Ozone uptake in awake Sprague-Dawley rats.

Knowledge of ozone (O3) uptake in rats in integral to efforts to quantitatively extrapolate animal data to man. We have measured percentage O3 uptake in 30 adult Sprague-Dawley rats exposed, nose only, for 1 hr to 0.3, 0.6, or 1.0 ppm O3. Tidal volume and breathing rate measurements, obtained by plethysmography, were time-matched with changes in airstream concentrations of O3, oxygen, and carbon dioxide, due to animal breathing, for computation of O3 uptake and respiratory gas exchange values. Ozone uptake was calculated by a fractional deposition technique, i.e. O3 in vs O3 out. Total respiratory system O3 uptake was found to be approximately 40% of that inspired and did not vary with O3 concentration nor during the 1-hr exposure. The quantity of O3 inhaled and retained by the rat increased proportionally with O3 concentration.