Assessment of radon exhalation rate, radon concentration and annual efective dose of some building materials samples used in Yemen

Radon gas has been recognized as one of the health hazards to humans. Building materials used for the construction of houses, which are considered as one of the major sources of this gas in indoor environments. The radon exhalation rate, radon concentration as well as the annual efective dose for 46 samples of building materials (granite, ceramic, marble, mosaic, rocks, gypsum, block and red brick) used in Yemen were measured using two methods. The can technique, containing CR-39 solid-state detector, and active method containing AlphaGuard detector were used. The results obtained from passive and active techniques were found in good agreement. The results showed that the highest values of radon exhalation rate, radon concentration and the annual efective dose indoor and outdoor were 0.93 ± 0.020 Bqm-2 h-1, 186.48 ± 3.73 Bqm-3, 4.7 ± 0.141 and 1.76 ± 0.053 mSvy-1 for granite samples, whereas the lowest values were 0.0076 ± 0.001 Bqm-2 h-1, 1.51 ± 0.03 Bqm-3, 0.04 ± 0.001 and 0.01 ± 0.001 mSvy-1 for the ceramic samples. The results also showed that the radon exhalation rate, as well as the annual efective dose, was found below the world average values of 57.600 Bq m-2 h-1, 1100 μSv y-1 with exception of some samples. The values of radon concentrations for granite samples were in the range of activity levels from 200 to 600 Bq m-3 recommended by (ICRP, 1994).