北京城区和远郊区大气气溶胶的相似性研究

文章通过对北京城区和远郊区采集的气溶胶样品物理化学性质的分析,考察了两地气溶胶性质的相似性。 样品于2001年9月7～16日,11月3～27日,2002年1月30日～2月6日和2003年1月28日～5月21日分别在北 京舞蹈学院(城区)和昌平昭陵(远郊区)进行采集。根据元素富集因子(EF)的分析,几大类元素的源相似,自然源和 人为源对其均有重要的贡献。当然,在两地的大气气溶胶浓度是不同的。秋季总悬浮颗粒物平均浓度城区为177.1 g/m3,远郊区为117.4g/m3。城区气溶胶细粒子Pm².5质量浓度冬季为153g/m3,秋季为124.3g/m3。城区和 远郊区的大气气溶胶中各类元素占所测元素的百分数相近。两地主要元素百分数序列均为(Fe,Ca,Al)>(K,Na, Mg,Cl)>(S,Sb,As)>(Br,Ba,V,Pb),前3项之和超过94%。城、远郊区大气气溶胶质量浓度和元素浓度的粒径分 布也很相似。用Andersen9级采样器采集的气溶胶质量浓度PM10占其总质量浓度PM(A总)的95%以上,Pm².1/ PM10>62%。可见,气溶胶中可吸入颗粒物占绝对优势,而可吸入颗粒物又以细粒子为主。细粒子中以人为污染元 素S,As,Pb,Br和Zn为主,其Pm².1/PM10>60%,最高可达90%。气溶胶细粒子Pm².5的污染是区域性的。在城 区北京舞蹈学院单点监测的Pm².5,一定程度上可反应出北京市区Pm².

ON THE SIMILARITY OF THE AEROSOL CHARACTERISTICS IN CITY AND SUBURB OF BEIJING

The similarity of physical and chemical characteristics of two group aerosol samples collected in the city and suburb of Beijing respectively have been investigated. The samples were collected in 4 different time periods, froM _Sept. 7 to 16, Nov. 3 to 27, 2001, Jan. 30 to Feb. 6, 2002, and Jan. 28 to May 21, 2003 at the Beijing Dancing College (BDC) in the city and at the Ming Tomb Zhao (MTZ), Changping County in the suburb. According to the enrichment factor analysis, some categories of aerosol sources for the city were similar to that for the suburb, suggesting that both of the contribution of human emission and that of natural factors were important at the two places. The TSP (total suspended particle) concentrations averaged in autumn, for example, were 177.1μg/m ³ and 117.4μg/m ³ at BDC and MTZ respectively. The aerosol mass concentrations of Pm².5 were 153μg/m ³ and 124.3μg/m ³ at BDC in winter and in autumn respectively. The proportions of every category of elements were similar to each other at both BDC and MTZ. The order of elemental groups in their concentration proportions to the total were (Fe, Ca, Al) > (K, Na, Mg, Cl) > (S, Sb, As) > (Br, Ba, V, Pb) at both BDC and MTZ, and the proportion of elemental concentration of the first 3 groups to the total was 94%. The aerosol size distributions for TSP and elements at BDC were similar to those at MTZ. For instance, the proportion of PM10 to the total PM was over 95% and Pm².1 / PM10>62%. The results indicate that the breathable particles in aerosols occupied the dominant position in the mass concentration, and the fine particles occupied the dominant position in the breathable particles. The fine particles consisted mainly of the elements S, As, Pb, Br, and Zn and their value Pm².1/PM10 > 60%, even reached at 90%. For the fine particle pollution, the distribution of Pm².5 observed at the spot BDC may be regional, and to a certain extent, cloud be the a representative of the city Beijing.