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Titel |
Dispersion of traffic-related exhaust particles near the Berlin urban motorway – estimation of fleet emission factors |
VerfasserIn |
W. Birmili, B. Alaviippola, D. Hinneburg, O. Knoth, T. Tuch, J. Borken-Kleefeld, A. Schacht |
Medientyp |
Artikel
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Sprache |
Englisch
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ISSN |
1680-7316
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Digitales Dokument |
URL |
Erschienen |
In: Atmospheric Chemistry and Physics ; 9, no. 7 ; Nr. 9, no. 7 (2009-04-02), S.2355-2374 |
Datensatznummer |
250007155
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Publikation (Nr.) |
copernicus.org/acp-9-2355-2009.pdf |
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Zusammenfassung |
Atmospheric particle number size distributions of airborne particles (diameter range 10–500 nm)
were collected over ten weeks at three sites in the vicinity of the A100 urban motorway in Berlin,
Germany. The A100 carries about 180 000 vehicles on a weekday. The roadside particle distributions
showed a number maximum between 20 and 60 nm clearly related to the motorway emissions. The
average total number concentration at roadside was 28 000 cm−3 with a total range of
1200–168 000 cm−3. At distances of 80 and 400 m from the motorway the concentrations
decreased to mean levels of 11 000 and 9000 cm−3, respectively. An obstacle-resolving
dispersion model was applied to simulate the 3-D flow field and traffic tracer transport in the
urban environment around the motorway. By inverse modelling, vehicle emission factors were derived
that are representative of a fleet with a relative share of 6% lorry-like vehicles, and driving at
a speed of 80 km h−1. Three different calculation approaches were compared, which differ in
the choice of the experimental winds driving the flow simulation. The average emission factor per
vehicle was 2.1 (±0.2) · 1014 km−1 for particle number and 0.077
(±0.01) · 1014 cm3 km−1 for particle volume. Regression analysis
suggested that lorry-like vehicles emit 123 (±28) times more particle number than passenger
car-like vehicles, and lorry-like vehicles account for about 91% of particulate number emissions
on weekdays. Our work highlights the increasing applicability of 3-D flow models in urban
microscale environments and their usefulness for determining traffic emission factors. |
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