Arctic smoke ndash; record high air pollution levels in the European Arctic due to agricultural fires in Eastern Europe in spring 2006

摘要

In spring 2006, the European Arctic was abnormally warm, setting newhistorical temperature records. During this warm period, smoke fromagricultural fires in Eastern Europe intruded into the European Arctic andcaused the most severe air pollution episodes ever recorded there. This paperconfirms that biomass burning (BB) was indeed the source of the observed airpollution, studies the transport of the smoke into the Arctic, and presentsan overview of the observations taken during the episode. Fire detectionsfrom the MODIS instruments aboard the Aqua and Terra satellites were used toestimate the BB emissions. The FLEXPART particle dispersion model was used toshow that the smoke was transported to Spitsbergen and Iceland, which wasconfirmed by MODIS retrievals of the aerosol optical depth (AOD) and AIRSretrievals of carbon monoxide (CO) total columns. Concentrations ofhalocarbons, carbon dioxide and CO, as well as levoglucosan and potassium,measured at Zeppelin mountain near Ny Ålesund, were used to furthercorroborate the BB source of the smoke at Spitsbergen. The ozone (O) andCO concentrations were the highest ever observed at the Zeppelin station, andgaseous elemental mercury was also elevated. A new O record was also setat a station on Iceland. The smoke was strongly absorbing – black carbonconcentrations were the highest ever recorded at Zeppelin – and stronglyperturbed the radiation transmission in the atmosphere: aerosol opticaldepths were the highest ever measured at Ny Ålesund. We furthermorediscuss the aerosol chemical composition, obtained from filter samples, aswell as the aerosol size distribution during the smoke event. Photographsshow that the snow at a glacier on Spitsbergen became discolored during theepisode and, thus, the snow albedo was reduced. Samples of this polluted snowcontained strongly elevated levels of potassium, sulphate, nitrate andammonium ions, thus relating the discoloration to the deposition of the smokeaerosols. This paper shows that, to date, BB has been underestimated as asource of aerosol and air pollution for the Arctic, relative to emissionsfrom fossil fuel combustion. Given its significant impact on air quality overlarge spatial scales and on radiative processes, the practice of agriculturalwaste burning should be banned in the future.