A new front in Hong Kong's war on pollution

Hong Kong is, as researchers studying the health effects of roadside air pollution have observed, an "ideal urban laboratory". In many urban districts, canyons of tall buildings line streets, restricting the dispersal of emissions from vehicle exhausts. These are perfect conditions to find out the impact of pollutants on those who have to live with them every day. With such understanding, we can better assess risks and plan with avoidance in mind.

Government and university researchers already have a wealth of information. Improving technology has allowed experts to focus on particular pollutants that have the greatest direct impact on health. But while there are monitoring stations in our busiest districts, there has yet to be a wide-ranging, intensive, collection of data at a range of heights in residential as well as commercial areas. How residents and workers are specifically affected is only generally understood.

The University of Hong Kong's Hedley Environmental Index has for six years been collating data to track the health and financial costs of air pollution to our city; it determines more than 3,000 people die prematurely as a result of it each year, in excess of 150,000 are treated in hospital and the monetary loss is about HK$40 billion. Statistics do not offer solutions, though, nor, given rapid urbanisation in China and elsewhere in Asia, can mistakes be avoided if there is a paucity of research. The 30-month study being jointly carried out on our street canyons by scientists from the University of Hong Kong, King's College London and Canada's University of British Columbia and Simon Fraser University is therefore welcome.

Six sets of monitors will be installed on selected buildings, four outside at different heights and two in flats. Data collected will help assess how pollution from vehicles is trapped in street canyons, the impact at various floor levels and as a result of weather conditions and what happens in homes. Coupled with the medical records of occupants, a better understanding can be drawn of air quality. A tangible result would be buildings and streets designed to minimise the impact of pollution.

Ridding our roads of old, polluting, diesel buses and trucks is essential to making air safer; that requires adopting laws rather than voluntary schemes. But Hong Kong's limited land area makes high-density living along canyon-like streets inevitable. We can minimise pollution but as yet cannot fully eliminate it. Only through research can we find ways to better deal with it.