MASS-TRANSPORT MODELS TO PREDICT TOXICITY OF INHALED GASES IN THE UPPER RESPIRATORY-TRACT

Mass transport (the movement of a chemical species) plays an important role in determining toxic responses of the upper respiratory tract (U RT) to inhaled chemicals. Mathematical dosimetry models incorporate ph ysical characteristics of mass transport and are used to predict quant itative uptake (absorption rate) and distribution of inhaled gases and vapors in the respiratory tract. Because knowledge of dose is an esse ntial component of quantitative risk assessment, dosimetry modeling pl ays an important role in extrapolation of animal study results to huma ns. A survey of existing mathematical dosimetry models for the URT is presented, limitations of current models are discussed, and adaptation s of existing models to produce a generally applicable model are sugge sted. Reviewed URT dosimetry models are categorized as early, lumped-p arameter, and distributed-parameter models. Specific examples of other relevant modeling work are also presented.