Enhancing the detection efficiency of condensation particle counters for sub-2  nm particles

Barmpounis, K.; Ranjithkumar, Ananth; Schmidt‐Ott, A.; Attoui, Michel; Biskos, George

doi:10.1016/j.jaerosci.2017.12.005

Cited by 37 publications

(36 citation statements)

References 37 publications

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“…In summary, by lowering the operating temperature range by 9 K of a standard TSI 3776 UCPC and keeping DT between saturator and condenser constant, we could achieve a reduction of the cut-off diameter ðD p;50 Þ from 2.9 nm to about 2.1 nm for the neutral aerosol composition. In contrast to Barmpounis et al (2018), DT between saturator and condenser was not increased. The calculated saturation ratio profiles inside the condenser tube are not elevated by increasing DT, but due to the temperature reduction.…”

Section: Resultsmentioning

confidence: 61%

“…The particle detection efficiency depends mainly on the activation probability which is primarily a function of supersaturation and particle diameter (Barmpounis et al 2018).…”

Section: Methodsmentioning

confidence: 99%

“…In a recent paper by Barmpounis et al (2018), it has been shown that by lowering the nucleation temperature in a butanol-based CPC the saturation ratio increases. To understand heterogeneous nucleation of n-butanol vapor on nano-particles in a size-range down to about 2 nm the temperature dependence was investigated in this work.…”

Section: Introductionmentioning

confidence: 99%

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Counting efficiency determination from quantitative intercomparison between expansion and laminar flow type condensation particle counter

Tauber

Steiner

Winkler

2019

Aerosol Science and Technology

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Heterogeneous nucleation of supersaturated n-butanol vapor on neutral silver particles of different size has been investigated at variable nucleation temperatures using a fast expansion chamber and a commercial continuous flow type condensation particle counter (CPC). In addition, the theoretical supersaturation profile was calculated for the commercial CPC in order to conflate the results with the measured onset saturation ratio of the expansion type size analyzing nuclei counter (SANC). A comparison of the experimental results of the SANC measurements with the Kelvin equation shows that the heterogeneous nucleation starts below the Kelvin curve. By introducing a correction factor for the Kelvin equation based on the SANC measurements, the theoretical detection efficiency for a laminar flow type CPC could be derived. It was the first time that a validation between theoretical saturation ratio profiles and measurements conducted with different methods to generate supersaturation was achieved. We made the observation that reducing the nucleation temperature generally leads to enhanced counting efficiencies. Consequently, the cutoff diameter of regular butanol CPCs can be significantly reduced by simply lowering the condenser temperature. ARTICLE HISTORY

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Section: Resultsmentioning

confidence: 61%

“…The particle detection efficiency depends mainly on the activation probability which is primarily a function of supersaturation and particle diameter (Barmpounis et al 2018).…”

Section: Methodsmentioning

confidence: 99%

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Counting efficiency determination from quantitative intercomparison between expansion and laminar flow type condensation particle counter

Tauber

Steiner

Winkler

2019

Aerosol Science and Technology

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“…In the third and fourth channels, two TSI UCPC Model 3776 with an inlet flow rate of 1.5 L/min were implemented and operated at modified temperature settings, i.e. the saturator temperature was set to 30.1°C and the condenser temperature set at 0.1°C for enhanced 120 particle activation (Barmpounis et al, 2018;Tauber et al, 2019). A water-based TSI CPC Model 3788 was employed in the https://doi.org/10.5194/acp-2019-1123 Preprint.…”

Section: The Dma-train Experimental Setupmentioning

confidence: 99%

New Particle Formation and Sub-10 nm Size Distribution Measurements during the A-LIFE field experiment in Paphos, Cyprus

Brilke¹,

Fölker²,

Müller³

et al. 2019

Preprint

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<p><strong>Abstract.</strong> Atmospheric particle size distributions were measured in Paphos, Cyprus, during the A-LIFE (Absorbing aerosol layers in a changing climate: aging, lifetime and dynamics) field experiment from April 3&#8211;30, 2017. The newly developed DMA-train is deployed for the first time in an atmospheric environment for the direct measurement of the nucleation mode size range between 1.8&#8211;10&#8201;nm diameter. The DMA-train setup consists of seven size channels, of which five are set to fixed particle mobility diameters and two additional diameters are obtained by alternating voltage settings in one DMA every 10&#8201;s. In combination with a conventional Mobility Particle Size Spectrometer (MPSS) and an Aerodynamic Particle Sizer (APS) the complete atmospheric aerosol size distribution from 1.8&#8201;nm&#8211;10&#8201;&#181;m is covered. The focus of the A-LIFE study is to characterize new particle formation (NPF) in the Eastern Mediterranean region at a measurement site with strong local pollution sources. The nearby Paphos airport was found to be a large emission source for nucleation mode particles and we analysed the size distribution of the airport emission plumes at approximately 500&#8201;m from the main runway. The analysis yielded 9 NPF events in 27 measurement days from the combined analysis of the DMA-train, MPSS and trace gas monitors. Growth rate calculations were performed and a size-dependency of the initial growth rate (<&#8201;10&#8201;nm) is observed for one event case. Fast changes of the sub-10&#8201;nm size distribution on the timescale of a few minutes are captured by the DMA-train measurement during early particle growth and are discussed in a second event case. In 2 cases, particle formation and growth were detected in the nucleation mode size range which did not exceed the 10&#8201;nm threshold. This finding implies that NPF likely occurs more frequently than estimated from studies where the lower nanometre size regime is not covered by the size distribution measurements.</p>

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“…Hence the detection efficency η of a UCPC can be determined by comparing the number concentration of the CPC N CP C,1−3 and the total number 10 concentration N F CE as follows: By operating the CPCs at different temperature settings we were able to analyze the detection efficiency with various peak super saturation ratios (Tauber et al, 2019). The particle detection efficiency mainly depends on the activation probability which is primarily a function of supersaturation and particle diameter (Barmpounis et al, 2018). By conducting detection efficiency measurements the cut-off diameter is determined, which represents the mobility diameter where 50% of the particles can be counted in a CPC.…”

mentioning

confidence: 99%

Humidity effects on the detection of soluble and insoluble nanoparticles in butanol operated condensation particle counters

Tauber¹,

Brilke²,

Wlasits³

et al. 2019

Preprint

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Abstract. In this study the impact of humidity on heterogeneous nucleation of n-butanol onto hygroscopic and nonabsorbent particles was investigated using a fast expansion chamber and commercial continuous flow type condensation particle counters (CPCs). More specifically, we measured the activation probability of sodium chloride (NaCl) and silver (Ag) nano-particles by using n-butanol as condensing liquid with the size analyzing nuclei counter (SANC). In addition, the cut-off diameter of regular butanol based CPCs for both seed materials was measured and compared to SANC results. Our findings reveal a strong humidity dependence of NaCl particles in the sub-10 nm size range since the activation of sodium chloride seeds is enhanced with increasing relative humidity. For Ag seeds this humidity dependence was not observed, underlining the importance of molecular interactions between seed and vapor molecules. Consequently, the cut-off diameter of a butanol based CPC can be reduced significantly by increasing the relative humidity. This finding suggests that cut-off diameters of butanol CPCs under ambient conditions are likely smaller than corresponding cut-off diameters measured under clean (dry) laboratory conditions. At the same time, we caution that the humidity dependence may lead to wrong interpretations if the aerosol composition is not known.

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Enhancing the detection efficiency of condensation particle counters for sub-2 nm particles

Cited by 37 publications

References 37 publications

Counting efficiency determination from quantitative intercomparison between expansion and laminar flow type condensation particle counter

Counting efficiency determination from quantitative intercomparison between expansion and laminar flow type condensation particle counter

New Particle Formation and Sub-10 nm Size Distribution Measurements during the A-LIFE field experiment in Paphos, Cyprus

Humidity effects on the detection of soluble and insoluble nanoparticles in butanol operated condensation particle counters

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