Tropospheric Aqueous-Phase OH Oxidation Chemistry: Current Understanding, Uptake of Highly Oxidized Organics and Its Effects
Tropospheric Aqueous-Phase OH Oxidation Chemistry: Current Understanding, Uptake of Highly Oxidized Organics and Its Effects
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DOI：
10.1021/bk-2018-1299.ch004
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发表时间：
2018
期刊：
影响因子：
--
通讯作者：
A. Tilgner;H. Herrmann
中科院分区：
文献类型：
--
作者：
A. Tilgner;H. Herrmann
对流层气相的氧化收支是相对公知的。然而，对流层水相中存在的重要氧化剂（如OH）的浓度和周转率相当不确定，这是由于所涉及的相关多相化学相互作用的复杂性较高。本章概述了（一）目前的水相OH氧化预算的理解，（二）最近的进展，重点是在该领域的吸收高度氧化的有机物以及它们对氧化能力的影响，在水性气溶胶，和（iii）未来的研究目标。详细地说，第一部分介绍了对流层水相内光化学OH汇和源的概述，重点是模拟和测量的OH原位形成率。它还讨论了目前模型和测量之间的差异，以及最后，两者的局限性。在这一部分中，使用CAPRAM模型模拟。他们证明，利用更详细的有机化学导致大幅降低水相OH浓度，更紧密地对齐建模和测量OH浓度。在第二部分中，总结了当前最先进的知识的作用和命运的有机过氧化物，不稳定的氢过氧化物，和其他有机过氧物种作为潜在的OH源。此外，最近的结果，利用CAPRAM的模型案例研究，允许检查的吸收和化学高度氧化的有机物从气相及其影响。案例研究表明，不稳定的氢过氧化物的吸收和随后的分解可能会导致平均增加19%的水OH汇和源率。最后，给出了一个简短的观点，包括概述了目前的差距，在水溶性气溶胶的氧化预算的知识，以及未来的实验室，现场和模型调查的研究目标。
The oxidation budget of the tropospheric gas phase is relatively well known. However, the concentrations and turnover rates of important oxidants such as OH that are present in the tropospheric aqueous phase are considerably more uncertain, as a result of the higher complexity of associated multiphase chemical interactions involved. This chapter outlines (i) the current understanding of the aqueous-phase OH oxidation budget, (ii) recent progress within the field with a focus on the uptake of highly oxidized organics as well as their effects on the oxidation capacity in aqueous aerosols, and (iii) future research objectives. In detail, the first part presents an overview on photochemical OH sinks and sources within the tropospheric aqueous phase, focusing on modelled and measured in-situ formation rates of OH. It also discusses current discrepancies between models and measurements as well as, finally, the limitations of both. In this part, model simulations using CAPRAM are presented. They demonstrate that utilizing a more detailed organic chemistry leads to substantially lowered aqueous-phase OH concentrations, more closely aligning modelled and measured OH concentrations. In the second part, a summary of current state-of-the-art knowledge on the role and fate of organic peroxides, labile hydroperoxides, and other organic peroxy species as potential OH sources is given. Furthermore, recent results of a model case study utilizing CAPRAM are presented, allowing an examination of the uptake and chemistry of highly oxidized organics from the gas phase and its effects. The case study demonstrates that the uptake and subsequent decomposition of labile hydroperoxides may lead to a mean increase of 19% of the aqueous OH sink and source rates. Finally, a brief perspective is given, including an outline of current gaps within the knowledge on the oxidation budget in aqueous aerosols as well as research objectives for future laboratory, field and model investigations.