Study On Long-Range Differential Optical Absorption Spectrometry For Atmosphere Monitoring

In recent days, the air pollution has become a serious problem and much attention has been paid to the research of this subject. For this reason, some new methods are needed to measure the concentrations of pollutants in the atmosphere. In this dissertation, the characteristics of some important pollutants in the air and some pollution phenomena, such as photochemistry smog, in the atmosphere are firstly presented. The produce of this phenomenon and the roles of constituents in this process are also discussed. A novel method for measuring the air pollutants—Differential Optical Absorption Spectrometer (DOAS) and its application in real measurement are described. The theory and the techniques for DOAS system are also presented in this thesis. Numerical filters and least-square fitting are successful applied in the processing of measurement spectrum, so that the concentration of trace gases in the atmosphere could be retrieved with high precision. The molecular conversion between different kinds of pollutants and the relationship between photochemistry reaction and meteorologic factors are discussed also during analyzing of the data, and it is found that the measurement result coincides with the theoretical analysis. At the end of thesis, farther applications and developments of DOAS system are also presented.