Characteristics of aerosol during major biomass burning events over eastern central India in winter: A tracer-based approach

Abstract

Size-segregated aerosol samples collected from a rural site (Rajim: 20˚59′N and 81˚55′E) in eastern central India during the winter of 2011 were analyzed for anhydrosugars, sugar alcohols and primary sugars to better understand their potential sources and formation. Anhydrosugars showed the predominance of levoglucosan, whereas sugar alcohol showed the predominance of mannitol, with glucose as a major primary sugar in the sub-micron (Da < 1.1 μm) and super-micron mode (Da > 1.1 μm). Levoglucosan gave a bimodal size distribution pattern with a major peak at 0.43–0.65 μm in the sub-micron mode during period 2 and period 3, suggesting its origin from biomass burning, whereas during period 1 the major peak was found at 4.4–5.8 μm in super-micron mode that may be due to the mixing of biomass burning derived particles with soil dust particles. Sugar alcohols (arabitol and mannitol) and primary sugars (glucose and trehalose) showed bimodal size distribution trend with a major peak at 4.4–5.8 μm in super-micron mode during all periods, perhaps due to fungal activity and soil dust re-suspension, respectively. The potential ingress of biomass burning derived particles into the lungs was calculated to be high whereas fungal spores and soil particles were more likely found in the upper respiratory tract. Principal component analysis and correlation analysis showed that biomass burning was a major source in the sub-micron mode whereas fungal spores and vegetative soil were dominant sources for quantified sugars in super-micron mode.