道路降尘PM2.5水溶性离子特征研究

Analysis on Water-soluble Ions in Urban Road Dust PM2.5

为探究秋季城市道路降尘PM2.5中水溶性离子污染特征及来源,收集石家庄市道路降尘PM2.5样品,运用相关性及比值法分析10种水溶性离子的污染特征,结果表明:Ca^2+浓度最高,SO4^2-次之,F^-浓度最低;快速路中离子浓度最高,各种离子在不同类型道路中污染特征不同;阳离子易在1.5米处富集,而SO4^2-、Cl^-和F^-在2.5米处富集。阴阳离子平衡分析显示颗粒物呈碱性,且2.5米处碱性更强。NO-3/SO4^2-平均值为0.18,固定源影响大于移动源,水溶性离子主要来源为:道路扬尘、建筑尘的沉降、工业燃烧排放、机动车尾气排放及燃煤排放。

To explore the characteristics and sources of water-soluble ion components in urban road dust PM2.5, 4 different saples types of road dust in Shijiazhuang were collected, and the pollution characteristics of 10 water-soluble ions were analyzed by correlation analysis and ratio method. Results showed that the concentration of Ca^2+ was the highest, followed by SO4^2- and F^- was the lowest concentration. The concentration of various ions in expressway was relatively high, and various ions showed different trends in different road types. However, the concentration of ions varies significantly at different heights. Positive ions tend to be enriched at 1.5 m, while the concentration of SO4^2-, Cl^- and F^- was relatively high at 2.5 m. The results of pH balance analysis showed that the particles were alkaline and more alkaline at 2.5 m than that at 1.5 m high. Average value of NO-3/SO4^2- was 0.18, which indicated that the influence from fixed sources was greater than that of mobile sources, the main sources of water-soluble ions were:road dust, settlement of building dust, industrial combustion emissions, vehicle exhaust emissions and coal burning emissions.