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

2012 ◽  
Vol 12 (19) ◽  
pp. 9113-9133 ◽  
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).

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

2012 ◽  
Vol 12 (5) ◽  
pp. 11485-11537 ◽  
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).

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

2010 ◽  
Vol 10 (22) ◽  
pp. 11223-11242 ◽  
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.

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

2010 ◽  
Vol 10 (5) ◽  
pp. 11795-11850 ◽  
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.

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

2014 ◽  
Vol 7 (7) ◽  
pp. 6595-6624
Author(s):  
L. Rondo ◽  
A. Kürten ◽  
S. Ehrhart ◽  
S. Schobesberger ◽  
A. Franchin ◽  
...  
Keyword(s):  
Sulphuric Acid ◽  
Mass Spectrometer ◽  
Acid Concentration ◽  
Particle Formation ◽  
Galactic Cosmic Rays ◽  
Cloud Chamber ◽  
Proton Synchrotron ◽  
Ionization Mass ◽  
New Particle Formation ◽  
Sulphuric Acid Concentration

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.

scholarly journals Why formation rate of 3 nm particles depends linearly on sulphuric acid concentration?

2005 ◽  
Vol 5 (6) ◽  
pp. 11277-11293 ◽  
Author(s):  
M. Kulmala ◽  
K. E. J. Lehtinen ◽  
A. Laaksonen
Keyword(s):  
Sulphuric Acid ◽  
Acid Concentration ◽  
Formation Rate ◽  
Activation Process ◽  
Activation Theory ◽  
Atmospheric Observations ◽  
Nucleation Theorem ◽  
Condensing Agents ◽  
Heterogeneous Chemical Reactions ◽  
Sulphuric Acid Concentration

Abstract. According to atmospheric observations new particle formation seems to be a function of sulphuric acid concentration to the power from one to two. The nucleation theorem then predicts that the critical cluster contains one to two sulphuric acid molecules. However, existing nucleation theories predicts that the power is more (or equal) than 2. Here we present an activation theory, which can explain the observed slope. In cluster activation the clusters containing one sulphuric acid molecule will activate for further growth due to heterogeneous nucleation, heterogeneous chemical reactions including polymerization or activation of soluble clusters. In the activation process organic vapours are typically needed as condensing agents.

scholarly journals Cluster activation theory as an explanation of the linear dependence between formation rate of 3nm particles and sulphuric acid concentration

2006 ◽  
Vol 6 (3) ◽  
pp. 787-793 ◽  
Author(s):  
M. Kulmala ◽  
K. E. J. Lehtinen ◽  
A. Laaksonen
Keyword(s):  
Sulphuric Acid ◽  
Acid Concentration ◽  
Formation Rate ◽  
Activation Process ◽  
Activation Theory ◽  
Atmospheric Observations ◽  
Nucleation Theorem ◽  
Condensing Agents ◽  
Heterogeneous Chemical Reactions ◽  
Sulphuric Acid Concentration

Abstract. According to atmospheric observations new particle formation seems to be a function of sulphuric acid concentration to the power from one to two. The nucleation theorem then predicts that the critical cluster contains one to two sulphuric acid molecules. However, existing nucleation theories predicts that the power is more (or equal) than 2. Here we present an activation theory, which can explain the observed slope. In cluster activation the clusters containing one sulphuric acid molecule will activate for further growth due to heterogeneous nucleation, heterogeneous chemical reactions including polymerization or activation of soluble clusters. In the activation process organic vapours are typically needed as condensing agents.

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

2009 ◽  
Vol 9 (9) ◽  
pp. 2933-2947 ◽  
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.

Kinetics of sulfuric acid-amine nucleation in the urban atmospheric environment

2020 ◽  
Author(s):  
Runlong Cai ◽  
Chao Yan ◽  
Jun Zheng ◽  
Lin Wang ◽  
Markku Kulmala ◽  
...  
Keyword(s):  
Reaction Kinetics ◽  
Urban Environment ◽  
Formation Rate ◽  
Particle Formation ◽  
Atmospheric Environment ◽  
Atmospheric Conditions ◽  
Laboratory Studies ◽  
New Particle Formation ◽  
The Real ◽  
Real Atmosphere

<p>The formation of new secondary aerosols form gaseous precursors is a frequent phenomenon in various atmospheric environments and it impacts aerosol number concentration, cloud formation, and hence climate. There has been a considerable number of new particle formation (NPF) studies in various atmospheric environments, but current knowledge on NPF in the polluted atmospheric boundary layer (e.g., the urban environment in megacities) is still limited. The clustering of H<sub>2</sub>SO<sub>4</sub> and amines is a possible mechanism driving the fast nucleation and initial growth of new particles in the polluted urban environment. Laboratory studies using typical ambient H<sub>2</sub>SO<sub>4</sub> concentrations and theoretical calculations based on quantum chemistry have provided insights into H<sub>2</sub>SO<sub>4</sub>-amine nucleation. However, the molecular-level mechanism and governing factors for H<sub>2</sub>SO<sub>4</sub>-amine nucleation have not been quantitatively investigated in the real atmosphere. Some previous studies indicate that differently from clean environments, the coagulation scavenging is a governing factor for NPF in polluted environments. In the presence of a high aerosol concentration in the polluted environment, a considerable fraction of the newly formed particles are scavenged by coagulation within minutes and hence, NPF is significantly suppressed. Similarly, the coagulation scavenging may also impact the steady-state cluster concentrations and the new particle formation rate. Due to the differences in the coagulation scavenging and perhaps some gaseous precursor concentrations between laboratory and atmospheric conditions, the reaction kinetics determined in previous laboratory studies may not directly applicable to the real atmosphere. Herein, based on long-term atmospheric measurements from January 2018 to March 2019 in urban Beijing, we show the different reaction kinetics under laboratory and atmospheric conditions and how to unify them using proper normalization approaches. The influences of governing factors on particle formation rate are then quantitatively elucidated. Based on the synergistic effects of these factors, an indicator for the occurrence of NPF in the urban environment is proposed and verified.</p>

scholarly journals The charging of neutral dimethylamine and dimethylamine-sulphuric acid clusters using protonated acetone

2014 ◽  
Vol 7 (11) ◽  
pp. 11011-11044
Author(s):  
K. Ruusuvuori ◽  
P. Hietala ◽  
O. Kupiainen-Määttä ◽  
T. Jokinen ◽  
H. Junninen ◽  
...  
Keyword(s):  
Sulphuric Acid ◽  
Chemical Ionization ◽  
Lower Troposphere ◽  
Particle Formation ◽  
Atmospheric Conditions ◽  
Atmospheric Particle ◽  
Organic Bases ◽  
Atmospheric Nucleation ◽  
Quantum Chemical Methods ◽  
Vapour Concentration

Abstract. Sulphuric acid is generally considered one of the most important substances taking part in atmospheric particle formation. However, in typical atmospheric conditions in the lower troposphere sulphuric acid and water alone are unable to form particles. It has been suggested that strong bases may stabilize sulphuric acid clusters so that particle formation may occur. More to the point, amines – strong organic bases – have become the subject of interest as possible cause for such stabilisation. To probe whether amines play a role in atmospheric nucleation, we need to be able to measure accurately the gas-phase amine vapour concentration. Such measurements often include charging the neutral molecules and molecular clusters in the sample. Since amines are bases, the charging process should introduce a positive charge. This can be achieved for example using a positively charged reagent with a suitable proton affinity. In our study, we have used quantum chemical methods combined with a cluster dynamics code to study the use of acetone as a reagent in chemical ionization and compared the results with measurements performed with a chemical ionization atmospheric pressure interface time-of-flight mass spectrometer (CI-APi-TOF). The computational results indicate that protonated acetone is an effective reagent in chemical ionization. However, in the experiments the charger ions were not depleted at the predicted dimethylamine concentrations, indicating that either the modelling scheme or the experimental results – or both – contain unidentified sources of error.

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