Levoglucosan as a tracer of biomass burning: Recent progress and perspectives

Biomass burning (BB) is a major source of air pollution from local to global scale, having variable effects on air quality, human health, and climate system. Therefore, the source identification and characterization of BB derived aerosols and tracer gases in the ambient environment is crucial. This review provides recent updates on the applicability of levoglucosan as a BB tracer in different environmental matrices such as aerosols, marine, snow and ice-cores etc. Among several tracer of BB emissions, levoglucosan has recently received widespread attention due to its unique origin solely from the pyrolysis of cellulose and hemicellulose, making it as a robust marker for characterization and quantification of BB throughout the world. This review first summarizes the established and emerging analytical methods, and their advantages and disadvantages for measurement of levoglucosan. Second, we discuss the formation mechanism, lifetime and its stability in different environmental conditions. In addition, we also try to deliberate on the application of ratios of levoglucosan with different organic components such as mannosan (M) and organic carbon (OC) for better identification of emission sources. Spatial distributions of levoglucosan in different locations (e.g., urban, rural, forest, marine, poles and higher altitude) are discussed scrupulously and meticulously on a global scale. We also reviewed the distributions of levoglucosan in snow, ice core and sediments to understand its applicability to construct paleofire records. Finally, we propose some key recommendations for future work in different ambient environmental conditions by utilizing the ratios of levoglucosan with other compounds (not limited only to M and OC) and the use of levoglucosan to reconstruct the paleo-historical records of fire-activity.