Influence of radioactive aerosol and biological parameters of inhaled radon progeny on human lung dose

The present work focuses on assessing the influence of biological and aerosol parameters on human lung dose. The dose conversion factor (DCF), which gives the relationship between the effective dose and the potential alpha energy concentration of inhaled short-lived radon progeny (Po-218, Pb-214, Bi-214/Po-214) is estimated using a dosimetric approach related to the International Commission on Radiological Protection((1)) (ICRP). The calculations are based on the measurements of the distribution of activity size of indoor radon progeny, their unattached fraction (f(b)) and potential alpha energy concentration (E). These experimental data are measured using a low- pressure cascade impactor and a wire-screen diffusion battery. Because of the short half-lives of the investigated nuclides, modifications that simplify the dose calculation are possible. The radioactive aerosol and biological parameters are varied in order to assess the DCF arising from the uncertainty of these parameters. The main emphasis is on the variation of the ventilation rate, breathing mode, critical cells for the induction of lung cancer and the parameters of the attached and unattached activity size distribution of the radon progeny. The investigation shows that the DCF is more than a factor of two higher than the values recommended by the ICRp((2)) ,namely 3.9 mSv WLM-1 for the public and 5.1 mSv WLM-1 for working places. The dose results for indoor aerosol conditions are in the range 2.3-2.6 mSv WLM-1 depending on the breathing mode.