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Hygroscopic Properties of Saline Mineral Dust From Different Regions in China: Geographical Variations, Compositional Dependence, and Atmospheric Implications
Author(s) -
Tang Mingjin,
Zhang Huanhuan,
Gu Wenjun,
Gao Jie,
Jian Xing,
Shi Guoliang,
Zhu Bingqi,
Xie Luhua,
Guo Liya,
Gao Xiaoyan,
Wang Zhe,
Zhang Guohua,
Wang Xinming
Publication year - 2019
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
eISSN - 2169-8996
pISSN - 2169-897X
DOI - 10.1029/2019jd031128
Subject(s) - relative humidity , mineral dust , aerosol , mineral , particulates , chemistry , cloud condensation nuclei , humidity , environmental chemistry , chemical composition , mineralogy , atmospheric sciences , meteorology , geology , physics , organic chemistry
Saline mineral dust particles, emitted from saline topsoil in arid and semiarid regions, contribute significantly to tropospheric aerosol particles. However, hygroscopic properties of saline mineral dust particles, especially for those found in regions other than North America, are poorly understood. In this work we investigated hygroscopic properties of 13 saline mineral dust samples collected from different locations via measuring sample mass change at different relative humidity (RH; up to 90%), and measured their chemical and mineralogical compositions using ion chromatography and X‐ray diffraction. The mass growth factors at 90% RH, defined as the sample mass at 90% RH relative to that at <1% RH, were found to display large geographical variations, spanning from ~1.02 to 6.7, and the corresponding single hygroscopicity parameters ( κ ) were derived to be in the range of <0.01 to >1.0. The saline components (mainly Na + , Cl − , and SO 4 2− ) contained by saline mineral dust particles largely determined their hygroscopicity, and the predicted mass growth factors at 90% RH using an aerosol thermodynamic model (ISORROPIA‐II), agreed with measured values within 20% for most of samples examined, although larger discrepancies also occurred for three samples. Our results improve our understanding in hygroscopicity of saline mineral dust particles and thus their heterogeneous chemistry and ability to serve as cloud condensation nuclei to form cloud droplets.