Very high air pollution in the next few days

Press Release

Very high air pollution in the next few days

The Environmental Protection Department (EPD) recorded very high Air Pollution Indices (API) of 102 and 132 at the Yuen Long and Tung Chung stations respectively at 4pm today (October 5) due to ozone concentrations. It is expected that the general and roadside API readings will remain higher than normal in the next few days.

Under the combined effects of a continental airstream and Typhoon Krosa now located in the Western Pacific Ocean, the weather over South China region is sunny and hot, and the wind is light and prevails from the northwest to west in the Pearl River Delta region. Pollutants are trapped under the light wind, and the sunny and hot weather conditions favour the photochemical formation of ozone in the region in the afternoon, resulting in elevated ozone levels.

With elevated ozone concentrations, the nitrogen oxide emitted from motor vehicles will be oxidised to form nitrogen dioxide quickly. Due to higher nitrogen dioxide levels and poor dispersion under the light wind, the roadside API readings are also expected to increase steadily and reach the very high range later.

According to Hong Kong Observatory, the fine and hot weather will persist and the prevailing wind in the region will remain light. Photochemical activity will still be active and air pollution levels will remain high for the next two to three days.

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.

People can check the latest hourly API readings for different locations on 2827 8541 or from EPD's website at http://www.epd-asg.gov.hk.

Ends/Friday, October 5, 2007