Longitudinal distribution of ozone absorption in the lung: Effects of respiratory flow

Journal Article · Mon Aug 01 04:00:00 EDT 1994 · Journal of Applied Physiology

OSTI ID:50641

Hu, S C; Ben-Jebria, A; Ultman, J S ^[1]

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1. Pennsylvania State Univ., University Park, PA (United States)

In previous work, the authors developed a bolus inhalation apparatus and measured the longitudinal distribution of ozone (O{sub 3}) uptake in intact human lungs at a quiet respiratory flow of 250 ml/min. The objective of the present study was to determine the effect of alternative respiratory flows between 150 and 1,000 ml/s. Uptake was expressed as the O{sub 3} absorbed during a single breath relative to the amount of O{sub 3} in the inhaled bolus ({Lambda}). Measurements of {Lambda} were correlated with the penetration volume of the bolus into the respiratory tract (Vp). Vp in the range of 20-70 ml was considered to indicate upper airways (UA), the Vp interval of 70-180 ml was identified as lower conducting airways (CA), and Vp > 180 ml was associated with the respiratory air spaces (RA). During quiet oral breathing at 250 ml/s, {Lambda} increased smoothly as Vp increased, with 50% of the inhaled O{sub 3} absorbed in the UAs and the remainder absorbed within the CAs such that no O{sub 3} reached the RAs. The effect of increasing the respiratory flow was to shift the {Lambda}-Vp distribution distally such that significantly less O{sub 3} was absorbed in the UAs and CAs and some O{sub 3} reached the RAs. For example, at 1,000 ml/s, only 10% of the inhaled O{sub 3} was absorbed in UAs and 65% was absorbed in the CAs such that 25% reached the RAs. Further analysis of these data with a mathematical diffusion model suggested that the reaction between O{sub 3} and biochemical substrates is so fast (i.e., estimated 1st-order rate constant was on the order of 10{sup 6} s{sup {minus}1}) that O{sub 3} is decomposed close to the gas-mucus interface in the CAs. 24 refs., 7 figs., 3 tabs.

• OSTI ID: 50641
• Journal Information: Journal of Applied Physiology, Journal Name: Journal of Applied Physiology Journal Issue: 2 Vol. 77; ISSN JAPHEV; ISSN 8750-7587
• Country of Publication: United States
• Language: English

Related Subjects

56 BIOLOGY AND MEDICINE
APPLIED STUDIES
ABSORPTION
FLOW RATE
INHALATION
OZONE
SPATIAL DISTRIBUTION
UPTAKE