eng Science and Education Publishing International Journal of Physics 2333-4576 2015-08-21 3 5 202 207 10.12691/ijp-3-5-1 IJP2015351 article Nada F. Tawfiq laith_najam@yahoo.com 1 Noora O. Rasheed 2 Asmaa Ahmad Aziz 2 Department of Physics, College of Science, AL-Nahrain University, Iraq Department of Physics, College of Education Pure Science, University of Tikrit, Iraq In this study, indoor radon concentration (CRn) were measured by solid state nuclear track detectors in bare mode using CR-39 inside fifteen dwelling at different locations in Baghdad governorate for a period two months. The Potential Alpha Energy concentration (PAEC) in Working Level (WL) of radon daughters, exposure to radon progeny (EP) in (WLM Y-1), the annual effective dose (mSv/y) and the lung cancer cases per year per million person (CPPP) have been studied. The results show that the radon concentration ranged from 83.4 Bq/m3 in Topchi to 238.8 Bq/m3 in Baya with average 116.78 Bq/m3, Potential Alpha Energy concentration values of radon daughters varies from (0.009 to 0.026) WL with an average value of 0.02WL, the annual effective dose rate from 2.10 to 6.02 mSv/y with average 2.95 mSv/y, exposure to radon progeny from 3.71 to 10.62 WLM Y-1 with average 5.2WLMY-1 and the lung cancer per year per million person from 0.88 to 4.46 with average 1.7. The indoor radon concentration was in agreement to radon concentration levels (200 Bq/m3) recommended by the International Commission on Radiological Protection (ICRP). http://pubs.sciepub.com/ijp/3/5/1/ijp-3-5-1.pdf radon concentration CR-39 annual effective dose exposure to radon progeny lung cancer per year per million person