Lina Lim – SCMP
1:00pm, Jan 08, 2008
Pollution levels in Hong Kong on Tuesday reached dangerous levels – according to the territory’s Environmental Protection Department (EPD).
Pollution at general stations in the city recorded unhealthy levels of nitrogen dioxide and respirable suspended particulates between the 61 (high) to 105 (very high) point range.
Meanwhile, roadside stations in Causeway Bay, Central and Mongkok recorded more alarming levels at 91, 111 and 100, respectively.
People with heart or respiratory ailments were advised to avoid going outdoors for prolonged periods of time.
Respirable suspended particles are suspended particulates smaller than 10 micrometres which have the ability to penetrate deeply into the lungs.
Depending on their source and existing meteorological conditions, the particles can be made up of a number of different constituents such as silicon, aluminium, calcium, manganese and iron from construction sites and carbon, lead, bromine and hydrocarbons from vehicular emissions.
Nitrogen dioxide, however, enters the air as a result of combustion processes which involve high temperatures, such as those produced by power plants and vehicular engines.
It is a corrosive light brown gas which can cause urban haze or photo-chemical smog.
Hong Kong has a serous problem with air pollution and the growing government is under pressure to deal with the problem – particularly because of the effect it is having on people’s health.
It has been estimated that over 2,000 people annually die in Hong Kong because of air pollution; while others suffer serious health effects.
A government study several years ago argued that 80 per cent of the city’s pollution came from factories and power plants in southern China.
But a report by the Hong Kong University of Science and Technology and Civic Exchange, a think-tank, argued that in 2006 Hong Kong’s air pollution was largely the result of local factors. This included the city’s road traffic, coal-fired power stations and ships.