Microplastics are turning up in unusual places increasingly often as they filter into nearly every facet of life on Earth. They’ve been discovered in drinking water, food, air and even in blood. Now, scientists have found that these tiny particles might even be able to influence the weather.
Researchers reported Wednesday they detected microplastics in a majority of cloud samples taken from a mountaintop in China, in a study published in the American Chemical Society’s Environmental Science & Technology Letters.
The study traced how the microplastics ended up at their final location and discovered that they could play a role in cloud formation.
What are microplastics?
Microplastics are tiny pieces of plastic that are no larger than five millimeters, which is about the size of a single sesame seed. And they are everywhere, according to Judith Enck, president of Beyond Plastics, a group working to end plastic pollution.
“Microplastics are in the air we breathe, they’re in our drinking water, they’re in our bodies,” Enck told CNN.
Microplastics form when larger plastics break down, either by chemically degrading or physically wearing down into smaller pieces.
“If it’s plastic, you’re going to get microplastics sooner or later,” Enck said.
The smaller a microplastic is, the easier it can move through environmental cycles – like the water cycle – and ultimately end up in the human body, where its effects are worrisome but still unclear.
Most experts believe more research is needed to determine the full impact of microplastics on human health, but studies have shown that there are already some demonstrable adverse health impacts.
How could microplastics affect the weather?
The authors of Wednesday’s study found microplastics affect cloud formation, and clouds are of huge importance to the weather we experience.
Clouds produce precipitation in the form of rain, snow and everything in between. They also block sunlight, and less solar radiation means cooler temperatures.
In order for a cloud to form, water vapor – a gas – needs to turn into water droplets – a liquid. Then, many water droplets need to come together to become a cloud.
Water droplets form when water vapor interacts with tiny solid particles in the atmosphere, like dust, ash or salt from the ocean. According to the study, microplastics can now be added to that list.
These particles are hydrophilic, which means they are attracted to water. Once the first water droplets cling to microplastics and other tiny particles, more water droplets are pulled together and clouds form.
The process is akin to how a single spark can eventually set an entire field ablaze: One tiny particle in the atmosphere can set into motion a process that becomes something much bigger.
According to the study’s authors, further research must be completed to fully understand the extent to which microplastics influence cloud formation.
Could a greater concentration of microplastics lead to more clouds? Will an increase in clouds lead to more precipitation or larger swaths of cooler conditions? These questions remain unanswered.
How do microplastics get into the atmosphere?
Microplastics are tiny and light enough to get picked up by the wind and hoisted into the atmosphere.
The study’s authors found samples of microplastics in the air over Mount Tai in China, and developed computer models to recreate the journey those particles would have had to take to end up there. The models suggested that the flow of air from nearby highly populated inland Chinese cities served as a major source of the microplastics.
This suggests microplastics produced at ground level were lofted and carried large distances.
There are more microplastics found in cities than rural areas, in general, since a higher population density often leads to a higher demand for plastic products. However, rural areas are quickly catching up with microplastic production, according to Enck.