An experimental study of clearance of inhaled particles from the human nose

J. R.H. Smith, Michael Bailey, George Etherington, A. L. Shutt, M. J. Youngman

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    9 Citations (Scopus)


    Retention in the extrathoracic airways, and clearance by nose blowing, of monodisperse indium-111-labeled polystyrene particles were followed for at least 2 days after inhalation by healthy volunteers. Nine volunteers inhaled 3-μm aerodynamic diameter particles while sitting at rest, whereas subgroups of 3 or 4 inhaled 1.5-μm or 6-μm particles at rest, and 3-μm or 6-μm particles while performing light exercise. Retention of the initial extrathoracic deposit (IETD) in the extrathoracic airways was described by 4 components: on average 19% IETD cleared by nose blowing; 15% was swallowed before the first measurement, a few minutes after inhalation; 21% cleared by mucociliary action between the first measurement and about an hour later; and 45% subsequently cleared by mucociliary action. Geometric mean times in which 50% and 90% of IETD cleared were 2.5 and 22 hours. The geometric mean retention fractions at 24 and 48 hours were 7% and 2.4% IETD, respectively. No clear trends were found between parameters describing retention and any related to deposition (e.g., particle size). However, the fraction cleared by nose blowing was related to the frequency of nose blowing and therefore appears to be a characteristic of the individual.

    Original languageEnglish
    Pages (from-to)109-129
    Number of pages21
    JournalExperimental Lung Research
    Issue number2
    Publication statusPublished - Mar 2011

    Bibliographical note

    Funding Information:
    The authors wish to express their appreciation to the volunteers for their invaluable cooperation. This study was partly funded by the European Commission under Contract Number F14P CT950026 “Inhalation of Radionuclides.” Mr. M. V. Holding is thanked for his assistance in developing and constructing equipment for the study. Address correspondence to Dr. Jennifer Smith, Health Protection Agency, Centre for Radiation Chemical and Environmental Hazards, Chilton, OX11 0RQ, UK. E-mail:


    • mucociliary clearance
    • nasal deposition
    • nasal retention
    • nose blow
    • volunteer inhalation study


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