LOUISVILLE, Ky. (WAVE) - We are used to precipitation in the form of rain, snow, sleet, hail, graupel, and freezing rain, but recently scientists have noticed something else falling from the sky.
Plastic. Tiny chunks of plastic have been carried by the wind and falling with raindrops, according to a recent study. The microscopic particles of plastic bottles and microfibers from clothes are less than 5 millimeters. Their small size makes it easy for them to become part of the Earth's atmospheric cycles.
For 14 months, scientists collected air and rainwater samples. In 11 national parks and protected areas in the western U.S., researchers used a "wet" and "dry" bucket to collect their samples. Rain would trigger sensors that closed the "dry" bucket but kept the "wet" one open. Once it would become sunny, the "dry" bucket collected particulates in the air while the other remained closed. They found that more than 1,000 metric tons of microplastic particles precipitate into 11 protested areas in the western United States each year. The 1,000 metric tons of microplastic is equal to 120 million plastic water bottles, according to the study. What was once thought to be pristine areas of land have been contaminated by plastic rain.
In about a year, 98 percent of samples contained microplastics. The particles carried by the wind were much smaller than those dropped by the rain. Researchers said microfibers, like from clothing, comprised 70% of synthetic materials in dry samples and 66% in wet samples.
Microplastics could be acting as condensation nuclei. Water vapor condenses on condensation nuclei to help form clouds.
Plastics truly never go away. They break down into smaller and smaller particles as the years go on.
Scientists continue to watch the impacts microplastics may have on our environment. They may change how the soil absorbs or releases heat and impact microbes and other organisms living in the soil and oceans.
There’s still a lot of research still to be done on this subject.