Mass Range and Optimized Operation of the Aerosol Particle Mass Analyzer

Abstract

We investigated, theoretically, the mass range in which an aerosol particle mass analyzer (APM) can be used for classification, and how the APM classification performance can be optimized. We listed factors that set limits to the APM, which were constraints of the rotation speed and the voltage, as well as requirements on the APM classification performance parameter, λ, that guarantee at least minimal performance in both resolution and penetration. We introduced the APM operation diagram, which is a tool to visualize the limits and mass range. We proposed to operate the APM that was considered in this study with the λ value set within the range from 0.25 to 0.5 for optimum classification performance by balancing both resolution and penetration. The mass range for the APM, with the λ value maintained between 0.25 and 0.5, was calculated to be from 0.003 to 2000 fg, which corresponds to the diameter range from 20 to 1600 nm for the density of 1 g/cm 3 . To verify the validity of the mass range and the idea of the optimized operation, we carried out experiments on an APM with polystyrene and sodium-chloride particles that were classified by electrical mobility. We found that the APM was able to provide bell-shaped spectra down to 12 nm, and was able to perform mass classification with an accuracy better than 5% down to 50 nm. Underestimation of mass and reduction of resolution and penetration were observed at sizes smaller than about 30 nm.

Characterization of a Three Wavelength Photoacoustic Soot Spectrometer (PASS-3) and a Photoacoustic Extinctiometer (PAX)

“…1a). The ratio of the sample and sheath flows of the DMA remained constant at a value of 0.10, and the λ parameter, which characterizes the classification performance of the APM (Tajima et al 2011), was maintained at either 0.32 or 0.50.…”

Demonstration of the CPMA-Electrometer System for Calibrating Black Carbon Particulate Mass Instruments

“…Then the sample was split between the aerosol electrometer (4 L/min) and the challenge instrument (2 L/min for the LII 300, or 4 L/min for the MSS), allowing both instruments to measure the same mass 1 More information about determining resolution can be found in Tajima et al (2011), which discusses the resolution of the aerosol particle mass analyser (APM). The APM operates very similarly to the CPMA, and the way that the resolution is defined and determined is directly comparable.…”

The Nano-Particle Mass Classifier (Nano-PMC): Development, Characterization, and Application for Determining the Mass, Apparent Density, and Shape of Particles with Masses Down to the Zeptogram Range

“…The nano-PMC uses the same operating principle and a similar geometry as the APM models described by Ehara et al (1996) and Tajima et al (2011Tajima et al ( , 2013. The equations of particle motion within the classification region of nano-PMC can FIG.…”

“…Particles at radial positions other than r C experience force imbalance and therefore travel toward the classifier walls. This effectively lowers the maximum amplitude P of the transfer function, which can be estimated by (Tajima et al 2011(Tajima et al , 2013:…”

“…Response of Nano-PMC The response of the classifier, expressed as the particle number concentration N (cm ¡3 ) at its outlet when charged aerosol particles are passed through, is given by the convolution of mass distribution of aerosol at its inlet n M ð ÞD dM=dN with the transfer function of the classifier V nano ¡ PMC M ð Þ (Tajima et al 2011):…”