Measurement of trace gases and organic compounds in the smoke plume from a wildfire in Penedono (central Portugal)

Gas and particulate fractions were measured simultaneously from a wildfire in Penedono, central Portugal, which occurred in summer 2009. The total volatile hydrocarbons (THC) and carbon oxides (CO2 and CO) collected in Tedlar bags were measured using automatic analysers with flame ionisation and non-dispersive infrared detectors, respectively. Carbonyls (formaldehyde and acetaldehyde) were sampled from the Tedlar bags in DNHP cartridges and analysed by high-performance liquid chromatography. Fine (PM2.5) and coarse (PM2.5-10) smoke particles were collected sequentially, on pre-fired quartz fibre filters, with a portable high-volume sampler. The detailed speciation of organic compounds in smoke samples was carried out by gas chromatography-mass spectrometry. The organic and elemental carbon content of particulate matter was analysed by a thermal-optical transmission technique. Average emission factors of 1.86 ± 0.80 and 0.063 ± 0.066 g kg−1 (dry basis) were obtained for acetaldehyde and formaldehyde, respectively. The THC, CO, CO2, PM2.5, PM10, OC and EC emission factors (g kg−1 fuel burned, dry basis) were 260 ± 88, 268 ± 92, 1200 ± 172, 37 ± 12.2, 40 ± 12.6, 21 ± 6.7 and 0.44 ± 0.21, respectively. The chromatographically resolved organics included n-alkanes, n-alkenes, n-alkanoic acids, n-di-acids, unsaturated fatty acids, phenolic compounds, ketones, steroids, di- and triterpenoids, PAHs, with retene as the major compound, oxygenated PAH and anhydrosugars.

► OC/EC ratios increased with the intensity of the smouldering phase.
► A strong inverse correlation between acetaldehyde and MCE was obtained.
► Retene was the major PAH present in both fine and coarse particles.
► Among diterpenoids, abietic and pimaric acids were dominant compounds.
► Vanillin(phenolic) and levoglucosan(anhydrosugar) are major constituents of smoke.