VOC emissions of smouldering combustion from Mediterranean wildfires in central Portugal

Abstract

Emissions of trace gases and C5–C10 volatile organic compounds (VOCs) from Mediterranean wildfires occurring in Portugal in summer 2010 were studied. Fire smoke was collected in Tedlar bags and analysed for CO, CO2, total hydrocarbons (THC) and VOCs. The CO, CO2 and THC emission factors (EFs) were 206 ± 79, 1377 ± 142 and 8.1 ± 9 g kg−1 biomass burned (dry basis), respectively. VOC emissions from Mediterranean wildfires were reported for the first time. Aromatic hydrocarbons were major components of the identified VOC emissions. Among them, benzene and toluene were dominant compounds with EFs averaging 0.747 ± 0.303 and 0.567 ± 0.422 g kg−1 biomass burned (dry basis), respectively. Considerable amounts of oxygenated organic volatile compounds (OVOCs) and isoprenoids were detected. 2-Furaldehyde and hexanal were the most abundant measured OVOCs with EFs of 0.337 ± 0.259 and 0.088 ± 0.039 g kg−1 biomass burned (dry basis), respectively. The isoprenoid emissions were dominated by isoprene (EF = 0.207 ± 0.195 g kg−1 dry biomass burned) and α-pinene (EF = 0.112 ± 0.093 g kg−1 dry biomass burned). Emission data obtained in this work are useful for validating and improving emission inventories, as well for carrying out modelling studies to assess the effects of vegetation fires on air pollution and tropospheric chemistry.