This cannot be overstressed. Most refiners have a good hood and scrubber and overlook their waste buckets. If you have open waste containers where spent acids sit, you need to keep the hood on or store them in closed containers.
As far as scrubbing is concerned it depends on what you are refining. If you are collecting foils from circuits using AP, the hood is just to clear the work space and the fumes are not so bad. Unless your garage is close to someones house or their garage. But usually 10-20’ and an upward exhaust will suffice with AP.
But when you collect enough foils, that reaction needs a scrubber to eliminate the NOx if working with volume.
And all spent chemicals need to be covered sufficiently.
So I guess the next question is what are you planning to refine and how?
