Next Article in Journal
Social Insurance Accounting for a Notional Defined Contribution Scheme Combining Retirement and Long-Term Care Benefits
Previous Article in Journal
Energy and Seismic Recovering of Ancient Hamlets: the Case of Baia e Latina
Previous Article in Special Issue
Study on Air Pollution and Control Investment from the Perspective of the Environmental Theory Model: A Case Study in China, 2005–2014
Article Menu
Issue 8 (August) cover image

Export Article

Open AccessArticle
Sustainability 2018, 10(8), 2833; https://doi.org/10.3390/su10082833

Are Green Walls Better Options than Green Roofs for Mitigating PM10 Pollution? CFD Simulations in Urban Street Canyons

College of Landscape Architecture & Arts, Northwest A&F University, 712100 Yangling, China
*
Author to whom correspondence should be addressed.
Received: 11 July 2018 / Revised: 6 August 2018 / Accepted: 8 August 2018 / Published: 9 August 2018
Full-Text   |   PDF [6198 KB, uploaded 9 August 2018]   |  

Abstract

To examine the effect of green roofs (GRs) and green walls (GWs) on coarse particle (PM10) dispersion in urban street canyons, a computational fluid dynamics (CFD) simulation was conducted with a Reynolds-averaged Navier-Stokes (RANS) model and a revised generalized drift flux model. Simulations were performed with different aspect ratios (H/W = 0.5, 1.0, and 2.0), greenery coverage areas (S = 300, 600, and 900 m2), and leaf area densities (LADs = 1.0, 3.5, 6.0 m2/m3). Results indicate that: (1) GRs and GWs all had the reduction ability of PM10 at the pedestrian level; (2) Averaged concentrations of PM10 in GWs and GRs varied little as LAD changed in H/W = 0.5 and 1.0. When H/W = 2.0, the aerodynamic effects of GRs increased since airflow was enhanced within street canyons, resulting in the increasing concentrations in GRs compared with non-greening scenarios; (3) Given equal greenery coverage area and aspect ratio, GWs are more effective in reducing street-canyon PM10, and the averaged concentrations declined with increasing LADs and greenery coverage areas, especially the H/W; (4) At the pedestrian level, the reduction ratio of GRs is greater than that of GWs with the maximum value of 17.1% for H/W = 0.5. However, where H/W = 1.0 and 2.0, the concentrations within GWs are lower than GRs, with maximum reduction ratios of 29.3% and 43.8%, respectively. View Full-Text
Keywords: green roofs; green walls; computational fluid dynamics; PM10; greenery coverage; street canyon green roofs; green walls; computational fluid dynamics; PM10; greenery coverage; street canyon
Figures

Figure 1

This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited (CC BY 4.0).
SciFeed

Share & Cite This Article

MDPI and ACS Style

Qin, H.; Hong, B.; Jiang, R. Are Green Walls Better Options than Green Roofs for Mitigating PM10 Pollution? CFD Simulations in Urban Street Canyons. Sustainability 2018, 10, 2833.

Show more citation formats Show less citations formats

Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Related Articles

Article Metrics

Article Access Statistics

1

Comments

[Return to top]
Sustainability EISSN 2071-1050 Published by MDPI AG, Basel, Switzerland RSS E-Mail Table of Contents Alert
Back to Top