In many big cities, getting a lot of dust is nearly out of your control, the only factor you can control is how often you gather it all up. I used to live practically next to a four-lane road when I was younger and even if you kept the windows closed, the dust would still creep in with every coming and going. If you ever opened a window, you'd know you'd need to vacuum soon.
Agree on dust removal. But if you have a constant source of pollutant input such as air pollution, dust or pollen, you want to be running a filter 24/7.
Large buildings don't run their HVACs in burst and then turn them off.
- Running an Air Filter 24/7 has huge diminishing returns (i.e. waste of electricity). They are best run at max fan speed for short durations instead.
- Elevate it with a platform.
- Get a vacuum (or even a robo vacuum). I grew up in a 100+ year old house, it wasn't dusty, and had hard-woods/brick everywhere.