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Carbonaceous aerosols in contrasting atmospheric environments in Greek cities : evaluation of the EC-tracer methods for secondary organic carbon estimation
Dimitris G. Kaskaoutis, Georgios Grivas, Christina Theodosi, M. Tsagkaraki, D. Paraskevopoulou, Iasonas Stavroulas, Eleni Liakakou, Antonis Gkikas, Nikolaos Hatzianastassiou, Cheng Wu, 2020, izvirni znanstveni članek

Opis: This study examines the carbonaceous-aerosol characteristics at three contrasting urban environments in Greece (Ioannina, Athens, and Heraklion), on the basis of 12 h sampling during winter (January to February 2013), aiming to explore the inter-site differences in atmospheric composition and carbonaceous-aerosol characteristics and sources. The winter-average organic carbon (OC) and elemental carbon (EC) concentrations in Ioannina were found to be 28.50 and 4.33 µg m−3, respectively, much higher than those in Heraklion (3.86 µg m−3 for OC and 2.29 µg m−3 for EC) and Athens (7.63 µg m−3 for OC and 2.44 µg m−3 for EC). The winter OC/EC ratio in Ioannina (6.53) was found to be almost three times that in Heraklion (2.03), indicating a larger impact of wood combustion, especially during the night, whereas in Heraklion, emissions from biomass burning were found to be less intense. Estimations of primary and secondary organic carbon (POC and SOC) using the EC-tracer method, and specifically its minimum R-squared (MRS) variant, revealed large differences between the sites, with a prevalence of POC (67–80%) in Ioannina and Athens and with a larger SOC fraction (53%) in Heraklion. SOC estimates were also obtained using the 5% and 25% percentiles of the OC/EC data to determine the (OC/EC)pri, leading to results contrasting to the MRS approach in Ioannina (70–74% for SOC). Although the MRS method provides generally more robust results, it may significantly underestimate SOC levels in environments highly burdened by biomass burning, as the fast-oxidized semi-volatile OC associated with combustion sources is classified in POC. Further analysis in Athens revealed that the difference in SOC estimates between the 5% percentile and MRS methods coincided with the semi-volatile oxygenated organic aerosol as quantified by aerosol mass spectrometry. Finally, the OC/Kbb+ ratio was used as tracer for decomposition of the POC into fossil-fuel and biomass-burning components, indicating the prevalence of biomass-burning POC, especially in Ioannina (77%).
Ključne besede: carbonaceous aerosols, inorganic species, POC-SOC estimation, biomass burning, MRS method, Greece
Objavljeno v RUNG: 10.05.2024; Ogledov: 129; Prenosov: 3
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Impacts of severe residential wood burning on atmospheric processing, water-soluble organic aerosol and light absorption, in an inland city of Southeastern Europe
Dimitris G. Kaskaoutis, Georgios Grivas, K. Oikonomou, P. Tavernaraki, Kyriaki Papoutsidaki, M. Tsagkaraki, Iasonas Stavroulas, Pavlos Zarmpas, D. Paraskevopoulou, Aikaterini Bougiatioti, 2022, izvirni znanstveni članek

Opis: This study examines the concentrations and characteristics of carbonaceous aerosols (including saccharides) and inorganic species measured by PM2.5 filter sampling and a multi-wavelength Aethalometer during two campaigns in a mountainous, medium-sized, Greek city (Ioannina). The first campaign was conducted in summer and used as a baseline of low concentrations, while the second took place in winter under intensive residential wood burning (RWB) emissions. Very high winter-mean OC concentrations (26.0 μg m−3) were observed, associated with an OC/EC ratio of 9.9, and mean BCwb and PM2.5 levels of 4.5 μg m−3 and 57.5 μg m−3, respectively. Simultaneously, record-high levoglucosan (Lev) concentrations (mean: 6.0 μg m−3; max: 15.9 μg m−3) were measured, revealing a severely biomass burning (BB)-laden environment. The water-soluble OC component (WSOC) accounted for 56 ± 9% of OC in winter, exhibiting high correlations (R2 = 0.93–0.97) with BB tracers (nss-K+, BCwb, Lev), nitrate and light absorption, potentially indicating the formation of water-soluble brown carbon (BrC) from fast oxidation processes. The examination of diagnostic ratios involving BB tracers indicated the prevalence of hardwood burning, while the mean Lev/OC ratio (22%) was remarkably higher than literature values. Applying a mono-tracer method based on levoglucosan, we estimated very high BB contributions to OC (∼92%), EC (∼64%) and WSOC (∼87%) during winter. On the contrary, low levels were registered during summer for all carbonaceous components, with winter/summer ratios of 4–5 for PM2.5 and BC, 10 for OC, 30 for BCwb and ∼1100 for levoglucosan. The absence of local BB sources in summer, combined with the photochemical processing and aging of regional organic aerosols, resulted in higher WSOC/OC fractions (64 ± 13%). The results indicate highly soluble fine carbonaceous aerosol fraction year-round, which when considered alongside the extreme concentration levels in winter can have important implications for short- and long-term health effects.
Ključne besede: carbonaceous aerosols, biomass burning, levoglucosan, WSOC, heterogeneous chemistry, Greece
Objavljeno v RUNG: 10.05.2024; Ogledov: 138; Prenosov: 2
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Identification and detailed characterization of ▫$PM_10$▫ sources in an Alpine valley influenced by a cement plant
Kristina Glojek, Katja Džepina, Griša Močnik, 2023, objavljeni povzetek znanstvenega prispevka na konferenci

Opis: The contribution of traffic and wood burning to particulate matter (PM) across the Alps is widely recognized and studied (Herich et al., 2014 and references therein; Glojek et al., 2020). However, studies on valleys with cement production are scarce (Kim et al., 2003; Rovira et al., 2018) despite its large PM emissions and potential toxic properties (Erik et al., 2022; Weinbruch et al., 2023). We aim to identify and characterize sources’ contribution to the complex mixture of carbonaceous and mineral PM10 in a representative Alpine valley. Quartz filter samples of PM10 were collected daily from December 2020 to December 2021 and analyzed using different chemical techniques. In the same period equivalent black carbon (eBC) measurements were taken with the Aethalometer AE43. The measured species were analyzed using Positive Matrix Factorization (PMF) model (EPA PMF 5.0) with newly added tracers, i. e. source-specific eBC (Sandradewi et al., 2008) and organic species (2-MT, 3-MBTCA, phtalic acid, MSA and oxalate). The final PMF results were compared to online PMF-factors (SoFi Pro) derived from PM10 and PM2.5 elemental measurements (Cooper Xact 625i). Ten factors were identified at the site, including commonly detected biomass burning, traffic, nitrate- and sulfate-rich, aged sea salt and mineral dust. With the added additional organic traces, primary biogenic and secondary oxidation were recognized as well. In addition, two unusual factors were disclosed, contributing 10% to annual PM10. Namely, Cl-rich and a mineral dust-rich factor, which we name the cement kiln factor. We associate these two factors to different processes in the cement plant. The outputs of the study provide vital information about the influence of cement production on PM10 concentrations in complex environments and are useful for PM control strategies and actions.
Ključne besede: PM pollution, carbonaceous aerosols, source apportionment, industry
Objavljeno v RUNG: 10.01.2024; Ogledov: 730; Prenosov: 0
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