I also worked on a very large extremely quiet air filtration appliance, using an extremely quiet quite big fan (500 mm blade diameter, 540 mm square frame) I have designed, and continue to improve.  This is the google folder for cad files etc, related things such as the SDP810-125A based micromanometer code are also here:

https://github.com/adouglas89/Big-quiet-air-purifier and https://sites.google.com/view/bqap/home

www.bigquietfan.com  <--- This is the big one for now, which I spend most of my time on.

UVC Nukit torch mod for external power/constant operation:

https://docs.google.com/document/d/1BQh_6jLaWd9nHVWsMZghqf-FgCTMaG_XzB_kwg550y4/edit?tab=t.0

The under chin personal hepa is also now nearly complete, I just want to reinforce some areas of plastic to make them a little stronger:

https://github.com/adouglas89/Personal-Under-chin-HEPA-purifier