Human inhalation exposure assessment of the airborne microplastics from indoor deposited dusts during winter in Dhaka, Bangladesh

Microplastic (MP) contamination has become a concern due to its ubiquitous presence. Recent studies have found MPs to be present in multiple human organs. This study was carried out to evaluate the presence and characterize MPs in indoor dust deposition. Deposited dust was collected from fifteen households in Dhaka city. The samples underwent quantification of MPs using stereomicroscopy. Fourier Transform Infrared (FTIR) spectroscopy was performed to understand the polymer composition. MPs of the size group ranging from 50 to 250 μm were the most dominant. The deposition rates varied from 7.52 × 10³ MPs/m²/day to 66.29 × 10³ MPs/m²/day, with the mean deposition rate being 34 × 10³ MPs/m²/day. Notably, the number of occupants and the height of the sampling location above the ground level were found to influence the deposition rates. Various polymers, including polyester (PET), polyethylene (PE), Nylon, and polypropylene (PP), were identified. The estimated mean inhalation exposure was 2986 ± 1035 MPs/kg-BW/day. This work highlights the need for additional research to explore indoor microplastic deposition and its potential effect on human health in the densely inhabited and severely polluted megapolis of Dhaka, Bangladesh.