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21.
Performance of microAethalometers: Real-world Field Intercomparisons from Multiple Mobile Measurement Campaigns in Different Atmospheric Environments
Honey Alas, Thomas Mueller, Kay Weinhold, Sascha Pfeifer, Kristina Glojek, Asta Gregorič, Griša Močnik, Luka Drinovec, Francesca Costabile, Martina Ristorini, A. Wiedensohler, 2020, original scientific article

Abstract: Small aethalometers are frequently used to measure equivalent black carbon (eBC) mass concentrations in the context of personal exposure and air pollution mapping through mobile measurements (MM). The most widely used is the microAethalometer (AE51). Its performance in the laboratory and field is well documented, however, there is not sufficient data in the context of its performance in different environments. In this investigation, we present the characterization of the performance of the AE51 through field unit-to-unit intercomparisons (IC), and against a reference absorption photometer from three MM campaigns conducted in drastically different environments. Five IC parameters were considered: i) study area, ii) location of IC, iii) time of day, iv) duration of IC, and v) correction for the filter-loading effect. We can conclude that it is crucial where and how long the IC have been performed in terms of the correlation between the mobile and reference instruments. Better correlations (R2 > 0.8, slope = 0.8) are achieved for IC performed in rural, and background areas for more than 10 minutes. In locations with more homogenous atmosphere, the correction of the loading effect improved the correlation between the mobile and reference instruments. In addition, a newer microAethalometer model (MA200) was characterized in the field under extreme cold conditions and correlated against another MA200 (R2 > 0.8, slope ≈ 1.0), AE51(R2 > 0.9, slope ≈ 0.9), and a stationary Aethalometer (AE33) across all wavelengths (R2 > 0.8, slope ≈ 0.7). For MA200, the loading effect was more pronounced, especially at the lower wavelengths, hence the correction of the loading effect is essential to improve the correlation against the AE33. The MA200 and AE51 proved to be robust and dependable portable instruments for MM applications. Real-world quality assurance of these instruments should be performed through field IC against reference instruments with longer durations in areas of slowly changing eBC concentration.
Keywords: Portable instruments, Mobile monitoring, Black carbon, Instrument intercomparisons
Published in RUNG: 15.09.2020; Views: 2566; Downloads: 183
.pdf Full text (3,54 MB)

22.
Mediterranean Coastal Lagoons: The Importance of Monitoring in Sediments the Biochemical Composition of Organic Matter
Monia Renzi, Francesca Provenza, Sara Pignattelli, Lucrezia Cilenti, Antonietta Specchiulli, Milva Pepi, 2019, original scientific article

Abstract: Transitional water ecosystems are targeted by the European Union (EU) Water Framework Directive (WFD, CE 2000/60) monitoring programs in coastal zones. Concerning sediments, activities performed for the WFD focus on a few variables concerning the biochemical composition of organic matter. Our research reports the effects of oxygen availability on the biochemical composition of organic matter in sediments to highlight levels of targeted variables in time and, according to the depth of sediment layer, both under oxygenated and anoxic conditions in a mesocosm study on sediment cores. Results provide evidence that tested factors of interest (i.e., disturbance type, oxygenic versus anoxic conditions; persistence time of disturbance, 0–14 days; penetration through sedimentary layers, 0–10 cm depth) are able to significantly affect the biochemical composition of organic matter in sediments. Large part of the variables considered in this study (total organic carbon (TOC), total phosphorous (TP), total sulphur (TS), Fe, carbohydrates (CHO), total proteins (PRT), biopolymeric carbon (BPC), chlorophyll-a (Chl-a) are significantly affected and correlated to the oxygenation levels and could be good early indicators of important changes of environmental conditions. Monitoring activities performed under WFD guidelines and management strategies of Mediterranean coastal lagoon ecosystems shall include the biochemical composition of organic matter in sediment to provide an exhaustive picture of such dynamic ecosystems.
Keywords: decomposition, transitional water ecosystems, organic loads, mesocosm, monitoring programs
Published in RUNG: 20.04.2020; Views: 2734; Downloads: 0
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