The International                        UPDATED 30th November 2011
Journal of Ventilation
Published Quarterly www.ijovent.org.uk          Subscribe to Journal  Online 

December 2011 Edition of the IJV now Published  Call for Papers

IJV now included in the Science Citation Index

Paper 4

Effects of Urban Ventilation Patterns on the Carbon Monoxide Concentration in a High-Rise Mega City

Zhiwen Luo¹, Yuguo Li¹ and Wei-Zhen Lu²

¹Department of Mechanical Engineering, The University of Hong Kong, Pokfulam Road, Hong Kong SAR, China

²Department of Building and Construction, City University of Hong Kong, Kowloon Tong, Hong Kong SAR, China

Abstract

Carbon monoxide (CO) concentration data from 1999-2006, monitored at 5 different pollution stations in a high-rise mega city (Hong Kong), were collected and investigated. The spatio-temporal characteristics of urban CO concentration profiles were obtained. A new approach was put forward to examine the relationship between urban CO concentration and different wind flow patterns. Rather than relying on the meteorological data from a single weather station, usually adopted in previous studies, four weather stations on the boundary of Hong Kong territory were used in the present study so as to identify 16 different wind flow patterns, among which a typical urban heat island circulation (UHIC) can be distinguished. Higher concentrations were observed to be associated with the flow pattern of an inflow from Lau Fau Shan (LFS) station which is located in the northwest of Hong Kong. This suggests that the ability of dilution for north-to-west wind is relatively weak due to the pollutants carried from outside Hong Kong. The effectiveness of wind speed on the alleviation of urban concentration is dependent on the initial concentration of the approaching wind. The increase of wind speed of north-to-west wind from 0 m/s to 6 m/s has little effect on the reduction of urban CO concentration, especially on the non-roadside stations. By contrast, for the southerly marine wind, pollution concentration decreases sharply with an increase in the wind speed. It was also found that urban heat island circulation (UHIC) is conducive of the accumulation of pollutants, especially at night. There exists a positive correlation between CO concentration and UHI intensity. This correlation is much stronger at night compared to during the day.

Contents

Paper 1
System Design for Demand Controlled Ventilation in Multi-Family Dwellings

Paper 2
A Long-Term Modelling Study of Ventilation and VOC Distribution in Multi-family Residential Buildings in the Severe Cold Region of China

Paper 3
Evaluating the Influence of Window Types on the Natural Ventilation Performance of Residential Buildings in Hong Kong

Paper 4
Effects of Urban Ventilation Patterns on the Carbon Monoxide Concentration in a High-Rise Mega City

Paper 5
A Measurement Study on the Indoor Climate of a College Classroom

Paper 6
Natural Personalised Ventilation - A Novel Approach

Paper 7
Experimental Study of Turbulent Structures in a Non Isothermal Horizontal Jet Issuing from a Round Nozzle Distanced from a Wall

Paper 8
Case Study Assessment of Local and General Thermal Comfort by Means of Local Skin Temperature

A Guide to Energy Efficient Ventilation

Published in 1996, this Guide is aimed at providing a simplified approach to ventilation with particular emphasis on its impact on air quality and energy demand. Numerical discussion is kept to a minimum but sufficient guidance and data are given to enable basic calculations. 254 Pages. Click here for more details