Evaluating the role of vegetation on the ventilation performance in isolated deep street canyons
by Wai-Yin Ng; Chi-Kwan Chau
International Journal of Environment and Pollution (IJEP), Vol. 50, No. 1/2/3/4, 2012

Abstract: Vegetation is generally considered as an essential component for a sustainable city as it helps improve its microclimate environment and reduce greenhouse gases emissions. However, there is some evidence suggesting that adverse effects may be caused by tree-planting in shallow urban street canyons. Accordingly, we intended to investigate whether similar observations are found for different canyon geometries, i.e., canyons with aspect ratios higher than 1. Also, we attempted to investigate how the air quality varies with different tree planting densities by using CO as a representative for gas pollutant emitted from vehicle sources. The findings derived from CFD models indicate that tree planting elevates the CO levels inside canyons. Increasing the tree planting density can deteriorate the ventilation performance of canyons and to a greater extent for those with lower aspect ratios. However, the change in ventilation performance is less sensitive to a change in tree planting density at high planting densities. Accordingly, the decision in relation to tree planting in deep canyons should be weighed against other benefits like cooling effect, and energy saving. The findings should be of great value to urban planners in planning a sustainable city.

Online publication date: Wed, 19-Nov-2014

The full text of this article is only available to individual subscribers or to users at subscribing institutions.

 
Existing subscribers:
Go to Inderscience Online Journals to access the Full Text of this article.

Pay per view:
If you are not a subscriber and you just want to read the full contents of this article, buy online access here.

Complimentary Subscribers, Editors or Members of the Editorial Board of the International Journal of Environment and Pollution (IJEP):
Login with your Inderscience username and password:

Username:        Password:          Forgotten your password?

Want to subscribe?
A subscription gives you complete access to all articles in the current issue, as well as to all articles in the previous three years (where applicable). See our Orders page to subscribe.

If you still need assistance, please email subs@inderscience.com