中文摘要：

NO2气体吸收特性研究是光谱法在线监测的基础，而被测环境压力和温度等因素对吸收截面有不同程度的影响。以卤素灯为可见光连续光源，用0．5nm分辨率（FWHM）光纤光谱仪研究了在室温293K、绝对压力0．01～0．5MPa时NO2的吸收特性。当NO2分压不变，随外加气体N2的加入总压升高时，吸收截面有所下降；当NO2分压、总压同时改变，在总压小于0．25MPa时吸收截面的变化可以忽略；在435—500nm波段NO2吸收截面定积分值与文献比较，数值差异不超过5％，无频移现象出现。利用差分吸收光谱法（DOAS）测量火电厂等固定污染源NO2排放浓度时，压力在4-10kPa范围内波动对差分吸收特性的影响可以忽略。图9表1参10

英文摘要：

Research on absorption characteristic of NO2 constitutes the foundation for the development of online monitoring by spec degree, trum analysis, but factors like pressure and temperature of the monitored environment effect, though different in the absorption cross-section. The absorption characteristics of NO2 has been studied, under an absolute pressure of 0.01-0.5 MPa and an ambient temperature of 293 K, by using a halogen lamp as the continuous visible light source and an optical fiber spectrograph of 0.5 nm resolution capability. If the partial pressure of NO2 is kept constant, the absorption cross-section reduces with increasing total pressure, caused by the addition N2 ; in case both partial and total pressure are kept constant, variation of the absorption cross-section may be neglected as long as the total pressure is below 0.25 MPa ; the integrated absorption cross-section of NO2 for the wavelength range 435-500 nm doesn＇ t deviate more than 5 % from values already published and no frequency shifts are observed. When the concentration of NO2, emitted by some fixed sources of contamination like fossil fired power plants, is being measured by differential optical absorption spectroscopy （DOAS）, the effect of ± 10 kPa pressure fluctuations on differential absorption property may be neglected Figs 9, table 1 and refs 10.