Quantifying black carbon from biomass burning by means of levoglucosan – a one-year time series at the Arctic observatory Zeppelin

Levoglucosan, a highly specific tracer of particulate matter from biomass burning, has been used to study the influence of residential wood burning, agricultural waste burning and Boreal forest fire emissions on the Arctic atmosphere black carbon (BC) concentration. A one-year time series from March 2008 to March 2009 of levoglucosan has been established at the Zeppelin observatory in the European Arctic. Elevated concentrations of levoglucosan in winter (mean: 1.02 ng m−3) compared to summer (mean: 0.13 ng m−3) were observed, resembling the seasonal variation seen for e.g. sulfate and BC. The mean concentration in the winter period was 2–3 orders of magnitude lower than typical values reported for European urban areas in winter, and 1–2 orders of magnitude lower than European rural background concentrations. Episodes of elevated levoglucosan concentration lasting from 1 to 6 days were more frequent in winter than in summer and peak values were higher, exceeding 10 ng m−3 at the most. Concentrations of elemental carbon from biomass burning (ECbb) were obtained by combining measured concentrations of levoglucosan and emission ratios of levoglucosan and EC for wildfires/agricultural fires and for residential wood burning. Neglecting chemical degradation by OH provides minimum levoglucosan concentrations, corresponding to a mean ECbb concentration of 3.7 ± 1.2 ng m−3 in winter (October–April) and 0.8 ± 0.3 ng m−3 in summer (May–September), or 8.8 ± 4.5% of the measured equivalent black carbon (EBC) concentration in winter and 6.1 ± 3.4% in summer. When accounting for chemical degradation of levoglucosan by OH, an upper estimate of 31–45% of EBC could be attributed to ECbb* (ECbb adjusted for chemical degradation) in winter, whereas no reliable (