To be or not to be a nanomaterial
Journal article, 2022

In early 2021, the new definition of the term “nanomaterial” proposed by the European Commission (EC) was subject to a stakeholder consultation and in June 2022, the EC published its updated definition. Based on an independent analysis of the different versions of the definition and the results of the stakeholder consultation, the aim of this paper is to identify key aspects to be considered when deciding whether a material should be regarded as a nanomaterial. More than 130 comments submitted during the stakeholder consultation by various organizations, companies, citizens, and authorities were analyzed. We find that the introduction of new terms such as “solid particles” has added clarity to terms used in the former definition. Our analysis shows that stakeholders seemed inclined to maintain the default number-based 50% threshold value, but were opposed to (1) the possible flexibility of varying the threshold in specific sectorial legislation, (2) the default inclusion of carbonaceous materials < 1 nm, and (3) the use of volume specific surface area (VSSA) other than for excluding materials from being defined as nanomaterials. Overall, we find that the updated definition addresses many of the limitations of the former definition. However, the updated definition also creates new challenges that will have to be addressed via development of new regulatory guidance. Apart from the relatively minor change of the VSSA threshold from 5 to 6 m2/cm3, it generally seems that no arguments from the stakeholder consultation made the EC reconsider its position. Graphical Abstract: [Figure not available: see fulltext.].

Volume-specific surface area


Particle size distribution

European Commission



Stakeholder consultation


Steffen Foss Hansen

Technical University of Denmark (DTU)

Maria Bille Nielsen

Technical University of Denmark (DTU)

Oliver Foss Hessner Hansen

Technical University of Denmark (DTU)

Lauge Peter Westergaard Clausen

Technical University of Denmark (DTU)

Lars Michael Skjolding

Technical University of Denmark (DTU)

A. Baun

Technical University of Denmark (DTU)

Rickard Arvidsson

Chalmers, Technology Management and Economics, Environmental Systems Analysis

Journal of Nanoparticle Research

1388-0764 (ISSN) 1572-896X (eISSN)

Vol. 24 12 235

Subject Categories

Production Engineering, Human Work Science and Ergonomics

Social Sciences Interdisciplinary

Environmental Management



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