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.