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为研究京津冀地区冬、夏两季大气颗粒物质量浓度与水溶性离子组成特征，于2013年2月、7月对北京、天津、石家庄及4个国家大气背景点进行了PM2．5及PM10的采样，分析了质量浓度及9种水溶性离子，结果表明：（1）京津冀地区颗粒物污染冬季重于夏季，冬季污染水平石家庄＞天津＞北京，夏季污染天津、北京＞石家庄，区域内PM2．5与PM10之间有很好的相关性，相关系数r冬季为0．8796，夏季为0．8424，说明整个区域颗粒物污染有较为相近的来源，大气颗粒物污染表现出区域性特征；（2）京津冀地区PM2．5及PM10中的9种水溶性离子浓度规律为NO－3、SO2－4、NH＋4＞Cl－、Ca2＋＞K＋、Na＋＞F－、Mg2＋．该地区水溶性离子污染冬季最重为石家庄，夏季则为北京；（3）在京津冀地区二次离子NO－3、SO2－4、NH＋4是主要的污染离子，3种离子质量浓度总和在PM2．5、PM10中冬季分别占48．9％、27．8％，夏季分别占58．7％、48．5％．二次离子主要集中在PM2．5中，其对细离子浓度的升高起到直接作用，且二次离子的构成关系也在发生变化．整个区域向硝酸型污染转变，二次离子的季节分布也呈现区域特征，冬季NO－3离子质量浓度比重最大．夏季则为SO2－4；（4）粒径越小富集水溶性离子的能力越强，在PM1中分布了50％以上的水溶性离子，73．9％—94．8％的水溶性离子分布在PM2．5中．

To investigate particle pollution in BTH ( Beijing Tianjin and Shijiazhuang) area, PM2.5 and PM10 samples were collected at three urban sites ( Beijing, Tianjin and Shijiazhuang) and four National Atmospheric Back ground sites in the winter and summer of 2013. The mass concentrations were measured and inorganic water?soluble ions were analyzed. The results show that the mass concentrations were quite high in winter, and the Shijiazhuang site had the highest concentrations. However, in summer, the particle concentration was higher in Beijing and Tianjin. The correlations of PM2.5 and PM10were strong in all the sites of the BTH area, and the correlation coefficient (r) was 0.8796 in winter and 0. 8424 in summer, suggesting that the particulate pollution sources of the whole regional were similar. The concentrations of water?soluble ion concentrations showed similar characteristics in both summer and winter, which was NO-3 , SO2-4 , NH+4>Cl-, Ca2+>K+, Na+>F-, Mg2+.Shijiazhuangwasthe most polluted site in winter, and while in summer it was Beijing. The secondary ions were the most important compounds in the particles of this area, because they accounted for a large fraction of PM2.5 and PM10. SNA (total concentration of sulphate, nitrite and ammonium) accounted for 48.9%, 27.8% of PM2.5 and PM10 in winter, respectively and 58.7%, 48?5% in summer. Secondary compounds were mainly concentrated in PM2.5, suggesting that the secondary ions play a more important role in fine particles. Compared with the historical data, the contribution of NO-3 was higher than before, but the contribution of SO2-4 was lower . The enrichment ability of soluble ions is stronger in smaller particles . The contribution of the total water soluble ions to PM1was more than 50%, and 73.9%—94.8% in PM2.5.