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Boundary-Layer Meteorology

, Volume 131, Issue 1, pp 19–34 | Cite as

On the Impact of Trees on Dispersion Processes of Traffic Emissions in Street Canyons

  • Christof Gromke
  • Bodo Ruck
Original Paper

Abstract

Wind-tunnel studies of dispersion processes of traffic exhaust in urban street canyons with tree planting were performed and tracer gas concentrations using electron capture detection (ECD) and flow fields using laser Doppler velocimetry (LDV) were measured. It was found that tree planting reduces the air exchange between street canyons and the ambience. In comparison to treeless street canyons, higher overall pollutant concentrations and lower flow velocities were measured. In particular, for perpendicular approaching wind, markedly higher concentrations at the leeward canyon wall and slightly lower concentrations at the windward canyon wall were observed. Furthermore, a new approach is suggested to model porous vegetative structures such as tree crowns for small-scale wind-tunnel applications. The approach is based on creating different model tree crown porosities by incorporating a certain amount of wadding material into a specified volume. A significant influence of the crown porosity on pollutant concentrations was found for high degrees of porosity, however, when it falls below a certain threshold, no further changes in pollutant concentrations were observed.

Keywords

Model trees Pollutant dispersion Porosity Street canyon Wind tunnel 

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References

  1. Ahmad K, Khare M, Chaudhry KK (2005) Wind tunnel simulation studies on dispersion at urban street canyons and intersections—a review. J Wind Eng Ind Aerodyn 93: 697–717. doi: 10.1016/j.jweia.2005.04.002 CrossRefGoogle Scholar
  2. Baik J, Kim J (2002) On the escape of pollutants from urban street canyons. Atmos Environ 36: 527–536. doi: 10.1016/S1352-2310(01)00438-1 CrossRefGoogle Scholar
  3. Chang C, Meroney RN (2003) Concentration and flow distributions in urban street canyons: wind tunnel and computational data. J Wind Eng Ind Aerodyn 91: 1141–1154. doi: 10.1016/S0167-6105(03)00056-4 CrossRefGoogle Scholar
  4. DePaul FT, Sheih CM (1985) A tracer study of dispersion in an urban street canyon. Atmos Environ (1967) 19:555–559Google Scholar
  5. DePaul FT, Sheih CM (1986) Measurements of wind velocities in a street canyon. Atmos Environ (1967) 20:455–459Google Scholar
  6. Dezso-Weidinger G, Stitou A, van Beeck J, Riethmuller ML (2003) Measurement of the turbulent mass flux with PTV in a street canyon. J Wind Eng Ind Aerodyn 91: 1117–1131. doi: 10.1016/S0167-6105(03)00054-0 CrossRefGoogle Scholar
  7. DIN 1055-4 (2005) Actions on structures—Part 4: Wind loads. Normenausschuss Bauwesen im DIN (ed), Beuth Verlag, Berlin, 101 pp, March 2003Google Scholar
  8. Eliasson I, Offerle B, Grimmond CSB, Lindqvist S (2006) Wind fields and turbulence statistics in an urban street canyon. Atmos Environ 40: 1–16. doi: 10.1016/j.atmosenv.2005.03.031 CrossRefGoogle Scholar
  9. Gayev YA, Savory E (1999) Influence of street obstructions on flow processes within urban canyons. J Wind Eng Ind Aerodyn 82: 89–103. doi: 10.1016/S0167-6105(98)00212-8 CrossRefGoogle Scholar
  10. Gerdes F, Olivari D (1999) Analysis of pollutant dispersion in an urban street canyon. J Wind Eng Ind Aerodyn 82: 105–124. doi: 10.1016/S0167-6105(98)00216-5 CrossRefGoogle Scholar
  11. Gromke C, Ruck B (2005) Die Simulation atmosphärischer Grenzschichten in Windkanälen. In: Egbers C, Jehring L, Larcher T, Ruck B, Leder A, Dopheide D (eds) Lasermethoden in der Strämungsmesstechnik, vol 13. Cottbus, Germany, pp 51.1–51.8, ISBN: 3-9805613-2-1. Brandenburgische Technische Universität, CottbusGoogle Scholar
  12. Gromke C, Ruck B (2007a) Influence of trees on the dispersion of pollutants in an urban street canyon—Experimental investigation of the flow and concentration field. Atmos Environ 41:3287–3302. doi: 10.1016/j.atmosenv.2006.12.043
  13. Gromke C, Denev J, Ruck B (2007b) Dispersion of traffic exhausts in urban street canyons with tree plantings - Experimental and numerical investigations. In: Int workshop on physical modeling of low and dispersion phenomena PHYSMOD 2007 Orléans, France, pp 121–128Google Scholar
  14. Gross G (1987) A numerical study of the air flow within and around a single tree. Boundary-Layer Meteorol 40:311–327. doi: 10.1007/BF00116099
  15. Gross G (1993) Numerical simulation of canopy flows. Springer, Berlin, p 167Google Scholar
  16. Gross G (1997) ASMUS—Ein numerisches Modell zur Berechnung der Strämung und der Schadstoffverteilung im Bereich einzelner Gebäude. Teil II: Schadstoffausbreitung und Anwendung. Meteorol Z 6: 130–136Google Scholar
  17. Hunter LJ, Watson ID, Johnson GT (1991) Modelling air flow regimes in urban canyons. Energy Build 15:315–324. doi: 10.1016/0378-7788(90)90004-3
  18. Kastner-Klein P, Plate EJ (1999) Wind-tunnel study of concentration fields in street canyons. Atmos Environ 33:3973–3979. doi: 10.1016/S1352-2310(99)00139-9
  19. Kastner-Klein P, Fedorovich E, Rotach MW (2001) A wind tunnel study of organised and turbulent air motions in urban street canyons. J Wind Eng Ind Aerodyn 89:849–861. doi: 10.1016/S0167-6105(01)00074-5
  20. Li X, Liu C, Leung DYC, Lam KM (2006) Recent progress in CFD modelling of wind field and pollutant transport in street canyons. Atmos Environ 40:5640–5658. doi: 10.1016/j.atmosenv.2006.04.055
  21. Liu C, Barth MC (2002) Large-Eddy simulation of flow and scalar transport in a modeled street canyon. J Appl Meteorol 41:660–673. doi :10.1175/1520-0450(2002)041<0660:LESOFA>2.0.CO;2Google Scholar
  22. Meroney RN, Pavageau M, Rafailidis S, Schatzmann M (1996) Study of line source characteristics for 2-D physical modelling of pollutant dispersion in street canyons. J Wind Eng Ind Aerodyn 62: 37–56. doi: 10.1016/S0167-6105(96)00057-8 CrossRefGoogle Scholar
  23. Nazridoust K, Ahmadi G (2006) Airflow and pollutant transport in street canyons. J Wind Eng Ind Aerodyn 94:491–522. doi: 10.1016/j.jweia.2006.01.012
  24. Ries K, Eichhorn J (2001) Simulation of effects of vegetation on the dispersion of pollutants in street canyons. Meteorol Z 10:229–233. doi: 10.1127/0941-2948/2001/0010-0229
  25. Ruck B (2005) Über die Aerodynamik der Bäume. In: Egbers C, Jehring L, Larcher T, Ruck B, Leder A, Dopheide D (eds) Lasermethoden in der Strämungsmesstechnik, vol 13. Cottbus Germany, pp 49.1–49.7, ISBN: 3-9805613-2-1. Brandenburgische Technische Universität, CottbusGoogle Scholar
  26. Ruck B, Schmidt F (1986) Das Strämungsfeld der Einzelbaumumsträmung. Forstwiss Centralblatt 105:178–196. doi: 10.1007/BF02741710
  27. So ESP, Chan ATY, Wong AYT (2005) Large-eddy simulations of wind flow and pollutant dispersion in a street canyon. Atmos Environ 39: 3573–3582. doi: 10.1016/j.atmosenv.2005.02.044 CrossRefGoogle Scholar
  28. Vardoulakis S, Fisher BEA, Pericleous K, Gonzalez-Flesca N (2003) Modelling air quality in street canyons: a review. Atmos Environ 37:155–182. doi: 10.1016/S1352-2310(02)00857-9
  29. VDI 3783-12 (2000) Environmental meteorology: physical modelling of flow and dispersion processes in the atmospheric boundary layer—Application of wind tunnels. Verein Deutscher Ingenieure, Kommision Reinhaltung der Luft (KRdL) im VDI und DIN—Normenausschuss (ed), Beuth Verlag, Berlin, 36 pp, VDI 3783 Part 12:2000-2012Google Scholar
  30. Zhou XH, Brandle JR, Mize CW, Mize CW (2002) Estimation of the three-dimensional aerodynamic structure of a green ash shelterbelt. Agric For Meteorol 111: 93–108. doi: 10.1016/S0168-1923(02)00017-5 CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media B.V. 2008

Authors and Affiliations

  1. 1.Laboratory of Building- and Environmental Aerodynamics, Institute for HydromechanicsUniversity of KarlsruheKarlsruheGermany

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