洛阳市不同功能区地表灰尘重金属的粒径分布特征

以洛阳市为例,分析了工业区、商业区、居民区、城乡结合处、城市绿地和城市主干道等不同功能区地表灰尘颗粒组成及重金属（Cu、Zn、Pb、Cd）粒级效应。结果表明：洛阳市不同功能区地表灰尘粒径分布具多峰性,分别在850~250、150~96及〈75μm出现分布峰值。不同功能区地表灰尘粒径差异显著,居民区和城市绿地细颗粒比重较大,工业区和城市主干道粗颗粒相对较多。各金属元素的质量分数粒级效应不一,Pb在工业区各粒级中质量分数最高,具粒级效应,其它功能区粒级效应不明显,Cd、Cu粒级效应明显,Cd富集更趋向于细粒（96~75和〈75μm）,Cu在180~150μm粒径质量分数迅速升高,并随着粒径减小,基本呈上升趋势,除工业区和城乡结合部外,其它功能区均在〈75μm粒径达到峰值。除居民区和城乡结合部各粒径Zn分布较平均外,Zn主要富集于180~150μm粒径颗粒,且质量分数明显高于其它各粒级,粒级效应基本呈现正态分布。

Particle size distribution of heavy metals in surface dusts from different functional zones of Luoyang city

Taking Luoyang City as an example,the particle composition and particle size distribution of heavy metals（Cu,Zn,Pb,Cd） in surface dusts were investigated in six different functional zones,i.e.,urban-rural continuum,urban artery,industrial district,urban green space,residential district,and business district.Results showed a multi-peak distribution of particle sizes of surface dusts in different functional zones,occurring at 850~250,150~96,and 75 μm,respectively.Particle size distribution differed in different functional zones,small size particles accounting for a high proportion in residential district and urban green space,while those with large size occurring mainly in industrial district and urban artery.Particle size distribution had different effects on the contents of different heavy metals.Pb occurred most highly in surface dusts from industrial district and showed particle size distribution only in this zone.Cd and Cu also showed particle size distribution,and Cd accumulated mainly in small size particles（96~75 and 75 μm）,while Cu content showed a negative correlation with particle size,and increased sharply in particles with size of 180~150 μm and reached highest in particles smaller than 75 μm in zones except industrial district and urban-rural continuum.Zn did not display particle size distribution in residential district and urban-rural continuum,while accumulated much highly in particles with size of 180~150 μm than in other size particles in other four zones,showing a normal distribution in different size particles.