The influence of volcano activity on aerosol formation over the Andes

Author(s):  
Federico Bianchi ◽  
Diego Aliaga ◽  
Qiaozhi Zha ◽  
Liine Heikkinen ◽  
Marcos Andrade ◽  
...  

<p>A significant fraction (>50%) of cloud condensation nuclei (CCN) in the atmosphere arises from new particle formation (Dunne et al., 2016). While particle nucleation has been observed almost everywhere in the atmosphere, the mechanisms governing this process are still poorly understood and subject of on-going research. For example, it is still largely unknown which components participate in new-particle formation. Laboratory experiments and quantum chemical calculations have identified potential candidates that may play a role, including sulphuric acid, ions, ammonia, amines and highly oxygenated organic molecules (Kirkby et al., 2011; Almeida et al., 2013; Bianchi et al., 2016; Bianchi et al., 2019).</p><p>Here we present observations of the formation and growth of newly formed particles measured during intense volcano activities.</p><p>The measurements were conducted at Chacaltaya mountain station (5240 m a.s.l.) in Bolivia. The station is located on top of the Cordillera Real. It has air masses coming from the Amazon forest, La Paz and the Bolivian altiplano.</p><p>With the Chemical Ionization Atmospheric Pressure interface Time-Of-Light mass spectrometers (CI-APi-TOF) we measured H<sub>2</sub>SO<sub>4</sub>, the APi-TOF retrieved the chemical composition of positive and negative ions. Ion and particle size distributions were measured with the NAIS (Neutral cluster and Air Ion Spectrometer) and the SMPS (Scanning Mobility Particle Sizer), respectively. The PSM (Particle Sizer Magnifier) measured particles with a cut off that varied from 1-4 nm. Finally, with the ACSM (Aerosol Chemical Speciation Monitor) and the FIGAERO (Filter Inlet for Gases and AEROsols) we retrieved the aerosol chemical composition. Besides this set of instruments, other parameters were measured at the Chacaltaya GAW station.</p><p>During the intensive measurement campaign, air masses coming directly from volcano eruptions were detected by all our instruments. We were therefore able to determine the gas and particle chemical composition of the air mass. In addition to that, we observed several NPF events triggered by air masses coming from volcanic emissions. With this set of instruments, we were able to retrieve the chemical composition of the vapours leading to the formation of new particles. It was found that all the nucleation event observed during the volcano activity were triggered by sulphuric acid and ammonia. In the presentation we will show more details on the chemical and physical mechanism behind this process.</p><p> </p><p>Almeida, J., et al., (2013) Nature 502, 359-363.</p><p>Bianchi, F., et al., (2016) Science 6289, 1109-1112.</p><p>Bianchi, F., et al., (2019) Chemical Review 119, 3472−3509</p><p>Dunne et al., (2016) Science 354, 1119-1124.</p><p>Kirkby, J., et al., (2011) Nature 476, (7361), 429-433.</p>

2008 ◽  
Vol 8 (22) ◽  
pp. 6729-6738 ◽  
Author(s):  
N. Kalivitis ◽  
W. Birmili ◽  
M. Stock ◽  
B. Wehner ◽  
A. Massling ◽  
...  

Abstract. Atmospheric particle size distributions were measured on Crete island, Greece in the Eastern Mediterranean during an intensive field campaign between 28 August and 20 October, 2005. Our instrumentation combined a differential mobility particle sizer (DMPS) and an aerodynamic particle sizer (APS) and measured number size distributions in the size range 0.018 μm–10 μm. Four time periods with distinct aerosol characteristics were discriminated, two corresponding to marine and polluted air masses, respectively. In marine air, the sub-μm size distributions showed two particle modes centered at 67 nm and 195 nm having total number concentrations between 900 and 2000 cm−3. In polluted air masses, the size distributions were mainly unimodal with a mode typically centered at 140 nm, with number concentrations varying between 1800 and 2900 cm−3. Super-μm particles showed number concentrations in the range from 0.01 to 2.5 cm−3 without any clear relation to air mass origin. A small number of short-lived particle nucleation events were recorded, where the calculated particle formation rates ranged between 1.1–1.7 cm−3 s−1. However, no particle nucleation and growth events comparable to those typical for the continental boundary layer were observed. Particles concentrations (Diameter <50 nm) were low compared to continental boundary layer conditions with an average concentration of 300 cm−3. The production of sulfuric acid and its subsequently condensation on preexisting particles was examined with the use of a simplistic box model. These calculations suggested that the day-time evolution of the Aitken particle population was governed mainly by coagulation and that particle formation was absent during most days.


2008 ◽  
Vol 8 (2) ◽  
pp. 6571-6601
Author(s):  
N. Kalivitis ◽  
W. Birmili ◽  
M. Stock ◽  
B. Wehner ◽  
A. Massling ◽  
...  

Abstract. Atmospheric particle size distributions were measured on Crete island, Greece in the Eastern Mediterranean during an intensive field campaign between 28 August and 20 October 2005. Our instrumentation combined a differential mobility particle sizer (DMPS) and an aerodynamic particle sizer (APS) and measured number size distributions in the size range 0.018 μm–10 μm. Four time periods with distinct aerosol characteristics were discriminated, two corresponding to marine and polluted air masses, respectively. In marine air, the sub-μm size distributions showed two particle modes centered at 67 nm and 195 nm having total number concentrations between 900 and 2000 cm−3. In polluted air masses, the size distributions were mainly unimodal with a mode typically centered at 140 nm, with number concentrations varying between 1800 and 2900 cm−3. Super-μm particles showed number concentrations in the range from 0.01 to 2.5 cm−3 without any clear relation to air mass origin. A small number of short-lived particle nucleation events were recorded, where the calculated particle formation rates ranged between 1.1–1.7 cm−3 s−1. However, no particle nucleation and growth events comparable to those typical for the continental boundary layer were observed. Particles concentrations (Diameter <50 nm) were low compared to continental boundary layer conditions with an average concentration of 300 cm−3. The production of sulfuric acid and its subsequently condensation on preexisting particles was examined with the use of a simplistic box model. These calculations suggested that the day-time evolution of the Aitken particle population was governed mainly by coagulation and that particle formation was absent during most days.


2020 ◽  
Vol 20 (10) ◽  
pp. 5911-5922 ◽  
Author(s):  
Hing Cho Cheung ◽  
Charles Chung-Kuang Chou ◽  
Celine Siu Lan Lee ◽  
Wei-Chen Kuo ◽  
Shuenn-Chin Chang

Abstract. The chemical composition of fine particulate matter (PM2.5), the size distribution and number concentration of aerosol particles (NCN), and the number concentration of cloud condensation nuclei (NCCN) were measured at the northern tip of Taiwan during an intensive observation experiment from April 2017 to March 2018. The parameters of aerosol hygroscopicity (i.e., activation ratio, activation diameter and kappa of CCN) were retrieved from the measurements. Significant variations were found in the hygroscopicity of aerosols (kappa – κ – of 0.18–0.56, for water vapor supersaturation – SS – of 0.12 %–0.80 %), which were subject to various pollution sources, including aged air pollutants originating in eastern and northern China and transported by the Asian continental outflows and fresh particles emitted from local sources and distributed by land–sea breeze circulations as well as produced by processes of new particle formation (NPF). Cluster analysis was applied to the back trajectories of air masses to investigate their respective source regions. The results showed that aerosols associated with Asian continental outflows were characterized by lower NCN and NCCN values and by higher kappa values of CCN, whereas higher NCN and NCCN values with lower kappa values of CCN were observed in the aerosols associated with local air masses. Besides, it was revealed that the kappa value of CCN exhibited a decrease during the early stage of an event of new particle formation, which turned to an increasing trend over the later period. The distinct features in the hygroscopicity of aerosols were found to be consistent with the characteristics in the chemical composition of PM2.5. This study has depicted a clear seasonal characteristic of hygroscopicity and CCN activity under the influence of a complex mixture of pollutants from different regional and/or local pollution sources. Nevertheless, the mixing state and chemical composition of the aerosols critically influence the aerosol hygroscopicity, and further investigations are necessary to elucidate the atmospheric processing involved in the CCN activation in coastal areas.


2019 ◽  
Author(s):  
Hing Cho Cheung ◽  
Charles C.-K. Chou ◽  
Celine S. L. Lee ◽  
Wei-Chen Kuo ◽  
Shuenn-Chin Chang

Abstract. The chemical composition of fine particulate matters (PM2.5), the size distribution and number concentration of aerosol particles (NCN) and the number concentration of cloud condensation nuclei (NCCN) were measured at the northern tip of Taiwan Island during a campaign from April 2017 to March 2018. The parameters of aerosol hygroscopicity (i.e. activation ratio, activation diameter and kappa) were retrieved from the measurements. Significant variations were found in the hygroscopicity of aerosols, which were suggested be subject to various pollution sources, including aged air pollutants originating in the eastern/northern China and transported on the Asian continental outflows, fresh particles emitted from local sources and distributed by land-sea breeze circulations as well as produced by new particle formation (NPF) processes. Cluster analysis was applied to the backward trajectories of air masses to investigate their respective source regions. The results showed that the aerosols associated with Asian continental outflows were characterized with higher kappa values, whereas higher NCCN and NCN with lower kappa values were found for aerosols in local air masses. The distinct features in hygroscopicity were consistent with the characteristics in the chemical composition of PM2.5. Moreover, this study revealed that the nucleation mode particles from NPF could have participated in the enhancement of CCN activity, most likely by coagulating with sub-CCN particles, although the freshly produced particles were not favored for CCN activation due to their smaller sizes. Thus, the results of this study suggested that the NPF coupling with coagulation processes can significantly increase the NCCN in atmosphere.


2013 ◽  
Vol 13 (24) ◽  
pp. 12495-12506 ◽  
Author(s):  
Z. B. Wang ◽  
M. Hu ◽  
J. Y. Sun ◽  
Z. J. Wu ◽  
D. L. Yue ◽  
...  

Abstract. Long-term measurements of particle number size distributions were carried out both at an urban background site (Peking University, PKU) and a regional Global Atmospheric Watch station (Shangdianzi, SDZ) from March to November in 2008. In total, 52 new particle formation (NPF) events were observed simultaneously at both sites, indicating that this is a regional phenomenon in the North China Plain. On average, the mean condensation sink value before the nucleation events started was 0.025 s−1 in the urban environment, which was 1.6 times higher than that at regional site. However, higher particle formation and growth rates were observed at PKU (10.8 cm−3 s−1 and 5.2 nm h−1) compared with those at SDZ (4.9 cm−3 s−1 and 4.0 nm h−1). These results implied that precursors were much more abundant in the polluted urban environment. Different from the observations in cleaner environments, the background conditions of the observed particle homogeneous nucleation events in the North China Plain could be characterized as the co-existing of a stronger source of precursor gases and a higher condensational sink of pre-existing aerosol particles. Secondary aerosol formation following nucleation events results in an increase of particle mass concentration, particle light scattering coefficient, and cloud condensation nuclei (CCN) number concentration, with consequences on visibility, radiative effects, and air quality. Typical regional NPF events with significant particle nucleation rates and subsequent particle growth over a sufficiently long time period at both sites were chosen to investigate the influence of NPF on the number concentration of "potential" CCN. As a result, the NPF and the subsequent condensable growth increased the CCN number concentration in the North China Plain by factors in the range from 5.6 to 8.7. Moreover, the potential contribution of anthropogenic emissions to the CCN number concentration was more than 50%, to which more attention should be drawn in regional and global climate modeling, especially in the polluted urban areas.


2013 ◽  
Vol 13 (4) ◽  
pp. 9401-9442 ◽  
Author(s):  
R. Väänänen ◽  
E.-M. Kyrö ◽  
T. Nieminen ◽  
N. Kivekäs ◽  
H. Junninen ◽  
...  

Abstract. We investigated atmospheric aerosol particle dynamics in a boreal forest zone in Northern Scandinavia. We used aerosol size distribution data measured with either a Differential Mobility Particle Sizer (DMPS) or Scanning Mobility Particle Sizer (SMPS) at three stations (Värriö, Pallas and Abisko), and combined these data with the HYSPLIT air mass trajectory analysis. We compared three approaches: analysis of new particle formation events, investigation of air masses transport from the ocean to individual stations with different over-land transport times, and analysis of changes in aerosol particle size distributions during the air masses transport from one measurement station to another. Aitken mode particles were found to have an apparent average growth rate of 0.6–0.7 nm h−1 when the air masses travelled over land. Particle growth rates during the NPF events were 3–6 times higher than the apparent particle growth. When comparing aerosol dynamics between the different stations for different over-land transport times, no major differences were found except that in Abisko the new particle formation events were observed to take place in air masses having shorter over-land times than at the other stations. We speculate that this is related to the meteorological differences along the paths of air masses caused by the land surface topology. When comparing between air masses travelling the east-to-west direction to those traveling the west-to-east directions, clear differences in the aerosol dynamics were seen. Our results suggest that the condensation growth has an important role in aerosol dynamics also when new particle formation is not evident.


2006 ◽  
Vol 6 (12) ◽  
pp. 4079-4091 ◽  
Author(s):  
S.-L. Sihto ◽  
M. Kulmala ◽  
V.-M. Kerminen ◽  
M. Dal Maso ◽  
T. Petäjä ◽  
...  

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.


2016 ◽  
Author(s):  
P. Kalkavouras ◽  
E. Bossioli ◽  
S. Bezantakos ◽  
A. Bougiatioti ◽  
N. Kalivitis ◽  
...  

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.


2015 ◽  
Vol 15 (21) ◽  
pp. 12283-12313 ◽  
Author(s):  
A. Lupascu ◽  
R. Easter ◽  
R. Zaveri ◽  
M. Shrivastava ◽  
M. Pekour ◽  
...  

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 %.


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