Characterization of a Modified Expansion Condensation Particle Counter for Detection of Nanometer-Sized Particles

Saghafifar, Hossein; Kürten, Andreas; Curtius, Joachim; Weiden, Sarah-Lena von der; Hassanzadeh, Smaeyl; Borrmann, Stephan

doi:10.1080/02786820902922894

Cited by 13 publications

(10 citation statements)

References 23 publications

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“…The first CPCs designed specifically for ultrafine particles were developed in the 1990s with a cutoff size around 3 nm (Stolzenburg and McMurry, 1991). The demand to measure even smaller particles -mainly to study atmospheric nucleation -has led to further CPC development, and by now several different instruments have been reported to measure in the sub-3 nm size range (Seto et al, 1997;Sgro and Fernandez de la Mora, 2004;Mordas et al, 2005;Kulmala et al, 2007a;Sipilä et al, 2008Sipilä et al, , 2009Iida et al, 2009;Lehtipalo et al, 2009Lehtipalo et al, , 2010Saghafifar et al, 2009;Vanhanen et al, 2011).…”

Section: Introductionmentioning

confidence: 99%

Performance of diethylene glycol based particle counters in the sub 3 nm size range

Wimmer¹,

Lehtipalo²,

Franchin³

et al. 2013

Preprint

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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. <br><br> 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<sup>−1</sup> 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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Section: Introductionmentioning

confidence: 99%

Performance of diethylene glycol based particle counters in the sub 3 nm size range

Wimmer¹,

Lehtipalo²,

Franchin³

et al. 2013

Preprint

View full text Add to dashboard Cite

show abstract

Section: Introductionmentioning

confidence: 99%

“…The working principle of a condensation particle counter is to expose the aerosol sample to a supersaturated vapour, which condenses on the particles, thereby making them large enough to be detected optically. At least three different methods have been used for creating the required supersaturation: adiabatic expansion (Saghafifar et al, 2009), thermal diffusion in a laminar flow (Stolzenburg and McMurry, 1991) or mixing of two flows with different thermodynamic properties .…”

Section: Introductionmentioning

confidence: 99%

Performance of diethylene glycol-based particle counters in the sub-3 nm size range

et al. 2013

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Abstract. 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. Using these instruments, the corrections needed for calculating 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. The mixing ratios are determined by varying the saturator flow, where the aerosol flow stays constant at 2.5 L min−1. Different test aerosols were generated using a nano-differential mobility analyser (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 sulfate 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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“…4 Condensation particle counters measure nanomaterial number concentration in gas suspension by optical detection after growth of the particles to a detectable size through the condensation of volatile species such as butanol or water. 5 Nanomaterials may also become aggregated to different degrees in various solutions. Generally, studies to date have examined the effect of different suspension media on aggregation of nanomaterials in relation to human health effects.…”

Section: Characteristics Of Nanomaterialsmentioning

confidence: 99%

Risk management of nanomaterials

Gwinn

Tran

2010

WIREs Nanomed Nanobiotechnol

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Nanotechnology has become the focus of a large amount of scientific, political, and financial interest. Limited information on the exposure to nanomaterials is available, with only a few occupational exposure studies having been performed. While laboratory animal studies on the biological effects of some nanomaterials have been published, no epidemiological studies have been reported to date. This lack of data on exposure and human health effects hinders risk assessment of these materials. As the use of nanomaterials increases rapidly, it is of vital importance that the risk assessment community understands the complexities of the issues surrounding the manufacture, use and disposal of nanomaterials, the potential of environmental and occupational exposure to human populations, as well as adverse health outcomes. For this to happen, it is in many ways necessary for the scientific community to also understand what questions risk assessors need to ask, and what research will best answer them. Risk management of nanomaterials requires more information as to the human and ecological effects of exposure to various nanomaterials. At this time, there are no specific regulations for nanomaterials, but a few efforts to include nanomaterials under existing environmental regulations have begun. The purpose of this article is to describe the potential regulations for nanomaterials, and the current issues related to the risk assessment of nanomaterials.

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Characterization of a Modified Expansion Condensation Particle Counter for Detection of Nanometer-Sized Particles

Cited by 13 publications

References 23 publications

Performance of diethylene glycol based particle counters in the sub 3 nm size range

Performance of diethylene glycol based particle counters in the sub 3 nm size range

Performance of diethylene glycol-based particle counters in the sub-3 nm size range

Risk management of nanomaterials

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