Study On Key Technology Of The Nitrogen Oxides Analyzer Based On Chemiluminesce

Environmental pollution is one of the serious problems resulting from industrialization, which is negatively influencing human beings. In recent years, alongside with rapid development of our national economy, more and more motor vehicles are found running in cities, and consequently nitrogen oxides in the atmosphere is becoming the main pollutant in most big cities, which threatens people's health.The society gives more and more attention to monitoring atmospheric pollution. Monitoring networks well planned in cities that are able to provide immediate response for researchers plays a very important role in clearing as well as cleaning the atmosphere. But nowadays, expensive and hard to maintain, most NO_x analyzers demanded at home are imported from abroad, which blocks the popularization of NO_x analyzer. And prevention and cure of atmospheric pollution is thus compromised. The project "Domestic Research & Production of NOx Auto-Monitoring System for Monitoring Atmospheric Quality" by the Environmental Protection Agency of Guangzhou is shouldered by Professor He Zhenjiang and Professor Yang Guanling from the modern optical lab of the school of physics and telecommunication engineering SCNU and Mr. Wu Chunlong from Guangzhou Research Institute of Environmental Protection. The job done by the scholars, who will head more researchers of pioneering spirit to the smashing of monopolization in terms of technology imported, plays a very important role in developing our industry of environmental protection instruments.With its main attention to Chemiluminescence, one of the popular ways available for us to detect NO_X at present, the thesis makes use of photon counting formula based Chemiluminescence, with which NO concentration can be detected; analyzes the systematic parameter that can affect detection sensitivity of Chemiluminescence and makes an introduction of the designing of key frameworks, components and some circuitry hardware. The job done above is combined with an exploration for some essential matters such as the changeable dark counts background in the system, the lowering of PMT temperature, the optimized refit of ozonizer involved in the very job, the mechanism underlying the occurring of O₃ background and the simulation of experimental data.We have gained a lot of dependable data from debugging sample machines. The conclusive analysis of the data leads out the following rule: the linearity between NOconcentration and photon counting rate exists when the system is in good condition. In fact, all capabilities of the sample machine are qualified enough to meet the detection of nitrogen oxides in the atmosphere.Finally, I acknowledge the completion of this thesis depends very much on the achievements by other colleagues in my lab.