One illustrative system disclosed herein includes an upper filter, a lower filter positioned vertically below the upper filter, at least one incoming air inlet positioned vertically above the upper filter, and a vacuum pump positioned vertically below the lower filter, the vacuum pump including an outlet, wherein an incoming air stream is adapted to flow downwardly through the at least one incoming air inlet, then through the upper filter, then through the lower filter and then out of the outlet of the vacuum pump where it exits as a cleaned air stream.