The OP's shorthand for Air Filtration System, also known as an ambient air cleaner.
A TIP for you when you choose a final location... If there is a location(s) where you typically generate a lot of fine dust (such as sanding) try to place the air cleaner so that its air intake is located in front of you (i.e. you should be facing the intake). Setup this way the air cleaner will be drawing fine dust *away* from you, not blowing it back at you.
Otherwise, there is nothing wrong with locating it towards the center of your shop. You just want to avoid major obstructions to the air flow. The idea is to create a 'river of air' flowing from its exhaust to the back wall, around the perimeter walls and then drawn back in through the front air intake -- a continuous 'river of air'.
There are some locations that will be more optimal than others, and often times that comes from trial and error if you are truly determined. However, so long as there is a good circulation pattern the air cleaner will do its job and draw in the dirty air and spit it back out as clean air. You should find that there is considerably less fine dust settling throughout your shop after heavy sanding sessions after installing your new air cleaner.
After sessions of dust generation, be sure to let the air cleaner run for an additional hour or two to finish scrubbing the air. If your air cleaner did not come with a timer, it is worth adding an aftermarket timer for just this purpose.
