Microplastics in indoor deposition samples in university classrooms

Abstract

The pollution caused by microplastics (MPs) is a growing concern on a global scale, especially considering the significant proportion of time that individuals spend indoors. The contamination in question has the potential to directly impact the human population through exposure to indoor dust and air. This research undertook a comprehensive analysis of the indoor deposition of MPs in university classrooms, employing various investigative tools. The present study aimed to comprehensively analyze the physical and chemical properties of MPs found in university classrooms. Analyzing samples under a stereomicroscope, the predominant MPs were identified as fibers of varied colors, mainly attributed to clothing. Sizes of these MPs varied significantly across different classrooms, with a general average size range of 120–2222 µm. The observed morphological changes in MPs, including cracks and grooves, hint at potential degradation into nanosized plastics over time. This observation raises concerns about increased concentrations of nanoplastics in indoor environments. Using µRaman analysis, eleven types of MPs were identified, potentially originating from clothing, shoes, and stationery. The majority of MPs were polyamide 6, polypropylene, and polyamide 12. The scanning electron microscope and energy-dispersive X-ray spectroscopy (SEM–EDX) technique unveiled the elemental composition of the MPs, with carbon, fluorine, and oxygen being dominant. The findings align with past studies but highlight the need to understand MPs' structural components and any possible contaminants. Compared to existing literature, this study adopts a comprehensive methodological approach combining optical microscopy, µRaman, and SEM–EDX, enriching the knowledge on indoor MP deposition and aiding future research directions.