I am sure that Russ Andrews will have something that uses reverse engineered Klingon technology costing several thousand pounds that does this (allegedly).
I guess the only real way to do it is to have some sort of air filtration system either in the room where the equipment is or the whole house. Not cheap. I say something like this on Grand Designs the other week becasue the kids were highly allergic to everything, so air purification was important.
Unless you are looking to use your AV whilst wearing a space suit or want to hermetically seal the rooms with hepa filters then simply use a few drops of fabric conditioner in water and use a very well wrung out cloth. The fabric conditioner has anti static ingredients for clothes, it should help avoid the static charge attracting dust to your equipment. you can't eliminate the problem but it will reduce it.