Review of diesel particulate matter sampling - Department of ...

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Sulfuric Acid Particles 0.3 μm Hydrocarbon / Sulfate Particles 01/14/99 Page 10 Solid Carbonaceous / Ash Particles with Adsorbed Hydrocarbon / Sulfate Layer Figure 1. - Typical structure of engine exhaust particles (Kittelson, 1998a). Unburnt Oil 25% Sulfate and Water 14% Particle Composition For A Heavy-Duty Diesel Engine Tested in Heavy-Duty Transient Cycle Unburnt Fuel 7% Ash and Other 13% Carbon 41% Figure 2. - Particle composition for a heavy-duty diesel engine tested in a heavy-duty transient cycle (Kittelson, 1998a). [Composition varies widely with engine design.]
AEROSOL SIZE DISTRIBUTION Figure 3 shows the idealized diesel aerosol number and mass weighted size distributions (Kittelson, 1998a). The distributions are trimodal and lognormal in form. The concentration of particles in any size range is proportional to the area under the corresponding curve in that range. Most of the particle mass exists in the so-called accumulation mode in the 0.05 to 1.0 μm diameter range. This is where the carbonaceous agglomerates and associated adsorbed materials reside. The nuclei mode typically consists of particles in the 0.005 to 0.05 μm diameter range. This mode usually consists of volatile organic and sulfur compounds that form during exhaust dilution and cooling, and may also contain solid carbon and metal compounds. The nuclei mode typically contains 1-20 % of the particle mass and more than 90 % of the particle number. The coarse mode contains 5-20 % of the particle mass. It consists of accumulation mode particles that have been deposited on cylinder and exhaust system surfaces and later reentrained. Also shown in Figure 3 are definitions used to define atmospheric particles: PM10, D (diameter) < 10 μm; fine particles, D < 2.5 μm; ultrafine particles, D < 0.10 μm; and nanoparticles D < 0.05 μm or 50 nm. Definitions of ultrafine and nanoparticles are not universally agreed upon. Note that by number, nearly all of the particles emitted by a diesel engine (the same is true for a spark ignition engine) are nanoparticles. dlogDp 0.2 0.18 0.16 0.14 0.12 0.1 0.08 0.06 0.04 0.02 0 Nuclei Mode Nanoparticles Dp < 50 nm 0.001 0.010 0.100 1.000 10.000 Diameter (μm) Ultrafine Particles Dp < 100 nm 01/14/99 Page 11 Fractional deposition of particle with density of 1 g/cm 3 Accumulation Mode Fine Particles Dp < 2.5μm PM10 Dp < 10 μm Coarse Mode Mass Weighting Number Weighting Alveolar Deposition Fraction Figure 3. - Typical engine exhaust size distribution both mass and number weightings are shown (Kittelson, 1998a). For comparison, figure 4 shows the idealized atmospheric aerosol size distribution, which is also generally trimodal and lognormal in form (Whitby and Cantrell, 1975). The figure shows the mechanisms such as condensation and coagulation that transfer aerosol mass from one size 1 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0 Alveolar Deposition Fraction
Page 1 and 2: REVIEW OF DIESEL PARTICULATE MATTER
Page 3 and 4: ABSTRACT Federal government regulat
Page 5 and 6: INTRODUCTION Federal government reg
Page 7 and 8: • to critically evaluate methods
Page 9: Table 2. Changes in diesel engine t
Page 13 and 14: Figure 5. - Schematic illustrating
Page 15 and 16: Heat transfer during sampling and d
Page 17 and 18: • humidity and temperature • ba
Page 19 and 20: Doyle (1961) predicted that homogen
Page 21 and 22: Engine Emission Characteristics Eng
Page 23 and 24: accumulation mode particle diameter
Page 25 and 26: Adverse health effects of respirabl
Page 27 and 28: content of the particle. (Burtscher
Page 29 and 30: Table 7. Instrument summary Miscell
Page 31 and 32: Table 8. Studies Measuring Diesel A
Page 33 and 34: slowly moving diesel trucks, and a
Page 35 and 36: Figure 13. - Volume fraction versus
Page 37 and 38: Table 10. N/VT Ratios (Number of pa
Page 39 and 40: Figure 15. - Relationship between d
Page 41 and 42: Exhaust Constituents The nature of
Page 43 and 44: increased number concentrations of
Page 45 and 46: system, volatile particles evaporat
Page 47 and 48: With low carbon emission engines, t
Page 49 and 50: Kreso, et al. (1998a,b) looked at t
Page 51 and 52: • Treatment of sample dilution ai
Page 53 and 54: somewhat larger, 60 - 70 nm. The ma
Page 55 and 56: Bagley, S. T., et al. 1996. Charact
Page 57 and 58: Doyle, G.J. 1961. Self-Nucleation i
Page 59 and 60: Keady, P.B., F. R. Quant, and G. J.
Page 61 and 62:
Seminar on Particle Size Distributi
Page 63 and 64:
Watson, J. G. et al. 1998. Northern
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