Papers

61,005 results
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Article Tier 2

Modeling the Gravitational Settling of Microplastic Fibers in the Atmosphere

Researchers developed and applied a model for gravitational settling of microplastic fibers in the atmosphere, examining how fiber shape and size influence atmospheric residence time and deposition patterns to better understand the global atmospheric transport cycle of microplastics.

2022 Digital Commons - USU (Utah State University)
Article Tier 2

The atmospheric settling of commercially sold microplastics

Researchers measured the gravitational settling velocities of commercially available glitter microplastics (0.1-3 mm nominal diameter) and synthetic fibers (1.2-5 mm length) in air, finding that non-spherical shapes cause complex settling behaviors that deviate substantially from spherical particle models used in atmospheric transport models.

2025
Article Tier 2

Modeling Microplastic Transport in the Marine Environment: Testing Empirical Models of Particle Terminal Sinking Velocity for Irregularly Shaped Particles

Researchers tested multiple drag models for predicting the terminal settling velocity of irregularly shaped microplastic particles in seawater, identifying three high-precision models and demonstrating that settling velocity is largely stable across ocean depths and independent of initial particle velocity, improving the accuracy of marine microplastic transport simulations.

2023 ACS ES&T Water 12 citations
Article Tier 2

Atmospheric transport of microplastic particles as a function of their size and shape

Researchers investigated the atmospheric transport and settling of microplastic particles as a function of size and shape, implementing a shape-correction parameterization for fiber-shaped particles in an atmospheric transport model to better represent their reduced gravitational settling velocity compared to spheres. The study showed that non-spherical fibers experience greater atmospheric drag, increasing their residence time and transport distance, and that including shape effects improved agreement between model output and ground-based measurements.

2022
Article Tier 2

Gravitational settling of microplastic fibers: experimental results and implications for global transport

This study measured the gravitational settling velocities of microplastic fibers and found that their non-spherical shape causes them to settle much more slowly than spheres of the same volume. Current atmospheric transport models that assume spherical particles significantly underestimate how long fibers remain airborne. These results have important implications for predicting how far microplastic fibers can travel before depositing.

2023
Article Tier 2

Terminal Settling Velocity of Cylindrical Rods with Various Geometries Applicable to Atmospheric Microplastics

Researchers measured how the shape of cylindrical microplastic fibers affects their settling speed through air, finding that curved and V-shaped fibers fall significantly faster than straight ones — up to 57% faster for V-shaped rods — which matters for predicting how airborne microplastics disperse in the atmosphere.

2024 Proceedings of the ... International Conference on Fluid Flow, Heat and Mass Transfer
Article Tier 2

Normalized Settling Velocity Governs Short-Range Transport of Atmospheric Microplastics

Wind tunnel experiments showed that how fast a microplastic particle settles under gravity—its normalized settling velocity—is the single best predictor of how far it travels through the air before landing. This finding helps fill a major gap in atmospheric microplastic research by enabling better models of where airborne plastic particles deposit, which affects estimates of human inhalation exposure and ecosystem contamination.

2026 ACS ES&T Air
Article Tier 2

Twist, turn and encounter: the trajectories of small atmospheric particles unravelled

Experiments and simulations studied how non-spherical solid particles (including microplastics) settle through air, finding unexpectedly complex tumbling and spiraling trajectories even at low speeds. These insights improve predictions of how airborne microplastic particles travel and deposit across landscapes.

2025 Journal of Fluid Mechanics 1 citations
Article Tier 2

Microplastic shape affects travel distance

Researchers found that microplastic shape significantly influences atmospheric transport distance, with fibre and complex-shaped particles travelling farther than spherical ones assumed in most models, helping explain the detection of microplastics in remote locations such as Antarctica and Mount Fuji.

2024 C&EN Global Enterprise
Article Tier 2

Settling velocity of microplastic particles of regular shapes

This study measured the sinking velocities of spherical, cylindrical, and filament-shaped microplastic particles ranging from 0.5 to 5 mm, finding that shape strongly determines how quickly particles settle through the water column. Understanding settling behavior is essential for modeling how microplastics are transported and deposited in marine environments.

2016 Marine Pollution Bulletin 457 citations
Article Tier 2

A new model for the terminal settling velocity of microplastics

A new empirical model for the terminal settling velocity of microplastics was developed and validated using 1,343 experimental measurements covering a range of particle shapes and materials. The model improves predictions of microplastic sedimentation rates, which are critical for understanding how plastic particles are transported and deposited in water bodies.

2022 Marine Pollution Bulletin 68 citations
Article Tier 2

Long-distance atmospheric transport of microplastic fibers depends on their shapes

Researchers developed a theory-based settling velocity model for microplastic fibers in the atmosphere that accounts for fiber shape and cross-sectional dimensions, finding that correctly characterising flat fibers rather than treating them as cylinders increases estimated mean atmospheric residence time by over 450%, suggesting the ocean is a major source of airborne plastic and that long-range transport is far more efficient than previously thought.

2023 5 citations
Article Tier 2

Lagrangian tracking of particles settling through the atmosphere: influence of particle shape on its dispersion

Researchers launched instrumented balloon experiments as part of the IMPACT field campaign in northern Finland to track non-spherical particle settling through the atmosphere, finding that particle shape significantly influences dispersion trajectories and that existing spherical-particle models underestimate the spread of realistic atmospheric particles such as microplastics.

2025
Article Tier 2

Empirical Shape-Based Estimation of Settling Microplastic Particles Drag Coefficient

This study experimentally measured the settling behavior of flat square microplastic particles in water, finding that shape significantly affects sinking speed and drag compared to spherical particles. Understanding how microplastic shapes influence settling is essential for modeling where plastics accumulate in rivers and ocean sediments.

2023 Journal of Marine Science and Engineering 2 citations
Article Tier 2

Coupled CFD-DEM modelling to assess settlement velocity and drag coefficient of microplastics

Researchers used computational fluid dynamics coupled with particle simulations to model how the size, shape, and density of microplastics affect their settling velocity and drag in water. Accurate physical models of microplastic behavior are essential for predicting where particles accumulate in rivers, lakes, and the ocean.

2020 1 citations
Article Tier 2

Sinking rates of microplastics and potential implications of their alteration by physical, biological, and chemical factors

Researchers conducted sinking experiments with diverse microplastic particles and found that sinking velocity depends not only on density and size but also on particle shape, and that biofouling and weathering can substantially alter sinking rates with implications for how microplastics distribute through the water column.

2016 Marine Pollution Bulletin 595 citations
Article Tier 2

Is plastic dust different from mineral dust? Results from idealized wind tunnel experiments.

Researchers conducted wind tunnel experiments to compare how plastic particles of different sizes detach from flat surfaces in wind compared to mineral dust particles. Plastic particles required higher wind speeds to become airborne than mineral dust of similar size, likely due to shape differences. These findings inform atmospheric transport models for predicting how far and how much microplastic can be carried by wind across the landscape.

2023
Article Tier 2

Improved Settling Velocity for Microplastic Fibers: A New Shape-Dependent Drag Model

A new shape-dependent drag model was developed to improve the accuracy of settling velocity predictions for microplastic fibers, addressing a major limitation of existing drag models that significantly underpredict fiber settling in aquatic environments.

2021 Environmental Science & Technology 85 citations
Article Tier 2

Experimental investigation of the fallout dynamics of microplastic fragments in wind tunnel: The BURNIA agenda

Wind tunnel experiments were used to measure the settling velocity of airborne microplastic fragments of PET, PVC, and low-density polyethylene, providing the first empirical data to model how plastic particles fall out of the atmosphere.

2024 Journal of Hazardous Materials Advances 5 citations
Article Tier 2

A physics-based and orientation-aware method for the direct calculation of  the settling speed of prolate spheroidal particles in the atmosphere : theoretical basis and comparison to laboratory and CFL data

Researchers developed a physics-based, orientation-aware method for calculating the settling speed of prolate spheroidal particles such as microplastic fibres in the atmosphere, grounding the approach in theoretical drag and orientation models rather than purely empirical fits and validating it against laboratory and CFD data.

2025
Article Tier 2

Atmospheric transport dynamics of microplastic fibres

Researchers examined the atmospheric transport dynamics of microplastic fibres within boundary layer flows, comparing their motion to mineral grain transport and finding key differences in behaviour that have important implications for modelling the long-range atmospheric dispersal of microplastics to remote and rural locations.

2025
Article Tier 2

On some physical and dynamical properties of microplastic particles in marine environment

This study examined the physical and dynamical properties of microplastic particles in marine environments, using modeling to predict how particle shape, density, and size govern transport, dispersion, and accumulation patterns.

2016 Marine Pollution Bulletin 629 citations
Article Tier 2

Settling velocity of microplastic particles having regular and irregular shapes

Researchers measured how quickly microplastic particles of various shapes settle through water, testing 66 different particle types including spheres, cylinders, fibers, and irregular fragments. They found that particle shape significantly affects settling speed, with fibers and flat shapes sinking more slowly than spheres of the same size. The study provides new equations for predicting where microplastics end up in oceans and waterways based on their shape.

2023 Environmental Research 86 citations
Article Tier 2

Shape matters: long-range transport of microplastic fibers in the atmosphere

This study modeled the long-range atmospheric transport of microplastic fibers, finding that their elongated non-spherical shape causes them to travel much farther than spherical particles before settling. This helps explain why microplastic fibers are found even in the most remote locations on Earth, far from any plastic pollution source.

2023 arXiv (Cornell University) 2 citations