Fingerprinting and emission rates of particulate organic compounds from typical restaurants in Portugal

Abstract

The aim of this study was a detailed chemical characterisation of the particles released during the preparation of popular Portuguese dishes. PM2.5 samples were collected from the exhaust stacks on the roofs of a university canteen, a charcoal-grilled chicken restaurant and a wood-oven roasted piglet restaurant. The speciation of organic compounds was carried out by gas chromatography-mass spectrometry. The canteen was responsible for the lowest emissions of PM2.5, while emissions from the roasted piglet restaurant were the highest. Naphthalene was quantified as the most abundant aromatic compound in particle emissions from the canteen, while phenanthrene, fluoranthene, pyrene and chrysene were the dominant polycyclic aromatic hydrocarbons in samples from the other establishments. Benzo[a]pyrene equivalent concentrations obtained for the charcoal-grilled chicken and piglet restaurant indicate a dangerous carcinogenic potential to human health. Cholesterol was the prevalent sterol. Its highest values were obtained in particles from the charcoal-grilled chicken restaurant (621 ± 233 μg g-1 PM2.5). Oleic and palmitoleic were the unsaturated fatty acids identified at highest concentrations (from trace levels to 34.4 and to 6.89 mg g-1 PM2.5, respectively). Resin acids, such as dehydroabietic and abietic, were detected in all samples from the wood-oven roasted piglet restaurant. Nicotinamide was the amide detected at highest amount in emissions from the university canteen during the preparation of stews (7.67 mg g-1 PM2.5). Levoglucosan and its isomers were identified in all samples from the roasted piglet restaurant, but only the first monosaccharide anhydride was present in emissions from the university canteen and the charcoal-grilled chicken restaurant. Additionally, emission rates were estimated for the most representative compounds, taking into account the specific activity of each restaurant.