radon level in dwellings basement of yazd-iran

background: indoor radon gas (222rn) has been recognized as one of the health hazards for human. air radon comes mainly from basement soil and construction materials. saghand region with rich uranium mines lies 180 km from yazd, so the indoor radon concentration can be high. yazd, with population of about 457000, is the biggest city near saghand, thus, indoor gamma background radiation of yazd could be more than the other cities of yazd province. materials and methods: in this study the air radon level of 84 dwellings basement from various regions of yazd were measured during the year 2007. to do so, a portable radon gas surveyor was used which is an active measurement method. using this device, α radiation of each basement was measured by a solid state detector for 24 hours. results: radon concentrations of the basements were between 5.55 to 747.4 bq/m3 with mean of 137.36 bq/m3. the mean radon concentration wasn't significantly different from the epa guide line that is mitigation recommendations level (148 bq/m3). however, more than 30% of the basements had radon concentration more than epa guide line. conclusion: using good air conditioning system in the dwelling basements is suggested. iran. j. radiat. res., 2008 6 (3): 141-144