NASOPHARYNGEAL REMOVAL OF OZONE IN RABBITS AND GUINEA-PIGS

In estimating pollutant concentrations responsible for observed pulmonary effects, nasopharyngeal removal of the pollutant plays an important role. The nasopharyngeal removal of ozone (O3) in anesthetized male guinea pigs and male and female rabbits was determined by drawing O3 through the isolated upper airways at a constant flow rate which approximated the animal's respiratory minute volume. The tracheal O3 concentration in rabbits and guinea pigs was markedly similar was linearly related to the chamber concentration of O3 over a range of 196-3920 μg/m3 (0.1-2.0 ppm O3). Regression analyses showed that O3 removal in the nasopharyngeal region is approximately 50% in both species. Both rabbit sexes responded similary over the concentration range studied. Exposures of guinea pigs to O3 concentrations between 3920 and 5880 μg/m3 (2.0 and 3.0 ppm) showed that, at these higher concentrations, relatively more O3 is removed by the upper airways. © 1979.