Gå til innhold
  • Send

  • Kategori

  • Sorter etter

  • Antall per side

Fant 842 publikasjoner. Viser side 31 av 36:

Publikasjon  
År  
Kategori

Thymidine Kinase+/− Mammalian Cell Mutagenicity Assays for Assessment of Nanomaterials

Chen, Tao; Dusinska, Maria; Elespuru, Rosalie K.

The methods outlined here are part of a series of papers designed specifically for genotoxicity assessment of nanomaterials (NM). Common Considerations such as NM characterization, sample preparation and dose selection, relevant to all genotoxicity assays, are found in an accompanying paper. The present paper describes methods for evaluation of mutagenicity in the mammalian (mouse) thymidine kinase (Tk) gene occurring in L5178Y mouse lymphoma (ML) cells and in the designated TK gene in human lymphoblastoid TK6 cells. Mutations change the functional genotype from TK+/− to TK−/−, detectable as cells surviving on media selective for the lack of thymidine kinase (TK) function. Unlike cells with TK enzyme function, the TK−/− cells are unable to integrate the toxic selection agent, allowing these cells to survive as rare mutant colonies. The ML assay has been shown to detect a broad spectrum of genetic damage, including both small scale (point) mutations and chromosomal alterations. This assay is a widely used mammalian cell gene mutation assay for regulatory purposes and is included in the core battery of genotoxicity tests for regulatory decision-making. The TK6 assay is an assay using a human cell line derived similarly via mutagenic manipulations and optimal selection. Details are provided on the materials required, cell culture methods, selection of test chemical concentrations, cytotoxicity, treatment time, mutation expression, cloning, and data calculation and interpretation. The methods describe the microwell plate version of the assays without metabolic activation.

2022

Thermodynamic and electron paramagnetic resonance descriptors of TiO2 nanoforms interaction with plasma albumin: The interplay between energetic parameters and nanomaterial's toxicity

Gheorghe, Daniela; Precupas, Aurica; Botea-Petcu, Alina; Sandu, Romica; Teodorescu, Florina; Leonties, Anca Ruxandra; Popa, Vlad Tudor; Matei, Iulia; Ionita, Gabriela; Yamani, Naouale El; Ostermann, Melanie; Sauter, Alexander; Jensen, Keld Alstrup; Cimpan, Mihaela Roxana; Rundén-Pran, Elise; Dusinska, Maria; Tanasescu, Speranta

2025

Thermal conditions during heat waves of a mid-European metropolis under consideration of climate change, urban development scenarios and resilience measures for the mid-21st century

Trimmel, Heidelinde; Weihs, Philipp; Faroux, Stephanie; Formayer, Herbert; Hamer, Paul David; Hasel, Kristoffer; Laimighofer, Johannes; Leidinger, David; Masson, Valery; Nadeem, Imran; Oswald, Sandro M.; Revesz, Michael; Schoetter, Robert

In this study we produce two urban development scenarios estimating potential urban sprawl and optimized development concerning building construction, and we simulate their influence on air temperature, surface temperatures and human thermal comfort. We select two heat waves representative for present and future conditions of the mid 21st century and simulations are run with the Town Energy Balance Model (TEB) coupled online and offline to the Weather Research and Forecasting Model (WRF). Global and regional climate change under the RCP8.5 scenario causes an increase of daily maximum air temperature in Vienna by 7 K. The daily minimum air temperature will increase by 2–4 K. Changes caused by urban growth or densification mainly affect air temperature and human thermal comfort locally where new urbanisation takes place and does not occur significantly in the central districts. A combination of near zero-energy standards and increasing albedo of building materials on the city scale accomplishes a maximum reduction of urban canyon temperature achieved by changes in urban parameters of 0.9 K for the minima and 0.2 K for the maxima. Local scale changes of different adaptation measures show that insulation of buildings alone increases the maximum wall surface temperatures by more than 10 K or the maximum mean radiant temperature (MRT) in the canyon by 5 K. Therefore, measures to reduce MRT within the urban canyons like tree shade are needed to complement the proposed measures. This study concludes that the rising air temperatures expected by climate change puts an unprecedented heat burden on Viennese inhabitants, which cannot easily be reduced by measures concerning buildings within the city itself. Additionally, measures such as planting trees to provide shade, regional water sensitive planning and global reduction of greenhouse gas emissions in order to reduce temperature extremes are required.

2019

Emissions of Tetrafluoromethane (CF4) and Hexafluoroethane (C2F6) From East Asia: 2008 to 2019

Kim, Jooil; Thompson, Rona Louise; Park, Hyeri; Bogle, Stephanie; Mühle, Jens; Park, Mi-Kyung; Kim, Yeaseul; Harth, Christina M.; Salameh, Peter K.; Schmidt, Roland; Ottinger, Deborah; Park, Sunyoung; Weiss, Ray F.

The perfluorocarbons (PFCs), tetrafluoromethane (CF4) and hexafluoroethane (C2F6), are potent greenhouse gases with very long atmospheric lifetimes. They are emitted almost entirely from industrial sources, including the aluminum and rare earth metal smelting industries that emit them as by-products, and the semiconductor and flat panel display manufacturing industries that use them and vent unutilized amounts to the atmosphere. Despite extensive industrial efforts to quantify and curb these emissions, “top-down” PFC emission estimates derived from atmospheric measurements continue to rise and are significantly greater than reported process- and inventory-based “bottom-up” emissions. In this study, we estimate emissions of CF4 and C2F6 from East Asia, where PFC emitting industries are heavily concentrated, using a top-down approach (a Bayesian inversion) with high-frequency atmospheric measurements at Gosan (Jeju Island, South Korea) for 2008–2019. We also compile and analyze the available bottom-up CF4 and C2F6 emissions in East Asia from industrial and government reports. Our results suggest that the observed increases in global PFC emissions since 2015 are driven primarily by China's aluminum industry, with significant contributions from Japan's and Korea's semiconductor industry. Our analysis suggests that Chinese emissions occur predominantly from the aluminum industry, although their emissions per production ratio may be improving. Our results for Japan and Korea find significant discrepancies between top-down and bottom-up emissions estimates, suggesting that the effectiveness of emission reduction systems (abatement) used in their semiconductor industries may be overestimated. Overall, our top-down results for East Asia contribute significantly to reducing the gap in the global PFC emission budgets.

2021

Distinct pathways associated with chromosomal aberration frequency in a cohort exposed to genotoxic compounds compared to general population

Niazi, Yasmeen; Thomsen, Hauke; Smolkova, Bozena; Vodickova, Ludmila; Vodenkova, Sona; Kroupa, Michal; Vymetalkova, Veronika; Kazimirova, Alena; Barancokova, Magdalena; Volkovova, Katarina; Staruchova, Marta; Hoffmann, Per; Nöthen, Markus M.; Dusinska, Maria; Musak, Ludovit; Vodička, Pavel; Hemminki, Kari; Försti, Asta

2019

Energetic particle precipitation influences global secondary ozone distribution

Jia, Jia; Murberg, Lise Eder; Løvset, Tiril; Orsolini, Yvan; Espy, Patrick Joseph; Zeller, Lilou C. G.; Salinas, Cornelius Csar Jude H.; Lee, Jae N.; Wu, Dong; Zhang, Jiarong

The secondary ozone layer is a global peak in ozone abundance in the upper mesosphere-lower thermosphere (UMLT) around 90-95 km. The effect of energetic particle precipitation (EPP) from geomagnetic processes on this UMLT ozone remains largely unexplored. In this research we investigated how the secondary ozone responds to EPP using satellite observations. In addition, the residual Mean Meridional Circulation (MMC) derived from model simulations and the atomic oxygen [O], atomic hydrogen [H], temperature measurements from satellite observations were used to characterise the residual circulation changes during EPP events. We report regions of secondary ozone enhancement or deficit across low, mid and high latitudes as a result of global circulation and transport changes induced by EPP. The results are supported by a sensitivity test using an empirical model.

2024

Estimating tropospheric and stratospheric winds using infrasound from explosions

Blixt, Erik Mårten; Näsholm, Sven Peter; Gibbons, Steven John; Evers, Laslo; Charlton-Perez, Andrew; Orsolini, Yvan; Kværna, Tormod

The receiver-to-source backazimuth of atmospheric infrasound signals is biased when cross-winds are present along the propagation path. Infrasound from 598 surface explosions from over 30 years in northern Finland is measured with high spatial resolution on an array 178 km almost due North. The array is situated in the classical shadow-zone distance from the explosions. However, strong infrasound is almost always observed, which is most plausibly due to partial reflections from stratospheric altitudes. The most probable propagation paths are subject to both tropospheric and stratospheric cross-winds, and the wave-propagation modelling in this study yields good correspondence between the observed backazimuth deviation and cross-winds from the European Centre for Medium-Range Weather Forecasts Reanalysis (ERA)-Interim reanalysis product. This study demonstrates that atmospheric cross-winds can be estimated directly from infrasound data using propagation time and backazimuth deviation observations. This study finds these cross-wind estimates to be in good agreement with the ERA-Interim reanalysis.

2019

The Community Inversion Framework v1.0: a unified system for atmospheric inversion studies

Berchet, Antoine; Sollum, Espen; Thompson, Rona Louise; Pison, Isabelle; Thanwerdas, Joel; Broquet, Grégoire; Chevallier, Frédéric; Aalto, Tuula; Berchet, Adrien; Bergamaschi, Peter; Brunner, Dominik; Engelen, Richard; Fortems-Cheiney, Audrey; Gerbig, Christoph; Zwaaftink, Christine Groot; Haussaire, Jean-Matthieu; Henne, Stephan; Houweling, Sanne; Karstens, Ute; Kutsch, Werner L.; Luijkx, Ingrid T.; Monteil, Guillaume; Palmer, Paul I.; Peet, Jacob C. A. van; Peters, Wouter; Peylin, Philippe; Potier, Elise; Rödenbeck, Christian; Saunois, Marielle; Scholze, Marko; Tsuruta, Aki; Zhao, Yuanhong

Atmospheric inversion approaches are expected to play a critical role in future observation-based monitoring systems for surface fluxes of greenhouse gases (GHGs), pollutants and other trace gases. In the past decade, the research community has developed various inversion software, mainly using variational or ensemble Bayesian optimization methods, with various assumptions on uncertainty structures and prior information and with various atmospheric chemistry–transport models. Each of them can assimilate some or all of the available observation streams for its domain area of interest: flask samples, in situ measurements or satellite observations. Although referenced in peer-reviewed publications and usually accessible across the research community, most systems are not at the level of transparency, flexibility and accessibility needed to provide the scientific community and policy makers with a comprehensive and robust view of the uncertainties associated with the inverse estimation of GHG and reactive species fluxes. Furthermore, their development, usually carried out by individual research institutes, may in the future not keep pace with the increasing scientific needs and technical possibilities. We present here the Community Inversion Framework (CIF) to help rationalize development efforts and leverage the strengths of individual inversion systems into a comprehensive framework. The CIF is primarily a programming protocol to allow various inversion bricks to be exchanged among researchers. In practice, the ensemble of bricks makes a flexible, transparent and open-source Python-based tool to estimate the fluxes of various GHGs and reactive species both at the global and regional scales. It will allow for running different atmospheric transport models, different observation streams and different data assimilation approaches. This adaptability will allow for a comprehensive assessment of uncertainty in a fully consistent framework. We present here the main structure and functionalities of the system, and we demonstrate how it operates in a simple academic case.

2021

The superstatistical nature and interoccurrence time of atmospheric mercury concentration fluctuations

Carbone, Francesco; Bruno, Antonio Giovanni; Naccarato, Attilio; Simone, Francesco De; Gencarelli, Christian Natale; Sprovieri, F.; Hedgecock, I. M.; Landis, Matthew S.; Skov, Henrik; Pfaffhuber, Katrine A.; Read, Katie A.; Martin, Lywill G.; Angot, Hélène; Dommergue, Aurélien; Magand, O.; Pirrone, N.

2018

Perfluorocyclobutane (PFC-318, c-C4F8) in the global atmosphere

Mühle, Jens; Trudinger, Cathy; Western, Luke M.; Rigby, Matthew; Vollmer, Martin K.; Park, Sunyoung; Manning, Alistair J.; Say, Daniel; Ganesan, Anita; Steele, L. Paul; Ivy, Diane J.; Arnold, Tim; Li, Shanlan; Stohl, Andreas; Harth, Christina M.; Salameh, Peter K.; McCulloch, Archie; O'Doherty, Simon; Park, Mi-Kyung; Jo, Chun Ok; Young, Dickon; Stanley, Kieran; Krummel, Paul B.; Mitrevski, Blagoj; Hermansen, Ove; Lunder, Chris Rene; Evangeliou, Nikolaos; Yao, Bo; Kim, Jooil; Hmiel, Benjamin; Buizert, Christo; Petrenko, Vasilii V.; Arduini, Jgor; Maione, Michela; Etheridge, David M.; Michalopoulou, Eleni; Czerniak, Mike; Severinghaus, Jeffrey P.; Reimann, Stefan; Simmonds, Peter G.; Fraser, Paul J.; Prinn, Ronald G.; Weiss, Ray F.

We reconstruct atmospheric abundances of the potent greenhouse gas c-C4F8 (perfluorocyclobutane, perfluorocarbon PFC-318) from measurements of in situ, archived, firn, and aircraft air samples with precisions of ∼1 %–2 % reported on the SIO-14 gravimetric calibration scale. Combined with inverse methods, we found near-zero atmospheric abundances from the early 1900s to the early 1960s, after which they rose sharply, reaching 1.66 ppt (parts per trillion dry-air mole fraction) in 2017. Global c-C4F8 emissions rose from near zero in the 1960s to 1.2±0.1 (1σ) Gg yr−1 in the late 1970s to late 1980s, then declined to 0.77±0.03 Gg yr−1 in the mid-1990s to early 2000s, followed by a rise since the early 2000s to 2.20±0.05 Gg yr−1 in 2017. These emissions are significantly larger than inventory-based emission estimates. Estimated emissions from eastern Asia rose from 0.36 Gg yr−1 in 2010 to 0.73 Gg yr−1 in 2016 and 2017, 31 % of global emissions, mostly from eastern China. We estimate emissions of 0.14 Gg yr−1 from northern and central India in 2016 and find evidence for significant emissions from Russia. In contrast, recent emissions from northwestern Europe and Australia are estimated to be small (≤1 % each). We suggest that emissions from China, India, and Russia are likely related to production of polytetrafluoroethylene (PTFE, “Teflon”) and other fluoropolymers and fluorochemicals that are based on the pyrolysis of hydrochlorofluorocarbon HCFC-22 (CHClF2) in which c-C4F8 is a known by-product. The semiconductor sector, where c-C4F8 is used, is estimated to be a small source, at least in South Korea, Japan, Taiwan, and Europe. Without an obvious correlation with population density, incineration of waste-containing fluoropolymers is probably a minor source, and we find no evidence of emissions from electrolytic production of aluminum in Australia. While many possible emissive uses of c-C4F8 are known and though we cannot categorically exclude unknown sources, the start of significant emissions may well be related to the advent of commercial PTFE production in 1947. Process controls or abatement to reduce the c-C4F8 by-product were probably not in place in the early decades, explaining the increase in emissions in the 1960s and 1970s. With the advent of by-product reporting requirements to the United Nations Framework Convention on Climate Change (UNFCCC) in the 1990s, concern about climate change and product stewardship, abatement, and perhaps the collection of c-C4F8 by-product for use in the semiconductor industry where it can be easily abated, it is conceivable that emissions in developed countries were stabilized and then reduced, explaining the observed emission reduction in the 1980s and 1990s. Concurrently, production of PTFE in China began to increase rapidly. Without emission reduction requirements, it is plausible that global emissions today are dominated by China and other developing countries. We predict that c-C4F8 emissions will continue to rise and that c-C4F8 will become the second most important emitted PFC in terms of CO2-equivalent emissions within a year or two. The 2017 radiative forcing of c-C4F8 (0.52 mW m−2) is small but emissions of c-C4F8 and other PFCs, due to their very long atmospheric lifetimes, essentially permanently alter Earth's radiative budget and should be reduced. Significant emissions inferred outside of the investigated regions clearly show that observational capabilities and reporting requirements need to be improved to understand global and country-scale emissions of PFCs and other synthetic greenhouse gases and ozone-depleting substances.

2019

A roadmap to estimating agricultural ammonia volatilization over Europe using satellite observations and simulation data

Abeed, Rimal; Viatte, Camille; Porter, William C.; Evangeliou, Nikolaos; Clerbaux, Cathy; Clarisse, Lieven; Damme, Martin Van; Coheur, Pierre-François; Safieddine, Sarah

Ammonia (NH3) is one of the most important gases emitted from agricultural practices. It affects air quality and the overall climate and is in turn influenced by long-term climate trends as well as by short-term fluctuations in local and regional meteorology. Previous studies have established the capability of the Infrared Atmospheric Sounding Interferometer (IASI) series of instruments, aboard the Metop satellites, to measure ammonia from space since 2007. In this study, we explore the interactions between atmospheric ammonia, land and meteorological variability, and long-term climate trends in Europe. We investigate the emission potential (Γsoil) of ammonia from the soil, which describes the soil–atmosphere ammonia exchange. Γsoil is generally calculated in-field or in laboratory experiments; here, and for the first time, we investigate a method which assesses it remotely using satellite data, reanalysis data products, and model simulations.

We focus on ammonia emission potential in March 2011, which marks the start of growing season in Europe. Our results show that Γsoil ranges from 2 × 103 to 9.5 × 104 (dimensionless) in fertilized cropland, such as in the North European Plain, and is of the order of 10–102 in a non-fertilized soil (e.g., forest and grassland). These results agree with in-field measurements from the literature, suggesting that our method can be used in other seasons and regions in the world. However, some improvements are needed in the determination of mass transfer coefficient k (m s−1), which is a crucial parameter to derive Γsoil.

Using a climate model, we estimate the expected increase in ammonia columns by the end of the century based on the increase in skin temperature (Tskin), under two different climate scenarios. Ammonia columns are projected to increase by up to 50 %, particularly in eastern Europe, under the SSP2-4.5 scenario and might even double (increase of 100 %) under the SSP5-8.5 scenario. The increase in skin temperature is responsible for a formation of new hotspots of ammonia in Belarus, Ukraine, Hungary, Moldova, parts of Romania, and Switzerland.

2023

Costs and benefits of implementing an Environmental Speed Limit in a Nordic city

Lopez-Aparicio, Susana; Grythe, Henrik; Thorne, Rebecca Jayne; Vogt, Matthias

We present a comprehensive study on the impacts and associated changes in costs resulting from the implementation of Environmental Speed Limits (ESLs), as a measure to reduce PM10 and associated health effects. We present detailed modelled emissions (i.e., CO2, NOx, PM2.5 and PM10), concentration levels (i.e., PM2.5 and PM10) and population exposure to PM2.5 and PM10 under three scenarios of ESL implementation for the Metropolitan Area of Oslo. We find that whilst emissions of NOx and CO2 do not seem to show significant changes with ESL implementation, PM10 emissions are reduced by 6–12% and annual concentration levels are reduced up to 8%, with a subsequent reduction in population exposure. The modelled data is used to carry out a detailed analysis to quantify the changes in private and social costs for the roads in Oslo where ESL are implemented today. This involves assessments related to human health, climate, fuel consumption, time losses and the incidence of traffic accidents. For a scenario using actual speed data from ESL implementation, our study shows a net benefit associated with the implementation of ESLs, whilst for a theoretical scenario with strict speed limit compliance we find a net increase in costs. This is largely due to variation in costs due to time losses between the scenarios, although uncertainties are high.

2020

Aircraft-based mass balance estimate of methane emissions from offshore gas facilities in the southern North Sea

Pühl, Magdalena; Roiger, Anke; Fiehn, Alina; Negron, Alan M. Gorchov; Kort, Eric A.; Schwietzke, Stefan; Pisso, Ignacio; Foulds, Amy; Lee, James; France, James L.; Jones, Anna E.; Lowry, Dave; Fisher, Rebecca E.; Huang, Langwen; Shaw, Jacob; Bateson, Prudence; Andrews, Stephen; Young, Stuart; Dominutti, Pamela; Lachlan-Cope, Tom; Weiss, Alexandra; Allen, Grant

Atmospheric methane (CH4) concentrations have more than doubled since the beginning of the industrial age, making CH4 the second most important anthropogenic greenhouse gas after carbon dioxide (CO2). The oil and gas sector represents one of the major anthropogenic CH4 emitters as it is estimated to account for 22 % of global anthropogenic CH4 emissions. An airborne field campaign was conducted in April–May 2019 to study CH4 emissions from offshore gas facilities in the southern North Sea with the aim of deriving emission estimates using a top-down (measurement-led) approach. We present CH4 fluxes for six UK and five Dutch offshore platforms or platform complexes using the well-established mass balance flux method. We identify specific gas production emissions and emission processes (venting and fugitive or flaring and combustion) using observations of co-emitted ethane (C2H6) and CO2. We compare our top-down estimated fluxes with a ship-based top-down study in the Dutch sector and with bottom-up estimates from a globally gridded annual inventory, UK national annual point-source inventories, and operator-based reporting for individual Dutch facilities. In this study, we find that all the inventories, except for the operator-based facility-level reporting, underestimate measured emissions, with the largest discrepancy observed with the globally gridded inventory. Individual facility reporting, as available for Dutch sites for the specific survey date, shows better agreement with our measurement-based estimates. For all the sampled Dutch installations together, we find that our estimated flux of (122.9 ± 36.8) kg h−1 deviates by a factor of 0.64 (0.33–12) from reported values (192.8 kg h−1). Comparisons with aircraft observations in two other offshore regions (the Norwegian Sea and the Gulf of Mexico) show that measured, absolute facility-level emission rates agree with the general distribution found in other offshore basins despite different production types (oil, gas) and gas production rates, which vary by 2 orders of magnitude. Therefore, mitigation is warranted equally across geographies.

2024

How idling and maneuvering affect air quality: Case study of school commutes

Grythe, Henrik; Nicińska, Anna; Drabicki, Arkadiusz; Santos, Gabriela Sousa

2025

Cleaning costs for European sheltered white painted steel and modern glass surfaces due to air pollution since the year 2000

Grøntoft, Terje; Verney-Carron, Aurelie; Tidblad, Johan

This paper reports estimated maintenance-cleaning costs, cost savings and cleaning interval increases for structural surfaces and windows in Europe obtainable by reducing the air pollution. Methodology and data from the ICP-materials project were used. The average present (2018) cleaning costs for sheltered white painted steel surfaces and modern glass due to air pollution over background, was estimated to be ~2.5 Euro/m2∙year. Hypothetical 50% reduction in the air pollution was found to give savings in these cleaning costs of ~1.5 Euro/m2∙year. Observed reduction in the air pollution, from 2002–2005 until 2011–2014, have probably increased the cleaning interval for white painted steel with ~100% (from 12 to 24 years), representing reductions in the single intervention cleaning costs from 7 to 4%/year (= % of one cleaning investment, per year during the cleaning interval) and for the modern glass with ~65% (from 0.85 to 1.3 years), representing reductions in the cleaning cost from 124 to 95%/year. The cleaning cost reductions, obtainable by 50% reduction in air pollution, would have been ~3 %/year for white painted steel and ~60%/year for the modern glass, representing ~100 and 50% additional cleaning interval increases. These potential cleaning cost savings are significantly higher than previously reported for the weathering of Portland limestone ornament and zinc monuments.

2019

The alamar blue assay in the context of safety testing of nanomaterials

Longhin, Eleonora Marta; Yamani, Naouale El; Rundén-Pran, Elise; Dusinska, Maria

The Alamar Blue (AB) assay is widely used to investigate cytotoxicity, cell proliferation and cellular metabolic activity within different fields of toxicology. The use of the assay with nanomaterials (NMs) entails specific aspects including the potential interference of NMs with the test. The procedure of the AB assay applied for testing NMs is described in detail and step-by-step, from NM preparation, cell exposure, inclusion of interference controls, to the analysis and interpretation of the results. Provided that the proper procedure is followed, and relevant controls are included, the AB assay is a reliable and high throughput test to evaluate the cytotoxicity/proliferation/metabolic response of cells exposed to NMs.

2022

Spatial Source Contribution and Interannual Variation in Deposition of Dust Aerosols Over the Chinese Loess Plateau

Haugvaldstad, Ove Westermoen; Tang, Hui; Kaakinen, Anu; Bohm, Katja; Zwaaftink, Christine Groot; Grythe, Henrik; Stevens, Thomas; Zhang, Zhongshi; Stordal, Frode

The Chinese Loess Plateau (CLP) in northern China is home to one of the most prominent loess records in the world, reflecting past eolian dust activity in East Asia. However, their interpretation is hampered by ambiguity in the origin of loess-forming dust and an incomplete understanding of the circulation forcing dust accumulation. In this study, we used a novel modeling approach combining a dust emission model FLEXDUST with simulated back trajectories from FLEXPART to trace the dust back to where it was emitted. Over 21 years (1999–2019), we modeled back trajectories for fine (∼2 μm) and super-coarse (∼20 μm) dust particles at six CLP sites during the peak dust storm season from March to May. FLEXPART source-receptor relationships are combined with the dust emission inventory from FLEXDUST to create site-dependent high-resolution maps of the source contribution of deposited dust. The nearby dust emission areas were found to be the main source of dust to the CLP. Dust deposition across the CLP was found to predominantly occur via wet removal, with also some super-coarse dust from distant emission regions being wet deposited following high-level tropospheric transport. The high topography located on the downwind side of the emission area plays an essential role in forcing the emitted super-coarse dust upward. On an interannual scale, the phase of the Arctic Oscillation in the preceding winter was found to have a strong association with the spring deposition rate on the CLP, while the strength of the East Asian Winter Monsoon was less influential.

2024

In vivo Mammalian Alkaline Comet Assay: Method Adapted for Genotoxicity Assessment of Nanomaterials

Cardoso, Renato; Dusinska, Maria; Collins, Andrew Richard; Manjanatha, Mugamane; Pfuhler, Stefan; Registre, Marilyn; Elespuru, Rosalie K.

The in vivo Comet assay measures the generation of DNA strand breaks under conditions in which the DNA will unwind and migrate to the anode in an electrophoresis assay, producing comet-like figures. Measurements are on single cells, which allows the sampling of a diversity of cells and tissues for DNA damaging effects. The Comet assay is the most common in vivo method for genotoxicity assessment of nanomaterials (NM). The Method outlined here includes a recommended step-by-step approach, consistent with OECD 489, taking into consideration the issues impacting assessment of NM, including choice of cells or systems, handling of NM test articles, dose determination, assay methods and data assessment. This method is designed to be used along with the accompanying “Common Considerations” paper, which discusses issues common to any genotoxicity assay using NM as a test article.

2022

Advancing Genotoxicity Assessment by Building a Global AOP Network

Demuynck, Emmanuel; Vanhaecke, Tamara; Thienpont, Anouck; Cappoen, Davie; Goethem, Freddy Van; Winkelman, L. M. T.; Beltman, Joost B.; Murugadoss, Sivakumar; Olsen, Ann-Karin Hardie; Marcon, Francesca; Bossa, Cecilia; Shaikh, Sanah M.; Nikolopoulou, Dimitra; Hatzi, Vasiliki; Pennings, Jeroen L A; Luijten, Mirjam; Adam-Guillermin, Christelle; Paparella, Martin; Audebert, Marc; Mertens, Birgit

2025

Supervised Anomaly Detection in Univariate Time-Series Using 1D Convolutional Siamese Networks

Chatterjee, Ayan; Thambawita, Vajira L B; Riegler, Michael; Halvorsen, Pål

In time-series data analysis, identifying anomalies is crucial for maintaining data integrity and ensuring accurate analyses and decision-making. Anomalies can compromise data quality and operational efficiency. The complexity of time-series data, with its temporal dependencies and potential non-stationarity, makes anomaly detection challenging but essential. Our research introduces ADSiamNet, a 1D Convolutional Neural Network-based Siamese network model for anomaly detection and rectification. ADSiamNet effectively identifies localized patterns in time-series data and smooths detected anomalies using a quantile-based technique. In tests with physical activity data from Actigraph watches and MOX2-5 sensors, ADSiamNet achieved accuracies of 98.65% and 85.0%, respectively, outperforming other supervised anomaly detection methods. The model uses a contrastive loss function to compare input sequences and adjusts network weights iteratively during training to recognize intricate patterns. Additionally, we evaluated various univariate time-series forecasting algorithms on datasets with and without anomalies. Results show that anomaly-smoothed data reduces forecasting errors, highlighting our approach’s effectiveness in enhancing time-series data analysis’s integrity and reliability. Future research will focus on multivariate time-series datasets.

2025

Are ingredients of personal care products likely to undergo long-range transport to remote regions?

Vecchiato, Marco; Breivik, Knut

Personal care products (PCPs) contain contaminants of emerging concern. Despite increasing reports of their presence in polar regions, the behavior of PCP ingredients under cold environmental conditions remains poorly understood. Snow collected around Villum Research Station at Station Nord, Greenland, between December 2018 and June 2019 was extracted in a stainless steel clean-room and analyzed for seven fragrance materials, four organic UV-filters and an antioxidant using gas chromatography-tandem mass spectrometry. All twelve target PCPs were detected, with elevated concentrations during two sampling events potentially tied to air mass transport from northern Europe and the northern coasts of Russia. To contextualize the presence of these PCP chemicals in high Arctic snow, we estimated their (i) partitioning properties as a function of temperature, (ii) equilibrium phase distribution and dominant deposition processes in the atmosphere at temperatures above and below freezing, and (iii) potential for long-range environmental transport (LRET). Even though most PCPs are deemed to be gas phase chemicals predominantly deposited as vapors, rapid atmospheric degradation is expected to limit their LRET. On the other hand, the less volatile octocrylene is expected to be sorbed to atmospheric particles, removed via wet and dry particle deposition, and possibly exhibit a higher potential for LRET by being protected from attack by photooxidants. The contrast between consistent detection of PCP chemicals in high Arctic snow and relatively low estimated LRET potential emphasizes the need for further research on their real-world atmospheric behavior under cold conditions.

2025

Addressing the advantages and limitations of using Aethalometer data to determine the optimal absorption Ångström exponents (AAEs) values for eBC source apportionment

Savadkoohi, Marjan; Gerras, Mohamed; Favez, Olivier; Petit, Jean-Eudes; Rovira, Jordi; Chen, Gang I.; Via, Marta; Platt, Stephen Matthew; Aurela, Minna; Chazeau, Benjamin; Brito, Joel F. De; Riffault, Véronique; Eleftheriadis, Kostas; Flentje, Harald; Gysel-Beer, Martin; Hueglin, Christoph; Rigler, Martin; Gregorič, Asta; Ivančič, Matic; Keernik, Hannes; Maasikmets, Marek; Liakakou, Eleni; Stavroulas, Iasonas; Luoma, Krista; Marchand, Nicolas; Mihalopoulos, Nikos; Petäjä, Tuukka; Prévôt, André S.H.; Daellenbach, Kaspar R.; Vodička, Petr; Timonen, Hilkka; Tobler, Anna; Vasilescu, Jeni; Dandocsi, Andrei; Mbengue, Saliou; Vratolis, Stergios; Zografou, Olga; Chauvigné, Aurélien; Hopke, Philip K.; Querol, Xavier; Alastuey, Andrés; Pandolfi, Marco

The apportionment of equivalent black carbon (eBC) to combustion sources from liquid fuels (mainly fossil; eBCLF) and solid fuels (mainly non-fossil; eBCSF) is commonly performed using data from Aethalometer instruments (AE approach). This study evaluates the feasibility of using AE data to determine the absorption Ångström exponents (AAEs) for liquid fuels (AAELF) and solid fuels (AAESF), which are fundamental parameters in the AE approach. AAEs were derived from Aethalometer data as the fit in a logarithmic space of the six absorption coefficients (470–950 nm) versus the corresponding wavelengths. The findings indicate that AAELF can be robustly determined as the 1st percentile (PC1) of AAE values from fits with R2 > 0.99. This R2-filtering was necessary to remove extremely low and noisy-driven AAE values commonly observed under clean atmospheric conditions (i.e., low absorption coefficients). Conversely, AAESF can be obtained from the 99th percentile (PC99) of unfiltered AAE values. To optimize the signal from solid fuel sources, winter data should be used to calculate PC99, whereas summer data should be employed for calculating PC1 to maximize the signal from liquid fuel sources. The derived PC1 (AAELF) and PC99 (AAESF) values ranged from 0.79 to 1.08, and 1.45 to 1.84, respectively. The AAESF values were further compared with those constrained using the signal at mass-to-charge 60 (m/z 60), a tracer for fresh biomass combustion, measured using aerosol chemical speciation monitor (ACSM) and aerosol mass spectrometry (AMS) instruments deployed at 16 sites. Overall, the AAESF values obtained from the two methods showed strong agreement, with a coefficient of determination (R2) of 0.78. However, uncertainties in both approaches may vary due to site-specific sources, and in certain environments, such as traffic-dominated sites, neither approach may be fully applicable.

2025

Measurement of three dimensional volcanic plume properties using multiple ground based infrared cameras

Wood, Kieran; Thomas, Helen E.; Watson, Matt; Calway, Andrew; Richardson, Tom; Stebel, Kerstin; Naismith, Ailsa; Berthoud, Lucy; Lucas, Josh

2019

MusicReco: Interactive Interface Modelling with User-Centered Design in a Music Recommendation System

Frantzvaag, Mats Ottem; Chatterjee, Ayan; Ghose, Debasish; Dash, Soumya P.

Recommendation technologies are widespread in streaming services, e-commerce, social media, news, and content management. Besides recommendation generation, its presentation is also important. Most research and development focus on the technical aspects of recommendation generation; therefore, a gap exists between recommendation generation and its effective presentation and user interaction. This study focuses on how personalized recommendations can be presented and interacted with in a music recommendation system using interactive visual interfaces. Interactive interface modeling with User-Centered Design (UCD) in a recommendation system is essential for creating a user-friendly, engaging, and personalized experience. By involving users in the recommendation process and considering their feedback, the system can deliver more relevant content, foster user trust, and improve overall user satisfaction and engagement. In this study, the visual interface design and development of a personalized music recommendation prototype (MusicReco) are presented using an iterative UCD approach, involving twenty end-users, one researcher, three academic professionals, and four experts. As the study is more inclined toward the recommendation presentation and visual modeling, we used a standard content-based filtering algorithm on the publicly available Spotify dataset for music recommendation generation. End-users helped to mature the MusicReco prototype to a basic working version through continuous feedback and design inputs on their needs, context, preferences, personalization, and effective visualization. Moreover, MusicReco captures the idea of mood-based tailored recommendations to encourage end-users. Overall, this study demonstrates how UCD can enhance the presentation and interaction of mood-based music recommendations, effectively engaging users with advancements in recommendation algorithms as a future focus.

2025

Publikasjon
År
Kategori