Comparison of Microplastic Characteristics in the Indoor and Outdoor Air of Urban Areas of South Korea

A diverse range of studies have investigated microplastics in indoor and outdoor air. However, where and how the air was collected differ between studies, as did the methods of separation and analysis. The difference makes it difficult to compare the results of the studies, because the quantity, size, shape, and type of microplastics detected are widely diverse and depend on the detection method. Herein, we studied the number, type, size, and shape of microplastics in air samples collected from the outdoor environment and the indoor environment of buildings with active human activities, such as apartment buildings and offices. The average number of microplastics in the indoor environment was approximately 1.5 times higher than that in the outdoor environment. The indoor ventilation volume affected the amount of microplastics generated, indicating that appropriate ventilation is important for reducing microplastics in indoor environments. This study also sought ways to manage microplastics at their primary sources, which is closely linked with the living environment, by comparing how they are generated in indoor and outdoor environments.