Comparison of effective dose of Radon 222 in old and new Dwellings in Minab City

Radon 222 is a radioactive, colorless and odorless element with a half -life of 3.83 days. Long term exposure to Radon 222 can cause lung cancer in humans. Building materials such as granite stone is one of the main sources of radon 222. The aim of this study was comparison of effective dose of Radon 222 in old and new Dwellings; Minab City, Iran Indoor and outdoor concentration of radon 222 was measured in 17 new (Al-Mahdi) and 17 old Dwellings (Pari-Taghi) in two seasons, winter 2013 and spring 2013, by a portable Radon meter (model RTM1688-2) and the effective dose was calculated by UNSCEAR equation. Then the effective doses of radon 222 in new and old Dwellings were statistically compared and analyzed.The mean concentrations of radon 222 in indoor air of Pari-Taghi (25 ± 3 Bq/m3) and Al-Mahdi (42 ± 6 Bq/m3) Dwellings were less than the standards of WHO and EPA. The effective doses of radon 222 in Al-mahdi and Pari-Taghi were 1.06 ± 0.15 and 0.64 ± 0.07 mSv/y, respectively. Due to greater use of granite in the new Dwellings, the concentration of Radon 222 and consequently its effective dose in new Dwellings is more in comparison to old Dwellings.