Noninvasive determination of ozone distribution in the human lung airways
The response of lung epithelium to ozone exposure depends on cell sensitivity as well as on delivered dose. Because lung damage by ozone is site-specific, it was the main objective of this study to develop and utilize a bolus-response method for the noninvasive determination of longitudinal ozone distribution in the human lung. Ozone transport in a rigid single-pathway anatomic model of the lung was simulated numerically by the method of orthogonal collocation on finite elements to predict the data that would be obtained in human subjects. The simulation results provided evidence supporting the safety of the bolus-response technique. A bolus-response inhalation system including a fast-responding chemiluminescent O[sub 3] analyzer and a small-scale O[sub 3] bolus generator was specifically developed for this project. Measurements of ozone absorption were carried out on nine healthy male subjects at a constant inspiratory and expiratory flow of 250 m[ell]/sec as well as elevated respiratory flows ranging from 150 to 1,000 m[ell]/sec. By evaluating the mathematical moments of the inspired bolus and expired response data, the fraction of inhaled ozone that was absorbed was computed in the first 200 m[ell] of the human lung. The resulting data indicated that under quiet breathing conditions, the fraction of inhaled O[sub 3] absorbed by the upper airways is roughly 50%. By increasing the respired flow from 150 to 1,000 m[ell]/sec, the fraction of ozone absorbed into upper airways decreased from 65 to 15%. Virtually all of the remaining O[sub 3] was absorbed in the lower airways.
- Research Organization:
- Pennsylvania State Univ., University Park, PA (United States)
- OSTI ID:
- 6968259
- Resource Relation:
- Other Information: Thesis (Ph.D.)
- Country of Publication:
- United States
- Language:
- English
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LUNGS
RETENTION FUNCTIONS
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COMPUTERIZED SIMULATION
EXPERIMENTAL DATA
INHALATION
MAN
RESPIRATION
UPTAKE
ANIMALS
BODY
DATA
DISTRIBUTION
FUNCTIONS
INFORMATION
INTAKE
MAMMALS
NUMERICAL DATA
ORGANS
PRIMATES
RESPIRATORY SYSTEM
SIMULATION
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560300* - Chemicals Metabolism & Toxicology