EVALUATION OF THE VALIDITY ACID REPRODUCI BILITY OF PASSIVE OZONE MONITORS

The aim of this study was to evaluate the validity and reproducibility between ozone measurements obtained with passive ozone monitors and t hose registered with a continuous ozone monitor to determine the appli cability of passive monitors in epidemiological research. The study wa s carried out during November and December 1992. Indoor and outdoor cl assroom air ozone concentrations weve analyzed using 28 passive monito rs and using a continuous monitor The correlation between both measure ments was highly significant (r= 0.089, p< 0.001), indicating a very g ood validity. Also, the correlation between the measurements obtained with two different passive monitors exposed concurrently was very high (r= 0.97, p< 0.001), indicating a good reproducibility in the measure ments of the passive monitors. The relative error between the concentr ations measured by the passive monitors and those from the continuous monitor tended to decrease with increasing ozone concentrations. The r esults suggest that passive monitors should be used to determine cumul ative exposure of ozone exceeding 100 ppb, corresponding to an exposur e period greater than five days, if used to analyze indoor air.