PREDICTION OF OZONE-INDUCED FEV1 CHANGES - EFFECTS OF CONCENTRATION, DURATION, AND VENTILATION

The purpose of this analysis of previously published data was to ident ify a model that accurately predicts the mean ozone-induced FEV1 respo nse of humans as a function of concentration (C), minute ventilation ( (V) over dotE), duration of exposure (T), and age. Healthy young adult s (n = 485) were exposed for 2 h to one of six ozone concentrations wh ile exercising at one of three levels. Candidate models were fitted to portions of the data and evaluated on the basis of their ability to p redict the mean response of independent samples. A sigmoid-shaped mode l that is consistent with previous observations of ozone exposure-resp onse (E-R) characteristics was identified and found to accurately pred ict the mean response with independent data. This model in a more gene ral form may allow the prediction of responses under conditions of cha nging C and (V) over dotE. We did not find that response was more sens itive to changes in C than in (V) over dotE, nor did we find convincin g evidence of an effect of body size upon response. We did find that r esponse to ozone decreases with age. In summary, we have identified a biologically plausible, predictive model that quantifies the relations hip between the ozone-induced change in FEV1, and C, (V) over dotE, T, and age.