Measurement Strategies of Airborne Nanomaterials

Airborne nanomaterials have the potential to impact environmental, public, and occupational health. As such, background and incidental airborne nanomaterials are ubiquitous in both developed and emerging countries. Furthermore, increased application of engineered nanomaterials (ENMs) in consumer goods and research and development markets has led to a corresponding growth of nanomaterial-related manufacturing to meet this demand. As these sources are extremely diverse, opportunities for exposure to airborne nanomaterials are equally diverse. Environmental and occupational exposures to nanomaterials have the potential to occur if the material is not safely handled or the activity is not effectively contained. However, evaluating and assessing potential exposure to airborne nanomaterials pose new challenges due to their small size, their negligible mass, and their high diffusivities. In addition to continuing questions regarding such issues as selection of appropriate dose metrics (mass, surface area, or number) and the identification of physicochemical characteristics of nanomaterials that impact environmental and human health, sampling strategies may be necessary to identify any spatial and temporal changes in nanomaterial concentration and physicochemical characteristics while also differentiating incidental and ENMs from background nanomaterials. Currently, exposure assessment and routine monitoring for airborne nanomaterials are either very minimal or nonexistent. Whenever monitoring efforts occur, they do not generally follow any consistent strategy. However, strategies to conduct exposure assessments have begun to emerge. The goal of this article is to review sampling strategies and instrumentation characteristics needed to carry out industrial hygiene exposure assessments for airborne nanomaterials