variety of SO4^2＋,NO3^- and NH4^＋ during dust and non-dust was not stable, which were affected by the extent and duration and the sources of dust. The concentrations of Ca^2＋ and Mg^2＋ from soil source increased during the dust. The concentrations of Sc, Ti, V, Cr, Mn, Co, Ni, Rb and Cs were higher in dust than the concentrations in non-dust and the values of enrichment factor were lower than 10, which indicated that they were from soil source. The concentration of Zn, Se, Cd, Pb and Bi decreased with the increasing of dnst and the values of Zn, Se, Cd, Pb and Bi enrichment Tactor were more than 10, which indicated that Zn, Se, Cd, Pb and Bi were from the native sources.