The relative performance of NDIR-based sensors in the near real-time analysis of CO2 in air

In this study, the reliability of NDIR-based sensors was explored by evaluating the comparability between measurement systems in the near real-time analysis of CO2. For this purpose, replicate analyses were performed using sensors of two different model types (H-550 and B-530, ELT Company, Korea). Three replicate data of each sensor type collected continuously by side-by-side analysis in three second intervals (a duration of 304 hour) were evaluated for the relative performance of NDIR sensors. The reproducibility of sensors, when assessed by relative standard error (RSE%) values of all sensor units, showed moderate changes with time with the overall mean of 2.33%. When CO2 measurements from all NDIR sensor units were evaluated by correlation analysis, the results showed strong comparability, regardless of the model type. The overall results of this study suggest that NDIR sensors are reliable enough to produce highly comparable data at least in a relative sense.