Abstract Number: 746 Working Group: Aerosol Chemistry
Abstract Carbonyl-containing volatile organic compounds (e.g. acetaldehyde, glyoxal, methylgloxal, etc.) are known to form surface-active SOA products upon uptake into aqueous aerosols, followed by subsequent aerosol-phase reactions. As aerosol surface tension is participatory in several indirect radiative forcing effects, accurate representation of how surface tensions shifts throughout a droplet's lifetime is paramount to properly characterizing the effects of a given VOC on aerosol properties. Here, we measure surface tension dynamics of hanging ammonium sulfate droplets when exposed to controlled organic concentration and RH gas flows. By using small (<25µL) volumes, the relative surface area to volume ratios are more representative of aerosols than bulk mimic solutions; conversely, single drops are easier to control and can be directly observed as opposed to aerosol chamber studies that necessitate filter collection or similar aggregate measurements. Observed surface tension is compared to S-L estimations via GAMMA, a 0-dimensional computational box model; the discrepancy between inferred bulk concentration via observed surface tension and inferred bulk concentration via aerosol uptake and processing is explored.