A hygroscopic tandem differential mobility analyzer(HTDMA) is designed and constructed.The hygroscopicity of submicron particles in Shouxian is studied in July 2016,and the HTDMA is applied to measure the hygroscopic properties for particles with dry diameter between 50~250 nm.The statistical results show that,the average growth factor(FG) of the aerosol presents a distinct bimodal distribution.For the less-hygroscopic component,the FG is 1.07,and for more-hygroscopic compound,the FG is between 1.373~1.560 and positively correlated with the particle size.After humidification,the average spectral distribution of the peak value of the local polydisperse aerosol shows a slight increase with bimodal distribution,indicating the hygroscopic ability of different diameter particles are different,and the proportion of less-and more-hygroscopic component are also different.The difference between the spectral distribution of aerosols at different time(day and night) reflects the different source of aerosols.The less-hygroscopic components mainly come from local emissions and the more-hygroscopic components mainly come from distance transport.%设计建立了一套适用于外场观测研究的吸湿性串联差分电迁移率分析仪(HTDMA),并利用该套仪器于2016年7月在安徽省寿县对50~250 nm大气气溶胶粒子在高相对湿度下的吸湿特性进行了观测.结果表明,不同粒径单分散气溶胶和多分散气溶胶的吸湿增长因子多呈现双峰分布,弱吸湿增长因子约1.07,强吸湿增长因子随粒径50~250 nm变化从1.37增大到1.56.当地多分散气溶胶吸湿增长之后的平均谱分布较未吸湿的平均谱分布出现峰值向右偏移稍微增大和双峰分布的现象,说明当地大气中不同粒径颗粒物的吸湿能力以及强弱吸湿组分比例不一样;不同时间段(白天和夜晚)多分散气溶胶加湿与否的平均谱分布差异反映了细粒子颗粒物主要来源于本地排放,强吸湿性大粒径颗粒物主要来自于远距离传输影响.
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