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

Richard Högström*, Jaakko Yli-Ojanperä, Antti Rostedt, Ilkka Iisakka, Jyrki M. Mäkelä, Martti Heinonen, Jorma Keskinen

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

13 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
JournalMetrologia
Volume48
Issue number5
DOIs
Publication statusPublished - 2011
MoE publication typeA1 Journal article-refereed

Keywords

  • aerosols
  • particles

Fingerprint

Dive into the research topics of 'Validating the single charged aerosol reference (SCAR) as a traceable particle number concentration standard for 10 nm to 500 nm aerosol particles'. Together they form a unique fingerprint.

Cite this