Effect of flow rate on particle deposition in a replica of a human nasal airway.

Charge-coupled device (CCD) imaging technology was used to observe how the spatial deposition patterns of inhaled aerosols changed as a function of rate of airflow through the airway. This technology allows the experimenter to measure local particle deposition patterns of different sized fluorescent particles at different flow rates in a full-scale multisection replica of a human nasal airway. Total particle deposition efficiencies and particle deposition patterns were measured in the nasal airway for 5.5-microm-diameter particles at constant flow rates of 10, 20, 30, and 40 L/min. Images of fluorescing particles on each plate of the exposed model were taken with a CCD camera and combined to form three-dimensional particle deposition patterns. Total particle deposition efficiency as measured with the model was found to be consistent with in vivo data. Impaction was found to be the dominant mechanism by which 5.5-microm-diameter particles deposit within the model, in agreement with published inhalation data.