Abstract-A laboratory system has been developed in which the atmosphere and fluid dynamics of the upper tracheobronchial (TB) tree of the human are simulated. It is used to measure the hygroscopic growth rates of monodisperse NaCl and bronchodilator (Isuprel® hydrochloride with and without glycerine) aerosols. Dry particles are mixed with water vapour-laden air at the entrance to a growth chamber temperature controlled at 37°C with a relative humidity (RH) between 88 and 95%. Hygroscopic growth rates increased with degree of RH and magnitude of Reynolds number in the chamber. The growth data are incorporated into an aerosol deposition model to calculate the effect of hygroscopic growth upon the dose distribution of medicinal aerosols in the human TB network. The model uses some original deposition formulae to compute particle deposition efficiencies. Calculations show that the rate of water vapour absorption within TB airways is an important factor affecting the fate of particles used in aerosol therapy.
NOMENCLATUREThe nomenclature used in the development of theoretical formulae is as follows: