Purdue Climate Change Research Center

Studies of the Production of Molecular Halogens in Arctic Snowpacks and on Sea Ice Surfaces

Funded by the National Science Foundation


This project would involve field experiments at Barrow, AK, aimed at improving understanding of the oxidation of the sea salt halides, chloride and bromide, into the molecular halogens, Cl2, BrCl, and Br2. In the Arctic at spring time there is a dramatic phenomenon characterized by the complete loss of ozone from the lowest layer of the atmosphere, along with near-complete loss of atmospheric elemental mercury. The elemental mercury is oxidized to short-lived products that then deposit to the surface, where it can enter and damage sensitive ecosystems. These ozone depletion episodes (ODEs) and mercury depletion episodes (MDEs) are known to occur as a result of halogen atom chemistry.


  • Paul Shepson

Contact Information

Purdue University
203 S. Martin Jischke Drive
MANN 105
West Lafayette, IN 47907