Thanks to all who offered advice. I guess there's no way around exhausting outside and bringing in makeup air. My tentative plan is to get a harbor freight dust collector to suck air out of my finishing area to the outside and open a window in the other end of the basement to bring in fresh air. I don't have a window in my finishing room so I need to move air through ducts to the outside. I'll post back when I have things set up.Thanks again.