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: 139; Prenosov: 1
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2. Ambient carbonaceous aerosol levels in Cyprus and the role of pollution transport from the Middle EastAliki Christodoulou, Iasonas Stavroulas, Mihalis Vrekoussis, Maximillien Desservettaz, Michael Pikridas, Elie Bimenyimana, Jonilda Kushta, Matic Ivančič, Martin Rigler, Philippe Goloub, 2023, izvirni znanstveni članek Opis: Abstract. The geographical origin and source apportionment of submicron carbonaceous aerosols (organic aerosols, OAs, and black carbon, BC) have been investigated here for the first time, deploying high time-resolution measurements at an urban background site of Nicosia, the capital
city of Cyprus, in the eastern Mediterranean. This study covers a half-year
period, encompassing both the cold and warm periods with continuous
observations of the physical and chemical properties of PM1 performed
with an Aerosol Chemical Speciation Monitor (ACSM), an aethalometer,
accompanied by a suite of various ancillary offline and online measurements. Carbonaceous aerosols were dominant during both seasons (cold and warm periods), with a contribution of 57 % and 48 % to PM1, respectively, and exhibited recurrent intense nighttime peaks (> 20–30 µg m−3) during the cold period, associated with local domestic heating. The findings of this study show that high concentrations of sulfate (close to 3 µg m−3) were continuously recorded, standing among the highest ever reported for Europe and originating from the Middle East region. Source apportionment of the OA and BC fractions was performed using the
positive matrix factorization (PMF) approach and the combination of two
models (aethalometer model and multilinear regression), respectively. Our
study revealed elevated hydrocarbon-like organic aerosol (HOA)
concentrations in Nicosia (among the highest reported for a European urban
background site), originating from a mixture of local and regional
fossil fuel combustion sources. Although air masses from the Middle East had
a low occurrence and were observed mostly during the cold period, they were
shown to strongly affect the mean concentrations levels of BC and OA in
Nicosia during both seasons. Overall, the present study brings to our
attention the need to further characterize primary and secondary
carbonaceous aerosols in the Middle East, an undersampled region
characterized by continuously increasing fossil fuel (oil and gas) emissions
and extreme environmental conditions, which can contribute to photochemical
ageing.
Ključne besede: PM1, BC, source apportionment, Cyprus, long range transport
Objavljeno v RUNG: 10.05.2024; Ogledov: 134; Prenosov: 2
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