Homogeneous nucleation of sulfuric acid and water mixture: experimental setup and first results

Brus, David; Hyvärinen, Antti; Viisanen, Y.; Kulmala, Markku; Lihavainen, Heikki

doi:10.5194/acp-10-2631-2010

Cited by 45 publications

(114 citation statements)

References 29 publications

(45 reference statements)

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“…The detailed comparison to other literature data concerning sulfuric acid -water system is given in our previous publication Brus et al (2010), however the discrepancy was found in the results of this study compared to data published earlier . In our earlier study the method of bubblers was used to estimate concentration and the losses of sulfuric acid along the flow tube as the total sulfate (SO 2− 4 ) concentration obtained via ion chromatography (IC) analysis.…”

Section: Comparison To Our Previous Datacontrasting

confidence: 56%

“…The wall loss factor (WLF) increases with relative humidity, which is due to presence of temperature gradient in first 50 cm in the nucleation chamber, see Brus et al (2010) for details. The presence of temperature gradient (both axial and radial) imposes thermophoretic force towards the cooled nucleation chamber wall (set to 25 • C) and also increases the value of diffusion coefficient, thus increasing WLF in first 50 cm.…”

Section: H 2 So 4 Lossesmentioning

confidence: 99%

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Homogenous nucleation of sulfuric acid and water at close to atmospherically relevant conditions

et al. 2011

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Abstract. In this study the homogeneous nucleation rates in the system of sulfuric acid and water were measured by using a flow tube technique. The goal was to directly compare particle formation rates obtained from atmospheric measurements with nucleation rates of freshly nucleated particles measured with particle size magnifier (PSM) which has detection efficiency of unity for particles having mobility diameter of 1.5 nm. The gas phase sulfuric acid concentration in this study was measured with the chemical ionization mass spectrometer (CIMS), commonly used in field measurements. The wall losses of sulfuric acid were estimated from measured concentration profiles along the flow tube. The initial concentrations of sulfuric acid estimated from loss measurements ranged from 10 8 to 3 × 10 9 molecules cm −3 . The nucleation rates obtained in this study cover about three orders of magnitude from 10 −1 to 10 2 cm −3 s −1 for commercial ultrafine condensation particle counter (UCPC) TSI model 3025A and from 10 1 to 10 4 cm −3 s −1 for PSM. The nucleation rates and the slopes (dlnJ/dln [H 2 SO 4 ]) show satisfactory agreement when compared to empirical kinetic and activation models and the latest atmospheric nucleation data. To the best of our knowledge, this is the first experimental work providing temperature dependent nucleation rate measurements using a high efficiency particle counter with a cutoff-size of 1.5 nm together with direct measurements of gas phase sulfuric acid concentration.

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Section: Comparison To Our Previous Datacontrasting

confidence: 56%

Section: H 2 So 4 Lossesmentioning

confidence: 99%

Homogenous nucleation of sulfuric acid and water at close to atmospherically relevant conditions

et al. 2011

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“…Furthermore, binary diffusion coefficients of 0.09 cm 2 s −1 (H 2 SO 4 in air) and 0.06 cm 2 s −1 (H 2 SO 4 in H 2 O) were applied in the simulations (Marti et al, 1997;Hanson and Eisele, 2000;Brus et al, 2010). These values are comparable to values determined using the methods of Fuller (FSG, Fuller et al, 1966), FSG-LaBas (Lyman, 1990) or Wilcke and Lee (WL, Wilke and Lee, 1955), which yield 0.11 m 2 s −1 , 0.093 m 2 s −1 , respectively 0.1 m 2 s −1 .…”

Section: Simulation Resultsmentioning

confidence: 99%

Numerical simulations of mixing conditions and aerosol dynamics in the CERN CLOUD chamber

et al. 2012

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Abstract.To study the effect of galactic cosmic rays on aerosols and clouds, the Cosmics Leaving OUtdoor Droplets (CLOUD) project was established. Experiments are carried out at a 26.1 m 3 tank at CERN (Switzerland). In the experiments, the effect of ionizing radiation on H 2 SO 4 particle formation and growth is investigated. To evaluate the experimental configuration, the experiment was simulated using a coupled multidimensional computational fluid dynamics (CFD) -particle model. In the model the coupled fields of gas/vapor species, temperature, flow velocity and particle properties were computed to investigate mixing state and mixing times of the CLOUD tank's contents. Simulation results show that a 1-fan configuration, as used in first experiments, may not be sufficient to ensure a homogeneously mixed chamber. To mix the tank properly, two fans and sufficiently high fan speeds are necessary. The 1/e response times for instantaneous changes of wall temperature and saturation ratio were found to be in the order of few minutes. Particle nucleation and growth was also simulated and particle number size distribution properties of the freshly nucleated particles (particle number, mean size, standard deviation of the assumed log-normal distribution) were found to be distributed over the tank's volume similar to the gas species.

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“…The nucleation experiments were carried out in a laminar flow tube at the Finnish Meteorological Institute, Helsinki, Finland. The detailed description of the flow tube and the operational principle has been presented and discussed in detail by Brus et al (2010) and Neitola et al (2013).…”

Section: Methodsmentioning

confidence: 99%

“…At the outlet of the flow tube, the number concentrations of the produced particles were measured using an Ultrafine Condensation Particle Counter (UCPC, Model 3776, TSI Inc., USA). The same modification to UCPC TSI 3776 has been done previously, as described in Brus et al (2010), to obtain a d 50 cut-off of 2.25 nm. The saturator temperature was increased from a nominal 39 • C up to 40 • C, and the condenser temperature was decreased from a nominal 10 • C down to 8 • C. At these new temperatures no homogenous nucleation was observed inside the counter.…”

Section: Measurements and Experimental Set-upmentioning

confidence: 99%

Growth of sulphuric acid nanoparticles under wet and dry conditions

et al. 2014

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Abstract. New particle formation, which greatly influences the number concentrations and size distributions of an atmospheric aerosol, is often followed by a rapid growth of freshly formed particles. The initial growth of newly formed aerosol is the crucial process determining the fraction of nucleated particles growing to cloud condensation nuclei sizes, which have a significant influence on climate. In this study, we report the laboratory observations of the growth of nanoparticles produced by nucleation of H 2 SO 4 and water in a laminar flow tube at temperatures of 283, 293 and 303 K, under dry (a relative humidity of 1 %) and wet conditions (relative humidity of 30 %) and residence times of 30, 45, 60 and 90 s. The initial H 2 SO 4 concentration spans the range from 2 × 10 8 to 1.4 × 10 10 molecule cm −3 and the calculated wall losses of H 2 SO 4 were assumed to be diffusion limited. The detected particle number concentrations, measured by the Ultrafine Condensation Particle Counter (UCPC) and Differential Mobility Particle Sizer (DMPS), were found to depend strongly on the residence time. Hygroscopic particle growth, presented by growth factors, was found to be in good agreement with the previously reported studies. The experimental growth rates ranged from 20 nm h −1 to 890 nm h −1 at relative humidity (RH) 1 % and from 7 nm h −1 to 980 nm h −1 at RH 30 % and were found to increase significantly with the increasing concentration of H 2 SO 4 . Increases in the nucleation temperature had a slight enhancing effect on the growth rates under dry conditions. The influence of relative humidity on growth was not consistent -at lower H 2 SO 4 concentrations, the growth rates were higher under dry conditions while at H 2 SO 4 concentrations greater than 1 × 10 9 molecule cm −3 , the growth rates were higher under wet conditions. The growth rates show only a weak dependence on the residence time. The experimental observations were compared with predictions made using a numerical model, which investigates the growth of particles with three different extents of neutralization by ammonia, NH 3 : (1) pure H 2 SO 4 -H 2 O particles; (2) particles formed by ammonium bisulphate, (NH 4 )HSO 4 ; (3) particles formed by ammonium sulphate, (NH 4 ) 2 SO 4 . The highest growth rates were found for ammonium sulphate particles. Since the model accounting for the initial H 2 SO 4 concentration predicted the experimental growth rates correctly, our results suggest that the commonly presumed diffusional wall losses of H 2 SO 4 in case of long-lasting experiments are not so significant. We therefore assume that there are not only losses of H 2 SO 4 on the wall, but also a flux of H 2 SO 4 molecules from the wall into the flow tube, the effect being more profound under dry conditions and at higher temperatures of the tube wall. Based on a comparison with the atmospheric observations, our results indicate that sulphuric acid alone cannot explain the growth rates of particles formed in the atmosphere.

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Homogeneous nucleation of sulfuric acid and water mixture: experimental setup and first results

Cited by 45 publications

References 29 publications

Homogenous nucleation of sulfuric acid and water at close to atmospherically relevant conditions

Homogenous nucleation of sulfuric acid and water at close to atmospherically relevant conditions

Numerical simulations of mixing conditions and aerosol dynamics in the CERN CLOUD chamber

Growth of sulphuric acid nanoparticles under wet and dry conditions

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