scholarly journals The SALTENA experiment: Comprehensive observations of aerosol sources, formation and processes in the South American Andes

2021 ◽  
pp. 1-46
Author(s):  
Federico Bianchi ◽  
Victoria A. Sinclair ◽  
Diego Aliaga ◽  
Qiaozhi Zha ◽  
Wiebke Scholz ◽  
...  
Keyword(s):  
High Altitude ◽  
Southern Hemisphere ◽  
Particle Formation ◽  
Particle Dispersion ◽  
Future Research ◽  
Formation Mechanisms ◽  
Particle Nucleation ◽  
New Particle Formation ◽  
La Paz ◽  
El Alto

AbstractThis paper presents an introduction to the Southern hemisphere high altitude experiment on particle nucleation and growth (SALTENA). This field campaign took place between December 2017 and June 2018 (wet to dry season) at Chacaltaya (CHC), a GAW (Global Atmosphere Watch) station located at 5240 m a.s.l. in the Bolivian Andes. Concurrent measurements were conducted at two additional sites in El Alto (4000 m a.s.l.) and La Paz (3600 m a.s.l.). The overall goal of the campaign was to identify the sources, understand the formation mechanisms and transport, and characterize the properties of aerosol at these stations. State-of-the-art instruments were brought to the station complementing the ongoing permanent GAW measurements, to allow a comprehensive description of the chemical species of anthropogenic and biogenic origin impacting the station and contributing to new particle formation. In this overview we first provide an assessment of the complex meteorology, air mass origin, and boundary layer – free troposphere interactions during the campaign using a 6-month high-resolution WRF (Weather Research and Forecasting) simulation coupled with FLEXPART (FLEXible PARTicle dispersion model). We then show some of the research highlights from the campaign, including i) chemical transformation processes of anthropogenic pollution while the air masses are transported to the CHC station from the metropolitan area of La Paz/El Alto, ii) volcanic emissions as an important source of atmospheric sulfur compounds in the region, iii) the characterization of the compounds involved in new particle formation, and iv) the identification of long-range transported compounds from the Pacific or the Amazon basin. We conclude the article with a presentation of future research foci. The SALTENA dataset highlights the importance of comprehensive observations in strategic high-altitude locations, especially the undersampled Southern Hemisphere.

scholarly journals New Particle Formation in the South Aegean Sea during the Etesians: importance for CCN production and cloud droplet number

2016 ◽  
Author(s):  
P. Kalkavouras ◽  
E. Bossioli ◽  
S. Bezantakos ◽  
A. Bougiatioti ◽  
N. Kalivitis ◽  
...  
Keyword(s):  
Water Vapor ◽  
Cloud Droplet ◽  
Aegean Sea ◽  
Particle Formation ◽  
Number Concentration ◽  
Cloud Formation ◽  
Particle Nucleation ◽  
New Particle Formation ◽  
Cloud Droplet Number Concentration ◽  
Measurement Period

Abstract. We examine the concentration levels and size distribution of submicron aerosol particles along with the concentration of trace gases and meteorological variables over the central (Santorini) and south Aegean Sea (Crete) from 15 to 28 July 2013, a period that includes Etesian events and moderate northern winds. Particle nucleation bursts were recorded during the Etesian flow at both stations, with those observed at Santorini reaching up to 1.5 × 104 particles cm−3. On Crete (at Finokalia station), the fraction of nucleation-mode particles was diminished, but a higher number of Aitken-mode was observed as a result of the downward mixing and photochemistry. Aerosol and photochemical pollutants covaried throughout the measurement period: lower concentrations were observed during the period of strong Etesian flow (e.g. 43–70 ppbv for ozone, 1.5–5.7 μg m−3 for sulfate), but were substantially enhanced during the period of moderate winds (i.e., increase of up to 32 % for ozone, and 140 % for sulfate). To understand how new particle formation (NPF) affects cloud formation, we quantify its impact on the CCN levels and cloud droplet number concentration. We find that NPF can double CCN number (at 0.1 % supersaturation) but the resulting strong competition for water vapor in cloudy updrafts decreases maximum supersaturation by 14 % and augments the potential droplet number only by 12 %. Therefore, although NPF events may strongly elevate CCN numbers, the relative impacts on cloud droplet number (compared to pre-event levels) is eventually limited by water vapor availability and depends on the prevailing cloud formation dynamics and the aerosol levels associated with the background in the region.

scholarly journals Modeling particle nucleation and growth over northern California during the 2010 CARES campaign

2015 ◽  
Vol 15 (21) ◽  
pp. 12283-12313 ◽  
Author(s):  
A. Lupascu ◽  
R. Easter ◽  
R. Zaveri ◽  
M. Shrivastava ◽  
M. Pekour ◽  
...  
Keyword(s):  
Size Distribution ◽  
Particle Number ◽  
Particle Formation ◽  
Number Concentration ◽  
Aerosol Size Distribution ◽  
Particle Nucleation ◽  
Particle Number Concentration ◽  
New Particle Formation ◽  
Organic Vapors ◽  
Diurnal Variability

Abstract. Accurate representation of the aerosol lifecycle requires adequate modeling of the particle number concentration and size distribution in addition to their mass, which is often the focus of aerosol modeling studies. This paper compares particle number concentrations and size distributions as predicted by three empirical nucleation parameterizations in the Weather Research and Forecast coupled with chemistry (WRF-Chem) regional model using 20 discrete size bins ranging from 1 nm to 10 μm. Two of the parameterizations are based on H2SO4, while one is based on both H2SO4 and organic vapors. Budget diagnostic terms for transport, dry deposition, emissions, condensational growth, nucleation, and coagulation of aerosol particles have been added to the model and are used to analyze the differences in how the new particle formation parameterizations influence the evolving aerosol size distribution. The simulations are evaluated using measurements collected at surface sites and from a research aircraft during the Carbonaceous Aerosol and Radiative Effects Study (CARES) conducted in the vicinity of Sacramento, California. While all three parameterizations captured the temporal variation of the size distribution during observed nucleation events as well as the spatial variability in aerosol number, all overestimated by up to a factor of 2.5 the total particle number concentration for particle diameters greater than 10 nm. Using the budget diagnostic terms, we demonstrate that the combined H2SO4 and low-volatility organic vapor parameterization leads to a different diurnal variability of new particle formation and growth to larger sizes compared to the parameterizations based on only H2SO4. At the CARES urban ground site, peak nucleation rates are predicted to occur around 12:00 Pacific (local) standard time (PST) for the H2SO4 parameterizations, whereas the highest rates were predicted at 08:00 and 16:00 PST when low-volatility organic gases are included in the parameterization. This can be explained by higher anthropogenic emissions of organic vapors at these times as well as lower boundary-layer heights that reduce vertical mixing. The higher nucleation rates in the H2SO4-organic parameterization at these times were largely offset by losses due to coagulation. Despite the different budget terms for ultrafine particles, the 10–40 nm diameter particle number concentrations from all three parameterizations increased from 10:00 to 14:00 PST and then decreased later in the afternoon, consistent with changes in the observed size and number distribution. We found that newly formed particles could explain up to 20–30 % of predicted cloud condensation nuclei at 0.5 % supersaturation, depending on location and the specific nucleation parameterization. A sensitivity simulation using 12 discrete size bins ranging from 1 nm to 10 μm diameter gave a reasonable estimate of particle number and size distribution compared to the 20 size bin simulation, while reducing the associated computational cost by ~ 36 %.

New particle formation events observed at a high altitude site Pico Espejo, Venezuela

2013 ◽  
Author(s):  
Tuomo Nieminen ◽  
Jenni Kontkanen ◽  
Radovan Krejci ◽  
Johan Ström ◽  
Peter Tunved ◽  
...  
Keyword(s):  
High Altitude ◽  
Particle Formation ◽  
New Particle Formation

New Particle Formation Involving Charged Sulfuric Acid – Ammonia Clusters

2020 ◽  
Author(s):  
Vitus Besel ◽  
Jakub Kubečka ◽  
Theo Kurtén ◽  
Hanna Vehkamäki
Keyword(s):  
Sulfuric Acid ◽  
Computational Study ◽  
Cluster Formation ◽  
Chem Phys ◽  
Particle Formation ◽  
Empirical Method ◽  
Particle Nucleation ◽  
New Particle Formation ◽  
Charged Clusters ◽  
Ammonia Clusters

<div> <p>The bulk of aerosol particles in the atmosphere are formed by gas-to-particle nucleation (Merikanto et al., 2009). However, the exact process of single molecules forming cluster, which subsequently can grow into particles, remains largely unknown. Recently, sulfuric acid has been identified to play a key role in this new particle formation enhanced by other compounds such as organic acids (Zhang, 2010) or ammonia (Anttila et al., 2005). To identify the characteristics of cluster formation and nucleation involving sulfuric acid and ammonia in neutral, positive and negative modes, we conducted a computational study. We used a layered approach for configurational sampling of the molecular clusters starting from utilizing a genetic algorithm in order to explore the whole potential energy surface (PES) with all plausible geometrical minima, however, with very unreliable energies. The structures were further optimized with a semi-empirical method and, then, at the ωB97X-D DFT level of theory. After each step, the optimized geometries were filtered to obtain the global minimum configuration. Further, a high level of theory (DLPNO-CCSD(T)) was used for obtaining the electronic energies, in addition to performing DFT frequency analysis, to calculate the Gibbs free energies of formation. These were passed to the Atmospheric Cluster Dynamics Code (ACDC) (McGrath et al., 2012) for studying the evolution of cluster populations. We determined the global minima for the following sulfuric acid - ammonia clusters: (H<sub>2</sub>SO<sub>4</sub>)<sub>m</sub>(NH<sub>3</sub>)<sub>n</sub> with m=n, m=n+1 and n=m+1 for neutral clusters, (H<sub>2</sub>SO<sub>4</sub>)<sub>m</sub>(HSO<sub>4</sub>)<sup>−</sup>(NH<sub>3</sub>)<sub>n</sub> with m=n and n=m+1 for positively charged clusters, and (H<sub>2</sub>SO<sub>4</sub>)<sub>m</sub>(NH<sub>4</sub>)<sup>+</sup>(NH<sub>3</sub>)<sub>n</sub> with m=n and m=n+1 for negatively charged clusters. Further, we present the formation rates, steady state concentrations and fluxes of these clusters calculated using ACDC and discuss how a new configurational sampling procedure, more precise quantum chemistry methods and parameters, such as symmetry and a quasiharmonic approach, impact these ACDC results in comparison to previous studies.</p> </div><div> <p><em>References:<br></em><em>J. Merikanto, D. V. Spracklen, G. W. Mann, S. J. Pickering, and K. S. Carslaw (2009). Atmos. Chem.  Phys., 9, 8601-8616. <br>R. Zhang (2010). Science, 328, 1366-1367. <br>T. Anttila, H. Vehkamäki, I. Napari, M. Kulmala (2005). Boreal Env. Res., 10, 523. <br>M.J. McGrath, T. Olenius, I.K. Ortega, V. Loukonen, P.  Paasonen, T. Kurten, M. Kulmala (2012). Atmos. Chem. Phys., 12, 2355. <br></em></p> </div>

Evidence of new particle formation during post monsoon season over a high-altitude site of the Western Ghats, India

2017 ◽  
Vol 99 (4) ◽  
pp. 652-664 ◽  
Author(s):  
Parakkatt Parambil Leena ◽  
Vasudevan Anil Kumar ◽  
Kundan. K. Dani ◽  
Sunil. M. Sombawne ◽  
Palani Murugavel ◽  
...  
Keyword(s):  
High Altitude ◽  
Western Ghats ◽  
Monsoon Season ◽  
Particle Formation ◽  
New Particle Formation ◽  
Post Monsoon ◽  
Post Monsoon Season ◽  
The Western Ghats

scholarly journals Contribution of new particle formation to the total aerosol concentration at the high-altitude site Jungfraujoch (3580 m asl, Switzerland)

2016 ◽  
Vol 121 (19) ◽  
pp. 11,692-11,711 ◽  
Author(s):  
Jasmin Tröstl ◽  
Erik Herrmann ◽  
Carla Frege ◽  
Federico Bianchi ◽  
Ugo Molteni ◽  
...  
Keyword(s):  
High Altitude ◽  
Particle Formation ◽  
Aerosol Concentration ◽  
New Particle Formation

scholarly journals New particle formation from the oxidation of direct emissions of pine seedlings

2009 ◽  
Vol 9 (2) ◽  
pp. 8223-8260 ◽  
Author(s):  
L. Q. Hao ◽  
P. Yli-Pirilä ◽  
P. Tiitta ◽  
S. Romakkaniemi ◽  
P. Vaattovaara ◽  
...  
Keyword(s):  
Scots Pine ◽  
Formation Rate ◽  
Particle Formation ◽  
Effective Density ◽  
Particle Nucleation ◽  
New Particle Formation ◽  
Aerosol Mass Spectrometer ◽  
Aerosol Mass ◽  
Pine Seedlings ◽  
Condensational Growth

Abstract. Measurements of particle formation following the gas phase oxidation of volatile organic compounds (VOCs) emitted by Scots pine (Pinus sylvestris L.) seedlings are reported. Particle nucleation and condensational growth both from ozone (O3) and hydroxyl radical (OH) initiated oxidation of pine emissions (about 20–120 ppb) were investigated in a~smog chamber. During experiments, tetramethylethylene (TME) and 2-butanol were added to control the concentrations of O3 and OH. Particle nucleation and condensational growth rates were interpreted with a chemical kinetics model. Scots pine emissions mainly included α-pinene, β-pinene, Δ3-carene, limonene, myrcene, β-phellandrene and isoprene, composing more than 95% of total emissions. Modeled OH concentration in the O3+OH induced experiments was at a level of ~106 molecular cm−3. Our results demonstrate that OH-initiated oxidation of VOCs plays an important role in the nucleation process during the initial new particle formation stage. The highest average nucleation rate of 360 cm−3 s−1 was observed for the OH-dominated nucleation events and the lowest aerosol mean formation rate less than 0.5 cm−3 s−1 for the case with only O3 present as an oxidant. On the other hand, ozonolysis of monoterpenes appears to be much more efficient to the aerosol growth process following nucleation. Higher contributions of more oxygenated products to the SOA mass loadings from OH-dominating oxidation systems were found as compared to the ozonolysis systems. Comparison of mass and volume distributions from the aerosol mass spectrometer and differential mobility analyzer yields estimated effective density of these SOA to be 1.34±0.06 g cm−3 with the OH plus O3 initiated oxidation systems and 1.38±0.03 g cm−3 with the ozonolysis dominated chemistry.

scholarly journals New particle formation and ultrafine charged aerosol climatology at a high altitude site in the Alps (Jungfraujoch, 3580 m a.s.l., Switzerland)

2010 ◽  
Vol 10 (4) ◽  
pp. 11361-11399 ◽  
Author(s):  
J. Boulon ◽  
K. Sellegri ◽  
H. Venzac ◽  
D. Picard ◽  
E. Weingartner ◽  
...  
Keyword(s):  
High Altitude ◽  
Particle Formation ◽  
Swiss Alps ◽  
Aerosol Size Distribution ◽  
New Particle Formation ◽  
High Concentration ◽  
Air Masses ◽  
Charged Aerosol ◽  
Smog Chambers ◽  
The Many

Abstract. Aerosol nucleation is an important source of atmospheric particles which have an effect both on the climatic system and on human health. The new particle formation (NPF) process is an ubiquitous phenomenon, yet poorly understood despite the many studies performed on this topic using various approaches (observation, experimentation in smog chambers and modeling). In this work, we investigate the formation of secondary charged aerosols and its climatology at Jungfraujoch, a high altitude site in Swiss Alps (3580 m a.s.l.). Charged particles and clusters (0.5–1.8 nm) were measured within the EUCAARI program from April 2008 to April 2009 and allowed the detection of nucleation events. We found that the aerosol concentration, which is dominated by cluster size class, shows a strong diurnal pattern and that the aerosol size distribution and concentration are strongly influenced by the presence of clouds either during daytime or nighttime conditions. New particle formation events have been investigated and it appears that new particle formation occurs 17.5% of measured days and that the nucleation frequency is strongly linked to air mass origin and path and negatively influenced by cloud presence. In fact, we show that NPF events depend on the occurrence of high concentration VOCs air masses which allowed clusters growing by condensation of organic vapors rather than nucleation of new clusters. Furthermore, the contribution of ions to nucleation process was studied and we found that ion-mediated nucleation (IMN) contribute to 26% of the total nucleation so that ions play an important role in the new particle formation and growth at Jungfraujoch.

scholarly journals New particle formation from sulfuric acid and ammonia: nucleation and growth model based on thermodynamics derived from CLOUD measurements for a wide range of conditions

2019 ◽  
Author(s):  
Andreas Kürten
Keyword(s):  
Sulfuric Acid ◽  
Growth Model ◽  
Thermodynamic Data ◽  
Particle Formation ◽  
Nucleation And Growth ◽  
Aerosol Size Distribution ◽  
Formation Mechanisms ◽  
Strong Impact ◽  
New Particle Formation ◽  
Wide Range

Abstract. Understanding new particle formation and growth is important because of the strong impact of these processes on climate and air quality. Measurements to elucidate the main new particle formation mechanisms are essential; however, these mechanisms have to be implemented in models to estimate their impact on the regional and global scale. Parameterizations are computationally cheap ways of implementing nucleation schemes in models but they have their limitations, as they do not necessarily include all relevant parameters. Process models using sophisticated nucleation schemes can be useful for the generation of look-up tables in large-scale models or for the analysis of individual new particle formation events. In addition, some other important properties can be derived from a process model that implicitly calculates the evolution of the full aerosol size distribution, e.g., the particle growth rates. Within this study, a model (SANTIAGO, Sulfuric acid Ammonia NucleaTIon And GrOwth model) is constructed that simulates new particle formation starting from the monomer of sulfuric acid up to a particle size of several hundred nanometers. The smallest sulfuric acid clusters containing one to four acid molecules and varying amount of base (ammonia) are allowed to evaporate in the model, whereas growth beyond the pentamer (5 sulfuric acid molecules) is assumed to be entirely collision-controlled. The main goal of the present study is to derive appropriate thermodynamic data needed to calculate the cluster evaporation rates as a function of temperature. These data are derived numerically from CLOUD (Cosmics Leaving OUtdoor Droplets) chamber new particle formation rates for neutral sulfuric acid-water-ammonia nucleation at temperatures between 208 K and 292 K. The numeric methods include an optimization scheme to derive the best estimates for the thermodynamic data (dH and dS) and a Monte Carlo method to derive their probability density functions. The derived data are compared to literature values. Using different data sets for dH and dS in SANTIAGO detailed comparison between model results and measured CLOUD new particle formation rates is discussed.

scholarly journals Long-term observations of positive cluster ion concentration, sources and sinks at the high altitude site of the Puy de Dôme

2013 ◽  
Vol 13 (6) ◽  
pp. 14927-14975 ◽  
Author(s):  
C. Rose ◽  
J. Boulon ◽  
M. Hervo ◽  
H. Holmgren ◽  
E. Asmi ◽  
...  
Keyword(s):  
Steady State ◽  
High Altitude ◽  
Balance Equation ◽  
Ionization Rate ◽  
Particle Formation ◽  
Ion Concentration ◽  
Cluster Ions ◽  
New Particle Formation ◽  
Cluster Ion ◽  
Ionization Rates

Abstract. Cluster particles (0.8–1.9 nm) are key entities involved in nucleation and new particle formation processes in the atmosphere. Cluster ions were characterized in clear sky conditions at the Puy de Dôme station (1465 m a.s.l). The studied dataset spread over five years (February 2007–February 2012), which provided a unique chance to catch seasonal variations of cluster ion properties at high altitude. Statistical values of the cluster ion concentration and diameter are reported for both positive and negative polarities. Cluster ions were found to be ubiquitous at the Puy de Dôme and displayed an annual variation with lower concentrations in spring. Positive cluster ions were less numerous than negative ones but were larger in diameters. Negative cluster ion properties seemed insensitive to the occurrence of a new particle formation (NPF) event while positive cluster ions appeared to be significantly more numerous and larger on event days. The parameters of the balance equation for the positive cluster concentration are reported, separately for the different seasons and for the NPF event days and non-event days. The steady state assumption suggests that the ionization rate is balanced with two sinks which are the ion recombination and the attachment on aerosol particles, referred as "aerosol ion sink". The aerosol ion sink was found to be higher during the warm season and dominated the loss of ions. The positive ionization rates derived from the balance equation were well correlated with the ionization rates obtained from radon measurement, and they were on average higher in summer and fall compared to winter and spring. Neither the aerosol ion sink nor the ionization rate were found to be significantly different on event days compared to non-event days, and thus they were not able to explain the different positive cluster concentrations between event and non-event days. Hence, the excess of positive small ions on event days may derive from an additional source of ions coupled with the fact that the steady state was not verified on event days.

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