As　infectious　respiratory　diseases　are　highly　transmissible　through　the　air,　researchers　have　improved　traditional　total　volume　air　distribution　systems　to　reduce　infection　risk.　Multi-vent　module-based　adaptive　ventilation　(MAV)　is　a　novel　ventilation　type　that　facilitates　the　switching　of　inlets　and　outlets　to　suit　different　indoor　scenarios　without　changing　ductwork　layout.　However,　little　research　has　evaluated　MAV　module　sizing　and　air　velocity　selection,　both　related　to　MAV　system　efficiency　in　removing　contaminants　and　the　corresponding　level　of　protection　for　occupants　in　the　ventilated　room.　Therefore,　the　module-source　offset　ratio　(MSOR)　is　proposed,　based　on　the　MAV　module　size　and　its　distance　from　an　infected　occupant,　to　inform　selection　of　optimal　MAV　module　parameters.　Computational　fluid　dynamics　simulations　illustrated　contaminant　distribution　in　a　two-person　MAV　equipped　office.　Discrete　phase　particles　modelled　respiratory　contaminants　from　the　infected　occupant,　and　contaminant　concentration　distributions　were　compared　under　four　MAV　air　distribution　layouts,　three　air　velocities,　and　three　module　sizes　considered　using　the　MSOR.　Results　indicate　that　lower　air　velocities　favour　rising　contaminant　levels,　provided　the　ventilation　rate　is　met.　Optimal　contaminant　discharge　can　be　achieved　when　the　line　of　outlets　is　located　directly　above　the　infected　occupant.　Using　this　parameter　to　guide　MAV　system　design,　85.7%　of　contaminants　may　be　rendered　harmless　to　the　human　body　within　120　s　using　the　default　air　vent　layout.　A　more　appropriate　supply　air　velocity　and　air　vent　layout　increases　this　value　to　91.4%.　These　results　are　expected　to　inform　the　deployment　of　MAV　systems　to　reduce　airborne　infection　risk.