An integrated approach was developed to assess exposure and health-risk from polycyclic aromatic hydrocarbons (PAHs) contained in oil mists in a fastener manufacturing industry. One previously developed model and one new model were adopted for predicting oil mist exposure concentrations emitted from metal work fluid (MWF) and PAHs contained in MWF by using the fastener production rate (Pr) and cumulative fastener production rate (CPr) as predictors, respectively. By applying the annual Pr and CPr records to the above two models, long-term workplace PAH exposure concentrations were predicted. In addition, true exposure data was also collected from the field. The predicted and measured concentrations respectively served as the prior and likelihood distributions in the Bayesian decision analysis (BDA), and the resultant posterior distributions were used to determine the long-term exposure and health-risks posed on workers. Results show that long term exposures to PAHs would result in a 3.1%, 96.7%, and 73.4% chance of exceeding the PEL-TWA (0.2 mg/m³), action level (0.1 mg/m³), and acceptable health risk (10⁻³), respectively. In conclusion, preventive measures should be taken immediately to reduce workers’ PAH exposures.

This study investigates the emissions of polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) from four electric arc furnaces (EAFs) and eight secondary aluminum smelters (secondary ALSs) in Taiwan. The mean PCDD/F International-Toxicity Equivalents (I-TEQ) concentrations in the stack gases of these EAFs and secondary ALSs are 0.28 ng I-TEQ/Nm³ (relative standard deviation [RSD = 100%) and 3.3 ng I-TEQ/Nm³ (RSD = 260%), respectively. The high RSDs, especially for those obtained from secondary ALSs, could be caused by the intrinsic differences in their involved feeding materials, furnace operating conditions, and air pollution control devices. The mean I-TEQ emission factor of PCDD/Fs for EAFs (1.8 μg I-TEQ/tonne-feedstock) is lower than that for secondary ALSs (37 μm g I-TEQ/tonne-feedstock). This result might be because the involved furnace temperatures for secondary ALSs (650–750 °C) are lower than those for EAFs (1600–1700 °C), resulting in the deterioration of the combustion condition, leading to the formation of PCDD/Fs during the industrial process. This study found that the total PCDD/F emissions from EAFs (20 g I-TEQ/yr) and secondary ALSs (18 g I-TEQ/yr) are ∼27, 53, and ∼24, 49 times higher than those from municipal solid waste incinerators (MSWIs; 0.74 g ITEQ/yr) and medical waste incinerators (MWIs; 0.37 g I-TEQ/yr), respectively; while those are 44 and 40% of total PCDD/F emission from sinter plants (45 g I-TEQ/yr), respectively. Considering a more stringent emission limit has been applied to waste incinerators (0.1 ng I-TEQ/Nm³) in Taiwan lately, the results suggest that the control of the emissions from metallurgical processes has become the most important issue for reducing the total PCDD/F emission from industrial sectors to the ambient environment.