but having no fresh air exchange That 'but' isn't a given, modern houses which are properly sealed should have ventilation as well specifically to address that

but having no fresh air exchange That 'but' isn't a given, modern houses which are properly sealed should have ventilation as well specifically to address that issue. Proper ventilation comes with inlet filters but those usually don't keep out PM<x> so still the purifier will have to do sme more work because of the constant sucking in of polluted air. However, I honestly do not know how common venitlation is already on other continents than mine where it's been made pretty clear by now that sealing a house equals need for ventilation.