【摘要】 水溶性无机离子是PM_2.5的主要组分之一,对研究PM_2.5的物理化学性质,来源及其形成机理具有重要意义.本研究于2017年9月—2017年11月期间在贵阳城区采集了80个PM_2.5样品,并测定了8种水溶性离子浓度,探讨贵阳秋季PM_2.5水溶性离子组成特征及来源.结果表明贵阳秋季PM_2.5中无机离子的平均质量浓度为15.99μg·m^-3,阴离子和阳离子的平均质量浓度分别为10. 90μg·m^-3、5. 09μg·m^-3; SO₄^2-(8. 53±4.63μg·m^-3)平均质量浓度最高,其次是NH₄⁺(2.56±1.62μg·m^-3)、NO₃^-(2.21±2.96μg·m^-3)、Ca²⁺(1.98±0.88μg·m^-3),最后依次是K⁺(0.37±0.24μg·m^-3)、Cl-(0.16±0.11μg·m^-3)、Mg²⁺(0.11±0.03μg·m^-3)、Na⁺(0.07±0.06μg·m^-3); NH₄⁺、SO₄^2-、NO₃^-是主要水溶性离子,所占比例为83%; NO₃^-/SO₄^2-值平均为0.21±0.12,远小于1,说明贵阳秋季PM_2.5以固定源污染为主.相关性分析表明,PM_2.5中NH₄⁺主要以（NH₄）₂SO₄、NH₄HSO₄、NH₄NO₃的形式存在,Ca²⁺与Mg²⁺来源可能相同.结合富集系数分析NO₃^-、SO₄^2-、Ca²⁺、K⁺、Mg²⁺基本都是来源于陆源贡献,NO₃^-、SO₄^2-是人为源,Ca²⁺、K⁺、Mg²⁺是地壳源,此外Mg²⁺还有一部分海源贡献.更多还原

【Abstract】 Composition analysis of water-soluble ions（ WSIs） in fine particulate aerosol is of great significance for understanding the physical and chemical characteristics,sources and formation mechanism of PM_2.5. In the present study,a total of eighty PM_2.5 samples were collected in Guiyang urban area from September to November, 2017. Eight water-soluble ions were deterained to investigate the composition and sources of PM_2.5 water-soluble ions during autumn in Guiyang.Results showed that the average concentration of inorganic ions was 15. 99 μg·m^-3,while the averaged mass concentrations of anions and cations were respectively 10. 90 μg·m^-3 and 5.09 μg·m^-3. Among the interested ionic species,SO₄^2-( 8. 53 ± 4. 63 μg·m^-3) was the highest,followed by NH₄⁺( 2.56±1.62 μg·m^-3),NO₃^-( 2.21±2.96 μg·m^-3) and Ca²⁺( 1.98±0.88 μg·m^-3),while other ions ranked as K⁺( 0. 37 ± 0. 24 μg·m^-3),Cl-( 0. 16 ± 0. 11 μg·m^-3),Mg²⁺ ( 0. 11 ±0.03 μg·m^-3) 、Na⁺( 0.07±0.06 μg·m^-3). In general,NH₄⁺,SO₄^2- and NO₃^- were the main watersoluble ions,accounting for 83% of total inorganic ions. The ratio of NO₃^-/SO₄^2-（ 0.21±0.12） was much lower than unit,indicating that Guiyang PM_2.5 mainly suffered stationary source pollution during the sampling time. The correlation analysis showed that most of NH₄⁺ existed in the form of（NH₄）₂SO₄,NH₄HSO₄ and NH₄NO₃ in PM_2.5. Enrichment factor analysis relative to seawater and soil indicated that NO₃^-,SO₄^2-,Ca²⁺,K⁺,and Mg²⁺ were basically derived from terrestrial sources,while SO₄^2- and NO₃^- were from the anthropogenic source,Ca²⁺,K⁺,and Mg²⁺ mainly from crustal sources,a part of Mg²⁺ was from the sea source.更多还原