Collaborative Research: A Nitrate Radical Oxidation Flow Reactor: Development and Use in Laboratory and Field Studies

这个项目是一个合作项目，旨在开发一种新的工具来研究氮在夜间大气化学中的作用。将建造一个现场可部署的氧化流反应器（OFR），以提供对硝酸盐自由基（NO3）引发的大气氧化老化过程的新见解。实验将在环境室和ofr中进行，以区分羟基（OH）和硝酸盐自由基对氧化性挥发性有机化合物（OVOCs）和二次有机气溶胶（SOA）形成的相对贡献。这些物种可以对天气、气候和人类健康产生广泛的影响。这项工作解决了以下问题：(1)ofr在多大程度上可以从VOC + NO3反应中重现地生成OVOCs和SOA ？(2)连续多天的氧化老化过程是否形成独特的氧化产物，可用于在大气中追踪这些过程？(3) OFR中暴露于NO3和OH自由基的环境空气的OVOC和SOA形成电位是什么，以及它如何作为综合氧化剂暴露和源区域的函数变化？(4)环境空气的NO3- ofr扰动是否能够更清晰地描述夜间NO3和O3的化学性质，特别是在识别不含氮的NO3氧化产物方面？该项目支持几名研究生和一名早期职业研究员。该奖项反映了美国国家科学基金会的法定使命，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 to develop a new tool to study of the role of nitrogen in nighttime chemistry in the atmosphere. A field-deployable Oxidation Flow Reactor (OFR) will be built to provide new insights into nitrate radical (NO3)-initiated atmospheric oxidative aging processes. Experiments will be conducted in both environmental chambers and OFRs to distinguish the relative contributions of hydroxyl (OH) and nitrate radicals to the formation of oxidized volatile organic compounds (OVOCs) and secondary organic aerosol (SOA). These species can have widespread impacts on weather, climate, and human health.This effort addresses the following questions: (1) To what extent can OFRs reproducibly generate OVOCs and SOA from VOC + NO3 reactions? (2) Are unique oxidation products formed from sequential multi-day oxidative aging processes that can be used to trace these processes in the atmosphere? (3) What is the OVOC and SOA formation potential of ambient air exposed to NO3 versus OH radicals in an OFR, and how does it change as a function of integrated oxidant exposure and source region? (4) Can NO3-OFR perturbations of ambient air enable clearer delineation between nighttime NO3 and O3 chemistry, especially with respect to identifying non-nitrogen-containing NO3 oxidation products?This project supports several graduate students and an early career researcher.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.