Comparative Effectiveness of Negative Pressure, N95 Respirators, and HEPA Evacuators in Reducing Aerosol Exposure During Inhalation Therapy: A High‐Fidelity Simulation Study

Background Inhalation therapy, widely used for asthma and COPD, remains classified as a potential aerosol‐generating procedure (AGP), leading to restrictive infection‐control practices. Evidence on aerosol dispersion and the comparative efficacy of mitigation strategies—including negative pressure (NP), HEPA evacuators, and mask type—remains inconsistent. Research Question Which mitigation strategy most effectively reduces healthcare worker aerosol exposure during inhalation therapy: NP rooms, N95 respirators, surgical masks, or portable HEPA evacuators? Study Design and Methods A high‐fidelity simulation quantified aerosol dispersion during inhalation therapy in an isolation suite. Two delivery methods (T‐tube and mask inhalation) were tested under two breathing conditions (minute ventilation = 12 and 30 L/min). Each was evaluated with or without an NP, HEPA evacuator, and three PPE states (N95 respirator, surgical mask, or none). Aerosol concentrations were continuously measured for 10 min at three standardized near‐field sites located 50 cm from the mannequin′s mouth. Results NP achieved the greatest and most consistent reduction, lowering aerosol levels by 75%–78% across all conditions. N95 respirators reduced exposure by 35%–50% relative to surgical masks, which in some low‐flow settings exceeded no‐mask baselines, indicating leakage. HEPA evacuators showed conditional efficacy—reducing aerosols by 27%–45% during mask inhalation but paradoxically increasing concentrations by up to 29% during open‐circuit T‐tube use due to suction‐induced recirculation. Pooled analysis identified NP and N95 respirator use as the dominant factors associated with exposure reduction ( p < 0.001). Interpretation Aerosol dispersion during inhalation therapy depends on ventilation rate and device type. NP combined with N95 respirator use provided the most effective protection (> 80% reduction). HEPA evacuators were beneficial in partially sealed mask systems but counterproductive in open‐circuit T‐tube setups, supporting prioritization of NP environments and N95 respirator use over surgical masks or single‐point suction systems.