北京市东北城区冬季大气细粒子与相关气体污染特征

利用VAPS通用型大气污染物采样仪与DX-600型离子色谱仪于2008年11月及2009年1月进行了北京市东北城区大气细粒子(PM2.5) 可溶性离子组分和相关气体组分的同时监测与分析.结果表明,在采样期间,北京PM2.5质量浓度随时间呈“3峰”的变化,在“3个峰段”期,随采样时间的推进,PM2.5质量浓度增高;与北京市以往监测结果相比,北京市PM2.5中几种主要水溶性无机离子的污染水平呈现下降的趋势;PM2.5呈弱酸性,对大气环境酸化和酸性湿沉降的形成具有一定的促进作用;PM2.5中NH4+主要以硫酸盐、硝酸盐及氯盐的形式存在;PM2.5中SO42-、NO3-的质量浓度变化趋势分别与环境空气中SO2、NO2的质量浓度变化趋势相似,PM2.5中SO42-和NO3-分别主要由SO2、NO2转化而来,且NO2二次转化率低于SO2的二次转化率.

Pollution characteristics of the atmospheric fine particles and related gaseous pollutants in the northeastern urban area of Beijing in winter season

Simultaneous measurements of water-soluble inorganic ions in PM2.5 and related gaseous pollutants in November 2008 and in January 2009 were made by using an versatile air pollutants sampler (URG-3000K) and a DX-600 ion chromatography in the northeastern urban area of Beijing. The mass concentrations of PM2.5 showed the “3 peaks” changing style, and in the “3 peaks” period, the mass concentrations of PM2.5 became higher with the sampling time passed by. The pollution level of the major water-soluble inorganic ions in PM2.5 decreased compared with the past monitoring results in Beijing and other big cities. PM2.5 had weak acidity, which would promote the acidification of the atmosphere environment and the forming of acidic precipitation. NH4+ in PM2.5 existed mainly in the form of sulfate, nitrate and chloride. The mass concentrations of SO42- and NO3- in PM2.5 had the similar variation trend with those of SO2 and NO2, respectively. SO42- and NO3- in PM2.5 were mainly transformed from SO2 and NO2, respectively, and the second conversion rate of NO2 was lower than that of SO2.