共 31 条
Variability of non-volatile fractions of atmospheric aerosol particles with traffic influence
被引:70
作者:
Wehner, B
Philippin, S
Wiedensohler, A
Scheer, V
Vogt, R
机构:
[1] Inst Tropospher Res, D-04318 Leipzig, Germany
[2] Ford Forschungzentrum Aachen, D-52072 Aachen, Germany
关键词:
volatility;
vehicle emissions;
D O I:
10.1016/j.atmosenv.2004.08.015
中图分类号:
X [环境科学、安全科学];
学科分类号:
08 ;
0830 ;
摘要:
Emissions from vehicular traffic are considered to be a major source of anthropogenic submicrometer particles in the urban environment. In this study, volatile and non-volatile number and volume fractions were distinguished in particles sampled for three consecutive days (Friday, Saturday, and Sunday) close to a highway (HW) (M) in Germany and for one day in the urban area of Aachen, Germany. A volatility tandem differential mobility analyzer (VTDMA) and a thermodenuder (TD) combined with two scanning mobility particle sizers (SMPS) were used to get insight into a size-resolved mixing state of volatile and non-volatile particle fractions. Operating the VTDMA at 280degreesC, the number size distribution of non-volatile particle cores was determined for initial particle sizes of 30, 50, 80, and 150 nm. The number size distributions from 10 to 400nm of ambient and non-volatile aerosol particles were measured by using parallel a SMPS and TD/SMPS combination, respectively. Number size distributions measured near the HW showed a bimodal size distribution with a maximum number concentration at particle sizes between 10 and 20 nm. The TD/SMPS results for the HW site revealed that the nucleation mode disappeared after heating (completely volatile) and in total 10-20% by number of traffic-related particles were non-volatile. The VTDMA results revealed that only 22% of the 30nm particles had a non-volatile core above the instrument detection limit of 10 nm. With increasing particle diameter, this non-volatile number fraction increased to ca. 60% for 50 nm particles and to approximately 100% for 80 and 150 nm particles. These findings mean that each particle in the upper Aitken and lower accumulation mode range contains a non-volatile core. With increasing traffic influence the number fraction of less-volatile particles representing mainly primary soot emissions increases to 62% for 50nm particles and 71% for 80nm particles. (C) 2004 Elsevier Ltd. All rights reserved.
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页码:6081 / 6090
页数:10
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