Hong Kong government housing plans may intensify 'heat island' effect, warns academic

Ambitions to add hundreds of thousands of flats to the concrete jungle of Hong Kong could intensify the "heat island" effect - and possibly cause deaths - because a loophole in government rules does not encourage better designs that facilitate sea breezes, an academic has warned.

In Kwai Chung, daily mean temperatures may rise 1 degree Celsius after two open spaces are sacrificed to accommodate 800 new public rental flats, according to Professor Edward Ng Yan-yung, an air ventilation specialist at Chinese University.

This was because the project would remove more than 0.6 hectares of trees from the open spaces within Kwai Shing Circuit, while the resulting high-rises would block sea breezes blowing in from the south in summer.

"Local public health studies have found that, at above 28 degrees, an average 1 degree increase in daily mean temperature will drive up the death rate caused by heat-related sicknesses by 1 to 2 per cent," Ng said.

The professor was commissioned by the Planning Department in the early 2000s to study the city's wind environment, including the detailed distribution and directions of sea breezes, a major way of cooling the city in summer.

The study was completed in 2012 and the department published the report on its website, but never incorporated the research findings into its air ventilation guidelines, Ng said.