Impact of Filtration Conditions on Air Quality in an Operating Room

The aim of this study was to assess the impact of ventilation and filtration conditions on particle concentrations in an orthopedic operating room. Total particle, viable particle, and CO2 concentration were measured under three different situations, namely before air filter replacement, after air filter replacement, and in an operating room with a new air conditioning system. Before air filter replacement, the mean values of airflow, total particle concentration, and viable particle concentration were 706 m3/h, 15.0 × 106 ± 4.0 × 106 particles/m3, and 57 CFU/m3, respectively. After replacement, the airflow increased to 1954 m3/h, and total and viable particle concentrations decreased to 0.4 × 106 ± 0.2 × 106 particles/m3 and 24 CFU/m3, respectively. In the room with a new air conditioning system, the airflow was 2051 m3/h, and total and viable particle concentrations were 0.3 × 106. ± 0.1 × 106 particles/m3 and 15 CFU/m3, respectively. The CO2 levels were 663 ppm (before), 659 ppm (after), and 574 ppm (new room). The results showed that inappropriate or no maintenance of filters in an air conditioning system had significant negative effects on indoor air quality in operating rooms. Air conditioning systems operating with saturated filters can be affected by pressure drop, which can lead to a reduction in airflow, thereby resulting in an increase in the average total particle and viable particle concentrations and the risk of infection in operating rooms. However, the results showed that the CO2 concentration was not affected by the filter replacement.