Record of North American boreal forest fires in northwest Greenland snow

Chemosphere. 2021 Aug:276:130187. doi: 10.1016/j.chemosphere.2021.130187. Epub 2021 Mar 6.

Abstract

We present boreal forest fire proxies in a northwest Greenland snowpit spanning a period of six years, from spring 2003 to summer 2009. Levoglucosan (C6H10O5) is a specific organic molecular marker of biomass burning caused by boreal forest fires. In this study, levoglucosan was determined via liquid chromatography/negative ion electrospray ionization-tandem mass spectrometry, wherein isotope-dilution and multiple reaction monitoring methods are employed. Ammonium (NH4+) and oxalate (C2O42-), traditional biomass burning proxies, were determined using two-channel ion chromatography. In the northwest Greenland snowpit, peaks in levoglucosan, ammonium, and oxalate were observed in snow layers corresponding to the summer-fall seasons of 2004 and 2005. Considered together, these spikes are a marker for large boreal forest fires. The levoglucosan deposited in the Greenland snow was strongly dependent on long-range atmospheric transportation. A 10-day backward air mass trajectory analysis supports that the major contributors were air masses from North America. In addition, satellite-derived carbon monoxide (CO) and ammonia (NH3) concentrations suggest that chemicals from North American boreal forest fires during the summer-fall of 2004 and 2005 were transported to Greenland. However, large boreal fires in Siberia in 2003 and 2008 were not recorded in the snowpit. The sub-annual resolution measurements of levoglucosan and ammonium can distinguish between the contributions of past boreal forest fires and soil emissions from anthropogenic activity to Greenland snow and ice.

Keywords: Ammonium; Boreal forest fire; Greenland snow; Levoglucosan; Oxalate.

MeSH terms

  • Air Pollutants* / analysis
  • Environmental Monitoring
  • Fires*
  • Greenland
  • North America
  • Siberia
  • Snow
  • Taiga
  • United States

Substances

  • Air Pollutants