宁波市环境空气中PM_(10)和PM_(2.5)来源解析

Source Apportionment of Ambient PM_(10) and PM_(2.5) in Urban Area of Ningbo City

2010年在宁波3个环境受体点采集不同季节的PM10和PM2.5样品,同时采集颗粒物源类样品,分析它们的质量浓度及多种无机元素、水溶性离子和碳等组分的含量.采用OC/EC最小比值法确定了SOC(二次有机碳)对PM10和PM2.5的贡献,据此重新构建了受体化学成分谱.使用化学质量平衡模型对宁波市区的PM10和PM2.5来源进行了解析.结果表明:城市扬尘、煤烟尘、二次硫酸盐和机动车尾气尘是环境空气中PM10的主要来源,其分担率分别为23.0%、15.9%、13.3%和12.3%;对PM2.5有重要贡献的源类是城市扬尘、煤烟尘、二次硫酸盐、机动车尾气尘、二次硝酸盐和SOC,其分担率分别为19.9%、14.4%、16.9%、15.2%、9.78%和8.85%.

Samples of PM10 and PM2.5 and sources of particulate matter were collected in 2010 at three sites in Ningbo City,Zhejiang Province.Their inorganic elements,water solvent ions and carbon species were analyzed to identify the sources of the PM10 and PM2.5.The contributions of secondary organic carbon（SOC） to PM10 and PM2.5 were determined by the ＂OC/EC minimum ratio＂ technique,and the chemical profiles of ambient PM10 and PM2.5 were established.The sources of PM10 and PM2.5 in Ningbo City were analyzed based on the chemical mass balance（CMB） receptor model.The results showed：1） suspended dust,fly ash from coal combustion,sulfate and vehicle exhaust were the important sources of PM10,with contributions of 23.0%,15.9%,13.3% and 12.3%,respectively;2） the most important PM2.5 sources were suspended dust,fly ash from coal combustion,sulfates,vehicle exhaust,nitrates and SOC,with contributions of 19.9%,14.4%,16.9%,15.2%,9.78% and 8.85%,respectively.