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In the framework of the Forum for Air Quality Modelling in Europe (FAIRMODE), a modelling intercomparison exercise for computing NO2 long-term average concentrations in urban districts with a very high spatial resolution was carried out. This exercise was undertaken for a district of Antwerp (Belgium). Air quality data includes data recorded in air quality monitoring stations and 73 passive samplers deployed during one-month period in 2016. The modelling domain was 800 × 800 m2. Nine modelling teams participated in this exercise providing results from fifteen different modelling applications based on different kinds of model approaches (CFD – Computational Fluid Dynamics-, Lagrangian, Gaussian, and Artificial Intelligence). Some approaches consisted of models running the complete one-month period on an hourly basis, but most others used a scenario approach, which relies on simulations of scenarios representative of wind conditions combined with post-processing to retrieve a one-month average of NO2 concentrations.
The objective of this study is to evaluate what type of modelling system is better suited to get a good estimate of long-term averages in complex urban districts. This is very important for air quality assessment under the European ambient air quality directives. The time evolution of NO2 hourly concentrations during a day of relative high pollution was rather well estimated by all models. Relative to high resolution spatial distribution of one-month NO2 averaged concentrations, Gaussian models were not able to give detailed information, unless they include building data and street-canyon parameterizations. The models that account for complex urban geometries (i.e. CFD, Lagrangian, and AI models) appear to provide better estimates of the spatial distribution of one-month NO2 averages concentrations in the urban canopy. Approaches based on steady CFD-RANS (Reynolds Averaged Navier Stokes) model simulations of meteorological scenarios seem to provide good results with similar quality to those obtained with an unsteady one-month period CFD-RANS simulations.
2024
Electronic waste (e-waste) is informally processed and recycled in Agbogbloshie in Accra (Ghana), which may be the largest such site in West Africa. This industry can lead to significant environmental contamination. In this study, surface dust samples were collected at a range of sites within Accra to establish the offsite consequences of such activities. Fifty-one samples were collected and analysed for 69 elements by ICP-mass spectrometry after nitric acid digestion. The data indicated a significant enrichment in metals associated with solder and copper wire at the site itself and a downwind dispersion of this source material to a distance of approximately 2.0 km. Chlorine and bromine were also elevated at this site as residues from polyvinyl chloride combustion and flame retardants respectively. The elemental composition indicated that only low technology electrical equipment was being treated this way. Multivariate statistical analyses by principal components analysis and polytopic vector analysis identified three sources contributing to the system; (i) burn site residue dispersing within 2 km from the source site, (ii) marine matter on the beaches alone and (iii) the baseline soil conditions of the city of Accra. Risk ratios and hazard quotients developed from the measured concentrations indicated that copper was providing the greatest risk to inhabitants in most cases although nickel, vanadium, chromium and zinc also contributed.
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Using life cycle assessment to inform municipal climate mitigation planning
Local governments can play a key role in reducing emissions associated with local energy use. 17 Polish municipalities provided data on energy use and CO2 emissions for 2015. Life Cycle Assessment (LCA) was used to calculate lifecycle impact indicators for greenhouse gases, particulate matter, acidification and eutrophication associated with the annual energy demand in each municipality. Results showed that impacts from energy use increase almost proportionally with total energy used in the participating municipalities due to the heavy reliance on fossil fuels. Analysis of two municipalities of similar size showed that impacts can be attributed to different usage sectors. For one municipality, energy plans should focus on reducing emissions from private transport and associated fuel use. For the other, energy plans should focus on reducing energy demand from residential buildings. This means that a ‘one-size-fits-all’ energy plan, which may be developed at a national level, would not fit all municipalities. The application of LCA allows for identifying and informing energy planning with impact reduction potential for multiple environmental pressures. Analysis of the provided energy use and CO2 data showed large uncertainties in CO2 emission intensities and allowing for sufficient time and guidance in the energy and emissions accounting is recommended.
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2021
Utbedret E6 øst for Trondheim. Beregnet luftkvalitet 2040. NILU OR
Utbredelse av Rød og Gul sone for luftkvalitet er beregnet for ombygd E6 øst for Trondheim. Beregningene er basert på modellering av utslipp og spredning fra veg, samt estimat for bakgrunnskonsentrasjoner. Gul sone strekker seg opptil 80 m ut fra vegkant.
2015
Utbygging av etappe 1 i Bjørvika. Beregning av luftforurensning. NILU OR
Beregninger av trafikkforurensning i forbindelse med utbygging av etappe 1 i Bjørvika er utført for nitrøse gasser og svevestøv. Beregningene viser at områder med høye konsentrasjoner er begrenset til sonen mellom Ekebergtunnelen og Festningstunnelens forlengelse.
2000
Utfasing av oljefyring. Konsentrasjonsbidrag til PM10 og NO2 i Oslo. NILU OR
Astma- og Allergiforbundet og NILU - Norsk institutt for luftforskning har gjennomført en studie for å kartlegge hvilke konsekvenser utfasing av oljefyringsanlegg vil ha på lokal luftkvalitet i Oslo.
For døgnmiddelverdier av PM10 viser beregningene at økt bruk av biobrensel (pellets) vil føre til en signifikant økning av områder med døgnmiddel-konsentrasjoner over 35µg/m3, tilsvarende «Gul» sone» i Retningslinjer for behandling av luftkvalitet i arealplanlegging.
Utslippsøkningen av PM10 ved erstatning av all oljefyring med pellets er av samme størrelse som utslippsreduksjonen ved innføring av rentbrennende ovner for vedfyring i boliger (kvantifisert i framskrivingene for 2020).
2013