Research For The Key Technology Of The City Dust On-line Monitoring System

The atmospheric particulate matter concentration(PM10 and PM2.5)has a profound influence on people's health and every aspects of daily life.With the pushing of China's urbanization process and the municipal infrastructure construction,the dust source has made prominent contributions to the atmospheric particulate matter pollution.The available methods and instruments,which are used to monitor the particulate matter mass concentration,mostly adopt the extraction of sampling at a single location,as for the dust site monitoring between a long distance in a wide range,there is no simple and reliable low-cost implementation plan,and there are some limitations in actual applications.In this paper,the city dust on-line monitoring system is designed,it uses the light path structure which can make an adjustable range,combined with the hardware circuit and software algorithm,implements the particulate mass concentration measurement in open and large space,it provides a rapid and real-time method for the mass concentration measurement of field monitoring.In this paper,the application and implementation of the total light scattering method were studied to monitor particulate matter mass concentration in large areas,according to this goal,the main work include:1.On the basis of total light scattering model,the city dust correlation measurement system was developed.According to the Beer-Lambert law and Mie scattering theory,the system uses an independent model algorithm to approximate the actual particle size distribution,combined with the theoretical model to determine the actual parameter requirements;2.Design the measurement system with reflection type light path structure,it improves the system's stability,reduces the difficulty of adjustment and improves the response characteristics.In order to implement the measurement system stably and accurately,it weakens the interference of background light by means of structural design and modem technology,adopts light intensity feedback to compensate intensity fluctuation of the light source;3.The experimental platform of the city dust on-line monitoring system was builded to verify the system's stability for long hours,the sensitivity and how the outside temperature variation will affect the measurement system.