Ambient levels and health risk assessment of BTEX and inorganic pollutants in the vicinity of mega-industrial area

Benzene, toluene, ethylbenzene, and xylenes (BTEX) are categorized as hazardous air pollutants (HAPs) due to their role in ground-level ozone formation and cancer and non-cancer risk in humans. This study aimed to determine BTEX concentration and their seasonal variations, spatial mapping, and ozone formation potential (OFP) in four locations and assess health risks in workers and populations living near Southern Iran's largest petrochemical complexes and gas refineries. The analytical method was based on NIOSH method 1501. Ambient air sampling was collected by activated charcoal tubes and was analyzed using a gas chromatograph with a flame ionization detector. Results indicated that the ƩBTEX concentrations ranged from 2.3 ± 0.9 to 61.7± 9.8 μg m−3. The highest concentrations of benzene, toluene, ethylbenzene, p-xylene, m-xylene, and o-xylene were found in the petrochemical zone at the wastewater treatment unit with 27.8, 14.2, 12.7, 6.7, 6.9, and 6.2 μg m-3, respectively. The high levels of BTEX were detected during the winter season. The m-xylene was the largest contributor to the OFP at the industrial sampling points, with 34.5 and 36.7 μg m-3, respectively. Toluene has the maximum contribution to ozone formation in the residential areas and Nayband National Park with 24.2 and 5.6 μg m-3, respectively. The cancer risk for benzene in all sampling points at the industrial areas was 1.0E-06, which is higher than the limits recommended by the US EPA.