Noninvasive determination of respiratory ozone absorption: The bolus-response method. Research report, July 1990-September 1992
The objective of the current research was to integrate into a bolus inhalation system capable of noninvasively measuring the longitudinal distribution of O3 absorption in intact human lungs. Ozone uptake was expressed as the amount of O3 absorbed during a single breath relative to the amount in the inhaled bolus. Measurements of ozone uptake were correlated with the penetration volume (Vp) of the bolus into the respiratory tract. During quiet oral breathing, ozone uptake increased smoothly with Vp, with 50% of the inhaled O3 absorbed in the upper airways and the balance absorbed within the lower conducting airways. The effect of increasing the respiratory flow, which occurs when people exercise, was to shift the ozone uptake-Vp distribution distally so that significantly less O3 was absorbed in the upper airways and more reached the respiratory airspaces. Compared with oral breathing, nasal breathing caused a proximal shift in the ozone uptake-Vp distribution to the extent that absorption in the upper airways increased from 50% to 80% flow. The peak O3 concentration of an inhaled bolus did not have a significant effect on the ozone uptake-Vp distributon. This implies that the diffusion and chemical reaction process dictating O3 absorption are linear.
- Research Organization:
- Health Effects Inst., Cambridge, MA (United States)
- OSTI ID:
- 71181
- Report Number(s):
- PB-95-213757/XAB; HEI/RR-69/94; CNN: Contract EPA-R-816285; TRN: 51702318
- Resource Relation:
- Other Information: PBD: Aug 1994
- Country of Publication:
- United States
- Language:
- English
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