The Effects of Internal Wall Covering Materials on Hazards of Indoor Radon Concentrations in Houses of Iran

Background: Radon gas emanating from underground can concentrate indoor and reach levels, which represent a risk to people's health. According to WHO (World Health Organization) and EPA (Environmental Protection Agency), radon is the second leading cause of lung cancer in the world. Due to the direct correlation of lung cancer and radon exposure, it is ideal to evaluate the hazards of radon accumulation in the Iran dwellings with different materials by direct measurement of the radon concentrations using accurate, simple and fast method. The aim of this study was to measure variation of radon concentrations with different covering materials on internal building surfaces including walls, which are used in Iran dwellings. Methods: A special chamber with changeable walls of different covering materials (gypsum, wallpaper, oil dye, plastic dye, wood board, and Belka) was made. Radioactive lantern mantles were used for elevating the radon (Rn-220) levels in the chamber artificially. Ventilation in the chamber had been such way that accumulation of radon could be possible. Active measurement by Prassi portable radon gas surveyor was performed for staging purposes. Results: The average radon concentration for wood and plastic dye was 869.0 +/- 66.7 and 936.8 +/- 60.6 (bq/m(3)), respectively, while that for wallpaper and gypsum was 449.2 +/- 101.7, 590.9 +/- 49.0 (bg/m(3)), significantly lower than other covers. The average radon concentration for oil dye and Belka cover was 668.3 +/- 42.3, 697.2 +/- 136.7 (bq/m(3)), respectively. Conclusion: Individuals living in a house with internal wall covering materials of gypsum and wallpaper receive an average annual dose smaller than one living in a house with internal wall covering materials of wood board and plastic dye. Using wallpaper and gypsum as an internal cover for the dwellings suggested.