2 ex-HKO directors urge Labour Dept to update heat stress system

Two former Hong Kong Observatory directors Lee Boon-ying and Shun Chi-ming jointly urged the Labour Department to switch the heat stress at work warning system to the wet-bulb global temperature measurement (WBGT).

The pair wrote in Ming Pao that the heat stress index launched in 2014 targeted the general public, including people staying indoors with air conditioning, which gauges how intense the heat would be and how many more people would be hospitalised under the heat.

The Labour Department's 2023 heat stress index now determines critical rest breaks for outdoor labourers. That's why, Lee and Shun say, the heat stress index is mismatched.

The pair also believe that the current threshold for heat warnings is too high. Even when record-breaking temperatures were logged on August 9, the warning was still amber. They suggest switching to the internationally used WBGT for heat warnings.