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Evaluation of facial features on particle inhalation.

Authors
Anthony-TR; Flynn-MR; Eisner-A
Source
Ann Occup Hyg 2005 Mar; 49(2):179-193
NIOSHTIC No.
20028696
Abstract
Computational fluid dynamics (CFD) and numerical investigations of particle inhalability and contaminant exposure have used simple geometrical surrogates for a breathing human form, but the effect of eliminating facial features has not been investigated. In this work, the velocity field and particle aspiration associated with two differently shaped mannequins were investigated to determine if an elliptical form was sufficient to represent the complexity of fluid flow associated with an inhaling human. Laser Doppler anemometry was used to measure velocity, and both optical sizing and gravimetric analysis were used to measure particle aspiration from an aerosol source. All tests were performed with continuous inhalation through the mouth, with the mannequin facing the 0.3 m s(-1) freestream. Although limitations in the laser Doppler optics prevented velocity measurements at distances <11 mm in front of the mannequin mouth opening, significant velocity differences were identified up to 20 mm in front of the mouth opening. This indicated that facial features affected the flow field near the face only. Owing to these differences, particle aspiration was compared between mannequins for three different velocity ratio conditions using an aerosol source. Even with relatively large variability in the aspirated concentration in this study, the aspirated mass concentration was significantly less for the anatomical mannequin relative to the elliptical form. Thus, the simplified elliptical cylinder does not sufficiently characterize the fluid dynamics near the mouth of an inhaling human form at these limited test conditions. Future CFD and numerical simulations to investigate human aspiration of particles should incorporate the complex features of the human face to investigate adequately particle aspiration in low velocity environments.
Keywords
Particulates; Inhalation-studies; Airborne-particles; Air-contamination; Exposure-levels; Humans; Gravimetric-analysis; Aerosols; Aerosol-particles
Contact
Department of Environmental Sciences and Engineering, UNC, School of Public Health, 118 Rosenau Hall, CB 7431, Chapel Hill, NC 27599-7431, USA
CODEN
AOHYA3
Publication Date
20050301
Document Type
Journal Article
Email Address
reneecih@email.unc.edu
Funding Amount
719405
Funding Type
Grant
Fiscal Year
2005
NTIS Accession No.
NTIS Price
Identifying No.
Grant-Number-R01-OH-007363
Issue of Publication
2
ISSN
0003-4878
Priority Area
Research Tools and Approaches: Exposure Assessment Methods
Source Name
Annals of Occupational Hygiene
State
NC
Performing Organization
University of North Carolina Chapel Hill
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