Theoretical foundation for a simple method for simultaneous measurements of the unattached fraction and activity median diameter of attached radon progeny

Calculation of lung dose from established lung dosimetry models requires us e of the unattached fraction of potential alpha energy concentration (PAEC) of radon progeny and the activity median diameter (AMD) of attached radon progeny, in addition to the total PAEC. In the present work, for indoor env ironments without the nucleation mode of aerosols, a method based on the wi re screen penetration theory using two wire screens and a filter is propose d for simultaneous measurements of these two parameters. It is shown that t he traditional wire screen method can overestimate or sometimes underestima te the unattached fraction, depending on the properties of the wire screen and the true unattached fraction. The present method eliminates such uncert ainties. (C) 2001 Elsevier Science Ltd. All rights reserved.