Atmospheric microplastics deposition in a central Indian city: Distribution, characteristics and seasonal variations

Atmospheric microplastics (AMPs) transport and deposition in urban areas contribute to microplastics pollution. The present study investigates AMPs deposition, characteristics, potential sources, and the influence of meteorological factors in a central Indian city. AMPs were collected over three land-use types, viz. institutional, commercial, and industrial areas, during four seasons: summer, monsoon, autumn, and winter. The deposition flux of microplastics ranged from 212.53 ± 52.32 to 543.25 ± 71.23 particles/m²/day. The AMPs were predominantly fibres (87.84 %), followed by films (5.43 %), with particle size <1000 μm contributed 43.67 %. The predominant polymer types identified were polyethylene terephthalate (PET, 37.39 %), nylon (20.49 %), and polypropylene (PP, 10.27 %). Higher deposition fluxes were recorded in summer, with 491.06 ± 73.37 particles/m²/day. Correlation analysis revealed a negative correlation between rainfall and AMPs deposition, suggesting a potential cleaning role of rainfall. The estimated annual deposition flux of AMPs in Nagpur city was 3.22 × 10¹³ particles. Higher AMPs deposition was attributed to plastic waste littering, industrial emissions, and textiles. The estimated mean annual inhalation exposures of AMPs of size 50-250 μm for children and adults were 7375.84 ± 1312.89 and 3738.17 ± 665.39 MPs/kg-bw/year, respectively. The findings of this study contribute to understanding the fate of AMPs and its implications for human exposure. The findings underscore the importance of reducing and managing plastic waste.