Measurements of the total sugars in ambient aerosols by a phenol-sulfuric acid method

Abstract In order to characterize the composition of the water-soluble organic carbon (WSOC) in aerosols, the total sugars (TS) in the water-soluble fraction of the aerosols were measured by a phenol-sulfuric acid (PS) method. The TS measured by the PS method can be considered as the sum of the primary sugars and anhydrosugars, and explain about 20% and 11% of the WSOC in the coarse-mode and fine-mode aerosols, respectively. The TS in the coarse-mode aerosols showed a clear seasonal trend with higher concentrations in the summer and lower in the winter and would be mainly derived from plant debris and the associated substances. The seasonal trend in the concentrations of the TS in the fine-mode aerosols was unclear, but relatively higher in the winter and spring and lower from the late summer to early autumn. Biomass burning would be an important source of the fine-mode TS. The TS were mainly partitioned into the fine-mode aerosols especially in the winter; about 90% or more of the TS was partitioned into the fine-mode aerosols in the winter. On the other hand, the partitioning of the TS into the coarse-mode aerosols was enhanced in the summer. Biomass burning particles and plant debris would be important sources of the TS in the aerosols in the winter and summer, respectively. During the winter, the contribution of the TS to the WSOC in the aerosols was enhanced to 20% due to the impact of the biomass burning.