Excessive Lifetime Cancer Risk Assessment due to Short-Term Indoor/Outdoor Ambient Radon and Gamma Dose Rate Exposures

Ambient concentrations of indoor/outdoor radon and gamma dose rates (GDR) were measured, using RTM 1688–2 and Ludlum micrometer 19, in the Muzaffarabad city. For indoor radon measurements, radon concentrations varied in the range of 16 to 150 Bq m−3, whilst for outdoor environment from 7 to 31 Bq m−3. Average values of indoor and outdoor radon concentrations were found as 46.9 and 13.3 Bq m−3, respectively. For indoor measurements, GDR ranges from 419 to 1486 µGy y−1 with mean value of 846 µGy y−1, whilst outdoor GDR varied from 495 to 1029 µGy y−1 with mean value of 777 µGy y−1. For indoor measurements, annual effective dose ( $${E}_{Rn}$$ ) due to radon exposure ranges from 0.4 to 3.78 mSv y−1 with average value of 1.18 mSv y−1. Radon doses delivered to lungs varied from 0.97 to 9.08 mSv y−1 with an average value of 2.84 mSv y−1. Excess lifetime cancer risk (ELCR) varied from 1.49 × 10−3 to 14.01 × 10−3 with mean value 4.38 × 10−3. Data of current study show that lung cancer cases per year per million person ( $$Lung_{{\text{cancer cases}}}$$ ) ranges between 7.26 and 68.1 per million persons per year with mean value of 21.2 per million persons per year. Present study results reported for $${Lung}_{cancer cases}$$ are lower than ICRP recommended values, viz. 170–230 per million persons. Average value of indoor radon value, viz. 46.9 Bq m−3, for the current study is found to be less than the reference value of 100 Bq m−3 proposed by the World Health Organization (WHO), whilst average value of outdoor gamma absorbed dose rate, viz. 88.7 nGy h−1, for the current study is found to be greater than the world average value of 54 nGy h−1 for outdoor gamma absorbed dose rate in air due to terrestrial sources.