The relationship between particle deposition in the anterior nasal passageand nasal passage characteristics

The objective of this study was to examine the effects of nasal passage cha racteristics on anterior particle deposition during cyclical breathing. For ty healthy, nonsmoking, adult subjects participated in this study. Nasal pa ssage characteristics such as nostril length, width, angle, ellipticity, an d minimum nasal cross-sectional area were measured. The subjects inhaled a polydisperse radioactively tagged aerosol (mass median aerodynamic diameter = 5.4 mu m, geometric standard deviation [GSD] = 1.3) into the nose and ex haled through the mouth. The amount of radioactivity in the nose was measur ed immediately after inhalation and thereafter for 54 minutes. At 52.5 minu tes, subjects wiped the accessible portion of the anterior nose to remove a ny remaining activity. The difference in activity at 52 and 54 minutes was used as a measure of activity removed during the nose wipe. Percentage of a ctivity in the nasal passage at 52 minutes and percentage of activity remov ed with the nose wipe were considered surrogates for particles deposited in the anterior nasal passage. A multiple regression analysis showed that the degree of ellipticity of the nostrils was significantly related to particl e deposition in the anterior nasal passage. These results suggest that elli pticity of the nostrils may be a determinant of the amount of particle depo sition in the anterior nasal passage.