Every day, tiny pieces of plastic, known as microplastics, find their way into our environment. Understanding how they move around, especially downward, is crucial. Scientists have been trying to figure this out using something called "drag models. " Previously, these models haven't really considered how microplastics change over time.

In this study, researchers looked at two types of microplastics: polyethylene terephthalate (PET) and polystyrene (PS). They tested both brand-new and slightly weathered versions of these microplastics. By mixing up physical traits and how these tiny plastics move, the scientists created a way to predict their downward speed based on their shape.

For PET, they were about 9. 73% off and had a pretty good match with 0. 6878 as a score. For PS, they were a bit off with 10. 42% and had a higher score of 0. 8359. Not bad, but they wanted to see if aging made a difference.

So, they added something called the carbonyl index to account for aging. This index helped them create models that considered both shape and age. These new models were even better at predicting speeds, with errors down to 3. 97% and 4. 56% for PET, and 5. 89% and 6. 91% for PS.

Plus, these models could help figure out how microplastics collected from the environment behave. As more data comes in, these models will get even better. Eventually, they could help design better ways to keep our environment clean from microplastics.

Microplastics in Motion: How Shape and Age Affect Their Journey

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