Abstract
We developed the instrument to measure ambient NOx concentrations in ppt level by laser induced fluorescence technique. Diode laser pumped solid state (DPSS) laser was used as the excitation source for NO2 molecules its self and dye laser for NO3 detection. We employed FAGE (fluorescence assay of gas expansion) technique to detect both NO2 and NO3 radicals. We achieved the ultra high sensitive NO2 analyzer whoes LOD (limit of detection) was 1.8 ppt. We brought the instrument to the Rishiri island Hokkaido and tested the utility and found the high potential for the practical use. We also developed NO3 sensor as an extension of NO2 analyzer. We employed tunable dye laser as the excitation source for NO3 molecule at 623 nm band. Successfully we applied NO3 analyzer to detect N205 at the campus of Tokyo Metropolitan University in March 2004 because N205 was easily thermally decomposed into NO3 and NO2.
