Measurement, testing, and characterization of airborne nanoparticles released from machining of nanoreinforced composites

Abstract Nanoenhanced products are widely being established within industry due to, among others, their lightweight, performance advantages, and ability to meticulously target material properties with great control and precision. Despite the beneficial properties introduced, certain nanofillers have shown conceivable health risks and toxicity to humans and the environment. It is important to fully understand the toxicity associated with nanomaterials, as well as to acknowledge that throughout their lifecycle, nanocomposites will undergo energy input that has the potential for the unintentional release of the particles. A full understanding of the inadvertent release of nanoparticles within the workplace poses unknown risks that are yet to be quantified. So far, however, there is no harmonized conclusion on the particles released and no standardized method established to simulate the release scenarios. While in some cases, synthesis of nanoparticles has shown to not present evidence of clear nanoparticle exposure, processes of high energy input have provided evidence that inhalation exposure occurs. Although the various test guidelines and reports on exposure assessments have made remarkable progress and are available to assist in carrying out an adequate approach, there is no available standard or harmonized method in assessment of nanomaterial release during lifecycle scenarios, particularly machining. The approach, measurement, and sampling techniques used to measure the same release or exposure characteristics can differ quite significantly. Governing bodies are attempting to collate the best methods to help simplify the approach; however, these are currently difficult as not one technique is sufficient to evaluate the release. The guidelines, reports, and frameworks are discussed and have provided a significant set of beneficial principles to follow but emphasize the current lack in a harmonized approach. Due to the variation in approaches reported within literature, this chapter will review the approaches, measurement, and sampling techniques in use.