Age and sex dependent inhalation doses to members of the public from indoor thoron progeny.

The increased indoor thoron level in Europe, North America and Asia has shown that the exposure to thoron and its decay products cannot be ignored in some environments. The contribution of thoron and its progeny can be a significant component of the total exposure from radon and thoron. In the present paper, radiation dose assessment of members of the public of different age and sex exposed to (220)Rn progeny under different daily life activities is performed through a dosimetric approach. Dose conversion coefficients under typical indoor conditions were estimated to be in the range of 107 nSv (Bq h m(-3))(-1) for infant to 81.7 nSv (Bq h m(-3))(-1) for adult. The results of this work emphasized that small children receive a radiation dose of 25% more than adults under the same conditions, and people performing exercise receive a radiation dose 100% more than when sleeping. The results of this work are appropriate to the risk assessment of thoron exposure to members of the public who live in areas with high radon and thoron concentrations.