In reply to @susandavidsonm2

@SusanDavidsonM2 @sameo416 @Ikat0 @TulaGbefi @JimRosenthal4 Here's some data on filters getting "full" over time. Filtration efficiency goes up. However, with filters that have an electrostatic charge (many HEPA and MERV filters these days), the data is a little more mixed.