Exclusive | Air pollution levels in your street revealed with new Hong Kong app PRAISE-HK

New system can call on data down to individual street levels and advise users through real-time colour-mapping on areas to avoid

Alexis Lau says he hopes a new app can help Hongkongers make informed choices. Photo: Xiaomei Chen
On a hot afternoon on July 10 this year, as Super Typhoon Maria swirls 1,185km off the city’s coast, Dr Alexis Lau Kai-hon from the Hong Kong University of Science and Technology examines a melange of colours on an iPad map.

As red, orange and yellow blobs move across the screen of his device, he says: “The pollution tomorrow afternoon will be quite bad. Ozone will be high and most of it will be coming from mainland China this time.”

Print option is available for subscribers only.
SUBSCRIBE NOW
Copyright © 2025 South China Morning Post Publishers Ltd. All rights reserved.