Study on Dual Light Source Measurement of SO2，NO and NO2 Based on Differential Optical Absorption Spectroscopy
DA Yao-dong1, 2, 4, SHI Teng-da2, 4, WANG Zhao2, CHANG Yong-qiang2, 3, 4, LI Bing-qian5, GAO Jie5, ZHANG Yun-gang5
1. Xi'an Jiaotong University, Xi'an 710049, China
2. China Special Equipment Inspection & Research Institute, Beijing 100029, China
3. Key Laboratory of Special Equipment Safety and Energy-saving, State Administration for Market Regulation, Beijing 100029, China
4. State Key Laboratory of Low-carbon Thermal Power Generation Technology and Equipments, Beijing 100029, China
5. Department of Instrument Science and Engineering, School of Electrical Engineering, Yanshan University, Qinhuangdao 066004，China
Abstract：The SO2 and NOx emitted from boilers significantly impact air quality, and the accurate detection of their emission concentrations is crucial for environmental protection. Ultraviolet differential optical absorption spectroscopy (UV-DOAS) has become an important technique for detecting SO2 and NOx emissions due to its advantages, such as high sensitivity and strong anti-interference capability. Normally, portable detection devices of SO2 and NOx emissions use deuterium lamps as light sources. However, the mutual interference between NO and NO2 is unavoidable within the spectral range (180~400 nm), and the detection accuracy is reduced. This paper proposes a dual-light source detection method based on differential absorption spectroscopy of SO2, NO, and NO2 concentrations. The high-pressure deuterium lamp and LED are combined to extend the spectral range, and polynomial fitting, wavelet filtering, and least squares method are used to retrieve concentrations from spectral data in the ranges of 295~305 nm (SO2), 220~230 nm (NO), and 425~450 nm (NO2). Linear corrections are implemented for high-concentration deviations of SO2 and NO and low-concentration NO2 to achieve high-precision quantitative analysis of single-component gases across a wide concentration range. Finally, a mixed gas spectral resolution model was established to address the spectral overlap between SO2 and NO in the 220~230 nm range, then enables simultaneous concentration detection of mixed gases within ranges of 0～1 000 ppm (SO2), 0～500 ppm (NO), and 0～500 ppm (NO2). The lowest detection limits of these three gases were 0.394, 0.30, and 0.78 ppm respectively, with a relative uncertainty of 1.00%.
笪耀东，石腾达，王 钊，常勇强，李冰倩，高 杰，张云刚. 基于差分吸收光谱技术的双光源SO2、NO和NO2浓度检测研究[J]. 光谱学与光谱分析, 2025, 45(08): 2140-2148.
DA Yao-dong, SHI Teng-da, WANG Zhao, CHANG Yong-qiang, LI Bing-qian, GAO Jie, ZHANG Yun-gang. Study on Dual Light Source Measurement of SO2，NO and NO2 Based on Differential Optical Absorption Spectroscopy. SPECTROSCOPY AND SPECTRAL ANALYSIS, 2025, 45(08): 2140-2148.
