The question if pigmentary Titanium Dioxide is a “nanomaterial” depends solely on the legal definition of the term “nanomaterial”. While the ISO TS 27687 (2008) defines the term “nano-object” (at least one dimension < 100 nm) and ISO TS 80004-1 (2010) the term nanomaterial (external [nano-object] and internal structure [nanostructured material]). Recommendations from the EU commission*1) and International Council of Chemical Associations (ICCA) are presently competing proposals for final approval.
As virtually all particulate materials through their low end of the particle distribution curve contain particles which meet the definition of a “nano-object”, the main difference in the definitions are the cut-off criteria. The present political discussion focuses mainly on the definition of a cut-off using weight concentration (10 % ICCA)
or number concentration (1 % EU Commission, which means less than 0,01 % by mass concentration for pigmentary Titanium Dioxide).
Agglomerates and aggregates formed by nano-objects resulting in particle diameters > 100 nm, so called ”nanostructured material” are included in both definition as well. How the criteria of the internal structure will play a role in the legislation is still under discussion.
As a summary it can be concluded from the available data that generally pigmentary Titanium Dioxide will fall under the “nanomaterials” if authorities decide to use the EU draft definition and not fall under this term if the ICCA definition will be selected as the basis for legislation.