I'm again on a mission to reduce the amount of dust flying around the house upstairs. It's not a problem downstairs.
The house I grew up in was one story ranch style. Before I started 1st grade, my father converted our furnace from coal to heating oil and installed hot water baseboard circulating heat. We didn't have AC. There were no blowers. We had those wide aluminum Venetian blinds. They say they didn't generate static electricity, which attracts dust like plastic miniblinds. Of course, my mother would have kept up with dusting, but I don't remember ever seeing her doing it, and it certainly wasn't one of my jobs. I don't remember seeing dust (or giant cockroaches) until I moved south.
When my parents moved here in the mobile home, they bought a large air purifier that sat on the floor. My mother swore it helped with dust, so she must have discovered more dust after leaving Ohio also. The filters are no longer available, and it was very noisy, so I tossed it. New ones cost at least $100 and they say you need one in every room. [Really???]
There are two separate HVAC units in this house---upstairs and downstairs. Here's what I have learned.
In a 2-story house, even if you have two HVAC units, an open stairway can act like a wind tunnel pulling dust up from the first floor, because heat rises. Braided rugs can act like little puffers, puffing out dust every time you step on them, but still better than wall-to-wall carpet. Curtains trap dust worse than miniblinds. Dust builds up under a bed, not just because you dust under there less often, but because there is less moving air under a bed. Once dust in the air gets under there it doesn't move on. A bed likely acts like a puffer also, especially if you jump on it (which I don't).
I did an experiment by taping a regular 20" x 20" air filter to the input side of a cheap box fan. It's been going 24/7 for about a month in the bedroom. There is clearly dust building up on the filter now, but it took a long time. This fan is so quiet on low speed I can barely hear it. I'm going to build one of those boxes with 4 filters and the fan, put it in the hallway upstairs, and see if it catches dust trying to sneak up the stairs.
The next project is to change or improve as many of these things as possible.