HR: 1340h
AN: A53A-0150    [Abstracts]
TI: Atmospheric Aerosols: Cloud Condensation Nucleus Activity of Selected Organic Molecules
AU: * Rosenorn, T
EM: Thomas@Rosenoern.dk
AF: Department of Chemistry, University of Copenhagen Universitetsparken 5, Copenhagen, O 2100 Denmark
AU: Henning, S
EM: silvia.henning@tropos.de
AF: Institute for Tropospheric Research, Permoserstr. 15, Leipzig, 04318 Germany
AU: Hartz, K H
EM: karah@andrew.cmu.edu
AF: Department of Chemical Engineering, Carnegie Mellon University, Pittsburgh, PA 15213 United States
AU: Kiss, G
EM: kissgy@almos.vein.hu
AF: Air Chemistry Group, University of Vaszprem P.O. Box 158, Veszprem, 8201 Hungary
AU: Pandis, S
EM: spyros@andrew.cmu.edu
AF: Department of Chemical Engineering, Carnegie Mellon University, Pittsburgh, PA 15213 United States
AU: Pandis, S
EM: spyros@andrew.cmu.edu
AF: Department of Chemical Engineering, University of Patras, Patras, 26504 Greece
AU: Bilde, M
EM: mbilde@kiku.dk
AF: Department of Chemistry, University of Copenhagen Universitetsparken 5, Copenhagen, O 2100 Denmark
AB: Gas/particle partitioning of vapors in the atmosphere plays a major role in both climate through micro meteorology and in the physical and chemical processes of a single particle. This work has focused on the cloud droplet activation of a number of pure and mixed compounds. The means used to investigate these processes have been the University of Copenhagen cloud condensation nucleus counter setup and the Carnegie Mellon University CCNC setup. The importance of correct water activity modeling has been addressed and it has been pointed out that the molecular mass is an important parameter to consider when choosing model compounds for cloud activation models. It was shown that both traditional K”hler theory and K”hler theory modified to account for limited solubility reproduce measurements of soluble compounds well. For less soluble compounds it is necessary to use K”hler theory modified to account for limited solubility. It was also shown that this works for mixtures of compounds containing both inorganic salts and dicarboxylic acids. It has also been shown that particle phase and humidity history is important for activation behavior of particles consisting of two slightly soluble organic substances (succinic and adipic acid) and a soluble salt (NaCl). Model parameters for terpene oxidation product cloud activation have been derived. These are based on two sets of average parameters covering monoterpene oxidation products and sesquiterpene oxidation products. All parameters except the solubility were estimated and an effective solubility was calculated as the fitting parameter. The average solubility of the model compound found for mono terpene oxidation products is similar to those of sodium chloride and ammonium sulfate; however the higher molecular weight leads to a slightly higher activation diameter at fixed supersaturation. On a molar basis the monoterpene oxidation products show a 1.5 times higher effective solubility than the sesquiterpene oxidation products.
DE: 0305 Aerosols and particles (0345, 4801, 4906)
DE: 4801 Aerosols (0305, 4906)
DE: 4906 Aerosols (0305, 4801)
SC: Atmospheric Sciences [A]
MN: Fall Meeting 2005