Collaborative Research: Reactive Chlorine Cycling in Marine Air

本研究旨在为海洋空气中活性氯的研究奠定基础。 活性氯化合物有可能改变大气中许多气候活性气体的寿命和反应途径。 由于缺乏对氯原子前体和反应产物的现场观测，对对流层氯化学的了解受到限制。 长期研究目标是评估（1）海洋空气中氯原子的水平和控制它们的光化学过程，（2）氯化学对甲烷和其他气候活性气体的影响，以及（3）人为污染物对大气氯反应性的影响。 然而，实现这一目标需要发展重要的分析能力。 因此，该项目的直接目标是开发和评估用于测量海洋空气中活性氯化合物水平的分析技术和仪器。 这项工作将通过提高我们对对流层氯反应性，特别是对甲烷的反应性以及人类对这种反应性的影响的理解，产生社会影响。 该项目还将支持欧文市加州大学一名研究生的教育。该项目涉及用于测量反应性氯循环中关键化合物（Cl2、BrCl、HOCl、ClO、HCl和ClONO2）以及辅助测量（HOx、NO2）的仪器的开发和现场测试。 这些测量将提供Cl原子水平的估计。 预计这项研究将最终导致对百慕大岛的清洁海洋空气和受北美污染物外流影响的空气进行实地观测。 最终目标是开发和验证模型，可用于定量评估海洋上的活性氯循环对甲烷和其他碳氢化合物寿命的影响。

This purpose of this research is to lay the fundamental analytical groundwork for the study of reactive chlorine in marine air. Reactive chlorine compounds have the potential to alter the lifetime and reaction pathways of many climate-active gases in the atmosphere. Understanding of tropospheric chlorine chemistry is limited by a lack of in situ observations of chlorine atom precursors and reaction products. The long-term research goal is to assess (1) the levels of Cl atoms in marine air and the photochemical processes controlling them, (2) the impact of chlorine chemistry on methane and other climate-active gases, and (3) the influence of anthropogenic pollutants on atmospheric Cl reactivity. However, achieving that goal requires development of important analytical capability. Accordingly, the immediate objective of this project is to develop and evaluate analytical techniques and instrumentation for measuring the levels of reactive Cl compounds in marine air. This work will have societal impact by improving our understanding of tropospheric chlorine reactivity, particularly towards methane, and human impact on that reactivity. It will also support the education of a graduate student at the University of California, Irvine.This project involves the development and field testing of instrumentation for measuring key compounds in reactive Cl cycling (Cl2, BrCl, HOCl, ClO, HCl, and ClONO2) as well as ancillary measurements (HOx, NO2). These measurements will provide an estimate of Cl atom levels. It is expected that study will eventually lead field observations on the island of Bermuda in both clean marine air and in air impacted by North American outflow of pollutants. The ultimate goal is to develop and validate models that can be used to quantitatively assess the impact of reactive Cl cycling over the oceans on the lifetime of methane and other hydrocarbons.