Indoor radon levels in irbid and health risk from internal doses

Abstract Radon gas is known to contribute a high internal dose to some people in some parts of the worlds. But globally, the average dose contributed from radon is estimated more than 40% of the total dose that some persons received. The risk concern has been resulted because of mortality increase due to lung cancer in Irbid (Jordan). Due to this, Irbid was divided into seven districts, namely: eastern, southern, northern, Zabdah, al-Barha, City center and al-Hussein area. About 678 radon monitors were distributed among semi-randomly selected houses (taking in considerations the age, number of floors, types of building materials and the inhabitants’ behaviors). The retrieved detectors were chemically etched and the track density ( tracks cm - 2 ) was optically counted. The results obtained show that radon concentrations vary widely between districts ( 7 – 230 Bq m - 3 ) and among different floors in the same district ( 6 – 168 Bq m - 3 ) . In spite of this, the mean values of radon in different regions were not widely scattered. The lowest value ( 19 Bq m - 3 ) was found in al-Hussein area and the highest one ( 83 Bq m - 3 ) was found in the southern district. However, the overall radon concentration in Irbid was about 44 Bq m - 3 , which is around the national figure. Moreover, the lung cancer risk factor to the inhabitants of this city, according to some available models, was calculated about 0.32%.