Dispersion of traffic-related exhaust particles near the Berlin urban motorway – estimation of fleet emission factors
Open Access
- 2 April 2009
- journal article
- research article
- Published by Copernicus GmbH in Atmospheric Chemistry and Physics
- Vol. 9 (7), 2355-2374
- https://doi.org/10.5194/acp-9-2355-2009
Abstract
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.This publication has 53 references indexed in Scilit:
- Comparison of average particle number emission factors for heavy and light duty vehicles derived from rolling chassis dynamometer and field studiesAtmospheric Environment, 2008
- Correlation between traffic density and particle size distribution in a street canyon and the dependence on wind directionAtmospheric Chemistry and Physics, 2006
- Long-term observation of real-world road traffic emission factors on a motorway in SwitzerlandAtmospheric Environment, 2006
- Aerosol and NOx emission factors and submicron particle number size distributions in two road tunnels with different traffic regimesAtmospheric Chemistry and Physics, 2006
- Atmospheric number size distributions of soot particles and estimation of emission factorsAtmospheric Chemistry and Physics, 2006
- Particulate size distributions and mass measured at a motorway during the BAB II campaignAtmospheric Environment, 2005
- Physical characterization of particulate emissions from diesel engines: a reviewJournal of Aerosol Science, 2005
- Evolution of particle number distribution near roadways. Part III: Traffic analysis and on-road size resolved particulate emission factorsAtmospheric Environment, 2005
- Modelling of the influence of aerosol processes for the dispersion of vehicular exhaust plumes in street environmentAtmospheric Environment, 2003
- Atmospheric particle number size distribution in central Europe: Statistical relations to air masses and meteorologyJournal of Geophysical Research: Atmospheres, 2001