Air monitoring with passive samplers for volatile organic compounds in atmospheres close to petrochemical industrial areas. The case study of Tarragona (2019-2021)

This study reports a three-year monitoring campaign of 62 volatile organic compounds (VOCs) of increasing concern in urban atmospheres near petrochemical industrial areas. A total of 770 air samples were taken during the sampling campaigns conducted monthly between January 2019 and December 2021. The analytical method applied involved a 14-day passive sampling in Carbopack X tubes followed by thermal desorption-gas chromatography-mass spectrometry (TD-GC-MS). To gain insight into the correlations between VOCs, multivariate data analysis was used to assess the similarities and differences between datasets. Special attention was paid to benzene, 1,3-butadiene and 1,2-dichloroethane, because they are carcinogenic and are produced, handled and stored in the petrochemical industrial areas studied. The compounds found in the highest concentrations were alkanes, which were 21-66% of the total. Aromatic hydrocarbons and solvents were also detected at all the sampling sites, with BTEX and ethanol as the most prevalent compounds. Various concentration peaks of up to 4.8 mu g m(-3) for benzene and up to 4.0 mu g m(-3) for 1,3-butadiene were detected during the monitoring campaigns performed. Nevertheless, the average concentrations of these two compounds were always below the values set in the current air quality regulations, with maximum values of 1.3 mu g m(-3) for benzene and 1.5 mu g m(-3) for 1,3-butadiene near the North industrial park of Tarragona. Multivariate analysis results revealed four different patterns at the reference sites and discriminated between the sampling sites close to the petrochemical areas evaluated. The autumn-winter months, with thermal inversion phenomena and prevailing north and north-westerly winds, were the ones with the highest concentration levels of VOCs.