CO2 concentration testing as a quick estimate of natural ventilation effectiveness in primary healthcare: experience in war-affected, resource-limited settings

Ventilation remains an important component of infection prevention and control programmes. Natural ventilation, as the most affordable measure to control airborne transmission of pathogens, is a crucial area of focus. However, applying natural ventilation encounters challenges in routine practice, especially in emergencies. This study, which aimed to review the most efficient natural ventilation regimen, was performed in Autumn 2023 in two heavily war-affected primary care facilities in Ukraine. The study demonstrated the operational advantage of a regimen built upon a simple approach, where personnel opened windows only after observing an increased CO₂ concentration. This solution has obvious disadvantages, being reactive rather than proactive and requiring continuous monitoring of CO₂ concentration; it turned out to be more acceptable to busy healthcare workers than regimens developed explicitly for each office, considering ventilation rate and workload. Patients' complaints about feeling cold in the offices may be a substantial obstacle to the formal use of natural ventilation. Reported results were considered an acceptable temporary compromise for initiating a natural ventilation policy. Further improvement will require personnel training and raising awareness about reasonable prevention interventions for airborne pathogens among patients.