HR: 0830h
AN: A51F-0758    [PDF]
TI: Deliquescence and Efflorescence of Organic and Mixed Organic-Inorganic Particles: An FTIR/Optical Microscopy Approach
AU: * Parsons, M T
EM: matt@chem.ubc.ca
AF: Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, BC V6T1Z1 Canada
AU: Fok, A
AF: Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, BC V6T1Z1 Canada
AU: Mak, J
AF: Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, BC V6T1Z1 Canada
AU: Lipetz, S R
AF: Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, BC V6T1Z1 Canada
AU: Pant, A
AF: Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, BC V6T1Z1 Canada
AU: Bertram, A K
EM: bertram@chem.ubc.ca
AF: Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, BC V6T1Z1 Canada
AU: Haddrell, A
AF: Department of Chemistry, Simon Fraser University, 8888 University Drive, Burnaby, BC V5A1A6 Canada
AU: Agnes, G R
AF: Department of Chemistry, Simon Fraser University, 8888 University Drive, Burnaby, BC V5A1A6 Canada
AB: Organic aerosols have recently gained attention as a significant component of the atmosphere and as such have been the focus of a number of studies regarding phase transitions. We have focussed on the deliquescence and efflorescence behaviour of dicarboxylic acids using optical microscopy in conjunction with a flow cell containing particles with diameters ranging from 2 - 40 microns. Deliquescence of malonic acid, succinic acid, glutaric acid and adipic acid particles were tested over a range of temperature from 253 K to 293 K. In all cases, we observed deliquescence below the eutectic point, suggesting that these species are not good ice nuclei above 253 K. Our deliquescence data is also in good agreement with calculations based on solubility and the UNIFAC model. Deliquescence and efflorescence data for ammonium sulphate - glutaric acid and sodium chloride - glutaric acid mixtures were also measured at 293 K using both optical and FTIR microscopy techniques. FTIR microscopy allows us to make visual observations, while monitoring the chemical content of a single particle or a collection of particles. Additionally, we have extended the FTIR microscopy technique to study phase transition behaviour of single electrodynamically levitated particles. Some preliminary results from this new technique are also discussed.
DE: 0305 Aerosols and particles (0345, 4801)
DE: 0320 Cloud physics and chemistry
DE: 0394 Instruments and techniques
SC: Atmospheric Sciences [A]
MN: 2003 Fall Meeting