无锡市区环境空气中PM10来源解析

Source Apportionment of Ambient PM_(10) in Urban Area of Wuxi City

于2005年采集了无锡市区PM10源和受体样品,并测定了无机元素、水溶性离子和碳等组分的含量.采用OC/EC〔即ρ(OC)/ρ(EC)〕最小比值法确定了二次有机碳(Secondary Organic Carbon)对PM10的贡献,并据此重新构建了受体化学成分谱,使用化学质量平衡受体模型(CMB)和二重源解析技术对无锡市区的PM10来源进行了解析.结果表明:城市扬尘是无锡市环境空气中PM10的主要来源,其分担率达50.49%;煤烟尘和机动车尾气尘的分担率也分别为13.97%和7.80%;其他重要源类按分担率依次为二次有机碳,SO42-,建筑水泥尘,NO3-,土壤尘和钢铁尘等,其中二次有机碳年贡献值为6.94μg/m3,年分担率为6.18%.

Samples from both ambient particulate matter （PM10） and PM10 sources were collected in Wuxi City in 2005. Their inorganic elements, water-solvent ions and carbon species were analyzed to identify the sources of PM10. Contribution of secondary organic carbon （SOC） to PM10 was determined by the ＂OC/EC minimum ratio＂ technique, and the chemical profiles of sources and ambient PM10 were established. Sources of PM10 in Wuxi City were analyzed based on the chemical mass balance （CMB） receptor model and nested chemical mass balance （NCMB）. The results showed that suspended dust was the most important PM10 source with a contribution of 50.49% ; flying ash from coal combustion and vehicle exhaust were also important sources with contributions of 13.97% and 7.80%, respectively. Sources like SOC, SO4^2- , construction cement dust, NO3^- , soil dust and Ferrous dust were all significant contributive sources to ambient PM10. The annual average SOC concentration was 6.94μg/m^3 , accounting for 6.18% of the total mass in ambient PM10.