Multi-phase SOA Formation

Recent modeling of field studies using vapor pressure partitioning shows that models correctly estimate the amount of secondary organic aerosol (SOA) but do not provide accurate aerosol chemical parameters. Some sources of SOA formation, including formation in aerosol water, are not currently included in models. We examine SOA formation from aqueous phase processing using glyoxal, a small molecule with a very high vapor pressure and a very high water solubility, using a combination of modeling (Methods/Chemical Modeling) and lab studies (PSI 2009, 2011, 2013).

Aqueous-phase Modeling

Explicit aqueous-phase models are used to explain the results of chamber studies and predict ambient multiphase chemistry from field studies. This Figure shows model results predicting Henry’s law values and product distribution during chamber experiments at PSI. Inputs include measurements of glyoxal from the LED-CE-DOAS and filter measurements. The results predict speciated glyoxal SOA contributions including whether or not they form SOA irreversibly.