Study On The Relationship Between Visibility And Particulate Matter Concentration In Heavy Fog Monitoring

Visibility data have long needed to traffic meteorological monitoring and warning system,especially when visibility under fog and haze condition is drastically reduced and air pollution often hits dangerous levels in large city.But visibility data have monitored with expensive special equipment currently,the relevant information couldn't show promptly,let alone follow continuous monitoring and tracking.Therefore,there is an urgent need to achieve a breakthrough in the field of visibility monitoring of fog.This paper explores related research according to visibility degradation in fog is due to the light scattering of fog droplets,which are transit from aerosols via activation.Based on the Mie scattering theory,a lot of theoretical researches and experimental investigations have been carried out to measure particle characteristics.These researches show that the particles of different sizes have different optical scattering properties,the meteorological factors,such as wind speed,humidity and temperature,have a great impact on visibility in fog monitoring,it is difficult to study the relationship with the extinction coefficient by observing the particle concentrations with different diameter in the fog.However,It is necessary to conduct a comprehensive calibration of the equipment to establish a reliable regression model.Thus,.it is feasible that visibility inversion level was inverted quantitatively by using of different diameter particles concentration.In this paper,analyzing the method of domestic and foreign research on the relationship between atmospheric visibility and aerosol particles in theory,and considering the influence factors in practical monitoring work,the various theories are summarized to find out a more practical method of visibility measurement.This paper emphasizes the test method at the foundation of theoretical formula derivation,through a large number of statistical regression analysis based on laboratory simulation,combined with field monitoring data,has improved excellently the inversion algorithm in different relative humidity range.Considering strong correlation between PM2.5?particulate matter with diameters less than 2.5?m?,PM₁₀ mass concentration,and visibility,retrieving models can be established.Meanwhile,in order to solve the fog monitoring and prevent haze issues that attract the public attention,the development and design of a low visibility monitoring system have been put forward.Choosing the lower-cost core of computer system based on Arduino,which is a plurality of measurement devices,using the RS485 interface to extend GPRS transmission module and remote monitoring center for communication by the LabVIEW graphical software,the software system of the host computer is developed.This monitoring system can achieve the function of real-time multiple terminal acquirement,data analysis,the switching of the measurement mode,and the remote control function.The result of the test indicates the system has typical characteristic of simplify interface,convenient operation,lower consumption,and high levels of reliability and flexibility.Finally,in term of deviation,by analyzing the error source of monitoring system,several methods have been applied to reduce error,the paper provides the basis for the improvement and perfection of the system in the future.