fallhell buddy, I'm so happy to see you I won't even take my customary shot.
Go to the hardware store. Get one of those rectangle air vent filters for air conditioners (my apartment has this type, I replace it once a month). The brand name is "Flanders". Take a stout pair of scissors and cut out what you need to cover whatever vents you want on your monitor and computer. Find a decent tape to attach your filter piece to the vent. If appearances matter, make sure the tape color fits the color of what you are taping it too. The filter should catch any dust, smoke, whatever.
And that should do it. :hatsoff: