1. Comparison of on- and off-line source apportionment with wood-burning, traffic and industrial sourcesKristina Glojek, Thuy Vy Dinh Ngoc, M. Manousakas, Sylvain Weber, Gaëlle Uzu, Rhabira Elazzouzi, Katja Džepina, Markus Furger, Sophie Darfeuil, Griša Močnik, 2024, published scientific conference contribution abstract Abstract: Recent studies show that combining data with different time resolutions results in more detailed and likely more accurate source apportionment (SA) (Hopke et al., 2020; Manousakas et al., 2022; Via et al., 2023). Despite the advantages, SA studies, combining 24-hour filters and highly time-resolved analyses, are limited. This research aims to compare on- and off-line SA results in a pre-Alpine valley with a variety of sources. A comprehensive SA study of the local and regional PM sources and their size-segregated elemental fraction will be presented.
PM10 was sampled daily on quartz filters from November 2020 to November 2021 and analyzed for a large array of chemical species. Equivalent black carbon (eBC) measurements were taken with the Aethalometer AE33. Hourly elemental PM10 and PM2.5 composition was measured in parallel with two Xact 625i from February until May 2021. Positive Matrix Factorization (PMF) was used to determine the sources of PM10 (off-line PMF) with 24-hour time resolution, and of the elemental fraction of PM (on-line PMF) with 1-hour time resolution for the overlapping time period. For off-line PMF, chemical species together with the source-specific eBC (Sandradewi et al., 2008) were used. For on-line PMF, two analyses were performed on the elemental composition: using PM10, and using a combination of PM2.5 and PMcoarse (PM10-PM2.5). The final off-line PM10 PMF results were compared to on-line elemental PM PMF and assessed accordingly.
A combination of the different PMF models with various instrument data resulted in improved SA in terms of the number of identified sources and their uncertainties. The off-line PMF resolved ten PM10 sources (Fig. 1, left), while the on-line elemental PM10 and the combined elemental PM2.5+coarse PMF recognized 6 and 7 factors, respectively (Fig. 1, right).
Due to large number of samples, we were able to separate between the sources with strong seasonality and sources featuring stability throughout the year. The study disclosed two rarely encountered factors, i.e., chloride-rich (chlorine-rich in case of on-line PMF) and cement dust. Introduction of source-specific eBC in the off-line PMF model resulted in more stable factor solutions.The high-resolution on-line PMF enabled us to distinguish between regional and local sources (see mineral dust factors). Furthermore, the size-segregated on-line PMF provided more speciated sources (traffic separation into heavy-duty and light-duty vehicles). A very good regression (R2 > 0.7, slopes = 0.05–0.35, p < 0.001) between the compared off-line PM10 and on-line elemental PM10 (daily averages) factors’ concentrations confirmed the adequacy of the SAs. Further work involves a direct comparison of fractions of the elements in the sources’ chemical profiles.
The study clearly shows the advantages and limitations of the different PMF models. A combined use of various SA approaches appears to be a promising way towards a comprehensive analysis of the PM sources in complex environments. Keywords: positive matrix factorization, PM10 composition, metals, Xact, HVS digitel Published in RUNG: 24.01.2025; Views: 329; Downloads: 7
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2. Vpliv prometa, kurjenja lesa in industrije na sestavo in toksičnost delcev PMKristina Glojek, Thuy Vy Dinh Ngoc, Sylvain Weber, Gaëlle Uzu, M. Manousakas, Rhabira Elazzouzi, Katja Džepina, Sophie Darfeuil, Patrick Ginot, Rahela Žabkar, Janja Turšič, Andrej Podkoritnik, Griša Močnik, 2024, published scientific conference contribution (invited lecture) Abstract: Viri, ki največ prispevajo k masi PM10, nimajo nujno najvišjega Oksidativnega Potenciala (OP), parametra, s katerim ocenimo možnost delcev PM, da oksidirajo testno spojino, s čimer ocenimo njihov nezaželeni vpliv na zdravje. V obsežni študiji analize virov PM10 in OP v Kanalu ob Soči smo izmerili koncentracije PM10, ki so primerljive z nekaterimi dolinami v Alpah in drugih hribovitih območjih Evrope, vrednosti OP pa so bile med najvišjimi izmerjenimi doslej v EU. Vira z največjim OP na enoto mase (OPm) kot tudi OP na enoto zraka (OPv) sta kurjenje biomase in vir bogat s kloridi, ki ga povezujemo z delovanjem cementarne. Izmerjene vrednosti OP v Kanalu ob Soči zahtevajo sprejetje ukrepov, ki bodo zmanjšali obremenitve antropogenih virov na ranljivo lokalno prebivalstvo. Keywords: onesnažen zrak, delci PM, oksidativni potencial, določanje virov Published in RUNG: 27.11.2024; Views: 461; Downloads: 1 This document has many files! More... |
3. Annual variation of source contributions to ▫$PM_10$▫ and oxidative potential in a mountainous area with traffic, biomass burning, cement-plant and biogenic influencesKristina Glojek, Thuy Vy Dinh Ngoc, Sylvain Weber, Gaëlle Uzu, M. Manousakas, Rhabira Elazzouzi, Katja Džepina, Sophie Darfeuil, Patrick Ginot, Andrej Podkoritnik, Griša Močnik, 2024, original scientific article Keywords: air pollution, extensive PM chemical characterization, positive matrix factorization (PMF), new source identification, health metric Published in RUNG: 03.06.2024; Views: 1370; Downloads: 16
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4. 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: 1339; Downloads: 0 This document has many files! More... |
5. Linguistic equilibrium with local and world languages : challenges of globalisationDenis Davydov, Alexander Shapoval, Shlomo Weber, 2018, original scientific article Abstract: In this paper we introduce a model of a society with two distinct linguistic groups, each consisting of heterogeneous individuals speaking their native language. There is also a world language so that every individual is faced with four learning choices: to study the other local language only, to study the world language only, to study both, and to refrain from studying either language. We examine the Nash equilibiria of that game determined by communicative benefits (Selten & Pool), and address inefficiency of the equilibrium. We then show that government subsidies for language learning could serve as welfare‐enhancing policies. Finally, we analyze the three‐language policy, certain variants of which have been adopted in multilingual countries or regions. Keywords: three-language formula, Nash equilibrium, inefficiency Published in RUNG: 07.04.2021; Views: 2752; Downloads: 99
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