NO3/N2O­5 Fate during the 2013 Southern Oxidant and Aerosol Study

Nitrate radical (NO3) was found to be a significant oxidant of biogenic volatile organic compounds (BVOCs) at the Southern Oxidant and Aerosol Study (SOAS), conducted in Summer 2013. NO3 + BVOC reactions were responsible for a substantial (50%) fraction of losses even during daylight hours when photolysis and NO reactions are rapid NO3 sinks. Steady-state calculated NO3 and measured BVOC concentrations were used to predict accumulated NO3 loss and these values were correlated with total gas- and aerosol-phase alkyl nitrate measurements taken with TD-LIF and aerosol organic nitrate mass measured by Aerosol Mass Spectrometry (AMS). This enabled determination of the BVOCs most responsible for NO3 loss during periods of aerosol growth. Further correlations with specific organonitrates measured by Chemical Ionization Mass Spectrometry (CIMS) allow assignment of several individual product molecules connected to secondary organic aerosol formation in the southeastern United States.