1. A European aerosol phenomenology - 9 : light absorption properties of carbonaceous aerosol particles across surface EuropeJordi Rovira, Marjan Savadkoohi, Gang I. Chen, Griša Močnik, Wenche Aas, Lucas Alados-Arboledas, B. Artíñano, Asta Gregorič, Matic Ivančič, Jesús Yus-Díez, 2024, original scientific article Abstract: Carbonaceous aerosols (CA), composed of black carbon (BC) and organic matter (OM), significantly impact the climate. Light absorption properties of CA, particularly of BC and brown carbon (BrC), are crucial due to their contribution to global and regional warming. We present the absorption properties of BC (bAbs,BC) and BrC (bAbs,BrC) inferred using Aethalometer data from 44 European sites covering different environments (traffic (TR), urban (UB), suburban (SUB), regional background (RB) and mountain (M)). Absorption coefficients showed a clear relationship with station setting decreasing as follows: TR > UB > SUB > RB > M, with exceptions. The contribution of bAbs,BrC to total absorption (bAbs), i.e. %AbsBrC, was lower at traffic sites (11–20 %), exceeding 30 % at some SUB and RB sites. Low AAE values were observed at TR sites, due to the dominance of internal combustion emissions, and at some remote RB/M sites, likely due to the lack of proximity to BrC sources, insufficient secondary processes generating BrC or the effect of photobleaching during transport. Higher bAbs and AAE were observed in Central/Eastern Europe compared to Western/Northern Europe, due to higher coal and biomass burning emissions in the east. Seasonal analysis showed increased bAbs, bAbs,BC, bAbs,BrC in winter, with stronger %AbsBrC, leading to higher AAE. Diel cycles of bAbs,BC peaked during morning and evening rush hours, whereas bAbs,BrC, %AbsBrC, AAE, and AAEBrC peaked at night when emissions from household activities accumulated. Decade-long trends analyses demonstrated a decrease in bAbs, due to reduction of BC emissions, while bAbs,BrC and AAE increased, suggesting a shift in CA composition, with a relative increase in BrC over BC. This study provides a unique dataset to assess the BrC effects on climate and confirms that BrC can contribute significantly to UV–VIS radiation presenting highly variable absorption properties in Europe.
Keywords: aerosol absorption, black carbon, brown carbon, climate change, air pollution
Published in RUNG: 10.12.2024; Views: 310; Downloads: 4
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2. Probing Iceland's dust-emitting sediments: : particle size distribution, mineralogy, cohesion, Fe mode of occurrence, and reflectance spectra signaturesAdolfo Gonzalez-Romero, Cristina González-Flórez, Agnesh Panta, Jesús Yus-Díez, Patricia Córdoba, Andrés Alastuey, Natalia Moreno, Konrad Kandler, Martina Klose, Roger N. Clark, 2024, original scientific article Abstract: Abstract. Characterising the physico-chemical properties of dust-emitting sediments in arid regions is fundamental to understanding the effects of dust on climate and ecosystems. However, knowledge regarding high-latitude dust (HLD) remains limited. This study focuses on analysing the particle size distribution (PSD), mineralogy, cohesion, iron (Fe) mode of occurrence, and visible–near infrared (VNIR) reflectance spectra of dust-emitting sediments from dust hotspots in Iceland (HLD region). Extensive analysis was conducted on samples of top sediments, sediments, and aeolian ripples collected from seven dust sources, with particular emphasis on the Jökulsá basin, encompassing the desert of Dyngjunsandur. Both fully and minimally dispersed PSDs and their respective mass median particle diameters revealed remarkable similarities (56 ± 69 and 55 ± 62 µm, respectively). Mineralogical analyses indicated the prevalence of amorphous phases (68 ± 26 %), feldspars (17 ± 13 %), and pyroxenes (9.3 ± 7.2 %), consistent with thorough analyses of VNIR reflectance spectra. The Fe content reached 9.5 ± 0.40 wt %, predominantly within silicate structures (80 ± 6.3 %), complemented by magnetite (16 ± 5.5 %), hematite/goethite (4.5 ± 2.7 %), and readily exchangeable Fe ions or Fe nano-oxides (1.6 ± 0.63 %). Icelandic top sediments exhibited coarser PSDs compared to the high dust-emitting crusts from mid-latitude arid regions, distinctive mineralogy, and a 3-fold bulk Fe content, with a significant presence of magnetite. The congruence between fully and minimally dispersed PSDs underscores reduced particle aggregation and cohesion of Icelandic top sediments, suggesting that aerodynamic entrainment of dust could also play a role upon emission in this region, alongside saltation bombardment. The extensive analysis in Dyngjusandur enabled the development of a conceptual model to encapsulate Iceland's rapidly evolving high dust-emitting environments.
Keywords: mineral dust, high-latitude dust, Icelandic dust, aerosol particles
Published in RUNG: 29.11.2024; Views: 320; Downloads: 1
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3. Atmospheric black carbon in the metropolitan area of La Paz and El Alto, Bolivia: concentration levels and emission sourcesValeria Mardoñez-Balderrama, Griša Močnik, Marco Pandolfi, Robin L. Modini, Fernando Velarde, Laura Renzi, Angela Marinoni, Jean-Luc Jaffrezo, Isabel Moreno R., Diego Aliaga, 2024, original scientific article Abstract: Abstract. Black carbon (BC) is a major component of submicron particulate matter (PM), with significant health and climate impacts. Many cities in emerging countries lack comprehensive knowledge about BC emissions and exposure levels. This study investigates BC concentration levels, identifies its emission sources, and characterizes the optical properties of BC at urban background sites of the two largest high-altitude Bolivian cities: La Paz (LP) (3600 m above sea level) and El Alto (EA) (4050 m a.s.l.), where atmospheric oxygen levels and intense radiation may affect BC production. The study relies on concurrent measurements of equivalent black carbon (eBC), elemental carbon (EC), and refractory black carbon (rBC) and their comparison with analogous data collected at the nearby Chacaltaya Global Atmosphere Watch Station (5240 m a.s.l). The performance of two independent source apportionment techniques was compared: a bilinear model and a least-squares multilinear regression (MLR). Maximum eBC concentrations were observed during the local dry season (LP: eBC = 1.5 ± 1.6 µg m−3; EA: 1.9±2.0 µg m−3). While eBC concentrations are lower at the mountain station, daily transport from urban areas is evident. Average mass absorption cross sections of 6.6–8.2 m2 g−1 were found in the urban area at 637 nm. Both source apportionment methods exhibited a reasonable level of agreement in the contribution of biomass burning (BB) to absorption. The MLR method allowed the estimation of the contribution and the source-specific optical properties for multiple sources, including open waste burning.
Keywords: black carbon, aerosol absorption, source apportionment, mass absorption cross-section
Published in RUNG: 29.10.2024; Views: 492; Downloads: 0
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4. Across Mediterranean experiment for the Cal/Val of the EarthCARE missionEleni Marinou, Vassilis Amiridis, Peristera Paschou, Alexandra Tsekeri, Ioanna Tsikoudi, Voudouri Kaliopi-Artemis, Anna Gialitaki, Maria Tsichla, Kyriaki Papachristopoulou, Griša Močnik, 2024, published scientific conference contribution Keywords: EarthCARE, Saharan dust, validation, aerosol, airborne measurements
Published in RUNG: 09.09.2024; Views: 673; Downloads: 4
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5. Dust, convection, winds and waves : the 2022 NASA CPEX-CV campaignEdward P. Nowottnick, Angela K. Rowe, Amin R. Nehrir, Jonathan A. Zawislak, Aaron J. Piña, Will McCarty, Rory A. Barton-Grimley, Kristopher M. Bedka, J. Ryan Bennett, Griša Močnik, 2024, original scientific article Abstract: The NASA Convective Processes Experiment - Cabo Verde (CPEX-CV) field campaign took place in September 2022 out of Sal Island, Cabo Verde. A unique payload aboard the NASA DC-8 aircraft equipped with advanced remote sensing and in situ instrumentation, in conjunction with radiosonde launches and satellite observations, allowed CPEX-CV to target the coupling between atmospheric dynamics, marine boundary layer properties, convection, and the dust-laden Saharan Air Layer in the data-sparse tropical East Atlantic region. CPEX-CV provided measurements of African Easterly Wave environments, diurnal cycle impacts on convective lifecycle, and several Saharan dust outbreaks, including the highest dust optical depth observed by the DC-8 interacting with what would become Tropical Storm Hermine. Preliminary results from CPEX-CV underscore the positive impact of dedicated tropical East Atlantic observations on downstream forecast skill, including sampling environmental forcings impacting the development of several non-developing and developing convective systems such as Hurricanes Fiona and Ian. Combined airborne radar, lidar, and radiometer measurements uniquely provide near-storm environments associated with convection on various spatiotemporal scales and, with in situ observations, insights into controls on Saharan dust properties with transport. The DC-8 also collaborated with the European Space Agency to perform coordinated validation flights under the Aeolus spaceborne wind lidar and over the Mindelo ground site, highlighting the enhanced sampling potential through partnership opportunities. CPEX-CV engaged in professional development through dedicated team building exercises that equipped the team with a cohesive approach for targeting CPEX-CV science objectives and promoted active participation of scientists across all career stages.
Keywords: convective processesž, Saharan dust, aerosol, airborne measurements
Published in RUNG: 09.09.2024; Views: 686; Downloads: 6
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6. Yearlong variability of oxidative potential of particulate matter in an urban Mediterranean environmentD. Paraskevopoulou, Aikaterini Bougiatioti, Iasonas Stavroulas, T. Fang, Maria Lianou, Eleni Liakakou, Evangelos Gerasopoulos, R. Weber, Athanasios Nenes, Nikolaos Mihalopoulos, 2019, original scientific article Abstract: The oxidative potential (OP) of fine and coarse fractions of ambient aerosols was studied in the urban environment of Athens, Greece. OP was quantified using a dithiothreitol (DTT) assay, applied to the water soluble fraction of aerosol that was extracted from 361 fine and 84 coarse mode of 24-h and 12-h filter samples over a one-year period. During the cold period, samples were collected on a 12-h basis, to assess the impact of night-time biomass burning emissions from domestic heating on OP. The chemical characteristics of aerosols were measured in parallel using an Aerosol Chemical Speciation Monitoring (ACSM) and a 7-wavelength Aethalometer. A source apportionment analysis on the ACSM data resulted in the identification of organic aerosol (OA) factors on a seasonal basis. A good correlation of OP with NO3−, NH4+, BC (Black Carbon), Organics and LV-OOA (low volatility oxygenated OA) was found during winter, revealing the importance of combustion and aging processes for OP. During the summertime, a good correlation between OP and SO4−2 and NH4+indicates its association with regional aerosol – thus the importance of oxidative aging that reduces its association with any characteristic source. Multiple regression analysis during winter revealed that highly oxygenated secondary aerosol (LV-OOA) and, to a lesser extent, fresh biomass burning (BBOA) and fossil fuel (HOA) organic aerosol, are the prime contributors to the OP of fine aerosol, with extrinsic toxicities of 54 ± 22 pmol min−1 μg−1, 28 ± 7 and 17 ± 4 pmol min−1μg−1, respectively. In summer, OP cannot be attributed to any of the identified components and corresponds to a background aerosol value. In winter however, the regression model can reproduce satisfactorily the water soluble DTT activity of fine aerosol, providing a unique equation for the estimation of aerosol OP in an urban Mediterranean environment.
Keywords: oxidative potential, reactive oxygen species, DTT assay, particulate matter, urban aerosol
Published in RUNG: 13.05.2024; Views: 1211; Downloads: 0
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7. Summertime particulate matter and its composition in GreeceM. A. Tsiflikiotou, E. Kostenidou, D. K. Papanastasiou, D. Patoulias, Pavlos Zarmpas, D. Paraskevopoulou, E. Diapouli, Christos Kaltsonoudis, Kalliopi Florou, Iasonas Stavroulas, 2019, original scientific article Abstract: During the summer of 2012 a coordinated field campaign was conducted in multiple locations in Greece in order to characterize the ambient particulate matter (PM) levels, its chemical composition and the contribution of the regional and local sources. PM1, PM2.5 and PM10 samples were collected simultaneously at seven different sites in Greece: an urban and a suburban station in Patras, a suburban station in Thessaloniki, a suburban and an urban background station in Athens, a rural background station at the Navarino Environmental Observatory (NEO) in southwestern Peloponnese and a remote background site at Finokalia in the northeastern part of Crete. The sites were selected to facilitate the estimation of the contribution of the local emission sources and long range transport.
Sulfate and organics were the major PM1 components in all sites suggesting that high sulfate levels still remain in parts of Europe. The photochemistry of the Eastern Mediterranean can convert rapidly the emitted sulphur dioxide to sulfate. Our analysis indicated significant sulfate production over the area, with high sulfate levels, especially in the remote site of Finokalia, associated with air masses that had passed over Turkey. There was high regional secondary organic aerosol production dominating organic aerosol levels even in a major city like Athens. High organic aerosol levels were associated with air masses that had crossed the Balkans with a significant biogenic component. The average PM2.5 concentration ranged from 13 to 18 μg m−3 in the different sites. There were unexpected significant gradients in the concentrations of secondary aerosol components in length scales of a few hundred kilometers. The low concentrations of measured PM2.5 nitrate are mostly organic nitrates and supermicrometer nitrate associated with sea-salt and dust. Dust was a significant PM10 constituent in all areas and was quite variable in space showing the importance of the local sources.
Keywords: PM2.5, sulfate aerosol, secondary inorganic aerosol, secondary organic aerosol, Greece
Published in RUNG: 13.05.2024; Views: 1099; Downloads: 0
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8. Sources and processes that control the submicron organic aerosol composition in an urban Mediterranean environment (Athens) : a high temporal-resolution chemical composition measurement studyIasonas Stavroulas, Aikaterini Bougiatioti, Georgios Grivas, D. Paraskevopoulou, M. Tsagkaraki, Pavlos Zarmpas, Eleni Liakakou, Evangelos Gerasopoulos, Nikolaos Mihalopoulos, 2019, original scientific article Abstract: Submicron aerosol chemical composition was studied during a year-long
period (26 July 2016–31 July 2017) and two wintertime intensive campaigns
(18 December 2013–21 February 2014 and 23 December 2015–17 February 2016),
at a central site in Athens, Greece, using an Aerosol Chemical Speciation
Monitor (ACSM). Concurrent measurements included a particle-into-liquid
sampler (PILS-IC), a scanning mobility particle sizer (SMPS), an AE-33
Aethalometer, and ion chromatography analysis on 24 or 12 h filter samples.
The aim of the study was to characterize the seasonal variability of the main
submicron aerosol constituents and decipher the sources of organic aerosol
(OA). Organics were found to contribute almost half of the submicron mass,
with 30 min resolution concentrations during wintertime reaching up to
200 µg m−3. During winter (all three campaigns combined),
primary sources contributed about 33 % of the organic fraction, and comprised
biomass burning (10 %), fossil fuel combustion (13 %), and cooking
(10 %), while the remaining 67 % was attributed to secondary aerosol.
The semi-volatile component of the oxidized organic aerosol (SV-OOA;
22 %) was found to be clearly linked to combustion sources, in
particular biomass burning; part of the very oxidized,
low-volatility component (LV-OOA; 44 %) could also be attributed to the
oxidation of emissions from these primary combustion sources. These results, based on the combined contribution of biomass burning organic
aerosol (BBOA) and SV-OOA, indicate the importance of increased biomass
burning in the urban environment of Athens as a result of the economic recession.
During summer, when concentrations of fine aerosols are considerably lower,
more than 80 % of the organic fraction is attributed to secondary aerosol
(SV-OOA 31 % and LV-OOA 53 %). In contrast to winter, SV-OOA appears
to result from a well-mixed type of aerosol that is linked to fast photochemical
processes and the oxidation of primary traffic and biogenic emissions.
Finally, LV-OOA presents a more regional character in summer, owing to the
oxidation of OA over the period of a few days.
Keywords: ACSM, organic aerosol, PMF, source apportionment
Published in RUNG: 13.05.2024; Views: 1179; Downloads: 5
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9. Applicability of benchtop multi-wavelength polar photometers to off-line measurements of the Multi-Angle Absorption Photometer (MAAP) samplesSara Valentini, Vera Bernardoni, Ezio Bolzacchini, Davide Ciniglia, Luca Ferrero, Alice Corina Forello, Dario Massabò, Marco Pandolfi, Paolo Prati, Jesús Yus-Díez, 2021, original scientific article Keywords: aerosol absorption coefficient, equivalent black carbon, MAAP, polar photometer, multi-wavelength
Published in RUNG: 13.05.2024; Views: 1028; Downloads: 2
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10. Particle number size distribution statistics at City-Centre Urban Background, urban background, and remote stations in Greece during summerS. Vratolis, Maria I. Gini, Spiros Bezantakos, Iasonas Stavroulas, Nikos Kalivitis, E. Kostenidou, E. Louvaris, D. Siakavaras, George Biskos, Nikolaos Mihalopoulos, 2019, original scientific article Abstract: Particle number size distribution measurements were conducted during the summer of 2012 at City-Centre Urban Background (Patras-C), Urban Background (ICE-HT in Patras, DEM in Athens, EPT in Thessaloniki), and Regional Background stations (FIN in Crete). At the City-Centre Urban Background station, the average number distribution had a geometric mean diameter peak approximately at 60 nm and the highest number concentration, whereas at the Regional Background station and the Urban Background stations it displayed a major peak approximately at 100 nm, with the Regional Background station exhibiting the lowest number concentration. The particle number size distribution at each site was divided into size fractions and, based on their diurnal variation and previous studies, we concluded that the main sources for the City-Centre Urban Background station are traffic and the regional background concentration, for the Urban Background stations fresh traffic, aged traffic, cooking and the regional background concentration, and for the Regional Background station local activities (tourism, cooking) and regional background concentration. The median number concentration that is attributed to regional background concentration for the City-Centre Urban Background, the Urban Background and the Regional Background stations are respectively 13, 29 and 45% of the total number concentration. Nucleation events were identified at DEM station, where the newly formed particles accounted for 4% of the total particle concentration for the measurement period in the size range 10–20 nm, EPT, where they accounted for 12%, and FIN, where they accounted for 1%, respectively. New Particle Formation events contribution during summer to Condensation Cloud Nuclei were therefore insignificant in the Eastern Mediterranean. Modal analysis was performed on the number distributions and the results were classified in clusters. At the City-Centre Urban Background station, the cluster-source that dominated number concentration and frequency is related to fresh and aged traffic emissions, at the Urban Background stations aged traffic emissions, while at the Regional Background station number and frequency were dominated by the regional background concentration. Based on cluster analysis, 18% of the median number distribution was due to long range transport at the City-Centre Urban Background site, 37% at the Urban Background sites, and 59% at the Regional Background site. The Flexible Particle Dispersion Model (FLEXPART) was used in order to acquire geographic origin clusters and we concluded that the Etesian flow increases the median regional background number concentration in the Mediterranean basin by a factor of 2.5–4.
Keywords: Mediterranean aerosol, particle number size distribution clustering, FLEXPART clustering
Published in RUNG: 13.05.2024; Views: 1199; Downloads: 0
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