DEPOSITION OF RADON DAUGHTERS IN HUMANS EXPOSED TO URANIUM MINE ATMOSPHERES

Uranium mine and laboratory experiments are described for the determination of total respiratory deposition of radon daughters together with the effect of particle size, tidal volume, respiratory frequency, nasal deposition and growth of radon daughter particle size. Total respiratory deposition of radon daughters measured in humans exposed in uranium mines was found to range from 23% to 45%. From the mine and laboratory experiments, both particle size and tidal volume were found to influence deposition, fractional deposition increasing with decreasing particle size and increasing tidal volume. Particle size differed with location within a mine. No dependence of deposition on respiratory frequency or minute volume was discerned. In laboratory experiments, nasal deposition of attached and unattached radon daughters was found to be 2% and 62%, respectively, and evidence was developed indicating the rapid growth of radon daughter particles in the respiratory tract. © 1969 Health Physics Society.