Microplastics, these invisible particles that invade our environment, are now detected in a new space: in the clouds above the mountains. The discovery could have significant implications for our understanding of cloud formation and the impact of microplastics on climate.
An unexpected presence in the clouds
Microplastics, plastic fragments smaller than five millimeters, come from a variety of sources, including clothing, packaging and car tires.
Professor Yan Wang and his team collected 28 samples of liquid from the clouds at the summit Mount Taiin eastern China, and found that these clouds contained microplastics.
Low-lying, denser clouds contained more microplastics. The particles were made from common polymers such as polyethylene terephthalate, polypropylene, polyethylene, polystyrene, and polyamide. Microplastics tended to be less than 100 micrometers in length, although some reached 1,500 micrometers.
Formation and influence of microplastics in clouds
To determine the origin of the plastic particles in the clouds, Wang’s team developed computer models that suggested that the main source of these fragments was airflow from densely populated areas, rather than the ocean or other nearby mountains.
Laboratory experiments showed that microplastics exposed to cloud-like conditions—ultraviolet light and filtered cloud water—were smaller in size and had a rougher surface than those exposed to pure water or a cloud. Additionally, particles hit by cloud-like conditions had more groups containing lead, mercury, and oxygen.
Synthetic
The results suggest that clouds modify microplastics in ways that allow particles to influence cloud formation and the fate of airborne metals. The researchers concluded that more work is needed to fully understand how microplastics affect clouds and climate. This discovery highlights the importance of continued research into the environmental impacts of microplastics, a major issue of our time.
For better understanding
What are microplastics?
Microplastics are plastic fragments smaller than five millimeters that come from a variety of sources, including clothing, packaging and car tires.
Where were microplastics found in this study?
Microplastics were found in the clouds of Mount Tai in eastern China.
How big are the microplastics found?
The microplastics found tended to be less than 100 micrometers in length, although some reached 1,500 micrometers.
Where do microplastics in clouds come from?
Computer models suggest that the main source of these plastic debris in clouds is airflow from densely populated areas.
What effect do microplastics have on clouds?
The results suggest that clouds modify microplastics in ways that allow particles to influence cloud formation and the fate of airborne metals.
The main lesson
| Learning |
|---|
| Microplastics are found in clouds on mountain tops. |
| Lower altitude and denser clouds contain more microplastics. |
| Microplastics in clouds come mainly from densely populated areas. |
| Microplastics in clouds can affect cloud formation and the fate of metals in the air. |
| Microplastics in clouds tend to be smaller than 100 micrometers, although some are as large as 1,500 micrometers. |
| Microplastics in clouds are made from common polymers. |
| Microplastics in clouds have a rougher surface when exposed to cloud-like conditions. |
| More work is needed to fully understand how microplastics affect clouds and climate. |
Reference
Main illustration caption: Researchers characterizing the properties of microplastics present in clouds have found that these particles may play a role in cloud formation. (Mount Doi Chiang Dao)
Environmental Science & Technology Letters / Article: “Characterization of microplastics in clouds over eastern China”. https://pubs.acs.org/doi/abs/10.1021/acs.estlett.3c00729
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