Measuring soot particles from automotive exhaust emissions

Andres, Hanspeter; Lüönd, Felix; Schlatter, Jürg; Auderset, Kevin; Jordan-Gerkens, Anke; Nowak, Andreas; Ebert, Volker; Buhr, E.; Klein, Tobias; Tuch, Thomas; Wiedensohler, Alfred; Mamakos, Athanasios; Riccobono, Francesco; Discher, Kai; Högström, Richard; Yli-Ojanperä, Jaakko; Quincey, Paul

doi:10.1051/epjconf/20147700020

Cited by 3 publications

(3 citation statements)

References 3 publications

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“…At the same time, legislative limits were not met using soot aerosols for a CPC that was initially adjusted to meet the legislative targets with emery oil. The general influence of the calibration aerosol material (soot vs. emery oil) on counting efficiency was found to be in line with previous publications considering the experimental uncertainty [8,14,29,30].…”

Section: General Comparison Of the Soot Generatorssupporting

confidence: 90%

Calibration Uncertainty of 23nm Engine Exhaust Condensation Particle Counters with Soot Generators: a European Automotive Laboratory Comparison

Terres

Giechaskiel

Nowak

et al. 2021

Emiss. Control Sci. Technol.

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Calibration of condensation particle counters (CPC) to measure non-volatile particle number (PN) from vehicle emissions is a significant source of uncertainty of the regulated particle number measurements. In this work, the calibration uncertainty of automotive and calibration laboratories was determined in a first-of-its-kind comparison. For this purpose, the counting efficiency of a reference CPC for automotive exhaust emission measurements was determined at seven participants across Europe with ten soot aerosol generators. Calibration uncertainty was found to be very different in the CPC’s cut-off regime (around the D50 of 23nm) with a coefficient of variation (CoV) of 11% and the plateau regime (from the D90 of 41nm upwards) with a CoV of 4.5%. The uncertainty was higher for a group of soot generators with poorly optimized operating points with a CoV of 31% at 23nm and 5.8% at ≥41nm. Specific influence factors on the calibration uncertainty (measured as the inter-lab variability) could be identified. The calibration of the laboratories’ reference counters accounted for most of the variability in the plateau regime, while 20% of the variability was attributed to the sample flow measurement. Differences between soot generators were the main cause of variability in the cut-off regime due to the increased material sensitivity of the CPC at this particle size but had only secondary relevance in the plateau regime. The calibration uncertainty found in this inter-laboratory exercise should be a guideline for users and legislators, as it provides a typical value for the expected measurement uncertainty of a CPC for automotive exhaust PN.

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Section: General Comparison Of the Soot Generatorssupporting

confidence: 90%

Calibration Uncertainty of 23nm Engine Exhaust Condensation Particle Counters with Soot Generators: a European Automotive Laboratory Comparison

Terres

Giechaskiel

Nowak

et al. 2021

Emiss. Control Sci. Technol.

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“…Silver particles are typically small (< 20 nm) and can be assumed that they resemble more the metal oxides from the lubricant. Graphite particles have similarities with soot particles from combustion engines [22,23]. Furthermore, vehicle exhaust regulations require the measurement of the non-volatile (solid) particles, thus the silver and graphite particles of this study should be representative of the results expected with exhaust particles.…”

Section: Methodsmentioning

confidence: 98%

Assessment of two condensation particle counters (CPCs) in photometric mode for high concentration exhaust emission measurements

Giechaskiel¹,

Melas²,

Mamakos³

2023

Combustion Engines

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Condensation particle counters (CPCs) use light scattering to count particles after they have grown to micron size in a supersaturated environment. In single counting mode each particle is counted depending on whether the scattered light exceeds a threshold value or not. In photometric mode the total scattered light is converted in particle number concentration. While for laboratory grade particle number systems, CPCs are allowed to operate only in single counting mode, there is no such requirements for portable emissions measurements systems (PEMS) for real-driving emissions (RDE) testing or for instruments for periodic technical inspection (PTI) of vehicles. In this study two CPCs of the same model were assessed in single counting and photometric modes with silver and graphite particles with sizes ranging from 10 nm to 100 nm. The results showed that the concentration was measured accurately enough for particles in the 25 nm to 50 nm size range, but was underestimated and overestimated for smaller and larger particles, respectively. The key message is that the photometric mode should be avoided or calibrated in function of concentration and particle size.

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“…Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. shape is relevant in particular for security reasons concerning health care [1], food safety, environmental issues such as pollution [2], and alike. In 2018, Warheit provided an overview [3] of projects and activities to understand the potential hazards associated with exposure to new materials, whether in medical, cosmetic or industrial applications.…”

Section: Introductionmentioning

confidence: 99%

Traceable determination of the size of nanoparticles up to 500 nm by scanning electron microscopy in transmission mode based on simulation

Hüser

Bergmann

Klein

2023

Meas. Sci. Technol.

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The size measurement of nanoparticles contributes to the understanding of their properties and, thus, to the assessment of the risks they pose to health and the environment. For such measurements to be comparable and legally recognized, they must be traceable to the SI unit meter. Recently, interest in traceable measurements of polystyrene particles with sizes up to 500 nm has aroused, e.g. in the aerosol community. To meet this demand, we adapted an established method to traceably measure nanoparticles with high precision in the transmission mode of a scanning electron microscope (STEM-in-SEM or TSEM). Since this method was geared towards smaller particles, we adapted it at two points: New simulations with the program Geant4SEM allow a more accurate modelling, especially of the inelastical scattering processes. In addition, the image evaluation procedure was revised to account for the non-linear signal response at the particle boundary. The measured values obtained in this manner show good agreement with the values of two international intercomparisons.

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Measuring soot particles from automotive exhaust emissions

Cited by 3 publications

References 3 publications

Calibration Uncertainty of 23nm Engine Exhaust Condensation Particle Counters with Soot Generators: a European Automotive Laboratory Comparison

Calibration Uncertainty of 23nm Engine Exhaust Condensation Particle Counters with Soot Generators: a European Automotive Laboratory Comparison

Assessment of two condensation particle counters (CPCs) in photometric mode for high concentration exhaust emission measurements

Traceable determination of the size of nanoparticles up to 500 nm by scanning electron microscopy in transmission mode based on simulation

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