Experimental Ozone Dosimetry in Humans

ABSTRACT To extrapolate data on the acute pulmonary function response to ozone from controlled chamber studies to the general population in the ambient environment, well defined response functions are needed. These functions should depend upon ozone concentration, minute ventilation, and exposure time since these variables determine the dose of ozone to the respiratory tract. Successful development of dose-response functions has been impaired by the fact that pulmonary function response to ozone does not follow simple exposure dose-response relationships, where exposure dose is given by the product of concentration × time × minute ventilation. By analyzing data on the uptake of ozone in the human respiratory tract, and integrating it with a mathematical model of ozone uptake, we demonstrate why exposure dose-response relationships are inadequate. We further demonstrate that the relevant dose that may be predictive of ozone induced spirometric decrements is the dose to the tracheobronchial airways. In addi...