Unlocking the Mystery of Aerosol Phase Transitions Governed by Relative Humidity History Through an Advanced Outdoor Nephelometer System

Abstract This study introduces an innovative outdoor nephelometer system designed to monitor the dynamic hygroscopic behavior of aerosols in ambient air. Field measurements conducted in the Pearl River Delta region of China unveil significant roles of relative humidity (RH) swings on aerosol phase s...

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Bibliographic Details
Published in:Geophysical Research Letters
Main Authors: Hongqin Qiao, Ye Kuang, Fengling Yuan, Li Liu, Miaomiao Zhai, Hanbing Xu, Yu Zou, Tao Deng, Xuejiao Deng
Format: Article
Language:English
Published: Wiley 2024-03-01
Subjects:
nephelometer
hygroscopic growth
aerosol phase
light enhancement factor
relative humidity history
hygroscopicity
Online Access:https://doi.org/10.1029/2023GL107179
Description
Summary:Abstract This study introduces an innovative outdoor nephelometer system designed to monitor the dynamic hygroscopic behavior of aerosols in ambient air. Field measurements conducted in the Pearl River Delta region of China unveil significant roles of relative humidity (RH) swings on aerosol phase states. Highlighting the occurrence of aerosol crystallization in the afternoon followed by gradual deliquescence as RH increases, particularly when minimum afternoon RH drops below 35%, with no such behavior observed when it exceeds 40%. Emphasizing that aerosol phase states are shaped not only by RH and chemical composition but also by their RH history, illustrating that RH levels of 70% in the morning or evening may correspond to fully dissolved metastable or partially dissolved metastable states of ambient aerosols. These findings underscore the need to account for RH history when predicting aerosol phase states and have broader implications for comprehending aerosol behavior and its atmospheric impacts.
ISSN:0094-8276
1944-8007

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