My DeWalt 788's blower (Type 1) does an excellent job at keeping dust off my lines.
It was one of the very first things I noticed about the 788, how much better it was at keeping the dust off my patterns, even when scrolling at slow speeds.
It's one of those "little things" that has greatly reduced my frustration while scrolling.
I use a large box fan with a furnace filter to trap the airborne dust that is generated by my scroll saw, and I also have a HEPA filter running 24 hours a day that should clean up any dust that remains (I use the scroll saw in my home, so that is the reason for the multilayered dust collection).
I also wear a 3M 6000 series respirator at all times while I am scrolling, cutting or sanding wood. I won't do any work without it.