HR: 08:15h
AN: A11E-02    [Abstracts]
TI: Effect of Humidity on Nitric Acid Uptake on Mineral Dust Aerosol Particles
AU: * Vlasenko, A
EM: alexander.vlasenko@psi.ch
AF: Paul Scherrer Institute, Laboratory of Radio- and Environmental Chemistry, Villigen, 5232 Switzerland
AU: Sjoegren, S
EM: staffan.sjoegren@psi.ch
AF: Paul Scherrer Institute, Laboratory of Atmospheric Chemistry, Villigen, 5232 Switzerland
AU: Weingartner, E
EM: ernest.weingartner@psi.ch
AF: Paul Scherrer Institute, Laboratory of Atmospheric Chemistry, Villigen, 5232 Switzerland
AU: Stemmler, K
EM: konrad.stemmler@psi.ch
AF: Paul Scherrer Institute, Laboratory of Radio- and Environmental Chemistry, Villigen, 5232 Switzerland
AU: Gaeggeler, H W
EM: heinz.gaeggeler@iac.unibe.ch
AF: University of Bern, Department of Chemistry and Biochemistry, Bern, 3012 Switzerland
AU: Ammann, M
EM: markus.ammann@psi.ch
AF: Paul Scherrer Institute, Laboratory of Radio- and Environmental Chemistry, Villigen, 5232 Switzerland
AB: Heterogeneous interactions between atmospheric trace gases and aerosols are important in several issues of atmospheric chemistry. This processing might affect the chemical and physical properties of the aerosol; on the other hand, it may also impact the global budget of important trace gas compounds. Among the many potential reactions occurring, the reaction of mineral dust aerosol with HNO₃ might be very important as it affects the ozone budget of the upper troposphere. This reaction is also of significant interest because it converts barely soluble dust components into very soluble inorganic nitrates, which can therefore affect the properties of dust as cloud condensation nuclei or ice nuclei, as well as their optical properties. Here we present the laboratory observations of HNO₃ uptake by airborne mineral dust particles. The model aerosols were generated by dry dispersion of Arizona Test Dust, SiO₂ and by nebulising a saturated solution of calcium carbonate. The uptake of gaseous nitric acid was observed in the flow reactor at room temperature and atmospheric pressure. The reaction kinetics was studied at different nitric acid gas concentrations and aerosol surface areas. Aging experiments at high RH showed the formation of a water soluble coating and an enhancement of the hygroscopicity of the dust particles. The major atmospheric implication of this study is the experimentally determined humidity dependence of the heterogeneous uptake on dust aerosol.
DE: 0305 Aerosols and particles (0345, 4801, 4906)
DE: 0317 Chemical kinetic and photochemical properties
DE: 0365 Troposphere: composition and chemistry
DE: 0368 Troposphere: constituent transport and chemistry
SC: Atmospheric Sciences [A]
MN: Fall Meeting 2005