杭州市超细微粒数浓度和粒径分布特征

应用FMPS(fast mobility particle sizer)对杭州市城区和城郊工业园区超细微粒的数浓度及粒径分布进行现场跟踪测量,并对数据进行分析.结果表明:杭州市大气超细微粒在5～500 nm内,主要呈对数双峰分布,峰值粒径多处在10～50 nm间.城郊工业园区的平均总数浓度最高,达4.11×104 cm-3,最高值出现在中午,而城区的峰值粒径区间整体右移,表明超细微粒污染较轻.超细微粒数浓度在上午和下午的上、下班期间出现不同程度上升,夜间浓度普遍降低,但偶有波动.部分工厂有夜间工作情况,故夜晚空气质量的下降也应引起重视. 

Number Concentration Spectrum and Size Distribution of Atmospheric Ultrafine Particles in Hangzhou City

The number concentration and size distribution of ultrafine particles(UFPs) in urban areas and suburban industrial areas of Hangzhou City,Zhejiang Province were tested using FMPS(fast mobility particle sizer).The results showed that in the range of 5 to 500 nm,the atmospheric particles mainly showed a logarithmic bi-modal distribution,with most CMD(count median diameter) from 10 to 50 nm.The highest average number concentration was 4.11×104 cm-3,found in the suburban industrial areas,and the peak concentration was detected at noon.The UFPs pollution in the urban areas was relatively light.The diurnal variation of the number concentration of UFPs illustrated that it was high during rush hours and generally lower at night,although fluctuations occurred occasionally.Some factories worked overnight,so sufficient attention should still be paid to the air quality at night.