Atmospheric Peroxides in a Polluted Subtropical Environment: Seasonal Variation, Sources and Sinks, and Importance of Heterogeneous Processes

详细信息    查看全文

• 作者：Jia Guo ; Andreas Tilgner ; Chungpong Yeung ; Zhe Wang ; Peter K. K. Louie ; Connie W. Y. Luk ; Zheng Xu ; Chao Yuan ; Yuan Gao ; Steven Poon ; Hartmut Herrmann ; Shuncheng Lee ; Ka Se Lam ; Tao Wang
• 刊名：Environmental Science & Technology
• 出版年：2014
• 出版时间：February 4, 2014
• 年：2014
• 卷：48
• 期：3
• 页码：1443-1450
• 全文大小：556K
• ISSN：1520-5851

文摘

Hydrogen peroxide (H₂O₂) and organic peroxides play an important role in atmospheric chemistry, but knowledge of their abundances, sources, and sinks from heterogeneous processes remains incomplete. Here we report the measurement results obtained in four seasons during 2011鈥?012 at a suburban site and a background site in Hong Kong. Organic peroxides were found to be more abundant than H₂O₂, which is in contrast to most previous observations. Model calculations with a multiphase chemical mechanism suggest important contributions from heterogeneous processes (primarily transition metal ion [TMI]-HOx reactions) to the H₂O₂ budget, accounting for about one-third and more than half of total production rate and loss rate, respectively. In comparison, they contribute much less to organic peroxides. The fast removal of H₂O₂ by these heterogeneous reactions explains the observed high organic peroxide fractions. Sensitivity analysis reveals that the role of heterogeneous processes depends on the abundance of soluble metals in aerosol, serving as a net H₂O₂ source at low metal concentrations, but as a net sink with high metal loading. The findings of this study suggest the need to consider the chemical processes in the aerosol aqueous phase when examining the chemical budget of gas-phase H₂O₂.