MUA systems normally pressurize corridors. The idea is to force fresh air into the units via the gaps around the doors, while the unit’s interior air is exfiltrated out windows, exterior doors and in-unit ventilation fans.
So, it depends on where the smell is coming from. is it coming in from the corridor, in from an exterior window/door or is it escaping an adjacent unit through the unsealed floor/wall connection or electrical devices in the wall.
Originally Posted by Brian S