Found 9895 publications. Showing page 295 of 396:
American Geophysical Union (AGU)
2019
Environmental impacts of a chemical looping combustion power plant
Chemical Looping Combustion (CLC) is a promising CO2 capture option since it inherently separates CO2 from other flue components, theoretically with low energy penalty. Here, a Life Cycle Assessment model was developed of a theoretical hybrid CLC (HCLC) power plant facility utilising experimental data for CuO based oxygen carrier (OC) production and oxygen capacity. Power plant models with and without post-combustion CO2 capture, recognised as the most mature capture technology, acted as environmental performance targets. Results show that when OC is produced at lab-scale without optimisation, almost all (>99.9%) lifecycle impacts per kWh electricity from an HCLC plant derive from the specific OC material used, giving a total of ˜700 kg CO2eq/kWh. This is related to high electrical input required for OC processing, as well as high OC losses during production and from plant waste. Only when processing parameters are optimised and OC recycling from plant waste is implemented - reducing fresh OC needs – is the environmental impact lower than the conventional technologies studied (e.g. 0.2 kg CO2 eq/kWh vs. ˜0.3-1 kg CO2 eq/kWh, respectively). Further research should thus focus on identifying OCs that do not require energy intensive processing and can endure repeated cycles, allowing for recycling.
Elsevier
2019
To estimate the oxidative potential (OP) of particulate matter (PM), two commonly used cell-free, molecular probes were applied: dithiothreitol (DTT) and dichloro-dihydro-fluorescein diacetate (DCFH-DA), and their performance was compared with 9,10-bis (phenylethynyl) anthracene-nitroxide (BPEAnit). To the best of our knowledge, this is the first study in which the performance of the DTT and DCFH has been compared with the BPEAnit probe. The average concentrations of PM, organic carbon (OC) and elemental carbon (EC) for fine (PM2.5) and coarse (PM10) particles were determined. The results were 44.8 ± 13.7, 9.8 ± 5.1 and 9.3 ± 4.8 µg·m−3 for PM2.5 and 75.5 ± 25.1, 16.3 ± 8.7 and 11.8 ± 5.3 µg·m−3 for PM10, respectively, for PM, OC and EC. The water-soluble organic carbon (WSOC) fraction accounted for 42 ± 14% and 28 ± 9% of organic carbon in PM2.5 and PM10, respectively. The average volume normalized OP values for the three assays depended on both the sampling periods and the PM fractions. The OPBPEAnit had its peak at 2 p.m.; in the afternoon, it was three times higher compared to the morning and late afternoon values. The DCFH and BPEAnit results were correlated (r = 0.64), while there was no good agreement between the BPEAnit and the DTT (r = 0.14). The total organic content of PM does not necessarily represent oxidative capacity and it shows varying correlation with the OP. With respect to the two PM fractions studied, the OP was mostly associated with smaller particles.
MDPI
2019
2019
2019
Review of the Assessment of Industrial Emissions with Mosses
Commissioned by Norwegian Environmental Agency, NILU - Norwegian Institute for Air Research has surveyed the literature on the topic of “Assessment of industrial emissions using moss”. The purpose is to provide an overview of published knowledge on possible relationships between metal concentrations in moss and air quality, emissions, uptake in other organisms and impacts on environment and health. In addition, there was a request for information on whether other countries use moss surveys around industries and, if so, how the results are used by the authorities. The literature search resulted in 51 relevant publications, which mostly are from the period 2016-2019. The results of these publications show that moss is a good passive sampler for airborne contaminants and can provide valuable information on chemical signature and deposition of metals. No studies have been found that relates concentration in moss to air quality or amount emission from selected industries. A single 2019 study attempts to link moss concentration in context of health effects. A survey among the participating countries in ICP-Vegetation shows that results from moss surveys so far not have been used by authorities in a regulatory context.
NILU
2019
SESS report 2018. The State of Environmental Science in Svalbard – an annual report.
Svalbard Integrated Arctic Earth Observing System (SIOS)
2019
Air Quality in Ny-Ålesund. Monitoring of Local Air Quality 2018.
The concentrations of the measured components are generally low and below national limit values for the protection of
human health and critical levels for the protection of vegetation.
Wind from northern sectors gave the highest average concentrations of nitrogen oxides and sulphur dioxide, which
indicates the power station and the harbour as possible sources. The measurement results for CO2 show an annual variation with higher concentrations in the winter and lower in summer. Measured concentrations of CO were most likely caused by local snowmobile traffic.
NILU
2019
The Tibetan Plateau (TP) region, often referred to as the Third Pole, is the world's highest plateau and exerts a considerable influence on regional and global climate. The state of the snowpack over the TP is a major research focus due to its great impact on the headwaters of a dozen major Asian rivers. While many studies have attempted to validate atmospheric reanalyses over the TP area in terms of temperature or precipitation, there have been – remarkably – no studies aimed at systematically comparing the snow depth or snow cover in global reanalyses with satellite and in situ data. Yet, snow in reanalyses provides critical surface information for forecast systems from the medium to sub-seasonal timescales.
Here, snow depth and snow cover from four recent global reanalysis products, namely the European Centre for Medium-Range Weather Forecasts (ECMWF) ERA5 and ERA-Interim reanalyses, the Japanese 55-year Reanalysis (JRA-55) and the NASA Modern-Era Retrospective analysis for Research and Applications (MERRA-2), are inter-compared over the TP region. The reanalyses are evaluated against a set of 33 in situ station observations, as well as against the Interactive Multisensor Snow and Ice Mapping System (IMS) snow cover and a satellite microwave snow depth dataset. The high temporal correlation coefficient (0.78) between the IMS snow cover and the in situ observations provides confidence in the station data despite the relative paucity of in situ measurement sites and the harsh operating conditions.
While several reanalyses show a systematic overestimation of the snow depth or snow cover, the reanalyses that assimilate local in situ observations or IMS snow cover are better capable of representing the shallow, transient snowpack over the TP region. The latter point is clearly demonstrated by examining the family of reanalyses from the ECMWF, of which only the older ERA-Interim assimilated IMS snow cover at high altitudes, while ERA5 did not consider IMS snow cover for high altitudes. We further tested the sensitivity of the ERA5-Land model in offline experiments, assessing the impact of blown snow sublimation, snow cover to snow depth conversion and, more importantly, excessive snowfall. These results suggest that excessive snowfall might be the primary factor for the large overestimation of snow depth and cover in ERA5 reanalysis. Pending a solution for this common model precipitation bias over the Himalayas and the TP, future snow reanalyses that optimally combine the use of satellite snow cover and in situ snow depth observations in the assimilation and analysis cycles have the potential to improve medium-range to sub-seasonal forecasts for water resources applications.
European Geosciences Union (EGU)
2019
We present here emissions estimated from a newly developed emission model for residential wood combustion (RWC) at high spatial and temporal resolution, which we name the MetVed model. The model estimates hourly emissions resolved on a 250 m grid resolution for several compounds, including particulate matter (PM), black carbon (BC) and polycyclic aromatic hydrocarbons (PAHs) in Norway for a 12-year period. The model uses novel input data and calculation methods that combine databases built with an unprecedented high level of detail and near-national coverage. The model establishes wood burning potential at the grid based on the dependencies between variables that influence emissions: i.e. outdoor temperature, number of and type and size of dwellings, type of available heating technologies, distribution of wood-based heating installations and their associated emission factors. RWC activity with a 1 h temporal profile was produced by combining heating degree day and hourly and weekday activity profiles reported by wood consumers in official statistics. This approach results in an improved characterisation of the spatio-temporal distribution of wood use, and subsequently of emissions, required for urban air quality assessments. Whereas most variables are calculated based on bottom-up approaches on a 250 m spatial grid, the MetVed model is set up to use official wood consumption at the county level and then distributes consumption to individual grids proportional to the physical traits of the residences within it. MetVed combines consumption with official emission factors that makes the emissions also upward scalable from the 250 m grid to the national level.
The MetVed spatial distribution obtained was compared at the urban scale to other existing emissions at the same scale. The annual urban emissions, developed according to different spatial proxies, were found to have differences up to an order of magnitude. The MetVed total annual PM2.5 emissions in the urban domains compare well to emissions adjusted based on concentration measurements. In addition, hourly PM2.5 concentrations estimated by an Eulerian dispersion model using MetVed emissions were compared to measurements at air quality stations. Both hourly daily profiles and the seasonality of PM2.5 show a slight overestimation of PM2.5 levels. However, a comparison with black carbon from biomass burning and benzo(a)pyrene measurements indicates higher emissions during winter than that obtained by MetVed. The accuracy of urban emissions from RWC relies on the accuracy of the wood consumption (activity data), emission factors and the spatio-temporal distribution. While there are still knowledge gaps regarding emissions, MetVed represents a vast improvement in the spatial and temporal distribution of RWC.
2019
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.
Elsevier
2019
2019
2019