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

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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.