Contribution of individual sources of volatile organic compounds to their cancer and non-cancer risks in the multi-industrial city of Ulsan, South Korea

Previous studies have investigated the major sources and health risks associated with atmospheric volatile organic compounds (VOCs). However, the spatial variability of the impact of their emission sources on health risks has rarely been studied. In this study, passive air sampling of VOCs was conducted at 24 sites in Ulsan, the largest industrial city in South Korea. Toluene exhibited the highest time-averaged concentration (6.37 µg/m³), followed by m,p,o-xylenes (4.69 µg/m³), ethyl acetate (3.26 µg/m³), and ethylbenzene (2.70 µg/m³). Higher concentrations of total (Σ₅₉) VOCs and BTEX (benzene, toluene, ethylbenzene, and m,p,o-xylenes) were observed near industrial complexes. The mean cumulative (Σ₁₁) cancer risk was 9.1E-6, with the highest contribution from benzene (4.7E-6), while the mean cumulative (Σ₁₇) non-cancer risk was 2.6E-1, primarily driven by naphthalene (1.7E-1), suggesting the importance of carcinogenic VOCs. Five major sources were identified using the positive matrix factorization model, revealing the dominance of industrial activities. Both cancer and non-cancer risks were elevated in the petrochemical industrial complex, which is located close to densely populated areas. Consequently, prioritized management of VOC exposure to workers and residents is necessary for the petrochemical industrial complex and nearby residential areas.