Atmospheric microplastics in Handan, China: characteristics, seasonal variations, and human exposure risk

Atmospheric microplastics (AMPs), as emerging pollutants, have attracted widespread attention due to their potential ecological and health risks. This study conducted a 1-year monitoring campaign of deposited microplastics (DAMPs) and suspended microplastics (SAMPs) in the urban area of Handan, an industrial city in northern China. The research systematically evaluated their temporal distribution patterns, correlations with meteorological variables and conventional air pollutants, and quantified both their ecological deposition flux and respiratory exposure risks. Results showed that the annual average abundances of DAMPs and SAMPs were 246.5 ± 91.4 items/m²/day and 5.2 ± 3.0 items/m³, respectively, with significant seasonal variations-highest in winter and lowest in autumn. The dry deposition flux in December reached a maximum of 1.25 × 10¹⁴ items. AMPs were significantly positively correlated with PM₂.₅, PM₁₀, SO₂, NO₂, and CO, suggesting that their primary sources are industrial and vehicular emissions. The estimated annual total dry deposition was approximately 9.82 × 10¹⁴ items, with about 2.3 × 10¹³ entering aquatic systems and 5.46 × 10¹⁴ deposited onto farmland. Exposure assessment revealed that infants and toddlers had the highest estimated daily intake (EDI), and males generally experienced higher exposure than females, with the highest annual exposure (~ 55,220 items) observed among males aged 30-40. This study highlights the environmental behavior and health risks of AMPs in Handan, an industrial city in northern China, and provides scientific support for pollution control and public health policymaking.