کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
6337354 | 1620351 | 2015 | 11 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Diurnal and seasonal variation of the PM2.5 apparent particle density in Beijing, China
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
علوم زمین و سیارات
علم هواشناسی
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چکیده انگلیسی
To characterize the features of particle apparent density and its correlation with chemical composition and meteorological conditions, continuous measurements of particle number size distributions and particle mass concentrations were conducted in the winter and summer periods in Beijing using a Scanning Mobility Particle Sizer and a Tapered Element Oscillating Microbalance with a Filter Dynamic Measurement System. The apparent density, as determined by the particle mass to volume ratios, showed strong seasonal and diurnal variations, with higher values were observed during the warm season (1.60 ± 0.43 g cmâ3, July to September 2014) compared to the cold season (1.41 ± 0.40 g cmâ3, November 2013 to January 2014). A minimum in the morning and afternoon rush hours was observed in both seasons, representing fresh primary aerosol emissions, which were related to soot particles with low density due to their agglomerate structure, especially observed in the late afternoon hours of the cold season (approximately 1.3 g cmâ3) when traffic emissions combined with the coal combustion for heating supply. The highest values were found during midday (approximately 1.8 g cmâ3) in the warm season, likely due to increased secondary particle production and the presence of more aged particles with a build-up of the convectively mixed boundary layer. The apparent particle density 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.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Atmospheric Environment - Volume 120, November 2015, Pages 328-338
Journal: Atmospheric Environment - Volume 120, November 2015, Pages 328-338
نویسندگان
Zirui Liu, Bo Hu, Dongsheng Ji, Yonghong Wang, Mingxing Wang, Yuesi Wang,