Found 9985 publications. Showing page 70 of 400:
2021
Seasonal Variation of Wet Deposition of Black Carbon at Ny-Ålesund, Svalbard
Black carbon (BC) aerosol deposited in and onto Arctic snow increases the snow's absorption of solar radiation and accelerates snowmelt. Concentrations of BC in the Arctic atmosphere and snow are controlled by wet deposition; however, details of this process are poorly understood owing to the scarcity of time-resolved measurements of BC in hydrometeors. We measured mass concentrations of BC in hydrometeors (CMBC) and in air (MBC) with 16% and 15% accuracies, respectively, at Ny-Ålesund, Svalbard during 2012–2019. Median monthly MBC and CMBC values showed similar seasonal variations, being high in winter-spring and low in summer. Median monthly BC wet deposition mass flux (FMBC) was highest in winter and lowest in summer, associated with seasonal patterns of CMBC and precipitation. Seasonally averaged BC size distributions in hydrometeors were similar except for summer. Measurements of MBC and CMBC in spring 2017 showed a size-independent removal efficiency, indicating that BC-containing particles were efficiently activated into cloud droplets. These observations at Ny-Ålesund were compared with observations at Barrow, Alaska, during 2013–2017. The near-surface MBC at Ny-Ålesund and Barrow had similar seasonal patterns; however, the two sites differed in CMBC and FMBC. In summer, CMBC was low at Ny-Ålesund but moderate at Barrow, likely reflecting differences in MBC in the lower troposphere. Seasonally averaged BC size distributions in hydrometeors were similar at both sites, suggesting that average BC size distributions are similar in the Arctic lower troposphere. The efficiency of BC removal tends to be size-independent during transport, leading to the observed similarity.
2021
2021
Eastward-propagating planetary waves prior to the January 2009 sudden stratospheric warming
Eastward-propagating planetary waves (EPWs) were investigated prior to the boreal January 2009 major sudden stratospheric warming (SSW) event simulated by the National Center for Atmospheric Research's Whole Atmosphere Community Climate Model with specified dynamics. About 22 days before SSW onset, a background flow with jet maxima around the upper polar stratosphere and subtropical mesosphere developed due to the net forcing by gravity and planetary waves. The mesospheric wind structure was largely unstable and supported a wave geometry conducive to overreflection. With a zonal phase speed of ∼10 m s−1, EPWs appeared near their turning and critical layers as wavenumber-2 perturbations in the stratosphere and mesosphere. Accompanied by upward EPW activity from the lower stratosphere, EPW growth exhibited characteristics of wave instability and overreflection.
2021
Using the Super Dual Auroral Radar Network observations (clustered around 60°N) and NCAR CESM2.0 extended Whole Atmosphere Community Climate Model nudged with reanalyzes, we examine the climatology of semidiurnal tides in meridional wind associated with the migrating component (SW2) and non‐migrating components of wavenumbers 1 (SW1) and 3 (SW3). We then illustrate their composite response to major sudden stratospheric warmings (SSWs). Peaking in late summer and winter, the climatological SW2 amplitude exceeds SW1 and SW3 except around late Fall and Spring. The winter climatological peak is absent in the model perhaps due to the zonal wind bias at the observed altitudes. The observed SW2 amplitude declines after SSW onset before enhancing ∼10 days later, along with SW1 and SW3. Within the observed region, the simulated SW2 only amplifies after SSW onset, with minimal SW1 and SW3 responses. The model reveals a stronger SW2 response above the observed location, with diminished amplitude before and enhancement after SSW globally. This enhancement appears related to increased equatorial ozone heating and background wind symmetry. The strongest SW1 and SW3 growth occurs in the Southern Hemisphere before SSW. SW2 and quasi‐stationary planetary wave activities are temporally collocated during SSW suggesting that their interactions excite SW1 and SW3. After SSW, the model also reveals (1) semidiurnal‐tide‐like perturbations generated possibly by the interactions between SW2 and westward‐traveling disturbances and (2) the enhancement of migrating semidiurnal lunar tide in the Northern Hemisphere that exceeds non‐migrating tidal and semidiurnal‐tide‐like responses. The simulated eastward‐propagating semidiurnal tides are briefly examined.
2021
Links to Copernicus data and services. Status and recommendations.
This report presents available Copernicus data from both its satellite and service component. It contains a comprehensive overview of the status of use of Copernicus data and products in the work of the European Environment Agency (EEA) and provides recommendations to make better use of Copernicus information focusing on the activities of the European Topic Centre for Air pollution, Transport, Noise, and Industry pollution (ETC/ATNI). Specific recommended activities to make better use of Copernicus data involve mapping and emission activities at ETC/ATNI, trend analysis, noise, and air quality assessments as well as the development of on-line air quality services and the implementation of urban sustainability studies.
ETC/ATNI
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
Fluorinated polymers in a low carbon, circular and toxic-free economy. Technical report.
Fluorinated polymers are used in a variety of applications providing benefits to the society, but at the same time also causing risks of irreversible pollution and impacts on the environment and human health in different stages of the lifecycle. The main aim of the study was to provide information on impacts of fluorinated polymers along their lifecycles in a low carbon, circular and toxic-free economy, which could be relevant to consider in future assessments. An important part of the work was also to discuss options for risk governance and to identify knowledge gaps. The work was based on a literature survey of recently published reports and selected peer-reviewed articles on the topic.
The report presents the results of the work carried out by the ETC/WMGE and ETC/CME.
ETC/WMGE
2021
Residential wood combustion (RWC) is a major source of air pollutants in the Nordic and many other countries. The emissions of the pollutants have been estimated with inventories on several scopes, e.g. local and national. An important aspect of the inventories is the spatial distribution of the emissions, as it has an effect on health impact assessments. In this study, we present a novel residential wood combustion emission inventory for the Nordic countries based on national inventories and new gridding of the emissions. We compare the emissions of the Nordic inventory, and especially their spatial distribution, to local assessments and European level TNO-newRWC-inventory to assess the spatial proxies used. Common proxies used in the national inventories in the Nordic countries were building data on locations and primary heating methods and questionnaire-based wood use estimates for appliances or primary heating methods. Chimney sweeper register data was identified as good proxy data, but such data may not be available in an applicable format. Comparisons of national inventories to local assessments showed the possibility to achieve similar spatial distributions through nation-wide methods as local ones. However, this won't guarantee that the emissions are similar. Comparison to the TNO-newRWC-inventory revealed the importance of how differences between urban and rural residential wood combustion are handled. The comparison also highlighted the importance of local characteristics of residential wood combustion in the spatial distribution of emissions.
2021
This report presents VOC (volatile organic compound) measurements carried out during 2019 at EMEP monitoring sites. In total, 19 sites reported VOC-data from EMEP VOC sites this year. Some of the data-sets are considered preliminary and are not included in the report.
The monitoring of VOC has become more diverse with time in terms of instrumentation. Starting in the early 1990s with standardized methods based on manual sampling in steel canisters and adsorption tubes with subsequent analyses at the lab, the methods now consist of a variety of instruments and measurement principles, including automated continuous monitors and manual flask samples.
Within the EU infrastructure project ACTRIS, data quality issues related to measurements of VOC are an important topic. Many of the institutions providing VOC-data to EMEP are participating in the ACTRIS infrastructure project, either as formal partners or on a voluntary basis. Participation in ACTRIS means an extensive effort with data-checking including detailed discussions between the ACTRIS community and individual participants. There is no doubt that this extensive effort has benefited the EMEP-program substantially and has led to improved data quality in general.
Comparison between median levels in 2019 and the medians of the previous 10-years period, revealed similar geographical patterns as in the previous years. Changes in instrumentation, procedures and station network with time make it difficult though to provide a rigorous and pan-European assessment of long-term trends of the observed VOCs. In this report, we have estimated the trends in NMHC over the 2000-2019 period at five sites by three independent statistical methods. All three methods gave comparable estimates of the trends, although the Mann-Kendall method based on annual data (compared to daily data for the other two methods) found fewer significant trends.
These estimates indicate marked differences in the long-term trends for the individual species. Small or non-significant trends were found for ethane during 2000-2019. Propane also showed fairly small reductions. On the other hand, components linked to road traffic (ethene, ethyne and benzene) showed the strongest drop in mean concentrations, up to 60-80% at some stations.
NILU
2021
Transboundary particulate matter, photo-oxidants, acidifying and eutrophying components
Norwegian Meteorological Institute
2021
Assessing the impacts of citizen-led policies on emissions, air quality and health
Air pollution is a global challenge, and especially urban areas are particularly affected by acute episodes. Traditional approaches used to mitigate air pollution primarily consider the technical aspects of the problem but not the role of citizen behaviour and day-to-day practices. ClairCity, a Horizon 2020 funded project, created an impact assessment framework considering the role of citizen behaviour to create future scenarios, aiming to improve urban environments and the wellbeing and health of its inhabitants. This framework was applied to six pilot cases: Bristol, Amsterdam, Ljubljana, Sosnowiec, Aveiro Region and Liguria Region, considering three-time horizons: 2025, 2035 and 2050. The scenarios approach includes the Business As Usual (BAU) scenario and a Final Unified Policy Scenarios (FUPS) established by citizens, decision-makers, local planners and stakeholders based on data collected through a citizen and stakeholder co-creation process. Therefore, this paper aims to present the ClairCity outcomes, analysing the quantified impacts of selected measures in terms of emissions, air quality, population exposure, and health. Each case study has established a particular set of measures with different levels of ambition, therefore different levels of success were achieved towards the control and mitigation of their specific air pollution problems. The transport sector was the most addressed by the measures showing substantial improvements for NO2, already with the BAU scenarios, and overall, even better results when applying the citizen-led FUPS scenarios. In some cases, due to a lack of ambition for the residential and commercial sector, the results were not sufficient to fulfil the WHO guidelines. Overall, it was found in all cities that the co-created scenarios would lead to environmental improvements in terms of air quality and citizens’ health compared to the baseline year of 2015. However, in some cases, the health impacts were lower than air quality due to the implementation of the measures not affecting the most densely populated areas. Benefits from the FUPS comparing to the BAU scenario were found to be highest in Amsterdam and Bristol, with further NO2 and PM10 emission reductions around 10%–16% by 2025 and 19%–28% by 2050, compared to BAU.
2021
2021
Quality assurance and quality control procedure for national and Union GHG projections 2021
The quality assurance and quality control (QA/QC) procedure is an element of the QA/QC programme of the Union system for policies and measures and projections to be established in 2021 according to Article 39 of the Regulation on the Governance of the Energy Union and Climate Action (EU) 2018/1999. The European Environment Agency (EEA) is responsible for the annual implementation of the QA/QC procedures and is assisted by the European Topic Centre on Climate Change Mitigation and Energy (ETC/CME). The QA/QC procedure document describes QA/QC checks carried out at EU level on the national reported projections from Member States and on the compiled Union GHG projections. QA/QC procedures are performed at several different stages during the preparation of the national and Union GHG projections in order to aim to ensure the timeliness, transparency, accuracy, consistency, comparability and completeness of the reported information. The results of the 2021 QA/QC procedure are presented in the related paper ETC/CME Eionet Report 8/2021.
ETC/CME
2021
Effects of rocket launches in Ny-Ålesund, 2018 - 2019. Observations of snow and air samples.
The report summarizes the results from additional snow sampling and regular monitoring activities in connection to the rocket launch in Ny-Ålesund 7 Dec 2018, 26 Nov 2019 and 10 Dec 2019 to document possible impacts on environment and on the monitoring activities in Ny-Ålesund. An enhanced deposition of aluminium (Al) and iron (Fe) on the local environment due to the rocket launch is observed.
NILU
2021
2021
2021