On June 10, 2022, the European Commission (EC) announced that it is clarifying the definition of nanomaterials in a new Recommendation that supports a coherent European Union (EU) regulatory framework for nanomaterials, helping to align legislation across all sectors. The EC states that the new definition should be used in EU and national legislation, policy, and research programs. The Recommendation states:

‘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:

1. one or more external dimensions of the particle are in the size range 1 nm to 100 nm;

2. 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;

3. 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.

4. 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 2/cm³ shall not be considered a nanomaterial.

The new definition replaces the definition published in 2011. According to the EC, it developed the revisions following a comprehensive review, and the revisions “should allow easier and more efficient implementation, but will not significantly affect the scope of identified nanomaterials.”