Essentially all air filters filter nano particles.

https://smartairfilters.com/en/blog/can-hepa-filters-capture...

That's specific to HEPA filters. Most air filters are not as capable as HEPA filters.

Read the rest of the article. The cheap furnace filter filters nanoparticles too, just not as well. Both larger and smaller particles are pretty easy to filter. It's the ones around 0.3um that are the toughest to filter.

That's brutal! We're poisoning ourselves.