Microplastics' shape determines how far they travel in the atmosphere

A Cornell University collaboration has developed a model to simulate the atmospheric transport of microplastic fibers and shows that flat fibers travel farther in the lower atmosphere, and are more prevalent, than spherical fibers. Previous studies assumed these fibers to be spherical.

The modeling has the potential to help scientists determine the sources of the pervasive waste -- which could inform policy efforts to reduce it.

The group's paper published in Nature Geoscience.

By treating flat fibers as spherical or cylindrical shaped, prior studies had overestimated their rate of deposition. Factoring in the fibers' flat shape means they spend 450% more time in the atmosphere than previously calculated, and therefore travel longer distances.

In addition, the modeling suggests the ocean may play a larger role in emitting microplastic aerosols directly into the atmosphere than previously known, according to Qi Li, assistant professor in the Department of Civil and Environmental Engineering and senior author of the paper.

"We can now more accurately attribute the sources of microplastic particles that will eventually come to be transported to the air," she said. "If you know where they're coming from, then you can come up with a better management plan and policies or regulations to reduce the plastic waste. This could also have implications for any heavy particles that are transported in the lower atmosphere, like dust and pollen."

The research was supported by the National Science Foundation, and computational resources were provided by the National Center for Atmospheric Research.