A. C. Carvalho

Air quality management in Portugal: example of needs and available tools

The Framework Directive (FWD) and the proposed Daughter Directives are the newest legislative instruments concerning a new political strategy and air quality management approach for Europe. Additionally, the member countries of the United Nations Economic Commission for Europe have included the concepts of critical load and level for planning air pollution abatement strategies and as a base of international agreements concerning limitation of the emissions of air pollutants. These concepts imply an accurate knowledge about pollutants deposition fluxes. The paper describes the main needs and the tools available to define a strategy of air quality management in Portugal. Two study cases are presented: (1) extensive monitoring plan to assess the impact of an urban incinerator plant; and (2) contribution to a methodology to estimate critical levels for a coastal region in Portugal. These different approaches allowed illustrating the complexity of the implementation of an air pollution management strategy.

Forest Fires And Air Pollution:A Local And A Global Perspective

A numerical system developed to simulate the effects of forest fires in the air quality is presented. This system integrates several related features, like emissions and progression of forest fires, and atmospheric flow. The interaction between the fire and the atmospheric flow considered as crucial is also taken into account in the system. Aiming to estimate the contribution of forest fires to the air pollution, two study cases (a local and a global one) were analysed. The first one is related to urban/wildland forest fires. The Etoile fire, occurred during the summer of 97 near Marseille in France was studied attempting to estimate its effects on the air quality of the city. Results indicate a considerable impact on the quality of the air of the suburban area of Marseille. Concerning the global scale impact of forest fires, greenhouse gases (GHG) emissions from Brazilian fires in 1997 were calculated and compared to the annual global GHG anthropogenic emissions. The contribution of Brazilian fires to the greenhouse effect is significant. An analysis of forest fires GHG emissions, oriented toward the problem of global warming and the goals of Kyoto Protocol, is also presented.

Chemical Mechanisms in two Photochemical Modelling Systems: A Comparison Procedure

The main purpose of this study is the evaluation of different chemical mechanisms included in two Eulerian photochemical models, MARS and CAMx, comparing simulation results. Both mechanisms (KOREM and EMEP) included in MARS were applied, whereas concerning CAMx the tested mechanisms were the default Carbon Bond IV and the revised radical termination reactions for the same mechanism.

Climate Change and Fire Weather Risk

The climate and the meteorological conditions throughout the year are of extreme importance in the deflagration and propagation of forest fires. Using the registered data from meteorological stations and forecasts, it is possible to establish the denominated meteorological fire risk index. This, mathematically, translates the fire risk that a given region is subject to, taking into consideration only meteorological conditions. The probable climatic changes, related to the emission of greenhouse gases, may come to affect the fire risk of a given region. The approach adopted to evaluate the impact of climate change on the fire weather risk (FWR) over Portugal is based on a numerical downscaling technique (from global to regional scale). The results of a general circulation model, for presentday conditions and for a climate centred in the year 2050, are used as initial and boundary conditions for a mesoscale model of atmospheric flow. This was applied to an area including Continental Portugal, for both considered situations, in terms of global simulation. The information obtained has been used to calculate the FWR with reference to the two simulated situations. Two FWR indexes were applied, the Angstrom and the Lourenco indexes. Globally, the prognosis is for an increase in the meteorological fire risk in Continental Portugal, for a climate scenario corresponding to the year 2050.

Portuguese Power Plants Impact On Air Quality

Energy consumption in Portugal presented an increase of 45% in the last 12 years (1990-2001) and is expected to continue its growth along with gross domestic product (GDP). The electric energy sector is dominated by hydric and thermal production, being the later mainly dependent on coal and a major source of air pollutants. Consistent with the objectives of improving energy efficiency and mitigating environmental problems, Portugal has increased its efforts to diversify energy sources, in particular through the introduction of natural gas. In this scope, three study cases were carried out in order to assess the air quality impacts of the re-conversion and increase capacity of three existing power plants located in the Lisbon metropolitan area, the Porto metropolitan area and in the central part of Portugal. The mesoscale photochemical system MEMO/MARS was applied in order to evaluate the air quality, namely ozone concentrations in ambient air, in each of the three power plant domains of influence. It was concluded that the power plants under study could increase their production capacity and fulfil the former national legislation commitments concerning ozone air quality standards. However, according to the Air Quality Framework Directive 2002/3/CE, recently enforced by national law, the new alert threshold for ozone (240 µg.m -3 ) will be exceeded in some episodic situations.

Air Quality Study over the Atlantic Coast of Iberian Peninsula

The west coast of Iberian Peninsula, surrounded by the Atlantic Ocean, is characterized by complex topography and some favourable synoptical situations, which imply the appearance of mesoscale circulations strongly influencing the transport of pollutants. On the other hand, the regions of Galicia (NW Spain), and the North of Portugal, have important air pollutants sources (power plants, chemical industries, traffic and biogenic emissions), all of them contributing to the air quality along the Atlantic coast and even affecting the centre of the Iberian Peninsula.

Sensitivity tests of MM5 modelling system over a coastal region in Portugal

The west coast of Iberian Peninsula, surrounded by the Atlantic Ocean, is characterized by complex topography and some favorable synoptical situations, which imply the occurrence of mesoscale circulations, namely sea/land breezes and anabatic and katabatic flo WS.Air quality standards are strongly influenced by these patterns leading to the enhancement of photochemical pollutants levels, In order to evaluate air quality levels in Aveiro, study region, a field campaign was carried out from 24* June to 2ndJuly of 2001, which covered the highest ozone (03) episode noticed in the region during the yetii of 2001. To correctly assess air quality over Aveiro region not only measurements are required but also the application of an integrated system of meteorological and photochemical models. Aiming to achieve more satisfactory air quality results both models must be evaluated over the interested region. Accordingly, meteorological model evaluation should be performed firstly. In this scope, the Pennsylvania State University/National Center for Atmospheric Research Mesoscale Meteorology Model (~M5) was applied using its nesting capabilities. Sensitivity analyses were also done in order to better understand how grid size influences model results and its behaviour under distinct meteorological situations. MM5 modelling system was applied to two 48 hours periods during summer 2001, in the North part of Portugal. MM5 application to this region presented a good skill when simulating anticyclone conditions. This study should be considered as pilot, because other

A modelling system for air quality management

To develop effective air quality management strategies at regional and urban levels requires the preparation of several actions belonging to different scientific areas and analysis of their complex interactions. A well-structured management system must be based on efficient tools that integrate diverse sets of information - emissions, traffic, meteorological variables and air quality data. Ideally, such a system should include appropriate modelling tools that could be used to perform spatial interpolation and air quality forecasts. This paper will describe the modelling system developed for predicting the emissions (emission pre-processor), dispersion and chemical transformation of pollutants in urban areas and its application for two sites in Portugal (Lisbon and Oporto). For predicting the concentration fields, all categories of sources are taken into account, namely stationary point and area sources and traffic. This allows the construction of an urban air quality management system for decision support.