Indoor radon measurement in residential/commercial buildings in Isfahan city

Introduction: People are constantly exposed to radiation from natural and artificial sources of radiation. Radon is one of the natural radiation sources that its concentration in very high in some part of the world. The presence of radon gas in the air can increase the risk of lung cancer. In this study, the level of indoor radon in dwellings of Isfahan city was surveyed. It should be mentioned that an active alpha GUARD instrument was used to measure radon concentration. All of the measurments took place during the winter and spring of 2018.   Materials and methods: In the present survey, 51 residential/commercial buildings were considered to radon gas monitoring based on the population distribution on 15 urban areas and the population of each area and technical possibilities. In each residential/commercial buildings, sampling was carried out at different floors of the building. A professional radon monitoring device (Alpha GUARD PQ2000 PRO) was used to measure indoor radon gas con-centration.   Results: The Results of measuring were shown that the radon concentration in the residential/commercial buildings varied from 3 to 251 Bq / m3, with a mean value of 28.57 ± 39.38 Bq / m3. The average annual effective dose re-ceived by the residents of the studied area was estimated to be 0.49 mSv. The results showed a significant difference between the average radon concentra-tion in different floors and the different ventilation of the building, higher values in the lower floors and weaker ventilation.   Conclusion: Indoor radon concentration in 4 % of the building was deter-mined to be higher than the limit (100 Bq / m3) recommended by the World Health Organization.