Nowadays, there is a growing concern about the global air pollution situation. There are large quantities of microscopic plastic particles floating in the air, which span seven continents and four oceans, floating above the earth. This environmental problem is likely to become more serious in the future and could have serious implications for human health.
In the process of global atmospheric circulation and transportation, pollutant particles are constantly moving, diffusing, and deposited in different locations. No place is free from pollution. There are already computer models that reveal how these microplastics are transported over long distances across the globe and which areas are likely to be hotspots with the highest levels of microplastics.
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However, these computer models assume that these plastic particles are spherical, ignoring the fact that many of the micro-plastic particles are far from spherical, and even take the shape of slender strips, some even reaching the shape of a string that is 100 microns long and only 2 microns wide. But the shape of the microplastic particles can greatly affect their trajectory in the atmosphere.
A recent study published in the journal Nature Geosciences argues that:When estimating the movement and deposition of microplastic particles in the atmosphere, their different shapes should be fully considered in order to better simulate their real trajectory.
A team at Cornell University in the United States developed a model in which there are two shapes of microplastic particles, one spherical and the other elongated strip, which they used to study the transport and deposition behavior of microplastic particles of different shapes and sizes in the atmosphere.
It was found that the elongated strip microplastic particles had much smaller aerodynamic particle size and a much lower sedimentation rate than the spherical microplastic particles with the same volume. That is to say,Elongated strips of microplastic particles remain in the atmosphere longer and travel farther.
The team also found that because the microplastic particles collected from the sampling were different in shape and thickness, they also had elongated strips of particles, some of which were very thin and some of which were very thick, so if the thickness of the plastic particles was taken into account, they estimatedThe residence time of elongated strips of plastic particles in the atmosphere will increase by 4 compared to spherical plastic particles5 times, then correspondingly, the distance will be much farther to move.
The problem of microscopic plastic particles in the atmosphere is likely to become more and more serious. Due to the lack of effective ways to dispose of plastic waste, plastic waste will break down into tiny particles over a longer period of time and enter the soil, water or atmospheric circulation. In the future, more microplastics may enter the environment we live in and enter the atmosphere, making the problem more and more complex.
Previous studies have pointed out that the ocean has become the hardest hit area of microplastic particle pollution, from the offshore area to the inaccessible ocean, from the equator to the polar regions, from the surface of the ocean to the continental shelf of the seabed, from the animals in the sea to the plants in the sea, all of which have been detected in the microplastic particles. It can be said thatPlastic pollution is already permeating the entire ocean system
Research on the global movement patterns and processes of microplastic particles has only just begun, and it is hoped that more research results will help us solve this problem in the future.
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This article is a work of popular science China-Star Project.
Produced by the Science Popularization Department of the China Association for Science and Technology.
Producer: China Science and Technology Press***, Beijing Zhongke Galaxy Culture Media***
Author丨Zeng Xinyue, Science Popularization Creator Review丨Liu Lu, Professor, School of Chemistry and Molecular Engineering, East China Normal University, Doctoral Supervisor, Editor-in-Charge丨Zhong Yanping, Qi Yuan (intern).