In 2011, the European Commission published a first common definition of the term “nanomaterial” (2011/696/EU). This was updated in 2022:
‘Nanomaterial’ means a natural, incidental or manufactured material consisting of solid particles that are present, either on their own or as identifiable constituent particles in aggregates or agglomerates, and where 50% or more of these particles in the number-based size distribution fulfil at least one of the following conditions:
- one or more external dimensions of the particle are in the size range 1 nm to 100 nm;
- the particle has an elongated shape, such as a rod, fibre or tube, where two external dimensions are smaller than 1 nm and the other dimension is larger than 100 nm;
- the particle has a plate-like shape, where one external dimension is smaller than 1 nm and the other dimensions are larger than 100 nm.
- In the determination of the particle number-based size distribution, particles with at least two orthogonal external dimensions larger than 100 μm need not be considered.
However, a material with a specific surface area by volume of < 6 m2/cm3 shall not be considered a nanomaterial.