Assessment of Workers’ Personal Exposure to Metalworking Fluid Aerosols in an Automotive Parts Manufacturing Facility and Their Health Outcomes

Abstract

This project describes the external exposure levels of metalworking fluid (MWF) in an automobile parts manufacturing factory and analyzes the health effects of MWF on workers so as to provide a scientific basis for optimizing the MWF testing process and evaluating occupational hazards. MWF in the air of the workplace was collected according to the National Institute for Occupational Safety and Health’ analysis method (NIOSH 5524). The mass concentrations of MWF total aerosols and extracted aerosols were determined by weighing and binary or ternary solvent extraction. The quantitative relationship between them was analyzed. The propensity score matching (PSM) method was used to establish the group of subjects. Demographic information, allergic diseases, and clinical laboratory indicators were collected through questionnaire and health examination data, and the health effects of MWF were assessed. Personal sampling of 38 workers in three posts was carried out using a polytetrafluoroethylene (PTFE) filter. The arithmetic means of concentration of total aerosols was 0.43(0.13–1.02) mg/m³, and the extractable aerosols concentration was 0.23(0.05–0.55) mg/m³. There was a significant correlation between total and extractable aerosol levels, and a linear regression equation was established: Y = 0.469X + 0.024 (X is the total aerosols concentration, Y is the extracted aerosols concentration). There was no significant difference in blood routine, liver function, or other biochemical results or indicators between the exposed workers and controls (P > 0.05). The clear linear relationship between concentrations of aerosols indicates that the extracted aerosols level can be reasonably inferred from the total aerosols. Under the circumstances investigated in this project, MWF exposure did not induce significant adverse health effects, as evidenced by the results of occupational medical examination.