I think it's more like 99% on particularly bad days, because where I live over 100 ug/m3 is common during the fire season (which is apparently now November to A

I think it's more like 99% on particularly bad days, because where I live over 100 ug/m3 is common during the fire season (which is apparently now November to April) But if you live in places where the particulates are normally low then yeah, cutting from 50 to 5 is hard.