Deposition and clearance of inhaled particles
Theoretical models of respiratory tract deposition of inhaled particles are compared to experimental studies of deposition patterns in humans and animals, as governed principally by particle size, density, respiratory rate and flow parameters. Various models of inhaled particle deposition make use of approximations of the respiratory tract to predict fractional deposition caused by fundamental physical processes of particle impaction, sedimentation, and diffusion. These models for both total deposition and regional (nasopharyngeal, tracheobronchial, and pulmonary) deposition are compared with early and recent experimental studies. Reasonable correlation has been obtained between theoretical and experimental studies, but the behavior in the respiratory tract of very fine (<0.1 ..mu..m) particles requires further investigation. Properties of particle shape, charge and hygroscopicity as well as the degree of respiratory tract pathology also influence deposition patterns; definitive experimental work is needed in these areas. The influence upon deposition patterns of dynamic alterations in inspiratory flow profiles caused by a variety of breathing patterns also requires further study, and the use of differing ventilation techniques with selected inhaled particle sizes holds promise in diagnosis of respiratory tract diseases. Mechanisms of conducting airway and alveolar clearance processes involving the pulmonary macrophage, mucociliary clearance, dissolution, transport to systemic circulation, and translocation via regional lymphatic vessels are discussed.
- Research Organization:
- Air Force Aerospace Medical Research Lab., Wright Patterson Air Force Base, OH
- OSTI ID:
- 5118627
- Journal Information:
- Environ. Health Perspect.; (United States), Vol. 55
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
PARTICULATES
DEPOSITION
LUNG CLEARANCE
RETENTION
ANIMALS
BIOLOGICAL FUNCTIONS
INHALATION
MACROPHAGES
MAN
MATHEMATICAL MODELS
PARTICLE SIZE
RESPIRATORY SYSTEM
THEORETICAL DATA
ANIMAL CELLS
CLEARANCE
CONNECTIVE TISSUE CELLS
DATA
EXCRETION
FUNCTIONS
INFORMATION
INTAKE
MAMMALS
NUMERICAL DATA
PARTICLES
PHAGOCYTES
PRIMATES
SIZE
SOMATIC CELLS
VERTEBRATES
560306* - Chemicals Metabolism & Toxicology- Man- (-1987)
560305 - Chemicals Metabolism & Toxicology- Vertebrates- (-1987)