Visual: Amy Bader/Getty Images
Microplastic fibers are swirling in the air around us and under our feet. But how are they affecting our health?
BY MATT SIMON
TAKE A LOOK around. If you're on a bus or train, you're likely sitting on a plastic seat surrounded by people in synthetic clothing, all of it shedding particles as they move. If you're on the couch or in bed, you're sunk into the embrace of microfibers. The carpet underneath you is probably plastic, as is the coating of a hardwood floor. Curtains, blinds, TVs, coasters, picture frames, cables, cups — all of it's either wholly plastic or coated in plastic.
Whereas the takeover of packaging was a conspicuous revolution for plastic bags and bottles, the material's infiltration of every other aspect of our lives has been a quiet coup. While scientists have been untangling the complex dynamics of microplastics in the atmosphere, others have turned their attention to how the omnipresent plastic products around us are bastardizing our indoor air.
In 2015, researchers sampled the living rooms of two apartments near Paris, each home to two adults and a child, as well as a university office where three people worked. They only sampled air when people were present in the rooms, both at a height of about 4 feet to gather what the subjects are breathing, and a half inch off the ground to determine the deposition rate of dust. The researchers also took samples from vacuum cleaner bags the occupants had used in the two apartments.
In the apartments, they counted about half a fiber floating in a cubic foot of air; in the office, it was a little under two. Based on the number of particles they caught near the floor, the researchers calculated that up to a thousand fibers are deposited per square foot each day, which matched with the number of fibers they found in the vacuum bags.
Overall, two-thirds of the fibers they tallied were made of natural materials like cotton and wool, while the remaining third were plastic. Polypropylene fibers were particularly prominent, and indeed one of the occupants clued the researchers in on the fact that they'd been sampling a room adorned with a large polypropylene carpet.
Moving over to the West Coast, another team tested indoor and outdoor air on the California State University Channel Islands campus. They found a similar concentration of microfibers suspended in the air indoors and found that microplastic fragments had become airborne as well. The more foot traffic the area had, the higher the microfiber count.
"Fibers from the synthetic clothing of students and staff passing through could easily contribute to microfiber loading of the inside air," the researchers wrote in a paper. They collected more than six times the number of microfibers indoors as they did outdoors: With little airflow inside, the particles suspend in the air, waiting to be breathed in, whereas outdoors plentiful airflow dilutes the particles.
We are all, then, like Pig-Pen from the Peanuts comics, who swirls with a perpetual aura of dust, only we're depositing our microfibers wherever we go. As you abrade a synthetic fabric — putting it on or walking around in it or sitting on the couch — its fibers "fibrillate," meaning that instead of always breaking neatly in two, fibers also shed clones of themselves, known as fibrils. Under the microscope, the fiber looks like a giant mother surrounded by tiny, curled-up offspring. One experiment found that abrading an ounce of fleece produced 60,000 microfibers, but also 170,000 fibrils that were significantly shorter and thinner than their parents, and therefore more liable to get suspended in the air around us, à la Pig-Pen.
To be clear, that was done with a standard testing machine the textile industry uses on new materials, not on humans walking around a room. To test this directly, another set of scientists recruited four volunteers to move around a space wearing four different kinds of synthetic garments. After counting the microfibers from petri dishes left in the room, they arrived at a stunning figure: Each year, you might shed a billion polyester microfibers into the air just by moving around, which would explain why all these studies find so much microplastic deposited on floors. This is based on those four specific garments, though, so your results may vary — if you wear a lot of cheap, fast fashion, you may be shedding more.
Another study in 2020 confirmed the findings from these indoor air surveys, and on longer timescales to boot. In Shanghai, researchers sampled a dorm room, an office, and a corridor of a lecture building. In the dorm, they counted up to roughly 7,000 particles deposited per square foot of floor each day, 1,200 in the office, and 1,600 in the corridor...
more...
https://undark.org/2022/12/30/book-excerpt-the-unknown-risks-of-microplastics-in-indoor-air/
F. Kaskais Web Guru
No comments:
Post a Comment