Mass size distribution

Using the above concepts, models have been developed to predict size distribution from comminution devices. An assumption is that the rate of breakage of material of a particular size is proportional to the mass of that size present in the comminution zone of a machine. If the mass size distribution in the machine is where is the mass of particles in size class /, then rate of breakage is given by equation 2. 

Figure 9.35 shows a typical set of mass size distributions for total suspended particles (TSP), Na, Cl, Al, V, NO-, S04, and NH4 at Chichi in the Ogasawara (Bonin) Islands, about 1000 km southeast of the main island of Japan (Yoshizumi and Asakuno, 1986). As expected for a marine site such as this, Na and Cl from sea salt predominate, and both the TSP and Na and Cl components peak in the coarse particle range. Al is also found primarily in the larger particles and is attributed to a contribution from soil dust. On the other hand, vanadium, non-sea salt sulfate (nss-S04 ), and ammonium are primarily in the fine particles. The vanadium levels are extremely low and likely reflect long-range transport of an air mass containing the products of combustion of fuel oil, which contains V because it is likely associated with a combustion source, it would be expected in the fine particle mode, consistent with Fig. 9.35. 

Rivera-Carpio, C. A., C. E. Corrigan, T. Novakov, J. E. Penner, C. F. Rogers, and J. C. Chow, Derivation of Contributions of Sulfate and Carbonaceous Aerosols to Cloud Condensation Nuclei from Mass Size Distributions, . /. Geophys. Res., 101, 19483-19493 (1996). 

Novakov and Penner (1993) measured the mass size distributions of sulfur, organic carbon, and chlorine (characteristic of sea salt) as well as the CCN concentration (at 0.5% supersaturation), nss, and Aitken nuclei concentrations at a mountain peak in Puerto Rico. 

Sillanpaa M, Saarikoski S, Hillamo R, Pennanen A, Makkonen U, Spolnik Z, Van Grieken R, Koskentalo T, Salonen RO (2005) Chemical composition, mass size distribution and source analysis of long-range transported wildfire smokes in Helsinki. Sci Total Environ 350 119-135... 

Frey AK, Tissari J, Saarnio KM, Timonen HJ, Tolonen-Kivimaki O, Aurela MA, Saarikoski SK, Makkonen U, Hytonen K, Jokiniemi J, Salonen RO, Hillamo REJ (2009) Chemical composition and mass size distribution of fine particulate matter emitted by a small masonry heater. Boreal Environ Res 14 255-271... 

Longley ID, Gallagher MW, Dorsey JR, Flynn M, Allan JD, Alfarra D, Inglish D (2003) A case study of aerosol (4.6 nm < Dp < 10 pm) number and mass size distribution measurements in a busy street canyon in Manchester, UK. Atmos Environ 37 1563-1571... 

Most of the studies on size-resolved aerosol mass concentrations in areas with different levels of pollution show that particulate matter typically exhibit a bimodal distribution, with most of their mass being found in the submicron size range (dae < 1pm) and an additional minor mode in the coarse fraction (1 < dae < 10 pm) (Maenhaut et al., 2002 Smolfk et al., 2003 Wang et al., 2003 Gajananda et al., 2005 Samara and Voutsa, 2005). However, with instrumentation allowing more precise measurements, the aerosol mass size distribution was found to be multimodal with the preponderance of a fine mode (dae < 0.2 pm) and an accumulation mode (dae 0.5pm), with a minor coarse mode at d 3-4pm (Raes et al., 2000 Pillai and Moorthy, 2001 Berner et al., 2004). Traditionally, atmospheric researchers classify airborne particles into three size classes coarse (2.5 < c/ ie < 10pm), fine... 

Figure 12.1. Theoretical aerosol mass size distribution profile showing a typical segmentation of chemical species into fine (dae < 2.5 pm) and coarse (2.5 < dae < 10 pm) modes. [Adapted from Seinfeld (1986), Seinfeld and Pandis (1998), Krivdcsy and Molnar (1998), and Samara and Voutsa (2005).]...

Berner, A., Galambos, Z., Ctyroky, P, Fruhauf, P., Hitzenberger, R., Gomiscek, B., Hauck, H., Preining, O., and Puxbaum, H. (2004). On the correlation of atmospheric aerosol components of mass size distributions in the larger region of a central European city. Atmos. Environ. 38, 3959-3970. 

Maenhaut, W., Cafmeyer, J., Dubtsov, S., and Chi, X. (2002). Detailed mass size distribution of elements and species, and aerosol mass closure during fall 1999 at Gent, Belgium. Nucl. Instr. Meth. Phys. Res. B 189,238-242. 

Pillai, P. S., and Moorthy, K. K. (2001). Aerosol mass-size distributions at a tropical coastal environmentresponse to mesoscale and synoptic processes. Atmos. Environ. 35, 4099-4112. 

The mass median aerodynamic diameter (MMAD) is defined as the aerodynamic diameter which divides the aerosol mass size distribution in half. 

I. Salma, I. Balashazy, R. Winkler-Heil, W. Hofmann, Gy. Zaray, Effect of particle mass size distribution on the deposition of aerosols in the human respiratory system,... 

Dividing the adsorbate size distribution by the mass size distribution gives an adsorbate concentration (i.e., the amount adsorbed per mass of particles) distribution as outlined previously. Figure 2b shows that the smaller particles contain the highest pollution content. This is consistent with the concept that smaller particles have a higher specific surface area, but changes in geochemistry of the particle with size could also be involved. 

Physical aspects of particles (number or mass size distribution, density and shape). 

Fig. 7-20. Mass-size distribution (A log r = 0.303) of individual anions and cations associated with the rural continental aerosol at Deuselbach, West Germany (nequiv/m3, = nmol/m3 times the ionic charge number). Left Individual contributions. Right Balance between cations and anions. A cation deficit must be balanced by protons leading to a corresponding acidity. [Data from Mehlmann (1986).]...

Rahn (1975) has summarized data for many highly enriched elements. From a limited number of elemental mass-size distributions, Rahn (1975a)... 

Fig. 8-7. Washout coefficients according to Slinn and Hales (1971) are shown in curves A and B (left-hand scale). They are based on rain drop size spectra of Zimin (1964) with r,max = 0.2 and 1 mm, respectively, and a precipitation rate of 10 mm/h (10 kg/m2 h). Curve C represents the first term and curves D and E the second term in the bracket of Eq. (8-6) in nonintegrated form (right-hand scale applies). These latter three curves are based on the mass-size distribution for the rural continental aerosol in Fig. 7-3. Curve C was calculated with eA(r2)=l for r2>0.5 ra and eA < I for r2<0.5(im, decreasing linearly toward zero at r2 = 0.06 p.m. This leads to eA = 0.8. Curves D and E were obtained by using the washout coefficients of curves A and B, respectively. Note that below-cloud scavenging (curves D and E) affect only giant particles, whereas nucleation scavenging (curve C) incorporates also submicrometer particles.

Atmospheric particles occur in a wide range of sizes. The size distribution can be expressed as a number-, surface-, or mass-density function. If the mass-size distribution is presented differentially versus the logarithm of the particle size (dM/dlg AD vs. Ig AD M, particle mass AD, aerody-... 

Berner A (1978) A five stage cascade impactorfor measurement of mass-size distributions of aerosols (in German). Chem Ing Tech 50 399. 

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