Bromine release in the high Arctic: what is the impact of Arctic haze?

Exponential build-up of bromine in the polar troposphere is linked to severe multi-day ozone depletion events in springtime. Recent research suggests that the snowpack and aerosols are the main sources of bromine, but the exact mechanisms of, and conditions required for these 'bromine explosions' are not well understood. The proposed reactions require low pH to proceed. Snow is naturally acidic, but an additional source of snow acidification is the Arctic haze, springtime pollution transported to the polar regions from north-eastern Europe and Siberia. Acidic haze aerosol could potentially contribute to bromine release, but the connections between the two phenomena have not been studied explicitly. We present observations of bromine monoxide (BrO) and aerosols from Eureka, Nunavut, Canada (80.1° N, 86.4° W). Bromine explosions were observed in March 2016 and March 2017, and in several cases the BrO enhancement coincided with the arrival of haze layers to the measurement site. This work investigates the potential links between bromine release and Arctic haze.