Understanding workplace processes and factors that influence exposures to engineered nanomaterials.

There is a critical need to understand the factors that influence engineered nanomaterial (ENM) exposures in the workplace. Such an understanding would aid in: identifying and prioritizing control measures; targeting future exposure measurements; and predicting worker exposures for work scenarios. This information could also be used in epidemiological studies. We propose a multitiered model in which information on exposure factors can be obtained at the macrolevel (examining differences in exposures between different ENM sectors or product types); the midlevel (examining differences in exposures between workplaces within the same ENM sector or product type); and the microlevel (examining differences in exposure between tasks or between ENM types during the same task). Further, within the microlevel, potential exposure factors are defined by a source-receptor model. We recommend that auxiliary data be collected systematically, along with exposure measurements, to enable analysis of exposure factors as well as the pooling of data across studies.