On the waterfront facing Port Shelter and Sai Kung the University of Science and Technology operates an air monitoring station called a “supersite”. It records the air pollution we all breathe in month by month.
Professor Chan Chak-keung of the Division of the Environment advises residents to reduce outdoor activity when air pollution is severe. Don’t jog on the main roads or spend too much time in Sai Kung town. He showed SAI KUNG BUZZ Professor Jian Yu’s graph of monthly readings from three years ago, the latest available.
The air monitoring station is called a “supersite”, because it is far more sophisticated than most such installations. It measures the concentration and constituents of particulate matter (PM) of less than 2.5 microns in diameter.
The dangerous particulates are from vehicle exhaust, biomass burning (vegetation, agricultural waste and kitchen and restaurant exhaust) and residual oil combustion (dirty oil burning from ships, ferries and boats). This particulate matter contains heavy metals and other carcinogens.
Secondary nitrate and sulphate formation processes are likely traced to vehicles, industries and power stations in the Pearl River Delta. Their health impact is less obvious. The crustal matter recorded is soil, dust and construction materials.
Chak said that because of the UST location by the sea some distance from urban Hong Kong the air pollution recorded there is mainly from regional sources. There is little local emission. In the summer the prevailing winds will be from the southern oceans and the air much better. Rain, too, may have cleared it. The rest of the year the air is worse.
Should residents consider leaving because of air pollution? “No,” Chak said, “Sai Kung and Clearwater Bay are not that bad.” With his wife and son he used to live in Kowloon Tong near Lung Cheung Rd. In April one year his son was admitted to hospital twice with respiratory problems and his wife once. That was when Chak decided to move his family to the UST campus.
He exercises on a treadmill in an air-purified gym. It is not wise to run or hike on main roads, he said. In town the bad particulates can build up from the vehicle, kitchen and restaurant exhausts along with pollution wafted in by northerly winds. The best exercise may be swimming because water droplets near your face will partially remove particulates.
Does he favour masks? He said they may be 30 per cent effective. But they wouldn’t really work unless sealed to your face. All you can do on bad air days is stay indoors with air purifiers on.