This Sept 27, 2016 photo shows buildings shrouded by smog in Hong Kong. (PARKER ZHENG / CHINA DAILY

HONG KONG – Hong Kong’s Environmental Protection Department said Wednesday the city’s Air Quality Health Index (AQHI) was in the “serious” health risk category, and warned that air pollution levels are expected to remain higher in the next two days.

The department recorded higher than normal pollution levels since Wednesday morning as the city is under the influence of a high background pollution airstream.

According to the Hong Kong Observatory, a broad area of low pressure will bring unsettled weather early next week. The air quality levels are expected to improve

The AQHI reached 10+ at 2 pm, the department said in a statement.

The Air Quality Health Index (AQHI) is a pollution evaluation system used by the EPD to provide hourly updates. AQHIs are reported on a scale of 1 to 10 and 10+ and are grouped into five health risk categories of "Low", "Moderate", "High", "Very High" and "Serious”.

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When the AQHI reaches "very high" or "serious" levels, the public is advised to reduce the time spent outdoors, especially in areas with heavy traffic. 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.

According to the Hong Kong Observatory, a broad area of low pressure will bring unsettled weather early next week. The air quality levels are expected to improve.

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