Personal Exposure to Sulfuric Acid in the Electroplating Industry: Development and Validation of a Predictive Model

This study aimed to measure personal exposure to sulfuric acid in the electroplating industry to establish a predictive model and test its validation. We collected indoor air parameters and related information from four electroplating plants. Silica gel sorbents were used to collect air samples using high-performance ion chromatography. We collected air samples from three plants (i.e., Plant B, Plant C, and Plant D) and applied multiple linear regressions to build a predictive model. Eight samples collected from the fourth plant (i.e., Plant A) were used to validate the model. A total of 41 samples were collected with a mean of 25.0 ± 9.8 μg/m³ (range 12.1-51.7 μg/m³) in this study, including Plant A (8 samples, 17.5 ± 2.8 μg/m³, 13.0-22.0 μg/m³), Plant B (11 samples, 36.5 ± 9.7 μg/m³, 23.1-51.7 μg/m³), Plant C (11 samples, 16.4 ± 1.7 μg/m³, 12.1-17.8 μg/m³), and Plant D (11 samples, 27.4 ± 1.7 μg/m³, 24.1-29.9 μg/m³). Plant B was significantly higher in sulfuric acid than the other plants. Workers from the electroplating process plants were exposed to sulfuric acid at 29.0 ± 11.5 μg/m³. The predictive model for personal exposure to sulfuric acid fit the data well (r² = 0.853; adjusted r² = 0.837) and had an accuracy of 5.52 μg/m³ (bias ± precision; 4.98 ± 2.38 μg/m³), validated by the personal sampling of the fourth plant. This study observed that sulfuric acid exposure was lower than the permissible exposure level of 1000 μg/m³ in Taiwan and the United States, and only two samples were lower than the European Union standard of 50 μg/m³. The developed model can be applied in epidemiological studies to predict personal exposure to sulfuric acid in plants using electroplating.