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The Air Pollution Index reached the "very high" band at all the three roadside stations starting yesterday, with nitrogen dioxide being the culprit pollutant, a spokesman for the Environmental Protection Department said today (October 23).
At 3pm today, the API at Central, Causeway Bay and Mong Kok roadside stations were respectively 160, 121 and 120. In addition, the general station at Tung Chung also recorded "very high" API at 105 due to ozone at the same time.
The spokesman said under the combined effects of a continental airstream and the subsidence air of tropical storm "Lupit", the weather was fine and dry with light wind in theĦ@region today. The strong sunshine enhanced the photochemical smog activity and formation of an ozone region. The pollutants could not disperse effectively under the light wind and higher levels of ozone had been recorded in the general stations.
"The very high roadside API readings are caused by the trapping of pollutants emitted from vehicles under the poor dispersion in the urban area under the light wind, coupled with elevated regional background pollution levels.
"According to the Hong Kong Observatory, the weather will be dry and hazy with light wind in the coming few days. We expect that the background pollution will still be higher than usual while the dispersion in urban areas will be poor. The roadside and general API will remain higher than normal in the next few days," added the spokesman.
The spokesman advised that with an API in the very high range, people with heart or respiratory illnesses should reduce physical exertion and outdoor activities, and avoid prolonged stay in roads and streets with heavy traffic.
Members of the public can check the current API readings from the EPD's website at (www.epd-asg.gov.hk/eindex.php) or by calling the hotline at 2827 8541.
Ends/Friday, October 23, 2009
Issued at HKT 19:03
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