scholarly journals Sulfuric acid and OH concentrations in a boreal forest site

2009 ◽  
Vol 9 (19) ◽  
pp. 7435-7448 ◽  
Author(s):  
T. Petäjä ◽  
R. L. Mauldin, III ◽  
E. Kosciuch ◽  
J. McGrath ◽  
T. Nieminen ◽  
...  
Keyword(s):  
Sulfuric Acid ◽  
Gas Phase ◽  
Acid Concentration ◽  
Sulfuric Acid Concentration ◽  
Particle Formation ◽  
Daily Maximum ◽  
Ionization Mass ◽  
Forest Site ◽  
Aerosol Formation ◽  
Atmospheric Particle

Abstract. As demonstrated in a number of investigations, gaseous sulfuric acid plays a central role in atmospheric aerosol formation. Using chemical ionization mass spectrometer the gas-phase sulfuric acid and OH concentration were measured in Hyytiälä, SMEAR II station, Southern Finland during 24 March to 28 June 2007. Clear diurnal cycles were observed as well as differences between new particle formation event days and non-event days. Typically, the daily maximum concentrations of gas phase sulfuric acid varied from 3×105 to 2×106 molec cm−3 between non-event and event days. Noon-time OH concentrations varied from 3-6×105 molec cm−3 and not a clear difference between event and non-events was detected. The measured time series were also used as a foundation to develop reasonable proxies for sulfuric acid concentration. The proxies utilized source and sink terms, and the simplest proxy is radiation times sulfur dioxide divided by condensation sink. Since it is still challenging to measure sulfuric acid in ambient concentrations, and due to its significant role in atmospheric particle formation, reasonable proxies are needed. We use all together three different proxies and one chemical box model and compared their results to the measured data. The proxies for the sulfuric acid concentration worked reasonably well, and will be used to describe sulfuric acid concentrations in SMEAR II station, when no measured sulfuric acid data is available. With caution the proxies could be applied to other environments as well.

scholarly journals Sulfuric acid and OH concentrations in a boreal forest site

2008 ◽  
Vol 8 (6) ◽  
pp. 20193-20221
Author(s):  
T. Petäjä ◽  
R. L. Mauldin, III ◽  
E. Kosciuch ◽  
J. McGrath ◽  
T. Nieminen ◽  
...  
Keyword(s):  
Sulfuric Acid ◽  
Gas Phase ◽  
Sulfuric Acid Concentration ◽  
Particle Formation ◽  
Daily Maximum ◽  
Ionization Mass ◽  
Forest Site ◽  
Aerosol Formation ◽  
Atmospheric Particle ◽  
Diurnal Cycles

Abstract. As demonstrated in a number of investigations, gaseous sulfuric acid plays a central role in atmospheric aerosol formation. Using chemical ionization mass spectrometer the gas-phase sulfuric acid and OH concentration were measured in Hyytiälä, SMEAR II station, Southern Finland during 24 March to 28 June 2007. Clear diurnal cycles were observed as well as differences between new particle formation event days and non-event days. The typical daily maximum concentrations of gas phase sulfuric acid varied from 3·105 to 2·106 molec cm−3 between non-event and event days. Noon-time OH concentrations varied from 3–6·105 molec cm−3 and not a clear difference between event and non-events was detected. Since it is still challenging to measure sulfuric acid, and due to its significant role in atmospheric particle formation, three different proxies and one chemical box model calculation were compared to the measured data. The proxies for the sulfuric acid concentration worked reasonably, and with caution, could be applied to other environments.

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

2011 ◽  
Vol 11 (11) ◽  
pp. 5277-5287 ◽  
Author(s):  
D. Brus ◽  
K. Neitola ◽  
A.-P. Hyvärinen ◽  
T. Petäjä ◽  
J. Vanhanen ◽  
...  
Keyword(s):  
Sulfuric Acid ◽  
Gas Phase ◽  
Acid Concentration ◽  
High Efficiency ◽  
Detection Efficiency ◽  
Sulfuric Acid Concentration ◽  
Ionization Mass ◽  
Atmospheric Measurements ◽  
Flow Tube ◽  
Particle Counter

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 108 to 3 × 109 molecules cm−3. The nucleation rates obtained in this study cover about three orders of magnitude from 10−1 to 102 cm−3 s−1 for commercial ultrafine condensation particle counter (UCPC) TSI model 3025A and from 101 to 104 cm−3 s−1 for PSM. The nucleation rates and the slopes (dlnJ/dln [H2SO4]) 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 cut-off-size of 1.5 nm together with direct measurements of gas phase sulfuric acid concentration.

scholarly journals Aerosol surface area concentration: a governing factor in new particle formation in Beijing

2017 ◽  
Vol 17 (20) ◽  
pp. 12327-12340 ◽  
Author(s):  
Runlong Cai ◽  
Dongsen Yang ◽  
Yueyun Fu ◽  
Xing Wang ◽  
Xiaoxiao Li ◽  
...  
Keyword(s):  
Sulfuric Acid ◽  
Surface Area ◽  
Acid Concentration ◽  
Mass Concentration ◽  
Sulfuric Acid Concentration ◽  
Particle Formation ◽  
Geometric Standard Deviation ◽  
Daily Maximum ◽  
Growth Enhancement ◽  
New Particle Formation

Abstract. The predominating role of aerosol Fuchs surface area, AFuchs, in determining the occurrence of new particle formation (NPF) events in Beijing was elucidated in this study. The analysis was based on a field campaign from 12 March to 6 April 2016 in Beijing, during which aerosol size distributions down to  ∼  1 nm and sulfuric acid concentrations were simultaneously monitored. The 26 days were classified into 11 typical NPF days, 2 undefined days, and 13 non-event days. A dimensionless factor, LΓ, characterized by the relative ratio of the coagulation scavenging rate over the condensational growth rate (Kuang et al., 2010), was applied in this work to reveal the governing factors for NPF events in Beijing. The three parameters determining LΓ are sulfuric acid concentration, the growth enhancement factor characterized by contribution of other gaseous precursors to particle growth, Γ, and AFuchs. Different from other atmospheric environments, such as in Boulder and Hyytiälä, the daily-maximum sulfuric acid concentration and Γ in Beijing varied in a narrow range with geometric standard deviations of 1.40 and 1.31, respectively. A positive correlation between the estimated new particle formation rate, J1.5, and sulfuric acid concentration was found with a mean fitted exponent of 2.4. However, the maximum sulfuric acid concentrations on NPF days were not significantly higher (even lower, sometimes) than those on non-event days, indicating that the abundance of sulfuric acid in Beijing was high enough to initiate nucleation, but may not necessarily lead to NPF events. Instead, AFuchs in Beijing varied greatly among days with a geometric standard deviation of 2.56, whereas the variabilities of AFuchs in Tecamac, Atlanta, and Boulder were reported to be much smaller. In addition, there was a good correlation between AFuchs and LΓ in Beijing (R2 = 0.88). Therefore, it was AFuchs that fundamentally determined the occurrence of NPF events. Among 11 observed NPF events, 10 events occurred when AFuchs was smaller than 200 µm2 cm−3. NPF events were suppressed due to the coagulation scavenging when AFuchs was greater than 200 µm2 cm−3. Measured AFuchs in Beijing had a good correlation with its PM2.5 mass concentration (R2 = 0.85) since AFuchs in Beijing was mainly determined by particles in the size range of 50–500 nm that also contribute to the PM2.5 mass concentration.

scholarly journals The simulations of sulfuric acid concentration and new particle formation in an urban atmosphere in China

2013 ◽  
Vol 13 (6) ◽  
pp. 14977-15005
Author(s):  
Z. B. Wang ◽  
M. Hu ◽  
D. Mogensen ◽  
D. L. Yue ◽  
J. Zheng ◽  
...  
Keyword(s):  
Sulfuric Acid ◽  
Acid Concentration ◽  
Sulfuric Acid Concentration ◽  
Lower Troposphere ◽  
Particle Formation ◽  
Urban Atmosphere ◽  
Chemical Mechanism ◽  
New Particle Formation ◽  
Aerosol Formation ◽  
Surrounding Areas

Abstract. Simulations of sulfuric acid concentration and new particle formation are performed by using the zero-dimensional version of the model MALTE (Model to predict new Aerosol formation in the Lower TropospherE) and measurements from the Campaign of Air Quality Research in Beijing and Surrounding areas (CAREBeijing) in 2008. Chemical reactions from the Master Chemical Mechanism Version 3.2 (MCM v3.2) are used in the model. High correlation (slope = 0.72, R = 0.74) between the modelled and observed sulfuric acid concentrations is found during daytime (06:00–18:00). The aerosol dynamics are simulated by the University of Helsinki Multicomponent Aerosol (UHMA) model including several nucleation mechanisms. The results indicate that the model is able to predict the on- and offset of new particle formation in an urban atmosphere in China. In addition, the number concentrations of newly formed particles in kinetic-type nucleation including homogenous homomolecular (J=K[H2SO4]2) and homogenous heteromolecular nucleation involving organic vapours (J=Khet[H2SO4][Org]) are in satisfactory agreement with the observations. However, the specific organic compounds possibly participate in the nucleation process should be investigated in further studies.

scholarly journals The simulations of sulfuric acid concentration and new particle formation in an urban atmosphere in China

2013 ◽  
Vol 13 (21) ◽  
pp. 11157-11167 ◽  
Author(s):  
Z. B. Wang ◽  
M. Hu ◽  
D. Mogensen ◽  
D. L. Yue ◽  
J. Zheng ◽  
...  
Keyword(s):  
Sulfuric Acid ◽  
Acid Concentration ◽  
Sulfuric Acid Concentration ◽  
Lower Troposphere ◽  
Particle Growth ◽  
Particle Formation ◽  
Urban Atmosphere ◽  
Chemical Mechanism ◽  
New Particle Formation ◽  
Aerosol Formation

Abstract. Simulations of sulfuric acid concentration and new particle formation are performed by using the zero-dimensional version of the model MALTE (Model to predict new Aerosol formation in the Lower TropospherE) and measurements from the Campaign of Air Quality Research in Beijing and Surrounding areas (CAREBeijing) in 2008. Chemical reactions from the Master Chemical Mechanism version 3.2 (MCM v3.2) are used in the model. High correlation (slope = 0.72, R = 0.74) between the modelled and observed sulfuric acid concentrations is found during daytime (06:00–18:00). The aerosol dynamics are simulated by the University of Helsinki Multicomponent Aerosol (UHMA) model including several nucleation mechanisms. The results indicate that the model is able to predict the on- and offset of new particle formation in an urban atmosphere in China. In addition, the number concentrations of newly formed particles in kinetic-type nucleation including homogenous homomolecular (J=K[H2SO4]2) and homogenous heteromolecular nucleation involving organic vapours (J=Khet[H2SO4][Org]) are in satisfactory agreement with the observations. However, the specific organic compounds that possibly participate in the nucleation process should be investigated in further studies. For the particle growth, only a small fraction of the oxidized total organics condense onto the particles in polluted environments. Meanwhile, the OH and O3 oxidation mechanism contribute 5.5% and 94.5% to the volume concentration of small particles, indicating the particle growth is more controlled by the precursor gases and their oxidation by O3.

scholarly journals Aerosol Surface Area Concentration: a Governing Factor for New Particle Formation in Beijing

2017 ◽  
Author(s):  
Runlong Cai ◽  
Dongsen Yang ◽  
Yueyun Fu ◽  
Xing Wang ◽  
Xiaoxiao Li ◽  
...  
Keyword(s):  
Sulfuric Acid ◽  
Surface Area ◽  
Acid Concentration ◽  
Mass Concentration ◽  
Sulfuric Acid Concentration ◽  
Particle Formation ◽  
Atmospheric Environment ◽  
Geometric Standard Deviation ◽  
Growth Enhancement ◽  
New Particle Formation

Abstract. The predominating role of aerosol Fuchs surface area, AFuchs, in determining the occurrence of new particle formation (NPF) events in Beijing was elucidated in this study. Analysis was based on a field campaign from March 12th to April 6th, 2016, in Beijing, during which aerosol size distributions down to ~ 1 nm and sulfuric acid concentration were simultaneously monitored. The 26 days were classified into 11 typical NPF days, 2 undefined days, and 13 non-event days. A dimensionless factor, LΓ, characterizing the relative ratio of the coagulation scavenging rate over the condensational growth rate and predicting whether or not a NPF event would occur (Kuang et al., 2010), was applied. The three parameters determining LΓ are sulfuric acid concentration, the growth enhancement factor characterizing contribution of other gaseous precursors to particle growth, Γ, and AFuchs. Different from other atmospheric environment such as in Boulder and Hyytiälä, the variations of daily maximum sulfuric acid concentration and Γ in Beijing are in a narrow range with geometric standard deviations of 1.40 and 1.31, respectively. Positive correlation was found between estimated new particle formation rate, J1.5, and sulfuric acid concentration with a mean fitted exponent of 2.4. However, sulfuric acid concentration on NPF days is not significantly higher than that on non-event days. Instead, AFuchs varies greatly among days in Beijing with a geometric standard deviation of 2.56, while it is relatively stable at other locations such as Tecamac, Atlanta, and Boulder. Good correlation was found between AFuchs and LΓ in Beijing (R2 = 0.88). It appears that the abundance of gaseous precursors such as sulfuric acid in Beijing is high enough to have nucleation, however, it is AFuchs that determines the occurrence of NPF event in Beijing. 10 in 11 NPF events occurred when AFuchs is smaller than 200 μm2/cm3, and the NPF event was suppressed due to coagulation scavenging when AFuchs is larger than 200 μm2/cm3. Measured AFuchs is in good correlation with PM2.5 mass concentration (R2 = 0.85) since AFuchs in Beijing is mainly determined by particles in the size range of 50–500 nm that also contribute to PM2.5 mass concentration.

scholarly journals Contribution of sulfuric acid and oxidized organic compounds to particle formation and growth

2012 ◽  
Vol 12 (5) ◽  
pp. 11351-11389 ◽  
Author(s):  
F. Riccobono ◽  
L. Rondo ◽  
M. Sipilä ◽  
P. Barmet ◽  
J. Curtius ◽  
...  
Keyword(s):  
Growth Rate ◽  
Sulfuric Acid ◽  
Organic Compounds ◽  
Growth Rates ◽  
Strong Dependence ◽  
Sulfuric Acid Concentration ◽  
Particle Growth ◽  
Particle Formation ◽  
Ionization Mass ◽  
Organic Vapors

Abstract. Lack of knowledge about the mechanisms underlying new particle formation and their subsequent growth is one of the main causes for the large uncertainty in estimating the radiative forcing of atmospheric aerosols in global models. We performed chamber experiments designed to study the contributions of sulfuric acid and organic vapors to formation and to the early growth of nucleated particles, respectively. Distinct experiments in the presence of two different organic precursors (1,3,5-trimethylbenzene and α-pinene) showed the ability of these compounds to reproduce the formation rates observed in the low troposphere. These results were obtained measuring the sulfuric acid concentrations with two Chemical Ionization Mass Spectrometers confirming the results of a previous study which modeled the sulfuric acid concentrations in presence of 1,3,5-trimethylbenzene. New analysis methods were applied to the data collected with a Condensation Particle Counter battery and a Scanning Mobility Particle Sizer, allowing the assessment of the size resolved growth rates of freshly nucleated particles. The effect of organic vapors on particle growth was investigated by means of the growth rate enhancement factor (Γ), defined as the ratio between the measured growth rate in the presence of α-pinene and the kinetically limited growth rate of the sulfuric acid and water system. The observed Γ values indicate that the growth is dominated by organic compounds already at particle diameters of 2 nm. Both the absolute growth rates and Γ showed a strong dependence on particle size supporting the nano-Köhler theory. Moreover, the separation of the contributions from sulfuric acid and organic compounds to particles growth reveals that the organic contribution seems to be enhanced by the sulfuric acid concentration. The size resolved growth analysis finally indicates that both condensation of oxidized organic compounds and reactive uptake contribute to particle growth.

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

2014 ◽  
Vol 7 (11) ◽  
pp. 3849-3859 ◽  
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.

scholarly journals Applying the CPCB setup to study the hygroscopicity and composition of freshly-formed 2–9 nm particles in boreal forest

2008 ◽  
Vol 8 (4) ◽  
pp. 14893-14925 ◽  
Author(s):  
I. Riipinen ◽  
H. E. Manninen ◽  
T. Yli-Juuti ◽  
M. Boy ◽  
M. Sipilä ◽  
...  
Keyword(s):  
Boreal Forest ◽  
Particle Growth ◽  
Particle Formation ◽  
Water Soluble ◽  
Forest Site ◽  
Relative Role ◽  
Aerosol Formation ◽  
Climatic Effects ◽  
Secondary Aerosol ◽  
Atmospheric Particle

Abstract. Measurements on the composition of nanometer-sized atmospheric particles are the key to understand which vapors participate in the secondary aerosol formation processes. Knowledge on these processes is crucial in assessing the climatic effects of secondary aerosol formation. We present data of >2 nm particle concentrations and their hygroscopicity measured with the Condensation Particle Counter Battery (CPCB) at a boreal forest site in Hyytiälä, Finland, during spring 2006. This is the first time such results on the hygroscopicity and composition of the freshly formed atmospheric clusters as small as 2 nm have been reported – bringing us closer to online measurements of the compounds participating in atmospheric particle formation. The data reveal that during new particle formation events, the smallest particles activate for growth at clearly smaller sizes in water than in butanol vapor. However, even at 2–4 nm, the particles are less hygroscopic than ammonium sulfate or sulfuric acid, which are often referred to as the most likely compounds present in atmospheric nucleation. This observation points to the presence of water-soluble organics, even at the very first steps on particle formation. The water-affinity of the particles decreases with size, indicating that the vapors that participate in the first steps of the particle formation and growth are more hygroscopic than the vapors contributing to the later stages of the growth. This suggests that the relative role of less hygroscopic organics in atmospheric particle growth increases as a function of particle size.

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