In recent times, microplastics have been found in the air people breathe, in seawater and near the summit of Mount Everest. Now, a new study has found them in clouds, raising concerns about their impact on weather patterns.
In the study, published by the American Chemical Society, researchers found microplastics in cloud samples from Mount Tai in eastern China. According to an Earth.com report, the findings showed that lower-altitude, denser clouds contain higher amounts of microplastics, comprising common polymers such as polyethene terephthalate and polypropylene.
Airborne microplastics (MPs) can travel a long distance and undergo several cloud processes through the atmosphere, the researchers explained in the paper. “The cloud MPs had a broad size range of 8–1542 μm with 60% being smaller than 100 μm and dominant shapes of fragments with diverse polymers and darker colours,” they say in the paper.
The concentrations of MPs were influenced by cloud liquid water content, source regions, and trajectory height. However, their shapes and sizes seemed to be linked to long-range transport or localised sources. The rougher microplastics consisted of toxic substances such as lead and mercury on their surfaces, which could facilitate cloud development.
The researchers used computer models to trace the origins of these microplastics, indicating inland areas as the primary source, rather than oceans or neighbouring mountains, Earth.com’s report revealed.
Further laboratory experiments revealed that microplastics exposed to cloud-like conditions, involving ultraviolet light and filtered cloud-sourced water, can change in size and texture. The report elaborated that these charged particles have more lead, mercury, and oxygen-containing groups, indicating that clouds alter microplastics in ways that could impact cloud formation and the distribution of airborne metals.
These findings add to the growing concern about expanding microplastic pollution and its impact on humans and the environment. In June, a study published in the journal Physics of Fluids found that humans might be inhaling about 16.2 bits of microplastic every hour, which is equivalent to a credit card over a week.
To address the rising impact of microplastics on health and the ecosystem, researchers have also been working on potential technology that can extract microplastics from water and air. For instance, a study published in the journal Advanced Materials in January showed that researchers in South Korea have developed a novel water filter that can remove 99.9 per cent of microplastics.