American Chemical Society
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Products and Secondary Organic Aerosol Yields from the OH and NO3 Radical-Initiated Oxidation of Resorcinol

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journal contribution
posted on 2019-06-13, 00:00 authored by Zachary Finewax, Joost A. de Gouw, Paul J. Ziemann
Resorcinol (1,3-benzenediol) has been observed in both laboratory and field studies reporting biomass burning emissions. As a result of its low vapor pressure, it has been suggested as a secondary organic aerosol (SOA) precursor, but its gas-phase oxidation has not been studied previously. Here, the reactions of resorcinol with OH radicals in the presence of NOx and with NO3 radicals in the presence of NO2 were investigated to mimic oxidation under daytime and nighttime conditions. When resorcinol was added to the chamber in the presence of a high concentration of oxidant, the gas-phase chemistry of this highly reactive, low-volatility compound was investigated while minimizing its loss to the chamber walls. Gas- and particle-phase products were identified using a combination of thermal desorption particle beam mass spectrometry, chemical ionization–ion trap mass spectrometry, and proton transfer reaction–mass spectrometry. The major products identified were benzenetriol, nitrobenzenetriol, and hydroxymuconic semialdehyde in the particle phase and hydroxybenzoquinone and nitroresorcinol in the gas phase, and a reaction mechanism was developed to explain their formation. Hydroxybenzoquinone was determined to form through gas-phase oxidation of resorcinol and by heterogeneous oxidation of benzenetriol by nitric acid. Reactions with OH and NO3 radicals produced SOA with yields of 0.86 and 0.09, respectively, but these values should be somewhat lower in the atmosphere where aerosol mass concentrations are lower and, thus, gas–particle partitioning is reduced.