HONG KONG: World famous for its skyscrapers, Hong Kong's bustling urban
landscape now faces a shortage of good air ventilation.
Medical experts and environmentalists have expressed concern over the
proliferation of the concrete jungle creating a "wall effect", blocking the flow
of fresh air.
Many residential high-rises are built along the waterfront where the sea
views are a prime real estate commodity. However, for many residents living in
apartment buildings further back, the availability of fresh sea air has become
less of a right, and more of a privilege.
According to a study conducted by community group Green Sense, 104 out of 138
private residential estates developed over the past 10 years had met three or
more criteria of the wall effect.
The criteria included less than 15 meters' space between buildings, building
height over 35 storeys, building facing prevailing wind and the existence of
shorter buildings behind taller ones.
The green group was concerned that the problem would worsen as the plot
ratio, which defines the total floor area of buildings permitted to be
constructed on a site, for 36 old district redevelopment projects had been
increased by five to 12 times. The higher the plot ratio, the taller the
For example, the redevelopment project in Tsuen Wan would result in two
45-storey buildings, while most of the existing buildings in the old districts
are only four to six-storeys.
Hong Kong Medical Association council member Alvin Chan said the ventilation
of areas behind tall buildings would be affected. He expressed concern that the
temperature of these areas would go up, making it stuffy and uncomfortable for
The Hong Kong Observatory had found that the wind speed in some urban areas
had dropped by 0.57 meter a decade from 1968 to 2005. The average wind speed of
remote Waglan Island in October was 17.6 kilometers per hour, while that in the
urban areas like King's Park was only 7.1 kilometers per hour.
"The spread of flu, respiratory and heart disease will also be more serious
in cramped areas with little wind," he said.
"The pollutants will not be easily dispersed in these areas."
The Housing, Planning and Lands Bureau and the Environment, Transport and
Works Bureau recently jointly issued a notice that listed ventilation as a main
concern for redevelopment and large infrastructure projects.
The government would also encourage the private sector to voluntarily assess
ventilation before starting building projects, and also restrict building
heights in certain areas.
Green Sense chairman Roy Tam Hoi-pong said the government should make the
notice a law, making ventilation a compulsory concern for infrastructure
"Only making it a voluntary consideration is not enough," Tam said.
Apart from limiting building height and plot ratio, Tam suggested making it a
compulsory requirement that the distance between buildings be at least 15
Bernard Lim, a Town Planning Board member, said developers should create
models before starting building projects. The model will be used to test the
ventilation, and find out whether the space between buildings and the scale of
the projects should be maintained.
(China Daily 04/03/2007 page5)