Effect of ions on the measurement of sulphuric acid in the CLOUD experiment at CERN

Abstract. Ternary aerosol nucleation experiments were conducted in the CLOUD chamber at CERN in order to investigate the influence of ions on new particle formation. Neutral and ion-induced nucleation experiments, i.e., with and without the presence of ions, were carried out under precisely controlled conditions. The sulphuric acid concentration was measured with a Chemical Ionization Mass Spectrometer (CIMS) during the new particle formation experiments. The added ternary trace gases were ammonia (NH3), dimethylamine (DMA, C2H7N) or oxidised products of pinanediol (PD, C10H18O2). When pinanediol was introduced into the chamber, an increase in the mass spectrometric signal used to determine the sulphuric acid concentration (m/z 97, i.e., HSO4−) was observed due to ions from the CLOUD chamber. The enhancement was only observed during ion-induced nucleation measurements by using either galactic cosmic rays (GCR) or the proton synchrotron (PS) pion beam for the ion generation, respectively. The ion effect typically involved an increase in the apparent sulphuric acid concentration by a factor of ~2 to 3 and was qualitatively verified by the ion measurements by an Atmospheric Pressure interface-Time Of Flight (APi-TOF) mass spectrometer. By applying a high voltage (HV) clearing field inside the CLOUD chamber the ion effect on the CIMS measurement was completely eliminated since, under these conditions, small ions are swept from the chamber in about one second. In order to exclude the ion effect and to provide corrected sulphuric acid concentrations during the GCR and PS beam nucleation experiments, a parameterisation was derived that utilizes the trace gas concentrations and the UV light intensity as input parameters. Atmospheric sulphuric acid measurements with a CIMS showed an insignificant ion effect.

Download Full-text

Effect of ions on the measurement of sulfuric acid in the CLOUD experiment at CERN

Atmospheric Measurement Techniques ◽

10.5194/amt-7-3849-2014 ◽

2014 ◽

Vol 7 (11) ◽

pp. 3849-3859 ◽

Cited By ~ 5

Author(s):

L. Rondo ◽

A. Kürten ◽

S. Ehrhart ◽

S. Schobesberger ◽

A. Franchin ◽

...

Keyword(s):

Sulfuric Acid ◽

Mass Spectrometer ◽

Acid Concentration ◽

Uv Light ◽

Sulfuric Acid Concentration ◽

Particle Formation ◽

Galactic Cosmic Rays ◽

Cloud Chamber ◽

Proton Synchrotron ◽

New Particle Formation

Abstract. Ternary aerosol nucleation experiments were conducted in the CLOUD chamber at CERN in order to investigate the influence of ions on new particle formation. Neutral and ion-induced nucleation experiments, i.e. without and with the presence of ions, respectively, were carried out under precisely controlled conditions. The sulfuric acid concentration was measured with a chemical ionisation mass spectrometer (CIMS) during the new particle formation experiments. The added ternary trace gases were ammonia (NH3), dimethylamine (DMA, C2H7N) or oxidised products of pinanediol (PD, C10H18O2). When pinanediol was introduced into the chamber, an increase in the mass spectrometric signal used to determine the sulfuric acid concentration (m/z 97, i.e. HSO4−) was observed due to ions from the CLOUD chamber. The enhancement was only observed during ion-induced nucleation measurements by using either galactic cosmic rays (GCRs) or the proton synchrotron (PS) pion beam for the ion generation, respectively. The ion effect typically involved an increase in the apparent sulfuric acid concentration by a factor of ~ 2 to 3 and was qualitatively verified by the ion measurements with an atmospheric-pressure interface-time of flight (APi-TOF) mass spectrometer. By applying a high-voltage (HV) clearing field inside the CLOUD chamber, the ion effect on the CIMS measurement was completely eliminated since, under these conditions, small ions are swept from the chamber in about 1 s. In order to exclude the ion effect and to provide corrected sulfuric acid concentrations during the GCR and PS beam nucleation experiments, a parameterisation was derived that utilises the trace gas concentrations and the UV light intensity as input parameters. Atmospheric sulfuric acid measurements with a CIMS showed an insignificant ion effect.

Download Full-text

On the formation of sulphuric acid-amine clusters in varying atmospheric conditions and its influence on atmospheric new particle formation

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-12-11485-2012 ◽

2012 ◽

Vol 12 (5) ◽

pp. 11485-11537 ◽

Cited By ~ 1

Author(s):

P. Paasonen ◽

T. Olenius ◽

O. Kupiainen ◽

T. Kurtén ◽

T. Petäjä ◽

...

Keyword(s):

Relative Humidity ◽

Sulphuric Acid ◽

Acid Concentration ◽

Formation Rate ◽

Particle Formation ◽

Atmospheric Conditions ◽

New Particle Formation ◽

Atmospheric Particle ◽

Atmospheric Observations ◽

Sulphuric Acid Concentration

Abstract. Sulphuric acid is a key component in atmospheric new particle formation. However, sulphuric acid alone does not form stable enough clusters to initiate particle formation in atmospheric conditions. Strong bases, such as amines, have been suggested to stabilize sulphuric acid clusters and thus participate in particle formation. We modelled the formation rate of clusters with two sulphuric acid and two amine molecules (JA2B2) at varying atmospherically relevant conditions with respect to concentrations of sulphuric acid ([H2SO4]), dimethylamine ([DMA]) and trimethylamine ([TMA]), temperature and relative humidity (RH). The modelled formation rates JA2B2 were functions of sulphuric acid concentration with close to quadratic dependence, which is in good agreement with atmospheric observations of the connection between the particle formation rate and sulphuric acid concentration. The coefficients KA2B2 connecting the cluster formation rate and sulphuric acid concentrations as JA2B2 = KA2B2[H2SO4]2 turned out to depend also on amine concentrations, temperature and relative humidity. We tested how the model results change if the clusters with two sulphuric acid and two amine molecules are assumed to act as seeds for heterogeneous nucleation of organic vapours (other than amines) with higher atmospheric concentrations than sulphuric acid. We also compared the modelled coefficients KA2B2 with the corresponding coefficients calculated from the atmospheric observations (Kobs) from environments with varying temperatures and levels of anthropogenic influence. By taking into account the modelled behaviour of JA2B2 as a function of [H2SO4], temperature and RH, the atmospheric particle formation rate was reproduced more closely than with the traditional semi-empirical formulae based on sulphuric acid concentration only. The formation rates of clusters with two sulphuric acid and two amine molecules with different amine compositions (DMA or TMA or one of both) had different responses to varying meteorological conditions and concentrations of vapours participating to particle formation. The observed inverse proportionality of the coefficient Kobs with RH and temperature agreed best with the modelled coefficient KA2B2 related to formation of a~cluster with two H2SO4 and one or two TMA molecules, assuming that these clusters can grow in collisions with abundant organic vapour molecules. In case this assumption is valid, our results suggest that the formation rate of clusters with at least two of both sulphuric acid and amine molecules might be the rate-limiting step for atmospheric particle formation. More generally, our analysis elucidates the sensitivity of the atmospheric particle formation rate to meteorological variables and concentrations of vapours participating in particle formation (also other than H2SO4).

Download Full-text

On the formation of sulphuric acid – amine clusters in varying atmospheric conditions and its influence on atmospheric new particle formation

Atmospheric Chemistry and Physics ◽

10.5194/acp-12-9113-2012 ◽

2012 ◽

Vol 12 (19) ◽

pp. 9113-9133 ◽

Cited By ~ 88

Author(s):

P. Paasonen ◽

T. Olenius ◽

O. Kupiainen ◽

T. Kurtén ◽

T. Petäjä ◽

...

Keyword(s):

Relative Humidity ◽

Sulphuric Acid ◽

Acid Concentration ◽

Formation Rate ◽

Particle Formation ◽

Atmospheric Conditions ◽

New Particle Formation ◽

Atmospheric Particle ◽

Atmospheric Observations ◽

Sulphuric Acid Concentration

Abstract. Sulphuric acid is a key component in atmospheric new particle formation. However, sulphuric acid alone does not form stable enough clusters to initiate particle formation in atmospheric conditions. Strong bases, such as amines, have been suggested to stabilize sulphuric acid clusters and thus participate in particle formation. We modelled the formation rate of clusters with two sulphuric acid and two amine molecules (JA2B2) at varying atmospherically relevant conditions with respect to concentrations of sulphuric acid ([H2SO4]), dimethylamine ([DMA]) and trimethylamine ([TMA]), temperature and relative humidity (RH). We also tested how the model results change if we assume that the clusters with two sulphuric acid and two amine molecules would act as seeds for heterogeneous nucleation of organic vapours (other than amines) with higher atmospheric concentrations than sulphuric acid. The modelled formation rates JA2B2 were functions of sulphuric acid concentration with close to quadratic dependence, which is in good agreement with atmospheric observations of the connection between the particle formation rate and sulphuric acid concentration. The coefficients KA2B2 connecting the cluster formation rate and sulphuric acid concentrations as JA2B2=KA2B2[H2SO4]2 turned out to depend also on amine concentrations, temperature and relative humidity. We compared the modelled coefficients KA2B2 with the corresponding coefficients calculated from the atmospheric observations (Kobs) from environments with varying temperatures and levels of anthropogenic influence. By taking into account the modelled behaviour of JA2B2 as a function of [H2SO4], temperature and RH, the atmospheric particle formation rate was reproduced more closely than with the traditional semi-empirical formulae based on sulphuric acid concentration only. The formation rates of clusters with two sulphuric acid and two amine molecules with different amine compositions (DMA or TMA or one of both) had different responses to varying meteorological conditions and concentrations of vapours participating in particle formation. The observed inverse proportionality of the coefficient Kobs with RH and temperature agreed best with the modelled coefficient KA2B2 related to formation of a cluster with two H2SO4 and one or two TMA molecules, assuming that these clusters can grow in collisions with abundant organic vapour molecules. In case this assumption is valid, our results suggest that the formation rate of clusters with at least two of both sulphuric acid and amine molecules might be the rate-limiting step for atmospheric particle formation. More generally, our analysis elucidates the sensitivity of the atmospheric particle formation rate to meteorological variables and concentrations of vapours participating in particle formation (also other than H2SO4).

Download Full-text

On the roles of sulphuric acid and low-volatility organic vapours in the initial steps of atmospheric new particle formation

Atmospheric Chemistry and Physics ◽

10.5194/acp-10-11223-2010 ◽

2010 ◽

Vol 10 (22) ◽

pp. 11223-11242 ◽

Cited By ~ 199

Author(s):

P. Paasonen ◽

T. Nieminen ◽

E. Asmi ◽

H. E. Manninen ◽

T. Petäjä ◽

...

Keyword(s):

Sulphuric Acid ◽

Acid Concentration ◽

Nucleation Rate ◽

Formation Rate ◽

Particle Formation ◽

New Particle Formation ◽

Relative Contribution ◽

Homogenous Nucleation ◽

Order Of Magnitude ◽

Sulphuric Acid Concentration

Abstract. Sulphuric acid and organic vapours have been identified as the key components in the ubiquitous secondary new particle formation in the atmosphere. In order to assess their relative contribution and spatial variability, we analysed altogether 36 new particle formation events observed at four European measurement sites during EUCAARI campaigns in 2007–2009. We tested models of several different nucleation mechanisms coupling the formation rate of neutral particles (J) with the concentration of sulphuric acid ([H2SO4]) or low-volatility organic vapours ([org]) condensing on sub-4 nm particles, or with a combination of both concentrations. Furthermore, we determined the related nucleation coefficients connecting the neutral nucleation rate J with the vapour concentrations in each mechanism. The main goal of the study was to identify the mechanism of new particle formation and subsequent growth that minimizes the difference between the modelled and measured nucleation rates. At three out of four measurement sites – Hyytiälä (Finland), Melpitz (Germany) and San Pietro Capofiume (Italy) – the nucleation rate was closely connected to squared sulphuric acid concentration, whereas in Hohenpeissenberg (Germany) the low-volatility organic vapours were observed to be dominant. However, the nucleation rate at the sulphuric acid dominant sites could not be described with sulphuric acid concentration and a single value of the nucleation coefficient, as K in J=K [H2SO4]2, but the median coefficients for different sites varied over an order of magnitude. This inter-site variation was substantially smaller when the heteromolecular homogenous nucleation between H2SO4 and organic vapours was assumed to take place in addition to homogenous nucleation of H2SO4 alone, i.e., J=KSA1[H2SO4]2+KSA2[H2SO4][org]. By adding in this equation a term describing homomolecular organic vapour nucleation, Ks3[org]2, equally good results were achieved. In general, our results suggest that organic vapours do play a role, not only in the condensational growth of the particles, but also in the nucleation process, with a site-specific degree.

Download Full-text

On the roles of sulphuric acid and low-volatility organic vapours in the initial steps of atmospheric new particle formation

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-10-11795-2010 ◽

2010 ◽

Vol 10 (5) ◽

pp. 11795-11850 ◽

Cited By ~ 9

Author(s):

P. Paasonen ◽

T. Nieminen ◽

E. Asmi ◽

H. E. Manninen ◽

T. Petäjä ◽

...

Keyword(s):

Sulphuric Acid ◽

Acid Concentration ◽

Nucleation Rate ◽

Formation Rate ◽

Particle Formation ◽

New Particle Formation ◽

Relative Contribution ◽

Homogenous Nucleation ◽

Condensational Growth ◽

Sulphuric Acid Concentration

Abstract. Sulphuric acid and organic vapours have been identified as the key components in the ubiquitous secondary new particle formation in the atmosphere. In order to assess their relative contribution and spatial variability, we analyzed altogether 36 new particle formation events observed at four European measurement sites during EUCAARI campaigns in 2007–2009. We tested models of several different nucleation mechanisms coupling the formation rate of neutral particles (J) with the concentration of sulphuric acid ([H2SO4]) or low-volatility organic vapours ([org]) condensing on sub-4 nm particles, or with a combination of both concentrations. Furthermore, we determined the related nucleation coefficients connecting the neutral nucleation rate J with the vapour concentrations in each mechanism. The main goal of the study was to identify the mechanism of new particle formation and subsequent growth that minimizes the difference between the modeled and measured nucleation rates. At three out of four measurement sites – Hyytiälä (Finland), Melpitz (Germany) and San Pietro Capofiume (Italy) – the nucleation rate was closely connected to squared sulphuric acid concentration, whereas in Hohenpeissenberg (Germany) the low-volatility organic vapours were observed to be dominant. However, the nucleation rate at the sulphuric acid dominant sites could not be described with sulphuric acid concentration and a single value of the nucleation coefficient, as K in J=K [H2SO4]2, but the coefficients seemed to vary between the sites. This inter-site variation was substantially smaller when the heteromolecular homogenous nucleation between H2SO4 and organic vapours was assumed to take place in addition to homogenous nucleation of H2SO4 alone, i.e. J=KSA1 [H2SO4]2+KSA2 [H2SO4][org]. By adding in this equation a term describing homomolecular organic vapour nucleation, Ks3 [org]2, equally good results were achieved. In general, our results suggest that organic vapours do play a role, not only in the condensational growth of the particles, but as well in the nucleation process, with a site specific degree.

Download Full-text

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

Atmospheric Chemistry and Physics ◽

10.5194/acp-6-4079-2006 ◽

2006 ◽

Vol 6 (12) ◽

pp. 4079-4091 ◽

Cited By ~ 361

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.

Download Full-text

Aerosol dynamics simulations on the connection of sulphuric acid and new particle formation

Atmospheric Chemistry and Physics ◽

10.5194/acp-9-2933-2009 ◽

2009 ◽

Vol 9 (9) ◽

pp. 2933-2947 ◽

Cited By ~ 21

Author(s):

S.-L. Sihto ◽

H. Vuollekoski ◽

J. Leppä ◽

I. Riipinen ◽

V.-M. Kerminen ◽

...

Keyword(s):

Sulphuric Acid ◽

Acid Concentration ◽

Linear Dependence ◽

Particle Number ◽

Particle Formation ◽

Number Concentration ◽

Particle Number Concentration ◽

Aerosol Dynamics ◽

Sulphuric Acid Concentration ◽

Acid Dependence

Abstract. We have performed a series of simulations with an aerosol dynamics box model to study the connection between new particle formation and sulphuric acid concentration. For nucleation either activation mechanism with a linear dependence on the sulphuric acid concentration, kinetic mechanism with a squared dependence on the sulphuric acid concentration or ternary H2O-H2SO4-NH3 nucleation was assumed. The aim was to study the factors that affect the sulphuric acid dependence during the early stages of particle growth, and specifically to find conditions which would yield the linear dependence between the particle number concentration at 3–6 nm and sulphuric acid, as observed in field experiments. The simulations showed that the correlation with sulphuric acid may change during the growth from nucleation size to 3–6 nm size range, the main reason being the size dependent growth rate between 1 and 3 nm. In addition, the assumed size for the nucleated clusters had a crucial impact on the sulphuric acid dependence at 3 nm. A linear dependence between the particle number concentration at 3 nm and sulphuric acid was achieved, when activation nucleation mechanism was used with a low saturation vapour pressure for the condensable organic vapour, or with nucleation taking place at ~2 nm instead of ~1 nm. Simulations with activation, kinetic and ternary nucleation showed that ternary nucleation reproduces too steep dependence on sulphuric acid as compared to the linear or square dependence observed in field measurements.

Download Full-text

Measurement of iodine species and sulfuric acid using bromide chemical ionization mass spectrometers

10.5194/amt-2020-494 ◽

2020 ◽

Author(s):

Mingyi Wang ◽

Xu-Cheng He ◽

Henning Finkenzeller ◽

Siddharth Iyer ◽

Dexian Chen ◽

...

Keyword(s):

Sulfuric Acid ◽

Chemical Ionization ◽

Detection Limits ◽

Particle Formation ◽

Cloud Chamber ◽

Ionization Mass ◽

New Particle Formation ◽

Reduced Pressure ◽

Mass Spectrometers ◽

Iodine Species

Abstract. Iodine species are important in the marine atmosphere for oxidation and new-particle formation. Understanding iodine chemistry and iodine new-particle formation requires high time resolution, high sensitivity, and simultaneous measurements of many iodine species. Here, we describe the application of bromide chemical ionization mass spectrometers (Br-CIMS) to this task. During iodine new-particle formation experiments in the Cosmics Leaving OUtdoor Droplets (CLOUD) chamber, we have measured gas-phase iodine species and sulfuric acid using two Br-CIMS, one coupled to a Multi-scheme chemical IONization inlet (Br-MION-CIMS) and the other to a Filter Inlet for Gasses and AEROsols inlet (Br-FIGAERO-CIMS). From offline calibrations and inter-comparisons with other instruments attached to the CLOUD chamber, we have quantified the sensitivities of the Br-MION-CIMS to HOI, I2, and H2SO4 and obtain detection limits of 5.8 × 106, 6.3 × 105, and 2.0 × 105 molec cm−3, respectively, for a 2-min integration time. From binding energy calculations, we estimate the detection limit for HIO3 to be 1.2 × 105 molec cm−3, based on an assumption of maximum sensitivity. Detection limits in the Br-FIGAERO-CIMS are around one order of magnitude higher than those in the Br-MION-CIMS; for example, the detection limits for HOI and HIO3 are 3.3 × 107 and 5.1 × 106 molec cm−3, respectively. Our comparisons of the performance of the MION inlet and the FIGAERO inlet show that bromide chemical ionization mass spectrometers using either atmospheric pressure or reduced pressure interfaces are well-matched to measuring iodine species and sulfuric acid in marine environments.

Download Full-text

A statistical proxy for sulphuric acid concentration

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-11-20141-2011 ◽

2011 ◽

Vol 11 (7) ◽

pp. 20141-20179 ◽

Cited By ~ 1

Author(s):

S. Mikkonen ◽

S. Romakkaniemi ◽

J. N. Smith ◽

H. Korhonen ◽

T. Petäjä ◽

...

Keyword(s):

Solar Radiation ◽

Sulphuric Acid ◽

Acid Concentration ◽

Experimental Studies ◽

Global Solar Radiation ◽

Ionization Mass ◽

Sulphuric Acid Concentration ◽

So2 Concentration ◽

Condensation Sink

Abstract. Gaseous sulphuric acid is a key precursor for new particle formation in the atmosphere. Previous experimental studies have confirmed a strong correlation between the number concentrations of freshly formed particles and the ambient concentrations of sulphuric acid. This study evaluates a body of experimental gas phase sulphuric acid concentrations, as measured by Chemical Ionization Mass Spectrometry (CIMS) during six intensive measurement campaigns and one long-term observational period. The campaign datasets were measured in Hyytiälä, Finland, in 2003 and 2007, in San Pietro Capofiume, Italy, in 2009, in Melpitz, Germany, in 2008, in Atlanta, Georgia, USA, in 2002, and in Niwot Ridge, Colorado, USA, in 2007. The long term data were obtained in Hohenpeissenberg, Germany, during 1998 to 2000. The measured time series were used to construct proximity measures ("proxies") for sulphuric acid concentration by using statistical analysis methods. The objective of this study is to find a proxy for sulfuric acid that is valid in as many different atmospheric environments as possible. Our most accurate and universal formulation of the sulphuric acid concentration proxy uses global solar radiation, SO2 concentration, condensation sink and relative humidity as predictor variables, yielding a correlation measure (R) of 0.87 between observed concentration and the proxy predictions. Interestingly, the role of the condensation sink in the proxy was only minor, since similarly accurate proxies could be constructed with global solar radiation and SO2 concentration alone. This could be attributed to SO2 being an indicator for anthropogenic pollution, including particulate and gaseous emissions which represent sinks for the OH radical that, in turn, is needed for the formation of sulphuric acid.

Download Full-text