Estimation of deposition of polydisperse hygroscopic aerosols in the human respiratory tract

Regional deposition of an arbitrary hygroscopic material is estimated by interpolation of deposition efficiencies previously calculated using a hygroscopic particle lung deposition(HPLD) model by Ferron et al. for spheres of NaCl, ZnSO4&middot7H2O and a non-hygroscopic material in the range of 0. 1 and 10 μm aerodynamic diameter. The interpolation is performed for the aerodynamic growth factors of the materials for each individual airway generation. A polydisperse size distribution is simulated by using discrete monodisperse fractions. Applying the estimation method to the deposition is simulated by using discrete monodisperse CoCl2.6H2O particles, deposition differs by less than 13% from the values obtained from the HPLD model. Two modifications of the estimation model are described: one using the equivalent growth factor instead of the aerodynamic growth factor and the other using the deposition efficiencies of NaCl and a non-hygroscopic material instead of the three materials mentioned above. The first modification gives similar results and the second modification gives larger differences up to 20% if compared with the deposition efficiencies obtained with the HPLD model. The estimation method is easier to handle than the HPLD model.