Laser & Optoelectronics Progress, Volume. 61, Issue 5, 0530004(2024)
Indoor CO2 Online Monitoring Based on Open-Path Tunable Diode Laser Absorption Spectroscopy
To investigate the variation in indoor carbon dioxide (CO2) volume fractions and their relationship with human activities, this study designs an open-path tunable diode laser absorption spectroscopy (TDLAS) sensing system to monitor indoor CO2 volume fractions. A distributed feedback (DFB) laser with a central wavelength of 2004 nm is employed as the excitation light source to measure the R(16) characteristic absorption line of carbon dioxide. The Levenberg-Marquardt method of nonlinear least squares fitting is employed to fit the measured spectra, allowing for volume fraction measurements without requiring calibration. Comparative measurements with a commercial XENSIVTM PAS CO2 sensor yield a high correlation (R2=0.89). The results indicate that the daily average indoor CO2 volume fraction is 4.63×10-4, slightly surpassing outdoor levels, whereas the fluctuation range of indoor CO2 volume fraction within a day is 3.86×10-4?5.66×10-4. Indoor CO2 volume fraction is volume fractions influenced by ventilation and indoor human activities, and the daily volume fraction trends are highly correlated with working hours. At a personnel density of 0.005 persons/m3, the growth rate of CO2 volume fraction is measured at 2.3×10-5 h-1. Therefore, timely ventilation is recommended for crowded indoor environments to prevent elevated CO2 volume fractions that may cause discomfort.
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Qi Huang, Qing Wang, Kaitao Wang, Congshan Wang, Ruyue Cui, Hongpeng Wu, Lei Dong. Indoor CO2 Online Monitoring Based on Open-Path Tunable Diode Laser Absorption Spectroscopy[J]. Laser & Optoelectronics Progress, 2024, 61(5): 0530004
Category: Spectroscopy
Received: Nov. 29, 2023
Accepted: Jan. 3, 2024
Published Online: Mar. 1, 2024
The Author Email: Cui Ruyue (cuiruyue@sxu.edu.cn), Dong Lei (donglei@sxu.edu.cn)