HR: 14:55h
AN: A53E-06    [Abstracts]
TI: Uptake of Organics by Water Aerosols Measured in a Low Pressure Aerosol Reactor
AU: Remorov, R G
EM: rremorov@sciborg.uwaterloo.ca
AF: University of Waterloo, Waterloo Centre for Atmospheric Sciences, Waterloo, ON N2L3G1 Canada
AU: Zasetsky, A Y
EM: azaset@sciborg.uwaterloo.ca
AF: University of Waterloo, Waterloo Centre for Atmospheric Sciences, Waterloo, ON N2L3G1 Canada
AU: Bardwell, M W
EM: mbardwel@scimail.uwaterloo.ca
AF: University of Waterloo, Waterloo Centre for Atmospheric Sciences, Waterloo, ON N2L3G1 Canada
AU: * Sloan, J J
EM: sloanj@UWaterloo.CA
AF: University of Waterloo, Waterloo Centre for Atmospheric Sciences, Waterloo, ON N2L3G1 Canada
AB: Uptake of trace gases by water aerosols (0.1-20 $\mu$m in diameter) was studied using a unique, newly-developed low pressure aerosol reactor that provides simultaneous measurements of both aerosol surface area density and gas phase concentration. This apparatus uses a spray atomizer to generate aerosols at pressures down to about 30 Torr and a fast flow reactor for kinetic studies. The number density and size distribution of the aerosol particles are determined from their infrared spectra. Mass spectrometry is used to monitor the concentrations of gas phase components. Decay kinetics are determined by monitoring the disappearance rates of the gas phase species as a function of the aerosol surface area. This technique has been used to investigate the uptake of acetone at room temperature and a pressure of 36.4 Torr. The direct uptake measurements are combined with calculations of the diffusion of acetone in the liquid droplets to determine $\alpha$, the mass accommodation coefficient. A value of $\alpha$ = 3.6(-2/+3.1) x 10$^{-3}$. was found in this way. The capabilities and advantages of the method will be discussed.
DE: 0305 Aerosols and particles (0345, 4801)
DE: 0317 Chemical kinetic and photochemical properties
DE: 0320 Cloud physics and chemistry
DE: 0365 Troposphere--composition and chemistry
DE: 0394 Instruments and techniques
SC: Atmospheric Sciences [A]
MN: 2004 AGU Fall Meeting