Design Considerations and Performance Evaluation of a Compact Aerosol Particle Mass Analyzer

Abstract

A compact aerosol particle mass analyzer (APM) of which the size of the classifier was significantly reduced than that of the first commercial model (Kanomax Model 3600) was developed. Firstly, requirements for desired performance in classifying particle mass were set forth. Secondly, a theoretical framework for the design parameters of an APM that satisfies the requirements was formulated. Thirdly, the design parameters were determined that satisfies the requirements while reducing the instrument size. The requirements include the condition that the classification range covers from 0.001 to 1000 fg (approximately 12 to 1200 nm in size for spherical particles having the density of 1 g/cm 3 ), and the condition that both the classification resolution and particle penetration in this mass range are higher than certain specified values. A prototype having the design parameters determined according to this theoretical framework was constructed, and its performance was evaluated experimentally. The external dimensions of the electrodes of the compact APM are approximately 140 mm in length and 60 mm in diameter. It was confirmed that the performance of the compact APM operated at the aerosol flow rate of 0.3 L/min was comparable to that of the Model 3600 APM operated at 1 L/min. Because of the reduced size and of the resultant improved portability, it is expected that the compact APM is readily applicable to field measurements.

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

“…Applying Equations (6) and (8) yields that λ C can vary from 0.47 to 2.30. Figure 3 shows the operational diagram of nano-PMC, similar to those introduced by Tajima et al (2011Tajima et al ( , 2013. The dashed distorted parallelogram represents the operational window of nano-PMC in the v ¡ M C space.…”

“…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.…”

“…A flow rate of Q D 0.3 L/min offers a much wider range of resolvable masses. Table 2 summarizes operational constraints and resolvable particle-mass range of nano-PMC for two different volumetric flow rates studied in comparison with those of the commercially available Kanomax APM-3600 (Ehara et al 1996;Tajima et al 2011), the compact APM (Tajima et al 2013), and the Cambustion CPMA (Olfert and Collings 2005). Because of the higher rotational speed that can be achieved by nano-PMC, the instrument exhibits a lower detectable mass limit that is one order of magnitude smaller compared with those of other devices at a flow rate of 0.3 L/min, and one order of magnitude larger at 1.5 L/min.…”

“…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:…”

“…The first design was adopted by Olfert and Collings (2005) and Olfert et al (2006), resulting in the commercially available PMC known as the centrifugal particle mass analyzer (Cambustion CPMA). More recently, Tajima et al (2013) developed a miniaturized version of classical APM design, referred to as the "compact APM. "…”