Particle properties and environmental factors control atmospheric transport and deposition of micro- and nanoplastics

Atmospheric deposition plays an important role in the global distribution and long-range transport potential of micro- and nanoplastic particles. However, our mechanistic understanding of contributing processes remains limited. While similarities in wet and dry deposition processes can be expected between micro- and nanoplastics and well-studied natural and anthropogenic aerosols (e.g. mineral dust, pollen, black carbon), no holistic theoretical framework currently accounts for specific micro- and nanoplastic properties and their inherent heterogeneity. Here, we present an integrated mathematical model of atmospheric particle transport which incorporates micro- and nanoplastic properties (size, shape, density and surface characteristics, including effects of environmental ageing) based on theory and empirical data. We find that estimated micro- and nanoplastic half-lives in air can range from seconds to weeks, depending on particle characteristics, land surface type, surface wind speed, atmospheric stratification and precipitation. Micro- and nanoplastic particles with diameters of around 1 µm and fibres have the highest potential for long-range atmospheric transport. Estimated half-lives of micro- and nanoplastics in air can range from seconds to weeks, depending on their characteristics, land surface type, surface wind speed, atmospheric stratification, and precipitation, according to an integrated mathematical description of atmospheric particle transport