Aerosol deposition along the respiratory tract at zero gravity: a theoretical study
Significant fractions of airborne particles composing inhaled aerosols can deposit along the respiratory tract during breathing. Depending on the environmental condition, some particles that enter the body via the respiratory route can pose health hazards. On earth, three general rate mechanisms are active in this deposition process: (1) inertial impaction; (2) diffusion; and (3) gravity-dependent sedimentation. Space craft, stations, and bases represent unique settings where potentially pathogenic aerosols may be encountered under the unique condition of zero or reduced gravity. The present study was undertaken in order to predict how particle deposition in the human respiratory tract at zero gravity may differ from that on earth. We employed the aerosol deposition model of the Task Group on Lung Dynamics to assess the regional deposition of particles ranging from 0.01 to 10 ..mu..m diameter at two particulate densities, 1 and 4, during simulated tidal breathing and breathing during moderate - heavy exercise. Our results suggest the gas exchange regions of the lungs of space travelers and residents are afforded some protection, relative to their earth-bound counterparts, against the deposition of particles due to the absence of gravity; and approximately 2 to 10 fold reduction in the efficiency of collection of particles > 0.5 ..mu..m in diameter occurred in the pulmonary region during resting conditions and exercise. Deposition along the tracheobronchial tree, however, is not markedly altered in the absence of gravity, indicating airway sites contributing to this structure remain susceptible to insults by inhaled aerosols. 18 references, 2 figures, 2 tables.
- Research Organization:
- Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
- DOE Contract Number:
- W-7405-ENG-36
- OSTI ID:
- 6051411
- Report Number(s):
- LA-UR-85-362; CONF-8410230-1; ON: DE85006703
- Resource Relation:
- Conference: Lunar bases and space activities of the 21st century, Washington, DC, USA, 29 Oct 1984; Other Information: Portions are illegible in microfiche products
- Country of Publication:
- United States
- Language:
- English
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AEROSOLS
DEPOSITION
WEIGHTLESSNESS
RESPONSE MODIFYING FACTORS
LUNGS
MAN
SIMULATION
SPACE FLIGHT
ANIMALS
BODY
COLLOIDS
DISPERSIONS
MAMMALS
ORGANS
PRIMATES
RESPIRATORY SYSTEM
SOLS
VERTEBRATES
560306* - Chemicals Metabolism & Toxicology- Man- (-1987)