A new high transmission inlet for the Caltech nano-RDMA for size distribution measurements of sub-3 nm ions at ambient concentrations

Alessandro Franchin, Andrew J. Downard, Juha Kangasluoma, Tuomo Nieminen, Katrianne Lehtipalo, Gerhard Steiner, Hanna E. Manninen, Tuukka Petäjä, Richard C. Flagan, Markku Kulmala

Research output: Contribution to journalArticleScientificpeer-review

Abstract

Reliable and reproducible measurements of atmospheric aerosol particle number size distributions below 10 nm require optimized classification instruments with high particle transmission efficiency. Almost all DMAs have an unfavorable potential gradient at the outlet (e.g. long column, Vienna type) or at the inlet (nano-radial DMA). This feature prevents them from achieving a good transmission efficiency for the smallest nanoparticles. We developed a new high transmission inlet for the Caltech nano-radial DMA (nRDMA) that increases the transmission efficiency to 12 % for ions as small as 1.3 nm in mobility equivalent diameter (corresponding to 1.2×10^-4 m^2V^-1s^-1 in electrical mobility). We successfully deployed the nRDMA, equipped with the new inlet, in chamber measurements, using a Particle Size Magnifier (PSM) and a booster Condensation Particle Counter (CPC) as a counter. With this setup, we were able to measure size distributions of ions between 1.3 and 6 nm, corresponding to a mobility range from 1.2×10^-4 to 5.8×10^-6m^2V^-1s^-1. The system was modeled, tested in the laboratory and used to measure negative ions at ambient concentrations in the CLOUD 7 measurement campaign at CERN. We achieved a higher size resolution than techniques currently used in field measurements, and maintained a good transmission efficiency at moderate inlet and sheath air flows (2.5 and 30 LPM, respectively). In this paper, by measuring size distribution at high size resolution down to 1.3 nm, we extend the limit of the current technology. The current setup is limited to ion measurements. However, 20 we envision that future research focused on the charging mechanisms could extend the technique to measure neutral aerosol particles as well, so that it will be possible to measure size distributions of ambient aerosols from 1 nm to 1 μm.
Original languageEnglish
JournalAtmospheric Measurement Techniques Discussions
Volume8
Pages (from-to)5847–5876
Number of pages30
ISSN1867-8610
DOIs
Publication statusPublished - 15 Jun 2015
MoE publication typeA1 Journal article-refereed

Fields of Science

  • 114 Physical sciences
  • ATMOSPHERIC AEROSOL-PARTICLES

Cite this

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title = "A new high transmission inlet for the Caltech nano-RDMA for size distribution measurements of sub-3 nm ions at ambient concentrations",
abstract = "Reliable and reproducible measurements of atmospheric aerosol particle number size distributions below 10 nm require optimized classification instruments with high particle transmission efficiency. Almost all DMAs have an unfavorable potential gradient at the outlet (e.g. long column, Vienna type) or at the inlet (nano-radial DMA). This feature prevents them from achieving a good transmission efficiency for the smallest nanoparticles. We developed a new high transmission inlet for the Caltech nano-radial DMA (nRDMA) that increases the transmission efficiency to 12 {\%} for ions as small as 1.3 nm in mobility equivalent diameter (corresponding to 1.2×10^-4 m^2V^-1s^-1 in electrical mobility). We successfully deployed the nRDMA, equipped with the new inlet, in chamber measurements, using a Particle Size Magnifier (PSM) and a booster Condensation Particle Counter (CPC) as a counter. With this setup, we were able to measure size distributions of ions between 1.3 and 6 nm, corresponding to a mobility range from 1.2×10^-4 to 5.8×10^-6m^2V^-1s^-1. The system was modeled, tested in the laboratory and used to measure negative ions at ambient concentrations in the CLOUD 7 measurement campaign at CERN. We achieved a higher size resolution than techniques currently used in field measurements, and maintained a good transmission efficiency at moderate inlet and sheath air flows (2.5 and 30 LPM, respectively). In this paper, by measuring size distribution at high size resolution down to 1.3 nm, we extend the limit of the current technology. The current setup is limited to ion measurements. However, 20 we envision that future research focused on the charging mechanisms could extend the technique to measure neutral aerosol particles as well, so that it will be possible to measure size distributions of ambient aerosols from 1 nm to 1 μm.",
keywords = "114 Physical sciences, ATMOSPHERIC AEROSOL-PARTICLES",
author = "Alessandro Franchin and Downard, {Andrew J.} and Juha Kangasluoma and Tuomo Nieminen and Katrianne Lehtipalo and Gerhard Steiner and Manninen, {Hanna E.} and Tuukka Pet{\"a}j{\"a} and Flagan, {Richard C.} and Markku Kulmala",
year = "2015",
month = "6",
day = "15",
doi = "10.5194/amtd-8-5847-2015",
language = "English",
volume = "8",
pages = "5847–5876",
journal = "Atmospheric Measurement Techniques Discussions",
issn = "1867-8610",
publisher = "Copernicus GMBH",

}

A new high transmission inlet for the Caltech nano-RDMA for size distribution measurements of sub-3 nm ions at ambient concentrations. / Franchin, Alessandro; Downard, Andrew J.; Kangasluoma, Juha; Nieminen, Tuomo; Lehtipalo, Katrianne; Steiner, Gerhard; Manninen, Hanna E.; Petäjä, Tuukka; Flagan, Richard C.; Kulmala, Markku.

In: Atmospheric Measurement Techniques Discussions, Vol. 8, 15.06.2015, p. 5847–5876.

Research output: Contribution to journalArticleScientificpeer-review

TY - JOUR

T1 - A new high transmission inlet for the Caltech nano-RDMA for size distribution measurements of sub-3 nm ions at ambient concentrations

AU - Franchin, Alessandro

AU - Downard, Andrew J.

AU - Kangasluoma, Juha

AU - Nieminen, Tuomo

AU - Lehtipalo, Katrianne

AU - Steiner, Gerhard

AU - Manninen, Hanna E.

AU - Petäjä, Tuukka

AU - Flagan, Richard C.

AU - Kulmala, Markku

PY - 2015/6/15

Y1 - 2015/6/15

N2 - Reliable and reproducible measurements of atmospheric aerosol particle number size distributions below 10 nm require optimized classification instruments with high particle transmission efficiency. Almost all DMAs have an unfavorable potential gradient at the outlet (e.g. long column, Vienna type) or at the inlet (nano-radial DMA). This feature prevents them from achieving a good transmission efficiency for the smallest nanoparticles. We developed a new high transmission inlet for the Caltech nano-radial DMA (nRDMA) that increases the transmission efficiency to 12 % for ions as small as 1.3 nm in mobility equivalent diameter (corresponding to 1.2×10^-4 m^2V^-1s^-1 in electrical mobility). We successfully deployed the nRDMA, equipped with the new inlet, in chamber measurements, using a Particle Size Magnifier (PSM) and a booster Condensation Particle Counter (CPC) as a counter. With this setup, we were able to measure size distributions of ions between 1.3 and 6 nm, corresponding to a mobility range from 1.2×10^-4 to 5.8×10^-6m^2V^-1s^-1. The system was modeled, tested in the laboratory and used to measure negative ions at ambient concentrations in the CLOUD 7 measurement campaign at CERN. We achieved a higher size resolution than techniques currently used in field measurements, and maintained a good transmission efficiency at moderate inlet and sheath air flows (2.5 and 30 LPM, respectively). In this paper, by measuring size distribution at high size resolution down to 1.3 nm, we extend the limit of the current technology. The current setup is limited to ion measurements. However, 20 we envision that future research focused on the charging mechanisms could extend the technique to measure neutral aerosol particles as well, so that it will be possible to measure size distributions of ambient aerosols from 1 nm to 1 μm.

AB - Reliable and reproducible measurements of atmospheric aerosol particle number size distributions below 10 nm require optimized classification instruments with high particle transmission efficiency. Almost all DMAs have an unfavorable potential gradient at the outlet (e.g. long column, Vienna type) or at the inlet (nano-radial DMA). This feature prevents them from achieving a good transmission efficiency for the smallest nanoparticles. We developed a new high transmission inlet for the Caltech nano-radial DMA (nRDMA) that increases the transmission efficiency to 12 % for ions as small as 1.3 nm in mobility equivalent diameter (corresponding to 1.2×10^-4 m^2V^-1s^-1 in electrical mobility). We successfully deployed the nRDMA, equipped with the new inlet, in chamber measurements, using a Particle Size Magnifier (PSM) and a booster Condensation Particle Counter (CPC) as a counter. With this setup, we were able to measure size distributions of ions between 1.3 and 6 nm, corresponding to a mobility range from 1.2×10^-4 to 5.8×10^-6m^2V^-1s^-1. The system was modeled, tested in the laboratory and used to measure negative ions at ambient concentrations in the CLOUD 7 measurement campaign at CERN. We achieved a higher size resolution than techniques currently used in field measurements, and maintained a good transmission efficiency at moderate inlet and sheath air flows (2.5 and 30 LPM, respectively). In this paper, by measuring size distribution at high size resolution down to 1.3 nm, we extend the limit of the current technology. The current setup is limited to ion measurements. However, 20 we envision that future research focused on the charging mechanisms could extend the technique to measure neutral aerosol particles as well, so that it will be possible to measure size distributions of ambient aerosols from 1 nm to 1 μm.

KW - 114 Physical sciences

KW - ATMOSPHERIC AEROSOL-PARTICLES

U2 - 10.5194/amtd-8-5847-2015

DO - 10.5194/amtd-8-5847-2015

M3 - Article

VL - 8

SP - 5847

EP - 5876

JO - Atmospheric Measurement Techniques Discussions

JF - Atmospheric Measurement Techniques Discussions

SN - 1867-8610

ER -