Falling indoor microplastics and their potential exposure in school classroom: case study in eastern Indonesia

Microplastics (MPs) are tiny particles found in our environment, including in the indoor environment. This study aims to characterize the microplastic fallout and its potential exposure in the school classroom in Makassar, Indonesia. Sampling was conducted in 6 schools in Makassar over 24 h, including both weekdays and weekends. MPs were identified by passive sampling of dust deposits, which were then observed visually using a portable microscope. The size of the microplastic was measured using the image-J application. The results showed that indoor microplastic abundance was higher on weekdays than on weekends, with the highest concentration at School 6 at 10786 MP/m2/day. The most dominant types of microplastics are fragments and fibers, with the dominant color being green. This study found that the size of microplastics in indoor schools is mainly less than 500 μm, which can pose a threat to human health through inhalation. The annual exposure of students to microplastics is estimated to be in the range of 0.025 to 0.115 mg/kg-Bw/year.