Reconstruction Of Spatial Concentration Of Gaseous Pollutants In The Atmospheric Environment

This paper reconstructed distribution of gas concentration by Open-path FourierTransform Infrared Spectrometer in combination with Computed Tomography. The majorcontent was discussed as follows:1, Curve fitting technique was applied into reconstructing gas concentration distribution along one beam path. Comparing the results from the six methods (5^th, 6^th, 7^th, 8^th and 9^th least-square polynomial curve fitting, and cubic-spline interpolation), it could be known that the 7^th least-square polynomial curve fitting performed better than others in the reconstruction results.2, A rapid reconstruction algorithm was developed based on Bi-cubic B-spline surface technique. This algorithm could map gas concentration effectively in a two-dimensional plane. By comparison with SBFM algorithm, this rapid algorithm could get accordant results with SBFM algorithm about the reconstructed maximum concentration and its corresponding position. The most advantage of this rapid method lied in computing speed being just 0.719s, faster than the value of SBFM, which was 224s.3, This paper also researched the performance of this rapid algorithm in reconstructing concentration distribution of acetone, methylene chloride, and chloroform in the measuring plane. BP-ANN technique was utilized to analyze the spectrogram of the mixed gas before reconstruction by this rapid algorithm. The results illustrated that this method worked well in the reconstruction of the maximum concentrations and its corresponding positions about the three VOCs.