We applied a novel ventilation concept to improve air cleanliness and recovery times in critical healthcare spaces such as theatres and laboratories. Using computational fluid dynamics, we compared baseline HVAC layouts with enhanced ultra clean ventilation arrangements, representing supply diffusers, extraction strategy, thermal plumes and equipment and occupant heat loads. The analysis reported particle removal efficiency, recovery after disturbance, flow uniformity across the sterile field and draught risk for occupants. The model used realistic boundary conditions and representative operating scenarios, with mesh and solver settings chosen to resolve near‑field jets and entrainment. Sensitivity checks ensured robust comparative conclusions. The concept improved flow stability across the critical zone while avoiding undesirable recirculation that can re‑entrain particles. The results translate directly into HVAC design guidance for diffuser selection and placement, canopy geometry and control set points, supporting compliance aims and practical implementation by Medical Air Technologies.