A Modelling Study of Regional Deposition of Inspired Aerosols with Reference to Dosimetric Assessments

Abstract

An improved lung deposition model, whose predictions have been found to agree well with a wide range of total and regional deposition data, was used to investigate some of the assumptions embodied in current ICRP recommendations. Following a comparison between the predictions of the new model and the original ICRP Task Group deposition model, the possible influence upon dosimetric calculations caused by various different effects were investigated. Some significant differences between the regional deposition predictions of the new model and the current ICRP recommendations embodied in Publication 30 were found, up to a factor of ∼ 4 in some cases. The impact of the improved modelling, aerosol polydispersity, the possibility of mouth as compared to nose breathing and exercise level (especially if there is transition from nose to mouth breathing at high work rates) were observed to be the most important contributors. The impact of different breathing patterns was found to be less significant while the effect of different particle densities could be relatively successfully accounted for via a suitable transition from geometric to aerodynamic diameter.