We analysed the effectiveness of plasma treatment on airborne bacteria and surface counts on a 14-day intervention with plasma air treatment within a 4-bedded bay in an adult respiratory ward at Cork University Hospital. 100L air samples were collected twice daily every weekday for 4 weeks, with settle plates and surface swabs. The plasma treatment did not produce an effect on airborne bacteria and fungi which was detectable by culture. We cannot exclude that culture-based sampling may be insufficiently sensitive to detect an effect, or that the duration of the study was insufficient for plasma treatment to affect a complex environment.