Many ecologists share the view that to know how microplastics transition through global systems is necessary to address the pollution problem. This appears possible by examining the atmospheric patterns that plastic pollution causes. Many of the plastic particles that end up in the atmosphere are older particles (or ‘legacy particles’) thrown up from the seas by wave action.
This has led scientists to put forwards the notion of the ‘microplastic cycle’. This means something akin to global biogeochemical cycles (such as those of nitrogen, carbon, and water). It follows that microplastic patterns and global distribuiton displays what are quite distinct atmospheric, oceanic, cryospheric, and terrestrial residence times. To a degree these ecological patterns are predictable.
This predictability has enabled the scientists,from S.J. & Jessie E. Quinney College of Natural Resources (Utah State University), to calculate that plastics can remain airborne for up to six-and-a-half days. This is sufficiently long, given prevailing meterologocal factors, for microplastic particles to traverse from one continent to another.
As well as seas, the research also identifies a secondary source for the re-emission of plastics. This is dust, primarily the dust produced from agricultural fields. When plastics are introduced to the soil from fertilizers (with the material drawn from waste treatments plants), a large proportion enters the atmosphere through wind. The activity of wind is also important in towns and cities, causing plastic particles to be taken up into the air.
Using this knowledge, the researchers hope to improve their predictive model and use this to address the pollution problem, such as understanding differences between wet climates and dry ones, mountainous regions compared with flatlands, and so forth.
The research appears in the science journal Proceedings of the National Academy of Sciences, where the paper is titled “Constraining the atmospheric limb of the plastic cycle.”
