南京市不同功能区大气降尘的沉降通量及污染特征

 选择南京市的钢铁工业区、工业与居民混合区、交通干道、居民生活区、风景区、城市郊区6种典型城市功能区,按月定期收集降尘,计算沉降通量.应用ICP-AES分析降尘中元素的含量,比较其化学组成和污染物特征.结果表明,研究期间南京市降尘沉降通量为3.39～65.95g/(m²·月),工业区降尘通量显著高于其他区域,说明其局部来源的贡献超过了区域背景;不同功能区降尘中地壳元素绝对含量均较高,为主要的成分,而一些污染元素(Cu、Zn、Pb、Ni、As)的含量在工业混合区和钢铁工业区则相对较高.降尘中Ca、Cu、Zn、Pb的富集系数均>10.北方远程来源的降尘对南京地区的影响很大,特别是对该地区的土壤“复钙”作用有很大的影响.

The flux and pollution character of dust-fall in different functional zones of Nanjing

Six typical functional zones: steel industrial zone, the mixed industrial and residential zone, the main traffic line, residential area, scenery zone and city suburb zone in Nanjing City were selected for monthly dust-fall collection. Dust deposition flux was calculated. The element content of dust was analyzed by ICP-AES. The dust flux of Nanjing city was 3.39~65.95g/(m2?month) during the study period. Dust-fall flux in steel industry zone was significantly higher than all other sites, indicating the local contribution of local source exceeded that of regional background. The absolute content of crustal elements in dust-fall of different zones were all higher, being the main component, but heavy metal elements such as Cu, Zn, Pb , Ni and As were relatively much higher in industrial zone and the mixed industrial and residential zone. The enrichment coefficients of Ca, Cu, Zn and Pb in dust-fall were all >10. The influence of dust-fall from remote north source on Nanjing was very great especially on calcium re-enrichment of surface soils.