scholarly journals Ternary homogeneous nucleation of H<sub>2</sub>SO<sub>4</sub>, NH<sub>3</sub>, and H<sub>2</sub>O under conditions relevant to the lower troposphere

2010 ◽  
Vol 10 (9) ◽  
pp. 22395-22414 ◽  
Author(s):  
D. Benson ◽  
A. Markovich ◽  
S.-H. Lee
Keyword(s):  
Nucleation Rate ◽  
Homogeneous Nucleation ◽  
Enhancement Factor ◽  
Lower Troposphere ◽  
Global Scale ◽  
Particle Formation ◽  
New Particle Formation ◽  
Aerosol Formation ◽  
Laboratory Measurements ◽  
Atmospheric Observations

Abstract. Ternary homogeneous nucleation (THN) of H2SO4, NH3 and H2O has been used to explain new particle formation in various atmospheric regions, yet laboratory measurements have failed to reproduce atmospheric observations. Here, we report laboratory observations of THN made under conditions relevant to the lower troposphere (H2SO4 of 106–107 cm−3, NH3 of 0.08–20 ppbv, and 288 K). Our observations show that NH3 can enhance atmospheric H2SO4 aerosol nucleation and the enhancement factor (EF) in nucleation rate due to NH3 increases linearly with increasing NH3 and increases exponentially with decreasing H2SO4 and RH. The critical clusters of ternary homogeneous nucleation contain 3–5 molecules of H2SO4, 1–4 molecules of H2O, and only 1 molecule of NH3. The composition of H2SO4 and H2O in critical clusters and the threshold of H2SO4 concentrations required for the unit nucleation rate both do not vary in the presence and absence of NH3. These observations can be directly used to improve aerosol nucleation models to correctly assess how man-made SO2 and NH3 affect aerosol formation and CCN production at the global scale.

scholarly journals Ternary homogeneous nucleation of H<sub>2</sub>SO<sub>4</sub>, NH<sub>3</sub>, and H<sub>2</sub>O under conditions relevant to the lower troposphere

2011 ◽  
Vol 11 (10) ◽  
pp. 4755-4766 ◽  
Author(s):  
D. R. Benson ◽  
J. H. Yu ◽  
A. Markovich ◽  
S.-H. Lee
Keyword(s):  
Homogeneous Nucleation ◽  
Chemical Ionization ◽  
Lower Troposphere ◽  
Global Scale ◽  
Ionization Mass ◽  
Aerosol Formation ◽  
Laboratory Measurements ◽  
Mass Spectrometers ◽  
Water Condensation ◽  
Atmospheric Observations

Abstract. Ternary homogeneous nucleation (THN) of H2SO4, NH3 and H2O has been used to explain new particle formation in various atmospheric regions, yet laboratory measurements of THN have failed to reproduce atmospheric observations. Here, we report first laboratory observations of THN made under conditions relevant to the lower troposphere ([H2SO4] of 106–107 cm−3, [NH3] of 0.08–20 ppbv, and a temperature of 288 K). Our observations show that NH3 can enhance atmospheric H2SO4 aerosol nucleation and the enhancement factor (EF) in nucleation rate (J) due to NH3 (the ratio of J measured with vs. without NH3) increases linearly with increasing [NH3] and increases with decreasing [H2SO4] and RH. Two chemical ionization mass spectrometers (CIMS) are used to measure [H2SO4] and [NH3], as well as possible impurities of amines in the nucleation system. Aerosol number concentrations are measured with a water condensation counter (CPC, TSI 3786). The slopes of Log J vs. Log [H2SO4], Log J vs. Log RH, and Log J vs. Log [NH3] are 3–5, 1–4, and 1, respectively. These slopes and the threshold of [H2SO4] required for the unity nucleation vary only fractionally in the presence and absence of NH3. These observations can be used to improve aerosol nucleation models to assess how man-made SO2 and NH3 affect aerosol formation and CCN production at the global scale.

scholarly journals First comprehensive modelling study on observed new particle formation at the SORPES station in Nanjing, China

2015 ◽  
Vol 15 (19) ◽  
pp. 27501-27538 ◽  
Author(s):  
X. Huang ◽  
L. X. Zhou ◽  
A. J. Ding ◽  
X. M. Qi ◽  
W. Nie ◽  
...  
Keyword(s):  
Transport Model ◽  
Anthropogenic Activities ◽  
Lower Troposphere ◽  
Particle Formation ◽  
Oxidation Products ◽  
New Particle Formation ◽  
Aerosol Formation ◽  
The Yrd ◽  
Modelling System ◽  
Modelling Study

Abstract. New particle formation (NPF) has been investigated intensively during the last two decades because of its influence on aerosol population and the possible contribution to cloud condensation nuclei. However, intensive measurements and modelling activities on this topic in urban metropolitans in China with frequently high pollution episodes are still very limited. This study provides results from a comprehensive modelling study on the occurrence of new particle formation events in the western part of the Yangtze River Delta region (YRD), China. The comprehensive modelling system, which combines regional chemical transport model WRF-Chem (the Weather Research and Forecasting model coupled with Chemistry) and the sectional box model MALTE-BOX (the model to predict new aerosol formation in the lower troposphere), was shown to be capable of simulating atmospheric nucleation and subsequent growth. Here we present a detailed discussion of three typical NPF days, during which the measured air masses were notably influenced by either anthropogenic activities, biogenic emissions, or mixed ocean and continental sources. Overall, simulated NPF events were generally in good agreement with the corresponding measurements, enabling us to get further insights into NPF processes in the YRD region. Based on the simulations, we conclude that besides gas-phase sulphuric acid, biogenic organic compounds, particularly monoterpenes, play an essential role in condensational growth of newly formed clusters and probably also in the particle formation process through their low volatile oxidation products. Although some uncertainties remain in this modelling system, this method provides a possibility to better understand the NPF processes.

scholarly journals Comprehensive modelling study on observed new particle formation at the SORPES station in Nanjing, China

2016 ◽  
Vol 16 (4) ◽  
pp. 2477-2492 ◽  
Author(s):  
Xin Huang ◽  
Luxi Zhou ◽  
Aijun Ding ◽  
Ximeng Qi ◽  
Wei Nie ◽  
...  
Keyword(s):  
Transport Model ◽  
Anthropogenic Activities ◽  
Lower Troposphere ◽  
Particle Formation ◽  
Oxidation Products ◽  
New Particle Formation ◽  
Aerosol Formation ◽  
The Yrd ◽  
Modelling System ◽  
Modelling Study

Abstract. New particle formation (NPF) has been investigated intensively during the last 2 decades because of its influence on aerosol population and the possible contribution to cloud condensation nuclei. However, intensive measurements and modelling activities on this topic in urban metropolitan areas in China with frequent high-pollution episodes are still very limited. This study provides results from a comprehensive modelling study on the occurrence of NPF events in the western part of the Yangtze River Delta (YRD) region, China. The comprehensive modelling system, which combines the WRF-Chem (the Weather Research and Forecasting model coupled with Chemistry) regional chemical transport model and the MALTE-BOX sectional box model (the model to predict new aerosol formation in the lower troposphere), was shown to be capable of simulating atmospheric nucleation and subsequent growth. Here we present a detailed discussion of three typical NPF days, during which the measured air masses were notably influenced by either anthropogenic activities, biogenic emissions, or mixed ocean and continental sources. Overall, simulated NPF events were generally in good agreement with the corresponding measurements, enabling us to get further insights into NPF processes in the YRD region. Based on the simulations, we conclude that biogenic organic compounds, particularly monoterpenes, play an essential role in the initial condensational growth of newly formed clusters through their low-volatility oxidation products. Although some uncertainties remain in this modelling system, this method provides a possibility to better understand particle formation and growth processes.

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.

Studying new particle formation from chemical emissions from sea surface using  ship-borne air-sea-interaction tanks

2021 ◽  
Author(s):  
Maija Peltola ◽  
Manon Rocco ◽  
Neill Barr ◽  
Erin Dunne ◽  
James Harnwell ◽  
...  
Keyword(s):  
Marine Biology ◽  
Cloud Condensation Nuclei ◽  
Aerosol Particles ◽  
Chemical Species ◽  
Particle Formation ◽  
Biological Properties ◽  
The European Union ◽  
New Particle Formation ◽  
Aerosol Formation ◽  
Horizon 2020

&lt;p&gt;Even though oceans cover over 70% of the Earth&amp;#8217;s surface, the ways in which oceans interact with climate are not fully known. Marine micro-organisms such as phytoplankton can play an important role in regulating climate by releasing different chemical species into air. In air these chemical species can react and form new aerosol particles. If grown to large enough sizes, aerosols can influence climate by acting as cloud condensation nuclei which influence the formation and properties of clouds. Even though a connection of marine biology and climate through aerosol formation was first proposed already over 30 years ago, the processes related to this connection are still uncertain.&lt;/p&gt;&lt;p&gt;To unravel how seawater properties affect aerosol formation and to identify which chemical species are responsible for aerosol formation, we built two Air-Sea-Interaction Tanks (ASIT) that isolate 1000 l of seawater and 1000 l of air directly above the water. The used seawater was collected from different locations during a ship campaign on board the R/V Tangaroa in the South West Pacific Ocean, close to Chatham Rise, east of New Zealand. Seawater from one location was kept in the tanks for 2-3 days and then changed. By using seawater collected from different locations, we could obtain water with different biological populations. To monitor the seawater, we took daily samples to determine its chemical and biological properties.&lt;/p&gt;&lt;p&gt;The air in the tanks was continuously flushed with particle filtered air. This way the air had on average 40 min to interact with the seawater surface before being sampled. Our air sampling was continuous and consisted of aerosol and air chemistry measurements. The instrumentation included measurements of aerosol number concentration from 1 to 500 nm and&amp;#160; chemical species ranging from ozone and sulphur dioxide to volatile organic compounds and chemical composition of molecular clusters.&lt;/p&gt;&lt;p&gt;Joining the seawater and atmospheric data together can give us an idea of what chemical species are emitted from the water into the atmosphere and whether these species can form new aerosol particles. Our preliminary results show a small number of particles in the freshly nucleated size range of 1-3 nm in the ASIT headspaces, indicating that new aerosol particles can form in the ASIT headspaces. In this presentation, we will also explore which chemical species could be responsible for aerosol formation and which plankton groups could be related to the emissions of these species. Combining these results with ambient data and modelling work can shed light on how important new particle formation from marine sources is for climate.&lt;/p&gt;&lt;p&gt;Acknowledgements: Sea2Cloud project is funded by European Research Council (ERC) under the European Union&amp;#8217;s Horizon 2020 research and innovation programme (Grant agreement No. 771369).&lt;/p&gt;

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.

scholarly journals Cold oceans enhance terrestrial new-particle formation in near-coastal forests

2009 ◽  
Vol 9 (22) ◽  
pp. 8639-8650 ◽  
Author(s):  
T. Suni ◽  
L. Sogacheva ◽  
J. Lauros ◽  
H. Hakola ◽  
J. Bäck ◽  
...  
Keyword(s):  
Radiative Forcing ◽  
Vegetation Index ◽  
Climate Models ◽  
Particle Formation ◽  
New Particle Formation ◽  
Aerosol Formation ◽  
Coastal Forests ◽  
Organic Precursor ◽  
North East ◽  
The North

Abstract. The world's forests produce atmospheric aerosol by emitting volatile organic compounds (VOC) which, after being oxidized in the atmosphere, readily condense on the omnipresent nanometer-sized nuclei and grow them to climatically relevant sizes. The cooling effect of aerosols is the greatest uncertainty in current climate models and estimates of radiative forcing. Therefore, identifying the environmental factors influencing the biogenic formation of aerosols is crucial. In this paper, we connected biogenic aerosol formation events observed in a Eucalypt forest in South-East Australia during July 2005–December 2006 to air mass history using 96-h back trajectories. Formation of new particles was most frequent in the dry westerly and south-westerly air masses. According to NDVI (Normalized Difference Vegetation Index) measurements, photosynthesis was not significantly higher in this direction compared to the north-east direction. It is unlikely, therefore, that differences in photosynthesis-derived organic precursor emissions would have been significant enough to lead to the clear difference in NPF frequency between these two directions. Instead, the high evaporation rates above the Pacific Ocean resulted in humid winds from the north-east that effectively suppressed new-particle formation in the forest hundreds of kilometers inland. No other factor varied as significantly in tune with new-particle formation as humidity and we concluded that, in addition to local meteorological factors in the forest, the magnitude of evaporation from oceans hundreds of kilometers upwind can effectively suppress or enhance new-particle formation. Our findings indicate that, unlike warm waters, the cold polar oceans provide excellent clean and dry background air that enhances aerosol formation above near-coastal forests in Fennoscandia and South-East Australia.

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).

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