Modeling Deposition of Inhaled Particles - Aerosols: Measurement, Dosimetry, and Health Effects - page 112

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FIGURE 5.15 Model predictions of TB deposition determined using the deterministic model of Martonen, 7,31
plotted against experimental data. 281 (A) Breathing frequency = 30 breaths/min, tidal volume = 500 mL, (B)
breathing frequency = 15 breaths/min, tidal volume = 1000 mL, and (C) breathing frequency = 30 breaths/min,
tidal volume = 1500 mL.

in validating CFPD methods. For example, Kim and Fisher 294 described deposition in a series of
physical tubes. Their results have been used to validate the CFPD models of Farkas et al., 295 which
were performed in geometrically similar conigurations.

5.5.3.2.3 Pulmonary
Hofmann and Koblinger 282 also compared their simulated pulmonary deposition values with the
experimental data of Heyder et al. 283 ; their model very closely predicted measured values in the
pulmonary region. Results from the deterministic model of Martonen 7,32 for the pulmonary region
are plotted against the experimental data of Heyder et al. in Figure 5.16. While generally good
agreement was seen between theory and experiment over the particle sizes simulated, there was a
noticeable shift of the predicted deposition with respect to the experimental data. Such a systematic
trend in the model bears further investigation.

5.5.3.3 Simulations of Particle Distribution Generation-by-Generation
Figure 5.17 depicts particle deposition by generation as predicted by the model of Martonen 7,32 for a
variety of ventilatory conditions. At higher low rates (Figure 5.17C), the model predicts enhanced
deposition of large particles in the TB airways. Experimental measurements of deposition genera-
tion-by-generation are scarce, and additional accurate cast studies would be particularly useful in
validating such simulations.

5.5.3.4 Simulations of Local Particle Deposition
Experimental data describing the local airway concentrations of inhaled particles are relatively
scarce, and are mainly derived from observations of cadaver airways and cast studies. Therefore, it
is challenging to validate CFPD studies of local particle deposition in all except very simple geom-
etries, although predicted accumulations of particles at carinal ridges have been shown consistent
with experimental observations. 53 Recent efforts by Martonen et al. 279,280 present a methodology for