**Abstract**

Nanoparticles, also known as ultrafine particles, present in polluted air have shown a detrimental effect on human health, especially on respiratory and cardiovascular functions. They are considered nanopollutants and, given their small size and unique physicochemical properties, it has been suggested that they could reach the brain through the olfactory nerve pathway. Neurodegeneration is on the rise, especially in highly polluted cities, and a variety of nanoparticles present in the air have been related. Recent findings on airborne nanoparticles translocation routes and neurodegenerative processes may allow us to better understand the impact of nanopollutants in human health. The outcomes may have major implications in the development of public policies and regulations required to protect human health from exposition to nanomaterials, produced either incidentally or by design.

**Keywords:** nanopollutants, nose-brain translocation, neurodegeneration, inhaled, ultrafine particles
