I dont think it filters anything - it just provides the dust a place to lay down until something knocks it up into the air. It would have to have some mechanism for getting the dust to the other side to act as a filter, and then you'd still have to clean/dispose of it somehow.

More of a grinder to make sure anything big enough to fall out gets smashed up into particles small enough to stay floating. (Less the occasional cleaning, which... isn't comprehensive. wash a used rug someday. ick.)

Carpets really just molt and let its shit go into the air.