[Characteristics of the Size Distribution of Water Soluble Inorganic Ions in Sanya, Hainan].

Size-resolved filter samples were collected in Sanya every other week from June 2012 to May 2014. The mass concentrations of water-soluble inorganic ions, including anions (Cl, NO, SO) and cations (Na, NH, K, Mg, Ca) were measured by ion chromatography. The results showed that the total concentrations of measured water-soluble inorganic ions were (8.91±7.27) and (11.34±9.37) μg·m in PM and PM, respectively. In PM, SO and NH comprised 72.2% of all water-soluble inorganic ions, while in PM, Cl, Ca and Na comprised 67.6% of all water-soluble inorganic ions. In PM, the total concentrations of water-soluble inorganic ions had highest concentrations in winter and lowest concentrations in summer. In PM, the total concentrations of water-soluble inorganic ions presented the highest concentrations in summer. SO and NH showed bimodal size distributions and the peaks in the fine mode shifted from 0.43-0.65 μm in spring, summer and autumn to 0.65-1.1 μm in winter. NO, Na, Cl, Ca and Mg were unimodal with the peaks in the coarse mode of 4.7-9.0 μm. K showed bimodal size distribution with the fine mode at 0.43-0.65 μm and the coarse mode at 4.7-5.8 μm. PCA analysis showed that water-soluble inorganic ions were mainly affected by the secondary formation, sea salt and soil particles or falling dust.