plastic microfibers stay in the atmosphere much longer than spherical particles https://www.mpg.de/21360687/micrplastic-atmosphere?c=12035149
How far microplastics travel in the atmosphere depends on particle shape, according to scientists at the University of Vienna and the Max Planck Institute for Dynamics and Self-Organisation in Göttingen: While spherical particles settle quickly, microplastic fibers stay in the atmosphere much longer. Thus they might even reach the stratosphere.
particles into a global atmospheric transport model.