Microplastic particles, even in the most remote corners of our planet, have become a cause for concern. The mystery lies in how these relatively large and mostly fiber-like microplastics travel, reaching places like Arctic glaciers and ice sheets.
Atmospheric transport models suggest that such large particles would normally fall out of the atmosphere near their sources.
To shed light on this paradox, an interdisciplinary group of scientists from the University of Vienna, Austria, and the Max Planck Institute for Dynamics and Self-Organization in Göttingen, Germany, conducted an intriguing study that combined laboratory experiments and model simulations.
Dynamics of traveling microplastics
In laboratory experiments led by Mohsen Bagheri of the Max Planck Institute for Dynamics and Self-Organization, the team focused on understanding the settling dynamics of microplastic fibers traveling in the atmosphere.
Surprisingly, there has been very little data on this topic in the literature, mainly due to the challenges of conducting controlled experiments with such small particles.
The team took advantage of advances in 3D printing with submicron resolution and developed a new experimental setup to track individual microplastics in the air.
Through their experiments, they found that microplastic fibers settled significantly more slowly than spheres of the same mass.
Bagheri notes, “With advances in 3D printing at submicron resolution and the development of a new experimental setup that allows tracking of individual microplastics in the air, we were able to fill this knowledge gap and improve existing models in this study.”
The path of non-spherical particles
To further investigate the phenomenon of microplastic travel, the researchers integrated a model describing the settling process of non-spherical particles into a global atmospheric transport model.
The differences between the travel of spherical and fibrous microplastics were large. The model revealed that fibers as long as 1.5 mm can reach the most distant regions of Earth, while spheres of the same mass settle much closer to their plastic source regions.
Daria Tatzii is the first author of the study and a member of the Department of Meteorology and Geophysics at the University of Vienna.
“With the new laboratory experiments and modeling analysis, we certainly reduce the uncertainty about the atmospheric transport of fibers and can finally explain through modeling why microplastics reach very remote regions of the planet,” Tatsius explained.
“An important result of the study is that our analysis is applicable not only to microplastics, but also to any other particles such as volcanic ash, mineral dust and pollen.”
Consequences of the long-distance travel of microplastics
The study’s findings have broad implications for our understanding of atmospheric processes and potential risks to the environment.
The model shows that plastic fibers can reach greater heights in the atmosphere than spheres of the same mass.
Andreas Stoll is the initiator of the study and a researcher at the University of Vienna. It highlights the possible consequences.
“This could have implications for cloud processes and even stratospheric ozone, as it seems possible that microplastic fibers are abundant in the upper troposphere and even reach the stratosphere.” For example, we cannot rule out that the chlorine contained in these particles is harmful to the ozone layer,” Stoll said.
“Currently, however, we don’t even know how much plastic and in what sizes and shapes is released into the atmosphere, and we also don’t know what happens to it in the extreme conditions of the upper troposphere and stratosphere.” We are missing a lot of basic data. But given the dramatic increase in global plastic production, we need to be vigilant,” Stoll concluded.
Unique shapes of microplastic particles
Amid the uncertainty surrounding microplastics, one thing is clear: the individual forms of these particles must be taken into account when assessing their impact on the environment.
Their research highlights the importance of addressing the complex dynamics of microplastic fiber deposition and their potential implications for atmospheric processes and ozone depletion.
By combining innovative laboratory experiments with advanced modeling techniques, researchers have made significant progress in unraveling the mysteries surrounding the global journey of microplastic particles.
However, further research and data collection is needed to fully understand the extent of plastic pollution and its impact on the environment.
What does the future hold?
In summary, the study sheds light on the surprising journey of microplastics to some of the most remote regions on earth.
Through laboratory experiments and modeling, the scientists revealed the slower settling rates of fiber-like microplastics compared to spherical particles of the same mass.
These findings, combined with the potential for microplastic fibers to reach high altitudes in the atmosphere, introduce implications for cloud processes and ozone depletion.
With the ever-increasing production of plastic, it is critical that more data be collected and further research conducted to reduce the environmental risks associated with microplastic pollution.
As we strive to protect our planet’s delicate ecosystems, it is clear that the particular shapes of microplastic particles cannot be ignored in our research.
The full study is published in the journal Environmental Sciences and Technologies.
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