基于密度和粒径实测校正的单颗粒气溶胶质谱定量方法研究

Regional haze pollution is one of the major environmental problems in China. Although aerosol time-of-flight mass spectrometer (ATOFMS) plays an important role in interpreting the formation mechanism of haze pollution, the size-dependent transmission efficiency limits the ATOFMS application in particle quantitative and in source apportionment. The present project proposed to scale the ATOFMS concentration using the number and size distribution data obtained from synchronous measurement. And the size-resolved particle density is also measured to improve the accuracy of mass concentration quantification from ATOFMS analysis. Compared with collocated chemical composition measurements, the quantification method is further improved by excluding some extremely low transmission particles. By applying ATOFMS quantification procedures, our recognition on physical and chemical properties of atmospheric particulates would be promoted. The application of ATOFMS will favor the understand of the chemical resolved composition of particles, and will also provide new sight for rapid source apportionment of particles.

区域性大气灰霾污染是我国当前面临的重大环境问题之一。单颗粒气溶胶飞行时间质谱(ATOFMS)在灰霾形成机制研究中发挥着重要作用，但由于粒径选择问题严重限制了ATOFMS在颗粒物定量分析及来源解析中的应用。本研究拟通过同步实测颗粒物粒径分布，对ATOFMS的质量浓度进行定量；同时通过同步实测颗粒物密度分布，进一步提高ATOFMS定量分析的准确性；通过与全样品分析数据的对比验证，对一些检出效率极低的组分的定量方案进行优化。通过对ATOFMS测量结果进行定量表征，可以获得更为真实的反应大气颗粒物理化性质的定量化数据信息，为深入认识颗粒物的粒径分布等理化特征和开展颗粒物来源快速解析工作提供新思路。

区域性大气灰霾污染是我国当前面临的重大环境问题之一。单颗粒气溶胶飞行时间质谱(ATOFMS)在灰霾形成机制研究中发挥着重要作用，但由于粒径选择问题严重限制了ATOFMS在颗粒物定量分析及来源解析中的应用。本研究采用SMPS和APS实测获得颗粒物的真实粒径分布，经管路损失校正后对ATOFMS的数浓度进行定量，并基于球形例子假设实现对质量浓度的定量；同时通过颗粒物密度的实测推算，进一步提高ATOFMS定量分析的准确性；通过与全样品在线分析数据的对比验证，发现PM质量浓度、硝酸盐和有机物的定量结果准确度较高，其次为元素碳、铵盐和硫酸盐，而氯盐的定量结果相对较差。经过密度和粒径分布实测校正后，ATOFMS测量颗粒物及主要组分的书浓度粒径分布集中在100nm左右，而质量浓度集中在300~400nm左右，与AMS获得的质量浓度分布特征有较好的可比性。通过校正，ATOFMS获得的粒径分布特征更能反映真实的大气颗粒物理化性质。