Years ago, I lived in a completely tiled, fairly new apartment with a central air handler. Being sensitive to all kinds of stuff, I changed the air filter regularly, I was amazed at all stuff in the filter. While on a visit in the attic, I noticed I could see light where the air duct joined the ceiling. Soon there after, I sealed the gaps by using silver duct repair tape from the inside of the ducts to the drywall and reinstalled the duct covers. That act alone seemed to reduce the amount of stuff in my air filter work by 80%. I suspect the act of air coming out of the ducts would also suck drywall dust and attic insulation dust into the room. So if you do the duct cleaning thing, check the gaps first, and seal as necessary to reduce dust.