Thanx for the concern. I,and my many buds ,don't use those filters BUT after my reserve tank I have a oil filter to catch any water that condenses in the reserve tank,When your dredging 40+ hours a week as i do you get at least a quart of water outta your reserve!! Much more worried about water than air quality.Once it's pressureized in the reserve anything in it drops out except some water.I clean my reserve with 25% bleach every month during dredge season to prevent mold also,just put in a cup and shake for a couple a minutes.It does take several rinsing and a drop a soap to freshen but taking care of your lungs is pretty dang important!!Hope you guys kick some butt this year!!I'm living vicariously thru my many friends adventures this year but at least I stand a 72% chance of seeing XMAS-Tons a au 2 u all-John