NO2 detection based on laser spectrum differential method

In order to analyze the relationship between spectra and gas volume fractions of NO2 which is one of the main pollution gases, laser whose center wavelength was located in the peak of NO2 absorption was chosen as light source and a gas spectra detection system was built. The spectrum was analyzed according to Lambert-Beer law, using time-sharing differential method, comparing with authoritative database and considering the spectral area and other factors. The data were fitted by the least squares method and the relationship curve between NO2 absorption spectra and NO2 volume fractions was obtained. The data of volume fractions was inversed and the error was analyzed. The experimental results agree well with the theoretical analysis. The research value and the application value of the experimental system are verified.