AEROSOL CHEMICAL-COMPOSITION DURING TROPOSPHERIC OZONE DEPLETION AT NY ALESUND SVALBARD/

During spring 1995, aerosol filters were continuously sampled with a t emporal resolution of 4-24 h at the NILU Zeppelin Mountain Station (Ny Alesund/Svalbard) and analysed for bromide, major ions and methanesul fonic 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 obser ved. Peak f-Br levels (120 ng/m(3)) were almost equal to results of me asurements reported earlier from Alert and Barrow. Less pronounced O-3 depletion events occurring in early May were associated with a relati vely weak Br- enhancement. A good correlation of f-Br and simultaneous ly measured BrO was found ([BrO] = 2 [f-Br] on a per molecule basis), except for situations with near zero O-3.