1,137 research outputs found

    How important are maritime emissions for the air quality: at European and national scale

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    Due to its dependence on fossil fuel combustion, emissions from the marine transport sector can significantly contribute to air pollution. This work aims to evaluate the impact of maritime transport emissions on air quality in Portugal using a numerical air quality modelling approach, with high-resolution emission data. Emissions from the European TNO inventory were compiled and pre-processed at hourly and high spatial (∼3 × 3 km2) resolutions. Scenarios with and without these maritime emissions were then simulated with the WRF-CHIMERE modelling system, extensively tested and validated for Portugal domain, in order to evaluate their impact on air quality. A simulation was performed for one year (2016) and the resulting differences were analysed in terms of spatial distribution, time series and deltas. The main deltas for NO2 and PM10 are located over international shipping routes and major ports, while O3 concentrations are impacted in a larger area. The modelling results also indicate that shipping emissions are responsible for deltas in the concentration of NO2 higher than 20% over specific urban areas located in the west coast of Portugal, and less than 5% for PM10. For O3 the relative contribution is low (around 2%) but this contribution is also observed at locations more than 50 km from the coast.Thanks are due for the financial support to FCT/MEC through national funds, and the co-funding by the FEDER, within the PT2020 Partnership Agreement and Compete 2020, for the AIRSHIP project (PTDC/AAG-MAA/2569/2014 - POCI-01-0145-FEDER-016752) and CESAM (UID/AMB/50017 - POCI-01-0145-FEDER-007638).publishe

    Portuguese industry and the EU trade emissions directive: development and analysis of CO2 emission scenarios

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    In December 1997, the Kyoto Protocol was adopted, setting limits on the greenhouse gas (GHG) emissions of industrialized countries. The European Union agreed to reduce its emissions of GHG by 8% during the period 2008–2012 in comparison to their 1990 levels. Subsequently, in a scheme known as “burden-sharing”, Portugal was allowed to increase its emissions by 27% in the same period. Large industrial facilities are responsible for a significant share of carbon dioxide (CO2) emissions and are object of a European Directive (2003/87/EC) establishing the scheme for GHG emission allowance trading within the European Union, launched with the purpose of allowing the reduction of GHG emissions cost-effectively. According to the Directive, Member States shall develop a National Allocation Plan (NAP) stating the total quantity of allowances that each one intends to allocate and how it proposes to allocate them among the activities included in the trading scheme. In this work, an analysis of the Portuguese industry is performed, focused on the energy consumption and CO2 emissions levels in the period 1990–2001 and on the estimation of the two parameters for the period 2002–2012, considering different economic growth scenarios and investments on energy reduction technologies. Results show that all the analysed sectors present a significant growth in CO2 emissions, exceeding the limit established in the frame of the Kyoto Protocol, and that measures other than cost-effective energy technologies will have to be implemented

    usefulness of testing with PEG 1500 extract

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    Background. Polyethylene glycol (PEG) is being used for first time as an excipient for mRNA anti-SARS-CoV-2 vaccines containing-PEG2000, highlighting it as a potential cause of anaphylaxis. Objective. To assess the usefulness of skin tests using PEG1500 extract in patients with suspected allergy to SARS-CoV-2 vaccines. Methods. We evaluated 126 patients with moderate-high risk of allergy to SARS-CoV-2 vaccines referred to our department from March-December 2021. Skin tests were performed with PEG1500 extract (Roxall), using a stepwise approach, with readings at 30 minutes: prick tests with 0.1%, 1% and 10% concentrations; if negative, intradermal tests with 0.0001%, 0.001% and 0.01% concentrations. The same protocol was applied to 5 healthy controls. Results. Six patients had positive immediate intradermal tests with PEG1500, all with severe PEG allergy: one with a near-fatal anaphylaxis after glucocorticoid injection containing-PEG3350 and five with systemic allergic reactions after mRNA vaccines containing-PEG2000 (Pfizer-BioNTech or Moderna). One patient developed anaphylaxis during intradermal test. These six patients were negative to polysorbate 80. The remaining 120 patients had negative tests to PEG1500; seven had positive tests to polysorbate 80. All controls had negative tests. Conclusions. To our knowledge this is the first study describing the allergy work-up testing with PEG1500 commercial extract in the scope of SARS-CoV-2 vaccination. The algorithm designed for skin tests revealed to be a useful tool. Severe PEG allergy was diagnosed in 5% of patients, contraindicating PEG-containing vaccines. PEG allergy was excluded in one hundred patients that afterwards took SARS-CoV-2 vaccines containing-PEG2000. Investigation should be conducted in specialized drug allergy centres.authorsversionpublishe

    Fatigue behaviour of nanoclay reinforced epoxy resin composites

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    Nanoparticle filling is a feasible way to increase the mechanical properties of polymer matrices. Abundant research work has been published in the last number of years concerning the enhancement of the mechanical properties of nanoparticle filled polymers, but only a reduced number of studies have been done focusing on the fatigue behaviour. This work analyses the influence of nanoclay reinforcement and water presence on the fatigue behaviour of epoxy matrices. The nanoparticles were dispersed into the epoxy resin using a direct mixing method. The dispersion and exfoliation of nanoparticles was characterised by X-ray diffraction (XRD) and transmission electron microscopy (TEM). Fatigue strength decreased with the nanoclay incorporation into the matrix. Fatigue life of nanoclay filled composites was significantly reduced by the notch effect and by the immersion in water

    Air quality modelling as a tool for sustainable urban traffic management

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    This work intends to assess the impact of road traffic management on urban air quality at the street level. At the core of the applied methodology is the numerical modelling of wind flow and air pollutants dispersion in a typical European urban environment. Through the application of a Computational Fluid Dynamics (CFD) model, the synergies between the 3D configuration of the street-canyon, in addition to the impacts on the dispersion of CO and PM10 emitted by vehicles, were evaluated. Air quality simulations were performed for a study domain of approximately 2501000 m2 in the downtown of a medium sized Portuguese town, with average daily traffic of 21,400 vehicles. Different traffic scenarios were analysed based on the modification of the number and location of traffic lanes for typical meteorological boundary conditions. Complex dispersion patterns were obtained due to the effect of buildings and trees on the wind flow. Moreover, simulations for the different scenarios have shown distinct behaviours of the air pollutants due to the prevailing wind direction and road positioning. It was concluded that, for typical conditions, the closure of the two traffic lanes located on the south side of the main avenue and the two adjacent streets is the best solution for air quality improvement. This scenario leads to a 31% reduction in CO and PM10 concentrations on the North sidewalk and 81% on the South sidewalk when comparing to present conditions. The other alternative leads to a reduction of, respectively, 70% and 20%. The first scenario also leads to maximum decreases of 57% and 59%, respectively, in the CO and PM10 peak concentrations. These conclusions stress the importance of integrating the knowledge provided by the application of CFD models in urban planning and road traffic management with the goal of promoting urban sustainability.publishe
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