Fant 9764 publikasjoner. Viser side 58 av 391:
Luftkvalitet i Ny-Ålesund. Målinger av lokal luftkvalitet 2019 og 2020.
De målte konsentrasjonene var generelt lave for alle komponenter og under nasjonale grenseverdier for beskyttelse av menneskets helse og økosystemet. Vind fra nordlige sektorer ga de høyeste gjennomsnittskonsentrasjonene av nitrogenoksider og svoveldioksid, noe som peker på kraftstasjonen og havnen som mulige kilder. Vi ser også enkelte episoder med langtransport av svoveldioksid.
NILU
2021
2021
Aerosol particles are a complex component of the atmospheric system which influence climate directly by interacting with solar radiation, and indirectly by contributing to cloud formation. The variety of their sources, as well as the multiple transformations they may undergo during their transport (including wet and dry deposition), result in significant spatial and temporal variability of their properties. Documenting this variability is essential to provide a proper representation of aerosols and cloud condensation nuclei (CCN) in climate models. Using measurements conducted in 2016 or 2017 at 62 ground-based stations around the world, this study provides the most up-to-date picture of the spatial distribution of particle number concentration (Ntot) and number size distribution (PNSD, from 39 sites). A sensitivity study was first performed to assess the impact of data availability on Ntot's annual and seasonal statistics, as well as on the analysis of its diel cycle. Thresholds of 50 % and 60 % were set at the seasonal and annual scale, respectively, for the study of the corresponding statistics, and a slightly higher coverage (75 %) was required to document the diel cycle.
Although some observations are common to a majority of sites, the variety of environments characterizing these stations made it possible to highlight contrasting findings, which, among other factors, seem to be significantly related to the level of anthropogenic influence. The concentrations measured at polar sites are the lowest (∼ 102 cm−3) and show a clear seasonality, which is also visible in the shape of the PNSD, while diel cycles are in general less evident, due notably to the absence of a regular day–night cycle in some seasons. In contrast, the concentrations characteristic of urban environments are the highest (∼ 103–104 cm−3) and do not show pronounced seasonal variations, whereas diel cycles tend to be very regular over the year at these stations. The remaining sites, including mountain and non-urban continental and coastal stations, do not exhibit as obvious common behaviour as polar and urban sites and display, on average, intermediate Ntot (∼ 102–103 cm−3). Particle concentrations measured at mountain sites, however, are generally lower compared to nearby lowland sites, and tend to exhibit somewhat more pronounced seasonal variations as a likely result of the strong impact of the atmospheric boundary layer (ABL) influence in connection with the topography of the sites. ABL dynamics also likely contribute to the diel cycle of Ntot observed at these stations. Based on available PNSD measurements, CCN-sized particles (considered here as either >50 nm or >100 nm) can represent from a few percent to almost all of Ntot, corresponding to seasonal medians on the order of ∼ 10 to 1000 cm−3, with seasonal patterns and a hierarchy of the site types broadly similar to those observed for Ntot.
Overall, this work illustrates the importance of in situ measurements, in particular for the study of aerosol physical properties, and thus strongly supports the development of a broad global network of near surface observatories to increase and homogenize the spatial coverage of the measurements, and guarantee as well data availability and quality. The results of this study also provide a valuable, freely available and easy to use support for model comparison and validation, with the ultimate goal of contributing to improvement of the representation of aerosol–cloud interactions in models, and, therefore, of the evaluation of the impact of aerosol particles on climate.
2021
2021
As the leading climate mode of wintertime climate variability over Europe, the North Atlantic Oscillation (NAO) has been extensively studied over the last decades. Recently, studies highlighted the state of the Eurasian cryosphere as a possible predictor for the wintertime NAO. However, missing correlation between snow cover and wintertime NAO in climate model experiments and strong non-stationarity of this link in reanalysis data are questioning the causality of this relationship.
Here we use the large ensemble of Atmospheric Seasonal Forecasts of the 20th Century (ASF-20C) with the European Centre for Medium-Range Weather Forecasts model, focusing on the winter season. Besides the main 110-year ensemble of 51 members, we investigate a second, perturbed ensemble of 21 members where initial (November) land conditions over the Northern Hemisphere are swapped from neighboring years. The Eurasian snow–NAO linkage is examined in terms of a longitudinal snow depth dipole across Eurasia. Subsampling the perturbed forecast ensemble and contrasting members with high and low initial snow dipole conditions, we found that their composite difference indicates more negative NAO states in the following winter (DJF) after positive west-to-east snow depth gradients at the beginning of November. Surface and atmospheric forecast anomalies through the troposphere and stratosphere associated with the anomalous positive snow dipole consist of colder early winter surface temperatures over eastern Eurasia, an enhanced Ural ridge and increased vertical energy fluxes into the stratosphere, with a subsequent negative NAO-like signature in the troposphere. We thus confirm the existence of a causal connection between autumn snow patterns and subsequent winter circulation in the ASF-20C forecasting system.
2021
NILU – Norsk institutt for luftforskning og Ingenia AS har på oppdrag fra Statens vegvesen kartlagt effekten ventilasjonstårnene i Ekeberg- og Bjørvikatunnelen har med hensyn til å redusere luftforurensning fra dagsonen på Sørenga. Prosjektet besto av et omfangsrikt måleprogram i og rundt Operatunnelen i Bjørvika, en vurdering av ventilasjonstårnenes effekt basert på målingene og forslag til prinsipper for et nytt styringsregime.
Drift av ventilasjonstårnene ble funnet å ha en tydelig effekt på PM10- og NO2-konsentrasjonen i dagsonen og på bakkenivå utenfor dagsonen fra trinn 3 (av 4). Forslaget til nytt styringsregime fokuserer på ventilasjonstårndrift i piggdekksesongen og avhengighet av ytre forhold.
NILU
2021
Elevated stratopause events in the current and a future climate: A chemistry-climate model study
Elsevier
2021
On behalf of Aluminiumindustriens Miljøsekretariat (AMS), NILU – Norwegian Institute for Air Research has conducted a sampling campaign in the surroundings of the Hydro Sunndal aluminium smelter in order to update the knowledge on air quality around the smelter today. Samples were taken in summer 2019 and analysed for PM2.5, PM10, metals (Pb, Cd, Cr, Ni, As, Al, V, Ga, Sb, Bi), particle-bound PAHs, SO2, particle-bound and gaseous fluorides. As a consequence of reduced emissions compared to earlier measurements, the ambient concentrations of PM10, Cr, Pb, BaP (for PAHs), SO2 and fluorides were strongly reduced. All measured compounds had concentrations below limit values and recommended
guideline values.
NILU
2021
Spredningsberegninger av luftforurensning fra Årdal Metallverk
Rapporten presenterer oppdaterte spredningsberegninger for utslipp til luft fra Årdal Metallverk i Øvre Årdal. Utslippene er hentet fra utslippstillatelsen som en vurdering av «worst-case». Det er beregnet bakkekonsentrasjoner for SO2, støv og fluorider, samt metallkomponentene i utslippstillatelsen. Beregningene, som er basert på en konservativ metodikk, viser potensielt overskridelse av målsetningsverdier for nikkel og arsen i nærområdet til anlegget ved nivåene i utslippstillatelsen. Beregningene gir også fare for overskridelse for støv, men vurderingen er usikker fordi verken andelen PM2,5 og PM10 i utslippet eller bidraget fra øvrige kilder er kjent.
NILU
2021
Fate of Springtime Atmospheric Reactive Mercury: Concentrations and Deposition at Zeppelin, Svalbard
American Chemical Society (ACS)
2021
2021
2021
2021
2021
Calibration of CO, NO2, and O3 Using Airify: A Low-Cost Sensor Cluster for Air Quality Monitoring
MDPI
2021
Monitoring of greenhouse gases and aerosols at Svalbard and Birkenes in 2020. Annual report.
The report summarizes the activities and results of the greenhouse gas monitoring at the Zeppelin Observatory, situated on Svalbard in Arctic Norway, during the period 2001-2020, and the greenhouse gas monitoring and aerosol observations from Birkenes for 2009-2020.
NILU
2021
2021
2021
An Advanced In vitro Respiratory Model for Genotoxicity Testing at the Air-Liquid Interface
Elsevier
2021