system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: What does the "ion" button on fans do?

I mean, I was told that it ionizes the air (whatever that means?), but does it actually have any benefits of turning it on?
gpt
The benefit is that ions help to remove dust from the air.

The air purifier releases negatively-charged ions into the air.  Dust is positively charged, so the dust and ions attract each other.  This operates on the same principle that makes CRT screens attract dust -- the screen has a negative charge from electrons hitting it.

Once enough ions attach to a dust particle, the whole thing becomes heavy enough to fall to a table or other surface.  Then you wipe the dust off the surface.