Airborne microplastics in China: Assessing urbanization, weather factors and policy implications from the nationwide study

This study presents the first nationwide assessment of atmospheric microplastics in China that systematically investigates the sources, distribution patterns, and governing factors of atmospheric microplastics across China through an integrated approach combining: year-round monitoring of both deposited (DAMPs) and suspended atmospheric microplastics (SAMPs) in Ningbo, and nationwide analysis of DAMPs data from 30 cities. Results showed an average DAMP flux of 473.9 ± 349.3 items m⁻² d⁻¹ and SAMP concentration of 0.15 ± 0.08 items m⁻³ in Ningbo, with an inverse seasonal relationship between SAMPs and DAMPs and a washout ratio of (1.02 ± 0.42) × 10⁶ confirming rainfall's crucial role in microplastic removal. Multivariate analysis identified precipitation, temperature, and wind speed as key environmental drivers, while socioeconomic factors including population and GDP per capita strongly influenced spatial distribution of DAMPs. Nationwide analysis of 30 cities also established robust correlations between deposition fluxes and socioeconomic indicators. Based on this strong statistical relationship we developed the first predictive model for China, estimating total annual deposition at 1745 ± 619 tonnes, with wealthier coastal regions exhibiting 2.3–5.1 times higher fluxes than inland/less-urban areas. These findings quantify the coupled influence of meteorological and anthropogenic drivers on atmospheric microplastic pollution. This assessment provides a scientific basis for targeted mitigation, suggesting prioritized stormwater management in high-deposition coastal megacities and enhanced waste infrastructure in developing inland regions to address emission sources.