Characterization of Two Biomass Burning Episodes Affecting Air Quality in Beijing

Atmospheric concentrations of levoglucosan, a molecular marker for biomass burning, were determined by gas chromatography-mass spectrometry(GC/MS) for 31 Beijing total suspended particle(TSP) samples collected during 2005—2006. The average concentration of downtown samples is 334 ng•m^-3 with a range of 34.6—1 307 ng•m^-3, which is comparable to the downtown TSP samples of Yunlin in Taiwan reported and slightly lower than the level in 2002—2003 study. Two biomass burning episodes were caught by the levoglucosan measurements. By resorting to the meteorological satellite fire spot information and wind backward trajectories computed by HYSPLIT software, the episodes on Oct.6, 2005 and June 21, 2006 were attributed to the burnings of corn and wheat stalk in neighboring provinces, respectively. The biomass burning sources and air mass transportation routes are discussed as well.