Airborne microplastic contamination across diverse university indoor environments: A comprehensive ambient analysis

Microplastics (MPs) have become a growing concern in the context of environmental pollution, with an increasing focus on their presence in indoor environments, including university facilities. This study investigates the presence and characteristics of MPs in different university indoor environments. Initial examination of indoor ambient MPs involved physical characterization through optical microscopy, focusing on classifying MPs by shape and color. Various types of MPs, including fibers, fragments, pellets, foams, films, and lines, were identified, with the most common colors being black, red, blue, and brown. Fragments were the predominant type of MPs found, although accurately quantifying their numbers proved challenging due to the dense sample content. These MPs displayed rough and irregular margins suggestive of abrasion. Subsequent chemical and elemental characterization was conducted using micro-Raman and SEM-EDX, revealing the presence of 25 different types of MPs, including PA 66, PTFE, PP, HDPE, and PE. The study indicates that university inhabitants are exposed to airborne MPs (≥ 2.5–336.89 μm) at inhalation rates of 13.88–18.51 MPs/m³ and 180–240 MPs daily. These MPs exhibited significant variations in size, and their distribution varied among the different indoor environments studied. SEM-EDX analysis revealed common elements in the identified MPs, with C, O, F, Na, Cl, Al, Si, and others consistently detected. This research is the first to comprehensively analyze MPs in nine different indoor university environments using active sampling. Identifying and reducing MP contamination in these facilities might stimulate more awareness, promote extensive scientific investigation, and facilitate the development of informed policies.