Biomass burning is a major source of greenhouse\ud gases and influences regional to global climate. Pre-industrial\ud fire-history records from black carbon, charcoal and other\ud proxies provide baseline estimates of biomass burning at\ud local to global scales spanning millennia, and are thus use-\ud ful to examine the role of fire in the carbon cycle and\ud climate system. Here we use the specific biomarker levo-\ud glucosan together with black carbon and ammonium concen-\ud trations from the North Greenland Eemian (NEEM) ice cores\ud ◦◦\ud (77.49 N, 51.2 W; 2480ma.s.l) over the past 2000 years to infer changes in boreal fire activity. Increases in boreal fire activity over the periods 1000–1300 CE and decreases during 700–900 CE coincide with high-latitude NH temper- ature changes. Levoglucosan concentrations in the NEEM ice cores peak between 1500 and 1700 CE, and most levo- glucosan spikes coincide with the most extensive central and northern Asian droughts of the past millennium. Many of these multi-annual droughts are caused by Asian mon- soon failures, thus suggesting a connection between low- and high-latitude climate processes. North America is a primary source of biomass burning aerosols due to its relative prox-\ud imity to the Greenland Ice Cap. During major fire events, however, isotopic analyses of dust, back trajectories and links with levoglucosan peaks and regional drought reconstruc- tions suggest that Siberia is also an important source of py- rogenic aerosols to Greenland

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Amino acids are significant components of atmospheric aerosols, affecting organic nitrogen input to marine ecosystems, atmospheric radiation balance, and the global water cycle. The wide range of amino acid reactivities suggest that amino acids may serve as markers of atmospheric transport and deposition of particles. Despite this potential, few measurements have been conducted in remote areas to assess amino acid concentrations and potential sources. Polar regions offer a unique opportunity to investigate atmospheric processes and to conduct source apportionment studies of such compounds. In order to better understand the importance of amino acid compounds in the global atmosphere, we determined free amino acids (FAAs) in seventeen size-segregated aerosol samples collected in a polar station in the Svalbard Islands from 19 April until 14 September 2010. We used an HPLC coupled with a tandem mass spectrometer (ESI-MS/MS) to analyze 20 amino acids and quantify compounds at fmol m⁻³ levels. Mean total FAA concentration was 1070 fmol m⁻³ where serine and glycine were the most abundant compounds in almost all samples and accounted for 45–60% of the total amino acid relative abundance. The other eighteen compounds had average concentrations between 0.3 and 98 fmol m⁻³. The higher amino acid concentrations were present in the ultrafine aerosol fraction (< 0.49 μm) and accounted for the majority of the total amino acid content. Local marine sources dominate the boreal summer amino acid concentrations, with the exception of the regional input from Icelandic volcanic emissions

A method for the direct determination of levoglucosan at the picogram per milliliter level in less than 1 mL of Antarctic ice has been developed. Chemical analysis is performed by high-performance liquid chromatography with triple quadrupole tandem mass spectrometric detection. Levoglucosan, a specific molecular marker for biomass burning, is identified by negative ion electrospray mass spectrometry using m/z 161/113, 161/101, 161/85, and 161/71 as monitoring ion transitions. Contamination problems were carefully taken into account by adopting ultraclean procedures during sampling and sample pretreatment phases. The limit of detection is 3 pg mL(-1) (0.3 pg absolute amount injected); the repeatability ranges between 20% and 50% at a concentration of 20 and 9 pg mL(-1), respectively. This methodology allowed the direct determination of levoglucosan in a 1 mL sample of Antarctic ice with concentration ranges between 4 and 30 pg mL(-1). To our knowledge these are the first levoglucosan concentrations reported for Antarctic ice.

We demonstrate the use of levoglucosan (1,6-anhydro-β-d-glucopyranose) as a source-specific proxy of past fire activity in snow pits and ice cores. Levoglucosan is unambiguously a degradation product derived from cellulose burning at temperatures greater than 300 °C and is widely used as a biomass burning marker in aerosol analyses. We analyse samples collected from a 3 m snow pit at Summit, Greenland (72°20′N, 38°45′W; 3270 m a.s.l.), with a known depositional history where biomass burning aerosols were traced from their source in a Canadian smoke plume, through their eastward transport and deposition on the Greenland ice sheet, and their eventual burial by accumulating snow layers. The snow pit levoglucosan profile replicates oxalate concentrations from a known forest fire event, suggesting the applicability of levoglucosan as a marker of past fire activity in snow and by extension in ice cores. However, levoglucosan concentration peaks in the snow pit differ from those of ammonium and potassium, which are traditionally used as biomass burning proxies in snow and ice studies but which incorporate sources other than fire activity. The source specificity of levoglucosan can help determine the past relative contribution of biomass burning aerosols when used in conjunction with other proxies in snow and ice