Evaluation and environmental correction of ambient CO2 measurements from a low-cost NDIR sensor
- 1Department of Atmospheric and Oceanic Science, University of Maryland, College Park, MD 20742, USA
- 2Earth System Science Interdisciplinary Center, University of Maryland, College Park, MD 20742, USA
- 3National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
- 4Air Resources Laboratory, National Oceanic and Atmospheric Administration, College Park, MD 20740, USA
- anow at: Department of Geography, University of Colorado at Boulder, Boulder, CO 80309, USA
Abstract. Non-dispersive infrared (NDIR) sensors are a low-cost way to observe carbon dioxide concentrations in air, but their specified accuracy and precision are not sufficient for some scientific applications. An initial evaluation of six SenseAir K30 carbon dioxide NDIR sensors in a lab setting showed that without any calibration or correction, the sensors have an individual root mean square error (RMSE) between ∼ 5 and 21 parts per million (ppm) compared to a research-grade greenhouse gas analyzer using cavity enhanced laser absorption spectroscopy. Through further evaluation, after correcting for environmental variables with coefficients determined through a multivariate linear regression analysis, the calculated difference between the each of six individual K30 NDIR sensors and the higher-precision instrument had an RMSE of between 1.7 and 4.3 ppm for 1 min data. The median RMSE improved from 9.6 for off-the-shelf sensors to 1.9 ppm after correction and calibration, demonstrating the potential to provide useful information for ambient air monitoring.