1. Advantages of Wall Mounted Air Quality Control Systems
Units placed closer to the source of the contaminant:
purifies air faster, can significantly reduce dissemination of contaminant
pulls contaminants away from occupants, not into breathing zone
More likely to create whole-room circulation and have greater area of clean-air distribution due to fewer obstructions as air flows across ceiling
Exhausted air isn’t blowing directly on room occupants
Less intrusive, more integrated placement deters tampering
Floor-stand units can be an obstacle, take up floor space, and become hazardous in areas where floors can become wet (restrooms, locker rooms, cooking areas, etc.)

2. Computational fluid dynamics demonstrates how – in this restroom scenario - mounting an air quality control system high on the wall, over the source, significantly reduces the contaminant from spreading into the room.
Contaminant is more contained when unit is over source.
Contaminant can spread further into room when unit is low, not over source.