Radon level and radon effective dose rate determination in Moroccan dwellings using SSNTDs

Inhalation of radon (222Rn) and its daughter product are a major source of natural radiation exposure. The measurement of radon activity in dwelling is assuming ever increasing importance. It is known from recent surveys in many countries that radon and its progeny contribute significantly to total inhalation dose and it is fairly established that radon when inhaled in large quantity causes lung disorder. Keeping this in view, the indoor radon activity level and radon effective dose rate were carried out in the dwellings of Beni-Mellal, Khouribgra and Ben Guerir cities, Morocco, using the solid state nuclear track detectors (SSNTD) technique. Assuming an indoor occupancy factor of 0.8 and 0.4 for the equilibrium factor of radon indoors, we found that the 222Rn effective dose rate in the studied dwellings ranges from 1.01 to 7.90mSvy-1. The radon activity in the corresponding dwellings was found to vary from 40 to 532Bqm-3. The radon activity has not only been found to vary with seasonal changes, but also with the age, the construction mode of houses, the ventilation conditions and with specific sites and geological materials.