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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 km 2 ) 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 NO 2 and PM10 are located over international shipping routes and major ports, while O 3 concentrations are impacted in a larger area. The modelling results also indicate that shipping emissions are responsible for deltas in the concentration of NO 2 higher than 20% over specific urban areas located in the west coast of Portugal, and less than 5% for PM10. For O 3 the relative contribution is low (around 2%) but this contribution is also observed at locations more than 50 km from the coast. [ABSTRACT FROM AUTHOR]

This work aimed to assess the effectiveness of several resilience strategies to mitigate extreme urban heat episodes in Porto (Portugal). Different resilience scenarios were studied with the WRF urban modelling system, using as case-study a future heat wave occurring in Porto urban area. The resilience factors considered were the increase of urban green areas and the application of cool (green and white) roofs. The results showed that the most effective resilience strategies to mitigate high urban temperatures are the application of cool roofs. These resilience strategies produced the strongest reduction in the average and maximum surface temperatures over Porto urban area under a future heat wave. Considering that white roofs are considerably easier and cheaper to apply in urban areas than green roofs, this resilience strategy can be seen as the most viable, cost-effective and economically attractive approach for mitigating extreme urban temperatures. This study proposed several different urban resilience strategies to extreme temperature episodes for the first time for Porto urban area, proved their effectiveness and compared their ability to reduce urban heat. Such findings can be of great importance for Porto urban planning stakeholders given the expected increase in the heat waves frequency and intensity in future climate. [ABSTRACT FROM AUTHOR]

Air pollution is a major environmental health problem. The current Directive 2008/50/EC on ambient air quality and cleaner air for Europe establishes the need to reduce pollution to levels which minimise harmful effects on human health, paying particular attention to sensitive populations, and the environment as a whole, to improve the monitoring and assessment of air quality including the deposition of pollutants and to provide information to the public. This work presents an overview of the major guidelines of the Air Quality Directive concerning modelling and monitoring techniques and of current European initiatives on the subject. Also identifies the new challenges for the forthcoming directive, namely on the combined use of monitoring and modelling techniques and also on human exposure assessment. These challenges are illustrated by novel monitoring and modelling assessment approaches and innovative exposure assessment methodologies, for which selected examples are provided. A methodology to use monitoring data to improve AQ modelling performance was proposed using a set of statistical methods of data fusion, in which the bias correction technique RAT04 achieve the best performance. Moreover, methodologies based on personal monitoring, with AQ sensors, and/or on human exposure modelling, appear as tools for a more accurate exposure assessment. [ABSTRACT FROM AUTHOR]

This study aims to assess the influence of the use of a B20 fuel by road transports on urban air quality. For this purpose emission scenarios were designed and their impacts on air quality assessed using the WRF-EURAD modelling system applied over the Porto urban area. The scenarios consider emissions of CO, NOx, NMVOC, PM10, PM2.5, formaldehyde, acetaldehyde, acrolein and benzene from the use of pure diesel (reference scenario) and the use of a diesel blended with 20%(v/v) of biodiesel (B20 scenario). The results reveal that the use of B20 fuels improves the air quality over the Porto urban area, reducing the concentrations of most of the studied pollutants, with the exception of NO2. However, the concentrations vary in a small amount. Despite carbonyl compound emissions not being considered as individual input for the WRF-EURAD numerical modelling system, the equivalent ozone production estimated from the compound's emission variations indicate that the use of B20 can increase the O3 concentrations over the Porto urban area. [ABSTRACT FROM AUTHOR]

This study aims to assess the influence of the use of a B20 fuel by road transports on urban air quality. For this purpose emission scenarios were designed and their impacts on air quality assessed using the WRF-EURAD modelling system applied over the Porto urban area. The scenarios consider emissions of CO, NOx, NMVOC, PM10, PM2.5, formaldehyde, acetaldehyde, acrolein and benzene from the use of pure diesel (reference scenario) and the use of a diesel blended with 20%(v/v) of biodiesel (B20 scenario). The results reveal that the use of B20 fuels improves the air quality over the Porto urban area, reducing the concentrations of most of the studied pollutants, with the exception of NO2. However, the concentrations vary in a small amount. Despite carbonyl compound emissions not being considered as individual input for the WRF-EURAD numerical modelling system, the equivalent ozone production estimated from the compound's emission variations indicate that the use of B20 can increase the O3 concentrations over the Porto urban area. [ABSTRACT FROM AUTHOR]

According to the European Air Quality (AQ) Directive, member states must annually report their AQ to the European Commission (EC). This report can be based on modelling data if the concentration levels do not exceed the established lower assessment thresholds (LAT), or on combined data from modelling and monitoring systems (supplementary assessment methods) if concentrations levels are below the upper assessment threshold (UAT). This work presents and applies a methodology that combines air pollutant concentration values from monitored data and from a numerical modelling system to deliver AQ information for Portugal in 2010. This methodology produces improved information, especially for areas where the amount of fixed monitoring stations is sparse or non-existent, allowing obtaining a better and broader overview of the AQ in Portugal to support AQ reporting to the European Commission. [ABSTRACT FROM AUTHOR]

A very high ozone episode with observed hourly values above 350 μg m−3 occurred in July 2005 at the Lamas d’Olo air quality monitoring station, located in a mountainous area in the north of Portugal. Aiming to identify the origin and formation of this ozone-rich episode, a statistical analysis and a modelling approach were applied. A cross-spectrum analysis in the frequency domain and a synoptic analysis of the meteorological and air quality time series were performed. In order to go further in this analysis, a numerical modelling approach was applied. The results indicate that the transport of ozone and its precursors is the main responsible for the high ozone concentrations. Together with the local mountain breeze and subsidence conditions, the sea-breeze circulation transporting pollutants from the coastal urban and industrialized areas that reach the site during late afternoon turn out to be the driving forces for the ozone peaks. [Copyright &y& Elsevier]

PM10 limit values have been surpassed in the northern region of Portugal, and, according to European legislation, Plans and Programmes (PP) must be designed and implemented to reduce those PM10 levels. The Air Pollution Model (TAPM) was applied over the study region, to the year 2004, for the reference situation with the current PM10 emissions; and, for the reduction scenario with PM10 emissions re-estimated considering the implementation of all measures, in order to investigate the impact on air quality of all PP measures. The results point to a 19% reduction in the PM10 levels over the Porto urban area. [ABSTRACT FROM AUTHOR]

Abstract: Climate change alone may deeply impact air quality levels in the atmosphere because the changes in the meteorological conditions will induce changes on the transport, dispersion and transformation of air pollutants. The aim of this work was to evaluate the impact of climate change on the air quality over Europe and Portugal, using a reference year (year 1990) and a IPCC SRES A2 year (year 2100). The Hadley Centre global atmospheric circulation model (HadAM3P) was used to provide results for these two climatic scenarios, which were then used as synoptic forcing for the MM5-CHIMERE air quality modelling system. In order to assess the contribution of future climate change on O3 and PM concentrations, no changes in regional emissions were assumed and only climate change forcing was considered. The modelling results suggest that the O3 monthly mean levels in the atmosphere may increase almost 50μgm−3 across Europe in July under the IPCC SRES A2 scenario. In Portugal, this increase may reach 20μgm−3. The changes of PM10 monthly average values over Europe will depend on the region. The increase in PM10 concentrations during specific months could be explained by the average reduction of the boundary layer height and wind speed. [ABSTRACT FROM AUTHOR]

A Gaussian plume model was modified to simulate the dispersion of non-reactive air pollutants under non-homogeneous wind conditions through a multi-puff approach. It was applied to the city of Lisbon and evaluated by comparison with measured sulphur dioxide data, showing a reasonable skill to estimate the transport and dispersion of pollutants under complex wind field and different atmospheric conditions. The modelling results were integrated with observed data, based on correlation functions determined from historical values, to obtain the improved analytical results by using optimal interpolation. A significant improvement over the predictions by the Gaussian puff model alone was achieved. [ABSTRACT FROM AUTHOR]

A Gaussian plume model was modified to simulate the dispersion of non-reactive air pollutants under non-homogeneous wind conditions through a multi-puff approach. It was applied to the city of Lisbon and evaluated by comparison with measured sulphur dioxide data, showing a reasonable skill to estimate the transport and dispersion of pollutants under complex wind field and different atmospheric conditions. The modelling results were integrated with observed data, based on correlation functions determined from historical values, to obtain the improved analytical results by using optimal interpolation. A significant improvement over the predictions by the Gaussian puff model alone was achieved. [ABSTRACT FROM AUTHOR]

Abstract: 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. [Copyright &y& Elsevier]

• Building arrangement has a strong impact on the turbulent flow dynamics. • Flow dynamics patterns confirm the citizens' perception of wind discomfort. • Highest wind speeds are recorded within the auditorium. • Countermeasures are effective in improving comfort of the built environment. • Need for regulations concerning pedestrian wind comfort criteria. The complexity of the built environment plays an essential role on the local urban microclimate. Therefore, this work aims to assess the impact of buildings arrangement on the overall turbulent flow dynamics. This study is conducted for the neighborhood of an open auditorium located in an urban area. A set of experiments were accomplished using a wind tunnel, together with a set of Computational Fluid Dynamics (CFD) simulations. Both the experiments and the CFD simulations were carried out for a set of meteorological conditions identified as prevailing in the auditorium area. The physical and numerical approaches were used to assess the wind patterns for the reference scenario. Furthermore, a series of mitigation measures was simulated to evaluate their effectiveness in reducing the wind speed at pedestrian level in the neighborhood. The overall results emphasize the role of the mitigation measures to reduce wind speed and potentially improve pedestrian wind comfort levels in the auditorium. The originality of this paper relies on the design and test of the set of proposed mitigation measures, through the combination of complementary tools, as well as the expertise of distinct practitioners, and their insights regarding their effectiveness. [ABSTRACT FROM AUTHOR]

Urban areas, home to over half of the world's population, are at the forefront of climate change impacts and adaptation issues. Planning sustainable cities for the future requires not only a clear understanding of how climate change will influence urban areas but also how urban areas influence the local climate. This paper validates the Surface Urban Energy and Water Balance Scheme (SUEWS) model at an urban and a suburban site in Portugal, through five months of simulations, with forcing data from the Weather Research and Forecasting Model (WRF). SUEWS is tested against direct flux measurements carried out at the two study areas. The surface energy fluxes are also analysed in terms of the land cover characteristics of each study area, to understand the influence of the surface on the energy balance. At both sites SUEWS is able to simulate the turbulent sensible and latent heat fluxes and reproduces the diurnal cycle of the turbulent fluxes, but shows a consistent overestimation of the sensible heat flux. In terms of the latent heat flux, underestimation at the urban site and overestimation at the suburban site are evident. These results enable the use of WRF-SUEWS for emerging applications, such as, assessment of urban planning measures or assessment of urban climate under climate change scenarios. • Assessment of energy fluxes behaviour using both modelling and measuring approaches. • Land cover characteristics alters the partitioning of the energy fluxes. • Changes in the turbulent sensible and latent heat fluxes were found between the two study areas. • Understanding the behaviour of energy fluxes allows these to be used as a tool to evaluate the urban climate. [ABSTRACT FROM AUTHOR]

The performance of WRF model was investigated for the simulation of urban microclimate, with particular focus on energy fluxes, using different urban surface parameterizations. The model performance was evaluated using measurements carried out between August and December 2014 in Portugal. Several simulations were performed over two different areas, Porto urban area and Aveiro suburban area, for the entire measurement period. Distinct simulations were performed using different urban parametrizations: (i) the Noah Land Surface Model (LSM); (ii) a single-layer urban canopy model (UCM); and (iii) a modelling system composed by WRF and SUEWS models (WRF-SUEWS). The results showed that both UCM and SUEWS are able to simulate the energy partitioning over the low and high intensity residential. At the low intensity residential area, the majority of energy is partitioned to latent heat flux, accounting on average for 47% and 49% of the daytime available energy, for UCM and SUEWS, respectively. At the high intensity residential area, the greatest share of energy goes to sensible heat flux (42% [UCM] and 50% [SUEWS]), followed by the storage heat flux (33% [UCM] and 43% [SUEWS]). For both areas, a completely different energy partitioning was obtained when the LSM was used. The analysis performed showed that the UCM are able to provide a more accurate turbulent energy partitioning (sensible and latent heat), which contribute to enhance the urban microclimate simulation results; the systematic model biases in the LSM simulation was reduced by 1–2 °C in air temperature and by 0.5–1 m s−1 in wind speeds at near surface layer, on average, depending on the urban density. The overall results suggest that an appropriate representation of urban physical processes are crucial to improve numerical tools suited for the modelling of the urban atmospheric boundary layer. • Assessment of different urban surface parameterizations using measured data • Different urban surface parameterizations change the meteorological variables and energy fluxes results • The intensity level of built-up areas changes the behaviour of energy fluxes. • A more realistic representation of turbulent energy partition improves meteorological results. • WRF-UCM shows a high ability to represent the urban physical processes. [ABSTRACT FROM AUTHOR]

Focuses on the development of a modeling system for air quality management. Requirement for the development of the model for air quality management; Role of the model in the prediction of emissions of pollutants.

The development of a second generation Gaussian dispersion model (POLARIS) has been carried out. This model is significantly different from traditional Gaussian dispersion models, because its dispersion parameters have a continuous variation with the atmospheric stability. The new model was applied to the region of Setubal. The fossil fuel power plant in this region was taken as a point source, and data from 1993 were used. The results obtained using POLARIS were compared with air quality data and with results obtained from the POLUX and ISCST models for the same conditions. In terms of the statistical parameters, NMSE (normalized mean square error) and correlation coefficients, it can be seen that POLARIS gives the best approximation to the measured data. It also can be seen that POLARIS provides more results within a `factor of two', related to the measured concentrations, than theother two models for Setubal case. [ABSTRACT FROM AUTHOR]