Aerosol chemical composition during tropospheric ozone depletion at Ny Ålesund/Svalbard

During spring 1995, aerosol filters were continuously sampled with a temporal resolution of 4–24 h at the NILU Zeppelin Mountain Station (Ny Alesund/Svalbard) and analysed for bromide, major ions and methanesulfonic acid (MSA). During a strong ozone depletion event at the end of April, a corresponding increase in the non-sea salt Br − exceeding the typical background level by more than one order of magnitude was observed. Peak f-Br levels (120 ng/m 3 ) were almost equal to results of measurements reported earlier from Alert and Barrow. Less pronounced O 3 depletion events occurring in early May were associated with a relatively weak Br − enhancement. A good correlation of f-Br and simultaneously measured BrO was found ([BrO]= 2 [f-Br] on a per molecule basis), except for situations with near zero O 3 . DOI: 10.1034/j.1600-0889.49.issue5.5.x