What particlegenarator should I look at? I tried Trapcodes particular, but it's forces is in the "smoke" area.
I would like to make a heavy type of dust, as if coming down from a cieling during an earthquake.
I also need to make very light dust as if blow away from an old dusty table or shelf.
There are a number of emitters in the pI3 libraries that can be turned into falling dust, specifically some of the snow/blizzard ones. It's all really a matter of changing the colour and the Weight so that the particles fall faster.
Same goes for table dust. You'd likely need to adjust the Velocity over Life or Weight over Life so that after the particles get blown up into the air, they linger momentarily before starting to fall again.