Size distribution of sulfur species in fine and ultrafine aerosol particles using sulfur<i>K</i>-edge XANES

The sulfur species existing in different size aerosol particles were determined based on the 'white line' energy shift and the features of post edge structure of sulfur K-edge XANES (X-ray Absorption Near Edge Structure). The results indicated that sulfates were dominant sulfur species in aerosol particles. However, small amount of reductive sulfur species were also found in the ultrafine aerosol particles(<0.1 μm). Sulfates in aerosols mostly exhibited as (NH4)2SO4 and gypsum. Most (NH4)2SO4 distributed in aerosol particles finer than 0.952 μm, while gypsum was the dominant sulfate in coarse aerosols.