A study on the correlation between the volume of indoor space and the measured concentration of indoor radon

The corelation between the indoor volume and the measured radon concentration has been analyzed by comparing the radon concentration and the indoor volume of apartment rooms in Jeonju City. We also measured the annual exposure dose based on the variation in indoor radon concentration over time. To do this, we took 8 larger rooms and 8 smaller rooms of apartment, respectively, as a sample. The average volume of the larger rooms and that of the smaller rooms were 31.59 m3 and 16.82 m3, respectively. The average radon concentration of the larger rooms and that of the smaller rooms turned out to be 71.73 Bq/m3 and 108.51 Bq/m3. Respectively, indicating that indoor volume is in inverse proportion to the radon concentration, i.e., the bigger the ratio of the surface area/volume, the higher the indoor radon concentration. From the measurement of the variation in indoor radon concentration over time for a single day, the average intraday radon concentration variation was found to be about 46.8 Bq/m3. The highest level of concentration (114.5 Bq/m3) was measured between 8 and 10 AM and the lowest level of concentration (67.7 Bq/m3) between 2 and 4 PM. The annual exposure dose turned out to be in the range of 0.3 mSv/yr to 2.16 mSv/yr, showing that the dose in some apartments exceeded 1.3 mSv/yr, the numerical value presented by the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR)