文章基本信息

标题：Fingerprints of the urban particle number size distribution in Helsinki, Finland: Local versus regional characteristics
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作者：Tareq Hussein ; Bjarke Mølgaard ; Hanna Hannuniemi 等
期刊名称：Boreal Environment Research
印刷版ISSN：1239-6095
出版年度：2014
卷号：19
期号：1
页码：1-20
语种：English
出版社：Finnish Limnological Society
摘要：Understanding the fingerprints of urban aerosols is very important in urban model development. Cluster analysis combined with visual classification, air mass back-trajectories, and local meteorology form a comprehensive analysis tool to understand the fingerprints of urban aerosol particles and relate them to their source origin as local or regional. Here we identified seven fingerprints of urban aerosols in Helsinki during 2006. The fingerprints of fresh emissions (Clusters 1–2) from local sources including traffic are characterized by a dominant nucleation mode (GMD < 25 nm and 62%–82% of the submicron particle number concentration). Cluster 3 is characterized by aged ultrafine particle modes with a dominant Aitken mode (diameter 25–100 nm). The fingerprint (Cluster 0) of New Particle Formation (NPF) events is characterized by a second nucleation mode (GMD < 10 nm and a fraction more than 65% of the submicron particle number concentration); the inclusion of particles with Dp < 7 nm in the analysis is important to identify this unique fingerprint. The fingerprints (Clusters 4–5) of aerosols originated via Short-Range or Long-Range Transport (SRT/LRT) from Russia; middle Europe and the Baltic Sea are characterized by dominant Aitken and accumulation modes (as high as 70% of the submicron particle number concentration). Cluster 6 emerged from a mixture between locally emitted aerosols and those originated via SRT/LRT with roughly 50% contribution of the nucleation mode in the submicron particle number concentration. While the data used in this analysis were for the year 2006 only, we foresee the fingerprints are generally valid for the Helsinki Metropolitan Area.