Just recently (April 26, 2013), scientists have been studying the excessive release of the element bromine in polar regions, indicating that this element comes from snow and ice. However, the bromine content of snow and ice is relatively low and although the whole polar ice cap releases bromine in the lower atmosphere, it is still not enough to cause severe depletion of the ozone. My question is, where do these large amounts of bromine in the lower atmosphere come from considering that polar regions are dense in carbon and not in bromine. It is interesting for me since bromine compounds are considered significant contributors to the depletion of ozone in the lower atmosphere, which is one of the most contentious topics in ecology.
Also, how are salts transported from the ocean and oxidized to become reactive halogen species in the air? And let's say, bromine explosion is a natural occurrence, and there are different reactivity of halogens as compared to OH and ozone, would the effect on the ozone be better or worse if other halogens, such as chlorine and iodine, are activated through mechanisms which are coupled to bromine chemistry?
The bromine comes from bromide salts naturally present in ocean water, probably via sea spray. One point of the paper you mention is that the snow creates the interface - provides the OH- ions necessary, I assume - that converts the bromide into bromine gas - once there is sunlight (UV light). This typically occurs in the atmosphere, however the vapor content in the polar regions is extremely low due to the cold.
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