AAAR 31st Annual Conference
October 8-12, 2012
Hyatt Regency Minneapolis
Minneapolis, Minnesota, USA
Abstract View
Coatings on Light Absorbing Aerosols: Optical Effects, Morphology, and Composition
LULU MA, Hao Tang, Jonathan Thompson, Texas Tech University
Abstract Number: 369 Working Group: Aerosols, Clouds, and Climate
Abstract Atmospheric aerosols are often internally mixed when dispersed in earth’s atmosphere. Internally mixed particles can exhibit very different physical properties when directly compared with their more chemically pure counterparts. For instance, mixing hydrocarbon – like material with sulfates can vastly alter hygroscopicity, and several investigators have suggested light absorption can increase when light absorbing cores are embedded within non-absorbing coatings. This presentation will outline what we have learned about the fundamental physical processes that occur when a coated, light-absorbing particle interacts with an intense beam of electromagnetic radiation. We will present results of a TEM and SMPS study that addresses beam-induced morphology changes for select particle types. In addition, cavity ring down spectrometry (CRDS) combined with nephelometry has been used to probe extinction and scattering coefficients of aerosols at 532 nm with and without the intense laser illumination. This allows an assessment of changes in optical properties induced by the intense beam. In addition, a discussion of laser irradiance required to observe such changes will be undertaken.