I am not trying to be funny, but why not use something that will actually stop dust. Instead of an outdoor screen, why not use something like pantyhose. Seriously, it allows air flow but will trap dust better. I used my wife's pantyhose as a second layer when I had to re-insulate our attic. That being said, if you use something that is actually efficient, you will have to be diligent about cleaning them or it may lead to overheating and a voided warranty.
