The European commission tries to define nanomaterials.

In 2010, the European Commission held a short consultation on a proposed definition for nanomaterials, to be used in European Union legislation and programmes. This was in response to a European Parliament resolution, and the definition followed a proposal by one of the Commission's scientific committees. The definition has three parts: on size distribution, size of internal structural elements, and surface area; a material caught by any of these parts meets the definition. There are a number of problems. The definition seems to be written with engineered nanomaterials in mind but as written applies to non-supplied materials, such as smokes. The structural element component seems to capture items such as sunscreen and tennis rackets, which include nanomaterials. Use of the definition will require some international standards, which have yet to be written and which will involve some difficult decisions. It is understandable why there are both size and surface area requirements, but they are not wholly consistent. The Commission plans a further consultation in 2012, but it might be better to delay this until after the standardisation work.