"We have to freeze or be deafened": A survey on the effectiveness of CO2 alarms in university spaces

Rising awareness of indoor air quality (IAQ) and its associated health impacts has driven the uptake of sensor-based interventions to encourage ventilation, yet whether these reliably prompt consistent occupant action remains unclear. This study examines how CO₂ sensor alarms influence ventilation behaviour in university spaces and identifies the psychological and contextual factors shaping responses. A survey of 100 occupants at the University of Sheffield assessed awareness, interpretation, and responses to CO₂ alarms. Participants were aware of the purpose of alarms but uncertain about their accuracy, location, and appropriate response to alerts. Comfort and health concerns motivated action, whereas low urgency and environmental constraints hindered it. COM-B analysis shows awareness alone is insufficient where contextual barriers persist. The findings inform recommendations to improve alarm design and user engagement, highlighting the need for systems to go beyond detection and actively support occupant action.