This is Scientific American's 60-second Science, I'm Eilene Augenbraun.

Plastic waste breaks down into ever smaller pieces, becoming tiny enough to waft in the air and flow in the water.

A study published in June found that a person, on average, inhales or swallows at least 74,000 microscopic particles of plastic each year.

And there are multitudes of miniscule plastic beads and fibers in the environment.

So what's the most common type of microplastic?

Recent research finds that, in freshwater at least, it's tiny pieces of artificial fibers-from laundry lint.

"We were interested in the microbeads, and we found them, but we found microfibers much more prominently.

So 60 percent of the microplastics that we obtained were actually these microfibers." Sherri Mason is a chemist specializing in plastic pollution in freshwater systems at Penn State Behrend.

"I was surprised, although, like, you kind of go, 'Oh, I really shouldn't have been.' Because we all clean out our lint filters on our dryers.

You know, so we should be like, 'Oh, of course if it's coming off in the dryer, that whole process is starting in the washer.'" Synthetic textiles shed nonbiodegradable fibers, which enter wastewater-and travel beyond.