Health risk category for Air Quality Health Index may reach "Serious" Level

     The Environmental Protection Department (EPD) has recorded higher than normal air pollution levels since yesterday afternoon (May 29). According to the EPD's forecast, it is expected that the Air Quality Health Index (AQHI) at some air quality monitoring stations may reach the "Serious" level later today (May 30). The air pollution levels are expected to remain higher in the following few days.

     Under the influence of the outer subsiding air of Typhoon Mawar, the weather today is very hot and mainly fine, light to moderate westerly to northwesterly winds are bringing an airstream with higher regional pollution levels and is unfavourable for pollutant dispersion. The intense sunshine enhances photochemical smog activity leading to rapid formation of ozone and fine particulates in the Pearl River Delta region. The high ozone level also promotes the formation of nitrogen dioxide.

     According to the Hong Kong Observatory, Typhoon Mawar will turn northwards gradually and move slowly in the next couple of days, linger around the seas east of Taiwan. It is expected that air pollution levels will remain higher than normal until a trough of low pressure brings a few showers to Hong Kong.
     With a health risk category in the "Very High" range or above, children, the elderly and persons with existing heart or respiratory illnesses are advised to reduce physical exertion and outdoor activities to a minimum or avoid such activities. The general public is advised to reduce, or reduce to a minimum, outdoor physical exertion, and to reduce time outdoors, especially in areas with heavy traffic. As health effects of air pollutants may vary for individuals, persons who are in doubt or experience discomfort should seek advice from health-care professionals. The public may visit the Centre for Health Protection's website ( for more information on health effects of air pollution and relevant health advice.

     The Education Bureau (EDB) urges all schools to visit the EDB website for appropriate measures to safeguard students' health and take note of changes in the index. The relevant hyperlink is as follows: .
     When AQHI is at the "Very High" level, employers of outdoor workers performing heavy manual work are advised to assess the risk of outdoor work and take appropriate preventive measures to protect the health of their employees, such as reducing outdoor physical exertion and the time of their stay outdoors, especially in areas with heavy traffic. At the "Serious" level, employers of all outdoor workers are advised to assess the risk of outdoor work and take appropriate preventive measures to protect the health of their employees.

     Members of the public can check the current AQHI readings at the EPD's website ( or by calling the hotline 2827 8541.

Ends/Tuesday, May 30, 2023
Issued at HKT 13:45