A laser induced fluorescence instrument for measuring tropospheric NO2
A laser induced fluorescence instrument for measuring tropospheric NO2
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激光诱导荧光对流层NO2测量仪
DOI：
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发表时间：
1997
期刊：
影响因子：
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通讯作者：
W. Brune
中科院分区：
文献类型：
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作者：
C. Fong;W. Brune
二氧化氮（NO2）是大气化学中的一种必需气体，几乎总是通过一种技术间接测量：将NO2光解成NO，然后检测产生的NO。然而，在低NO2体积混合比下，光解引入了伪信号，使NO2信号的提取复杂化。一种新型的激光诱导荧光直接测量对流层二氧化氮的仪器样机。该仪器测量的大气荧光光谱与参考电池中二氧化氮在565.1 ~ 565.2 nm波长范围内的荧光光谱相匹配。这种匹配表明来自其他化学物质的荧光不会干扰测量。该原型目前的检测极限为2.5分钟内280万亿分之一（pptv），绝对不确定性为±15% （2σ置信度）。这种检测极限可以通过更好的光学滤波和更多的激光功率来提高，目前对于城市空气条件是足够的。
Nitrogen dioxide (NO2), an essential gas in atmospheric chemistry, is almost always measured indirectly with just one technique: photolysis of NO2 to NO, followed by detection of resulting NO. However, the photolysis introduces artifact signals that complicate the extraction of the NO2 signal at low NO2 volume mixing ratios. A new prototype instrument uses laser induced fluorescence to measure tropospheric NO2 directly. The atmospheric fluorescence spectra measured with this instrument match the fluorescence spectra of NO2 in a reference cell over the wavelength range 565.1–565.2 nm. This match indicates that fluorescence from other chemical species is not interfering with the measurements. The prototype’s current detection limit is 280 parts per trillion (pptv) in 2.5 min with an absolute uncertainty of ±15% (2σ confidence). This detection limit, which can be improved with better optical filtering and more laser power, is currently adequate for urban air conditions.