Ultraviolet-germicidal-irradiation-based reduction of airborne bacteria in pulmonary function test rooms: a quality...

Pulmonary function test (PFT) rooms involve frequent patient turnover and can generate respiratory aerosols during forced expiratory manoeuvres. This quality improvement (QI) project evaluated observed changes in culturable airborne bacteria (CAB, cfu/m³) under routine clinical operation when ultraviolet germicidal irradiation (UVGI)-related engineering controls were applied singly or in combination, to inform pragmatic infection-prevention options for PFT rooms.

CAB was sampled by impaction at two fixed locations in the PFT room using a consistent protocol with repeated measurements. The baseline/control condition was defined as routine operation with supplemental devices OFF (ceiling UV-C OFF and portable air-circulation UV sterilizer OFF) under the specified heating, ventilation, and air conditioning (HVAC) setting, and intervention conditions were assessed using the same protocol. Lobby measurements were used only as contextual building-environment comparators.

The combined operation of ceiling UV-C, the portable air-circulation UV sterilizer, and HVAC yielded the lowest observed CAB, while ceiling UV-C alone produced the largest reduction among single interventions in this setting. Representative isolates included common skin/environmental taxa (e.g., Staphylococcus hominis), consistent with human occupancy and resuspension.

In this real-world QI evaluation, UV-C-containing interventions were associated with lower culturable airborne bacterial counts in the PFT room, with the lowest observed values under combined engineering controls. These findings should be interpreted as culture-based room-level observations under routine workflow conditions, not as evidence of complete air disinfection or respiratory pathogen reduction.