研究了利用差分光学吸收光谱(DOAS)技术测量烟道污染气体SO₂的方法。介绍了差分吸收光谱的基本原理和数据处理方法。讨论并分析了测量过程中光谱波段的选择。以氘灯作为光源，分别利用光谱分辨率为0．6nm、0．7nm和1．8nm的光谱仪对SO₂的吸收光谱进行了测量，分析了光谱分辨率对测量结果的影响。DOAS方法分析的是吸收光谱的高频部分，避免了烟尘、水汽等对测量结果的影响，可以利用差分光学吸收光谱对烟道污染气体进行检测。

The methodology is described for detection of SO₂ in flue gases by differential optical absorption spectroscopy(DOAS). The basic principle and data analysis method are introduced. The selection of wavelength range during the measurement is also discussed. Measurement of SO₂ was carried out at different spectral resolution(0.6 nm, 0.7 nm, 1.8 nm) respectively. The influence of spectral resolution on the result was analyzed. DOAS method analyzes high-frequency part of absorption spectroscopy, and it can avoid influences of the interferences such as fume, vapor. It is proved to be a good method for detecting the flue gas.