High‐Precision CO 2 Detection System Based on Gas Filtering Related Nondispersive Infrared Technology

ABSTRACT Accurate and reliable detection of low‐concentration carbon dioxide (CO₂) is crucial for environmental monitoring, industrial process control, and medical diagnostics. A highly sensitive CO₂ detection system has been developed based on the gas filter correlation nondispersive infrared (GFC‐NDIR) technology, which is a cost‐effective technological variation of NDIR. The system exploits the strong absorption characteristic of CO₂ molecules at 4.26 μm in the mid‐infrared spectral region. The sensitivity and selectivity of the developed sensor system were significantly enhanced through optimized narrow‐band optical filtering and the use of a low‐cost broadband light source. A high‐precision gas filter correlation wheel serves as a reference channel, effectively suppressing interference from source fluctuations, optical component drift, and cross‐sensitivity from other environmental gases. The system achieves a minimum detection limit (MDL) of 3 ppb for CO₂ under ambient temperature and pressure conditions, with a response time of less than 30 s and long‐term stability of better than ±2% of full scale per 24 h. The developed system holds broad application prospects in areas including environmental greenhouse gas flux monitoring, enclosed space safety warning, and high‐purity gas quality control.