利用离子色谱技术对北京PM10和PM2.5中的水溶性阴离子(F^-,Cl^-,NO3^-和SO4^2-)进行了分析测定,并讨论了它们的分布、浓度变化和来源.F^-,Cl^-,NO3^-和SO4^2-离子的总质量分别占PM10和PM2.5总量的18.2%和24.2%,是大气颗粒物的重要组分.其中F^-主要存在于PM10的粗颗粒中,而Cl^-,NO3^-和SO4^2-则主要在细颗粒中富集.PM10和PM2.5中Cl^-在总氯中所占的比例分别达到了49.5%和40.3%,并与总氯具有非常好的相关性.氯在大气中明显富集,其主要的人为来源为煤的燃烧.SO4^2-和NO3^-具有比较好的相关性,其浓度在7月份最高,9、10月较低,进入冬季采暖期之后浓度升高.在PM10和PM2.5中NO3^-与SO4^2-的质量之比分别在0.1~0.6和0.1~0.5之间,说明燃煤对它们的贡献要大于汽车尾气.
Anionic species (F^- , Cl^- , NO3^- 和 SO4^2- ) of PM10 and PM2.5 in Beijing aerosol were determined by Ion Chromatography (IC), and their distribution concentration variation and sources were discussed. The results showed that the total masses of these four anions accounted for 18.2 % and 24.2 % of the total mass of PM10 and PM2.5, respectively. F- was mainly found in the coarse particles, however, Cl^- , NO3^ - and SO4^2- mainly existed in the fine particles. Relatively good correlations were found between the concentrations of Cl^- and total Cl in both PM10 and PM2.5, and the ratios of Cl^-/total C1 (mass) were about 49.5% (PM10) and 40.3% (PM2.5). Cl was enriched in the atmosphere, and its main anthropogenic source was coal burning. Good correlations were found between NO3^- and SO4^2- in both PM10 and PM2.5. The highest concentration of NO3^- and SO4^2- were found in July and relatively high concentration were also found in winter. The ratios of NO3 - / SO42- in PM10 and PM2.5 were between 0.1 ~ 0.6 and 0.1 - 0.5, respectively, which indicated that the main contribution of NO3^- and SO4^2- was coal burning, rather than mobile source.