The design is mostly straight forward.  It will be a TPU based filament that holds the ULPA filter compressed in place.  The fan will optionally be centrifugal (default) or axial.  Additional prefilters will be optional.

https://www.thingiverse.com/thing:3454725 is the original design in Fusion 360.  Several models will be redesigned for fit and new performance in OpenSCAD.

Based on the M12 lithion battery pack and USB-C powerbank.