Full classrooms or busy meeting rooms – the risk of infection with the coronavirus is increased, especially indoors. Retrofitted exhaust air or ventilation systems can help reduce the concentration of potentially infectious particles. But how reliably does such a system work? Can the system be controlled automatically by combining it with particle sensors? A team of researchers at the Technische Universität Kaiserslautern (TUK) is looking into this. The team will be presenting its project at the Achema process industry trade fair in Frankfurt from 22 to 26 August at the Rhineland-Palatinate research stand (stand A35, hall 6).