Fant 10002 publikasjoner. Viser side 65 av 401:
2021
This paper presents a modelling study on the fate of CHBr3 and its product gases in the troposphere within the context of tropical deep convection. A cloud-scale case study was conducted along the west coast of Borneo, where several deep convective systems were triggered on the afternoon and early evening of 19 November 2011. These systems were sampled by the Falcon aircraft during the field campaign of the SHIVA project and analysed using a simulation with the cloud-resolving meteorological model C-CATT-BRAMS at 2×2 km resolution that represents the emissions, transport by large-scale flow, convection, photochemistry, and washout of CHBr3 and its product gases (PGs). We find that simulated CHBr3 mixing ratios and the observed values in the boundary layer and the outflow of the convective systems agree. However, the model underestimates the background CHBr3 mixing ratios in the upper troposphere, which suggests a missing source at the regional scale. An analysis of the simulated chemical speciation of bromine within and around each simulated convective system during the mature convective stage reveals that >85 % of the bromine derived from CHBr3 and its PGs is transported vertically to the point of convective detrainment in the form of CHBr3 and that the remaining small fraction is in the form of organic PGs, principally insoluble brominated carbonyls produced from the photo-oxidation of CHBr3. The model simulates that within the boundary layer and free troposphere, the inorganic PGs are only present in soluble forms, i.e. HBr, HOBr, and BrONO2, and, consequently, within the convective clouds, the inorganic PGs are almost entirely removed by wet scavenging. We find that HBr is the most abundant PG in background lower-tropospheric air and that this prevalence of HBr is a result of the relatively low background tropospheric ozone levels at the regional scale. Contrary to a previous study in a different environment, for the conditions in the simulation, the insoluble Br2 species is hardly formed within the convective systems and therefore plays no significant role in the vertical transport of bromine. This likely results from the relatively small quantities of simulated inorganic bromine involved, the presence of HBr in large excess compared to HOBr and BrO, and the relatively efficient removal of soluble compounds within the convective column.
2021
Modeling study of the impact of SO2 volcanic passive emissions on the tropospheric sulfur budget
Well constrained volcanic emissions inventories in chemistry transport models are necessary to study the impacts induced by these sources on the tropospheric sulfur composition and on sulfur species concentrations and depositions at the surface. In this paper, the changes induced by the update of the volcanic sulfur emissions inventory are studied using the global chemistry transport model MOCAGE (MOdèle de Chimie Atmosphérique à Grande Échelle). Unlike the previous inventory (Andres and Kasgnoc, 1998), the updated one (Carn et al., 2016, 2017) uses more accurate information and includes contributions from both passive degassing and eruptive emissions. Eruptions are provided as daily total amounts of sulfur dioxide (SO2) emitted by volcanoes in the Carn et al. (2016, 2017) inventories, and degassing emissions are provided as annual averages with the related mean annual uncertainties of those emissions by volcano. Information on plume altitudes is also available and has been used in the model. We chose to analyze the year 2013, for which only a negligible amount of eruptive volcanic SO2 emissions is reported, allowing us to focus the study on the impact of passive degassing emissions on the tropospheric sulfur budget. An evaluation against the Ozone Monitoring Instrument (OMI) SO2 total column and MODIS (Moderate-Resolution Imaging Spectroradiometer) aerosol optical depth (AOD) observations shows the improvements of the model results with the updated inventory. Because the global volcanic SO2 flux changes from 13 Tg yr−1 in Andres and Kasgnoc (1998) to 23.6 Tg yr−1 in Carn et al. (2016, 2017), significant differences appear in the global sulfur budget, mainly in the free troposphere and in the tropics. Even though volcanic SO2 emissions represent 15 % of the total annual sulfur emissions, the volcanic contribution to the tropospheric sulfate aerosol burden is 25 %, which is due to the higher altitude of emissions from volcanoes. Moreover, a sensitivity study on passive degassing emissions, using the annual uncertainties of emissions per volcano, also confirmed the nonlinear link between tropospheric sulfur species content with respect to volcanic SO2 emissions. This study highlights the need for accurate estimates of volcanic sources in chemistry transport models in order to properly simulate tropospheric sulfur species.
2021
The increased availability of commercially-available low-cost air quality sensors combined with increased interest in their use by citizen scientists, community groups, and professionals is resulting in rapid adoption, despite data quality concerns. We have characterized three out-the-box PM sensor systems under different environmental conditions, using field colocation against reference equipment. The sensor systems integrate Plantower 5003, Sensirion SPS30 and Alphasense OCP-N3 PM sensors. The first two use photometry as a measuring technique, while the third one is an optical particle counter. For the performance evaluation, we co-located 3 units of each manufacturer and compared the results against optical (FIDAS) and gravimetric (KFG) methods for a period of 7 weeks (28 August to 19 October 2020). During the period from 2nd and 5th October, unusually high PM concentrations were observed due to a long-range transport episode. The results show that the highest correlations between the sensor systems and the optical reference are observed for PM1, with coefficients of determination above 0.9, followed by PM2.5. All the sensor units struggle to correctly measure PM10, and the coefficients of determination vary between 0.45 and 0.64. This behavior is also corroborated when using the gravimetric method, where correlations are significantly higher for PM2.5 than for PM10, especially for the sensor systems based on photometry. During the long range transport event the performance of the photometric sensors was heavily affected, and PM10 was largely underestimated. The sensor systems evaluated in this study had good agreement with the reference instrumentation for PM1 and PM2.5; however, they struggled to correctly measure PM10. The sensors also showed a decrease in accuracy when the ambient size distribution was different from the one for which the manufacturer had calibrated the sensor, and during weather conditions with high relative humidity. When interpreting and communicating air quality data measured using low-cost sensor systems, it is important to consider such limitations in order not to risk misinterpretation of the resulting data.
2021
Global predictions of primary soil salinization under changing climate in the 21st century
Soil salinization has become one of the major environmental and socioeconomic issues globally and this is expected to be exacerbated further with projected climatic change. Determining how climate change influences the dynamics of naturally-occurring soil salinization has scarcely been addressed due to highly complex processes influencing salinization. This paper sets out to address this long-standing challenge by developing data-driven models capable of predicting primary (naturally-occurring) soil salinity and its variations in the world’s drylands up to the year 2100 under changing climate. Analysis of the future predictions made here identifies the dryland areas of South America, southern and western Australia, Mexico, southwest United States, and South Africa as the salinization hotspots. Conversely, we project a decrease in the soil salinity of the drylands in the northwest United States, the Horn of Africa, Eastern Europe, Turkmenistan, and west Kazakhstan in response to climate change over the same period.
2021
Vurdering av CLEO for norske reindriftsutøvere
Denne rapporten er en evaluering av Local Environmental Observer (LEO) Network ved bruk av erfaringene fra pilottestene utført i perioden 2016-2020 av arktiske akademikere, urfolksinstitusjoner og samisk samfunn i Norge. Rapporten prøver å finne svar på hvordan man kan tilrettelegge for innrapportering av observasjoner på lokale miljøendringer blant norske reindriftsutøvere samt opprettholde en utstrakt bruk. Dette for å skape engasjement, bevisstgjøring, forsterke lokale stemmer og identifisere svar på viktige miljøutfordringer og mulige handlinger, og søke konstruktive og respektfulle måter å dele informasjon og samarbeid mellom ulike kunnskapssystemer.
Rapporten konkluderer med at for å gjøre det mulig for norske reindriftsutøvere å rapportere inn observasjoner av klimaendringer i miljøet, og legge til rette for en utstrakt og kontinuerlig bruk, bør det bygges en egen Sápmi løsning.
NILU
2021
2021
2021
Status report of air quality in Europe for year 2019, using validated data
This report presents summarized information on the status of air quality in Europe in 2019, based on validated air quality monitoring data officially reported by the member and cooperating countries of the EEA. It aims at informing on the status of ambient air quality in Europe in 2019 and on the progress towards meeting the European air quality standards for the protection of health, as well as the WHO air quality guidelines. The report also compares the air quality status in 2019 with the previous three years. The pollutants covered in this report are particulate matter (PM10 and PM2.5), O3, NO2, benzo(a)pyrene (BaP), SO2, CO, benzene and toxic metals (As, Cd, Ni, Pb). Measured concentrations above the European air quality standards for PM10, PM2.5, O3, NO2 were reported by 21, 7, 24, and 22 European countries for 2019, respectively. Exceedances of the air quality standards for BaP, SO2, CO, and benzene were measured in, respectively, 14, 6, 3, and two European countries in 2019. Exceedances of European standards for toxic metals were reported by one country for Cd and Pb and by three countries for As and Ni.
ETC/ATNI
2021
Emission changes are the main driver of all air pollutant trends. For NO2 and PM10, both the GAM and the CTM results indicate that emission changes contribute to at least 90% of the 2000-2017 trend. For ozone peaks (as 4MDA8), meteorology can be important. The GAM model estimates that it contributes to an increase counteracting mitigation effort up to a magnitude of 20 to 80% (compared to the effect of emission and background changes) in Austria, Belgium, Czech Republic, France, and Italy. Given the good skill of the GAM model to capture meteorological effect, this estimate can be considered quite robust.
The relative contribution of agriculture and industry to the total PM10 mass has been reduced by around 30% for both sectors, but the similarity of evolution is not directly linked to the emission trends in the respective sectors. The relationship between emissions and concentrations is nonlinear and depends on availability of precursor gases to form ammonium sulphate and ammonium nitrate. The relative contribution of traffic sources to PM10 has been reduced with around 20%, while the trend attributed to residential heating is marginal. The heating sector has become a relatively more important contributor to the aerosol pollution and needs more attention. The model also indicates that the natural contributions (such as sea salt and dust) has had little impact on the long-term changes in PM10.
The analysis includes observational data only from stations with data available for at least 14 years in the period 2000-2017. This drastically reduces the number of monitoring sites included in the analysis and the spatial representativity of the assessment, with bias towards countries benefiting from a long-term monitoring network.
Further improvements of models as well as observational basis are needed to reduce the uncertainties. Understanding organic aerosols from the residential heating sector should be a priority.
ETC/ATNI
2021
Method for high resolution emission estimations from construction sites. Phase I: Mapping input data
This report presents the results from exploring the available input data to develop a model for estimating air pollutants and GHG-emissions based on a bottom-up approach, including both exhaust and non-exhaust emissions. The availability of
reliable input data is the limiting factor and the most critical part of designing such a bottom-up approach. In this study, we have focussed on assessing input data that allow defining; i) the exact location and area affected during building and construction; ii) the starting and finalization dates; iii) the type of construction activity; iv) the non-road mobile machinery (NRMM) activity within building and construction; v) roads in the vicinity of construction sites.
NILU
2021
SAMIRA-SAtellite Based Monitoring Initiative for Regional Air Quality
The satellite based monitoring initiative for regional air quality (SAMIRA) initiative was set up to demonstrate the exploitation of existing satellite data for monitoring regional and urban scale air quality. The project was carried out between May 2016 and December 2019 and focused on aerosol optical depth (AOD), particulate matter (PM), nitrogen dioxide (NO2), and sulfur dioxide (SO2). SAMIRA was built around several research tasks: 1. The spinning enhanced visible and infrared imager (SEVIRI) AOD optimal estimation algorithm was improved and geographically extended from Poland to Romania, the Czech Republic and Southern Norway. A near real-time retrieval was implemented and is currently operational. Correlation coefficients of 0.61 and 0.62 were found between SEVIRI AOD and ground-based sun-photometer for Romania and Poland, respectively. 2. A retrieval for ground-level concentrations of PM2.5 was implemented using the SEVIRI AOD in combination with WRF-Chem output. For representative sites a correlation of 0.56 and 0.49 between satellite-based PM2.5 and in situ PM2.5 was found for Poland and the Czech Republic, respectively. 3. An operational algorithm for data fusion was extended to make use of various satellite-based air quality products (NO2, SO2, AOD, PM2.5 and PM10). For the Czech Republic inclusion of satellite data improved mapping of NO2 in rural areas and on an annual basis in urban background areas. It slightly improved mapping of rural and urban background SO2. The use of satellites based AOD or PM2.5 improved mapping results for PM2.5 and PM10. 4. A geostatistical downscaling algorithm for satellite-based air quality products was developed to bridge the gap towards urban-scale applications. Initial testing using synthetic data was followed by applying the algorithm to OMI NO2 data with a direct comparison against high-resolution TROPOMI NO2 as a reference, thus allowing for a quantitative assessment of the algorithm performance and demonstrating significant accuracy improvements after downscaling. We can conclude that SAMIRA demonstrated the added value of using satellite data for regional- and urban-scale air quality monitoring.
2021
2021
The health risk related to exposure to air pollution (fine particulate matter - PM2.5, ozone - O3, and nitrogen dioxide - NO2) in 2019 was estimated in terms of number of premature deaths and years of life lost related to exposure to for 41 European countries, including the 27 EU Member States. In 2019, air pollution continued to drive a significant burden of premature death and disease in the 41 countries reporting to EEA: 373,000 premature deaths were attributed to chronic exposure to PM2.5; 47,700 premature deaths were attributed to chronic NO2 exposure; 19,070 premature deaths were attributed to acute O3 exposure. The analysis on the EU’s progress to reach the 2030 target established in the Zero Pollution Action Plan shows a steady decrease in the number of premature deaths along the years, and if it continues to fall at a comparable rate in the future, then the target would be achieved by 2032. Had the new WHO air quality guideline level for PM2.5 of 5 µg/m3 been attained already in 2019 everywhere in Europe, the number of estimated premature deaths would have been at least 58 % lower. On the other hand, the attainment of the EU limit value for PM2.5 of 25 µg/m3 would have left the estimated number of premature deaths unchanged in EU-27.
ETC/ATNI
2021
2021
Monitoring of the atmospheric ozone layer and natural ultraviolet radiation. Annual Report 2020.
This report summarizes the results from the Norwegian monitoring programme on stratospheric ozone and UV radiation measurements. The ozone layer has been measured at three locations since 1979: In Oslo/Kjeller, Tromsø/Andøya and Ny-Ålesund. The UV measurements started in 1995. The results show that there was a significant decrease in stratospheric ozone above Norway between 1979 and 1997. After that, the ozone layer stabilized at a level ~2% below pre-1980 level. 2020 was characterized by a strong, cold, and persistent Arctic stratospheric vortex, leading to extensive formation of Polar Stratospheric Clouds (PSCs, mother-of-pearl clouds) and chemical ozone destruction with very low ozone values and high UV levels in the exposed regions in the spring.
NILU
2021
2021
Status report of air quality in Europe for year 2020, using validated and up-to-date data
This report presents summarized information on the status of air quality in Europe in 2020, based on up-to date (i.e. prior to final quality control) and validated air quality monitoring data reported by the member and cooperating countries of the EEA. It aims at giving more timely and preliminary information on the status of ambient air quality in Europe in 2020 for five key air pollutants (PM10, PM2.5, O3, NO2 and SO2). The report also gives a preliminary assessment of the progress towards meeting the European air quality standards for the protection of health and the World Health Organization air quality guidelines, and compares the air quality status in 2020 with the previous three years. The preliminary data reported for 2020 shows that more than 10% of the monitoring stations exceeded the EU standards for PM10 and O3 and the WHO guidelines for PM2.5, PM10, O3 and SO2 in the EU-27 and UK. Exceedances of the NO2 limit value and WHO guideline still occur in 9 countries of the EU-27 and the UK.
ETC/ATNI
2021
2021
2021
Due to its comparatively high spatial resolution and its daily repeat frequency, the tropospheric nitrogen dioxide product provided by the TROPOspheric Monitoring Instrument (TROPOMI) onboard the Sentinel-5 Precursor platform has attracted significant attention for its potential for urban-scale monitoring of air quality. However, the exploitation of such data in, for example, operational assimilation of local-scale dispersion models is often complicated by substantial data gaps due to cloud cover or other retrieval limitations. These challenges are particularly prominent in high-latitude regions where significant cloud cover and high solar zenith angles are often prevalent. Using the example of Norway as a representative case for a high-latitude region, we here evaluate the spatiotemporal patterns in the availability of valid data from the operational TROPOMI tropospheric nitrogen dioxide (NO2) product over five urban areas (Oslo, Bergen, Trondheim, Stavanger, and Kristiansand) and a 2.5 year period from July 2018 through November 2020. Our results indicate that even for relatively clean environments such as small Norwegian cities, distinct spatial patterns of tropospheric NO2 are visible in long-term average datasets from TROPOMI. However, the availability of valid data on a daily level is limited by both cloud cover and solar zenith angle (during the winter months), causing the fraction of valid retrievals in each study site to vary from 20% to 50% on average. A temporal analysis shows that for our study sites and the selected period, the fraction of valid pixels in each domain shows a clear seasonal cycle reaching a maximum of 50% to 75% in the summer months and 0% to 20% in winter. The seasonal cycle in data availability shows the inverse behavior of NO2 pollution in Norway, which typically has its peak in the winter months. However, outside of the mid-winter period we find the TROPOMI NO2 product to provide sufficient data availability for detailed mapping and monitoring of NO2 pollution in the major urban areas in Norway and see potential for the use of the data in local-scale data assimilation and emission inversions applications.
2021
Implementing Citizen Science in Primary Schools: Engaging Young Children in Monitoring Air Pollution
Most European cities have air pollution levels that exceed the threshold for human health protection. Children are sensitive to air pollution and thus it is important to ensure they are not exposed to high concentrations of air pollutants. In order to make a positive change toward cleaner air, a joint effort is needed, involving all civil society actors. Schools and local communities have a decisive role, and can, for example, become engaged in citizen science initiatives and knowledge coproduction. In 2019, with the aim of raising awareness for air quality, NILU developed a citizen science toolbox to engage primary schools in monitoring air quality using a simple and affordable measuring method based on paper and petroleum jelly. This is a very visual method, where the students can clearly see differences from polluted and non-polluted places by looking at “how dirty” is the paper. In addition to the qualitative analysis, we have developed an air meter scale making possible for the students to obtain an indicative measurement of the air pollution level. The comparison between the paper and petroleum jelly method against reference PM10 data collected at two official air quality stations showed a good agreement. The method is a strong candidate for dust monitoring in citizen science projects, making participation possible and empowering people with simple tools at hand. The toolbox is targeted at primary schools and children aged 6–12 years, although it can easily be adapted to other age groups. The main objective of the toolbox is to involve young children who are usually not targeted in air quality citizen science activities, to develop research skills and critical thinking, as well as increase their awareness about the air they breathe. The toolbox is designed to engage students in hands-on activities, that challenge them to create hypotheses, design scientific experiments, draw conclusions and find creative solutions to the air pollution problem. The toolbox includes all the necessary material for the teachers, including guidance, background information and templates facilitating the incorporation in the school curricula. The toolbox was launched as part of the Oslo European Green Capital in March 2019 and was later included as part of the European Clean Air Day initiative coordinated by the European Citizen Science Association (ECSA) working group on air quality. A total of 30 schools and 60 4th grade classes (aged 8–9 years) participated in the Oslo campaign. The citizen science approach employed in the schools, combined the four key elements that promote knowledge integration: elicit ideas, add new ideas, distinguish among ideas and reflect and sort out ideas. Although the main goal of the study was to provide simple but robust tools for engaging young children in air quality monitoring, we also carried out ex-ante and ex-post evaluations in 12 of the participating classes using a 10-question multiple choice test to have an indication of the contribution of the activity to knowledge integration. The results show that there is an increase in the number of correct answers, as well as a reduction in the misconceptions after conducting the activity. These results indicate that applying a citizen science approach improved science instruction and helped knowledge integration by including students' views and taking advantage of the diverse ideas students generated. Citizen science gives learners an insight into the ways that scientists generate solutions for societal problems. But more important, citizen science provides a way to differ from the classic view of the learner as an absorber of information, by considering the social context of instruction and making the topic personally relevant.
2021