Found 9764 publications. Showing page 344 of 391:
2022
2022
The atmosphere and cryosphere have recently garnered considerable attention due to their role in transporting microplastics to and within the Arctic, and between freshwater, marine, and terrestrial environments. While investigating either in isolation provides valuable insight on the fate of microplastics in the Arctic, monitoring both provides a more holistic view. Nonetheless, despite the recent scientific interest, fundamental knowledge on microplastic abundance and consistent monitoring efforts are lacking for these compartments. Here, we build upon the work of the Arctic Monitoring and Assessment Programme's Monitoring Guidelines for Litter and Microplastic to provide a roadmap for multicompartment monitoring of the atmosphere and cryosphere to support our understanding of the sources, pathways, and sinks of plastic pollution across the Arctic. Overall, we recommend the use of existing standard techniques for ice and atmospheric sampling and to build upon existing monitoring efforts in the Arctic to obtain a more comprehensive pan-Arctic view of microplastic pollution in these two compartments.
2022
2022
Aerosol distributions have a potentially large influence on climate-relevant cloud properties but can be difficult to observe over the Arctic given pervasive cloudiness, long polar nights, data paucity over remote regions, and periodic diamond dust events that satellites can misclassify as aerosol. We compared Arctic 2008–2015 mineral dust and combustion aerosol distributions from the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) satellite, the Modern-Era Retrospective analysis for Research and Applications, Version 2 (MERRA-2) reanalysis products, and the FLEXible PARTicle (FLEXPART) dispersion model. Based on coincident, seasonal Atmospheric Infrared Sounder (AIRS) Arctic satellite meteorological data, diamond dust may occur up to 60 % of the time in winter, but it hardly ever occurs in summer. In its absence, MERRA-2 and FLEXPART each predict the vertical and horizontal distribution of large-scale patterns in combustion aerosols with relatively high confidence (Kendall tau rank correlation > 0.6), although a sizable amount of variability is still unaccounted for. They do the same for dust, except in conditions conducive to diamond dust formation where CALIPSO is likely misclassifying diamond dust as mineral dust and near the surface...
2022
The miniaturized enzyme-modified comet assay for genotoxicity testing of nanomaterials
The in vitro comet assay is a widely applied method for investigating genotoxicity of chemicals including engineered nanomaterials (NMs). A big challenge in hazard assessment of NMs is possible interference between the NMs and reagents or read-out of the test assay, leading to a risk of biased results. Here, we describe both the standard alkaline version of the in vitro comet assay with 12 mini-gels per slide for detection of DNA strand breaks and the enzyme-modified version that allows detection of oxidized DNA bases by applying lesion-specific endonucleases (e.g., formamidopyrimidine DNA glycosylase or endonuclease III). We highlight critical points that need to be taken into consideration when assessing the genotoxicity of NMs, as well as basic methodological considerations, such as the importance of carrying out physicochemical characterization of the NMs and investigating uptake and cytotoxicity. Also, experimental design—including treatment conditions, cell number, cell culture, format and volume of medium on the plate—is crucial and can have an impact on the results, especially when testing NMs. Toxicity of NMs depends upon physicochemical properties that change depending on the environment. To facilitate testing of numerous NMs with distinct modifications, the higher throughput miniaturized version of the comet assay is essential.
Frontiers Media S.A.
2022
High-Resolution Emissions from Wood Burning in Norway—The Effect of Cabin Emissions
Emissions from wood burning for heating in secondary homes or cabins is an important part in the development of high-resolution emissions in specific areas. Norway is used as case study as 20% of the national wood consumption for heating occurs in cabins. Our study first shows a method to estimate emissions from cabins based on traffic data to derive cabin occupancy, which combined with heating need allows for the spatial and temporal distribution of emissions. The combination of residential (RWC) and cabin wood combustion (CWC) emissions shows large spatial and temporal differences, and a temporally “cabin population” can in areas be orders of magnitude larger than the registered population. While RWC emissions have been steadily reduced, CWC have kept relatively constant or even increased, which results in an increase in the cabin share to total heating emissions up to 25–35%. When comparing with regional emission inventories, our study shows that the gradient between rural and urban areas is not well-represented in regional inventories, which resembles a population-based distribution and does not allocate emissions in cabin municipalities. CWC emissions may become an increasing environmental concern as higher densification trends in mountain areas are observed.
MDPI
2022
2022
2022
Common Considerations for Genotoxicity Assessment of Nanomaterials
Genotoxicity testing is performed to determine potential hazard of a chemical or agent for direct or indirect DNA interaction. Testing may be a surrogate for assessment of heritable genetic risk or carcinogenic risk. Testing of nanomaterials (NM) for hazard identification is generally understood to require a departure from normal testing procedures found in international standards and guidelines. A critique of the genotoxicity literature in Elespuru et al., 2018, reinforced evidence of problems with genotoxicity assessment of nanomaterials (NM) noted by many previously. A follow-up to the critique of problems (what is wrong) is a series of methods papers in this journal designed to provide practical information on what is appropriate (right) in the performance of genotoxicity assays altered for NM assessment. In this “Common Considerations” paper, general considerations are addressed, including NM characterization, sample preparation, dosing choice, exposure assessment (uptake) and data analysis that are applicable to any NM genotoxicity assessment. Recommended methods for specific assays are presented in a series of additional papers in this special issue of the journal devoted to toxicology methods for assessment of nanomaterials: the In vitro Micronucleus Assay, TK Mutagenicity assays, and the In vivo Comet Assay. In this context, NM are considered generally as insoluble particles or test articles in the nanometer size range that present difficulties in assessment using techniques described in standards such as OECD guidelines.
Frontiers Media S.A.
2022
Svalbard is a remote and scarcely populated Arctic archipelago and is considered to be mostly influenced by long-range-transported air pollution. However, there are also local emission sources such as coal and diesel power plants, snowmobiles and ships, but their influence on the background concentrations of trace gases has not been thoroughly assessed. This study is based on data of tropospheric ozone (O3) and nitrogen oxides (NOx) collected in three main Svalbard settlements in spring 2017. In addition to these ground-based observations and radiosonde and O3 sonde soundings, ERA5 reanalysis and BrO satellite data have been applied in order to distinguish the impact of local and synoptic-scale conditions on the NOx and O3 chemistry. The measurement campaign was divided into several sub-periods based on the prevailing large-scale weather regimes. The local wind direction at the stations depended on the large-scale conditions but was modified due to complex topography. The NOx concentration showed weak correlation for the different stations and depended strongly on the wind direction and atmospheric stability. Conversely, the O3 concentration was highly correlated among the different measurement sites and was controlled by the long-range atmospheric transport to Svalbard. Lagrangian backward trajectories have been used to examine the origin and path of the air masses during the campaign.
2022
2022
2022
Monitoring of environmental contaminants in air and precipitation. Annual report 2021.
This report presents data from 2021 and time-trends for the Norwegian monitoring programme "Atmospheric contaminants". The results cover 200 organic compounds (regulated and non-regulated), 11 heavy metals, and a selection of organic chemicals of concern.
NILU
2022
Health Risk Assessment of Air Pollution and the Impact of the New WHO Guidelines
Air pollution is a major cause of premature death and disease and is the single largest environmental health risk in Europe. Heart disease and stroke are the most common reasons for premature deaths attributable to air pollution, followed by lung diseases and lung cancer.
The health risk assessment methodology assumptions have been recently adapted to follow the recommendations by the World Health Organisation (WHO), released in 2021. The new global air quality guidelines by WHO provide up-to-date health-based guideline levels for major health-damaging air pollutants and new recommendations for assessing the risk of exposure to air pollution.
This report estimates the health risk related to air pollution in 2020 based on the latest methodology. The estimates consider the number of premature deaths and years of life lost related to exposure to fine particulate matter, ozone and nitrogen dioxide, both for the 27 Member States of the European Union and for additional 14 European countries (Albania, Andorra, Bosnia and Herzegovina, Iceland, Kosovo, Liechtenstein, Monaco, Montenegro, North Macedonia, Norway, San Marino, Serbia, Switzerland, and Türkiye).
A sensitivity analysis to the changes in concentration-response functions and counterfactual concentrations is performed to understand the impact of such changes on the mortality outcome estimates. The sensitivity analysis included both old and new health risk methodology assumptions but also the recommendation from the ELAPSE study on the concentration response functions. The ELAPSE project includes some of the most recent studies on the health effects at low air pollution levels by examining associations between exposures to relatively low levels of air pollution across Europe, including levels below the current EU standards.
The results for 2020 show that the largest health risks are estimated for the countries with the largest populations. However, in relative terms, when considering e.g., years of life lost per 100 000 inhabitants, the largest relative risks are observed in central and eastern European countries for PM2.5, in central and southern European countries for NO2, and south and eastern European for O3. The lowest impact is found for the northern and north-western parts of Europe, where the concentrations are lowest. The number of premature deaths attributed to air pollution in 2020 compared to 2019, increased for PM2.5 and decreased for NO2 and O3. Apart from the changes in concentrations and demographics, the COVID-19 pandemics seems to also have an influence on these changes. For PM2.5, the reduction in concentrations were counteracted by the excess of deaths due to the pandemics. In the case of NO2, the reduction in concentrations was more pronounced as a result of the lockdown measures and the drastic reduction in traffic and its impact in reducing mortality was bigger than the increasing impact of excess of deaths due to COVID-19.
Changing assumptions on concentration-response functions and counterfactual concentrations have implications for estimating mortality health outcomes. The sensitivity analysis shows that it is not straightforward to assess which assumptions estimates the highest health impacts when both factors change. In this case, the final outcome will depend on the concentration at the grid-cell level. The latest assumptions are expected to reduce the health outcomes for PM2.5 and increase for NO2 and O3, when compared to the previous one. When aggregated to all countries, the health outcomes are reduced by over 40 % for PM2.5 and increased by 50 % and 30 % for NO2 and O3, respectively, in 2020. However, this change varies across countries depending on the concentration level the population in the individual countries is exposed to.
ETC/HE
2022
2022
The Arctic is warming two to three times faster than the global average, and the role of aerosols is not well constrained. Aerosol number concentrations can be very low in remote environments, rendering local cloud radiative properties highly sensitive to available aerosol. The composition and sources of the climate-relevant aerosols, affecting Arctic cloud formation and altering their microphysics, remain largely elusive due to a lack of harmonized concurrent multi-component, multi-site, and multi-season observations. Here, we present a dataset on the overall chemical composition and seasonal variability of the Arctic total particulate matter (with a size cut at 10 μm, PM10, or without any size cut) at eight observatories representing all Arctic sectors. Our holistic observational approach includes the Russian Arctic, a significant emission source area with less dedicated aerosol monitoring, and extends beyond the more traditionally studied summer period and black carbon/sulfate or fine-mode pollutants. The major airborne Arctic PM components in terms of dry mass are sea salt, secondary (non-sea-salt, nss) sulfate, and organic aerosol (OA), with minor contributions from elemental carbon (EC) and ammonium. We observe substantial spatiotemporal variability in component ratios, such as EC/OA, ammonium/nss-sulfate and OA/nss-sulfate, and fractional contributions to PM. When combined with component-specific back-trajectory analysis to identify marine or terrestrial origins, as well as the companion study by Moschos et al 2022 Nat. Geosci. focusing on OA, the composition analysis provides policy-guiding observational insights into sector-based differences in natural and anthropogenic Arctic aerosol sources. In this regard, we first reveal major source regions of inner-Arctic sea salt, biogenic sulfate, and natural organics, and highlight an underappreciated wintertime source of primary carbonaceous aerosols (EC and OA) in West Siberia, potentially associated with the oil and gas sector. The presented dataset can assist in reducing uncertainties in modelling pan-Arctic aerosol-climate interactions, as the major contributors to yearly aerosol mass can be constrained. These models can then be used to predict the future evolution of individual inner-Arctic atmospheric PM components in light of current and emerging pollution mitigation measures and improved region-specific emission inventories.
2022
Optical properties of surface aerosols at Dome C, Antarctica, in 2007–2013 and their potential source areas are presented. Scattering coefficients (σsp) were calculated from measured particle number size distributions with a Mie code and from filter samples using mass scattering efficiencies. Absorption coefficients (σap) were determined with a three-wavelength Particle Soot Absorption Photometer (PSAP) and corrected for scattering by using two different algorithms. The scattering coefficients were also compared with σsp measured with a nephelometer at the South Pole Station (SPO). The minimum σap was observed in the austral autumn and the maximum in the austral spring, similar to other Antarctic sites. The darkest aerosol, i.e., the lowest single-scattering albedo ωo≈0.91, was observed in September and October and the highest ωo≈0.99 in February and March. The uncertainty of the absorption Ångström exponent αap is high. The lowest αap monthly medians were observed in March and the highest in August–October. The equivalent black carbon (eBC) mass concentrations were compared with eBC measured at three other Antarctic sites: the SPO and two coastal sites, Neumayer and Syowa. The maximum monthly median eBC concentrations are almost the same ( ng m−3) at all these sites in October–November. This suggests that there is no significant difference in eBC concentrations between the coastal and plateau sites. The seasonal cycle of the eBC mass fraction exhibits a minimum f(eBC) ≈0.1 % in February–March and a maximum ∼4 %–5 % in August–October. Source areas were calculated using 50 d FLEXPART footprints. The highest eBC concentrations and the lowest ωo were associated with air masses coming from South America, Australia and Africa. Vertical simulations that take BC particle removal processes into account show that there would be essentially no BC particles arriving at Dome C from north of latitude 10∘ S at altitudes
2022
2022
2022
Revidert tiltaksutredning for lokal luftkvalitet i Bergen
Tiltaksutredningen for lokal luftkvalitet i Bergen med handlings- og beredskapsplan skal bidra til at forurensningsnivået holder seg innenfor kravene i forurensningsforskriften. Tiltaksutredningen omfatter en kartlegging av luftkvaliteten i Bergen kommune ved trafikkberegninger og utslipps- og spredningsberegninger for PM10, PM2,5 og NO 2 for Dagens situasjon 2019 og Referansesituasjonen 2030 med eksisterende og eventuelle nye tiltak. Utredningen vurderer effekten som tiltakene har for å overholde krav, men ser også på muligheten for ytterligere reduksjon i henhold til anbefalingene til helsemyndighetene. Basert på resultatene fra beregningene og i samarbeid med oppdragsgiver og referansegruppen, er det foreslått en revidert handlings- og beredskapsplan som skal behandles politisk.
NILU
2022