Atmospheric Chemistry and Physics www.atmos-chem-phys.net 1680-7316 1680-7324 7 2 2007 10.5194/acp-7-511-2007 http://www.atmos-chem-phys.net/7/511/2007/ http://www.atmos-chem-phys.net/7/511/2007/acp-7-511-2007.html http://www.atmos-chem-phys.net/7/511/2007/acp-7-511-2007.pdf 511 534 2007-01-26 Arctic smoke – record high air pollution levels in the European Arctic due to agricultural fires in Eastern Europe in spring 2006 A. Stohl ast@nilu.no T. Berg J. F. Burkhart A. M. Fjǽraa C. Forster A. Herber Ø. Hov C. Lunder W. W. McMillan S. Oltmans M. Shiobara D. Simpson S. Solberg K. Stebel J. Ström K. Tørseth R. Treffeisen K. Virkkunen K. E. Yttri Norwegian Institute for Air Research, Kjeller, Norway University of California, Merced, USA Alfred Wegener Institute, Bremerhaven, Germany Meteorological Institute, Oslo, Norway University of Maryland, Baltimore, USA Earth System Research Laboratory, NOAA, Boulder, USA National Institute of Polar Research, Tokyo, Japan Department of Applied Environmental Science, Stockholm University, Sweden Arctic Centre, University of Lapland, Finland Department of Chemistry, University of Oulu, Oulu, Finland now at: Norwegian University of Science and Technology, Trondheim, Norway In spring 2006, the European Arctic was abnormally warm, setting new historical temperature records. During this warm period, smoke from agricultural fires in Eastern Europe intruded into the European Arctic and caused the most severe air pollution episodes ever recorded there. This paper confirms that biomass burning (BB) was indeed the source of the observed air pollution, studies the transport of the smoke into the Arctic, and presents an overview of the observations taken during the episode. Fire detections from the MODIS instruments aboard the Aqua and Terra satellites were used to estimate the BB emissions. The FLEXPART particle dispersion model was used to show that the smoke was transported to Spitsbergen and Iceland, which was confirmed by MODIS retrievals of the aerosol optical depth (AOD) and AIRS retrievals of carbon monoxide (CO) total columns. Concentrations of halocarbons, carbon dioxide and CO, as well as levoglucosan and potassium, measured at Zeppelin mountain near Ny Ålesund, were used to further corroborate the BB source of the smoke at Spitsbergen. The ozone (O₃) and CO concentrations were the highest ever observed at the Zeppelin station, and gaseous elemental mercury was also elevated. A new O₃ record was also set at a station on Iceland. The smoke was strongly absorbing – black carbon concentrations were the highest ever recorded at Zeppelin – and strongly perturbed the radiation transmission in the atmosphere: aerosol optical depths were the highest ever measured at Ny Ålesund. We furthermore discuss the aerosol chemical composition, obtained from filter samples, as well as the aerosol size distribution during the smoke event. Photographs show that the snow at a glacier on Spitsbergen became discolored during the episode and, thus, the snow albedo was reduced. Samples of this polluted snow contained strongly elevated levels of potassium, sulphate, nitrate and ammonium ions, thus relating the discoloration to the deposition of the smoke aerosols. This paper shows that, to date, BB has been underestimated as a source of aerosol and air pollution for the Arctic, relative to emissions from fossil fuel combustion. 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