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

More documents

Recommendations

Info

Table 7. Instrument summary Instrument Parameter Range Comments Inertial mobility instuments (cascade impactors) Micro-orifice Aerodynamic 0.056 - 10 um * Not real-time, gravimetric and chemical uniform deposit diameter analysis performed after collection. impactor (MOUDI) Nano- MOUDI Aerodynamic 0.010 - 18 um * Same as MOUDI diameter evaporate. 01/14/99 Page 28 * Low pressure may cause volatile particles Electrical low Aerodynamic 0.030 - 10 um * Near realtime with time resolution from 2 - 15 s. pressure impactor diameter * Can measure ambient concentrations, but low (ELPI) pressure may cause volatile particles to evaporate. Electrical mobility instruments Electrical aerosol Electrical Mobility 0.003 - 1 um * Time resolution between 2-3 min, 11 size intervals. analyzer Equivalent * Strongly distorted results if concentration and size Diameter change during scan. * More sensitive to these changes than SMPS. * Requires high dilution (> 200:1) to prevent electrometer saturation. * Results for diameters < 10 nm are questionable unless number concentrations are high, due to diffusional losses. * Pre-classification stage must be used to remove particles larger than 1.0 um for diesel aerosol measurements Differential mobility Electrical Mobility 0.01 - 0.5 um * Discrete changes in electric field of DMPS makes particle sizer Equivalent sampling for entire range slower than for SMPS. (DMPS) Diameter * Biased results if concentration and size change during scan. * Pre-classification stage must be used to remove particles larger than 1.0 um for diesel aerosol measurements Scanning mobility Electrical Mobility 0.010 - 0.7 um * 2 - 4 min scan time for 100 size intervals - can ramp particle sizer Equivalent DMA electric field to reduce scan time. (SMPS) Diameter * Time resolution of a few seconds for a single channel. * Scan times as short as 30 s may be used with lost resolution * Biased results if concentration and size change during scan. * Pre-classification stage must be used to remove particles larger than 1.0 um for diesel aerosol measurements nano-Differential Electrical Mobility 3 - 50 nm * Time resolution of about 10 s required to scan mobility analyzer Equivalent all intervals. (nano-DMA) Diameter * Not fully characterized and developed
Table 7. Instrument summary Miscellaneous instruments Photoelectric aerosol Surface area - < 1 um * Material condensing on particle surface can sensor (PAS) senses PAH bound lower limit not interfer with measurement. to carbon surface * Does not measure particle size 01/14/99 Page 29 * Response time < 1 s reported * Particles > 1 um are not charged efficiently. Aerosol time-of-flight Aerodynamic 0.3 - 50 um * Real-time measurement of up to 600 part./min. mass spectrometer diameter and (ATOFMS) chemical composition Epiphaniometer Fuchs surface < 7.0 um * Time resolution is between 5 - 30 min depending area upon the analysis code used. * For particles between 0.10 - 3 um the instrument must be calibrated to determine response. Diffusion battery Diffusion 0.01 - 0.5 um * Slow sampling time requires steady-state Aerodynamic Sizing Miscellaneous mobililty conditions. nano-SMPS EAA SMPS nano-MOUDI (manual) * Strongly distorted results if concentration and size change during scan. Particle Sizing Instruments MOUDI (manual) ELPI ATOFMS 1 10 100 1000 10000 100000 Sizing Range (nm) Electrical Mobility Sizing Figure 10. - Dynamic range of particle sizing instruments EVALUATION OF ROADWAY, TUNNEL, AND OCCUPATIONAL TEST METHODS A number of studies have determined the size distribution of diesel aerosol in different environments such as mines, tunnels, roadways and ambient atmosphere. In most cases these studies have evaluated a mixed combustion aerosol consisting of emissions from both gas and diesel fueled vehicles. In some cases the investigators determined the mass, number and
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 and 10: Table 2. Changes in diesel engine t
Page 11 and 12: AEROSOL SIZE DISTRIBUTION Figure 3
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: content of the particle. (Burtscher
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

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

Create successful ePaper yourself

Delete template?

Save as template?