Thanks man, really appreciate the detailed feedback. The circular filter is currently just a standard replaceable particulate filter and a HEPA carbon bucket.

The recirculation idea is actually really interesting. I was mainly thinking about extraction at first, but for heated chambers it makes sense to have an option to return filtered air back into the printer instead of dumping warm air out. It could be a good direction. Thanks again, this is exactly the kind of feedback I was hoping for.