Estimation of health risk and effective dose based on measured radon levels in Korean homes and a qualitative assessment for residents' radon awareness

More than 50% of the worldwide effective radiation dose from natural sources is known to be due to Rn-222. Indoor radon levels were measured in homes with long-term exposure and in relation to time spent for residents. Measurements were conducted after categorizing homes by type, and the results (mean +/- S.D) showed that detached houses, apartments and multifamily houses had radon concentrations of 97 +/- 110, 51 +/- 24 and 59 +/- 34 Bq/m(3), respectively. Surveys were conducted with 620 people to analyse resident awareness of radon levels and time that residents spend in homes. Using these results, the annual effective dose and risk level were computed. The survey showed that residents of Korean homes had little awareness regarding the source of radon, exposure routes and contamination levels. The excess risk of lung cancer after exposure for 70 years was determined to be 0.55/100 people, which jumped to 2.7/100 people for residents in detached houses in highly exposed areas. Compared to the effects of radon exposure in workplaces and schools, the health risks from radon in Korean homes are especially high. Therefore, the management policies for susceptible groups are important.