Keywords: volatile organic compounds, VOC, cold trap injection, gas chromatography, flame ionisation detection, FID, seasonal variation, diurnal cycles, principal component analysis, PCA, Portugal, atmospheric hydrocarbons, air pollution, measurement, monitoring
Analysis and interpretation of the monitoring data for C2?C11 hydrocarbons in the atmosphere of a rural Portuguese site
This paper focuses the application of a measurement technique for determining atmospheric C2?C6 hydrocarbons after canister sampling and analysis by gas chromatography/flame ionisation detection (GC/FID), as well of an adsorption-sampling technique for C6?C11 compounds and GC/FID analysis after thermal desorption and cryogenic concentration. Tens of samples collected at Giesta, a rural area located 20 km to the SE of the coastal Portuguese city of Aveiro, were analysed. The characterisation of C2 C11 hydrocarbons is presented, considering seasonal variations, diurnal cycles, the influence of air masses and different photochemical conditions. Ratios between hydrocarbons and principal components analysis were applied to differentiate between biogenic and anthropogenic sources.