Collaborative Research: A Halogen Oxidant Flow Reactor: Development and Use in Laboratory and Field Studies

该项目是三个机构之间的合作努力，旨在开发一种技术，用于研究大气中涉及氯和溴等卤素的化学反应。 最近，该项目的首席科学家开发了一种类似的技术，使用氧化流动反应器（OFR），用于研究涉及羟基自由基的大气反应，羟基自由基是大气中最活跃的氧化物质。 OFR的发展大大提高了科学家在实验室中研究和理解大气反应过程的能力。本研究的总体目标是开发在OFR中产生氯（Cl）和溴（Br）的方法，在具有潜在Cl/Br影响的源区部署原型卤素OFR沿着最先进的质谱技术，进行臭氧研究室和环境室（EC）的化学成分和生物和人为前体的氯氧化产生的产品产量的相互比较研究。这些研究将评估OFR进行实验室和现场研究调查Cl/Br引发的氧化老化processes.The努力的能力是基于调查以下问题：（1）什么是氧化挥发性有机化合物（OVOC）和二次有机气溶胶（SOA）的形成潜力的环境空气暴露于卤素原子在OFR？它如何作为卤素类型、综合氧化剂暴露和源区域的函数而变化？(2)通过VOC + Cl反应生成的实验室SOA的产率和化学成分是否与生成方法（OFR或EC）无关？(3)实验室和环境中OVOC/SOA的化学组成和产率在由Cl/Br引发时与羟基自由基氧化时相比如何？多氧化剂OFR方法是否对OVOC/SOA前体提供了额外的限制？该项目包括为本科生和研究生以及博士后研究员提供实验室培训。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

This project is a collaborative effort among three institutions to develop a technique for studying chemical reactions in the atmosphere that involve halogens, such as chlorine and bromine. Recently, the lead scientist on this project developed a similar technique, using an oxidation flow reactor (OFR), for the study of atmospheric reactions involving the hydroxyl radical, the most active oxidizing species in the atmosphere. The development of the OFR has advanced significantly the ability of scientists to study and understand atmospheric reaction processes in the laboratory.The overall goals of this research are to develop methods to generate chlorine (Cl) and bromine (Br) in OFRs, deploy a prototype halogen OFR along with state-of-the-art mass spectrometry techniques in source regions with potential Cl/Br influence, and conduct OFR and environmental chamber (EC) intercomparison studies of the chemical composition and yields of products generated from Cl oxidation of biogenic and anthropogenic precursors. These studies will evaluate the ability of OFRs to conduct laboratory and field studies investigating Cl/Br-initiated oxidative aging processes.The effort is based on investigating the following questions: (1) What is the oxygenated volatile organic compound (OVOC) and secondary organic aerosol (SOA) formation potential of ambient air exposed to halogen atoms in an OFR? How does it change as a function of halogen type, integrated oxidant exposure and source regions? (2) Is the yield and chemical composition of laboratory SOA generated by VOC + Cl reactions independent of the method used to generate it (OFR or EC)? (3) How does the chemical composition and yield of laboratory and ambient OVOC/SOA compare when initiated by Cl/Br versus hydroxyl radical oxidation? Does the multi-oxidant-OFR approach provide additional constraints on OVOC/SOA precursors?This project includes laboratory training for undergraduate and graduate students and a postdoctoral research fellow.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.