Validating the single charged aerosol reference (SCAR) as a traceable particle number concentration standard for 10 nm to 500 nm aerosol particles

Richard Högström (Corresponding Author), Jaakko Yli-Ojanperä, Antti Rostedt, Ilkka Iisakka, Jyrki M. Mäkelä, Martti Heinonen, Jorma Keskinen

Research output: Contribution to journalArticleScientificpeer-review

10 Citations (Scopus)

Abstract

Measurement of nanometre-sized aerosol particles is based on particle number concentration measurements. The commonly used method for providing traceability for these measurements involves charging and electrical counting of aerosol particles. This method requires that the particles are singly charged or that the average charge is exactly known, neither of which is easy to ensure. In the device called a single charged aerosol reference (SCAR), the fraction of multiply charged particles is minimal due to the novel operating principle of electrical charging and subsequent growth. In this study the SCAR was validated as a primary particle number concentration standard. The average charge of the output aerosol was evaluated for the whole operational particle size range. For this, the effect of the size distribution of the primary nanoaerosol and the output number concentration on the fraction of doubly charged and neutral particles was measured. It was found that the uncertainty caused by assuming singly charged particles is only 0.16%. A full uncertainty analysis was carried out for a condensation particle counter (CPC) calibration. According to the results, the relative expanded uncertainty of calibration was 3.0%. This represents a typical uncertainty level achieved in CPC calibrations performed with SCAR. As a result of this study, SCAR was validated as a particle number concentration standard suitable for traceable calibration of particle counting instruments in the particle size range from 10 nm to 500 nm.
Original languageEnglish
Pages (from-to)426-436
Number of pages11
JournalMetrologia
Volume48
Issue number5
DOIs
Publication statusPublished - 2011
MoE publication typeA1 Journal article-refereed

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Particles (particulate matter)
Aerosols
Calibration
Radiation counters
Charged particles
Condensation
Particle size
Uncertainty analysis
Uncertainty

Keywords

  • aerosols
  • particles

Cite this

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title = "Validating the single charged aerosol reference (SCAR) as a traceable particle number concentration standard for 10 nm to 500 nm aerosol particles",
abstract = "Measurement of nanometre-sized aerosol particles is based on particle number concentration measurements. The commonly used method for providing traceability for these measurements involves charging and electrical counting of aerosol particles. This method requires that the particles are singly charged or that the average charge is exactly known, neither of which is easy to ensure. In the device called a single charged aerosol reference (SCAR), the fraction of multiply charged particles is minimal due to the novel operating principle of electrical charging and subsequent growth. In this study the SCAR was validated as a primary particle number concentration standard. The average charge of the output aerosol was evaluated for the whole operational particle size range. For this, the effect of the size distribution of the primary nanoaerosol and the output number concentration on the fraction of doubly charged and neutral particles was measured. It was found that the uncertainty caused by assuming singly charged particles is only 0.16{\%}. A full uncertainty analysis was carried out for a condensation particle counter (CPC) calibration. According to the results, the relative expanded uncertainty of calibration was 3.0{\%}. This represents a typical uncertainty level achieved in CPC calibrations performed with SCAR. As a result of this study, SCAR was validated as a particle number concentration standard suitable for traceable calibration of particle counting instruments in the particle size range from 10 nm to 500 nm.",
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Validating the single charged aerosol reference (SCAR) as a traceable particle number concentration standard for 10 nm to 500 nm aerosol particles. / Högström, Richard (Corresponding Author); Yli-Ojanperä, Jaakko; Rostedt, Antti; Iisakka, Ilkka; Mäkelä, Jyrki M.; Heinonen, Martti; Keskinen, Jorma.

In: Metrologia, Vol. 48, No. 5, 2011, p. 426-436.

Research output: Contribution to journalArticleScientificpeer-review

TY - JOUR

T1 - Validating the single charged aerosol reference (SCAR) as a traceable particle number concentration standard for 10 nm to 500 nm aerosol particles

AU - Högström, Richard

AU - Yli-Ojanperä, Jaakko

AU - Rostedt, Antti

AU - Iisakka, Ilkka

AU - Mäkelä, Jyrki M.

AU - Heinonen, Martti

AU - Keskinen, Jorma

PY - 2011

Y1 - 2011

N2 - Measurement of nanometre-sized aerosol particles is based on particle number concentration measurements. The commonly used method for providing traceability for these measurements involves charging and electrical counting of aerosol particles. This method requires that the particles are singly charged or that the average charge is exactly known, neither of which is easy to ensure. In the device called a single charged aerosol reference (SCAR), the fraction of multiply charged particles is minimal due to the novel operating principle of electrical charging and subsequent growth. In this study the SCAR was validated as a primary particle number concentration standard. The average charge of the output aerosol was evaluated for the whole operational particle size range. For this, the effect of the size distribution of the primary nanoaerosol and the output number concentration on the fraction of doubly charged and neutral particles was measured. It was found that the uncertainty caused by assuming singly charged particles is only 0.16%. A full uncertainty analysis was carried out for a condensation particle counter (CPC) calibration. According to the results, the relative expanded uncertainty of calibration was 3.0%. This represents a typical uncertainty level achieved in CPC calibrations performed with SCAR. As a result of this study, SCAR was validated as a particle number concentration standard suitable for traceable calibration of particle counting instruments in the particle size range from 10 nm to 500 nm.

AB - Measurement of nanometre-sized aerosol particles is based on particle number concentration measurements. The commonly used method for providing traceability for these measurements involves charging and electrical counting of aerosol particles. This method requires that the particles are singly charged or that the average charge is exactly known, neither of which is easy to ensure. In the device called a single charged aerosol reference (SCAR), the fraction of multiply charged particles is minimal due to the novel operating principle of electrical charging and subsequent growth. In this study the SCAR was validated as a primary particle number concentration standard. The average charge of the output aerosol was evaluated for the whole operational particle size range. For this, the effect of the size distribution of the primary nanoaerosol and the output number concentration on the fraction of doubly charged and neutral particles was measured. It was found that the uncertainty caused by assuming singly charged particles is only 0.16%. A full uncertainty analysis was carried out for a condensation particle counter (CPC) calibration. According to the results, the relative expanded uncertainty of calibration was 3.0%. This represents a typical uncertainty level achieved in CPC calibrations performed with SCAR. As a result of this study, SCAR was validated as a particle number concentration standard suitable for traceable calibration of particle counting instruments in the particle size range from 10 nm to 500 nm.

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