Researchers have discovered microplastics in clouds above mountains, raising questions about their role in cloud formation and weather patterns. In a study published in Environmental Science & Technology Letters, scientists analyzed these tiny plastic fragments, typically smaller than five millimeters, which originate from everyday items like clothing, packaging, and car tires.
The team, led by Yan Wang, collected 28 cloud liquid samples from Mount Tai in eastern China. Their analysis revealed that lower-altitude, denser clouds had higher concentrations of microplastics. These particles were primarily composed of common polymers such as polyethylene terephthalate, polypropylene, polyethylene, polystyrene, and polyamide, with sizes mostly under 100 micrometers, though some reached up to 1,500 micrometers. Notably, older and rougher particles had increased levels of lead, mercury, and oxygen on their surfaces, potentially facilitating cloud development.
To trace the microplastics’ origins, the researchers developed computer models, indicating that the particles predominantly came from populated inland areas rather than the ocean or nearby mountains. Laboratory experiments showed that microplastics exposed to cloud-like conditions (ultraviolet light and filtered cloud-sourced water) became smaller and rougher compared to those in pure water or air. These altered particles also had higher concentrations of lead, mercury, and oxygen-containing groups.
These findings suggest that clouds can modify microplastics in ways that might influence cloud formation and the distribution of airborne metals. The study concludes that further research is necessary to understand the full impact of microplastics on clouds and weather.