Daily and floor variations of indoor radon activity concentration in single-family houses.

In this paper, the results of indoor radon level measurements in thirteen single-family houses, on different floors, are presented. The measurement was performed using the AlphaE radon metre device, and in each house, the measurements lasted six days, on average. The mean values of the radon activity concentration were in the range of 32.32-525.65 and 18.41-185.25 Bq m^-3 for the ground floor and first floor rooms, respectively. The results of the statistical analyses on the variation of the radon level have shown that in nine houses (69 %), there is a significant difference in radon levels, with higher levels on the ground floor compared to the first floor. The variations of the radon levels during the night and daytime hours were also statistically analysed.