Studying Of Air Quality Monitoring System Based On FTIR

Along with the development of economic and the improvement of technique and living level, the subject"Air quality"has gained more attention than ever all over the world.At present, most of the traditional systems operated have some disadvantage for real time air quality monitoring. So we try to develop a set of extractive air quality monitoring system based on Fourier Transform Infrared (FTIR) spectroscopy, which can in-time measure gaseous air pollutant concentrations.As the basic research of FTIR applied in low-concentration range (ppm to ppb) gas measurements, this paper provided the gas concentrations retrieving theory and approach. Many measures are utilized to overcome the disadvantage of poor signal intensity. This investigation discussed some issues in details, such as the system configuration, the long path gas absorption cell, how to acquire proper reference spectra, and the collection of optimal wavenumber range. Through spectral analysis, two methods are used to acquire the concentrations from sample spectra. One is spectrum subtraction; the other is criterion spectra fit. The result errors can be controlled in±10%. Some experiments have been designed to get the product of concentration and path length, the optimal path length for the system, and the performance evaluation.Specially, two-dimensional infrared correlation spectroscopy (2D-IR) technology is used in optimal wavenumber range analysis, which gives a good result according data process experiment.