Kindergartens have been advised to suspend vigorous outdoor activities for children today because of the "moderate to very high" health risk of anticipated poor air quality, as measured under a new system.
Launched today, the new Air Quality Health Index (AQHI) replaces the Air Pollution Index (API), which had been in use since 1995.
According to the Environmental Protection Department's AQHI forecast, the health risk today will be "moderate" at the 12 general stations across the city. At the three roadside stations in Causeway Bay, Central and Mong Kok, the risk stands at "moderate to very high".
The new system measures the short-term health risks of air pollution by analysing the three-hour average concentrations of four major pollutants - ozone, nitrogen dioxide, sulphur dioxide, and particulate matter (PM10 and PM2.5).
The index is reported on a scale of one to 10 and 10+, and is grouped into five health-risk categories - low, moderate, high, very high and serious.
According to the Education Department's guidelines under the "moderate to very high" health risk, schools should avoid making students stay outdoors for too long, especially in areas with heavy traffic.
Kindergartens should avoid "vigorous activities" for children, such as chasing games, playing on slides, running and jumping. "Prolonged outdoor activities" are also undesirable.
The Labour Department has also issued guidelines to employers of workers doing heavy manual work outdoors.
When the AQHI reaches "very high" and "serious" levels, bosses should postpone low-priority outdoor work and avoid such work in areas with heavy traffic. They should also provide their workers with mechanical aids to reduce physical exertion and arrange more breaks for them.
But Construction Industry Employees' General Union chairman Chow Luen-kiu said: "The guideline is non-binding. Employers do not necessarily have to observe it … The new index offers no extra protection. It tells us only how bad the air quality is, but there is no solution."
The Environmental Protection Department has also launched a mobile application today to track the city's air quality. Users can check the air quality index, get real-time alerts of poor air quality in the vicinity, and obtain advice on whether to take shelter indoors. The app is available for download for Apple and Android smartphone users.