An energy efficient approach for radon management. Part I: Radon assessment.

This paper involves assessing radon concentrations at the heating, ventilating and air conditioning (HV AC) environment of Hong Kong University of Science of Technology (HKUST). Ninety rooms with various configurations were selected at random and evaluated in detail. A time-integrated active sampling instrument as well as a passive activated charcoal canister radon detection system were used for the study. With the central HV AC system in the normal operating mode, data on location characteristics, as well as average and peak radon concentrations were collected and analysed. The results indicated that radon concentrations increased linearly as a function of the length of the HV AC shut off period. On the other hand, after the HV AC system was resumed, radon concentrations dropped exponentially. While the average radon level (106.78 Bq/m3 ) for all samples was approximately 50% of the World Health Organisation's (WHO) recommended level (200 Bq/m3), about 10% of the actual readings in excess of this WHO limit. 46% of the these rooms also showed peak average radon concentration (264.39 Bq/m3) exceeded this WHO limit. Factors which influence the result were identified and evaluated.