AAAR 31st Annual Conference
October 8-12, 2012
Hyatt Regency Minneapolis
Minneapolis, Minnesota, USA
Abstract View
A Model Study on the CCN Activation of Multicomponent Organic Aerosols
ILONA RIIPINEN, Narges Rastak, Spyros Pandis, Carnegie Mellon University
Abstract Number: 391 Working Group: Aerosols, Clouds, and Climate
Abstract Organic compounds consitute a major fraction of atmospheric aerosol particles in both rural and urban environments. Knowledge on the cloud activation properties of these organic particles is thus needed for accurate predictions of cloud condensation nuclei (CCN) concentrations and furthermore the aerosol-cloud interactions. These predictions are, however, complicated by the multitude of organic compounds present in the atmosphere, many of which are still unknown. Theoretical approaches simplifying the behavior of these complex mixtures are thus needed for feasible, yet accurate enough, model calculations on the behaviour or organic CCN. We studied the CCN activation behaviour or multicomponent organic mixtures by applying the Köhler theory for complex organic aerosol particles with variable dry sizes and thermodynamic properties, such as solubility distributions of the constituents. We probed the conditions at which the complex organic particles were predicted to completely dissolve to water at the point of activation, as opposed to forming separate aqueous and insoluble phases in the activated cloud droplet. Our results can be used to simplify the behaviour complex organic mixtures, yielding accurate predictions of the CCN-activation of a given aerosol population with minimal computational effort.