吸湿性是大气颗粒物最重要的物理化学性质之一,直接影响着实际大气条件下气溶胶的粒径、形貌、成分、化学反应活性和光学性质,从而最终影响着气溶胶的环境与气候效应.现有的吸湿性测量技术大多需要假设颗粒物为球形,且灵敏度较低,无法准确测定非球形颗粒物或吸湿性较低颗粒物的吸湿性.蒸汽吸附分析仪通过测量颗粒物的质量随相对湿度的变化来研究其吸湿性,这种新方法不仅对颗粒物的形貌没有要求,而且具有卓越的灵敏度.本文首先介绍了这种气溶胶吸湿性测量新方法的工作原理和技术特点,然后重点介绍了这种新方法在大气科学、地球与行星科学、医用气溶胶等多个领域中的应用.最后,在简要总结蒸汽吸附分析仪在大气颗粒物吸湿性研究上的优越性和局限性的基础上,对未来可开展的吸湿性研究工作提出了一些设想.
As one of the most important physical and chemical properties of atmospheric particulate matter,hygroscopicity can directly affect the particle size,morphology,chemical composition,chemical reactivity,and optical properties of aerosol particles under ambient conditions,thereby ultimately having an impact on the environmental and climatic effects of aerosol particles.Most existing widely used hygroscopicity measurement techniques have low sensitivity and assume that the particles are spherical,making it difficult to accurately determine the hygroscopicity of non-spherical or low-hygroscopic particulate matter.Comparatively,vapor sorption analyzer studies the hygroscopicity of particles by measuring the mass change of particle samples as a function of relative humidity.This new method not only has no requirements for particle morphology,but also has excellent measurement sensitivity.In this paper,the working principle and technical characteristics of this new method for aerosol hygroscopic measurement are introduced firstly,and then the application of this new method in atmospheric science,earth and planetary science,medical aerosol particles,and other fields is described in detail.Finally,based on the brief summary of the advantages and limitations of the vapor sorption analyzer in the study of atmospheric particle hygroscopicity,some future research directions are discussed and prospected.