Low-Cost Tracer Gas Sensor for Building Ventilation

The accurate assessment of Indoor Air Quality is crucial for occupant health, yet traditional methods for evaluating ventilation rates, such as tracer gas techniques using photoacoustic spectroscopy (PAS), face limitations in cost, logistics, and response time. This study presents the development and validation of a low-cost, fast-response sensor system for tracer gas measurement, capable of detecting multiple gases. The sensor employs a Non-Dispersive Infrared (NDIR) detector with wireless communication based on the asynchronous Bleak protocol, enabling spatially resolved IAQ monitoring. Laboratory validation using SF6 as tracer gas in a small volume of 40 liters and against the PAS reference device demonstrated an accuracy within ±20% for ventilation rates between 1 and 7 air changes per hour (ACH). Unlike PAS, which provides one measurement per minute, the low-cost sensor captures up to 50 readings per second, offering superior tracking of transient ventilation events and dynamic IAQ variations. The results suggest that this system provides a practical alternative for real-time IAQ monitoring, supporting energy-efficient and health-conscious building management.