装置と技術

 

レーザー誘起蛍光法による大気中NO3/N2O5測定装置

Analyzer for Measuring NO3/N2O5 in the Atmosphere
by Laser-Induced Fluorescence Technique

松本 淳・小杉如央・今井秀和・梶井克純
Jun MATSUMOTO, Naohiro KOSUGI, Hidekazu IMAI,
and Yoshizumi KAJII


NO3 and N2O5 are important as intermediates of NOx loss in the nocturnal atmosphere. In this study, laser-induced fluorescence (LIF) technique is applied for measuring NO3 and N2O5 in the atmosphere. A tunable dye laser pumped by a pulsed Nd:YVO4 laser was utilized as an excitation light source. NO3 was excited around its 623-nm absorption peak and the induced fluorescence was detected. For measuring N2O5, thermal decomposition of N2O5 was carried out and then generated NO3 was detected. As a result of improvement and calibration of the instrument, the limits of detection for NO3 and N2O5 reached 4 and 6 pptv, respectively (S/N = 1, 10-min averaging). A measurement test of N2O5 was conducted in the urban atmosphere to check the applicability of the instrument. The LIF instrument is promising to measure atmospheric NO3 and N2O5. This is a successful case of applying a spectroscopic method to the environmental chemistry.


Keywords: LIF, Nitrate radical, Dinitrogen pentoxide, Calibration, Atmospheric chemistry


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