Levoglucosan in Transboundary Biomass Burning Emissions in Southeast Asia

Liming Yang, Duc Minh Nguyen, LIYA E. YU

National University of Singappore

     Abstract Number: 483
     Last modified: January 25, 2010

Abstract
Levoglucosan (1,6-anhydro-beta-D-glucopyranose) can account for more than 15% of total organic carbons in aerosols emitting from biomass burning, and has been adopted as a fingerprint of biomass burning emission. However, several field observations and our laboratory kinetic studies show that levoglucosan can be substantially degraded, raising the needs to evaluate whether employing levoglucosan in receptor model is appropriate, and how degradation of levoglucosan may contribute to secondary organic aerosols. Singapore, located at the tip of Malaysia Peninsula, is often affected by transboundary pollution of biomass burning in Southeast Asia, which is accompanied by a surge of visit to hospital emergency room due to respiratory problems. To better understand impacts of transboundary emissions, PM2.5 were sampled during 08 September–05 October, 2008 when transboundary biomass burning aerosols substantially degraded air quality in Singapore. Results show that concentrations of levoglucosan were elevated during the episode although some levoglucosan could be contributed by local activities. An increase in dicarboxylic acids (DCAs) during the episode supports our previous mechanistic studies that levoglucosan is a precursor of abundant DCAs in emissions of biomass burning. Presence of 2,3-dihydroxy-propanoic acid in the collected particulate samples may further support the degradation of atmospheric levoglucosan for it has been identified as one of the intermediates generated from oxidation of levoglucosan. Additional implications of the temporal concentration trend in levoglucosan and its oxidation intermediates at the receptor site (Singapore) will also be discussed.