Performance Verification Of The Novel Cascade Impactor & Sampling And Analyzing On Aerosols

Aerosols affect greatly the environment pollution, climate changes andhuman health. The study of aerosols sampling and analyzing is an importantobject in the atmospheric environment research fields. Aerosols samplingdevices based on the theory of inertia impaction have been widely appliednowadays. The novel cascade impactor (NCI), which possesses nationalintellectual property, has the function of collecting aerosols according to thediameter of particles, that is, NCI can accomplish the sampling of 38~10,10~5.0,5.0~2.5,2.5~1.0,1.0~0.5,0.5~0.25,0.25~0.1μm at the same time.The flat samples obtained with enough different particles are propitious to thephysical and chemical analysis subsequently. The thesis focuses mainly on theperformance verification of NCI, sampling and analyzing of aerosol particles.It has been discussed the operating principles and structure, calculating anddesigning methods of each inlet nozzle of NCI on the basis of elaboratingtheories of aerodynamics, the concepts and the harm of aerosols and the newdeveloping trend of aerosols research. According to the worldwide technicalrequirements of related cascade impactor, the technique function of NCI isverified by the uniform and monodisperse particles of 1.5~17μm. Comparingwith Andersen eight-stage inertial impactor, the results show that NCI canrealize the technical requirements of collecting aerosol according to diameterof particles.As the requirements of "863 High-tech", aerosol particles have beensampled in three typical cities, Chongqing, Ningbo and Beijing, by two novelcascade impactors that have the same air flow rate of 10 l / min. Concentrationof quality and quantity on aerosol particles have been respectively calculatedand analyzed during the sampling period. Approximate distributions ofaerosol particles of three cities are presented by comparison with local indexof air pollution given by national environment department.The chemical composition of aerosol particles in these three cities hasbeen analyzed by SEM and EDX. The regional distinctions of aerosol particleshave been presented. After aerosol samples in these three cities have beenanalyzed by morphology analysis, superficial positive and negative ionspectrum and depth profile analysis using TOF — SIMS, compositiondifference of local aerosol particles during different time has been given.Furthermore, all above information can provide reliable supports for theresearch of aerosol particles.