Studies On The Air Pollution Detection By Employing A Scanning Scheimpflug Lidar

With the development of the times and the progress of science,people's lives have become more and more convenient and fast.However,just as everything has two sides,the development of science and technology not only brings people a rich material life,but also triggers a series of new social and environmental problems.In recent years,air pollution has become a major issue concerning national happiness and health.Atmospheric pollutants mainly include particulate matter?PM2.5,PM10,etc.?,nitrogen oxides,ozone,sulfides and volatile organic compounds.Gases such as NO₂ and SO₂ can cause acid rain,ozone can induce photochemical smog,and atmospheric particulate matter can cause respiratory diseases and affect lung health.These atmospheric pollutants not only seriously endanger human health,affect the ecological environment and climate change,but also cause huge losses to economic production activities.According to the latest China Environmental Ecology Report,among the 169 counted pollutants in various cities,the proportion of PM2.5 reaching super-secondary pollution is 82.8%,and the proportion of reaching second-level pollution is17.2%.The pollution status of other pollutants Not to be ignored.Among the 338 cities in the statistics,the number of days with pollution exceeding one year reached 64.2%.Therefore,there is an urgent need for powerful technical means to carry out atmospheric environment monitoring.Lidar technology has the characteristics of wide detection range,high spatial and temporal resolution,and strong anti-interference ability.It can effectively make up for the deficiencies of traditional point-based monitoring technology,and provides a new powerful monitoring method for atmospheric pollution monitoring.SLidar?Scheimpflug Lidar?is a new type of atmospheric remote sensing detection technology developed in recent years.It uses a diode laser as a laser light source and a CMOS/CCD image sensor as a detector.The distance-resolved detection of atmospheric backscattered signals is realized in the following,which has important application value in the field of atmospheric environment monitoring.In response to the urgent need for lidar technology for atmospheric pollution monitoring,this paper carried out research work on the development,application and data inversion analysis of the scanning SLidar system.The scanning SLidar system uses a continuous wave high power 808 nm diode laser as the light source.The laser beam is collimated by an F6 lens with an aperture of 100 mm and emitted into the atmosphere.The aerosol and gas molecules in the atmosphere will scatter and absorb the laser light.The backscattered light signal is collected by a F5 lens with a diameter of 150 mm,and is detected by a CMOS image sensor placed at an angle of 45°and passed to the data.The computer can finally obtain the distance-resolved laser atmospheric echo signal.This article first describes the current status of atmospheric environmental pollution,and then introduces the domestic and international research status of the traditional pulse scanning atmospheric lidar and Slidar in the monitoring of atmospheric environment.The second chapter introduces the physical effect of the interaction between the atmosphere and the laser,which is mainly divided into elastic scattering and inelastic scattering,and explains the basic working principle,system structure and corresponding data processing method of atmospheric lidar.The third chapter elaborated on the basic structure and working principle of the 808 nm scanning SLidar system developed in this paper.At the same time,the system was used to carry out fixed-azimuth atmospheric measurement experiments,and the data inversion results were compared and analyzed with monitoring station data.,Preliminary verification of the system's ability to detect atmospheric aerosols.The fourth chapter mainly introduces the research work of the atmospheric pollution scanning measurement carried out on the campus of Dalian University of Technology on the surrounding 5 kilometers,analyzes and discusses the results of atmospheric pollution horizontal scanning and vertical scanning to measure the aerosol vertical profile.Studies have shown that the scanning SLidar system can identify the distribution and changes of local pollutant emissions through the horizontal scanning measurement of the urban atmosphere,while the vertical scanning measurement can effectively analyze the spatial and temporal evolution of the vertical structure of the boundary layer aerosol.