New | Heat island effect turns tenement flats into 'ovens'
Temperatures on rooftops can hit 70 degrees Celsius on some days
Low-income dwellers living on the top floors of old tenement buildings have become the forgotten victims of the urban heat island effect, a green group has found.
A study on buildings at seven districts including Cheung Sha Wan, Mong Kok and Sham Shui Po, has found surface temperatures on some rooftops can go up to 70 degrees Celsius on some days.
The heat – trapped in bare, unpainted concrete – dissipates into households below turning flats into “ovens”.
“The rooftops of some of these old buildings can get so hot you can fry eggs on them,” said Dr William Yu Yuen-ping, chief executive at the World Green Organisation, the group that carried out the study.
The study, conducted in August, took 38 measurements.
One measurement at Mong Kok one afternoon measured a maximum rooftop temperature of 74.4 degrees. The air temperature in the flat below rose to 36.8 degrees, five degrees higher than the 32 degree mean temperature recorded by the Observatory that day.