Departmental Papers (BE)

Document Type

Journal Article

Date of this Version

February 2006

Comments

Postprint version. This is a pre-copy-editing, author-produced PDF of an article accepted for publication in Chemical Senses following peer review. The definitive publisher-authenticated version in Volume 31, Issue 2, Feb 2006, pages 107-118, is available online at:
Publisher URL: http://dx.doi.org/10.1093/chemse/bjj008

Abstract

Human sniffing behavior usually involves bouts of short, high flow rate inhalation (>300 ml/s through each nostril) with mostly turbulent airflow. This has often been characterized as a factor enabling higher amounts of odorant to deposit onto olfactory mucosa than for laminar airflow and thereby aid in olfactory detection. Using computational fluid dynamics human nasal cavity models, however, we found essentially no difference in predicted olfactory odorant flux (g/cm2 s) for turbulent versus laminar flow for total nasal flow rates between 300 and 1000 ml/s and for odorants of quite different mucosal solubility. This lack of difference was shown to be due to the much higher resistance to lateral odorant mass transport in the mucosal nasal airway wall than in the air phase. The simulation also revealed that the increase in airflow rate during sniffing can increase odorant uptake flux to the nasal/olfactory mucosa but lower the cumulative total uptake in the olfactory region when the inspired air/odorant volume was held fixed, which is consistent with the observation that sniff duration may be more important than sniff strength for optimizing olfactory detection. In contrast, in rats, sniffing involves high-frequency bouts of both inhalation and exhalation with laminar airflow. In rat nose odorant uptake simulations, it was observed that odorant deposition was highly dependent on solubility and correlated with the locations of different types of receptors.

Keywords

laminar nasal airflow, odorant uptake modeling during sniff, olfactory odorant uptake, turbulent nasal airflow

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Date Posted: 26 January 2007

This document has been peer reviewed.