Collaborative Research: Reactive Chlorine Cycling in Marine Air

点击翻译按钮获取中文摘要

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.