Molecular composition of fresh and aged secondary organic aerosol from a mixture of biogenic volatile compounds: a high-resolution mass spectrometry study

摘要: Abstract. Field observations over the past decade indicate that a significant fraction of organic aerosol in remote areas may contain highly oxidized molecules. Aerosol processing or further oxidation (aging) has been suggested to be responsible for their formation through heterogeneous reaction with oxidants and multigenerational vapours by OH radicals. In this study we investigated influence several aging processes on molecular composition secondary aerosols (SOA) using direct infusion liquid chromatography high-resolution mass spectrometry. SOA was formed simulation chamber experiments from ozonolysis mixture four biogenic volatile compounds (BVOC): α-pinene, β-pinene, Δ3-carene isoprene. The subsequently aged under three different sets conditions: dark presence residual ozone, UV irradiation radicals, light only. Among all studied conditions, only radical-initiated found showed an increase carbon state (OSC) elemental O / C ratios components. None produced observable effect oligomers BVOC mixture, which were equally abundant both "fresh" "aged" SOA. Additional α-pinene as sole precursor demonstrated are important group processes; however, completely set is these two regimes. OH-initiated had significantly higher overall OSC compared pure confirming radical more likely occurrence species ambient