Assessment of lung cancer risk due to indoor radon exposure in inhabitants of the state of Azad Kashmir; Pakistan

ABSTRACT

Several epidemiological studies conducted on underground miner's show that exposure to elevated levels of radioactive radon gas is expected to increase the risk of lung cancer. Relative risk of lung cancer is almost linear with radon exposure. Elevated concentrations of radon are not only reported within mines but also for closed indoor environment of general public houses. Measurements of radon play a serious role in scrutinizing public health and safety in homes. Indoor radon measurements were taken over a period of year, using CR-39 detectors. Measured indoor radon concentrations, was converted in to excess relative risk [ERR] factors by using the risk model reported in the Biological Effects of Ionizing Radiation [BEIR VI] report. ERR was calculated for age groups of 35 and 55 years. A careful selection of occupancy factor based on interviews with house occupants has been made. Using this local occupancy factor, average excess lung cancer risk for the age group of 35 and 54 y peoples was found to 0.51 +/- 0.03 and 0.42 +/- 0.03. Similarly average values of ERR for local occupancy factor with ages 35 and 55 years was found as 0.59 +/- 0.03 and 0.45 +/- 0.03. The overall average excess lung cancer risk for the studied area was 0.46 +/- 0.03. The study suggested that United State Environmental Protection Agency [US EPA] occupancy factor gave a higher excess lung cancer risk as compared with the local occupancy factor used for studied areas. The ERR due to indoor radon is within the standard limits and does not pose any serious threat to the occupants of the houses under investigation