assessment of radon gas using passive dosimeter in amman and al-rusaifa cities, jordan

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 ± 1.2 to 6.9 ± 1.5 (kbq/m3) with an average  4.0 ± 1.6 (kbq/m3)  in amman and  from and  6.5± 1.1 to  22.4 ± 5.2 kbq/m3  in al- rusaifa  with average 14.2 ± 2.5 (kbq/m3). the average indoor radon concentration in the first floor in amman was 44.8± 5.3 (bq/m3); while the average concentration in al- rusaifa, in the first floor, was 187± 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.  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