However, nanoparticles can also be anthropic, which means that they are generated by human activity. The vast majority of anthropic nanoparticles are unintentional byproducts of phenomena like combustion, friction, or of manufacturing processes.

These nanoparticles are often referred to as the ultrafine particulate matter present in air pollution. It is only recently that scientists have begun to deepen their understanding of the health impacts of this kind of pollution.

Engineered nanoparticles are intentionally made by man. Engineering nanoparticles is one of the applications of nanotechnology. The resulting materials are intentionally nanostructured to give them special and often innovative properties. A "full-size" material's mechanical, chemical, magnetic, electrical, and other properties change when the material manufactured at the nanometric (one millionth of a millimeter) scale. It is these modified properties that have made nanomaterials a source of hope for solving some of our planet's major challenges, from saving resources and energy to curbing pollution and preventing infectious diseases.

Some economists even believe that nanotechnology will drive the emergence of a whole new industry in the 21st century—one that could disrupt today's automotive, microelectronics, and other industries.

However, engineered nanoparticles do raise some legitimate safety questions. Are nanoparticles safe to use in everyday items? What is their impact on the environment?

For nanomaterials to add value to the economy, products made with these materials must be "safe." And both workers and consumers must be fully informed about what nanoparticles are present, how they should be used, and what should be done with them at the end of the product's lifecycle. This requires clear answers to safety questions at each stage of the product lifecycle.