scholarly journals Results from the CERN pilot CLOUD experiment

2010 ◽  
Vol 10 (4) ◽  
pp. 1635-1647 ◽  
Author(s):  
J. Duplissy ◽  
M. B. Enghoff ◽  
K. L. Aplin ◽  
F. Arnold ◽  
H. Aufmhoff ◽  
...  
Keyword(s):  
Sulphuric Acid ◽  
Growth Rates ◽  
Formation Rate ◽  
Detection Threshold ◽  
Proton Synchrotron ◽  
Aerosol Formation ◽  
Stringent Requirement ◽  
Pilot Experiment ◽  
Aerosol Chamber ◽  
Ion Recombination

Abstract. During a 4-week run in October–November 2006, a pilot experiment was performed at the CERN Proton Synchrotron in preparation for the Cosmics Leaving OUtdoor Droplets (CLOUD) experiment, whose aim is to study the possible influence of cosmic rays on clouds. The purpose of the pilot experiment was firstly to carry out exploratory measurements of the effect of ionising particle radiation on aerosol formation from trace H2SO4 vapour and secondly to provide technical input for the CLOUD design. A total of 44 nucleation bursts were produced and recorded, with formation rates of particles above the 3 nm detection threshold of between 0.1 and 100 cm−3s−1, and growth rates between 2 and 37 nm h−1. The corresponding H2O concentrations were typically around 106 cm−3 or less. The experimentally-measured formation rates and H2SO4 concentrations are comparable to those found in the atmosphere, supporting the idea that sulphuric acid is involved in the nucleation of atmospheric aerosols. However, sulphuric acid alone is not able to explain the observed rapid growth rates, which suggests the presence of additional trace vapours in the aerosol chamber, whose identity is unknown. By analysing the charged fraction, a few of the aerosol bursts appear to have a contribution from ion-induced nucleation and ion-ion recombination to form neutral clusters. Some indications were also found for the accelerator beam timing and intensity to influence the aerosol particle formation rate at the highest experimental SO2 concentrations of 6 ppb, although none was found at lower concentrations. Overall, the exploratory measurements provide suggestive evidence for ion-induced nucleation or ion-ion recombination as sources of aerosol particles. However in order to quantify the conditions under which ion processes become significant, improvements are needed in controlling the experimental variables and in the reproducibility of the experiments. Finally, concerning technical aspects, the most important lessons for the CLOUD design include the stringent requirement of internal cleanliness of the aerosol chamber, as well as maintenance of extremely stable temperatures (variations below 0.1 °C

scholarly journals Results from the CERN pilot CLOUD experiment

2009 ◽  
Vol 9 (5) ◽  
pp. 18235-18270 ◽  
Author(s):  
J. Duplissy ◽  
M. B. Enghoff ◽  
K. L. Aplin ◽  
F. Arnold ◽  
H. Aufmhoff ◽  
...  
Keyword(s):  
Sulphuric Acid ◽  
Growth Rates ◽  
Formation Rate ◽  
Detection Threshold ◽  
Proton Synchrotron ◽  
Aerosol Formation ◽  
Stringent Requirement ◽  
Pilot Experiment ◽  
Aerosol Chamber ◽  
Ion Recombination

Abstract. During a 4-week run in October–November 2006, a pilot experiment was performed at the CERN Proton Synchrotron in preparation for the CLOUD1 experiment, whose aim is to study the possible influence of cosmic rays on clouds. The purpose of the pilot experiment was firstly to carry out exploratory measurements of the effect of ionising particle radiation on aerosol formation from trace H2SO4 vapour and secondly to provide technical input for the CLOUD design. A total of 44 nucleation bursts were produced and recorded, with formation rates of particles above the 3 nm detection threshold of between 0.1 and 100 cm−3s−1, and growth rates between 2 and 37 nm h−1. The corresponding H2SO4 concentrations were typically around 106 cm−3 or less. The experimentally-measured formation rates and H2SO4 concentrations are comparable to those found in the atmosphere, supporting the idea that sulphuric acid is involved in the nucleation of atmospheric aerosols. However, sulphuric acid alone is not able to explain the observed rapid growth rates, which suggests the presence of additional trace vapours in the aerosol chamber, whose identity is unknown. By analysing the charged fraction, a few of the aerosol bursts appear to have a contribution from ion-induced nucleation and ion-ion recombination to form neutral clusters. Some indications were also found for the accelerator beam timing and intensity to influence the aerosol particle formation rate at the highest experimental SO2 concentrations of 6 ppb, although none was found at lower concentrations. Overall, the exploratory measurements provide suggestive evidence for ion-induced nucleation or ion-ion recombination as sources of aerosol particles. However in order to quantify the conditions under which ion processes become significant, improvements are needed in controlling the experimental variables and in the reproducibility of the experiments. Finally, concerning technical aspects, the most important lessons for the CLOUD design include the stringent requirement of internal cleanliness of the aerosol chamber, as well as maintenance of extremely stable temperatures (variations below 0.1°C). 1CLOUD is an acronym of Cosmics Leaving OUtdoor Droplets.

scholarly journals Charged and total particle formation and growth rates during EUCAARI 2007 campaign in Hyytiälä

2009 ◽  
Vol 9 (12) ◽  
pp. 4077-4089 ◽  
Author(s):  
H. E. Manninen ◽  
T. Nieminen ◽  
I. Riipinen ◽  
T. Yli-Juuti ◽  
S. Gagné ◽  
...  
Keyword(s):  
Boreal Forest ◽  
Growth Rates ◽  
Charged Particles ◽  
Particle Formation ◽  
New Particle Formation ◽  
Aerosol Formation ◽  
Total Particle ◽  
Order Of Magnitude ◽  
Ion Recombination ◽  
Particle Formation And Growth

Abstract. Despite the fact that frequent aerosol formation has been observed in various locations in the atmosphere, the overall magnitude of the new particle formation as a particle source is still unclear. In order to understand the particle formation and growth processes, we investigate the magnitudes of the particle formation and growth rates at the size where the real atmospheric nucleation and activation occurs. The relative contribution of neutral and charged particles to the new particle formation rate is also studied. The data include particle and ion number size distributions and total particle concentration measurements at a boreal forest site in Hyytiälä, Finland, during the spring 2007 EUCAARI field campaign. The total and charged particle formation rates differed from each other by approximately an order of magnitude. The median formation rates of 2 nm total and charged particles were 0.65 cm−3 s−1 and 0.03 cm−3 s−1, respectively. The median growth rates of particles in size classes 1.3–3, 3–7 and 7–20 nm were 1.9, 3.6 and 4.2 nm h−1, respectively. The calculated ion-ion recombination rates were about the same order of magnitude as the ion-induced formation rates. The results indicate that the ion-induced nucleation involving the ion-ion recombination products, i.e. ion mediated nucleation, contributes approximately 10% to the boreal forest new particle formation events.

scholarly journals New particle formation events in semi-clean South African savannah

2011 ◽  
Vol 11 (7) ◽  
pp. 3333-3346 ◽  
Author(s):  
V. Vakkari ◽  
H. Laakso ◽  
M. Kulmala ◽  
A. Laaksonen ◽  
D. Mabaso ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Growth Rate ◽  
Particle Size ◽  
Sulphuric Acid ◽  
Growth Rates ◽  
Formation Rate ◽  
Particle Formation ◽  
Size Distributions ◽  
New Particle Formation ◽  
Particle Formation And Growth

Abstract. This study is based on 18 months (20 July 2006–5 February 2008) of continuous measurements of aerosol particle size distributions, air ion size distributions, trace gas concentrations and basic meteorology in a semi-clean savannah environment in Republic of South Africa. New particle formation and growth was observed on 69% of the days and bursts of non-growing ions/sub-10 nm particles on additional 14% of the days. This new particle formation frequency is the highest reported from boundary layer so far. Also the new particle formation and growth rates were among the highest reported in the literature for continental boundary layer locations; median 10 nm formation rate was 2.2 cm−3 s−1 and median 10–30 nm growth rate 8.9 nm h−1. The median 2 nm ion formation rate was 0.5 cm−3 s−1 and the median ion growth rates were 6.2, 8.0 and 8.1 nm h−1 for size ranges 1.5–3 nm, 3–7 nm and 7–20 nm, respectively. The growth rates had a clear seasonal dependency with minimum during winter and maxima in spring and late summer. The relative contribution of estimated sulphuric acid to the growth rate was decreasing with increasing particle size and could explain more than 20% of the observed growth rate only for the 1.5–3 nm size range. Also the air mass history analysis indicated the highest formation and growth rates to be associated with the area of highest VOC (Volatile Organic Compounds) emissions following from biological activity rather than the highest estimated sulphuric acid concentrations. The frequency of new particle formation, however, increased nearly monotonously with the estimated sulphuric acid reaching 100% at H2SO4 concentration of 6 · 107 cm−3, which suggests the formation and growth to be independent of each other.

scholarly journals New particle formation events in semi-clean South African savannah

2010 ◽  
Vol 10 (12) ◽  
pp. 30777-30821 ◽  
Author(s):  
V. Vakkari ◽  
H. Laakso ◽  
M. Kulmala ◽  
A. Laaksonen ◽  
D. Mabaso ◽  
...  
Keyword(s):  
Growth Rate ◽  
Sulphuric Acid ◽  
Growth Rates ◽  
Formation Rate ◽  
Particle Formation ◽  
Size Distributions ◽  
New Particle Formation ◽  
Air Mass ◽  
History Analysis ◽  
Particle Formation And Growth

Abstract. This study is based on 18 months (20 July 2006–5 February 2008) of continuous measurements of aerosol particle size distributions, air ion size distributions, trace gas concentrations and basic meteorology in a semi-clean savannah environment in Republic of South Africa. New particle formation and growth was observed on 69% of the days and bursts of non-growing ions/sub-10 nm particles on additional 14% of the days. The new particle formation and growth rates were among the highest reported in the literature for continental boundary layer locations; median 10 nm formation rate was 2.2 cm−3s−1 and median 10–30 nm growth rate 8.9 nm h−1. The median 2 nm ion formation rate was 0.5 cm−3s−1 and the median ion growth rates were 6.2, 8.0 and 8.1 nm h−1 for size ranges 1.5–3 nm, 3–7 nm and 7–20 nm, respectively. Three different approaches were used to study the origin of the formation and growth rates: seasonal variation, air mass history analysis and estimated sulphuric acid contribution to the growth. The growth rates had a clear seasonal dependency with minimum during winter and maxima in spring and late summer and the air mass history analysis indicated the highest formation and growth rates to be associated with the area of highest VOC (Volatile Organic Compounds) emissions rather than the highest estimated sulphuric acid concentrations. The relative contribution of estimated sulphuric acid to the growth rate was decreasing with increasing particle size and could explain more than 20% of the observed growth rate only for the 1.5–3 nm size range. The implication is that the sulphuric acid alone is not enough to explain the growth, but the highest growth rates seem to originate in VOC emissions following from biological activity. The frequency of new particle formation, however, increased nearly monotonously with the estimated sulphuric acid reaching 100% at H2SO4 concentration of 4×107cm−3, which suggests the formation and growth to be independent of each other.

scholarly journals Charged and total particle formation and growth rates during EUCAARI 2007 campaign in Hyytiälä

2009 ◽  
Vol 9 (1) ◽  
pp. 5119-5151 ◽  
Author(s):  
H. E. Manninen ◽  
T. Nieminen ◽  
I. Riipinen ◽  
T. Yli-Juuti ◽  
S. Gagné ◽  
...  
Keyword(s):  
Boreal Forest ◽  
Growth Rates ◽  
Charged Particles ◽  
Particle Formation ◽  
New Particle Formation ◽  
Aerosol Formation ◽  
Total Particle ◽  
Order Of Magnitude ◽  
Ion Recombination ◽  
Particle Formation And Growth

Abstract. Despite the fact that frequent aerosol formation has been observed in various locations in the atmosphere, the overall magnitude of the new particle formation as a particle source is still unclear. In order to understand the particle formation and growth processes, we investigate the magnitudes of the particle formation and growth rates at the size where the real atmospheric nucleation and activation occurs. The relative contribution of neutral and charged particles to the new particle formation rate is also studied. The data include particle and ion number size distributions and total particle concentration measurements at a boreal forest site in Hyytiälä, Finland, during the spring 2007 EUCAARI field campaign. The total and charged particle formation rates differed from each other by approximately an order of magnitude. The median formation rates of 2 nm total and charged particles were 0.65 cm−3 s−1 and 0.03 cm−3 s−1, respectively. The median growth rates of particles in size classes 1.3–3, 3–7 and 7–30 nm were 1.9, 3.6 and 4.2 nm h−1, respectively. The calculated ion-ion recombination rates were about the same order of magnitude as the ion-induced formation rates. The results indicate that the ion-induced nucleation involving the ion-ion recombination products, i.e. ion mediated nucleation, contributes approximately 10% to the boreal forest new particle formation events.

scholarly journals A chamber study of the influence of boreal BVOC emissions and sulphuric acid on nanoparticle formation rates at ambient concentrations

2014 ◽  
Vol 14 (22) ◽  
pp. 31319-31360 ◽  
Author(s):  
M. Dal Maso ◽  
L. Liao ◽  
J. Wildt ◽  
A. Kiendler-Scharr ◽  
E. Kleist ◽  
...  
Keyword(s):  
Sulphuric Acid ◽  
Cloud Condensation Nuclei ◽  
Formation Rate ◽  
Particle Growth ◽  
Oxidation Products ◽  
Aerosol Formation ◽  
Nanoparticle Formation ◽  
Aerosol Nanoparticles ◽  
Chamber Study ◽  
Vapor Mixtures

Abstract. Aerosol formation from biogenic and anthropogenic precursor trace gases in continental background areas affects climate via altering the amount of available cloud condensation nuclei. Significant uncertainty still exists regarding the agents controlling the formation of aerosol nanoparticles. We have performed experiments in the Jülich Plant-Atmosphere Simulation Chamber with instrumentation for the detection of sulphuric acid and nanoparticles, and present the first simultaneous chamber observations of nanoparticles, sulphuric acid, and realistic levels and mixtures of biogenic volatile compounds (BVOC). We present direct laboratory observations of nanoparticle formation from sulphuric acid and realistic BVOC precursor vapor mixtures performed at atmospherically relevant concentration levels. We directly measured particle formation rates separately from particle growth rates. From this, we established that in our experiments, the formation rate was proportional to the product of sulphuric acid and biogenic VOC emission strength. The formation rates were consistent with a mechanism in which nucleating BVOC oxidation products are rapidly formed and activate with sulphuric acid. The growth rate of nanoparticles immediately after birth was best correlated with estimated products resulting from BVOC ozonolysis.

scholarly journals Aerosol formation and growth rates from chamber experiments using Kalman smoothing

2021 ◽  
Author(s):  
Matthew Ozon ◽  
Dominik Stolzenburg ◽  
Lubna Dada ◽  
Aku Seppänen ◽  
Kari E. J. Lehtinen
Keyword(s):  
Size Distribution ◽  
Growth Rates ◽  
Numerical Models ◽  
Formation Rate ◽  
Kernel Functions ◽  
The Other ◽  
Aerosol Size Distribution ◽  
Aerosol Formation ◽  
Distribution Dynamics ◽  
Kalman Smoothing

Abstract. Bayesian state estimation in the form of Kalman smoothing was applied to Differential Mobility Analyser Train (DMA-train) measurements of aerosol size distribution dynamics. Four experiments were analysed in order to estimate the aerosol size distribution, formation rate and size-dependent growth rate, as functions of time. The first analysed case was a synthetic one, generated by a detailed aerosol dynamics model, and the other three chamber experiments performed at the CERN CLOUD facility. The estimated formation and growth rates were compared with other methods used earlier for the CLOUD data and with the true values for the computer-generated synthetic experiment. The agreement in the growth rates was remarkably good for all studied cases. The formation rates matched also well, especially considering the fact that they were estimated from data given by two different instruments, the other being the Particle Size magnifier (PSM). The presented Fixed Interval Kalman Smoother (FIKS) method has clear advantages compared with earlier methods that have been applied to this kind of data. First, FIKS can reconstruct the size distribution between possible size gaps in the measurement in such a way that it is consistent with aerosol size distribution dynamics theory, and second, the method gives rise to direct and reliable estimation of size distribution and process rate uncertainties if the uncertainties in the kernel functions and numerical models are known.

scholarly journals Atmospheric sulphuric acid and aerosol formation: implications from atmospheric measurements for nucleation and early growth mechanisms

2006 ◽  
Vol 6 (12) ◽  
pp. 4079-4091 ◽  
Author(s):  
S.-L. Sihto ◽  
M. Kulmala ◽  
V.-M. Kerminen ◽  
M. Dal Maso ◽  
T. Petäjä ◽  
...  
Keyword(s):  
Time Delay ◽  
Sulphuric Acid ◽  
Acid Concentration ◽  
Particle Formation ◽  
Early Growth ◽  
Activation Mechanism ◽  
Aerosol Formation ◽  
Atmospheric Measurements ◽  
Nucleation Mechanisms ◽  
Sulphuric Acid Concentration

Abstract. We have investigated the formation and early growth of atmospheric secondary aerosol particles building on atmospheric measurements. The measurements were part of the QUEST 2 campaign which took place in spring 2003 in Hyytiälä (Finland). During the campaign numerous aerosol particle formation events occurred of which 15 were accompanied by gaseous sulphuric acid measurements. Our detailed analysis of these 15 events is focussed on nucleation and early growth (to a diameter of 3 nm) of fresh particles. It revealed that new particle formation seems to be a function of the gaseous sulphuric acid concentration to the power from one to two when the time delay between the sulphuric acid and particle number concentration is taken into account. From the time delay the growth rates of freshly nucleated particles from 1 nm to 3 nm were determined. The mean growth rate was 1.2 nm/h and it was clearly correlated with the gaseous sulphuric acid concentration. We tested two nucleation mechanisms – recently proposed cluster activation and kinetic type nucleation – as possible candidates to explain the observed dependences, and determined experimental nucleation coefficients. We found that some events are dominated by the activation mechanism and some by the kinetic mechanism. Inferred coefficients for the two nucleation mechanisms are the same order of magnitude as chemical reaction coefficients in the gas phase and they correlate with the product of gaseous sulphuric acid and ammonia concentrations. This indicates that besides gaseous sulphuric acid also ammonia has a role in nucleation.

scholarly journals A chamber study of the influence of boreal BVOC emissions and sulfuric acid on nanoparticle formation rates at ambient concentrations

2016 ◽  
Vol 16 (4) ◽  
pp. 1955-1970 ◽  
Author(s):  
M. Dal Maso ◽  
L. Liao ◽  
J. Wildt ◽  
A. Kiendler-Scharr ◽  
E. Kleist ◽  
...  
Keyword(s):  
Sulfuric Acid ◽  
Cloud Condensation Nuclei ◽  
Formation Rate ◽  
Particle Growth ◽  
Oxidation Products ◽  
Aerosol Formation ◽  
Nanoparticle Formation ◽  
Aerosol Nanoparticles ◽  
Chamber Study ◽  
Ambient Concentrations

Abstract. Aerosol formation from biogenic and anthropogenic precursor trace gases in continental background areas affects climate via altering the amount of available cloud condensation nuclei. Significant uncertainty still exists regarding the agents controlling the formation of aerosol nanoparticles. We have performed experiments in the Jülich plant–atmosphere simulation chamber with instrumentation for the detection of sulfuric acid and nanoparticles, and present the first simultaneous chamber observations of nanoparticles, sulfuric acid, and realistic levels and mixtures of biogenic volatile compounds (BVOCs). We present direct laboratory observations of nanoparticle formation from sulfuric acid and realistic BVOC precursor vapour mixtures performed at atmospherically relevant concentration levels. We directly measured particle formation rates separately from particle growth rates. From this, we established that in our experiments, the formation rate was proportional to the product of sulfuric acid and biogenic VOC emission strength. The formation rates were consistent with a mechanism in which nucleating BVOC oxidation products are rapidly formed and activate with sulfuric acid. The growth rate of nanoparticles immediately after birth was best correlated with estimated products resulting from BVOC ozonolysis.

scholarly journals Formation and characteristics of ions and charged aerosol particles in a native Australian Eucalypt forest

2008 ◽  
Vol 8 (1) ◽  
pp. 129-139 ◽  
Author(s):  
T. Suni ◽  
M. Kulmala ◽  
A. Hirsikko ◽  
T. Bergman ◽  
L. Laakso ◽  
...  
Keyword(s):  
Growth Rates ◽  
Aerosol Particles ◽  
Particle Formation ◽  
Cluster Ions ◽  
Native Forest ◽  
New Particle Formation ◽  
Aerosol Formation ◽  
Eucalypt Forest ◽  
The World ◽  
Strong Source

Abstract. Biogenic aerosol formation is likely to contribute significantly to the global aerosol load. In recent years, new-particle formation has been observed in various ecosystems around the world but hardly any measurements have taken place in the terrestrial Southern Hemisphere. Here, we report the first results of atmospheric ion and charged particle concentrations as well as of new-particle formation in a Eucalypt forest in Tumbarumba, South-East Australia, from July 2005 to October 2006. The measurements were carried out with an Air Ion Spectrometer (AIS) with a size range from 0.34 to 40 nm. The Eucalypt forest was a very strong source of new aerosol particles. Daytime aerosol formation took place on 52% of days with acceptable data, which is 2–3 times as often as in the Nordic boreal zone. Average growth rates for negative/positive 1.5–3 nm particles during these formation events were 2.89/2.68 nmh−1, respectively; for 3-7 nm particles 4.26/4.03, and for 7–20 nm particles 8.90/7.58 nmh−1, respectively. The growth rates for large ions were highest when the air was coming from the native forest which suggests that the Eucalypts were a strong source of condensable vapours. Average concentrations of cluster ions (0.34–1.8 nm) were 2400/1700 cm−3 for negative/positive ions, very high compared to most other measurements around the world. One reason behind these high concentrations could be the strong radon efflux from the soils around the Tumbarumba field site. Furthermore, comparison between night-time and daytime concentrations supported the view that cluster ions are produced close to the surface within the boundary layer also at night but that large ions are mostly produced in daytime. Finally, a previously unreported phenomenon, nocturnal aerosol formation, appeared in 32% of the analysed nights but was clustered almost entirely within six months from summer to autumn in 2006. From January to May, nocturnal formation was 2.5 times as frequent as daytime formation. Therefore, it appears that in summer and autumn, nocturnal production was the major mechanism for aerosol formation in Tumbarumba.

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