Airborne Microplastic Generation and Transport from 3D Printing Activities in a University Setting

Plastics are everywhere in modern environments, and smaller plastic particles, known as microplastics (MPs, 1 µm-5 mm), have raised increasing concerns regarding indoor air quality and potential human exposure. Given that people spend more than 80% of their time indoors, understanding potential indoor sources and the distribution of MPs is important. Three-dimensional (3D) printing activities have become increasingly common in educational settings and may contribute to indoor MP pollution. However, limited information is available regarding the occurrence, spatial distribution, and physicochemical properties of deposited MPs in and around a university makerspace where filament-extrusion 3D printers and fabric-based activities are routinely used. Deposited particles were collected from multiple locations and characterized using stereomicroscopy and pyrolysis gas chromatography/mass spectrometry (Py-GC/MS). Microscopic analysis quantified particles larger than 10 µm, whereas Py-GC/MS determined mass-based deposition rates for particles larger than 1 µm. MPs were detected throughout the makerspace and in surrounding areas, suggesting potential particle transport beyond the immediate printing area. Methyl methacrylate (MMA) was identified as the predominant pyrolysis product of the black MPs possibly generated by 3D printing activities. These findings provide evidence of MP deposition in a university makerspace and highlight the need for further investigation into indoor MP sources, particle transport, and potential inhalation exposure among individuals engaged in 3D printing and related activities.