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, original scientific article Abstract: 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.
Keywords: Unmanned Aerial Systems, Cyprus Atmospheric Observatory, eBC, vertical profiling, microaethalometer
Published in RUNG: 13.05.2024; Views: 930; Downloads: 3
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2. Measuring the spatial variability of black carbon in Athens during wintertimeGeorgios Grivas, Iasonas Stavroulas, Eleni Liakakou, Dimitris G. Kaskaoutis, Aikaterini Bougiatioti, D. Paraskevopoulou, Evangelos Gerasopoulos, Nikolaos Mihalopoulos, 2019, original scientific article Abstract: A first assessment of the spatial variability of ambient black carbon (BC) concentrations in the Greater Area of Athens (GAA) was carried out during an intensive wintertime campaign, when ambient levels are exacerbated by increased biomass burning for residential heating. Short-term daytime BC measurements were conducted at 50 sites (traffic and urban/suburban/regional background) and on-road along 12 routes. Daytime measurements were adjusted based on BC concentrations continuously monitored at a reference site. Indicative nighttime BC ambient concentrations were also measured at several residences across the area. Daytime BC concentrations recorded an average of 2.3 μg m-3 with considerable between-site variability. Concentrations at traffic sites were significantly higher (43% on average), compared with the rest of the sites. Varying levels were observed between background site subtypes, with concentrations at urban background sites (located near the center of Athens and the port of Piraeus) being 34% and 114% higher, on average, than at suburban and regional background sites, respectively. The traffic intensity at the nearest road and the population and built density in the surrounding area of sites were recognized as important factors controlling BC levels. On-road concentration measurements (5.4 μg m-3 on average) enabled the identification of hot-spots in the road network, with peak levels encountered along motorways (13.5 μg m-3 on average). Nighttime measurements demonstrated that wintertime BC pollution, enhanced by residential biomass burning for heating, affects the entire Athens basin. The reference site in central Athens was found to be representative of the temporal variability for daytime and nighttime BC concentrations at background locations.
Keywords: mobile measurements, microaethalometer, Athens, mapping, traffic, biomass burning
Published in RUNG: 10.05.2024; Views: 831; Downloads: 8
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