An homologous series of low molecular weight dicarboxylic acids (C2-C11) have been measured in the arctic aerosol samples collected from July 1987 to June 1988 in Alert. Oxalic acid (C2) was found as the dominant species followed by malonic (C3) or succinic (C4) acid. At the time of polar sunrise, certain dicarboxylic acids in arctic haze aerosols became 5 to 20 times more abundant than in the preceding dark winter months. Furthermore, they are correlated with tropospheric ozone depletion events marked by particulate bromine. Here, we report, for the first time, observations of dicarboxylic acids in the polar atmosphere and discuss the formation of these organic acids in terms of photochemical oxidation of pollutant precursors that reach the Arctic by long range atmospheric transport from midlatitudes. ¿ American Geophysical Union 1995