Age-related scaling for aerosol and vapor deposition in the upper airways of humans.
Several theoretical models have been proposed in recent years to calculate age-related respiratory tract deposition of aerosols in humans. A critical factor in these models is the assumption about deposition in the airways above the trachea. In those models in which upper airway deposition is considered, a scaling factor, related to another airway dimension (usually tracheal diameter), is used to calculate an upper-airway dimension which determines inertial deposition. The paper reviews present knowledge of upper airway dimensions and airflow and proposed an age-related relationship for the critical nasal dimension, the nasal orifice. Relative inertial parameters for breathing at rest are obtained as a function of age from 1 mo to adulthood and compared to previous assumptions. The use of dimensionless parameters for predicting age-related deposition of diffusing particles and vapors is considered, and suggested experimental studies are proposed to supply needed information for age-related dosimetry of the entire respiratory tract.
Swift
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DL
Johns Hopkins University, Baltimore, MD 21205.
D000336:Aerosols; D000375:Aging; D002675:Child, Preschool; D005740:Gases; D006801:Humans; D007223:Infant; D008954:Models, Biological; D012137:Respiratory System / Q000254:growth & development*
D000336:Aerosols; D005740:Gases