1. On-flight intercomparison of three miniature aerosol absorption sensors using unmanned aerial systems (UASs)Michael Pikridas, Spiros Bezantakos, Griša Močnik, Christos Keleshis, Fred Brechtel, Iasonas Stavroulas, Gregoris Demetriades, Panayiota Antoniou, Panagiotis Vouterakos, Marios Argyrides, 2019, izvirni znanstveni članek Opis: The present study investigates and compares the ground and in-flight
performance of three miniaturized aerosol absorption sensors integrated
on board small-sized Unmanned Aerial Systems (UASs). These sensors were
evaluated during two contrasted field campaigns performed at an urban site,
impacted mainly by local traffic and domestic wood burning sources (Athens,
Greece), and at a remote regional background site, impacted by long-range
transported sources including dust (Cyprus Atmospheric Observatory, Agia
Marina Xyliatou, Cyprus). The miniaturized sensors were first intercompared at the ground-level
against two commercially available instruments used as a reference. The
measured signal of the miniaturized sensors was converted into the
absorption coefficient and equivalent black carbon concentration (eBC). When
applicable, signal saturation corrections were applied, following the
suggestions of the manufacturers. The aerosol absorption sensors exhibited
similar behavior against the reference instruments during the two campaigns,
despite the diversity of the aerosol origin, chemical composition, sources,
and concentration levels. The deviation from the reference during both
campaigns concerning (eBC) mass was less than 8 %, while for the absorption
coefficient it was at least 15 %. This indicates that those sensors that
report black carbon mass are tuned and corrected to measure eBC more accurately than the absorption coefficient. The overall potential use of miniature aerosol absorption sensors on board
small UASs is also illustrated. UAS-based absorption measurements were used
to investigate the vertical distribution of eBC over Athens up to 1 km above
sea level during January 2016, exceeding the top of the planetary boundary
layer (PBL). Our results reveal a heterogeneous boundary layer concentration
of absorbing aerosol within the PBL intensified in the early morning hours
due to the concurrent peak traffic emissions at ground-level and the fast
development of the boundary layer. After the full development of the PBL,
homogenous concentrations are observed from 100 m a.g.l. to the PBL top.
Ključne besede: Unmanned Aerial Systems, Cyprus Atmospheric Observatory, eBC, vertical profiling, microaethalometer
Objavljeno v RUNG: 13.05.2024; Ogledov: 0; Prenosov: 0
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2. 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, izvirni znanstveni članek Opis: 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.
Ključne besede: Mediterranean aerosol, particle number size distribution clustering, FLEXPART clustering
Objavljeno v RUNG: 13.05.2024; Ogledov: 11; Prenosov: 0
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3. 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, izvirni znanstveni članek Ključne besede: megacity, submicron aerosols, urban haze, Greater Cairo, hygroscopic aerosols, ammonium chloride
Objavljeno v RUNG: 10.05.2024; Ogledov: 62; Prenosov: 0
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4. A method for quantification of mineral dust in air based on optical absorption of particles concentrated by a virtual impactor and a device performing the said method : SI3783336 (T1), 2024-02-29Luka Drinovec, Griša Močnik, Iasonas Stavroulas, Spiros Bezantakos, Michael Pikridas, Florin Unga, Jean Sciare, 2024, patent Opis: The present invention belongs to the field of devices and methods for measurement of particle concentration, more precisely to the field of devices and methods for quantification of particles based on their physical characteristics, especially with the use of optical means. The invention relates to a method for determination of ambient mineral dust concentration based on optical absorption of particles concentrated by a virtual impactor as well as a device performing the said method. The method comprises the following steps:- Sampling air samples with particle size smaller than 1 µm (PM1) and sampling air samples with particle size up to 10 µm;- Concentrating the samples with particle sizes up to 10 µm with a virtual impactor;- Measuring optical absorption of collected samples at least one wavelength from UV to IR spectre, preferably from 370 to 950 nm, most preferably at 370 nm;- Subtracting the absorption of the samples with particle size smaller than 1 µm from the absorption of the sample concentrated by the virtual impactor.
Ključne besede: dust, black carbon, aerosols
Objavljeno v RUNG: 24.04.2024; Ogledov: 674; Prenosov: 2
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5. A new optical-based technique for real-time measurements of mineral dust concentration in PM10 using a virtual impactorLuka Drinovec, Jean Sciare, Iasonas Stavroulas, Spiros Bezantakos, Michael Pikridas, FLORIN UNGA, Chrysanthos Savvides, Bojana Višnjić, Maja Remškar, Griša Močnik, 2020, izvirni znanstveni članek Opis: Atmospheric mineral dust influences Earth’s radiative
budget, cloud formation, and lifetime; has adverse
health effects; and affects air quality through the increase of
regulatory PM10 concentrations, making its real-time quantification
in the atmosphere of strategic importance. Only
few near-real-time techniques can discriminate dust aerosol
in PM10 samples and they are based on the dust chemical
composition. The online determination of mineral dust using
aerosol absorption photometers offers an interesting and
competitive alternative but remains a difficult task to achieve.
This is particularly challenging when dust is mixed with
black carbon, which features a much higher mass absorption
cross section. We build on previous work using filter photometers
and present here for the first time a highly timeresolved
online technique for quantification of mineral dust
concentration by coupling a high-flow virtual impactor (VI)
sampler that concentrates coarse particles with an aerosol absorption
photometer (Aethalometer, model AE33). The absorption
of concentrated dust particles is obtained by subtracting
the absorption of the submicron (PM1) aerosol fraction
from the absorption of the virtual impactor sample (VIPM1
method). This real-time method for detecting desert
dust was tested in the field for a period of 2 months (April and
May 2016) at a regional background site of Cyprus, in the
Eastern Mediterranean. Several intense desert mineral dust
events were observed during the field campaign with dust
concentration in PM10 up to 45 μgm
Ključne besede: aerosol absorption, mineral dust, on-line detection, air quality
Objavljeno v RUNG: 20.07.2020; Ogledov: 2797; Prenosov: 0
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