ASTRA APART

Duration: 2006-2009

Contact: Nicolas Bukowiecki, nicolas.bukowiecki@psi.ch

Particle emissions of road traffic are generally associated with fresh exhaust emissions. However, the preceding research project ASTRA2000/415 as well as several recent studies identified a clear contribution of non-exhaust emissions to the traffic related PM10 load of the ambient air. These emissions consist of particles produced by abrasion from brakes, road wear, tire wear, as well as vehicle induced resuspension of deposited road dust. For many urban environments, quantitative information about the contributions of the individual abrasion processes is still scarce. For effective PM10 reduction scenarios it is of particular interest to know whether road wear, resuspension or fresh abrasion from vehicles dominates the non-exhaust PM10 emissions.

The main scope of the project APART (Abrasion PArticles produced by Road Traffic) was to identify and quantify the non-exhaust fraction of traffic related PM10 for several road-side locations with characteristic traffic regimes.

Specific goals

• To provide a reliable base for future PM10 reduction scenarios
• Determination of location-specific emission factors (mg/km/vehicle) for trace elements emitted by local road traffic.
• Calculation of location-specific emission factors (mg/km/vehicle) for individual non-exhaust emission sources.
• Separation of emission factor values for light duty vehicles (LDV) and heavy duty vehicles (HDV).
• Evaluation of the local mass contribution from individual non-exhaust sources (% of traffic related PM10).

• Zürich Kaserne, Switzerland, 2006-2008 (Urban background)
• Zürich Weststrasse, Switzerland, 2006-2008 (Urban traffic)
• Reiden, Switzerland, 2006-2008 (Freeway traffic)

• Mass contribution of non-exhaust sources: During the time periods considered for the measurements in the street canyon at Zürich-Weststrasse (February and March 2007) and along the national freeway A2 in Reiden LU (October and November 2007), the sum of direct abrasion sources and vehicle induced road dust resuspension made up 60% of the total traffic related PM10 emissions.
• Brake wear: Brake wear was characterized by a characteristic pattern of Fe, Cu, Zn, Mo, Zr, Sn, Sb and Ba, which is similar to real-world fleet emissions for brake wear reported in other studies. In contrast, the pattern of these elements in individual brake linings is extremely inhomogeneous. Compared to older studies, the measured emission factors for brake wear related lead (Pb) were considerably lower, indicating that lead has in the mean time largely been replaced in brake linings. At Zürich-Weststrasse, the heavily disturbed traffic flow resulted in brake wear emissions that made up 20% (15 mg/km/vehicle) of the total PM10 emissions from traffic. In contrast, brake wear emissions contributed less along the freeway in Reiden (3%, 3 mg/km/vehicle), due to the free-flowing traffic regime. For both locations the brake wear emissions from heavy duty vehicles were approximately 10 times higher than from light duty vehicles.
• Traffic induced resuspension of road dust: Generally, road dust resuspension is strongly influenced by available road dust and thus by the pollution of the road surface. In the street canyon at Zürich-Weststrasse, up to 40% of the traffic related PM10 emissions were assigned to resuspended road dust during the period of measurements in February and March 2007. Along the freeway in Reiden, the contribution of resuspended road dust to traffic related PM10 emissions was estimated to be higher than 50% in October and November 2007. In the heavily trafficked street canyon at Zürich-Weststrasse, the available dust on the surface was resuspended and kept in suspended state mainly by the turbulence induced by the heavy duty vehicles, leaving only small amounts of dust to be resuspended by the light duty vehicles.

• Dr. Robert Gehrig, Empa, Dübendorf, Switzerland
• Prof. Dr. Urs Baltensperger, PSI, Villigen, Switzerland

The project was funded by the Bundesamt für Strassen (ASTRA), grant no. ASTRA 2005/007.

Final Report

PM10-Emissionsfaktoren von Abriebspartikeln des Strassenverkehrs (APART) - PM10 emission factors of abrasion particles from road traffic.
Bukowiecki, N., R. Gehrig, P. Lienemann, M. Hill, R. Figi, B. Buchmann, M. Furger, A. Richard, C. Mohr, S. Weimer, A. Prévôt, and U. Baltensperger, 2009
Bundesamt für Strassen, Bern, 194 pp.
Download (16 Mb).

Journal Articles

Sources and variability of inhalable road dust particles in three European cities.
Amato, F., M. Pandolfi, T. Moreno, M. Furger, J. Pey, A. Alastuey, N. Bukowiecki, A. S. H. Prevot, U. Baltensperger, and X. Querol, 2011
Atmos. Environ., 45, 6777-6787.
DOI: 10.1016/j.atmosenv.2011.06.003

Size and time-resolved roadside enrichment of atmospheric particulate pollutants.
Amato, F., M. Viana, A. Richard, M. Furger, A. S. H. Prévôt, S. Nava, F. Lucarelli, N. Bukowiecki, A. Alastuey, C. Reche, T. Moreno, M. Pandolfi, J. Pey, and X. Querol, 2011
Atmos. Chem. Phys., 11, 2917-2931.
DOI: 10.5194/acp-11-2917-2011

Real-World Emission Factors for Antimony and Other Brake Wear Related Trace Elements: Size-Segregated Values for Light and Heavy Duty Vehicles.
Bukowiecki, N., P. Lienemann, M. Hill, R. Figi, A. Richard, M. Furger, K. Rickers, G. Falkenberg, Y. Zhao, S. S. Cliff, A. S. H. Prevot, U. Baltensperger, B. Buchmann, and R. Gehrig, 2009
Environmental Science & Technology, 43, 8072-8078.
DOI: doi: 10.1021/es9006096

PM10 emission factors for non-exhaust particles generated by road traffic in an urban street canyon and along a freeway in Switzerland.
Bukowiecki, N., P. Lienemann, M. Hill, M. Furger, A. Richard, F. Amato, A. S. H. Prévôt, U. Baltensperger, B. Buchmann, and R. Gehrig, 2010
Atmos. Environ., 44, 2330-2340.
DOI: 10.1016/j.atmosenv.2010.03.039

X-ray fluorescence spectrometry for high throughput analysis of atmospheric aerosol samples: The benefits of synchrotron X-rays.
Bukowiecki, N., P. Lienemann, C. N. Zwicky, M. Furger, A. Richard, G. Falkenberg, K. Rickers, D. Grolimund, C. Borca, M. Hill, R. Gehrig, and U. Baltensperger, 2008
Spectrochimica Acta Part B: Atomic Spectroscopy, 63, 929-938 doi:10.1016/j.sab.2008.05.006.
DOI: 10.1016/j.sab.2008.05.006

Deposition uniformity and particle size distribution of ambient aerosol collected with a rotating drum impactor.
Bukowiecki, N., A. Richard, M. Furger, E. Weingartner, M. Aguirre, T. Huthwelker, P. Lienemann, R. Gehrig, and U. Baltensperger, 2009
Aerosol Science and Technology, 43, 891-901.
DOI: 10.1080/02786820903002431

Mobile load simulators - A tool to distinguish between the emissions due to abrasion and resuspension of PM10 from road surfaces.
Gehrig, R., K. Zeyer, N. Bukowiecki, P. Lienemann, L. D. Poulikakos, M. Furger, and B. Buchmann, 2010
Atmos. Environ., 44, 4937-4943.
DOI: 10.1016/j.atmosenv.2011.06.003

Source apportionment of size and time resolved trace elements and organic aerosols from an urban courtyard site in Switzerland.
Richard, A., M. F. D. Gianini, C. Mohr, M. Furger, N. Bukowiecki, M. C. Minguillón, P. Lienemann, U. Flechsig, K. Appel, P. F. DeCarlo, M. F. Heringa, R. Chirico, U. Baltensperger, and A. S. H. Prévôt, 2011
Atmos. Chem. Phys., 11, 8945-8963.
DOI: 10.1016/j.atmosenv.2010.08.020