Characterization of Oxygenated Volatile Organic Compounds and Secondary Organic Aerosol Generated from the Oxidation of Biogenic and Biomass Burning Precursors by Nitrate Radicals in an Oxidation Flow Reactor
Andrew Lambe, CHASE GLENN, Bin Bai, Anomitra De, David Pando, Nga Lee Ng, Drew Gentner, Pengfei Liu, Aerodyne Research, Inc.
Abstract Number: 128
Working Group: Aerosol Chemistry
Abstract
The importance of nitrate radicals (NO3) as a nighttime atmospheric oxidant is well established. For decades, laboratory studies investigating gas-phase NO3 chemistry have utilized the same NO2 + O3 reactions and/or N2O5 thermal decomposition to produce NO3 as it occurs in the atmosphere and accommodated the inherent limitations associated with N2O5, namely, that it must be generated and stored under cold and dry conditions until use. Recently, we developed a novel photolytic source of gas-phase NO3, in which it is generated via irradiation of aerated aqueous solutions of ceric ammonium nitrate and nitric acid. Here, we applied the method to generate and measure the yield and chemical composition of oxygenated volatile organic compounds (OVOCs) and secondary organic aerosol (SOA) obtained from NO3 oxidation of VOCs emitted from biogenic sources (isoprene, β-pinene, limonene and β-caryophyllene) and from biomass burning sources (phenol, catechol, guaiacol and syringol) in an oxidation flow reactor (OFR). Where possible, the composition and yields of OVOC/SOA obtained in the OFR studies were compared to those obtained from NO3 oxidation of the same precursors in environmental chamber studies.