Individual Exposure to Microplastics through the Inhalation Route: Comparison of Microplastics in Inhaled Indoor Aerosol and Exhaled Breath Air

Abstract

Human exposure to microplastics (MPs), especially from indoor air, has aroused growing public concern, but very little is known about the assessment of individual MPs inhalation exposure. In this study, a total of 30 volunteers were recruited from Shanghai, China. Both human inhaled indoor aerosol (HIA) and human exhaled breath (HEB) samples were pairwise collected for each participant and analyzed through micro-Raman imaging spectroscopy. MPs were detected in all samples, averaging 43 ± 16 (range of 11–92) items/m3 for HIA and 12 ± 5 (range of 3–28) items/m3 for HEB. Moreover, the dominant components in all samples were small fragment- and fiber-shaped MPs. It is estimated that the daily intake of HIA was roughly 704 ± 254 MPs items, most of which would deposited in the airway with 526 ± 203 MPs items, whereas 178 ± 75 MPs items could be daily discharged via HEB. The actual daily inhalation exposure of MPs could be overestimated by 1.33 times with the HIA-based approach and by 1.40 times for smaller MPs (<10 μm). These results suggest that integration of HIA and HEB should be considered when evaluating individual MPs exposure via respiration.