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July 10, 2023

Switzerland Updates Precautionary Matrix for Synthetic Nanomaterials

Lynn L. Bergeson Carla N. Hutton

Switzerland’s Federal Office of Public Health (FOPH) has updated its precautionary matrix for synthetic nanomaterials, which is a method for assessing the nano-specific health and environmental risks of nanoproducts. According to FOPH, the precautionary matrix enables the structured assessment of the “nano-specific need for precautions” when handling synthetic nanomaterials. The precautionary matrix is designed “to help industry and trade comply with their due diligence and their duty to exercise self-control opposite employees, consumers and the environment.” According to the information on versions of the precautionary matrix, the revisions include:


  • The European Commission’s (EC) June 10, 2022, Recommendation on the definition of nanomaterial (2022/C 229/01) has been implemented.

Exposure Potential

  • To estimate the emission rate, the user can select specific exposure scenarios based on matrixes (such as plastics or textiles). For the inhalation exposure path, the room size and air exchange rate are now also queried, whereby predefined scenarios can also be chosen (such as household and workplace);
  • Measured or modeled exposure values can be included in the precautionary matrix;
  • The maximal workplace concentration value for diesel soot is no longer used to estimate the exposure potential. The new reference values derived from toxicity studies for different nanomaterial categories and uptake pathways; and
  • The additional assessment parameter dustiness or a manually entered emission value can be used to estimate the exposure potential.


  • At certain parameter entries, the user is asked for the related uncertainty to provide the final result with supplemented “uncertainty” information. The “uncertainty” percentage specifies the probability of the actual score exceeding the threshold, indicating the need for precautionary measures.