Electric dryers release thousands of microplastic fibers into the air after each use

We know that washing machines release thousands of microfibers (a common type of microplastics) into the water. But rotary dryers are also a problem. A new study has found that dryers are the main source of microfiber pollution in the atmosphere, with each dryer responsible for releasing up to 120 million microplastic fibers into the air each year.

Image credit: Unsplash/Creative Commons.

Synthetic fibers such as polyester and nylon are widely used in the garment industry, with the production of synthetic clothing increasing every year. but there is a problem. During washing, these microfibers can be released into the environment. So far, most studies have focused on washing machines and microfibers, a problem that has been partially solved by treating wash water at sewage plants.

But that’s not the case with electric clothes dryers, which release clumps of microfibers directly into the environment, with nothing left to filter. In the United States and Canada, more than 80% of households use clothes dryers and the numbers of use are increasing in developing countries, as more and more people are buying (and wanting) dryers.

In a new study, researchers at the City University of Hong Kong and the State Key Laboratory for Marine Pollution (SKLMP) explored the role of household dryers as sources of microfiber pollution — and estimated that between 90 million and 120 million microfibers are produced and released into the atmosphere by each dryer every year. general.

“Home clothes dryers can be an important mechanism for releasing textile microfibers into the surrounding atmosphere. Because vented air is not normally treated, microfibers are emitted directly through a vent tube connected to the dryer with ambient air, both indoors and outdoors,” the researchers wrote in their paper. .

Dryers and Microfibers

The team dried the polyester and cotton garments on separate 15-minute cycles, using a dryer that had a vent tube outside. Then they collected and counted every airborne particle that came out of the hole. Both cotton and polyester clothes produced microfibers, likely due to the clothes rubbing against each other in the dryer.

Image credit: researchers.

For both fabrics, the dryer released 1.4 to 40 times more microfibers than those produced by washing machines — based on previous studies of the same amount of clothes. The release of polyester microfiber also increased as more clothes were added to the dryer. This was not the case with cotton microfibers, as the fibers tend to clump together and cannot survive in the air.

In addition to highlighting the problem, the researchers explored a possible solution. They designed a filter that can prevent microplastics from spreading from washing machines and are now working on a similar filter for clothes dryers. However, they cautioned that microplastics could still be released into the air if people put the fibers that the filter collects in the trash.

“Before better alternatives to synthetic fibers such as polyester are achieved, it is possible to reduce the release of microfibers from dryers by installing a simple, engineered filter device at the end of the emission pipeline,” the researchers wrote.

The study was published in the journal Environmental Science and Technology Letters.

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