'HK to see more red and black heat stress warnings'

The Labour Department in Hong Kong has announced a more sensitive heat stress warning system for the workplace, effective from Friday. This upgrade aims to better respond to extreme heat conditions, potentially leading to more red and black heat stress warnings in the future. The system will now trigger an amber warning immediately upon the Hong Kong Observatory issuing an extreme heat alert.

Additionally, the threshold for raising the warning level will be lowered, allowing for earlier activation. Moreover, if temperatures reach 35 degrees Celsius or higher at 40 percent of the city's 39 monitoring stations, the warning level will automatically increase by one step.

Deputy Commissioner (Occupational Safety and Health) Ivanhoe Chang explained the changes during an RTHK radio program. He stated that the city can anticipate more days with higher warning levels under the improved system. Chang anticipates "four to seven days of red warnings, while there would be one to two days of a black warning" if future weather conditions align with the trends observed over the past three years.

The enhanced system will continue to rely on the Hong Kong Heat Index, which considers temperature, humidity, wind speed, and solar radiation. While Chang did not choose the Wet Bulb Global Temperature measurement system, he noted that both methods have their strengths. He explained that due to Hong Kong's relatively humid summer climate, the Heat Index, which places a higher emphasis on humidity, can better reflect the city's subtropical conditions.

However, the department remains open to exploring other evaluation tools in the future. Chang also emphasized that the department will continue to monitor the performance of the refined system to determine if further adjustments are necessary.