AAAR 31st Annual Conference
October 8-12, 2012
Hyatt Regency Minneapolis
Minneapolis, Minnesota, USA
Abstract View
Thermodynamic Properties and Evaporation Kinetics of DOP, DEHS, and Oleic Acid Aerosols
ALAN SHIHADEH, Sarah Safieddine, Rawad Saleh, Andrey Khlystov, American University of Beirut
Abstract Number: 653 Working Group: Aerosol Chemistry
Abstract Recent thermodenuder-based approaches to studying aerosol volatility have allowed for decoupled determinations of thermodynamic and kinetic properties governing the phase partioning behavior of semi-volatile aerosols. These techniques have been applied to little-studied solid-phase organic aerosols of relevance to atmospheric air pollution, but have not been validated against better characterized systems such as DOP, DEHS, and oleic acid, for which saturation pressure or surface tension data are available or attainable through independent means. In this study we report vapor pressures, enthalpies of evaporation, evaporation coefficients, and surface tensions of DOP, DEHS, and oleic acid particles as determined using the Integrated Volume – Tandem DMA (IV-TDMA) method and compare them to values obtained by earlier investigators using other means. Contrary to common assumptions, we find that these aerosol systems exhibit evaporation coefficients of order 0.1, indicating an energy barrier to evaporation despite their liquid state. As a result, these aerosol systems exhibit higher volatility than reported in previous thermodenuder studies, all of which assumed an evaporation coefficient of unity. We also find that surface tensions obtained using the IV-TDMA are consistent with those found using macroscopic methods.