Measurements of particulate sugars at urban and forested suburban sites

Neutral sugars (arabinose, fucose, galactose, glucose, mannose, rhamnose, and xylose) in fine and coarse aerosols were measured at urban and forested suburban sites in Japan. The most dominant compound in the sugar group was glucose at both sites. Size partitioning of the sugars generally showed dominance in the fine mode range but shifted toward the coarse mode range in summer. Seasonal trends in the sugar concentrations in the fine and coarse mode ranges were opposite: higher concentrations of fine mode sugars were found in winter, although coarse mode sugars increased in summer. Fine mode glucose consisted dominantly of the combined form, whereas free glucose increased in the coarse mode range. Although the sources of the sugars in the aerosols remain largely uncertain, primary biogenic particles can be considered as candidates of main sources of the sugars in both coarse and fine mode ranges.