Surface snow serves as a source of the chemical bromine to the Arctic atmosphere in polar spring, reports a study published online this week in Nature Geoscience. The findings suggest that surface snow contributes to the destruction of atmospheric ozone in the Arctic following polar sunrise.

Kerri Pratt and colleagues assessed the potential for bromine production from various icy surfaces in Alaska. They find that snow that accumulates on first-year sea ice and tundra releases significant quantities of bromine, but only in the presence of sunlight. They suggest that this sunlight-induced production of bromine in surface snow contributes to the episodic depletion of atmospheric ozone at the poles.

In an accompanying News and Views article, Jon Abbatt says that the “findings lend much more confidence to the suggestion that halogens released from icy surfaces help to explain polar ozone depletion events”.