Improved analyzer for nitrogen dioxide by laser-induced fluorescence technique

A compact, fast-response instrument for measuring atmospheric NO2 by single-wavelength excitation laser-induced fluorescence (LIF) technique was improved. A single-pass alignment of a more powerful, pulsed laser was utilized to realize the pptv (=10−12 by volume) of the limit of detection (LOD). As a result, the LOD reached 1.8 pptv for 1-min averaging (S/N=1). To determine the instrumental zero accurately, interference by particles was cancelled out utilizing an NO2 scrubber tube coated with a mixture of titanium dioxide (TiO2) and hydroxyapatite. Consequently, it was confirmed that the combination of the improved single-wavelength LIF instrument with the scrubber was reasonable for measuring atmospheric NO2.