Abstract:

The investigation of PM2.5 aerosols using a portable mini-volume sampler was conducted between May 22 and September 22, 2006, in high-tech zone, Xi’an. Meantime NH3 gases were also sampled using passive Ogawa sampler. Water soluble ions (WSI) and NH3 concentrations were analyzed using an ion chromatogram (IC) analyzer. Integrating these data with SO2 and NO2 concentrations, the characteristics and sources of WSI of PM2.5 in spring and summer in Xi’an were studied. The results indicated that WSI in spring and summer was mainly composed of SO42-, NO3- and NH4+, accounting for 21.68%, 7.52% and 5.62% in mass, respectively, and the PM2.5 in spring and summer in XI’an were generally acidic. SO2 concentrations were poorly correlated with SO42-, NO3- and NO2, indicating that sulfate, nitrite, and ammonium in Xi’an are of different origins.

Key words: Xi’an, Water soluble ion, gases.