Speciation and distribution of sulfur in size-fractionated particulate matters in industrial district of Shanghai.

Airborne particles were collected at industrial district and suburban area in Shanghai using a 13-stage Dekati low pressure impactor covering a size range from 28nm to 9.92μm.Synchrotron radiation techniques of X-ray absorption near-edge structure spectroscopy(XANES) and X-ray fluorescence spectrometry(XRF) were employed.Sulfate was the dominant form of sulfur in both coarse and fine particles.In addition, a small amount of sulfur was also present as metal sulfide and thiophenic forms in ultrafine particles.Mass concentration of sulfur in fine particle was higher than that in coarse particle, and it constituted up to 70% of the total sulfur.Size distribution of sulfur in particle from industrial district showed multimode:ultrafine particle mode with peak at 0.091～0.154μm, accumulation mode with the peak at 0.38～0.611μm, and two coarse particulate modes with peaks at 1.59～3.98μm and 6.57～9.92μm.In contrast, ultrafine particle mode was not present in particles from suburb area, and two sub-modes of fine particles could be observed:condensation mode with the peak at 0.261～0.380μm and droplet mode with the peak at 0.611～0.945μm.Moreover, coarse particulate mode had a peak at 2.38～6.57μm.Differences in sulfur mass distribution of particles between industrial district and suburb could be attributed to local and regional sources, weather conditions, formation and conversion mechanisms of particles.Contribution of the sea to particles in industrial district was greater than that in suburb.