Effect of mixing structure on the hygroscopic behavior of ultrafine ammonium sulfate particles mixed with succinic acid and levoglucosan

详细信息    查看全文

• 作者：Shila Maskey ; Ka Yan Chong ; Gibaek Kim ; Jae-Seok Kim ; Arshad Ali ; Kihong Park ; ^{kpark@gist.ac.kr" class="auth_mail}
• 关键词：AIM ; aerosol inorganic model ; CPC ; condensation particle counter ; DMA ; differential mobility analyzer ; DRH ; deliquescence relative humidity ; GF ; growth factor ; HTDMA ; hygroscopicity tandem differential mobility analyzer ; RH ; relative humidity ; SMPS ; scanning mobility particle sizer
• 刊名：Particuology
• 出版年：April, 2014
• 年：2014
• 卷：13
• 期：Complete
• 页码：27-34
• 全文大小：1631 K

文摘

Understanding the interactions between water and atmospheric aerosols is critical for estimating their impact on the radiation budget and cloud formation. The hygroscopic behavior of ultrafine (<100 nm) ammonium sulfate particles internally mixed with either succinic acid (slightly soluble) or levoglucosan (soluble) in different mixing structures (core-shell vs. well-mixed) were measured using a hygroscopicity tandem differential mobility analyzer (HTDMA). During the hydration process (6-92% relative humidity (RH)), the size of core-shell particles (ammonium sulfate and succinic acid) remained unchanged until a slow increase in particle size occurred at 79% RH; however, an abrupt increase in size (i.e., a clear deliquescence) was observed at 鈭?2% RH for well-mixed particles with a similar volume fraction to the core-shell particles (80:20 by volume). This increase might occur because the shell hindered the complete dissolution of the core-shell particles below 92% RH. The onset RH value was lower for the ammonium sulfate/levoglucosan core-shell particles than the ammonium sulfate/succinic acid core-shell particles due to levoglucosan's higher solubility relative to succinic acid. The growth factor (GF) of the core-shell particles was lower than that of the well-mixed particles, while the GF of the ammonium sulfate/levoglucosan particles was higher than that of ammonium sulfate/succinic acid particles with the same volume fractions. As the volume fraction of the organic species increased, the GF decreased. The data suggest that the mixing structure is also important when determining hygroscopic behavior of the mixed particles.