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A numerical study of reactive pollutant dispersion in street canyons with green roofs

Moradpour, M ; Sharif University of Technology | 2018

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  1. Type of Document: Article
  2. DOI: 10.1007/s12273-017-0373-0
  3. Publisher: Tsinghua University Press , 2018
  4. Abstract:
  5. Roof greening is a new technique for improvement of outdoor thermal environment which influences air quality through its impacts on thermal and flow field. In order to examine effects of green roofs on reactive pollutant dispersion within urban street canyons, a computational fluid dynamics (CFD) model was employed which contained NO-NO2-O3 photochemistry and energy balance models. Simulations were performed for street canyons with different aspect ratios (H/W) of 0.5, 1.0, and 2.0 such that leaf area density (LAD) of green roofs changed. It was found that roof greening led distribution of pollutants to alter for H/W = 0.5 and 1.0 cases in such a manner that their averaged concentrations had small variations as LAD changed. However, by increasing LAD in H/W = 2.0, ventilation efficiency of nitrogen oxides increased since the flow was enhanced within the canyon. Additionally, averaged concentration of ozone in H/W = 2.0 increased with increasing LAD, owing to downward flux of ozone at roof level. Results show that roof greening is a good strategy which can be used in order to improve air quality and thermal environment, especially within deep street canyons. © 2017, Tsinghua University Press and Springer-Verlag Berlin Heidelberg
  6. Keywords:
  7. CFD ; Dispersion ; Green roof ; Photochemistry ; Air pollution ; Air quality ; Aspect ratio ; Chemical reactions ; Computational fluid dynamics ; Computer integrated manufacturing ; Dispersion (waves) ; Nitrogen oxides ; Ozone ; Photochemical reactions ; Pollution ; Computational fluid dynamics modeling ; Energy balance models ; Outdoor thermal environment ; Pollutant dispersions ; Reactive pollutant ; Urban street canyon ; Ventilation efficiency ; Roofs
  8. Source: Building Simulation ; Volume 11, Issue 1 , February , 2018 , Pages 125-138 ; 19963599 (ISSN)
  9. URL: https://link.springer.com/article/10.1007/s12273-017-0373-0