Regional deposition of inhaled fog droplets: preliminary observations
The regional deposition of a monodisperse 10-micron mass median aerodynamic diameter fog was studied in four healthy adult male nonsmokers. The fog was radiolabeled with technetium-99m sulfur colloid to enable detection by an Anger camera of deposited activity in the following regions of the respiratory tract: oropharynx, larynx, trachea, and intrapulmonary airways. Intrapulmonary deposition was further analyzed by computer with inner, intermediate, and outer zones, and within apical, intermediate and basal zones of the right lung. The radiolabeled aerosol was inhaled by mouth through a face-mask with the nasal airway occluded. Respiratory frequency, tidal volume, and jaw position were controlled and were commensurate with the oral component of oronasal breathing during moderate exercise. Deposition in the larynx, trachea, and intrapulmonary airways was a function of the scrubbing efficiency of the oropharynx, which differed substantially among subjects, and ranged from 72 to 99%. The density of the aerosol deposit in the larynx probably exceeded that of any of the subdivisions of the tracheobronchial tree and lung. Within the lung, deposition favored the inner zone (assumed to contain the larger airways) over the outer zone (assumed to be dominated by smaller airways and alveoli). Intrapulmonary aerosol distribution in an elderly subject with borderline evidence of airway obstruction differed from that observed in younger subjects. The possible consequences of altered lung elastic recoil, as may occur with aging, for regional dosimetry is discussed.
- Research Organization:
- Johns Hopkins School of Hygiene and Public Health, Baltimore, MD (USA)
- OSTI ID:
- 6071560
- Journal Information:
- Environ. Health Perspect.; (United States), Vol. 79
- Country of Publication:
- United States
- Language:
- English
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59 BASIC BIOLOGICAL SCIENCES
ACID RAIN
HEALTH HAZARDS
FOG
INHALATION
RESPIRATORY SYSTEM
SENSITIVITY
AEROSOLS
AGE DEPENDENCE
AIR POLLUTION
COLLOIDS
EXERCISE
ISOMERIC NUCLEI
MAN
RETENTION
TECHNETIUM 99
TRACER TECHNIQUES
ANIMALS
ATMOSPHERIC PRECIPITATIONS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
DISPERSIONS
HAZARDS
HOURS LIVING RADIOISOTOPES
INTAKE
INTERMEDIATE MASS NUCLEI
ISOMERIC TRANSITION ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
MAMMALS
NUCLEI
ODD-EVEN NUCLEI
POLLUTION
PRIMATES
RADIOISOTOPES
RAIN
SOLS
TECHNETIUM ISOTOPES
VERTEBRATES
YEARS LIVING RADIOISOTOPES
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