Seasonal and Diurnal Variation of PM2.5 Apparent Particle Density in Urban Air in Augsburg, Germany

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• 作者：Mike Pitz ; Otmar Schmid ; Joachim Heinrich ; Wolfram Birmili ; Jü ; rgen Maguhn ; Ralf Zimmermann ; H.-Erich Wichmann ; Annette Peters ; Josef Cyrys
• 刊名：Environmental Science & Technology
• 出版年：2008
• 出版时间：July 15, 2008
• 年：2008
• 卷：42
• 期：14
• 页码：5087 - 5093
• 全文大小：637K
• 年卷期：v.42,no.14(July 15, 2008)
• ISSN：1520-5851

文摘

The apparent particle density of particulate matter with aerodynamic diameter <2.5 µm (ρ_2.5) was determined at an urban site in Augsburg, Germany and its correlation with chemical composition and meteorological conditions was investigated. ρ_2.5 showed strong day-to-day variation from 1.05 to 2.36 g cm⁻³ (5 to 95% percentile), and nearly 64% of the daily variability could be explained by a multiple variable regression model. A minimum in the morning and afternoon (about 1.5 g cm⁻³), and a maximum (near 1.8 g cm⁻³) during midday was observed. The minima represent fresh primary aerosol emissions, which were related to traffic soot particles with low density due to their agglomerate structure, especially observed in the early morning hours of weekdays. The maximum is likely due to increased secondary particle production and the presence of more aged particles with the built-up of the convectively mixed boundary layer. ρ_2.5 has the potential to serve as a crude tracer for chemical composition and atmospheric processing and might play an important role when considering the associations between health effects and ambient particles.