Fant 9747 publikasjoner. Viser side 370 av 390:
We determine the global emission distribution of the potent greenhouse gas sulfur hexafluoride (SF6) for the period 2005–2021 using inverse modelling. The inversion is based on 50 d backward simulations with the Lagrangian particle dispersion model (LPDM) FLEXPART and on a comprehensive observation data set of SF6 mole fractions in which we combine continuous with flask measurements sampled at fixed surface locations and observations from aircraft and ship campaigns. We use a global-distribution-based (GDB) approach to determine baseline mole fractions directly from global SF6 mole fraction fields at the termination points of the backward trajectories. We compute these fields by performing an atmospheric SF6 re-analysis, assimilating global SF6 observations into modelled global three-dimensional mole fraction fields. Our inversion results are in excellent agreement with several regional inversion studies in the USA, Europe, and China. We find that (1) annual US SF6 emissions strongly decreased from 1.25 Gg in 2005 to 0.48 Gg in 2021; however, they were on average twice as high as the reported emissions to the United Nations. (2) SF6 emissions from EU countries show an average decreasing trend of −0.006 Gg yr−1 during the period 2005 to 2021, including a substantial drop in 2018. This drop is likely a direct result of the EU's F-gas regulation 517/2014, which bans the use of SF6 for recycling magnesium die-casting alloys as of 2018 and requires leak detection systems for electrical switch gear. (3) Chinese annual emissions grew from 1.28 Gg in 2005 to 5.16 Gg in 2021, with a trend of 0.21 Gg yr−1, which is even higher than the average global total emission trend of 0.20 Gg yr−1. (4) National reports for the USA, Europe, and China all underestimated their SF6 emissions. (5) Our results indicate increasing emissions in poorly monitored areas (e.g. India, Africa, and South America); however, these results are uncertain due to weak observational constraints, highlighting the need for enhanced monitoring in these areas. (6) Global total SF6 emissions are comparable to estimates in previous studies but are sensitive to a priori estimates due to the low network sensitivity in poorly monitored regions. (7) Monthly inversions indicate that SF6 emissions in the Northern Hemisphere were on average higher in summer than in winter throughout the study period.
2024
2024
2024
2024
2024
Disse miljøgiftene fant forskerne igjen i de ville dyrene
Norges forskningsråd
2024
Forecasting the Exceedances of PM2.5 in an Urban Area
Particular matter (PM) constitutes one of the major air pollutants. Human exposure to fine PM (PM with a median diameter less than or equal to 2.5 μm, PM2.5) has many negative and diverse outcomes for human health, such as respiratory mortality, lung cancer, etc. Accurate air-quality forecasting on a regional scale enables local agencies to design and apply appropriate policies (e.g., meet specific emissions limitations) to tackle the problem of air pollution. Under this framework, low-cost sensors have recently emerged as a valuable tool, facilitating the spatiotemporal monitoring of air pollution on a local scale. In this study, we present a deep learning approach (long short-term memory, LSTM) to forecast the intra-day air pollution exceedances across urban and suburban areas. The PM2.5 data used in this study were collected from 12 well-calibrated low-cost sensors (Purple Air) located in the greater area of the Municipality of Thermi in Thessaloniki, Greece. The LSTM-based methodology implements PM2.5 data as well as auxiliary data, meteorological variables from the Copernicus Atmosphere Monitoring Service (CAMS), which is operated by ECMWF, and time variables related to local emissions to enhance the air pollution forecasting performance. The accuracy of the model forecasts reported adequate results, revealing a correlation coefficient between the measured PM2.5 and the LSTM forecast data ranging between 0.67 and 0.94 for all time horizons, with a decreasing trend as the time horizon increases. Regarding air pollution exceedances, the LSTM forecasting system can correctly capture more than 70.0% of the air pollution exceedance events in the study region. The latter findings highlight the model’s capabilities to correctly detect possible WHO threshold exceedances and provide valuable information regarding local air quality.
MDPI
2024
2024
2024
European cities air quality ranking: a new methodology
The EEA has introduced the European City Air Quality Viewer, a tool to assess and compare air quality in European cities. However, this method provides an incomplete picture of air quality as it relies solely on PM2.5 data from monitoring stations, excluding cities lacking monitoring stations and other relevant pollutants such as NO2 and O3. A promising alternative to the current methodology is proposed to reduce these limitations, offering a comprehensive approach to assessing and comparing health risks linked to exposure to multiple pollutants in urban settings. Leveraging continuous air quality maps and population-weighted concentrations enhances coverage and consistency in risk estimation across cities. Additionally, it allows for ranking based on multiple pollutants, unlike the current method, which focuses solely on PM2.5 levels. This approach integrates mortality risk assessments associated with PM2.5, NO2, and O3 exposure, aligning with the Environmental Burden of Disease assessments published by the ETC HE, together with the EEA.
ETC/HE
2024
Hulun Lake, the largest inland steppe lake in China, is encountering severe water quality degradation. Estuaries play important roles in material and energetic exchange between rivers and lakes. The water quality at the estuaries of Hulun Lake directly reflects the impact of both human activities and natural factors on the lake’s overall water quality, especially during rainfall events. From July 28, 2021, to August 4, 2021, water samples from 62 sites were collected in the three estuaries of Hulun Lake before and after a moderate rainfall event. 13 water parameters, including dissolved oxygen (DO), Turbidity (Tur), Total Nitrogen (TN), Total Phosphorus (TP), Total Organic Nitrogen (TON), and Total Organic Phosphorus (TOP) were measured. The spatio-temporal distribution of water quality in the estuaries was assessed based on water quality index (WQI). Besides, an improved approach integrating stepwise linear regression (SLR) and principal component analysis (PCA) was utilized to construct a WQImin model for an effective assessment of water quality in these estuaries. Furthermore, the absolute principal component scores-multiple linear regression (APCS-MLR) model was employed to identify and quantify the environmental drivers underlying the water quality in the estuaries. The results of WQI indicated that the water quality of the sites in the estuaries of Hulun Lake was “medium” or “poor”, both before and after the rainfall, with a general deterioration in water quality in response to the rainfall. The simplified WQImin model consisted of 5 crucial parameters (i.e., TN, TP, ammonium (NH4+-N), Tur, and permanganate index (CODMn)), and it performed well without parameter weights. Spatial differences in some water parameters among the estuaries were detected, which were attributed to the natural factors and human activities upstream. The principal environmental factors affecting the water quality in the estuaries consisted of hydrodynamic processes, internal phosphorus release, external phosphorus input, external nitrogen input, nitrification in the estuaries, and external organic input and internal organic release. Therefore, we propose basin management strategies such as limiting grazing pressure, adopting enclosed pasture, wetland restoration, optimizing water renewal cycle in Hulun Lake, and transboundary water quality management to tackle water contamination in Hulun Lake.
Elsevier
2024
Monitoring air quality in ports and nearby cities is crucial to understanding the role of emissions from shipping and other port activities. This report analyzes air quality in 23 European ports, revealing limited observations in and around port areas. Only 5 of the 23 ports had at least one air quality sampling point for NO2 and PM10 inside the port area. Concentrations in nearby cities can be up to double (NO2) and 74% higher (PM10) when the wind comes from the port. EEA air quality maps showed higher annual mean NO2 concentrations in port areas compared to surrounding regions, with some ports exceeding the 2030 limit value of 20 µg/m³. Annual mean PM10 concentrations were also higher in port areas, with nine ports exceeding the new limit value. The limited number of sampling points makes it challenging to assess trends in NO2 and PM10 concentrations. International shipping emissions significantly contribute to NO2 levels in port cities, as shown by pollution episodes in Antwerpen and Barcelona.
ETC/HE
2024
2024
NILU har, på oppdrag fra Glasopor AS ved Onsøy i Fredrikstad, kartlagt utslipp av støv fra anlegget og effekter på ytre miljø. Bedriften ønsker å oppgradere anlegget og øke produksjonen og har søkt om ny utslippstillatelse. I den forbindelse har Statsforvalteren oppfølgende spørsmål med krav om dokumentasjon knyttet til utslipp av støv og påvirkning på ytre miljø. For å svare på disse spørsmålene har NILU gjennomført målinger, beregning av utslipp og spredningsberegninger. Rapporten skal inngå i dokumentasjonen som oversendes norske myndigheter.
NILU
2024