Comparison of occupational exposure assessment tools and concepts for nanomaterials

The development, production and application of engineered nanomaterials have been growing in different fields. This leads to a consequent increased potential of exposure to nanomaterials in the working environment. However to determine the potential exposure risk is a challenging task for risk assessors, due to limited availability of data on nanomaterial exposure level. To face this challenge a number of methods have been developed including the “Control Banding Nanotool”, the “Swiss precautionary matrix”; “Stoffenmanager Nano version 1.0; “ANSES - Development of a specific Control Banding Tool for Nanomaterials”; “NanoSafer vs. 1.1 – A web-based precautionary risk assessment tool for manufactured nanomaterials using first order modeling”
Based on the literature information we have analyzed these tools and discussed elements regarding: the domain of application and whether it accounts for the nanospecific factor or nano-relevance; the work exposure scenario, for which types of processes they may be used; are the tools using the source-transmission-receptor approach; the input data requirements; whether the tools included qualitative or semi-quantitative or quantitative evaluations of the exposure; whether the final output is qualitative or semi-quantitative or quantitative.
We observed that the tools were developed based on different needs, but that the domain of application is not always well defined. Moreover, derived exposure potentials or exposure levels are usually based on assumptions or expert opinions, and some concepts were purely theoretical. Therefore, immediate combination of the different models into a larger holistic framework is not possible. Further development of the frameworks, harmonization and validation is needed in future research.