Which Purifiers or centralized purifier for 3/4 story house

Hi All,

I have 4 floors. Bottom is partially below ground, which has a 2 car garage and wine cellar. The main or 1st floor has two rooms 85m2 (~950 square feet) living room w/ kitchen (open space) and a seperate 100m2 (~1050 f2) pool (covered when not in use). There is another floor also ~950 square feet that is made of stairway, bedroom, walk in closet 15m2 (150 f2) and bathroom 25m2 270 f2. I normally don't use the bathroom that often but the dog sleeps there b/c it has tiles and so it gets dusty. Top floor has similar layout (2 bedrooms, bathroom, and hallway).

All in all I'm wondering if it's worth while to add to air recuperation unit w/ a HEPA or some filter or invest into air purifiers. The problem is that the house is super dusty all the time, may do to the dog or that we are ~50 feet from the forest? Any recommendations?