Characterization and quantification of microplastics in indoor environments

Microplastics (MPs) have gradually attracted attention; however, people have paid limited attention to the existence of airborne microplastics, especially in indoor environments. In this study, we tracked microplastic deposition in offices, laboratories, dining halls, and dormitories. Results showed that the average microplastic abundance in the dormitory was the highest (14088.05 pcs/m3), followed by in the office (13097.13 pcs/m3), laboratory (7512.55 pcs/m3) and dining hall (4308.26 pcs/m3). The microplastics deposited at indoor environment were mostly dark, elongated and solid. The average particle size of the microplastics sampled at the four sampling points was 66.15 μm, but the size of the microplastics in the laboratory environment was smaller and more harmful. Airflow tests using air conditioners showed that turbulence increases the resuspension of microplastics. Our results also show that the frequency of human activities is one of the main factors leading to changes in the content of microplastics in indoor air, and turbulence caused by airflow will lead to the migration of microplastics in the indoor environment. In conclusion, indoor environments are prone to high microplastic concentration, which may pose certain potential risks to human health.