Honeywell - HPA060

I've had a Honeywell HPA060 in the room with the liter box since 2013. It's still going! I also have the larger version HPA 160 in each bedroom to help with allergies. When the wildfire smoke summer came to the region, our indoor air quality was still fine while it turned yellow outside. It basically only has 3 fan speeds, a true HEPA filter and a carbon filter. Option to buy carbon prefilter with added zeolite for more odor absorption. I should mention that as a former pet sitter, getting an air purifier to handle litter box odor rarely works. The amount of odor causing material that renews the smell basically overpowers any air purifier's capacity to absorb it, especially with ammonia. What's happening is that even after you clean it, little particles break off and build up in the box over time. They continue to give off odors even if there are not clumps in the box. So, the best way to keep the smell down on top of scooping is to completely change and wash the litter box about once a week and have the box in a well ventilated room. The smell can also be more pronounced in small spaces where the air doesn't change over much, like in a laundry room or closed bathroom. Putting an air purifier in a room like that basically just recycles the stinky air in the room because it's already absorbed as much as it can. Air purifiers do, however, keep down litter dust, which can carry the odor through your house. Clay litters make a lot of dust, but are better at trapping odors. Silica crystal litters tend to stay put as far as dust goes, but they don't do much for the smell. Corn, newspaper, and walnut type litters are the worst for smell and should be completely changed every 2-3 days. No litter or air purifier can cover up the smell from an uncovered poop. Some cats just won't bury their doodies. I use Feline Pine. I was skeptical at first, but the rescues near me use it, which convinced me. It smells like a fresh forest when you first put it down. It's easy enough to scoop. It does make some dust when you pour it out fresh, but when the cats are in the box it doesn't make a lot of dust or track through the house on their paws. It's also very absorbent and neutralizes pee smells. Just like any other litter, it'll need to be completely changed every now and then. One last trick of the trade -- get a blacklight flashlight. Shine it on the walls and floor around the litter box to see if any pee particles sprinkled when they tinkled.

So the winix has the ionizer which produces ozone, a lung irritant. I actually bought this model and ended up returning it because of this. Also it’s enormous. I know the levoit is a popular brand but haven’t personally used it.  I’ve had my Honeywell HPA060  going on 6 years now and have been happy with it, though I wouldn’t replace it if it broke, because my r/crboxes do a much better job and it costs less to replace the filters. 

You can get a HEPA filter air purifier (Honeywell makes decent ones) to deal with PLA and TPU, they dont emit the toxic VOCs like ABS, Nylon and PC, but they do still emit fine particles. Having it enclosed like you do is going to prevent a lot of those fine particles from scattering through the room though so its a big help. As a rule I try to not have my printers in the same room I work, but if you must, that HEPA filter will help reduce the fine particles a lot. For the more toxic materials, absolute best bet is to create a negative air pressure environment while venting outside through a window or port. If you cant or want even more reassurance, running a carbon filter does a lot to help. There are specialized air purifiers for VOCs but theyre not cheap. A really good one you can get is from Heygears, called the GreenPrint Purification Unit. Just know it's specifically for VOCs as it doesn't trap particles, it destroys them (so you still want a HEPA for the fine particles). This air purifier doesnt need filters though, it doesnt trap VOCs like a carbon filter which can become saturated and need replacements. It actively breaks down VOCs, so it just runs indefinitely with full efficiency, no need to swap filters.

We have a Honeywell with a hepa filter. It has been great, though a tad expensive.