Radon activity in Saudi houses

Long term measurements of radon's concentrations inside Saudi Houses being studied using CR-39 Plastic Track Detectors fixed inside sealed plastic cups. The cups were left for about 7 months in the houses. The measurements were done in different cities of different provinces in the country. The analysis of 636 cups showed that the radon concentration in different cities was ranging from 0.27 pCi/1 (in Khobar) to 0.98 pCi/1 (in Taif). In exceptional places in Eastern Province, it is found that the lowest concentration was in the University offices (0.13 pCi/1) and the highest was in the University unoccupied houses (0.81 pCi/1). It is found that the ventilation is the main factor affecting the radon concetration in houses.