Performance Evaluation And Application Study Of Portable Particulate Particle Spectrometer

The particle concentration distribution and size of atmospheric particles is the basis for studying the pollution of atmospheric particulate matter.However,most of the traditional particulate particle diameter distribution measuring equipment is large and high cost.With the development of technology,small optical particulate counter is increasingly rich,and the cost is gradually decreasing.The application of miniaturized and portable particle spectrometers has brought new opportunities for research on the characteristics,sources,and impacts of related particulate matter.In this study,a portable particle spectrometer SDS029(domestic)was selected for performance evaluation and application test research to explore the feasibility of miniaturized equipment applied to particulate matter monitoring in the road environment.Performance evaluation includes the accuracy,consistency,and other performance evaluations of portable particle spectrometers in scenarios such as indoor cigarette pollution,static and dynamic monitoring of outdoor atmospheric environment.The application testing mainly relies on the navigation monitoring platform of urban road environment to carry out dynamic measurement of particulate matter.Navigation monitoring research is mainly conducted in Tai’an and Jinan,Shandong Province,and takes Tai’an as an example to analyze the impact of air quality control policies on the particle size distribution of road environmental particles during the Winter Olympics;Taking Jinan as an example,analyze the impact of traffic factors such as speed and traffic flow on the particle size distribution of road environmental particles.The main research findings are as follows:(1)The performance and stability of the portable particle spectrometer SDS029 basically meet the needs of mobile monitoring of particle size spectra.The particle size calibration results show that the SDS029 has a low resolution for particles <1μm,but the overall error is within an acceptable range and the particle size identification is relatively accurate.The performance evaluation results of three scenarios,including indoor cigarette pollution,static monitoring of outdoor atmospheric environment and dynamic monitoring of road environment,show that the SDS029 responds to changes in ambient particulate concentration in a timely manner and is suitable for monitoring particulate concentration at different concentrations and in different scenarios.SDS029 underestimates the concentration of particles <1 μm and overestimates the concentration of particles 1-5 μm,leading it to underestimate the concentration of total particles(Particle Number,PN)by about 1/3.Although the SDS029 has a lower resolution for small particles compared to the reference device,its portability and low cost make it more suitable for grid-based monitoring.(2)During the Winter Olympics,the monitoring results of the navigation particle spectrometer in Tai’an showed that under non-dust weather days,the overall distribution of particle size in the road environment of Tai’an showed a bimodal pattern,with one peak near 4 μm and the other peak below 0.25 μm.The implementation scope and intensity of air pollution control measures in the Winter Olympics are different.During the Winter Olympics,the mass concentration of particulate matter during the control period decreased significantly compared with the pre-race stage,especially the concentration of particulate matter above 1 μm,mainly due to the effective control of road dust sources.The air pollution control measures in the pre-competition stage have less impact on the expressways within the main urban area of Tai’an than the main roads,secondary roads and branch roads.During the Winter Olympics,due to the comprehensive strengthening of control,the concentration of particulate matter in different types of roads decreased significantly compared with the pre-competition control stage.(3)The monitoring results of Jinan navigation particle spectrometer showed that the particle size distribution in Jinan was bimodal,with one peak at <0.25 μ m and the other around 4.5 μ m.The peak of the two peaks was close.In terms of spatial distribution,the concentration of particulate matter in the north and northeast of the main urban area of Jinan is higher than that in other areas.The results show that the particle size distribution of particulate matter in the road environment is related to traffic factors such as speed and traffic flow.Among them,the lower the road hardening rate,the higher the driving speed,the more serious the road dust,and the higher the concentration of coarse particulate matter.The greater the traffic flow of large oil vehicles and small oil vehicles,the greater the concentration of sub-micron particulate matter of 0.25-0.41 μm,while the new energy vehicles are correlated with the spatial distribution of coarse particulate matter of> 2.5 μm.