A tad bit of info here , you will never get a paint job that doesnt get any dirt in it , I paint in a 75K down draft every day , and what most people dont understand is most dirt comes from you, air hose , paint gun, you drop the hose on the floor to reload your paint gun ? then pick it off the floor and keep shooting ? the first 5 feet of my hose never hits the floor as I hand it around my gun hanre when I have to reload.

There will always be small particles in the air no matter what , it will even get through our high dollar filters . Another thing is , if yor painting in your garage and your air compressor is in the same room as you when it kicks on and the belt turns , theres air movement and vibrations will rattle dust from everywhere.

Try using a 3M tac cloth , its a white scuff pad with bees wax on it , and I have had excellent luck with them .

SprayTech