Angela Seet – Updated on Jan 23, 2009 – SCMP
Air pollution levels in Hong Kong were very high on Friday, with the air pollution index (API) reaching 140 in Central, a spokesman from the Environmental Protection department said.
At 6pm, roadside station readings at Central and Causeway Bay were recorded as “very high” with an API rating of 118 and 103 respectively. The station reading at Mongkok was slightly better at 92, but according to the standards set by the department, it is still considered to be “high”.
The department found that the contributing pollutant to all three station readings was nitrogen dioxide, which causes urban haze, or “photochemical smog”.
Environmental Protection officer Dave Ho said says the air pollutants were not dispersed because of recent calm weather conditions.
“The air is currently affected by the continental airstream, with relatively high background pollution. Over the last two days, the wind was very weak so the pollutants were trapped and thus, pushing up the air pollution index,” he explained.
Mr Ho also said that air pollution levels should reduce in the next few days, if the winds pick up strength as usual.
Between API readings of 101 to 200, air pollution levels are rated “very high” and those with existing heart or respiratory illnesses are advised to avoid prolonged stay in areas with heavy traffic.
“If you have to stay in streets or on roads with heavy traffic, do reduce physical exertion as far as possible,” a spokesman said.
Lawmakers are worried that the approaching 2010 targets for emissions reduction cannot be met as air pollution is not considered a serious threat.
Critics say that the city’s air quality objectives, set more than 20 years ago, are less stringent that the ones set by the World Health Organisation (WHO).
For example, if Hong Kong strictly followed the WHO target for sulfur content, the government would have to reduce current concentration levels by some 95 per cent.