N2O5 Oxidizes Chloride to Cl2 in Acidic Atmospheric Aerosol
James M. Roberts,1*
Hans D. Osthoff,1,2
Steven S. Brown,1
A. R. Ravishankara1,3
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.
1 Chemical Sciences Division, Earth System Research Laboratory, National Oceanic and Atmospheric Administration (NOAA), Boulder, CO 80305, USA.
2 Cooperative Institute for Research in the Environmental Sciences, NOAA, and the University of Colorado, Boulder, CO 80309, USA.
3 Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO 80309, USA.
Present address: Department of Chemistry, University of Calgary, Calgary, Alberta T2N 1N4, Canada.
* To whom correspondence should be addressed. E-mail: James.M.Roberts{at}noaa.gov
