71. Regional new particle formation over the Eastern Mediterranean and Middle EastPanayiotis Kalkavouras, Aikaterini Bougiatioti, Tareq Hussein, Nikos Kalivitis, Iasonas Stavroulas, Panagiotis Michalopoulos, Nikolaos Mihalopoulos, 2021, original scientific article Abstract: Atmospheric new particle formation (NPF) events taking place over large distances between locations, featuring similar characteristics, have been the focus of studies during the last decade. The exact mechanism which triggers NPF still remains indefinable, so are the circumstances under which simultaneous occurrence of such events take place in different environments, let alone in environments which are parted by over 1200 km. In this study, concurrent number size distribution measurements were conducted in the urban environments of Athens (Greece) and Amman (Jordan) as well as the regional background site of Finokalia, Crete, all located within a distance of almost 1300 km for a 6-month period (February–July 2017). During the study period Athens and Finokalia had similar occurrence of NPF (around 20%), while the occurrence in Amman was double. When focusing on the dynamic characteristics at each site, it occurs that formation and growth rates at Amman are similar to those at Finokalia, while lower values in Athens can be ascribed to a higher pre-existing particle number at this urban site. By comparing common NPF events there are 5 concomitant days between all three sites, highly related to air masses origin. Additionally, for another 19 days NPF takes place simultaneously between Finokalia and Amman, which also share common meteorological characteristics, adding to a total of 60% out of 41 NPF events observed at Finokalia, also simultaneously occurring in Amman.
Keywords: NPF, Eastern Mediterranean, particle number size distributions, concurrent regional events
Published in RUNG: 10.05.2024; Views: 196; Downloads: 3
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72. Cooking as an organic aerosol source leading to urban air quality degradationIasonas Stavroulas, Aikaterini Bougiatioti, Georgios Grivas, Eleni Liakakou, Kalliopi Petrinoli, Konstantinos Kourtidis, Evangelos Gerasopoulos, Nikolaos Mihalopoulos, 2024, original scientific article Keywords: ACSM, PMF, cooking organic aerosol, meat charbroiling
Published in RUNG: 10.05.2024; Views: 194; Downloads: 0
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73. Foods2012 Keywords: food sciences and technology, food chemistry and physical properties, food engineering and production, food security and safety, food toxicology, sensory and food quality, food analysis, functional foods, food and health, food psychology, food and environment
Published in RUNG: 10.05.2024; Views: 221; Downloads: 1
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74. Vertical profiling of fresh biomass burning aerosol optical properties over the Greek urban city of Ioannina, during the PANACEA winter campaignChristina-Anna Papanikolaou, Alexandros Papayannis, M. Mylonaki, Romanos Foskinis, Panagiotis Kokkalis, Eleni Liakakou, Iasonas Stavroulas, O. Soupiona, Nikolaos Hatzianastassiou, Maria Gavrouzou, 2022, original scientific article Abstract: Vertical profiling of aerosol particles was performed during the PANhellenic infrastructure for Atmospheric Composition and climatE chAnge (PANACEA) winter campaign (10 January 2020–7 February 2020) over the city of Ioannina, Greece (39.65° N, 20.85° E, 500 m a.s.l.). The middle-sized city of Ioannina suffers from wintertime air pollution episodes due to biomass burning (BB) domestic heating activities. The lidar technique was applied during the PANACEA winter campaign on Ioannina city, to fill the gap of knowledge of the spatio-temporal evolution of the vertical mixing of the particles occurring during these winter-time air pollution episodes. During this campaign the mobile single-wavelength (532 nm) depolarization Aerosol lIdAr System (AIAS) was used to measure the spatio-temporal evolution of the aerosols’ vertical profiles within the Planetary Boundary Layer (PBL) and the lower free troposphere (LFT; up to 4 km height a.s.l.). AIAS performed almost continuous lidar measurements from morning to late evening hours (typically from 07:00 to 19:00 UTC), under cloud-free conditions, to provide the vertical profiles of the aerosol backscatter coefficient (baer) and the particle linear depolarization ratio (PLDR), both at 532 nm. In this study we emphasized on the vertical profiling of very fresh (~hours) biomass burning (BB) particles originating from local domestic heating activities in the area. In total, 33 out of 34 aerosol layers in the lower free troposphere were characterized as fresh biomass burning ones of local origin, showing a mean particle linear depolarization value of 0.04 ± 0.02 with a range of 0.01 to 0.09 (532 nm) in a height region 1.21–2.23 km a.s.l. To corroborate our findings, we used in situ data, particulate matter (PM) concentrations (PM2.5) from a particulate sensor located close to our station, and the total black carbon (BC) concentrations along with the respective contribution of the fossil fuel (BCff) and biomass/wood burning (BCwb) from the Aethalometer. The PM2.5 mass concentrations ranged from 5.6 to 175.7 μg/m3, while the wood burning emissions from residential heating were increasing during the evening hours, with decreasing temperatures. The BCwb concentrations ranged from 0.5 to 17.5 μg/m3, with an extremely high mean contribution of BCwb equal to 85.4%, which in some cases during night-time reached up to 100% during the studied period.
Keywords: lidar, depolarization ratio, fresh biomass burning aerosols, domestic heating, black carbon, PM2.5
Published in RUNG: 10.05.2024; Views: 187; Downloads: 3
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75. Source apportionment of fine and ultrafine particle number concentrations in a major city of the Eastern MediterraneanPanayiotis Kalkavouras, Georgios Grivas, Iasonas Stavroulas, Kalliopi Petrinoli, Aikaterini Bougiatioti, Eleni Liakakou, Evangelos Gerasopoulos, Nikolaos Mihalopoulos, 2024, original scientific article Keywords: UFP, PNSD, receptor modelling, lockdown, Athens
Published in RUNG: 10.05.2024; Views: 199; Downloads: 0
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76. The effect of the averaging period for PMF analysis of aerosol mass spectrometer measurements during offline applicationsChristina Vasilakopoulou, Iasonas Stavroulas, Nikolaos Mihalopoulos, Spyros N. Pandis, 2022, original scientific article Abstract: Offline aerosol mass spectrometer (AMS) measurements can
provide valuable information about ambient organic aerosols in areas and
periods in which online AMS measurements are not available. However, these
offline measurements have a low temporal resolution, as they are based on
filter samples usually collected over 24 h. In this study, we examine
whether and how this low time resolution affects source apportionment
results. We used a five-month period (November 2016–March 2017) of online
measurements in Athens, Greece, and performed positive matrix factorization (PMF)
analysis to both the original dataset, which consists of 30 min
measurements, and to time averages from 1 up to 24 h. The 30 min results
indicated that five factors were able to represent the ambient organic
aerosol (OA): a biomass burning organic aerosol factor (BBOA), which contributed
16 % of the total OA; hydrocarbon-like OA (HOA) (29 %); cooking OA (COA) (20 %); more-oxygenated OA (MO-OOA) (18 %); and less-oxygenated OA (LO-OOA) (17 %). Use of the daily averages resulted in estimated average contributions that were within 8 % of the total OA compared with the high-resolution analysis for the five-month period. The most important difference was for the BBOA contribution, which was overestimated (25 % for low resolution versus 17 % for high resolution) when daily averages were used. The estimated secondary OA varied from 35 % to 28 % when the averaging
interval varied between 30 min and 24 h. The high-resolution results are
expected to be more accurate, both because they are based on much larger
datasets and because they are based on additional information about the
temporal source variability. The error for the low-resolution analysis was
much higher for individual days, and its results for high-concentration days in particular are quite uncertain. The low-resolution analysis
introduces errors in the determined AMS profiles for the BBOA and LO-OOA
factors but determines the rest relatively accurately (theta angle around
10∘ or less).
Keywords: AMS, offline PMF, ACSM, organic aerosols
Published in RUNG: 10.05.2024; Views: 217; Downloads: 3
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77. Rolling vs. seasonal PMF : real-world multi-site and synthetic dataset comparisonMarta Via, Gang Chen, Francesco Canonaco, Kaspar Rudolf Daellenbach, Benjamin Chazeau, Hasna Chebaicheb, Jianhui Jiang, Hannes Keernik, Chunshui Lin, Nicolas Marchand, 2022, original scientific article Abstract: Abstract. Particulate matter (PM) has become a major concern in terms of human health
and climate impact. In particular, the source apportionment (SA) of organic
aerosols (OA) present in submicron particles (PM1) has gained relevance
as an atmospheric research field due to the diversity and complexity of its
primary sources and secondary formation processes. Moreover, relatively
simple but robust instruments such as the Aerosol Chemical Speciation
Monitor (ACSM) are now widely available for the near-real-time online
determination of the composition of the non-refractory PM1. One of the
most used tools for SA purposes is the source-receptor positive matrix
factorisation (PMF) model. Even though the recently developed rolling PMF technique has
already been used for OA SA on ACSM datasets, no study has assessed its
added value compared to the more common seasonal PMF method using a practical
approach yet. In this paper, both techniques were applied to a synthetic
dataset and to nine European ACSM datasets in order to spot the main output
discrepancies between methods. The main advantage of the synthetic dataset
approach was that the methods' outputs could be compared to the expected
“true” values, i.e. the original synthetic dataset values. This approach
revealed similar apportionment results amongst methods, although the
rolling PMF profile's adaptability feature proved to be advantageous, as it
generated output profiles that moved nearer to the truth points. Nevertheless,
these results highlighted the impact of the profile anchor on the solution,
as the use of a different anchor with respect to the truth led to
significantly different results in both methods. In the multi-site study,
while differences were generally not significant when considering year-long
periods, their importance grew towards shorter time spans, as in intra-month
or intra-day cycles. As far as correlation with external measurements is
concerned, rolling PMF performed better than seasonal PMF globally for the ambient
datasets investigated here, especially in periods between seasons. The results of this
multi-site comparison coincide with the synthetic dataset in terms of
rolling–seasonal similarity and rolling PMF reporting moderate improvements. Altogether, the
results of this study provide solid evidence of the robustness of both
methods and of the overall efficiency of the recently proposed rolling PMF
approach.
Keywords: particulate matter, synthetic dataset comparison, source apportionment, organic aerosols
Published in RUNG: 10.05.2024; Views: 196; Downloads: 4
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78. Submicron aerosol pollution in Greater Cairo (Egypt) : a new type of urban haze?Aliki Christodoulou, Spiros Bezantakos, Efstratios Bourtsoukidis, Iasonas Stavroulas, Michael Pikridas, Konstantina Oikonomou, Minas Iakovides, Salwa K. Hassan, Mohamed Boraiy, Mostafa El-Nazer, 2024, original scientific article Keywords: megacity, submicron aerosols, urban haze, Greater Cairo, hygroscopic aerosols, ammonium chloride
Published in RUNG: 10.05.2024; Views: 204; Downloads: 2
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79. Borderless aeasthetics : the new uglySandra Jovanovska, 2024, master's thesis Abstract: Through the lens of ugliness, the purpose of this Master’s thesis is to explore a potential model of a new unrestricted aesthetics. I, hereby, refer to an aesthetics beyond its canonical order, an individualistically-driven scheme of standards or perhaps no standards at all. All can be simplified with Eco’s quote on the opposition of the beautiful and the ugly: ’A beautiful nose shouldn’t be longer than that or shorter than that, on the contrary, an ugly nose can be as long as the one of Pinocchio, or as big as the trunk of an elephant, or like the beak of an eagle, and so ugliness is unpredictable, and offers an infinite range of possibility’. While the aesthetics of beauty has already positioned framework of rules in regards to proportion, symmetry, and harmony, the aesthetics of ugliness has no particular guidelines and limitations whatsoever. Unlike the beautiful, what we perceive as ugly doesn’t have its lawfulness, because for a long time in the history of art, ugliness was just the opposite face of beauty. As a consequence, the ugly embodies a big category of undetermined standards in visual arts and culture, which leads to it becoming a large unmapped territory of boundless autonomy. The ugly is in that context the key to facing and unleashing our phenomenological fears of bleak dark deformed realities that lie unchallenged and unaddressed on account of ugliness’ taboo status. Thus, when familiarised, I believe ugliness in art has a powerful impact, a quality that we have to yet begin to understand to get a full image of ourselves, for if we rely on beauty, as we did for such a long time in history, we are depriving ourselves of a true holistic proportion in art.
Keywords: art, man, ugliness, new, aesthetics, beauty, artist, time, image, Dada, history, context, different, body, personal, culture, transform, political, philosophy, standard, perspective.
Published in RUNG: 10.05.2024; Views: 179; Downloads: 4
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80. Increase in secondary organic aerosol in an urban environment : Increase in secondary organic aerosol in an urban environmentMarta Via, Maria Cruz Minguillon, Cristina Reche, Xavier Querol, Andrés Alastuey, 2021, original scientific article Abstract: The evolution of fine aerosol (PM1) species as well as the contribution of potential sources to the total organic aerosol (OA) at an urban background site in Barcelona, in the western Mediterranean basin (WMB) was investigated. For this purpose, a quadrupole aerosol chemical speciation monitor (Q-ACSM) was deployed to acquire real-time measurements for two 1-year periods: May 2014–May 2015 (period A) and September 2017–October 2018 (period B). Total PM1 concentrations showed a slight decrease (from 10.1 to 9.6 μgm�3 from A to B), although the relative contribution of inorganic and organic compounds varied significantly. Regarding inorganic compounds, SO42- , black carbon(BC) and NH4+ showed a significant decrease from period
A to B (21 %, 18% and 9 %, respectively), whilst NO3- concentrations were higher in B (8 %). Source apportionment
revealed OA contained 46% and 70% secondary OA (SOA) in periods A and B, respectively. Two secondary oxygenated OA sources (OOA) were differentiated by their oxidation status (i.e. ageing): less oxidized (LO-OOA) and more oxidized (MO-OOA). Disregarding winter periods, when LO-OOA production was not favoured, LO-OOA transformation into MO-OOA was found to be more effective in
period B. The lowest LO-OOA-to-MO-OOA ratio, excluding winter, was in September–October 2018 (0.65), implying an accumulation of aged OA after the high temperature and solar radiation conditions in the summer season. In addition to temperature, SOA (sum of OOA factors) was enhanced by exposure to NOx-polluted ambient and other pollutants, especially to O3 and during afternoon hours. The anthropogenic primary OA sources identified, cooking-related
OA (COA), hydrocarbon-like OA (HOA), and biomass burning OA (BBOA), decreased from period A to B in both absolute concentrations and relative contribution (as a whole, 44% and 30 %, respectively). However, their concentrations and proportion to OA grew rapidly during highly polluted episodes. The influence of certain atmospheric episodes on OA sources was also assessed. Both SOA factors were boosted with long- and medium-range circulations, especially those coming from inland Europe and the Mediterranean (triggering mainly MO-OOA) and summer breeze-driven regional circulation (mainly LO-OOA). In contrast, POA was
enhanced either during air-renewal episodes or stagnation anticyclonic events.
Keywords: aerosol, organic aerosol, source apportionment, PM1, particulate matter
Published in RUNG: 10.05.2024; Views: 213; Downloads: 3
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