Occupational Exposure to Elevated Levels of Inhalable Microplastics in Plastic and Fiber Factory Workers

Micro(nano)plastics enter the human body mainly through inhalable and oral uptake, and the fraction below 20 μm can penetrate biological membranes, accumulate in tissues, and induce cytotoxicity and inflammation. While inhaled indoor air may be a primary source of exposure, concentrations are potentially higher in occupational settings in the plastic and fiber factories. Here, external exposure to inhalable microplastics <100 µm was studied in four industrial workplaces: two non-woven fabric production factories, and two different plastics recycling facilities located in Finland and Spain. Air samples were collected from the worker breathing zone and stationary measurements during various production tasks. For comparison, urban aerosols were assessed in two urban locations in Finland and in France. Inhalable microplastics in the aerosol samples were analyzed using FTIR (Fourier-transform infrared microscopy) imaging and Raman spectroscopy equipped with automated particle analysis and identification algorithms. In addition, total particle number concentration (PNC, 20 – 700 nm) were measured in parallel. PNC varied between the workplaces and tasks, ranging from 2000 to 50000 #/cm³. Aerosols in the plastic recycling factory predominantly contained PS, ABS, PP, PE and EVA particles at elevated concentration, averaging 2000 #/m³ for the inhalable fraction (<100 µm) and 1500 #/m³ for the thoracic and respirable fraction (<10 µm), based on FTIR imaging and Raman analyses. In non-woven fabric manufacturing facilities, inhalable microplastics were dominated by PET fibers, along with PA, PP and PE particles. The median size of inhalable microplastics ranged from 23 – 40 µm in occupational aerosols. Inhalable microplastics in aerosols from the 4 factories ranked among the highest concentrations reported to date, indicating elevated health risks for exposed workers. These novel findings from the validation of sampling and analytical strategies underscore the significance in reducing airborne microplastic emissions and mitigating inhalation exposure, especially in occupational settings.