Developed Of A PM_2.5 Detection System Based On Laser Grad Thermal Desorption And Raman Techniques

The dection of fine particles (PM2.5) in the atmosphere has become the hot spot due to the nationwide severe haze weather, GB only relates to PM2.5particle concentration detection at present, however, the technology and equipment about the composition of PM2.5detection is the focus of current reasearch. A large number of toxic gases and particulate matters have been emitted into the atmosphere and organic pollutants that absorbed on fine particle matter can stay in the atmosphere for a long time. The organic pollutants will cause human discomfort reactions occur and result in a bad impact on human health through the respiratory tract, gastrointestinal tract and skin into the body. Thus, the study of the composition and content of organic matter for fine particulate matter has important practical significance. However, the current commonly used methods for extraction of trace organic analysis for PM2.5have the requirement of organic solvent, long sample processing time and high demand of sample. And also these methods do not support online analysis. Based on consideration of the above problems, this study developed a laser grad thermal desorption sample pretreatment and laser Raman spectroscopy system that could directly detect trace organic compounds contained in PM2.5. The combined system has achieved preliminary conclusion, and provides conditions for the subsequent online tracing analysis of fine particles. The main studies done in this dissertation are as followings:1. Briefly introduce the current situation, source and chemical composition of atmospheric pollution particles. Discuss the principle of sample collection, the tradition pretreatment methods and point out the advantages of thermal desorption technology. Introduce the fundamental theory of Raman spectroscopy, the direction and current status of the study about laser Raman spectroscopy.2. Design and implement the overall structure of the LGTD-LRS (Laser Grad Thermal Desorption-Laser Raman Spectrum) control system and hardware construction. Describe the hardware in details with particular focus on the design of the sample chamber and the principle and structure of each functional unit.3. Introduce the implement of system’s software function and realize the design and simulation of fuzzy adaptive controller. 4. Conduct the basic and applied research and complete the automobile exhaust PM2.5gradient analysis and Raman difference spectroscopy spectrum analysis.5. Summary and perspective.