Manufactured nanomaterials are produced intentionally of practically any of the chemical elements in the periodic system.
Natural nanomaterials, are often called ultrafine particles or nanoparticles and can form anywhere in the environment. Examples are gas-chemical reactions in the atmosphere, rust in the soil, and minerals in evaporating water.
Incidental nanomaterials are by products from processes. Examples are smoke from candle lights, exhaust emission particles from diesel engines, welding, and high-energy grinding.
Source: H2020 caLIBRAte