Sampsa Martikainen This email address is being protected from spambots. You need JavaScript enabled to view it.1, Sanna Saarikoski2, Paxton Juuti1, Hilkka Timonen2, Jorma Keskinen1, Panu Karjalainen1

1 Aerosol Physics Laboratory, Tampere University, Tampere, Finland
2 Atmospheric Composition Research, Finnish Meteorological Institute, Helsinki, Finland

Received: November 20, 2020
Revised: February 15, 2021
Accepted: February 16, 2021

 Copyright The Author's institutions. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are cited. 

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Martikainen, S., Saarikoski, S., Juuti, P., Timonen, H., Keskinen, J., Karjalainen, P. (2021). Soot Particle Agglomeration Inlet (SPAI) for Enabling Online Chemical Composition Measurement of Nanoparticles with the Aerosol Mass Spectrometer. Aerosol Air Qual. Res.


  • A concept for measuring nanoparticle chemical composition online.
  • Designed as an inlet to the Soot Particle Aerosol Mass Spectrometer (SP-AMS).
  • Laboratory tests with synthetic silver nanoparticles as test aerosol.
  • Up to 35-fold enhancement in the silver nanoparticle detection with the SP-AMS.


Nanoparticles are a subject of interest because of the effects they have on human health and climate. Chemical composition is one of the key properties that govern the mechanisms of these effects. However, current options for its measurement are very limited and they often require long collection times. The Soot Particle Aerosol Mass Spectrometer (SP-AMS) is an instrument designed for measuring the chemical composition of particles online. Due to losses in the sampling section of the instrument it has a lower particle size limit of 50 nm, preventing the analysis of nanoparticles. In this paper we present a measurement concept and a prototype system enabling the measurement of chemical composition of nanoparticles online. The studied nanoparticles are attached on the surfaces of artificially generated soot particles. We call this soot particle generation and agglomeration process Soot Particle Agglomeration Inlet (SPAI), which is designed as an inlet to the SP-AMS. We applied the prototype in laboratory tests, where the soot particle generation and the agglomeration section were characterized and optimized, and the performance of the SPAI was evaluated with silver nanoparticles as test aerosol. Applying the SPAI resulted in a 35-fold enhancement in the silver nanoparticle detection, compared to the measurement without it. The results indicate that the SPAI is a potential tool in resolving problems related to chemical composition measurement of nanoparticles, either as a standalone addition to the SP-AMS or combined with other sample pretreatment systems.

Keywords: Aerosol characterization, Nanoparticle, Chemical composition

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