Smog from northern China swept into Hong Kong on Sunday, leading to worsening air quality across the board.
Eight of Hong Kong’s 18 districts were under “very high” health risk between 6 p.m. and 8 p.m., or an Air Quality Health Index reading of 8 to 10, Sing Tao Daily reports.
Air quality in Causeway Bay and Tung Chung were “moderate risk” on Sunday morning, according to the Environmental Protection Department.
By Sunday afternoon, Tung Chung had the worst air quality among all districts, with the index rising to 10.
Its PM2.5 reading of airborne particulates under 2.5 microns that can penetrate deep into the lungs was four times higher than the standard.
The index in Tsuen Wan, Yuen Long and Tuen Mun also climbed to as high as nine. Causeway Bay and Central topped off at eight.
Smog had a greater impact on western Hong Kong.
At 2 p.m. Sunday, visibility in Chek Lap Kok was 3.5 kilometers compared with 12 km. in the Eastern district, according to the Hong Kong Observatory.
The EPD said Hong Kong was being affected by airflow with higher density of pollutants that could linger longer due to weak winds.
Also, the sunshine enhanced photochemical activity and the formation of ozone during the day, resulting in higher pollution, Ming Pao Daily reported.
Air pollution is expected to persist at higher levels for a few days.
Lee Sai-ming, senior scientific officer of the Observatory, said winds are projected to be stronger on Monday, helping improve air quality.
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