Ozone absorption in the human nose during unidirectional airflow.
Santiago, Lizzie Y., Matthew C. Hann, Abdellaziz Ben-Jebria, and James S. Ultman.
1Department of Chemical Engineering, Pennsylvania State University, University Park, Pennsylvania 16802; and 2Institut National de la Santé et de la Recherche Médicale, Paris, France
APStracts 8:0276A, 2001.
This study addresses the effect of gas flow rate and ozone (O3) concentration on the uptake of this air pollutant in the nose. A nasal exposure system was developed in which a constant flow of humidified air ("odot"V) containing a constant concentration of O3 (Cinlet) entered one nostril and then exited the other nostril while a subject closed the velopharyngeal aperture. Experiments were conducted on 10 healthy nonsmokers for whom O3 concentration was alternatively measured at the inlet nostril and the outlet nostril to determine the fraction of inhaled O3 that was absorbed into the nasal mucosa (?nose). ?nose decreased from 0.80 ± 0.02 to 0.33 ± 0.02 (SE) when "odot"V was increased from 3 to 15 l/min and Cinlet was fixed at 0.4 ppm. Analysis of these data with a mathematical model indicated that O3 uptake was limited by diffusion reaction through mucus, rather than by convective diffusion through the respired gas. A small decrease in ?nose from 0.36 ± 0.02 to 0.32 ± 0.01 was also observed when Cinlet was increased from 0.1 to 0.4 ppm at a fixed "odot"V of 15 l/min. This may have been due to nonlinear reaction kinetics between O3 and reactive substrates in mucus or an active response by a physiological process such as mucus secretion or transepithelial water influx.
Received 19 September 2000; accepted in final form 15 March 2001
APS Manuscript Number A937-0.
Article publication pending J Appl Physiol
ISSN 1080-4757 Copyright 2001 The American Physiological Society.
Published in APStracts on 18 June 2001