Vera Martins

Wildland Smoke Exposure Values and Exhaled Breath Indicators in Firefighters

Smoke from forest fires contains significant amounts of gaseous and particulate pollutants. Firefighters exposed to wildland fire smoke can suffer from several acute and chronic adverse health effects. Consequently, exposure data are of vital importance for the establishment of cause/effect relationships between exposure to smoke and firefighter health effects. The aims of this study were to (1) characterize the relationship between wildland smoke exposure and medical parameters and (2) identify health effects pertinent to wildland forest fire smoke exposure. In this study, firefighter exposure levels of carbon monoxide (CO), nitrogen dioxide (NO2), and volatile organic compounds (VOC) were measured in wildfires during three fire seasons in Portugal. Personal monitoring devices were used to measure exposure. Firefighters were also tested for exhaled nitric oxide (eNO) and CO before and after their firefighting activities. Data indicated that exposure levels during firefighting activities were beyond limits recommended by the Occupational Exposure Standard (OES) values. Medical tests conducted on the firefighters also indicated a considerable effect on measured medical parameters, with a significant increase in CO and decrease in NO in exhaled air of majority of the firefighters.

Impact of forest fires on particulate matter and ozone levels during the 2003, 2004 and 2005 fire seasons in Portugal.

The main purpose of this work is to estimate the impact of forest fires on air pollution applying the LOTOS-EUROS air quality modeling system in Portugal for three consecutive years, 2003-2005. Forest fire emissions have been included in the modeling system through the development of a numerical module, which takes into account the most suitable parameters for Portuguese forest fire characteristics and the burnt area by large forest fires. To better evaluate the influence of forest fires on air quality the LOTOS-EUROS system has been applied with and without forest fire emissions. Hourly concentration results have been compared to measure data at several monitoring locations with better modeling quality parameters when forest fire emissions were considered. Moreover, hourly estimates, with and without fire emissions, can reach differences in the order of 20%, showing the importance and the influence of this type of emissions on air quality.

Forest Fires Impact on Air Quality over Portugal

The main purpose of this work is to estimate the air pollution effects of 2003 forest fires through the application of two air quality modelling systems (CHIMERE and LOTOS-EUROS) over Portugal and its intercomparison. Forest fire emissions were estimated based on specific southern European emissions factors, on type of vegetation and area burned, and incorporated in the emission input data of both modelling systems. Results showed a significant performance improvement when forest fires are taken into account. PM10 and O3 values can reach differences in the order of 30%, showing the importance and the influence of this type of emissions from local to regional air quality. The different results of the two models may give an indication of the uncertainty associated by using different models to investigate the impact of forest fires. Historical datasets of area burned, number of fires and air quality data were evaluated from 1995 to 2005 aiming to investigate a potential relationship between forest fire activity and air pollutants concentrations. The obtained results point to statistically significant correlations between fire activity in Portugal and PM10 and O3 levels in the atmosphere.

Ensemble Techniques to Improve Air Quality Assessment: Focus on O3 and PM

Five air quality models were applied over Portugal for July 2006 with an ensemble purpose. These models were used, with their own meteorology, parameterizations, boundary conditions and chemical mechanisms, but with the same emission data. The validation of the individual models and its ensemble for ozone (O3) and particulate matter was performed using monitoring data from 22 background stations over Portugal. After removing the bias from each model, different ensemble techniques were applied and compared. Besides the median, several weighted ensemble approaches were tested and intercompared: static (SLR) and dynamic (DLR) multiple linear regressions (using less-square optimization method) and the Bayesian Model Averaging (BMA) methodology. The goal of the comparison is to estimate to what extent the ensemble analysis is an improvement with respect to the single model results. The obtained results revealed that no one of the 4 tested ensembles clearly outperforms the others on the basis of statistical parameters and probabilistic analysis (reliability and resolution properties). Nevertheless, statistical results have shown that the application of the weights slightly improves ensemble performance when compared to those obtained from the median ensemble. The same statistical analysis together with the probabilistic measures demonstrates that the SLR and BMA methods are the best performers amongst the assessed methodologies.

Forest Fire Emissions and Air Pollution in Southern Europe

Forest fires are one of the most impressive forces of nature. Their disturbing effects include, among many others, the emission of large amounts of gases and particles to the atmosphere, with significant impacts on air quality and human health. The work here presented summarizes the current state of research in what respects to the atmospheric emissions of forest fires and their relationship with air quality. An overview of the current emission models is presented, including a collection of emission factors suitable for application to southern European forest fires. Emission measurement techniques, as well as air quality measurements, are presented under the framework of Lousa 2004 field fire experiments. The extreme fire events that took place in the summer of 2003 in southern Europe are illustrated with two case studies for Portugal. Two air quality modelling systems were applied, LOTOS-EUROS and AIRFIRE, revealing the severe degradation of air quality due to forest fires, namely in what concerns particulate matter and ozone levels. The need to integrate air quality policies in forest management in order to reduce the number of air pollution episodes besides the risk of unwanted fires is a clear outcome of this chapter.

Area burned in Portugal over recent decades: an extreme value analysis

Forest fires are a major concern in Europe, particularly in Portugal where large forest fires are responsible for negative environmental, social and economic effects. In this work, a long time series of daily area burned in 18 Portuguese districts (north, coastal areas and inner–south) from 1980 to 2010 are analysed to characterise extreme area burned and regional variability. The analysis combines the peak-over-threshold method and classification techniques to cluster the time series on the basis either of their corresponding tail indices or their predictive distributions for 5- and 15-year return values, that is, the level that is exceeded on average once every 5 or 15 years. As previously reported in other wildfire studies, the results show that the distributions of area burned (1980–2010) are heavy tailed for all Portuguese districts, with considerable density in the tail, indicating a non-negligible probability of occurrence of days with very large area burned. Moreover, clustering based on tail indices identified three distinct groups with spatial pattern closely related to the percentage of shrub cover within each district. Finally, clustering based on return values shows that the largest return levels of area burned are expected to occur in districts located in the centre and south of Portugal.

Numerical modelling of the impact of wildland-urban interface fires on Coimbra air quality.

Forest fires are a major emission source of pollutants to the atmosphere with several adverse impacts on human health and ecosystems either at local, regional or global scales. Entire populations can be exposed to hazardous concentrations of toxins, especially when fire occurs in the vicinity of cities, as recently drawn by large wildfires in Southeast Asia, Australia, South America or Russia, but also Southern Europe, namely in Portugal. Nowadays there is a growing concern about the increase in both the frequency and the severity of forest fires spreading in the urban wildland interface (WUI) as a consequence of the escalation of urban development among or adjacent to wildlands. The main purpose of this paper is to estimate the impact of wildland forest fires on the air quality of a city in Portugal. Aiming to take into account the effect of a larger atmospheric scale in the very local urban one, a multi-scale approach was adopted, which implied the link between a chemistry-transport mesoscale model (LOTOS-EUROS) and a microscale computational fluid dynamics (CFD) model. Forest fire emissions were estimated based on specific southern European emission factors, type of vegetation, area burned and fire behaviour, and were incorporated in the emission input data of the numerical modelling system. Results confirm the strong impact of forest fires on the urban air pollution levels. Statistical indicators were used to validate the modelling application through the comparison of results to measured air quality data. This modelling approach has got very good performance skills showing the possibility of applying this kind of system to analyse the relation between forest fires and urban air pollution.