家屋内外ラドン娘核種の挙動

1軒の家屋内外での核種別ラドン娘核種濃度の同時連続測定

抄録

Continual and simultaneous measurements of individual concentrations of short-lived radon daughters (RaA, B, and C) were performed in a house under normal living conditions and in the open air. Based on data collected over a period of two years, the relationship between indoor and outdoor radon daughters was discussed.
The averaged diurnal variation and the seasonal variation of radon daughters in indoor air showed the same pattern as those in outdoor air. From a comparison of the variation patterns with the inhabitants' living habits, it was estimated that in this house the contribution of human activities to concentrations of indoor radon daughters was smaller than that of natural activities, such as those featuring meteorological factors.
The concentrations of indoor and outdoor radon daughters depended strongly on wind velocity and outdoor temperature, and no difference was found between indoor and outdoor air in the influencing factors. Based on the linear combination of the two meteorological factors, prediction of the level of the daily mean of the nuclides was attemped. Despite the simple methodology, the predicted values were found to agree with the experimental ones with considerable accuracy.