AN average of 300 people a year die in Hong Kong from lung cancer induced by regular inhalation of radioactive radon gas emitted in unnaturally heavy concentrations from the walls of our homes. In Australia, the people most at risk from radon-induced lung cancer are uranium miners. In Hong Kong it is anybody with a roof over his head.
Over time, given stringent building standards and the widespread use of household ion-generators, the death rate could be substantially reduced. Yet the Government's reaction, supported by the Advisory Council on the Environment (ACE) is to tell people to open their windows.
That advice is not entirely out of place. Radon gas builds up where ventilation is poor. Radon gas cannot be entirely avoided even outdoors. Nevertheless, a City Polytechnic study estimated as long ago as 1988 that reducing indoor radon concentrations to Hong Kong's naturally high outdoor level could eliminate one-third of radon-induced lung cancer deaths.
But in modern Hong Kong, more and more buildings are switching away from natural ventilation. And few, if any residents, are aware of the dangers they face. The Government has a responsibility to do more than publish pamphlets warning people to open their windows.
Not everyone is equally threatened. A government survey found five per cent of the residential and 10 per cent of the non-residential buildings covered exceeded the World Health Organisation radiation standard of 200 becquerels per cubic metre. Different building materials with different granite admixtures produce varying levels of radiation. Radiation exposure will vary with the layout of the accommodation and whether the walls are bare, painted or papered.
What the City Polytechnic also recommended, and ACE Chairman Professor Wang Gungwu says the Government will not do, was to follow the example of other countries in setting standards for building materials. That may not be as easy as it sounds, but it should not be dismissed as impossible merely for administrative convenience.
