Air disinfection effect of different disinfection methods in high‐risk healthcare spaces

To evaluate the field performance of human-occupied air disinfection strategies in high-risk healthcare areas, field tests were conducted in the high-risk triage area, infectious disease ward, and dental clinics of a top-tier academic medical center. Existing air disinfection or ventilation-based control measures, including plasma air disinfection devices, ultraviolet (UV) air cleaners, and negative-pressure ventilation systems, were evaluated alone or in combination with a 222-nm UV upper-room air disinfection system. No air disinfection intervention was used in the control group. Air sampling was performed hourly during daytime clinical hours using a six-stage impactor microbial sampling method or a settle plate method. Compared with no-disinfection controls or existing-measure comparators, airborne bacterial concentrations were generally lower in the 222-nm UV group or 222-nm UV add-on groups across multiple clinical settings. Percentage reductions relative to valid comparators ranged from 48.04% to 73.74% for 222-nm UV alone and from 6.86% to 73.77% for 222-nm UV used as an add-on to existing measures. These findings suggest that 222-nm UV upper-room air disinfection may reduce airborne bacterial concentrations and improve air hygiene quality under routine clinical conditions. Because the study was not designed to determine mechanistic synergy, observed reductions in combined-use groups are presented as add-on field performance rather than evidence of synergistic interaction.