Laser-induced fluorescence instrument for measuring atmospheric SO2
Laser-induced fluorescence instrument for measuring atmospheric SO2
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DOI：
10.1016/j.atmosenv.2005.02.023
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发表时间：
2005-06
影响因子：
5
通讯作者：
Y. Matsumi;H. Shigemori;Kenshi Takahashi
中科院分区：
文献类型：
--
作者：
Y. Matsumi;H. Shigemori;Kenshi Takahashi
报道了一种利用激光诱导荧光(LIF)技术在220 nm附近测量大气SO2的高灵敏度探测系统。用三次谐波泵浦的可调谐宽带光参量振荡器(OPO)的二次谐波作为荧光激发源。将激光波长交替调谐到SO2光吸收光谱中220.6 nm和220.2 nm处的峰值和底部波长，并利用这两个波长的差值信号提取SO2浓度。该方法对SO2有很好的选择性，避免了样品空气中SO2以外的荧光或颗粒物的干扰。研制的SO2仪的灵敏度为5pptv(60s)，S/N=2。该检测系统的实际性能在郊区进行了测试。将该仪器与商用的氙灯激发荧光检测仪器进行了比对。两台仪器之间的相关系数高达70ppbv。LIF测量值与商用仪器测量值之间有很好的线性关系。
We report on the development of a high-sensitive detection system for measuring atmospheric SO2using a laser-induced fluorescence (LIF) technique at around 220nm. Second harmonics of a tunable broad-band optical parametric oscillator (OPO) pumped by the third harmonic of a Nd:YAG laser is used as a fluorescence excitation source. The laser wavelength is alternatively tuned to the peak and the bottom wavelengths in the photoabsorption spectrum of SO2at 220.6 and 220.2nm, respectively, and the difference signal at the two wavelengths is used to extract the SO2concentration. This procedure can give a good selectivity for SO2and avoid interferences of fluorescent or particulate species other than SO2in the sample air. The SO2instrument developed has a sensitivity of 5pptv in 60s and S/N=2. The practical performance of the detection system is tested in the suburban area. The inter-comparisons between the LIF instrument and a commercial instrument using Xe flash lamp excitation for the fluorescence detection have been performed. The correlation between two instruments is measured up to 70ppbv. A good linear relationship between the LIF measurements and commercial instrument measurements is obtained.