https://www.atsjournals.org/doi/full/10.1164/rccm.200202-138...
https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1365-2362....
https://www.researchgate.net/publication/343237144_Role_of_N...
...
When you try doing it, you start noticing a strong smell that smells like early spring or the smell certain air purifiers make. This smell lasts as long as you keep humming.
https://www.atsjournals.org/doi/full/10.1164/rccm.200202-138...
https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1365-2362....
https://www.researchgate.net/publication/343237144_Role_of_N...
https://www.atsjournals.org/doi/full/10.1164/rccm.200202-138...
...
When you try doing it, you start noticing a strong smell that smells like early spring or the smell certain air purifiers make. This smell lasts as long as you keep humming.