1 Radon Characteristics Related to Dose for Different Living Places of the Human

Inhalation of the short-lived radon decay products, 218Po, 214Pb, 214Bi/214Po, in homes, in the outdoor atmosphere and at work places yield the greatest amount of the natural radiation exposure of the human. In all dosimetric models the dominant parameter related to dose is the activity size distribution of the decay products in the air because the original deposition destination and amount of the inhaled activity deposited in lung depend on the particle size. For the determination of dose a relation between the potential alpha energy concentration of the radon progeny exposure (Cp t) and dose the so-called dose conversion factor (DCF = Dose/Cp t) is needed. Cp is the potential alpha energy concentration (PAEC) of the short-lived radon decay products, and t is the time of inhalation. In the estimation of the DCF by dose model calculations the activity size distribution in terms of potential alpha energy concentration is an important input parameter. For practical reasons related to measurements the relative activity size distribution should be divided into • relative size distribution of the unattached radon progeny, • relative size distribution of the radon progeny aerosol, • the unattached fraction in terms of potential alpha energy concentration (fp). In the following paper, the values of these three quantities, their variation and the main influencin