Chemical aging of biomass burning aerosol surrogates due to oxidation by O ₃, NO ₂, NO ₃, and N ₂O ₅

Here we present a study on the heterogeneous kinetics between typical compounds of biomass burning aerosol (BBA) and atmospheric trace gases such as O ₃, NO ₂, NO ₃, and N ₂O ₅. Levoglucosan, abietic acid, nitroguaiacol, and a mixture of these species serve as BBA surrogates. Levoglucosan and abietic acid are typically employed biomolecular markers for BBA source apportionment studies. The heterogeneous kinetics are investigated under dry and humid conditions using a chemical ionization mass spectrometer coupled to a rotating-wall flow-tube reactor. The uptake coefficient, γ, for the uptake of N ₂O ₅ is on the order of 10 ^-5 whereas γ for the uptake of NO ₃ is on the order of 10 ^-3. The uptakes of NO ₃ as a function of exposure time indicate Langmuir-Hinshelwood type reaction mechanisms which are modeled and interpreted using the flux-based Poschl-Rudich-Ammann framework to yield atmospheric lifetime estimates.