Absorption Spectrometry Detection System. Flue So <sub> 2 </ Sub> Difference

UV-VIS-differential optical absorption spectroscopy (DOAS) has become a widely used method to measure gases in stack and the atmosphere. This simultaneously measures the concentrations of multiplicate pollutants. Their concentration is retrieved by a numerical analysis of the absorption spectra, which often are a combination of overlapping absorption structures of several gases. A new analysis procedure was developed, to determine their concentrations, to estimate the error of the concentrations and to consider the uncertainty gases. As the main factor affected the precision of the DOAS, the absorption cross section and its measurement theory was analyzed. A new measurement setup was brought forward, and through which the absorption cross section of SO₂ was measured. The interferences owing to the defects of the grating and stray light in the spectrometer of DOAS system cause the extra spectral structure. In order to solve these problems, two methods have been presented in this paper. It has been shown that the error of retrieving the concentration have been reduced in the experiment. Furthermore, this paper studies the typical set up and analysis procedure of a differential optical absorption spectroscopy instrument.This paper is aimed to discuss the foreground of the DOAS technology, and supply some academic and experimental groundwork for the development of such apparatuses basing on DOAS technology.