It's not bad, but I sure would alter the drawing of the recirculating ventilation system unless I want to point out why they don't work well.  That's the little split drawing with the diffuser and return over head on the left, and the floor level diffuser on the right with the return right above it.  Those positions show the weak points of that kind of ventilation since they short circuit the pathway for the air.  We have use diffusers like that second one in the buildings I do including the one that won the AIA COTE award in 2016.

MY QUESTION FOR YOU:  is the saline aerosol test what is used for generation of a 0.3 micron test particle?  Attached find an N95 pressure cooker article.  I don't need anything but the info that is NOT present here which is whether or not the efficiency measured is at 0.3 microns.  Because that's the size of much of the virus aerosol.

Monona