Submitted on April 7, 2008
Accepted on June 9, 2008
N2O5 Oxidizes Chloride to Cl2 in Acidic Atmospheric Aerosol
James M. Roberts 1, Hans D. Osthoff 2, Steven S. Brown 1, A. R. Ravishankara 3
1 Chemical Sciences Division, Earth System Research Laboratory, National Oceanic and Atmospheric Administration, Boulder, Colorado, USA.
2 Chemical Sciences Division, Earth System Research Laboratory, National Oceanic and Atmospheric Administration, Boulder, Colorado, USA.; Cooperative Institute for Research in the Environmental Sciences, NOAA and the University of Colorado, Boulder, Colorado, USA.; now at the Department of Chemistry, University of Calgary, Calgary, Alberta, Canada.
3 Chemical Sciences Division, Earth System Research Laboratory, National Oceanic and Atmospheric Administration, Boulder, Colorado, USA.; Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado, USA.
Molecular chlorine (Cl2) is an important yet poorly understood trace constituent of the lower atmosphere. Although a number of mechanisms have been proposed for the conversion of particle-bound chloride (Cl–) to gas-phase Cl2, the detailed processes involved remain uncertain. Here, we show that reaction of dinitrogen pentoxide (N2O5) with aerosol phase chloride yields Cl2 at low pH (<2) and should constitute an important halogen activation pathway in the atmosphere.
