Study proves air quality is still in need of attention
Updated on Feb 02, 2009 – SCMP
A clear sky and moderate air pollution index reading may seem favourable circumstances for a stroll, but they do not give the full picture. As we report today, a University of Science and Technology study has found that unnoticeable ultrafine particles not adequately measured by the Environmental Protection Department are ever-present, and in some locations, worryingly so. Small amounts are known to cause heart and breathing problems, particularly for the elderly. Higher measurement standards are clearly needed, as is greater effort to reducing the level of roadside pollutants. This is not to say that the government is failing us when it comes to cleaning up the environment. Improved visibility is a fact of life in some parts of the city. The concentration of several major roadside pollutants has fallen 20 per cent over the past decade. Eastern district has not had a reading of more than 100 on the air pollution index since 2005, and with the two other cleanest districts – Tai Po and Sha Tin – has recorded consistently improved figures.
Among the reasons are tighter vehicle emission standards, the introduction of ultra-low-sulfur diesel, the conversion of taxis and minibuses to LPG, and tougher control measures adopted by Guangdong province. All is not sweet air and light, of course – there is a lack of improvement in many other parts of the city. That the situation could be considerably worse than we think at roadsides takes the matter to quite another level.
Decades of air pollution studies have shown that the worse the air quality, the greater the risk of hospital stays and death from heart and lung disease. The fine particles in vehicle emissions have been determined to be more dangerous to health than gaseous pollutants. Microscopic particles – those measured by the university study but not widely taken into account by authorities – were especially troublesome because they could get into the bloodstream and more readily damage lung tissue. Particularly vulnerable were people with heart and lung problems and asthma, and the elderly.
Research at bus stops on Des Voeux Road in Central found invisible particulates were at alarming levels at points where buildings created a “canyon effect”. Levels dropped considerably in open spaces, underground passages and on elevated walkways. The readings are highly localised in nature. Nonetheless, we should be worried that waiting for a bus could be a health risk.
Our air quality standards are considerably lower than those recommended by the World Health Organisation. A government panel is finalising a study that will look into whether these should be adopted. It is clear that they should be – urgently.
More has to be done to cut roadside emissions. Hybrid and electric vehicles have to be encouraged. Urban design has to lessen the canyon effect. Doing so is in all our interests.