【摘要】 为探究长沙市秋季PM_2.5水溶性无机离子组成特征和来源,于2017年9月～11月在长沙城区连续采集大气颗粒物PM_2.5样品共85个,并用离子色谱仪分析样品中的9种水溶性无机离子(F^-、Cl^-、NO₃^-、SO₄^2-、K⁺、Na⁺、Ca²⁺、Mg²⁺、NH₄⁺)。结果表明,长沙市秋季PM_2.5质量浓度的平均值为56. 3±39. 6μg/m³,总水溶性无机离子质量浓度平均值为29. 47±19. 10μg/m³,占PM_2.5的52. 3%,其中NO₃^-、SO₄^2-、NH₄⁺是PM_2.5中最主要的离子成分。霾天PM_2.5平均质量浓度约是清洁天的3倍,NO₃^-、NH₄⁺、K⁺、Cl^-四种离子的快速增长对霾天PM_2.5中离子的贡献最大。由PMF模型解析可知,秋季大气PM_2.5主要来源于机动车尾气和燃煤源,而扬尘、生物质燃烧源、工业源和海盐的贡献不到30%。长沙市秋季大气污染呈现机动车尾气等移动源和燃煤等固定源的混合型污染为主。更多还原

【Abstract】 To research the characteristics and sources of water-soluble inorganic ions in PM_2.5 during autumn,in Changsha city,85 samples of PM_2.5 were collected from September to November 2017,and 9 kinds of water-soluble inorganic ions( F^-,Cl^-,NO₃^-,SO₄^2-,K⁺,Na⁺,Ca²⁺,Mg²⁺ and NH₄⁺) in the samples were analyzed by the ion chromatograph. The results showed that the average mass concentration of PM_2.5 in autumn in Changsha city was 56. 3±39. 6 μg/m³,and the total mass concentration of water-soluble inorganic ions was average 29. 47±19. 10 μg/m3,accounting for 52. 3% of PM_2.5,in which NO₃^-,SO₄^2- and NH₄⁺ were major ionic compositions.The average mass concentration of PM_2.5 was about 3 times during the hazy days than that during the clean days,and the fast growing concentrations of NO₃^-、NH₄⁺、K⁺ and Cl^- were principal contributors to the ions of PM_2.5. Based on positive matrix factorization（ PMF）,it was found that the water-soluble inorganic ions in PM_2.5 during autumn mainly came from vehicle exhaust and coal combustion,while flying dust,biomass burning,industrial sources and sea salt also contribute to less than 30% of these ions. The air pollution during autumn in Changsha city was the mixture of movable sources as vehicle exhaust and fixed sources as coal combustion.更多还原