A measurement system for Rn decay product lung deposition based on respiratory models

Using models of particle deposition in the nasal cavity and in the tracheobronchial region of the respiratory tract, it is possible to design a measurement system based on wire screen penetration theory. This system provides direct estimates for the quantities of Rn decay product activity deposited in the nasal cavity and in the tracheobronchial region. Historically, measurements of the "unattached" fraction of the airborne Rn decay product size distribution have been made in order to better estimate the dose resulting from the deposition of these 222Rn progeny in the human respiratory tract. However, previous measurement systems have been developed based on choices of screen parameters and sampling flow conditions in an attempt to separate the "unattached" fraction from the rest of the activity size distribution. By taking into consideration the deposition behavior of particles in the respiratory tract, a specific choice of wire screens and flow rates can be made that can provide better information for the estimation of deposited dose in the respiratory tract.