M. Coutinho

Forest fire emissions in Portugal: a contribution to global warming?

A forecast of expected evolution of carbon dioxide (CO(2)) emissions in Portugal between 1988 and 2010 is presented. Predictions show that CO(2) emissions will almost double in the next twenty years. The equivalent potential CO(2) emissions from nitrogen oxides (NO(x)) and volatile organic compounds (VOC), for a time horizon of 20 years, is also presented. NO(x) and VOC emissions seem to make a significant contribution to the global warming potential of Portuguese emissions. Estimates of CO(2) emissions due to forest fires have been made, oriented towards the study of the Portuguese contribution to the global warming. If the burned area exceeds 100 000 ha this contribution could reach 7% of the total Portuguese CO(2) emissions. The global warming potential of Portuguese forest emissions were also calculated. The climate change predicted to Portugal could be responsible for an increase in the forest fires and consequently for a greater contribution of its emissions to the total values. It was concluded that it is important to quantify emissions of the greenhouse gases, including the contribution of forest fire emissions, not only in Portugal, but in all the Southern European countries.

Long-term monitoring and seasonal analysis of polycyclic aromatic hydrocarbons (PAHs) measured over a decade in the ambient air of Porto, Portugal

The present paper reports the analytical results of PAHs concentrations in ambient air obtained in the PM10 and gas-phase, from 2004 to 2014, in Porto, Portugal. As part of a monitoring programme conducted by IDAD - Institute of Environment and Development and supported by the regional municipal solid waste (MSW) management authorities, an extensive database of PAH concentrations in ambient air was collected in Portos metropolitan area. During this period a total of 201 samples were collected in two sites classified as suburban. Analytical results showed a clear decreasing trend of total PAHs (∑PAH) and benzo[a]pyrene (BaP) levels during the period of study, especially in the first years of monitoring. The average annual concentrations of BaP were, throughout the monitoring period, lower than the target value for the annual average (1 ng m(-3)) defined in the European legislation. PAHs levels showed a strong seasonality, with higher concentrations values during the colder months. The winter/summer ratio of ∑PAH for the eleven years of study was 5, revealing the seasonal variation of PAHs in the studied area. The estimated toxic equivalency factors (TEFs) used to assess the contribution of the carcinogenic potential, confirmed a significant presence of the moderately active carcinogenic BaP and dibenz[ah]anthracene (DahA) in the samples collected in Porto. The ratio values of individual PAHs concentrations were used as diagnostic tool to identify the possible origin of PAH in the ambient air of Porto. Based on diagnostic ratios, it may be concluded that automobile traffic emissions, mainly related to diesel vehicles, were the major contribution of PAH levels in the ambient air, although some others contributions, such as coal and wood combustion, were identified.

ATMOSPHERIC IMPACT ASSESSMENT AND MONITORING OF DIOXIN EMISSIONS OF MUNICIPAL SOLID WASTE INCINERATORS IN PORTUGAL

In Portugal two municipal solid waste (MSW) incinerators are under construction in the metropolitan areas of Lisbon and Porto. During the development of the Environmental Impact Assessment (EIA) studies of these units the authors found several limitations and uncertainties associated to the assessment of the environmental impact. Uncertainties were particularly felt on the assessment of the environmental impacts associated with the atmospheric emissions of PCDD and PCDF. At present an External Monitoring Plan is under design.

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.

Numerical Simulation of Meso-Meteorological Circulations in the Lisbon Region

During the last 5 years, the University of Aveiro has directed significant research towards the analysis of regional air quality and problems related to the transport of airborne pollutants over Portugal (Coutinho et al., 1989; Borrego et al., 1991). One of the main conclusions of these studies was the necessity to consider mesoscale atmospheric circulations in studying atmospheric dispersion patterns in Portugal. Mesoscale meteorological models seem to be the most adequate tool to represent those circulations through the mathematical simulation of atmospheric physical processes.

Atmospheric baseline levels of PCDD and PCDF in the region of Oporto

An external monitoring plan (EMP) is being implemented in the region of Oporto, Portugal, to follow the potential effects of a future incinerator of municipal solid waste. Polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/PCDF) were measured during 1998 and the first semester of 1999, prior to the working up of the incineration unit. The baseline levels obtained through this intensive monitoring work are presented and discussed in the present paper.

Intercomparison of two meso-meteorological models applied to the Lisbon region

SummaryIn this paper two mesoscale meteorological models are applied to the Lisbon region. A special concern is directed to the initial conditions and input parameterization in order to assure that equal simulation constraints were imposed to both models. Results obtained for 4 August 1992 (a typical summer day) are compared to meteorological data acquired in three monitoring stations. Both simulations show similar reactions to the mesoscale forcings that occur in the modelling region. The minor differences found between simulation and reality for the meteorological situation can cause major errors in predicting air quality.

Portuguese inventory of dioxins and furans atmospheric emissions

This article presents the results of the most recent estimation of polychlorinated dibenzo-p-dioxins (PCDD) and dibenzofurans (PCDF) atmospheric emissions in Portugal, which has covered the period 2004-2009 and includes 27 emission sources types. The results are compared with previous emissions inventories published for Portugal. The main objective of this work is to provide relevant information about the amounts of the compounds that are released into the atmosphere in Portugal, and identify their major sources and trends. The methodology involved the identification of relevant sources, the collection of information to characterize these sources, the selection of appropriate emission factors and their application to estimate the emissions. Furthermore, several studies conducted in Portugal were considered, namely reports from PCDD/PCDF measurements performed in some industrial facilities. The inventory covered 27 emission sources types. However the results show that only 8 were relevant, i.e. with emission amounts greater than 1 g I-TEQ year(-1). The total emissions of PCDD/PCDF in Portugal reached between 40 and 105 g I-TEQ year(-1), for the period of 2004-2009. The largest emission source and at same time with greater variation is forest fires, with emissions between 3 g I-TEQ year(-1) and 67 g I-TEQ year(-1) in 2008 and 2005, respectively. Excluding the emissions from forest fires, the total emission is more or less constant over the years and around 37 g I-TEQ year(-1).

Comparison of European national legislation efficiency on the reduction of air pollutant emissions.

Abstract Since 1995, the Institute for Environment and Development in Portugal has obtained >300 stack samples from various point sources of Portuguese industries. A coherent database was made with the collected results. The limit values fixed by several European legal documents consulted, Portuguese, Spanish, French, Italian, and Dutch emission legislation, were applied to the Institute for Environment and Development stack sampling inventory (from 1995 to 2000) to evaluate the efficiency of these standards in promoting the control and reduction of atmospheric pollutants emissions, especially regarding nitrogen oxides, sulfur dioxide, and particulate matter. The conclusion was that the original Portuguese legislation was not restrictive enough and not very efficient regarding emissions reduction. In contrast, the Dutch and Italian legislations are quite restrictive but very efficient concerning emission control for the three pollutants analyzed. One of the outcomes of this study was the publication of a new law in Portugal regulating the emissions of atmospheric pollutants. The strategy of this emissions control law follows the conclusions found in this study including the concept of a mass flow threshold and different approaches depending on source dimension.

Introduction of terrain roughness effects into a gaussian dispersion model

Abstract The Gaussian dispersion model is used to predict the concentration field created by a plume during the dispersion phase. Roughness effects are introduced using a differential method for the calculation of the vertical dispersion coefficient. An estimate of terrain roughness is obtained by inspection of topographical land maps. This information is digitalized as proposed by Hosker and stored in topographical files. The present paper stresses the need to consider the effects of terrain roughness on the transport of air pollutants even when described through Gaussian models; the results show an increase of 60% in SO 2 peak concentrations over rough terrain.