Hey welcome back. I know nothing about dust and went looking on line for more information, not the adds but the science: good luck.
Just some of the things that comes to mind are questions;
Does warm air hold more dust than cool air? My walls are dirtyest just above basebard heaters.
Does air pick up dust, or just move it around when raised by others?
Where does dust come from? Outside, Main enterence and traffic path. People and pets, in the center of living space?
Does warm or cold air transport more dust and what effect does moisture have to do with it?
Where are the return vents compared to where the dust is, perhaps it drops all the dust before it gets there?
And then I did find one suggestion that the wife might not want to here, it's called top down cleaning and might be worth trying.