HR: 0800h
AN: A51D-0741    [Abstracts]
TI: Effects of Relative Humidity and Carbon Monoxide on the ozone-initiated Reaction of Gaseous Mercury: Kinetic & product studies
AU: * Snider, G
EM: graydon.snider@mcgill.ca
AF: McGill University, 801 Sherbrooke Street West Montreal, Quebec, Canada Otto Maass, Montreal, QC H3A 2K6, Canada
AU: Raofie, F
EM: farhad.raofie@mcgill.ca
AF: McGill University, 801 Sherbrooke Street West Montreal, Quebec, Canada Otto Maass, Montreal, QC H3A 2K6, Canada
AU: Ariya, P A
EM: parisa.ariya@mcgill.ca
AF: McGill University, 801 Sherbrooke Street West Montreal, Quebec, Canada Otto Maass, Montreal, QC H3A 2K6, Canada
AB: Ozone is assumed to be the predominant tropospheric oxidant of (Hg⁰(g)), defining mercury global atmospheric lifetime. In this study, for the first time, we have examined the effect of H₂O(g) and CO(g) on the bi-molecular O₃-initiated oxidation of rate of Hg⁰(g), k_net, at 296K. Kinetics of these reactions were studied as absolute rates using gas chromatography coupled to mass spectrometry (GC-MS) at different concentration regimes, surface-to-volume ratios, and wall treatments. We observed a maximum 170% increase in the rate constant at 60% RH in a 1L flask, and smaller increases at other humidities, in larger flask volumes the significance of RH decreased in contrast with the experiments where CO was used as the third body. Product studies were performed using mass spectrometry and high resolution transmission electron microscopy coupled to an electron dispersive spectrometer (HRTEM-EDS). Our results give evidence for enhanced chain growth of HgO(s) on a carbon grid at RH = 50%. The atmospheric implications of our findings will be discussed.
DE: 0317 Chemical kinetic and photochemical properties
DE: 0365 Troposphere: composition and chemistry
DE: 6235 Mercury
SC: Atmospheric Sciences [A]
MN: 2007 Fall Meeting