Atmospheric peroxides in a polluted subtropical environment: seasonal variation, sources and sinks, and importance of heterogeneous processes.
Atmospheric peroxides in a polluted subtropical environment: seasonal variation, sources and sinks, and importance of heterogeneous processes.
复制标题
DOI：
10.1021/es403229x
复制
发表时间：
2014-01
影响因子：
11.4
通讯作者：
Jia Guo;A. Tilgner;Chungpong Yeung;Zhe Wang;P. Louie;C. Luk;Zhengning Xu;Chao Yuan;Yuan Gao-Yua
中科院分区：
文献类型：
--
作者：
Jia Guo;A. Tilgner;Chungpong Yeung;Zhe Wang;P. Louie;C. Luk;Zhengning Xu;Chao Yuan;Yuan Gao-Yua
过氧化氢(H_2O_2)和有机过氧化氢在大气化学中起着重要的作用，但对它们的丰度、来源和来自非均相过程的汇的了解仍然不完整。在此，我们报告了2011-2012年在香港郊区的一个站点和一个背景站点的四季的测量结果。有机过氧化氢的含量比过氧化氢更丰富，这与以往的大多数观察结果形成了鲜明对比。具有多相化学机制的模型计算表明，非均相过程(主要是过渡金属离子[TMI]-HOX反应)对H_2O_2的预算有重要贡献，分别约占总产率和损失率的三分之一和一半以上。相比之下，它们对有机过氧化物的贡献要小得多。这些非均相反应对过氧化氢的快速去除解释了观察到的高有机过氧化物组分。敏感性分析表明，非均相过程的作用依赖于气溶胶中可溶金属的丰度，在低金属浓度时起到净H_2O_2源的作用，但在高金属负荷时起到净汇作用。这项研究的结果表明，在检查气相过氧化氢的化学收支时，需要考虑气溶胶水相中的化学过程。
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 2011-2012 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.