INVESTIGATING THE CONFIDENCE LEVEL OF SAMPLING SCHEMES FOR ASSESSING INDOOR RADON CONCENTRATION

摘要

The continuous sampling is one of the common approaches for assessing indoor radon level. Measurements at various sampling periods, such as 0.5, 1, 2, 4 or 8 hours, are proposed for the assessment purpose. It is generally believed that the longer the measurement time, the higher the confidence level can be obtained. This study proposes an alternative sampling scheme, in which the average radon concentration is obtained from two short sampling periods, that offers a reduction in measurement time without any penalty of the confidence level. An indoor radon concentration database mapped from a typical year-round-monitored open-plan office building in Hong Kong is used to assess different measurement schemes. The probable errors of the sampling schemes deviated from a long-term average value are correlated with the required measurement time. The result shows that at certain confidence levels, the potential reduction in the measurement time of the alternative sampling scheme would be up to 50% as compared with that of an 8-hour continuous one.