Occurrence Characteristics and Estimated Inhaled Intake of Airborne Microplastics Across Campus Micro-Environments: A Two-Participant Pilot Study

Airborne microplastics (AMPs) are recognized as emerging pollutants, exerting widespread impacts on both the ecological environment and human health. While existing research has predominantly focused on the occurrence characteristics, studies addressing human exposure patterns remain limited. In this study, a typical campus in Zhenjiang, a city in East China, was selected as the research site. By integrating students’ daily activity trajectories, active sampling methods were employed to estimate 24 h inhaled AMP intake, alongside simultaneous monitoring of environmental parameters such as temperature, relative humidity, and air pressure. Each participant used one filter throughout the 24 h monitoring period. The results revealed average AMPs abundances of 0.49 items/m3 and 0.82 items/m3 during the sampling period, with fibers being the most prevalent morphology (63%), followed by fragments (27%) and pellets (10%). μ-Raman spectroscopy analysis identified polypropylene (PP), polystyrene (PS), and polymethyl methacrylate (PMMA) as the primary polymer types, constituting 70% of the total. PP and PS were the dominant polymer types in the two trajectory-integrated samples; however, polymer identity alone did not permit definitive source attribution. A large proportion of the μ-Raman-identified particles fell within the 1–5 μm range; however, this fine-size fraction should be interpreted cautiously because representative spectra and particle-specific spectral matching records were not available for further verification. Based on the activity trajectories, the estimated daily inhalation intake of AMPs by students in campus micro-environments was approximately 91.5 items/day per person. PMMA was identified in Sample A, whose trajectory included the volleyball gym; however, the integrated sampling design did not permit location-specific source attribution or comparison of individual activity locations. This study provides preliminary information on AMP occurrence characteristics and estimated inhaled intake. This study is a preliminary pilot study, with 24 h personal exposure monitoring conducted on only two participants. We will increase the sample size in follow-up experiments to draw broader conclusions regarding airborne microplastic exposure across the campus.