[Characteristics and Sources of Water Soluble Inorganic Ions in Fine Particulate Matter During Winter in Xuzhou].

A total of 32 daily PM _2.5 samples were collected from December 2016 to February 2017 in the urban area of Xuzhou city. Water-soluble inorganic ions (WSⅡs), including F ^- , Cl ^- , NO ₃ ^- , SO ₄ ^2- , Na ⁺ , Mg ²⁺ , NH ₄ ⁺ , K ⁺ and Ca ²⁺ , were determined by ion chromatography. The average mass concentration of PM _2.5 was (164.8±77.3) μg·m ^-3 and the average total mass concentration of the nine ions was (67.5±36.1) μg·m ^-3 , the contribution of the WSⅡs to the PM _2.5 was more than 40.9%. The order of the concentrations of individual ions was NO ₃ ^- > SO ₄ ^2- > NH ₄ ⁺ > Cl ^- > Ca ²⁺ > K ⁺ > Na ⁺ > Mg ²⁺ > F ^- . NH ₄ ⁺ , NO ₃ ^- , and SO ₄ ^2- (SNA) were the major components of the water-soluble ions in the PM _2.5 measurement. The average mass concentration of WSⅡs in clean air, mild haze, and severe haze was (12.8±8.8), (59.0±22.8) and (86.3±36.0) μg·m ^-3 , respectively. The contribution of SNA to WSⅡs was 86.4%, 82.8%, and 78.9%, respectively. The correlation between each component of SNA with each other was significant. NH ₄ ⁺ , NO ₃ ^- , and SO ₄ ^2- were in the form of (NH ₄ ) ₂ SO ₄ and NH ₄ NO ₃ . Secondary formation, biomass burning, fossil fuel combustion, and dust were the major sources of the water-soluble ions in PM _2.5 .