Aerosol particle sizer

One type of point detector, the Aerosol Particle Sizer (APS), inhales air with a high-speed sampler, then counts and sizes the particulates. In the APS the counting and sizing of particles is done with a flow... 

Fig. 7 A Doppler-shift procedure for measuring the aerodynamic size of aerosol fine particles is used by the TSI aerosol particle sizer. (From...

A related technique that is suitable for measurement of aerosols at lower mass loadings is the aerodynamic particle sizer (3, 10). In this instrument the aerosol is rapidly accelerated through a small nozzle. Because of their inertia, particles of different aerodynamic sizes are accelerated to different velocities, and the smallest particles reach the highest speeds. The particle velocity is measured at the outlet of the nozzle. From the measurements of velocities of individual particles, particle size distributions can be determined. The instrument provides excellent size resolution for particles larger than about 0.8 xm in diameter, although sampling difficulties limit its usefulness above 10 xm. 

The most often measured property of the LRT wildfire smokes is the mass concentration of aerosol particles in fine (PM2.5) or submicron (PMi) or in fine and coarse size fraction together (PM10). The mass concentration is usually determined either with a tapered element oscillating microbalance (e.g., [19]), or with the instruments based on p-attenuation (e.g., [13]). In addition to mass concentration, real-time instruments can measure other physical properties of particles, e.g., number concentration of particles in different size fractions using a differential mobility particle sizer [13] or the optical characteristics of smoke by a nephelometer [32]. Ground-based instruments also include remote sensing instruments such as sun photometers [32],... 

Note DMS differential mobility spectrometer, SMPS scanning mobility particle sizer, CPC condensation particle counter, TDMPS twin differential mobility particle sizer, DMPS differential mobility particle sizer, OPC optical particle counter, APS aerodynamic particle sizer, MAS mass aerosol spectrometer, LAS-X optical laser aerosol spectrometer, ELPI electrical low pressure impactor... 

In addition to the TSP measurements some fractions of nanoparticle emissions in the range of 30 to 400 nm were done with Scaning Mobility Particle Sizer (SMPS), and particles in the range of 400 nm to 20 jim with an optical Aerosol Spectrometer. The sampling point in the dilution tunnel was close to the gas sample point. 

Mitchell JP, Nagel MW, Wiersema KJ, et al. Aerodynamic particle size analysis of aerosols from pressurized metered-dose inhalers comparison of Andersen 8-stage cascade impactor, next generation pharmaceutical impactor, and model 3321 aerodynamic particle sizer aerosol spectrometer. AAPS PharmSciTech 2003 4 E54. 

Aerosol size distribution determination A Differential Mobility Particle Sizer (DMPS) system comprising two (one short and one medium) Vienna-type Differential... 

Seifert, M., R. Tiede, M. Schnaiter, C. Linke, O. M6hler, U. Schurath and J. Strom Operation and performance of a differential mobility particle sizer and a TSl 3010 condensation particle counter at stratospheric temperatures and pressures, J. Aerosol Sci. 35 (2004) 981 -993. 

For a spherical particle of nonunit density the classical aerodynamic diameter is different from its physical diameter and it depends on its density. Aerosol instruments like the cascade impactor and aerodynamic particle sizer measure the classical aerodynamic diameter of atmospheric particles, which is in general different from the physical diameter of the particles even if they are spherical. 

One potential method for measuring the size of aerosol nanoparticles is a scanning mobility particle sizer (SMPS), consisting of a differential mobility analyzer (DMA) and a condensation particle counter (CPC). Aerosol particles enter the DMA where they are charged using a radioactive source and their size is classified based on the electrical mobility, Z, of the particles in the applied electrical field ... 

Van Gulijk, C., Marijnissen, J.C.M., Makkee, M., Moulijn, J.A. and Schmidt-Ott, A. (2004). Measuring diesel soot with a scanning mobility particle sizer and an electrical low-pressure impactor performance assessment with a model for liactal-fike agglomerates. J. Aerosol ScL, 35, 633-655. 

The condensation particle counter battery measurements are complemented by aerosol particle size distribution measurements using a dual differential mobility particle sizer system covering a size range of 3-900 nm, and an aerodynamic particle sizer covering aerosol particle sizes between 0.7 and 20 pm. In addition, air ions are detected using a balanced scanning mobility analyser and an air ion spectrometer. During the period of measurements, several new particle formation (nucleation) events occur in tropospheric air. 

Another aerosol spectrometer is manufactured by TSI Incorporated. Their instrument is known as the Aerodynamic Particle Sizer (APS). This system operates at subsonic flow conditions, and has a lower rate of count than the Aerosizer . The performance of the instrument has been documented in various publications [59, 60, 61]. In... 

R. C. Rodoff, S. V. Sankar, W. D. Bachalo, C. Sharky, Aerosol and Nebulizer Characterization Performance of a Phase Doppler Based Particle Sizer , presented in the European. Aerosol Conference Sept. 6-11 1992, Oxfr)rd United Kingdom. To contact Bachalo see reference 11. 

Setekleiv and Svendsen [180] used the same laser difliraction particle sizer to characterize the ability of mesh pads to separate droplets from the gas stream in a scrubber. Droplets in the size range 30-1000 p,m with a bi-modal distribution was obtained at low pressure. A rough sketch of the mounting of the laser diffraction instrument used in this work is shown in Fig. 13.17. Numerous applications of the LD particle sizer for solid particle size distribution measurements characterizing aerosols and suspensions can be found in the literature. Only a few examples of laser diffraction solid particle size distribution measurements relevant for fluidized bed system characterization are mentioned in this report. Garea et al. [71] measured the solid sorbent particle size distribution in a fluidized bed in-duct desulfurization reactor under in-duct conditions by laser diffraction. Ferrer et al. [66] studied fluidized bed combustion of refuse-derived fuel in presence of protective coal ash and measured the fly ash particle size distribution with a laser diffraction method. Tanneur et al. [192] measured the solid particle size distribution in a fluidized bed by use of a diffraction particle size analyzer. 

Aerosol Instrument Classification. Friedlander (34) classified the range of aerosol instrumentation in terms of resolution of particle size, time, and chemical composition. This classification scheme is illustrated in Figure 3. The ideal instrument would be a single-particle counter-sizer-analyzer. Operating perfectly, this mythical instrument would fully characterize the aerosol, with no lumping of size or composition classes, and would make such measurements sufficiently rapidly to follow any transients occurring in the aerosol system. 

Mobility sizers collect, count and determine size distributions for aerosols. These can typically handle particle sizes in the range of about 0.02-1 pm. An example is the differential mobility analyzer, which is described later in this section. 

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