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

Voigtländer, Jens; Duplissy, Jonathan; Rondo, Linda; Kürten, Andreas; Stratmann, Frank

doi:10.5194/acp-12-2205-2012

Cited by 50 publications

(46 citation statements)

References 28 publications

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“…All gas pipes are made from stainless steel to avoid contamination, and chamber and gas seals are chemically inert gold coated metal. Two fans running in counter flow ensure a good mixture of the gases in the chamber 35 . Traces of contaminants, for example, low molecular weight volatile organic compounds (VOCs) 36 or ammonia 37 , were sometimes observed in the chamber.…”

Section: Methodsmentioning

confidence: 99%

The role of low-volatility organic compounds in initial particle growth in the atmosphere

Tröstl

Chuang

Gordon

et al. 2016

Nature

630

729

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About half of present-day cloud condensation nuclei originate from atmospheric nucleation, frequently appearing as a burst of new particles near midday 1 . Atmospheric observations show that the growth rate of new particles often accelerates when the diameter of the particles is between one and ten nanometres 2,3 . In this critical size range, new particles are most likely to be lost by coagulation with pre-existing particles 4 , thereby failing to form new cloud condensation nuclei that are typically 50 to 100 nanometres across. Sulfuric acid vapour is often involved in nucleation but is too scarce to explain most subsequent growth 5,6 , leaving organic vapours as the most plausible alternative, at least in the planetary boundary layer 7-10 . Although recent studies [11][12][13] predict that low-volatility organic vapours contribute during initial growth, direct evidence has been lacking. The accelerating growth may result from increased photolytic production of condensable organic species in the afternoon 2 , and the presence of a possible Kelvin (curvature) effect, which inhibits organic vapour condensation on the smallest particles (the nano-Köhler theory) 2,14 , has so far remained ambiguous. Here we present experiments performed in a large chamber under atmospheric conditions that investigate the role of organic vapours in the initial growth of nucleated organic particles in the absence of inorganic acids and bases such as sulfuric acid or ammonia and amines, respectively. Using data from the same set of experiments, it has been shown 15 that organic vapours alone can drive nucleation. We focus on the growth of nucleated particles and find that the organic vapours that drive initial growth have extremely low volatilities (saturation concentration less than 10 −4.5 micrograms per cubic metre). As the particles increase in size and the Kelvin barrier falls, subsequent growth is primarily due to more abundant organic vapours of slightly higher volatility (saturation concentrations of 10 −4.5 to 10 −0.5 micrograms per cubic metre). We present a particle growth model that quantitatively reproduces our measurements. Furthermore, we implement a parameterization of the first steps of growth in a global aerosol model and find that concentrations of atmospheric cloud concentration nuclei can change substantially in response, that is, by up to 50 per cent in comparison with previously assumed growth rate parameterizations.Two measurement campaigns at the CERN CLOUD (Cosmics Leaving OUtdoor Droplets) chamber (Methods) focused on aerosol growth with different levels of sulfuric acid and α-pinene oxidation products. With the chamber at 278 K and 38% relative humidity, tropospheric concentrations of α-pinene, ozone (O 3 ) and SO 2 were introduced (see Extended Data Table 1). Using various instruments (Methods and Extended Data Fig. 1) we measured the behaviour of freshly nucleated particles of 1-2 nm diameter and their subsequent growth up to 80 nm. Two chemical ionization mass spectrometers (Methods) using nitrate as th...

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Section: Methodsmentioning

confidence: 99%

The role of low-volatility organic compounds in initial particle growth in the atmosphere

Tröstl

Chuang

Gordon

et al. 2016

Nature

630

729

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“…The lower limit is uncertain; low concentrations of NH 3 or other bases, such as amines, remain challenging to measure accurately in the atmosphere (e.g., Chang et al, 2003;Huang et al, 2009;von Bobrutzki et al, 2010;VandenBoer et al, 2011). However, recent laboratory experiments have shown a great enhancement of the formation of particles from H 2 SO 4 by the addition of only tens of parts per trillion by volume of NH 3 or just a few parts per trillion by volume of dimethylamine .…”

Section: S Schobesberger Et Al: On the Composition Of Ammonia-sulfumentioning

confidence: 99%

“…The chamber is usually operated at an overpressure of 5 mbar to avoid contamination from outside the chamber. A pair of fans facilitate the mixing of the chamber contents (Voigtländer et al, 2012). The inside of the chamber is irradiated on demand by UV light from the top of the chamber .…”

Section: The Cloud Chambermentioning

confidence: 99%

On the composition of ammonia–sulfuric-acid ion clusters during aerosol particle formation

et al. 2015

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Abstract. The formation of particles from precursor vapors is an important source of atmospheric aerosol. Research at the Cosmics Leaving OUtdoor Droplets (CLOUD) facility at CERN tries to elucidate which vapors are responsible for this new-particle formation, and how in detail it proceeds. Initial measurement campaigns at the CLOUD stainless-steel aerosol chamber focused on investigating particle formation from ammonia (NH 3 ) and sulfuric acid (H 2 SO 4 ). Experiments were conducted in the presence of water, ozone and sulfur dioxide. Contaminant trace gases were suppressed at the technological limit. For this study, we mapped out the compositions of small NH 3 -H 2 SO 4 clusters over a wide range of atmospherically relevant environmental conditions. We covered [NH 3 ] in the range from < 2 to 1400 pptv, [H 2 SO 4 ] from 3.3 × 10 6 to 1.4 × 10 9 cm −3 (0.1 to 56 pptv), and a temperature range from −25 to +20 • C. Negatively and positively charged clusters were directly measured by an atmospheric pressure interface time-of-flight (APi-TOF)Published by Copernicus Publications on behalf of the European Geosciences Union. S. Schobesberger et al.: On the composition of ammonia-sulfuric-acid clustersmass spectrometer, as they initially formed from gas-phase NH 3 and H 2 SO 4 , and then grew to larger clusters containing more than 50 molecules of NH 3 and H 2 SO 4 , corresponding to mobility-equivalent diameters greater than 2 nm. Water molecules evaporate from these clusters during sampling and are not observed. We found that the composition of the NH 3 -H 2 SO 4 clusters is primarily determined by the ratio of gas-phase concentrations [NH 3 ] is mostly larger than 10. We compared our results from CLOUD with APi-TOF measurements of NH 3 -H 2 SO 4 anion clusters during new-particle formation in the Finnish boreal forest. However, the exact role of NH 3 -H 2 SO 4 clusters in boundary layer particle formation remains to be resolved.

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“…A fiber optic system (Kupc et al, 2011) feeds UV light into the chamber, which initiates the photolytic production of sulfuric acid when H 2 O, O 2 , O 3 , and SO 2 are present. Two mixing fans continuously stir the air inside the chamber, assuring its homogeneity (Voigtländer et al, 2012).…”

Section: Cloud Chambermentioning

confidence: 99%

Thermodynamics of the formation of sulfuric acid dimers in the binary (H2SO4–H2O) and ternary (H2SO4–H2O–NH3) system

Kürten¹,

Münch

Rondo

et al. 2015

Atmos. Chem. Phys.

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Abstract. Sulfuric acid is an important gas influencing atmospheric new particle formation (NPF). Both the binary (H 2 SO 4 -H 2 O) system and the ternary system involving ammonia (H 2 SO 4 -H 2 O-NH 3 ) may be important in the free troposphere. An essential step in the nucleation of aerosol particles from gas-phase precursors is the formation of a dimer, so an understanding of the thermodynamics of dimer formation over a wide range of atmospheric conditions is essential to describe NPF. We have used the CLOUD chamber to conduct nucleation experiments for these systems at temperatures from 208 to 248 K. Neutral monomer and dimer concentrations of sulfuric acid were measured using a chemical ionization mass spectrometer (CIMS). From these measurements, dimer evaporation rates in the binary system were derived for temperatures of 208 and 223 K. We compare these results to literature data from a previous study that was conducted at higher temperatures but is in good agreement with the present study. For the ternary system the formation of Published by Copernicus Publications on behalf of the European Geosciences Union. A. Kürten et al.: Thermodynamics of the formation of sulfuric acid dimersH 2 SO 4 q NH 3 is very likely an essential step in the formation of sulfuric acid dimers, which were measured at 210, 223, and 248 K. We estimate the thermodynamic properties (dH and dS) of the H 2 SO 4 q NH 3 cluster using a simple heuristic model and the measured data. Furthermore, we report the first measurements of large neutral sulfuric acid clusters containing as many as 10 sulfuric acid molecules for the binary system using chemical ionization-atmospheric pressure interface time-of-flight (CI-APi-TOF) mass spectrometry.

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

Cited by 50 publications

References 28 publications

The role of low-volatility organic compounds in initial particle growth in the atmosphere

The role of low-volatility organic compounds in initial particle growth in the atmosphere

On the composition of ammonia–sulfuric-acid ion clusters during aerosol particle formation

Thermodynamics of the formation of sulfuric acid dimers in the binary (H<sub>2</sub>SO<sub>4</sub>–H<sub>2</sub>O) and ternary (H<sub>2</sub>SO<sub>4</sub>–H<sub>2</sub>O–NH<sub>3</sub>) system

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

Cited by 50 publications

References 28 publications

The role of low-volatility organic compounds in initial particle growth in the atmosphere

The role of low-volatility organic compounds in initial particle growth in the atmosphere

On the composition of ammonia–sulfuric-acid ion clusters during aerosol particle formation

Thermodynamics of the formation of sulfuric acid dimers in the binary (H&lt;sub&gt;2&lt;/sub&gt;SO&lt;sub&gt;4&lt;/sub&gt;–H&lt;sub&gt;2&lt;/sub&gt;O) and ternary (H&lt;sub&gt;2&lt;/sub&gt;SO&lt;sub&gt;4&lt;/sub&gt;–H&lt;sub&gt;2&lt;/sub&gt;O–NH&lt;sub&gt;3&lt;/sub&gt;) system

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Thermodynamics of the formation of sulfuric acid dimers in the binary (H<sub>2</sub>SO<sub>4</sub>–H<sub>2</sub>O) and ternary (H<sub>2</sub>SO<sub>4</sub>–H<sub>2</sub>O–NH<sub>3</sub>) system