ABSTRACT
In toxicology studies, often a large mass of powder is available and the physicochemical properties are characterized using pristine material rather than actual workplace exposure particles. Given the importance of the inhalation route of exposure for engineered nanomaterials (ENM), this chapter reviews approaches to occupational inhalation exposure assessments for airborne ENMs in workplaces and discusses relevant metrics for exposure and toxicity. When the initial exposure assessment studies for ENMs were conducted in the early 2000s, there was little understanding of toxicological mechanisms for adverse health effects. There are many real-time and time-integrated techniques available to characterize various metrics of ENM exposure in occupational settings; a combination of both types of techniques is almost always necessary to discriminate an ENM of interest from incidental nanoparticles in workplace atmospheres. Dermal exposures may also be a relevant pathway for ENMs, although there are no occupational exposure limits for skin exposure and few standardized monitoring approaches.
