Flour dust exposure variability in flour mills and bakeries

As part of a longitudinal study to explore the exposure-response relationship between flour dust exposure and work-related symptoms and skin sensitivity the authors formed exposure groups and estimated various components of variability. This paper describes the between-exposure group, the between-worker and the within-worker variation of personal flour dust exposure in bakeries, flour mills and packing stations. In total 346 samples were collected in 13 exposure groups. The geometric means of the exposure groups ranged from 0.3 up to 9.0 mg m-3. Between-worker variances within exposure groupings were less than the overall between-worker component although substantial differences in exposure between workers remained in some exposure groups. Overall the largest variance component was the between-exposure group component followed by the considerably smaller between-worker and within-worker components.