摘要：于2012年5月,采集316国道黄石-武汉段沿线大气降尘样品29个,采用离子色谱仪对样品中10种水溶性离子(NH₄⁺，K⁺ ，Mg²⁺，Ca²⁺，F^- ，Cl^- ，Br^- ，NO₂^- ，NO₃^- ，SO4^2-)的含量进行分析。结果表明:该路段降尘中水溶性离子主要为Ca²⁺、Cl^-、NO₃^-、SO₄^2-,质量分数由大到小的顺序为SO₄^2-、Ca²⁺、NO₃^-、Cl^-,且NH₄⁺、K⁺、Mg²⁺、Ca²⁺、F^-、Cl^-、NO₃^-、SO₄^2-均存在局部污染;NO3-与SO42-的质量比均值为0.06;阴阳离子平衡方程计算表明,降尘样品呈偏酸性;相关性和主成分分析表明,SO4^2-与Ca²⁺、Mg²⁺的相关性显著,相关系数分别达到0.997、0.957;水溶性离子主要来源于城市易散性粉尘或粉尘陆地源及燃煤,也可能有生物质及其他化石燃料的燃烧等人为源影响。

关键词：316国道；降尘；水溶性离子；污染特征

Abstract： There were 29 dustfall samples collected from the section of Huangshi to Wuhan of the National Highway No.316 during May 2012. The mass fractions of water soluble ions （NH₄⁺，K⁺，Mg²⁺，Ca²⁺，F^-，Cl^-，Br^-，NO₂^-，NO₃^-，SO₄2-）in the samples were determined by ion chromatography. The results show that Ca²⁺、Cl^-、NO₃^- and SO₄^2- are the major ionic composition in the dustfall samples. The order of mass fraction is SO₄^2-， Ca²⁺， NO₃^-， Cl^- . NH₄⁺， K⁺， Mg²⁺， Ca²⁺， F^-， Cl^-， NO₃^- and SO₄^2- are presented local pollution. The mean mass fraction ratio of NO₃^- and SO₄^2- is 0.06. The results from ion balance calculation analysis suggest that the dustfall samples are weak acidic. Through the correlational analysis and principal component analysis， Ca²⁺， Mg²⁺ and SO₄^2-show a positive correlation， and the correlative coefficients are 0.997 and 0.956， respectively. The major sources of dustfall are characterized as urban dust and land surface dust， followed by transportation exhaust and fossil fuel combustion． 

Keywords: the National Highway No. 316; dustfall; water soluble ion; pollution characteristic