Background: In this study, we describe the methodology used for historical estimation of exposure to fluoride and to PAH in vertical stud Søderberg (VSS) potrooms at two Norwegian aluminum smelters. The assessment was performed in order to develop exposure data for epidemiological studies of cause-specific mortality and cancer incidence.
Methods: The estimation was performed in several steps. In the first step, we estimated the area concentrations of fluoride and PAH in periods with no measurements. Relationships between measured area concentrations and process parameters were investigated by statistical modeling. Process parameters and the models were then used to estimate area concentrations in periods lacking area measurement data. In the second step, the relationships between the area measurements and job specific exposure (personal measurements) were investigated by use of a measurement model. In the last step, the obtained relationships were used to estimate job specific exposure in different periods.
Results: The range for the annual exposure estimates in the VSS-potrooms was 0.05-1.7 mg/m3 for fluoride and 3-3,437 micrograms/m3 for PAH.
Conclusions: Despite limitations of available measurements in the early production period, we have concluded that the exposure estimates from this study provide a reasonable tool for the estimation of dose-response relations in subsequent epidemiological analyses.