Bromine measurements in ozone depleted air over the Arctic Ocean

This detected Br₂ is identified as active bromine and represents a lower limit of the sum HOBr+Br₂. The measured active bromine is shown to likely be HOBr during daytime flights in the arctic. In the MBL over the Arctic Ocean, soluble bromide and active bromine were consistently elevated and ozone was depleted.

Ozone depletion and active bromine enhancement were confined to the MBL that was capped by a temperature inversion at 200–500 m altitude. In ozone-depleted air, BrO rarely exceeded 10 pptv and was always substantially lower than soluble bromide that was as high as 40 pptv. BrCl was rarely enhanced above the 2-pptv detection limit, either in the MBL, over Alaska, or in the arctic free troposphere.