Assessment of the presence and risk associated with volatile and semi-volatile organic compounds in urban areas close to petrochemical parks

This study monitored volatile organic compounds (VOCs) and semi-volatile organic compounds (SVOCs) in urban areas near petrochemical industries using passive sampling. Sampling at six urban sites was conducted throughout 2023, with VOCs sampled every 14 days and SVOCs every 2 months, resulting in a total of 180 samples. VOCs and SVOCs were determined by gas chromatography-mass spectrometry, coupled to thermal desorption in the case of VOCs and after pressurised liquid extraction in the case of SVOCs. Alkanes were the VOCs found at the highest concentrations, with average concentrations between 11.6 μg m^-3 to 30.5 μg m^-3. Particular attention was focused on benzene and 1,3-butadiene due to their carcinogenic nature and their involvement in the local industrial activities. Despite some concentration peaks, the average values of these compounds were always below the limits set by current air quality regulations, with maximum values of 1.70 μg m^-3 for both benzene and 1,3-butadiene. The phthalate ester family stood out among the SVOCs, with average concentrations ranging from 28.1 ng m^-3 to 41.8 ng m^-3. The average values of benzo(a)pyrene were always below the 1 ng m^-3 limit established in air quality regulations for PM₁₀. The risk assessment results showed that the total non-carcinogenic risk ranged from 0.02 to 1.30, with two VOCs, benzene and 1,3-butadiene, contributing the most to the risk. The total carcinogenic risk was between 1.5E-06 and 1.3E-04, with 1,3-butadiene (VOC) being the most significant contributor, accounting for between 18 % and 50 % of the overall risk. Phthalate esters (SVOCs) also made a substantial contribution, representing between 10 % and 39 % of the total risk.