Forest fires and air quality under a climate change scenari

Forest fire activity and air quality under a changing climate are considered one of the main threats to sustainable development. The interaction between the climate, the forest fire activity and the air quality over Portugal is the main purpose of this study.;The relationship between the weather, the fire weather risk and the forest fire activity has been assessed for twelve districts over Portugal. Statistical significant correlations have been established among the analysed variables indicating the weather as the most important natural factor influencing forest fires in Portugal. In order to better assess the role of the regional scale atmospheric conditions in fire activity, the typical structural evolution of the atmospheric field patterns in a wildfire event was investigated by lagged analysis. The analysis pointed out that in the pre-phase of a forest fire event heated air is transported from the Iberian Peninsulafs centre towards Portugal. Having in mind the important role of the atmospheric conditions on fire activity statistics over Portugal, the fire weather under the IPCC SRES A2 scenario was assessed for two spatial resolutions, 12 km and 25 km. A substantial increase on the future fire weather risk over Portugal especially in the inner districts of the North and Centre is expected.;Taking into account that the weather explains the majority of the forest fire activity in Portugal and based on the fire weather projections under future climate it was possible to forecast future area burned and number of forest fires. The projections showed a substantial increase on the area burned namely in Braganca and Porto districts. By the end of the XXI century, Portugal may face increases of approximately 500 % and 300 % for area burned and number of fires, respectively, comparatively to the 80s.;Based on the future area burned projections it was possible to estimate future fire emissions and to evaluate their impact on air quality. The MM5/CHIMERE air quality modelling system was applied to the reference and to the future climate scenarios. The projected impacts pointed that climate change alone enhances the ozone levels in the atmosphere of up to 20 mug m-3. When forest fire emissions are also considered the ozone levels decrease in the vicinity of the forest fires but increase downwind of their locations. The particulate matter in the atmosphere will increase but decreases may also be detected. This study constitutes an innovative scientific tool that helps to fundament strategies and policies to face and mitigate future climate change impacts on forest fire activity and air quality.