Aerosol hygroscopic behavior plays a central role in determining climate effects and environmental influence of atmospheric particulates. Water-soluble organic acids (WSOAs) constitute a significant fraction of organic aerosols. These organic acids have a complex impact on aerosol hygroscopicity due to their physical and chemical interactions with atmospheric inorganic salts. The mixing of WSOAs with inorganic salts exerts a multiple influence on the hygroscopic growth and phase behaviors of aerosol particles, largely depending on the composition ratio, acid properties, particle size and interactions between particle components. The WSOAs play a critical role in determining water uptake characteristics of aerosol particles, especially in the low and moderate RH ranges. The previous studies reveal the occurrence of aerosol chemistry related to chloride/nitrate/ammonium depletions in aerosol droplets containing WSOAs and inorganic salts. The potential influence of WSOAs on the atmospheric recycling of HCl/HNO₃/NH₃ due to the chloride/nitrate/ammonium depletion may contribute to the atmospheric budget of reactive gases. A fundamental understanding for the hygroscopic behavior and aerosol chemistry of inorganic–WSOA systems is essential for the accurate parameterization of aerosol behaviors in atmospheric models. However, there is still lack of a comprehensive understanding of the hygroscopicity and related aerosol chemistry of internally mixed inorganic–WSOA systems. The present review comprehensively summarizes the impacts of WSOAs on hygroscopicity and phase changes of atmospherically relevant inorganic salts in aerosol particles especially under subsaturated conditions, and overviews the recent advances on aerosol chemistry related to the hygroscopic process for the internally mixed inorganic–WSOA aerosols.

气溶胶吸湿行为在确定大气颗粒物的气候影响和环境影响方面发挥着核心作用。水溶性有机酸（WSOA）占有机气溶胶的很大一部分。这些有机酸由于与大气无机盐的物理和化学相互作用而对气溶胶吸湿性产生复杂的影响。 WSOA与无机盐的混合对气溶胶颗粒的吸湿生长和相行为产生多重影响，很大程度上取决于组成比、酸性质、颗粒尺寸和颗粒组分之间的相互作用。 WSOA 在确定气溶胶颗粒的吸水特性方面发挥着关键作用，特别是在低和中等相对湿度范围内。先前的研究揭示了与含有 WSOA 和无机盐的气溶胶液滴中氯化物/硝酸盐/铵消耗相关的气溶胶化学的发生。由于氯化物/硝酸盐/铵的消耗，WSOA 对 HCl/HNO ₃ /NH ₃大气循环的潜在影响可能会增加反应气体的大气预算。对无机-WSOA系统的吸湿行为和气溶胶化学的基本了解对于大气模型中气溶胶行为的精确参数化至关重要。然而，对于内部混合无机-WSOA系统的吸湿性和相关气溶胶化学仍然缺乏全面的了解。 本文全面总结了WSOA对气溶胶颗粒中大气相关无机盐吸湿性和相变的影响，特别是在过饱和条件下，并概述了与内部混合无机-WSOA气溶胶吸湿过程相关的气溶胶化学的最新进展。