Assessment of Outdoor and Indoor Background Gamma Radiation, the Annual Effective Dose and Excess Lifetime Cancer Risk in Birjand, Iran

The health implication of exposure to gamma radiation in the outdoor and indoor environments has become a major concern worldwide.
This study was conducted in the city of Birjand where three stations and buildings were randomly selected to measure the background radiation in outdoor and indoor places; for this purpose, GM detector (X5C plus) was used. All dose rates on the display of the survey meter were recorded, and the mean of all data in each station and buildings was computed and taken as the measured dose rate of that particular station.
The average dose rate of background radiation was 71.8 nSv/h for outdoor and 82.0 nSv/h for indoor environments, and the maximum and minimum dose rates were 79.6 nSv/h and 61.7 nSv/h for outdoor measurements and 112.9 nSv/h and 70.8 nSv/h for indoor measurements, respectively.
The results revealed that the annual effective dose is 0.49 mSv, which is similar to that of the global level (0.48 mSv). The estimated excess lifetime cancer risk was 1.715 × 10-3, which was high compared to the world average value of 0.25 × 10-3.