Integrated quantitative and semi-quantitative risk assessment of exposure to VOCs in polymer manufacturing: associations with pulmonary function and respiratory symptoms

Occupational exposure to volatile organic compounds (VOCs) in the petrochemical industry poses significant health risks, including carcinogenic and respiratory effects. This study compares the findings of quantitative risk assessment methods (USEPA) with semi-quantitative methods (Singaporean) while evaluating the impact of these chemicals on pulmonary function. This descriptive-analytical, cross-sectional study was conducted from 2024 to 2025 at an acrylonitrile-butadiene-styrene (ABS) production facility in Iran. A total of 240 male workers (120 exposed, 120 non-exposed controls) were selected with 480 personal air samples. Air sampling was performed following NIOSH methods (1501, 1604, 1024). Pulmonary function was assessed via spirometry, and respiratory symptoms were evaluated with the American Thoracic Society questionnaire. Health risks were quantified using the EPA’s Lifetime Cancer Risk (LCR) and Hazard Quotient (HQ) for quantitative analysis and the Singaporean semi-quantitative method. The mean concentrations of benzene, ethylbenzene, acrylonitrile, 1,3-butadiene, and styrene were measured and estimated as 0.157 ± 0.08, 22.49 ± 10.68, 0.33 ± 0.157, 0.22 ± 0.167, and 6.26 ± 2.66 mg.m − 3 , respectively. The results showed that Exposed workers showed reduced pulmonary function and Respiratory symptoms were significantly higher in the exposed group. The risk assessment revealed elevated and definite carcinogenic risks for all chemicals, with LCR values ranging from 2.00 × 10⁻³ (styrene) to 1.26 × 10⁻¹ (acrylonitrile). Risk Ratio (RR) indicated “Probable” risk for most compounds (RR: 2.23–3.16), except styrene (“Possible”, RR: 1.73). Non-carcinogenic risk (HQ) was “High” for all substances except styrene (“Low”), with HQ values ranging from 0.708 to 18.67. Both EPA and Singaporean methods identified significant carcinogenic and non-carcinogenic risks from benzene, acrylonitrile, and 1,3-butadiene exposure. Occupational VOCs exposure was associated with impaired pulmonary function and increased respiratory symptoms, necessitating enhanced control measures.