A woman takes a photo with her phone while rain falls over Victoria Harbour in Hong Kong on July 20, 2021. (ISAAC LAWRENCE / AFP)

HONG KONG - The health risks from air pollution in Hong Kong may reach “serious” levels later on Saturday, according to the Hong Kong government's Environmental Protection Department.

In a statement, the EPD said it had recorded higher than normal air pollution levels since Friday and it is expected that the Air Quality Health Index at some general and roadside air quality monitoring stations may reach the "serious" level later on Saturday.  

Under the continuing influence of the outer subsiding air of Tropical Cyclone In-fa, the weather in Hong Kong is very hot with light winds today, which is unfavorable for pollutant dispersion.

Environmental Protection Department, HKSAR govt

It warned that the air pollution levels are expected to remain higher in the next two days.

READ MORE: HK govt warns of bad air quality due to approaching typhoon

“Under the continuing influence of the outer subsiding air of Tropical Cyclone In-fa, the weather in Hong Kong is very hot with light winds today, which is unfavorable for pollutant dispersion,” the EPD said.

“The intense sunshine enhances photochemical smog activity and the rapid formation of ozone and fine particulates in the Pearl River Delta region. The airstream with high regional background pollutant concentrations is affecting Hong Kong. The high level of ozone has promoted the formation of nitrogen dioxide,” it added.

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According to the Hong Kong Observatory, a southwesterly airstream is expected to bring showers to the coast of southern China next week. It is expected that pollution levels will remain higher until then.

The Air Quality Health Index is reported on a scale of 1 to 10 and 10+, and is grouped into five health risk categories – low, moderate, high, very high, and serious.

ALSO READ: Air pollution declines, but test remains

With a health risk category in the "very high" or "serious" levels, children, the elderly and people with existing heart or respiratory illnesses are advised to reduce physical exertion and outdoor activities to a minimum or avoid such activities, according to the statement.

The general public are advised to reduce, or reduce to a minimum, outdoor physical exertion, and to reduce time staying outdoors, especially in areas with heavy traffic.