Air Quality Health Index may reach “Serious” level, posing potential health risks


30th May 2023 – (Hong Kong) The Environmental Protection Department (EPD) has reported higher than normal air pollution levels since the afternoon of 29th May, and it is expected that the Air Quality Health Index (AQHI) at some air quality monitoring stations may reach the “Serious” level later on 30th May. The EPD forecasts that the air pollution levels will remain higher than normal in the next few days.

The hot and mainly fine weather today is due to the outer subsiding air of Typhoon Mawar, which is bringing an airstream with higher regional pollution levels that is unfavorable for pollutant dispersion. The intense sunshine enhances photochemical smog activity, leading to the 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 gradually turn northwards and move slowly in the next few days, lingering around the seas east of Taiwan. Air pollution levels are expected to remain higher than normal until a trough of low pressure brings a few showers to Hong Kong.

The health risk category is in the “Very High” range or above, and 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 minimize outdoor physical exertion and to reduce time spent outdoors,especially in areas with heavy traffic. As the 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 Centre for Health Protection’s website provides more information on health effects of air pollution and relevant health advice.

The Education Bureau (EDB) urges all schools to take appropriate measures to safeguard students’ health and monitor changes in the AQHI. The relevant hyperlink can be found on the EDB website.

When the 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, 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.