Concentrations of ²²²Rn and ²²⁰Rn in Indoor Air

Janja Vaupotič,^a* Igor Čeliković,^b Nataša Smrekar,^a Zora S. Žunić^b and Ivan Kobal^a

^a Jožef Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia.
^b Vinča Institute of Nuclear Sciences, Mike Alasa 12-14, 11000 Beograd, Serbia.
Tel.: +381 11 2458222, Fax: +386 11 3442420, 
E-mail: zzunic@verat.net
* Corresponding author: E-mail: janja.vaupotic@ijs.si
Tel.: +386 1 477 3213, Fax: +386 1 477 3811

Abstract
Radon (²²²Rn) and thoron (²²⁰Rn) were surveyed in indoor air of 15 public buildings and 10 homes in Slovenia in November 2004 by exposing Rn–Tn discriminative etched track detectors. The following ranges of the activity concentration were obtained for public buildings: 98–2680 Bq m^–3 for C_Rn, 19–1330 Bq m^–3 for C_Tn and 0.11–0.72 for the C_Tn/C_Rn ratio. In homes, the C_Rn range was 12–374 Bq m^–3 and all C_Tn values, except one of 29 Bq m^–3, were below the detection limit of 10 Bq m^–3. Monthly effective doses in public buildings due to Rn (E_Rn) and Tn (E_Tn) were in the ranges 0.05–1.45 mSv and 0.01–0.47 mSv, respectively, and in homes, 0.018–0.548 and 0.009–0.095 mSv, respectively. The E_Tn/E_Rn ratio in public buildings was in the range 0.07–0.47.

Keywords: Radon (222Rn), thoron (220Rn), indoor air, effective dose estimate, radon-prone area