Performance of diethylene glycol based particle counters in the sub 3 nm size range [Discussion paper]

  • When studying new particle formation, the uncertainty in determining the "true" nucleation rate is considerably reduced when using Condensation Particle Counters (CPCs) capable of measuring concentrations of aerosol particles at sizes close to or even at the critical cluster size (1–2 nm). Recently CPCs, able to reliably detect particles below 2 nm in size and even close to 1 nm became available. The corrections needed to calculate nucleation rates are substantially reduced compared to scaling the observed formation rate to the nucleation rate at the critical cluster size. However, this improved instrumentation requires a careful characterization of their cut-off size and the shape of the detection efficiency curve because relatively small shifts in the cut-off size can translate into larger relative errors when measuring particles close to the cut-off size. Here we describe the development of two continuous flow CPCs using diethylene glycol (DEG) as the working fluid. The design is based on two TSI 3776 counters. Several sets of measurements to characterize their performance at different temperature settings were carried out. Furthermore two mixing-type Particle Size Magnifiers (PSM) A09 from Airmodus were characterized in parallel. One PSM was operated at the highest mixing ratio (1 L min−1 saturator flow), and the other was operated in a scanning mode, where the mixing ratios are changed periodically, resulting in a range of cut-off sizes. Different test aerosols were generated using a nano-Differential Mobility Analyzer (nano-DMA) or a high resolution DMA, to obtain detection efficiency curves for all four CPCs. One calibration setup included a high resolution mass spectrometer (APi-TOF) for the determination of the chemical composition of the generated clusters. The lowest cut-off sizes were achieved with negatively charged ammonium sulphate clusters, resulting in cut-offs of 1.4 nm for the laminar flow CPCs and 1.2 and 1.1 nm for the PSMs. A comparison of one of the laminar-flow CPCs and one of the PSMs measuring ambient and laboratory air showed good agreement between the instruments.

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Author:Daniela WimmerORCiDGND, Katrianne LehtipaloORCiDGND, Alessandro Franchin, Juha Kangasluoma, Fabian Kreissl, Christoph Andreas KürtenORCiDGND, Agnieszka Kupc, Axel Metzger, Jyri Mikkilä, Tuukka Petäjä, Francesco Riccobono, Joonas Vanhanen, Markku KulmalaORCiDGND, Joachim CurtiusORCiD
URN:urn:nbn:de:hebis:30:3-298790
DOI:https://doi.org/10.5194/amtd-6-2151-2013
ISSN:1867-8610
Parent Title (English):Atmospheric measurement techniques discussions
Publisher:Copernicus
Place of publication:Katlenburg-Lindau
Document Type:Article
Language:English
Date of Publication (online):2013/02/26
Date of first Publication:2013/02/26
Publishing Institution:Universitätsbibliothek Johann Christian Senckenberg
Release Date:2013/05/07
Volume:6
Page Number:16
First Page:2151
Last Page:2181
Note:
© Author(s) 2013. This work is distributed under the Creative Commons Attribution 3.0 License.
HeBIS-PPN:339425660
Institutes:Geowissenschaften / Geographie / Geowissenschaften
Dewey Decimal Classification:5 Naturwissenschaften und Mathematik / 55 Geowissenschaften, Geologie / 550 Geowissenschaften
Sammlungen:Universitätspublikationen
Licence (German):License LogoCreative Commons - Namensnennung 3.0