Industrial influence on atmospheric VOCs and associated health risks in small residential areas near industrial complexes in Ulsan, South Korea

Due to their ubiquitous emissions and associated health risks, atmospheric volatile organic compounds (VOCs) have been extensively studied in urban and industrial areas. However, small residential areas located near industrial facilities have received relatively little attention. Community-scale monitoring of VOCs was conducted using passive air samplers deployed at 7 sites in small residential areas near industrial complexes in Ulsan, South Korea. Among the 59 VOCs analyzed, aromatic compounds such as m,p,o-xylenes (13.6 ± 8.6 µg/m 3 ), toluene (11.7 ± 11.9 µg/m 3 ), and ethylbenzene (5.3 ± 4.0 µg/m 3 ) were predominant. Elevated total VOC concentrations were observed at sites strongly influenced by solvent-related industrial activities. Correlation analysis between measured concentrations and industrial emissions within radii of 0.5, 1, 2, and 3 km indicated that facilities within 3 km were likely major sources of VOCs. Results of diagnostic ratios and principal component analysis indicated that VOCs were primarily influenced by local industrial activities, such as solvent use, fuel combustion, cleaning/degreasing, and petrochemical refining, rather than by regional or long-range atmospheric transport. Among the 23 VOCs evaluated for health risks, naphthalene was the only compound exceeding the US EPA threshold for acute non-cancer risk, primarily affecting the respiratory system. In contrast, cancer and non-cancer risk estimates for chronic exposure remained within acceptable levels. These findings highlight that residents within 3 km of the industrial complexes may be exposed to significant health risks. Therefore, continuous monitoring of VOC levels over various exposure durations (e.g., acute, subchronic, and chronic) is needed, even in small residential areas.