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Air pollution concentrations were estimated the dispersion models as well as the emissions inventories compiled in AirQUIS for Dhaka and Chittagong. Meteorological data were generated from TAPM. Concentration plots for PM10, PM2.5 and SO2 and NO2 were presented for both cities. A scenario for 2020 was developed based on a combination of projected mitigation measures and sector growth based on GDP and population growth rates. In addition, health impacts were assessed based on methodologies from previous studies performed in Asia.
Results show that in general the PM2.5 and PM10 concentration distributions are closely linked to the emissions from brick kilns in the Dhaka area, while in Chittagong the impacts are more spread between the urban sources, brick, and industry and traffic sources. Results also show that PM10 and PM2.5 concentrations exceeds annual limit values, and that the dry season is most critical when it comes to high concentrations of PM10 and PM2.5.
2014
2009
Modelled sources of airborne microplastics collected at a remote Southern Hemisphere site
Airborne microplastics have emerged in recent years as ubiquitous atmospheric pollutants. However, data from the Southern Hemisphere, and remote regions in particular, are sparse. Here, we report airborne microplastic deposition fluxes measured during a five-week sampling campaign at a remote site in the foothills of the Southern Alps of New Zealand. Samples were collected over 24-hour periods for the first week and for 7-day periods thereafter. On average, atmospheric microplastic (MP) deposition fluxes were six times larger during the 24-hour sampling periods (150 MP m−2 day−1) than during the 7-day sampling periods (26 MP m−2 day−1), highlighting the importance of sampling frequency and deposition collector design to limit particle resuspension. Previous studies, many of which used weekly sampling frequencies or longer, may have substantially underestimated atmospheric microplastic deposition fluxes, depending on the study design. To identify likely sources of deposited microplastics, we performed simulations with a global dispersion model coupled with an emissions inventory of airborne microplastics. Modelled deposition fluxes are in good agreement with observations, highlighting the potential for this method in tracing sources of deposited microplastics globally. Modelling indicates that sea-spray was the dominant source when microplastics underwent long-range atmospheric transport, with a small contribution from road dust.
2024
2014
2014
2010
2011
NILU - Norsk institutt for luftforskning har beregnet konsentrasjoner av NO2, SO2 og PM10 i luft, samt nitrogen- og svovelavsetning som følge av utslipp til luft fra Hammerfest LNG med tilhørende skipstrafikk. Beregningene viser at konsentrasjon av NO2 kan overskride Klifs anbefalte luftkvalitetskriterier, men ikke EUs grenseverdier eller Nasjonale mål. For SO2 og PM10 er det ikke overskridelser av noen grenseverdier. Videre viser beregningene en maksimal avsetning på 14 mg N /m2 og 11 mg S /m2 per år.
2012
Modellering av vulkanaske i norsk luftfrom. Pkt. 1.3 Enkle forbedringer av utslippsestimat. NILU OR
Rapporten beskriver hvordan en transportmodell brukes til å simulere utslipp av aske fra vulkanutbrudd og hvordan askeutslippene kan beskrives i modellen. En rekke metoder for beregning av askeutslipp er presentert og utarbeidelse av forbedrede askeutslippestimat ved manuell analyse av satellittdata er presentert.
2013
De tre transportmodellene EEMEP, SNAP og FLEXPART har simulert askespredning og avsetning fra Eyjafjalljökull utbruddet i 2010. Alle modellene har blitt kjørt med identisk kildeledd, og modellresultatene har blitt sammenlignet i detalj opp mot hverandre og opp mot observasjoner. Dette gir en økt forståelse av modellenes evne til å simulere askespredning, og av ulikhetene mellom modellresultater som ofte oppstår, spesielt under en askesituasjon i nær sanntid.
2014
2017
Modelling and mapping of degradation of built environment from available data and GIS based information tools. Umwelt-bundesamt. Texte 24/99
1999
2014
2025
Modelling Arctic lower-tropospheric ozone: processes controlling seasonal variations
Abstract. Previous assessments on modelling Arctic tropospheric ozone (O3) have shown that most atmospheric models continue to experience difficulties in simulating tropospheric O3 in the Arctic, particularly in capturing the seasonal variations at coastal sites, primarily attributed to the lack of representation of surface bromine chemistry in the Arctic. In this study, two independent chemical transport models (CTMs), DEHM (Danish Eulerian Hemispheric Model) and GEM-MACH (Global Environmental Multi-scale – Modelling Air quality and Chemistry), were used to simulate Arctic lower-tropospheric O3 for the year 2015 at considerably higher horizontal resolutions (25 and 15 km, respectively) than the large-scale models in the previous assessments. Both models include bromine chemistry but with different mechanistic representations of bromine sources from snow- and ice-covered polar regions: a blowing-snow bromine source mechanism in DEHM and a snowpack bromine source mechanism in GEM-MACH. Model results were compared with a suite of observations in the Arctic, including hourly observations from surface sites and mobile platforms (buoys and ships) and ozonesonde profiles, to evaluate models' ability to simulate Arctic lower-tropospheric O3, particularly in capturing the seasonal variations and the key processes controlling these variations. Both models are found to behave quite similarly outside the spring period and are able to capture the observed overall surface O3 seasonal cycle and synoptic-scale variabilities, as well as the O3 vertical profiles in the Arctic. GEM-MACH (with the snowpack bromine source mechanism) was able to simulate most of the observed springtime ozone depletion events (ODEs) at the coastal and buoy sites well, while DEHM (with the blowing-snow bromine source mechanism) simulated much fewer ODEs. The present study demonstrates that the springtime O3 depletion process plays a central role in driving the surface O3 seasonal cycle in central Arctic, and that the bromine-mediated ODEs, while occurring most notably within the lowest few hundred metres of air above the Arctic Ocean, can induce a 5 %–7 % of loss in the total pan-Arctic tropospheric O3 burden during springtime. The model simulations also showed an overall enhancement in the pan-Arctic O3 concentration due to northern boreal wildfire emissions in summer 2015; the enhancement is more significant at higher altitudes. Higher O3 excess ratios (ΔO3/ΔCO) found aloft compared to near the surface indicate greater photochemical O3 production efficiency at higher altitudes in fire-impacted air masses. The model simulations further indicated an enhancement in NOy in the Arctic due to wildfires; a large portion of NOy produced from the wildfire emissions is found in the form of PAN that is transported to the Arctic, particularly at higher altitudes, potentially contributing to O3 production there.
2025
2015
1999
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