Transport and transformation of atmospheric aerosol across Central Europe with emphasis on anthropogenic sources

<p>The trend in PM<sub>10</sub> concentrations in Europe has stagnated over the last two decades, showing only limited annual changes even though there are continued reductions in PM emissions. Possible reasons could be linked to both the aging processes of the particles in the atmosphere and their long-range transport. Therefore, better understanding the multiple origins of the atmospheric aerosol, their sources apportionment at different places are necessary for the development of efficient mitigation strategies. The ultimate objective of the project TRACE is to assess the transport and transformation of atmospheric aerosol across Central Europe with emphasis on anthropogenic sources (including coal and wood combustion) using synergic measurement methods (offline and online) and state-of-the art modelling tools including receptor-oriented models and Chemical transport models. Measurements were performed during winter and summer periods in 2021 simultaneously at three sampling places (Melpitz, DE, Kosetice, CZ, and Frydland, CZ) using state-of-the-art online and offline comprehensive chemical characterization of the atmospheric aerosol. Preliminary results from Scanning Mobility Particle Sizer (SMPS) showed peaks as high as 50 µg/m³ mass concentration during a dust event. Moreover, results from Aerosol Mass Spectrometer (AMS) and receptor modeling (RF) via Positive Matrix Factorization (PMF) from the winter campaign will be presented. </p>

MoloVol: an easy-to-use program to calculate various volumes and surface areas of chemical structures and identify cavities

Cavities are a ubiquitous feature of chemical structures encountered in various fields ranging from supramolecular chemistry to molecular biology. They are involved in the encapsulation, transport, and transformation of guest molecules, thus necessitating a precise and accessible tool for estimating and visualizing their size and shape. MoloVol, a free, user-parametrizable, open-source software, developed for calculating a range of geometric features for both unit cell and isolated structures is presented here. MoloVol utilizes up to two spherical probes to define cavities, surfaces, and volumes. The program was optimized by combining an octree data structure with voxel-partitioned space allowing for even high-resolution protein structure calculations at reasonable timescales. MoloVol comes with a user-friendly graphic interface along with a command line interface for high throughput calculations. It was written in C++ and is available on Windows, macOS, and Linux distributions.

Folic Acid Absorption Characteristics and Effect on Cecal Microbiota of Laying Hens

This experiment was conducted to investigate the characteristics of folic acid (FA) absorption in laying hens and the effect of FA supplementation on cecal microbiota. A total of 432 healthy hens (30-week-old) were randomly assigned to four diets supplemented with FA: 0, 1, 6, and 24 mg/kg of feed for 8 w. Blood, duodenum, jejunum, ileum, cecum, and cecal chyme samples (six samples per treatment) were collected from the hens at the end of the feeding trial. Expression profiles of folate transport and transformation genes in intestine and cecal microbiota were detected. Results showed that serum folate level significantly increased (P < 0.01) with an increase in dietary FA supplementation, reaching a plateau at 6 mg/kg FA supplementation. The expression of FA transport and transformation genes was not affected in the cecum (P > 0.05) by dietary FA supplementation; however, it was affected in the duodenum, jejunum, and ileum and mostly showed a downward trend in treatment groups (P < 0.05). The genes affected include duodenal folate receptor (Folr) and dihydrofolate reductase (Dhfr), jejunal proton-coupled folate transporter (Pcft) and reduced folate carrier (Rfc), and ileal ATP binding cassette subfamily C member (Abcc2), Abcc3, Rfc, Folr, and Dhfr. Furthermore, according to the operational taxonomic unit classification and taxonomic position identification, the cecal microbiota population of the hens was not affected by dietary FA supplementation at the phylum, class, order, family, genus, and species levels (P > 0.05). However, the relative abundance of some microbiota was affected by dietary FA supplementation (P < 0.05). In conclusion, FA transport from the intestinal lumen into enterocytes, and then into the bloodstream, is strictly regulated, which may be associated with the regulation of the expression profiles of genes involved in FA absorption. Pathogenic bacteria decreased in the cecum, especially at 24 mg/kg supplementation, but the beneficial bacteria (Bifidobacteriaceae) decreased at this level, too. Overall, FA supplementation at 6 mg/kg, which was selected for folate-enriched egg production, did not affect the health and metabolism of laying hens negatively.

Overview: On the transport and transformation of pollutants in the outflow of major population centres – observational data from the EMeRGe European intensive operational period in summer 2017

EMeRGe (Effect of Megacities on the transport and transformation of pollutants on the Regional to Global scales) is an international project focusing on atmospheric chemistry, dynamics and transport of local and regional pollution originating in megacities and other major population centres (MPCs). Airborne measurements, taking advantage of the long range capabilities of the HALO research platform (High Altitude and Long range research aircraft, www.halo-spp.de), are a central part of the research project. In order to provide an adequate set of measurements at different spatial scales, two field experiments were positioned in time and space to contrast situations when the photochemical transformation of plumes emerging from MPCs is large. These experiments were conducted in summer 2017 over Europe and in the inter-monsoon period over Asia in spring 2018. The intensive observational periods (IOP) involved HALO airborne measurements of ozone and its precursors, volatile organic compounds, aerosol particles and related species as well as coordinated ground-based ancillary observations at different sites. Perfluorocarbon (PFC) tracer releases and model forecasts supported the flight planning and the identification of pollution plumes. This paper describes the experimental deployment of the IOP in Europe, which comprised 7 HALO research flights with aircraft base in Oberpfaffenhofen (Germany) for a total of 53 flight hours. The MPC targets London (Great Britain), Benelux/Ruhr area (Belgium, The Netherlands, Luxembourg and Germany), Paris (France), Rome and Po Valley (Italy), Madrid and Barcelona (Spain) were investigated. An in-flight comparison of HALO with the collaborating UK-airborne platform FAAM took place to assure accuracy and comparability of the instrumentation on-board. Generally, significant enhancement of trace gases and aerosol particles are attributed to emissions originating in MPCs at distances of hundreds of kilometres from the sources. The proximity of different MPCs over Europe favours the mixing of plumes of different origin and level of processing and hampers the unambiguous attribution of the MPC sources. Similarly, urban plumes mix efficiently with natural sources as desert dust and with biomass burning emissions from vegetation and forest fires. This confirms the importance of wildland fire emissions in Europe and indicates an important but discontinuous contribution to the European emission budget that might be of relevance in the design of efficient mitigation strategies. The synergistic use and consistent interpretation of observational data sets of different spatial and temporal resolution (e.g. from ground-based networks, airborne campaigns, and satellite measurements) supported by modelling within EMeRGe, provides a unique insight to test the current understanding of MPC pollution outflows. The present work provides an overview of the most salient results and scientific questions in the European context, these being addressed in more detail within additional dedicated EMeRGe studies. The deployment and results obtained in Asia will be the subject of separate publications.

Simulating Water and Pollution Exports from Soil to Stream during the Thawing Period at the Small River Basin Scale

A physical model was developed to describe the soil-to-stream export processes of water and pollutants in a small river basin during the soil thawing period. The hydrological and pollution transport and transformation behaviors in paddy- and corn-dominated catchments were numerically simulated; the impacts of the pollution concentrations, interactions between the migrated water and pollutants in the soil, and pollutant transformations during the pollution export were coupled. Experimental field data from the Heidingzi river basin during the soil thawing period were used to calibrate the model parameters and evaluate the performance. The mass of the dissolved pollutants from soil particles in the migrated soil pore water was the key factor affecting the pollution export into the streams; the water content directly affected the pollution export. The concentration of the pollutants peaked when the initial exported water was high. The pollutant transport processes influenced the pollution export more significantly after the soil water was significantly reduced. The N-S efficiency coefficients between the simulated and monitored flow rates and the pollution concentrations at the outlets of the paddy- and corn-dominated catchments were >0.60 and >0.54, respectively. The system deviations between the simulated and monitored flow rates and the pollution concentrations were <10% and <15%, respectively. The proposed model effectively described the water flow, pollution transport and transformation processes.

Advances in Environmental Hydraulics

Environmental Hydraulics (EH) is the scientific study of environmental water flows and their related transport and transformation processes affecting the environmental quality of natural water systems, such as rivers, lakes, and aquifers, on our planet Earth [...]