Decided to change all 3 filters in my air cleaner in the cat litter box room since I was starting to smell pee despite cleaning the litter box. I guess that's how I know the filter system really works, when the filters start to be depleted I can actually tell.
Filters were super dirty. I think from now on when cleaning this I will bring the whole unit outside, that was a mess lol. I try to stretch them for 6 months, but given the proximity to litter box I should probably be doing at least the dust filter once a month.
There's also some improvements I could do to this unit, like better filter slides. Right now the filter ends up rubbing against the top portion when taking it out, which makes the mess worse.