en Radiation Biology Radiation Biology گزارش کوتاه Short Report <p></p> <p>Background: Radon concentration was measured in the soil and indoor of Amman and Al- Rusaifa cities in Jordan during summer season. Materials and Methods: The measurement was performed using time-integrated passive radon dosimeters, containing a solid state nuclear track plastic detector, commercially known as CR-39. Results: Radon concentration levels in the soil ranged from 2.8 &plusmn; 1.2 to 6.9 &plusmn; 1.5 (kBq/m³) with an average&nbsp; 4.0 &plusmn; 1.6 (kBq/m³)&nbsp; in Amman and&nbsp; from and&nbsp; 6.5&plusmn; 1.1 to&nbsp; 22.4 &plusmn; 5.2 kBq/m³&nbsp; in Al- Rusaifa&nbsp; with average 14.2 &plusmn; 2.5 (kBq/m³). The average indoor radon concentration in the first floor in Amman was 44.8&plusmn; 5.3 (Bq/m³); while the average concentration in Al- Rusaifa, in the first floor, was 187&plusmn; 16.35 (Bq/m³). In Al- Rusaifa, our results in the ground floor and the first floor were about 11% - 26 % higher than the reported values, while this ratio reaches to 56% of the soil. &nbsp;Conclusion: The average indoor radon concentration indoor in Al-Rusaifa exceeds the action radon level recommend by WHO (100 Bq/m³). The potential health impact in this city is considered high. High radon level in Al- Rusaifa may be due to the phosphate content in its soil. A correlation between the radon concentration in the soil and indoor was observed</p> <p></p> Keywords: Radon, passive dosimeter, Amman, Al- Rusaifa. 367 371 http://ijrr.com/browse.php?a_code=A-10-1-641&slc_lang=en&sid=1 M.K. Alqadi 7900319475328460010020 7900319475328460010020 Yes Department of physics, Jordan University of Science and Technology, Irbid, Jordan F.Y. Alzoubi 7900319475328460010021 7900319475328460010021 No Department of physics, Jordan University of Science and Technology, Irbid, Jordan M.A. Jaber 7900319475328460010022 7900319475328460010022 No Department of physics, Jordan University of Science and Technology, Irbid, Jordan