Fant 9831 publikasjoner. Viser side 375 av 394:
2024
2024
An extraordinary charge transfer kinetics and chemical stability make a boron-doped diamond (BDD) a promising material for electrochemical applications including wastewater treatment. Yet, with flat geometrical surfaces its scaling options are limited. In this study, the reticulated Vitreous Carbon (RVC) served as a substrate for boron-doped diamondized nanocarbons (BDNC) film growth resulting with complex heterogeneity carbon structures with different morphologies defined by using electron microscopy, microtomography, activation energy studies, and Raman spectroscopy.
The proposed modification significantly boosted the electrochemical Fe(CN)63−/4− redox activity. The voltammetry and impedimetric studies revealed its origin as a significantly higher share of electrochemically active sites at the BDNC@RVC electrode (increased by 114 %) combined with enhanced heterogeneous rate constant (2× increase up to 8.24·10−4 cm s−1). Finally, to establish its applicability for water treatment, the BDNC@RVC was studied as the anode in electrochemical paracetamol decomposition. Boron-enriched nanoarchitecture formed at the RVC electrode surface substantially reduced the oxidation energy barrier manifested as a decrease in activation overpotential by 212 mV, which gave a consequence in a 78 % removal rate (in 4 h, at 0.7 mA cm−2), 12 % higher than bare RVC and yielding lower amounts of APAP decomposition intermediates.
2024
Air quality in Sandefjord, Norway. November 2021 – August 2023.
This report examines the air quality patterns in terms of particulate matter with a diameter less than 2.5 μm (PM2.5) in Sandefjord, Norway. PM2.5 was monitored through five low-cost sensors in hourly resolution from November 2021 to August 2023. The sensors’ reliability is high, with consistent PM2.5 measurements and similar variation over time. Occasional extreme PM2.5 was attributed to local contributions with higher values observed during cold months, or specific long-range transport events. Overall, Sandefjord maintained good air quality for most of the measurement period with daily PM2.5 levels below the air quality criteria. Residential heating activities (wood burning) is the most significant local source, being more pronounced during winter.
NILU
2024
Dechloranes and chlorinated paraffins in sediments and biota of two subarctic lakes
Our understanding of the environmental behavior, bioaccumulation and concentrations of chlorinated paraffins (CPs) and Dechloranes (Dec) in the Arctic environment is still limited, particularly in freshwater ecosystems. In this descriptive study, short chain (SCCPs) and medium chain (MCCPs) CPs, Dechlorane Plus (DP) and analogues, and polychlorinated biphenyls (PCBs) were measured in sediments, benthic organisms, three-spined stickleback (Gasterosteus aculeatus), Arctic char (Salvelinus alpinus) and brown trout (Salmo trutta) in two Sub-Arctic lakes in Northern Norway. Takvannet (TA) is a remote lake, with no known local sources for organic contaminants, while Storvannet (ST) is situated in a populated area. SCCPs and MCCPs were detected in all sediment samples from ST with concentration of 42.26–115.29 ng/g dw and 66.18–136.69 ng/g dw for SCCPs and MCCPs, respectively. Only SCCPs were detected in TA sediments (0.4–5.28 ng/g dw). In biota samples, sticklebacks and benthic organisms showed the highest concentrations of CPs, while concentrations were low or below detection limits in both char and trout. The congener group patterns observed in both lakes showed SCCP profiles dominated by higher chlorinated congener groups while the MCCPs showed consistency in their profiles, with C14 being the most prevalent carbon chain length. Anti- and syn-DP isomers were detected in all sediment, benthic and stickleback samples with higher concentrations in ST than in TA. However, they were only present in a few char and trout samples from ST. Dec 601 and 604 were below detection limits in all samples in both lakes. Dec 603 was detected only in ST sediments, sticklebacks and 2 trout samples, while Dec 602 was the only DP analogue found in all samples from both lakes. While there were clear differences in sediment concentrations of DP and Dec 602 between ST and TA, differences between lakes decreased with increasing δ15N. This pattern was similar to the PCB behavior, suggesting the lake characteristics in ST are playing an important role in the lack of biomagnification of pollutants in this lake. Our results suggest that ST receives pollutants from local sources in addition to atmospheric transport.
Frontiers Media S.A.
2024
Pioneering an effect-based early warning system for hazardous chemicals in the environment
Existing regulatory frameworks often prove inadequate in promptly identifying contaminants of emerging concern (CECs) and determining their impacts on biological systems at an early stage. The establishment of Early Warning Systems (EWSs) for CECs is becoming increasingly relevant for policy-making, aiming to proactively detect chemical hazards and implement effective mitigation measures. Effect-based methodologies, including bioassays and effect-directed analysis (EDA), offer valuable input to EWSs by pinpointing the relevant toxicity drivers and prioritizing the associated risks. This review evaluates the analytical techniques currently available to assess biological effects, and provides a structured plan for their systematic integration into an EWS for hazardous chemicals in the environment. Key scientific advancements in effect-based approaches and EDA are discussed, underscoring their potential for early detection and management of chemical hazards. Additionally, critical challenges such as data integration and regulatory alignment are addressed, emphasizing the need for continuous improvement of the EWS and the incorporation of analytical advancements to safeguard environmental and public health from emerging chemical threats.
2024
The Sentinel-5 Precursor (S5P) satellite operated by the European Space Agency has carried the TROPOspheric Monitoring Instrument (TROPOMI) on a Sun-synchronous low-Earth orbit since 13 October 2017. The S5P mission has acquired more than 5 years of TROPOMI nadir ozone profile data retrieved from the level 0 to 1B processor version 2.0 and the level 1B to 2 optimal-estimation-based processor version 2.4.0. The latter is described in detail in this work, followed by the geophysical validation of the resulting ozone profiles for the period May 2018 to April 2023. Comparison of TROPOMI ozone profile data to co-located ozonesonde and lidar measurements used as references concludes to a median agreement better than 5 % to 10 % in the troposphere. The bias goes up to −15 % in the upper stratosphere (35–45 km) where it can exhibit vertical oscillations. The comparisons show a dispersion of about 30 % in the troposphere and 10 % to 20 % in the upper troposphere to lower stratosphere and in the middle stratosphere, which is close to mission requirements. Chi-square tests of the observed differences confirm on average the validity of the ex ante (prognostic) satellite and ground-based data uncertainty estimates in the middle stratosphere above about 20 km. Around the tropopause and below, the mean chi-square value increases up to about four, meaning that the ex ante TROPOMI uncertainty is underestimated. The information content of the ozone profile retrieval is characterised by about five to six vertical subcolumns of independent information and a vertical sensitivity (i.e. the fraction of the information that originates from the measurement) nearly equal to unity at altitudes from about 20 to 50 km, decreasing rapidly at altitudes above and below. The barycentre of the retrieved information is usually close to the nominal retrieval altitude in the 20–50 km altitude range, with positive and negative offsets of up to 10 km below and above this range, respectively. The effective vertical resolution of the profile retrieval usually ranges within 10–15 km, with a minimum close to 7 km in the middle stratosphere. Increased sensitivities and higher effective vertical resolutions are observed at higher solar zenith angles (above about 60°), as can be expected, and correlate with higher retrieved ozone concentrations. The vertical sensitivity of the TROPOMI tropospheric ozone retrieval is found to depend on the solar zenith angle, which translates into a seasonal and meridian dependence of the bias with respect to reference measurements. A similar although smaller effect can be seen for the viewing zenith angle. Additionally, the bias is negatively correlated with the surface albedo for the lowest three ozone subcolumns (0–18 km), despite the albedo's apparently slightly positive correlation with the retrieval degrees of freedom in the signal. For the 5 years of TROPOMI ozone profile data that are available now, an overall positive drift is detected for the same three subcolumns, while a negative drift is observed above (24–32 km), resulting in a negligible vertically integrated drift.
2024
Data Report 2022. Particulate matter, carbonaceous and inorganic compounds
This report presents an overview of annual statistical summaries and methods for sampling and analysis of particulate matter, carbonaceous and inorganic compounds measured under the EMEP monitoring programme in 2022.
NILU
2024
Høysesong for svevestøv: Bør vi sove med lukket vindu?
Norges forskningsråd
2024
2024
Recent methane surges reveal heightened emissions from tropical inundated areas
Record breaking atmospheric methane growth rates were observed in 2020
and 2021 (15.2±0.5 and 17.8±0.5 parts per billion per year), the highest since the
early 1980s. Here we use an ensemble of atmospheric inversions informed by
surface or satellite methane observations to infer emission changes during
these two years relative to 2019. Results show global methane emissions
increased by 20.3±9.9 and 24.8±3.1 teragrams per year in 2020 and 2021,
dominated by heightened emissions from tropical and boreal inundated areas,
aligning with rising groundwater storage and regional warming. Current
process-based wetland models fail to capture the tropical emission surges
revealed by atmospheric inversions, likely due to inaccurate representation of
wetland extents and associated methane emissions. Our findings underscore
the critical role of tropical inundated areas in the recent methane emission
surges and highlight the need to integrate multiple data streams and modeling
tools for better constraining tropical wetland emissions.
Springer Nature
2024
2024
Måling av luftkvalitet i Forsvarets forlegning i Bamako. Målinger for Det norske forsvaret 2022.
NILU
2024
The Greenhouse Gas Budget of Terrestrial Ecosystems in East Asia Since 2000
East Asia (China, Japan, Koreas, and Mongolia) has been the world's economic engine over at least the past two decades, exhibiting a rapid increase in fossil fuel emissions of greenhouse gases (GHGs) and has expressed the recent ambition to achieve climate neutrality by mid-century. However, the GHG balance of its terrestrial ecosystems remains poorly constrained. Here, we present a synthesis of the three most important long-lived greenhouse gases (CO2, CH4, and N2O) budgets over East Asia during the decades of 2000s and 2010s, following a dual constraint approach. We estimate that terrestrial ecosystems in East Asia is close to neutrality of GHGs, with a magnitude of between −46.3 ± 505.9 Tg CO2eq yr−1 (the top-down approach) and −36.1 ± 207.1 Tg CO2eq yr−1 (the bottom-up approach) during 2000–2019. This net GHG sink includes a large land CO2 sink (−1229.3 ± 430.9 Tg CO2 yr−1 based on the top-down approach and −1353.8 ± 158.5 Tg CO2 yr−1 based on the bottom-up approach) being offset by biogenic CH4 and N2O emissions, predominantly coming from the agricultural sectors. Emerging data sources and modeling capacities have helped achieve agreement between the top-down and bottom-up approaches, but sizable uncertainties remain in several flux terms. For example, the reported CO2 flux from land use and land cover change varies from a net source of more than 300 Tg CO2 yr−1 to a net sink of ∼−700 Tg CO2 yr−1. Although terrestrial ecosystems over East Asia is close to GHG neutral currently, curbing agricultural GHG emissions and additional afforestation and forest managements have the potential to transform the terrestrial ecosystems into a net GHG sink, which would help in realizing East Asian countries' ambitions to achieve climate neutrality.
American Geophysical Union (AGU)
2024
2024
Environmental dose-response functions of silk and paper exposed in museums.
This paper reports 1 year of data of the environments and changes in the molecular weight of silk and the degree of polymerization of sensitive paper measured externally and indoors in 10 European museums, and the dose-response functions that were obtained by statistical analysis of this data. The measurements were performed in the EU FP5 project Master (EVK-CT-2002-00093). The work provides documentation of deterioration of silk by NO2 and O3, and alternatively in combination with UV radiation. The indoor deterioration of the silk was only observed in one location with high UV radiation. The indoor deterioration of sensitive paper correlated with the UV radiation, the concentrations of NO2 and O3, and in addition with an SO2 concentration of 4 µgm−3 and a formic acid concentration of 50 µgm−3 in two different locations. If the observed dose-response effects are linear to lower doses and longer exposure times, then the lifetime to intolerable deterioration of the paper and silk would be 6–7 times longer overall in the enclosures than in the galleries.
2024
2024
Environmental pollutants in the terrestrial and urban environment 2023
Samples from the urban terrestrial environment in the Oslo area were analysed for metals and a large number of organic environmental pollutants. The selected samples that were analysed were soil, earthworm, fieldfare egg, brown rat liver, roe deer liver, vegetation, honeybee, and Spanish slug. Biomagnification potential was estimated based on detected data for relevant predator-prey pairs.
NILU
2024