Advertisement

Size distributions of dicarboxylic acids and inorganic ions in atmospheric aerosols collected during polar sunrise in the Canadian high Arctic

Authors

  • Kimitaka Kawamura,

    1. Institute of Low Temperature Science, Hokkaido University, Sapporo, Japan
    Search for more papers by this author
  • Masahiro Narukawa,

    1. Institute of Low Temperature Science, Hokkaido University, Sapporo, Japan
    2. Graduate School of Environmental Earth Science, Hokkaido University, Sapporo, Japan
    3. Now at Heat and Fluid Dynamics Department, Research Laboratory, IHI Co., Ltd., Yokohama, Japan.
    Search for more papers by this author
  • Shao-Meng Li,

    1. Air Quality Research Division, Atmospheric Science and Technology Directorate, Science and Technology Branch, Environment Canada, Toronto, Ontario, Canada
    Search for more papers by this author
  • Leonard A. Barrie

    1. Air Quality Research Division, Atmospheric Science and Technology Directorate, Science and Technology Branch, Environment Canada, Toronto, Ontario, Canada
    2. Now at Atmospheric Research and Environment Programme, World Meteorological Organization, Geneva, Switzerland.
    Search for more papers by this author

Abstract

[1] Size-segregated atmospheric aerosols (11 stages separating particles from <0.04 to >14.2 μm) collected in the Arctic during the polar sunrise at Alert were analyzed for aerosol mass, dicarboxylic acids, and major inorganic ions. Oxalic, malonic, succinic, and glutaric acids were detected in all size ranges, with oxalic acid being dominant. Their concentrations maximized in the accumulation mode either at 0.24–0.40 or 0.40–0.8 μm aerodynamic diameters, suggesting that diacids were mainly formed by gas-to-particle conversion via photochemical oxidation of nonmethane hydrocarbons and oxygenated organics originated from continental pollution sources. The relative abundances of oxalic acid were higher in the 0.24- to 0.4-μm size particles (73–78%) than in supermicrometer particles (40–60%), indicating that oxalic acid is produced by gas phase oxidation of precursors followed by accumulation on preexisting particles. Mass size distributions of NH4+ and SO42− peaked in the accumulation mode similar to those of small diacids. The sea-salt enrichment factor of K+ (biomass burning tracer) relative to Na+ maximized in 0.1- to 0.8-μm sizes, whereas those of Mg2+ and Ca2+ (dust tracers) in 0.4- to 7.8-μm particles. Maximized chlorine loss and bromine enrichment were found at 0.4–0.8 and 0.24–0.4 μm sizes, respectively. Concentrations of Br, which typically showed a submicrometer maximum, increased significantly during an O3 depletion event having a shift of size distribution to a supermicrometer mode. During this event, oxalic acid concentration relative to succinic acid increased in submicrometer mode (0.24–0.4 μm), adding to a growing body of evidence supporting the hypothesis that halogen chemistry is important in the production and loss of oxalic acid in the arctic atmosphere.

Ancillary