Airborne Microplastics in Indoor and Outdoor Environments at Universiti Teknologi Malaysia, Kuala Lumpur Campus

Airborne microplastics (MPs) have been reported globally in both indoor and outdoor environments, raising concerns about potential public health risks. However, the occurrence of airborne MPs indoors and outdoors remains inadequately understood despite their simultaneous presence in both environments. Herein, the physical and chemical characteristics of airborne MPs were investigated from December 2022 to January 2023 in both indoors and outdoors at Universiti Teknologi Malaysia, Kuala Lumpur, Malaysia. Sampling was conducted on weekdays and weekends over four weeks using active samplers. The results revealed the presence of airborne MPs in both indoor and outdoor environments, with an average abundance of 7.36 MPs/m³ and 1.70 MPs/m³ during weekdays, and 5.53 MPs/m³ and 1.94 MPs/m³ during weekends, respectively. The airborne MPs indoors were dominated by MPs with a size greater than 500µm, displaying larger dimensions compared to outdoor MPs. Moreover, both indoor and outdoor airborne MPs exhibited similar characteristics in terms of color and shape, with transparent-colored fibers being the predominant feature in both environments. The identified polymer types through μ-Raman spectroscopy were acrylonitrile butadiene styrene (ABS), polyvinyl alcohol (PVA) and nylon 12. The average daily inhale (ADI) for all age groups was notably higher indoors, indicating that individuals may experience greater exposure to MPs indoors compared to outdoors. This preliminary study provides the baseline for MPs occurrence in suspended air, both indoors and outdoors, in Malaysia.