Abstract：Size-segregated aerosol samples were collected from January to December in 2008 at a Qingdao coastal site to investigate the sources and environmental effects of the water-soluble ions in the particles. Concentrations of major water-soluble inorganic ions in different size bins were analyzed using ion chromatography. The results showed that NH4+, K+, Cl-, NO3-, PO43-, and SO42- dominantly existed in the fine particles (aerodynamic diameters less than 2.1μm), while Na+, Mg2+, Ca2+, and F- were mainly presented in the coarse particles (aerodynamic diameters larger than 2.1μm) . The size distributions of ions showed obviously seasonal variations. NH4+, K+ and SO42- mainly existed in the fine particles all the year around, while Mg2+ and Ca2+ mainly existed in the coarse particles with a peak in the size-bin of 3.3~4.7μm. Na+ was mainly found in the coarse particles in spring, summer and autumn, but in the fine particles and had a concentration peak in the size-bin of 0.43~0.65μm in winter. Cl- peaked in the coarse particles with the peak in the size-bin of 2.1~3.3μm in spring while in the fine particles in other three seasons. NO3- was almost equally distributed in the fine and coarse particles in spring and summer, while showed a single peak in the accumulation mode in autumn and winter. PO43- was largely distributed in the coarse particles with a predominant peak in the coarse mode of larger than 11μm and a secondary peak in the fine mode of 0.65~1.1μm in summer, but it was mainly found in the fine particles in spring, autumn and winter. F- mainly existed in the coarse particles in spring and was equally distributed in the fine and coarse particles in autumn and winter. Coal combustion had a great effect on the size distributions of water-soluble ions. Both K+ and NH4+ reached peaks in 0.43~0.65μm during both the heating and non-heating periods. The size distribution of F- was bimodal, with one peak in 0.43~0.65μm and the other in 3.3~4.7μm during the heating period. Peak concentrations of Cl- appeared in the size range of 0.43~0.65μm during the heating period and 2.1~3.3μm during the non-heating period. Both SO42- and NO3- were bimodal during the heating and non-heating periods, with peak concentrations in 0.43~0.65μm and 3.3~4.7μm. The maximum concentrations of PO43- existed in 0.43~0.65μm during the heating period whilst in 3.3~4.7μm during the non-heating period.
