The long-term objective of this study is to better understand the fate of inhaled particles in the human lung. Exposure to particulate matter (PM) has been a major concern in the recent years as more evidence links air pollution and mortality. A better understanding of aerosol deposition (DE) in the lung may also be beneficial in applications such as inhalation drug therapy. Mathematical models are often used to help interpret the experimental studies and to make predictions for cases where experimental data are not available. Aerosol transport in both symmetrical and asymmetrical two-dimensional models of the alveolar zone of the human lung will be simulated ro 0.5 to 5 mum particles is mainly due to gravitational sedimentation. The orientation of the structure with respect to the gravity vector is a major factor affecting DE patterns. CM causes inhaled particles to be irreversibly transferred to the resident air during their transport through the lung. Because of this transfer, some particles that do not deposit on the airway walls remain in suspension in the distal airways at the end of a normal expiration and fail to exit the lung. These particles then penetrate deeper in the lung during the next breath and eventually deposit. Velocity profiles in the alveolar region of the lung are expected to be a major factor that affects CM. The simulations will allow us to isolate their effect and to determine their contribution to overall CM. Finally the effects of extra CM caused by stretch and fold on the alveolar DE of particles in the human lung will be simulated. Stretch and fold refers to the process where, because of non-reversibility of flow in the lung, air streamlines become folded back on themselves, enhancing mixing. The results of this study may provide a link to the mechanisms by which even seemingly modest exposure to PM can cause or exacerbate lung disease. The results will also help to better design spatial targeting of drugs administered by inhalation therapy.
