Dan Mei1,2, Qihong Deng 1, Meng Wen2, Zhi Fang2

  • 1 School of Energy Science and Engineering, Central South University, Changsha (410083), Hunan, China
  • 2 College of Resources and Environmental Engineering, Wuhan University of Science and Technology, Wuhan (430081), Hubei, China

Received: July 6, 2015
Revised: August 31, 2015
Accepted: November 6, 2015
Download Citation: ||https://doi.org/10.4209/aaqr.2015.07.0436  

  • Download: PDF


Cite this article:
Mei, D., Deng, Q., Wen, M. and Fang, Z. (2016). Evaluating Dust Particle Transport Performance within Urban Street Canyons with Different Building Heights. Aerosol Air Qual. Res. 16: 1483-1496. https://doi.org/10.4209/aaqr.2015.07.0436


HIGHLIGHTS

  • The Lagrange approach was used to simulate particle concentration levels.
  • The transport performance of particles from high-level sources are evaluated.
  • High-rise buildings hinder dust transport because of its low transport efficiency.
  • Step-down building arrangement is appropriate for developing cities.
  • The fluctuating velocity is the dominant cause of particle suspension in canyons.

 

ABSTRACT


In developing cities, buildings with different heights obstruct the diffusion of pollutants. In this study, dust particles transported within urban street canyons were simulated using Reynolds-averaged Navier–Stokes (RANS) method, and air-solid two-phase flow fields were obtained on a regional scale. Four typical street building models were used in this study: (a) low-rise buildings (H/b = 1), (b) step-up building arrangements (H/b = 1, 2, 3, 4, 5), (c) step-down building arrangement (H/b = 5, 4, 3, 2, 1), and (d) high-rise buildings (H/b = 5). The particle volume fraction distribution in the four models reflected the basic properties of particle transportation in the canyons. Vortices were observed on the roofs of street canyons, which prevented particles from being transmitted into the canyons, and the vortex regions were characterized as low particle concentration.

To evaluate the dust particle transport performance in the models, three indices, namely particle transport efficiency, suspension fraction and suspension density, were defined. These concepts were based on the particle number concentrations, which were obtained using the Lagrange approach. The high-rise building model (H/b = 5) demonstrated the lowest transport efficiency among all four models, and it also had the lowest suspension density in the street canyons. This implied that the high-rise buildings hindered the particles from being transporting further and that the particles could not enter the deep canyons easily. In the step-down building arrangement model (H/b = 5, 4, 3, 2, 1), the particle concentration level and suspension density in the canyons were lower than those observed in the step-up building arrangement model (H/b = 1, 2, 3, 4, 5), indicating that a step-down building height arrangement is appropriate for creating construction plans for developing cities.

Finally, the variation of the streamwise air velocity, vertical velocity and fluctuating velocity on the roof of canyons along the x direction were separately examined. Notably, the fluctuating velocity was the dominant mechanism of the particle suspension in the canyons.


Keywords: Building arrangement; Particle number concentration; Transport efficiency; Suspension fraction; Fluctuating velocity


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.

6.5
2021CiteScore
 
 
77st percentile
Powered by
Scopus
 
   SCImago Journal & Country Rank

2021 Impact Factor: 4.53
5-Year Impact Factor: 3.668

Aerosol and Air Quality Research partners with Publons

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.