The morphology of organic aerosol particles has consequences for aerosol optical properties, mass accommodation, cloud condensation and ice nucleation activity, and heterogeneous chemistry.  We use cryo-transmission electron microscopy to investigate the phase separation behavior of dry, submicron particles composed of carboxylic acids, organic alcohols, and ammonium sulfate.  We have found that phase separation behavior is dependent on the aqueous solubility of the organic compound, where highly soluble organic compounds form homogeneous morphologies and low solubility organic compounds form phase separated morphologies.  Organic compounds of intermediate solubility form phase separated morphologies at large diameters and homogeneous structures at small diameters.  Using cavity ring-down spectroscopy (CRDS), we have determined that particles with partially engulfed and core shell morphologies have similar extinction cross sections.  In addition, we have explored the extent to which CRDS can resolve phase separated and homogeneous morphologies.  We will discuss the implications of our results for aerosol radiative properties.

Phase separation in submicron organic aerosol and consequences for aerosol optical properties

248th National Meeting (2014)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.