Application of physisorption analyzer in measuring the hygroscopicity of atmospheric aerosols

The hygroscopicity represents a vital physicochemical attribute of aerosols, governing their phase state, acidity, viscosity, chemical reactivity, and other properties, thereby influencing various atmospheric processes, including visibility, radiative forcing, and the formation of cloud condensation nuclei. In this study, the hygroscopicity of common inorganic aerosol particles (NH4)2SO4 and NaCl in the atmosphere was determined using a physisorption analyzer under 298 K conditions, exploring its application prospects in measuring atmospheric aerosol hygroscopicity. By measuring the adsorption of particles to water vapor at different relative humidity (RH) levels, the variation curve of the aerosol particle hygroscopic mass growth factor (MGF) and deliquescence relative humidity (DRH) were obtained. Comparisons with vacuum FTIR methods, the Extended Aerosol Inorganic Model (EAIM), and relevant literature data showed good agreement. This research paves the way for future applications of physisorption analyzer in the study of atmospheric aerosols.