Low-cost & fast-response multi-tracer multi-point gas sensing network for ventilation and interzonal flows measurements

The assessment of ventilation performance and interzonal airflows is essential both for ensuring indoor air quality (IAQ) and for understanding the risk of airborne cross-infection in buildings. Conventional tracer gas methods, typically relying on photoacoustic Gas Analyzers (PGA), remain limited by high costs, logistical complexity, and restricted temporal resolution. This study introduces a novel low-cost, fast-response sensing system designed for multi-tracer and multi-spot applications. The platform integrates Non-Dispersive Infrared (NDIR) detectors and wireless communication, enabling the simultaneous monitoring of different tracer gases—sulfur hexafluoride <ns0:sc>(SF6), </ns0:sc>propane (C3Hs), and carbon dioxide (CO2)—across multiple zones. The use of multiple tracers allows the characterization of interzonal mass exchange pathways, while the distributed sensor network provides spatially resolved data with high temporal resolution (theoretically, up to 50 Hz). Laboratory validation against reference PGA and anemometric data confirmed measurement accuracy within ±20% for ventilation rates between 1 and 10 air changes per hour (ACH). Beyond traditional single-zone assessments, the proposed system demonstrates the capability to capture transient airflow phenomena and quantify interzonal exchange rates with a single equipment, offering a practical and scalable tool for real-time IAQ monitoring, ventilation effectiveness evaluation, and infection risk assessment in buildings.