Vol. 91, Issue 2, 725-732, August 2001
Ozone absorption in the human nose during unidirectional
airflow
Lizzie Y.
Santiago1,
Matthew C.
Hann1,
Abdellaziz
Ben-Jebria1,2, and
James S.
Ultman1
1 Department of Chemical Engineering, Pennsylvania State
University, University Park, Pennsylvania 16802; and
2 Institut National de la Santé et de la Recherche
Médicale, Paris, France
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 (
) 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 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 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
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.
dosimetry; inhalation toxicology; nasal cavities; nasal
uptake; diffusion resistance; flow effect; concentration effect
