Nanoscale materials are of significant scientific interest because some material properties can change at this scale. Such changes are challenging our understanding of hazards and our ability to anticipate, recognise, evaluate and control potential health and safety risks.

Nanoparticulate forms of some materials show unusually high reactivity, especially for fire, explosion and in catalytic reactions.

The term nanotechnology generally refers to engineered structures, materials and systems that operate at a scale of 100 nanometres or less. Nanoparticles can occur naturally (viruses and bushfire smoke), incidentally (diesel and combustion exhausts), and through engineering processes (carbon nanotubes).