A Survey of Radon Properties for Dwellings for Hong Kong

A number of properties related to radon have been surveyed for dwellings in Hong Kong. These properties include the radon concentration, the total potential alpha energy concentration of radon daughters, the equilibrium factor and the fraction of unattached radon daughters. These properties seem to have no obvious relationship with the geographical or geological factor, but are significantly different for sites with air conditioning and those sites with electric fans or natural ventilation only. From the data collected in the present investigation, the mean annual equivalent dose values due to the inhalation of indoor air in dwellings have been calculated. Considering the difference between the radon properties of dwellings and offices in Hong Kong, an estimation of the average indoor radon dose has been made. Finally, considering other sources of natural radiation, a rough estimate was obtained of the total annual equivalent dose of about 2.7 mSv for a person living in Hong Kong, which is lower than a previous estimate but higher than the typical values commonly used.