2.3 FOREST FIRE EMISSIONS UNDER CLIMATE CHANGE: IMPACTS ON AIR QUALITY Anabela Carvalho*1, Alexandra Monteiro 1, Mike Flannigan 2, Silvina Solman 3, Ana I. Miranda 1 and Carlos Borrego 1 1CESAM & Department of Environment and Planning, University of Aveiro, Aveiro, Portugal 2Great Lakes Forestry Centre, Sault Ste Marie, Canada 3CIMA, Buenos Aires, Argentina increases of about 5 ppb by 2030 and 20 ppb 1 INTRODUCTION by 2100 (Prather et al ., 2003). Under the Each summer, wildland fires burn a SRES-A2 scenario, Szopa et al . (2006) considerable area of the south European estimated that by 2030, O 3 July levels may landscape. Most of the fires take place in the increase up to 5 ppb over Europe. Based on Mediterranean region, which suffers over 95% the ensemble mean of 26 global atmospheric of the forest fire damage. Portugal is one of chemistry-transport models (CTMs), Dentener the European countries most affected by forest et al . (2006) predict that by 2030, global fires, mainly during the summer season, which surface ozone may increase globally by is characterized by a hot and dry weather (EC, 4.3 ±2.2 ppb for the IPCC SRES A2 scenario. 2005). The same study points out that the more Smoke is considered as one of the several polluting SRES A2 scenario would compromise disturbing effects of forest fires. Its impacts on attainment of any existing air quality standard air quality and human health can be significant in most industrialized parts of the world by because large amounts of pollutants are 2030. emitted into the atmosphere. Smoke from In a changing climatic scenario forest fire forest fires includes significant amounts of activity is predicted to increase in the Mediterranean region (Moreno et al ., 2005; carbon dioxide (CO 2), carbon monoxide (CO), Carvalho et al ., 2007b) leading to an increase methane (CH 4), nitrogen oxides (NO x), of pollutants release to the atmosphere ammonia (NH 3), particulate matter (PM), non- methane volatile organic compounds (VOCs), (Carvalho et al ., 2007a). The interaction between climate change, forest fires, area sulphur dioxide (SO 2) and other chemical species (Miranda et al ., 2005a). The effects of burned, air pollutants emissions and the these emissions are felt at different levels: associated influence on air quality is still poorly from the contribution to the greenhouse effect studied. In this sense, this work intends to to the occurrence of local atmospheric evaluate the effect of a changing climate and pollution episodes (Miranda et al ., 1994; future forest fire emissions on the air quality Borrego et al ., 1999; Simmonds et al ., 2005). over Portugal. The air pollution episodes related to forest fire activity have been addressed by several studies worldwide (e.g . Hodzic et al ., 2007). In 2 DATA and METHODS a changing climatic scenario forest fires may become an even larger source of air pollutants 2.1 Statistical analysis to the atmosphere (Amiro et al ., 2001; O3 and particles with mean diameter lesser Carvalho et al ., 2007a). than 10 µm (PM 10 ) concentration values were The impact of climate change due to measured at the air quality network stations anthropogenic emissions on air quality is one between 1995 and 2005, and the area burned of the main threats to the sustainable and number of fires, by district, were development particularly in what concerns determined for the same period. We focused human health and environmental resources. on three different periods: annual, June to Several studies have been addressing this September, and August. The daily area burned issue worldwide. Hauglustaine et al . (2005) and the daily number of fires were correlated suggest that ozone (O 3) could increase during with the daily maximum O3 concentration and st the 21 century as a direct consequence of daily average PM 10 , registered in each air enhanced anthropogenic emissions of O 3 quality station, by district. Figure 1 presents the precursors like NO x, CO and VOCs. An air quality stations used in this analysis. evaluation of the high-emissions IPCC SRES A2 (Nakicenovic et al ., 2000) emissions scenario showed global mean surface O 3 * Corresponding author : Anabela Carvalho, Universidade de Aveiro, Dep. de Ambiente e Ordenamento, Campus Universitário, 3810-193, Aveiro, Portugal; e-mail : [email protected] 9°W 8°W 7°W Air quality data were available at 12 42°N 42°N Viana districts in Portugal (Aveiro, Braga, Coimbra, do Castelo Castelo Branco, Évora, Faro, Leiria, Lisboa, ! Bragança Braga Vila Real ! ! ! Porto, Santarém, Setúbal, Vila Real). For each ! ! ! ! Porto district several air quality stations were 41°N 41°N ! considered except in Vila Real, Coimbra, Leiria, Viseu Aveiro ! Guarda Castelo Branco, Santarém and Évora (Figure 1). Only the background stations were included ! Coimbra ! 40°N 40°N in the analysis. ! Castelo Branco Figure 2 presents the data availability Leiria Santarém between 1995 and 2005 for O 3 and PM 10 by ! Portalegre station. Considering the monitoring station Lisboa 39°N 39°N acquisition efficiency is 75% for O (DL ! 3 ! ! ! ! ! ! ! Évora ! 320/2003) and 85% for PM 10 (EC, 2002), the !! data availability is quite different among all the Setúbal ! analysed background stations. Some of the 38°N 38°N Beja stations, namely in Faro district, only have one 025 50 100 km year of data. ! Faro ! ! ! 37°N 37°N 9°W 8°W 7°W Figure 1. Air quality stations location (dot points) and Portuguese districts identification. a) b) Figure 2. Data availability for O3 a) and PM 10 b), by station, for the 1995-2005 period. In order to assess the pollutants’ SRES A2 scenario. Here we describe a brief concentrations measured during the analysed summary of the main results relevant for this period a brief analysis was conducted. The work. median of the O 3 maximum concentrations Daily climatic data were collected from the ranged between 75 and 100 µg.m -3 in all regional climate model HIRHAM (Christensen districts, except in Vila Real (Lamas de Olo et al ., 1996) at two spatial resolutions, 12 km station) where reaches 120 µg.m -3 (Figure 3). and 25 km, from the Prediction of Regional The maximum value is also attained at this scenarios and Uncertainties for Defining measuring station 361 µg.m -3, in 2005. EuropeaN Climate change risks and Effects – Concerning PM 10 , during this period the PRUDENCE – project (PRUDENCE, 2005), maximum value was attained at Leiria district considering the SRES A2 scenario. The (Ervedeira station), 360 µg.m -3 (Figure 3) and HIRHAM 12 km and 25 km climate scenarios the percentile 75 was always below 50 µg.m -3, were used to assess the fire weather under a except in Aveiro district. 2 x CO 2 climate and to estimate future area burned in Portugal. Historical relationships 400 between the area burned, the number of fires, Median 25%-75% Min-Max 350 the Canadian Fire Weather Index (FWI) 300 System components (Van Wagner, 1987) and ) -3 the weather were established for the 1980- 250 2004 period. These relationships were applied 200 under a climate change scenario in order to 150 estimate future area burned, by district, in daily maximum (µg.m maximum daily 3 O Portugal. At a 0.05 significance level there is 100 no statistical significant difference between the 50 area burned projections at 12 km and 25 km 0 resolution. Table 1 presents the observed annual area burned for the 1980-1990 period Faro Porto Leiria Evora Braga Aveiro Lisboa Setubal Coimbra Santarem Vila_Real along with the predicted area burned for each Castelo_Branco district and for all analyzed districts for the 2 x a) CO 2 scenario. The 1980-1990 period was 400 used as the reference climate validation and Median 25%-75% Min-Max 350 was also considered in the area burned analysis. As there was not any statistically 300 ) -3 significant difference between HIRHAM 2 x 250 CO 2/1 x CO 2 ratios at 12 km and 25 km, the 200 area burned projection was based on the average ratios obtained from both simulations. 150 daily average (µg.m average daily 10 Table 1 presents a strong increase of area PM 100 burned, particularly in Bragança and Porto 50 districts showing increases of 643% and 0 606%, respectively. All districts exhibit increases in area burned above 250% except Faro Porto Leiria Evora Braga Aveiro Lisboa Setubal Coimbra Santarem Lisboa (238%) district. In the 1980s Coimbra Vila_Real district already represented the higher Castelo_Branco percentage of contribution (20.9%) to the b) overall area burned in the 11 districts. In a 2 x Figure 3. O3 daily maximum concentration -3 CO 2 scenario Coimbra also presents the (µg.m ) a) and PM 10 average concentration -3 highest contribution to the total area burned (µg.m ) b), by district, between 1995 and 2005 and, in addition, this contribution also increases (23.2%). Almost all districts face an SAS program version 9.1.3 (SAS, 2004) increase in the area burned percentage was used to estimate the Spearman contributions to the total area burned except correlation coefficients between the pollutants’ the districts of Lisboa and Santarém and the concentrations and the area burned and Southern region formed by Portalegre, Évora number of fires. All results are statistically and Beja. Vila Real district shows a decrease significant at a 0.05 significance level. in its contribution percentage. The results seem to point to a North/South dichotomy with 2.2 Area burned in a 2xCO 2 scenario higher increases in the North and Central part Carvalho et al . (2007b) present the area and lesser in the South. burned projections for Portugal for the IPCC Table 1. Annual area burned (ha) by district, observed in 1980-1990 period and predicted for the 2 x CO2 climate, considering the average 2 x CO 2 /1 x CO 2 ratio between HIRHAM 12 km and HIRHAM 25 km simulations.