Lin Lin1,2, Jian Hang 1, Xiaoxue Wang3, Xuemei Wang 1, Shaojia Fan1, Qi Fan1, Yonghong Liu2

  • 1 School of Atmospheric Sciences, Sun Yat-sen University, Guangzhou, China
  • 2 Guangdong Provincial Engineering Research Center for Traffic Environmental Monitoring and Control, Sun Yat-sen University, Guangzhou, China
  • 3 Department of Mechanical Engineering, the University of Hong Kong, (null), Hong Kong

Received: May 16, 2016
Revised: August 22, 2016
Accepted: September 29, 2016
Download Citation: ||  

  • Download: PDF

Cite this article:
Lin, L., Hang, J., Wang, X., Wang, X., Fan, S., Fan, Q. and Liu, Y. (2016). Integrated Effects of Street Layouts and Wall Heating on Vehicular Pollutant Dispersion and their Reentry Toward Downstream Canyons. Aerosol Air Qual. Res. 16: 3142-3163.


  • Effects of street layout/wall heating on street pollutant dispersion are studied.

  • Reentry of CO and particles with various sizes into downstream streets are tested.

  • As Fr is small, leeward wall/ground/all wall heating benefit pollutant dispersion.

  • Taller upstream buildings weaken pollutant dilution, large particles tend to deposit.

  • Pollutant reentry rates decrease exponentially toward downstream canyons.



Vehicle emission is becoming one of the major sources of gaseous pollutants and aerosol particles in urban air environments. Apart from pollutant source control, sustainable street design is another significant technique to reduce street air pollution. Under the validation by wind tunnel data, this paper conducts computational fluid dynamic (CFD) simulations by RNG k-ε model to investigate the impacts of typical street layouts and wall heating on the dispersion of gaseous pollutants and particles (diameter d = 1 µm, 5 µm, 20 µm) in the target street canyons and their reentry toward downstream streets.     The dispersion processes of gaseous pollutants and fine particles (d = 1 µm) are found similar. For uniform street layouts (aspect ratio H/W = 1) with small Froude number (Fr = 0.19–0.38), leeward-wall heating, ground heating and all-wall heating significantly enhance the primary clock-wise vortex and improve pollutant dispersion, but windward-wall heating does not. Taller upstream buildings (H1/W = 2–3) produce a clockwise vortex over the target canyon and a much weaker counter-clockwise vortex within it, seriously weakening the capacity of pollutant dispersion. For large particles (d = 20 µm), the major fraction deposits onto street ground because the gravity force dominates particle transportation. For particles of d = 5 µm, the dispersion dynamics are more complicated: In the isothermal case less particles of d = 5 µm suspend in the target canyon than d = 1 µm because the gravity force and particle deposition are more important, however, with all-wall heating more particles of d = 5 µm float in the target canyon because the upward thermal buoyancy force reduces particle deposition onto the ground. Finally for both gaseous pollutants and particles, their bulk concentrations in downstream streets decrease exponentially with increasing distance from the target canyon, whose decreasing rates are quantified. Although further investigations are still required to propose a practical framework, this paper is one of the first attempts to quantify the capacity of street particle dispersion for street design purpose.

Keywords: CFD; Street canyon; Wall heating; Particle dispersion; Pollutant reentry

Share this article with your colleagues 


Subscribe to our Newsletter 

Aerosol and Air Quality Research has published over 2,000 peer-reviewed articles. Enter your email address to receive latest updates and research articles to your inbox every second week.

77st percentile
Powered by
   SCImago Journal & Country Rank

2022 Impact Factor: 4.0
5-Year Impact Factor: 3.4

Aerosol and Air Quality Research partners with Publons

CLOCKSS system has permission to ingest, preserve, and serve this Archival Unit
CLOCKSS system has permission to ingest, preserve, and serve this Archival Unit

Aerosol and Air Quality Research (AAQR) is an independently-run non-profit journal that promotes submissions of high-quality research and strives to be one of the leading aerosol and air quality open-access journals in the world. We use cookies on this website to personalize content to improve your user experience and analyze our traffic. By using this site you agree to its use of cookies.