Characterization of microplastics in indoor and ambient air in northern New Jersey

Airborne microplastics (MPs) could have negative impacts on human health and pollute water, soil, and sediment. This study explored the distributions, compositions, and morphology of airborne microplastics in the indoor and ambient air in New Jersey, United States. Microplastic fibers, films, and fragments of Polystyrene (PS), Polyethylene terephthalate (PET), Polyethyelene (PE), Polyvinyl chloride (PVC) and Polypropylene (PP) were identified in office, hallway, classroom, and single-family house in this study. The deposition rates of synthetic fibers with length from 35 mu m to 1000 mu m were highest in the single-family house ((1.96 +/- 1.09) x 10(4) fibers/ m(2)/day) and lowest in the classroom ((6.20 +/- 0.57) x 10(3) fibers/m(2)/day), suggesting that residential houses are a major source of microplastic fibers. However, for film-like plastics with surface areas ranging from 200 mu m(2) to 5000 mu m(2), a high deposition rate of (8.13 +/- 2.17) x 10(3) films/m(2)/day was observed in the classroom, whereas the lowest deposition rate of (4.45 +/- 0.27) x 10(3) films/m2/day was found in the hallway, probably because plastic films such as PE are intensively used in the classroom environments. The deposition rate of microplastics in the ambient air acquired on a building roof was only about 2-8% of the indoor deposition rates. The microplastics with similar textures but different sizes were identified in both total atmospheric deposition and particulate samples (PM2.5 and PM10), suggesting degradation from microplastics to nanoplastics. The main microplastics found in indoor air samples were PE fragments or fibers, different from those in the outdoor ambient air that were dominated by PVC fragments. These results unravel the properties of airborne microplastics in urban environments that are important to understanding their fate, transport, and potential health risks.

Automated summary

This study investigated the presence and characteristics of airborne microplastics in indoor and ambient air in New Jersey, United States. It found that residential houses are a major source of microplastic fibers, while classrooms have high deposition rates due to the use of plastic films.