Size Distributions of Motor Vehicle Exhaust PM: A Comparison Between ELPI and SMPS Measurements

Maricq, M. Matti; Podsiadlik, Diane H.; Chase, Richard E.

doi:10.1080/027868200416231

Cited by 177 publications

(105 citation statements)

References 17 publications

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“…Note that truncation of the currents, or derived concentrations, to eliminate negative values can significantly exacerbate the artifact. These negative currents are necessary to cancel the positive currents induced on the upper stages by small particles that pass through the stage without impacting (Maricq et al 2000).…”

Section: #1-coarse Mode Artifactmentioning

confidence: 99%

Measuring Particulate Mass Emissions with the Electrical Low Pressure Impactor

Maricq

Chase

2006

Aerosol Science and Technology

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The electrical low pressure impactor (ELPI) is a useful tool for recording transient particle size distributions, such as in motor vehicle emissions. But for sub-micron aerosols, the straightforward mass weighting and integration of these size distributions overestimates the particulate matter (PM) mass by a factor of two or more. The present article examines the sources of this discrepancy and develops an analysis that allows quantitative PM mass measurement with an accuracy of about 20%. This procedure is applied to measure motor vehicle PM emissions, and the results are compared with filter-based gravimetric determinations. Good agreement is achieved for diesel and direct injection gasoline vehicles. For particulate trap equipped diesel vehicles and conventional gasoline vehicles, the PM mass recorded by the ELPI is often substantially lower than the filter based mass owing to the gaseous adsorption artifact of the latter. Accurate work at very low emissions levels, less than ∼1 mg/mi, requires further study of how reliably the ELPI can provide semivolatile nanoparticle mass as well as an improved understanding of filter-based vehicle exhaust measurement.

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Section: #1-coarse Mode Artifactmentioning

confidence: 99%

Measuring Particulate Mass Emissions with the Electrical Low Pressure Impactor

Maricq

Chase

2006

Aerosol Science and Technology

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“…The most common used in the case of vehicle exhaust gas are the Electrical Low Pressure Impactor (ELPI, Keskinen et al 1992;Khalek 2000;Maricq et al 2000;Witze et al 2004;Zervas et al 2004;Zervas et al 2005 …”

Section: Introductionmentioning

confidence: 99%

Comparison of Exhaust Particle Number Measured by EEPS, CPC, and ELPI

Zervas

Dorlhène

2006

Aerosol Science and Technology

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An Engine Exhaust Particle Sizer (EEPS) Spectrometer, a Condensation Particle Counter (CPC) and an Electrical Low Pressure Impactor (ELPI) were used to determine the exhaust particle number of a Diesel engine on steady speeds and on the New European Driving Cycle (NEDC), upstream and downstream several Diesel Particulate Filters (DPF). In order to obtain different particle numbers, five DPFs with different porosity were used. The above three instruments give quite similar total particle numbers on steady speeds and on the NEDC for the tests upstream DPF. Downstream DPF, EEPS reaches its limit of measurement; however, the total particle numbers obtained by this instrument are still close to the particle numbers obtained by CPC and ELPI. The particle number versus time of the three instruments are quite close in the case of the NEDC measurements upstream DPF. Downstream DPF, CPC, and ELPI give quite similar signals, but EEPS reached its limits of detection. Upstream DPF, ELPI, and EEPS determine quite similar median diameters in the case of steady speeds, despite their different shape in particle size distribution. INTRODUCTIONCurrent European regulations are based on a gravimetric method for the exhaust PM measurements; however, other techniques will probably be necessary in the future. The measurement of particle number instead of particulate mass is proposed for future regulations (UNECE 2001).Many methods can determine the exhaust particle number and/or size determination. The most common used in the case of vehicle exhaust gas are the Electrical Low Pressure Impactor (ELPI, Keskinen et al. 1992;Khalek 2000;Maricq et al. 2000;Witze et al. 2004;Zervas et al. 2004;Zervas et al. 2005

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“…Note that the APS measures the aerodynamic diameter whereas the SMPS measures the electrical mobility diameter. The SMPS can measure particle size distributions with high resolution in a nanometer range in comparison to other instruments such as an electrical low pressure impactor (ELPI) (Maricq et al, 2010). Besides, the particle size distributions of the ambient aerosols measured using the SMPS and ELPI exhibited similar features even though the aerodynamic diameter was essentially different from the electrical mobility diameter by a factor of the square root of the particle density (ρ 1/2 ) (Shi et al, 1999).…”

Section: Evaluation Of the Separation Characteristics Of Particles Fomentioning

confidence: 71%

Development of a High-Volume PM2.5 Particle Sampler Using Impactor and Cyclone Techniques

Okuda

Isobe

Nagai

et al. 2015

Aerosol Air Qual. Res.

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Detailed mechanisms of the cellular biochemical reactions associated with the toxicity of PM 2.5 have not been elucidated well so far, because it is difficult to collect a sufficient amount of PM 2.5 particles to carry out toxicity assays using cells. A high-volume PM 2.5 particle sampler using the impactor and cyclone techniques has been developed in this study. The 50% cut-points of the impactor and cyclone for ambient aerosols at 1,100 L/min of air flow were 2.0 μm and 0.15-0.18 μm, respectively. The separation characteristics of the impactor were similar to those of the WINS impactor. The contents of EC, which is an aggregate/agglomerate of primary particles with sizes less than 100 nm, in the cyclone particles was similar to that in the filter particles. The contents of organic matter and ammonium in the particles collected using the cyclone system were lower than those in the particles collected using traditional filter sampling. We propose that the highvolume PM 2.5 particle sampler developed in this study can collect a large amount of aerosol particles in a "powder form" and can also avoid certain sampling artifacts caused by the adsorption of volatile organic compounds and gaseous ammonia to particles on the filter media. The sampling device developed in this study allows researchers to collect a sufficient amount of PM 2.5 particles for cell exposure studies without the use of filters.

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Size Distributions of Motor Vehicle Exhaust PM: A Comparison Between ELPI and SMPS Measurements

Cited by 177 publications

References 17 publications

Measuring Particulate Mass Emissions with the Electrical Low Pressure Impactor

Measuring Particulate Mass Emissions with the Electrical Low Pressure Impactor

Comparison of Exhaust Particle Number Measured by EEPS, CPC, and ELPI

Development of a High-Volume PM2.5 Particle Sampler Using Impactor and Cyclone Techniques

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