Relationship between ozone exposure and pulmonary function changes.

A detailed comparison of literature-reported averaged decrements in pulmonary function of normal subjects exposed to O3 has been undertaken. The data base was formed by including data published during the past 20 yr from studies that reported at least one of the pulmonary function variables (forced vital capacity, forced expiratory volume at 1 s, mean forced expiratory flow between 25 and 75% of forced vital capacity, and airway resistance) acquired at 2 h of exposures utilizing either original or modified Bates-Hazucha (intermittent exercise) protocol and that satisfied selection criteria. The final set of data (24 studies involving 299 subjects) was divided by ventilation rate (exercise loads) into four categories: light, moderate, high, and very high ventilation level. For each pulmonary function variable and ventilation level a quadratic function has been fitted to the data using regression procedures. The curve parameter estimates have been computed, tabulated, and statistically evaluated. The slope (quadratic coefficient) for each variable within a group and almost all variables between groups were significantly different from zero and from each other at P less than or equal to 0.0001.