Being inside of a dust cloud will damage everything (almost everything?) on your ship, including engines, hull, guns. Possibly damages balloon, but I am not 100% sure. This happens regardless of whether you are moving or not. This means you generally want to be moving as long as you are moving against the cloud, not with it. Moving with the cloud keeps you in it longer.
Regular clouds on dunes are a nice white. Dust clouds are a brownish color, much closer to the color of sand.