The Environmental Protection Department has recorded higher than normal pollution levels, with ten out of 16 air monitoring stations showing a “very high” health risk.
The Air Quality Health Index states that levels 8 to 10 represent a very high level of health risk. At 3pm its air monitoring stations in Central, Causeway Bay, Mong Kok, Tsuen Wan, Tai Po and Tap Mun stood at 8; Tung Chung was at 9 and Tuen Mun was at 10.
“It is expected that the AQHI at some general and roadside air monitoring stations may reach the ‘Serious’ level later today,” it said, warning of a higher health risk.
With a health risk category in the “very high” range or above, children, the elderly and people with existing heart or respiratory illnesses have been advised to reduce physical exertion and outdoor activities to a minimum or avoid such activities.
The general public are advised to reduce time staying outdoors, especially in areas with heavy traffic.
The Environmental Protection Department said there were sunny periods with light winds in Hong Kong on Friday, and higher than normal levels of nitrogen dioxide have been recorded in the territory since Friday morning.
It said Hong Kong was being affected by an air mass with higher background pollutant concentrations. The light wind also hindered effective dispersion of air pollutants.
It added that sunshine enhances photochemical smog activity and the formation of ozone and fine particulates, resulting in high pollution in the Pearl River Delta region. The high level of ozone promoted the formation of nitrogen dioxide, particularly in parts of the urban areas and at the roadside.
According to the Hong Kong Observatory, there will still be light winds for a couple of days.
The Environmental Protection Department said it expected that pollution levels will remain higher than normal until the wind strengthens early next week.