Thanks for the write up Nathan, some good information and the meters show the results. Sounds like that may be my ticket for a air cleaner. I have been thinking about using a box fan or two with the filters attached. When I built the shop I installed a few switched outlets in the ceiling just for that purpose.
I was thinking more in the lines of a stackĀ of filters, so one could replace one and rotate the others out. At least that was the thought.