Every spin cycle releases millions of microplastics — and dryers are a major culprit

"I can't do laundry without a dryer…"

In summer, clothes hung out to dry can take forever, and dryers have become less of a luxury and more of a household essential.

During the rainy season in particular, air-drying is nearly impossible, and many single-person households make regular trips to coin laundries just to use a dryer.

The problem is a serious side effect that comes with every use: the high-heat drying process causes clothes to shed "microfibers" — a type of microplastic.

Microfibers released by dryers are also difficult to avoid. They disperse into the air almost immediately and enter the body through breathing.

According to research published Sept. 3 last year in the international journal Environmental Toxicology and Chemistry by the Desert Research Institute (DRI) and environmental groups, a single dryer cycle releases an average of 138.6 milligrams of microfiber material into the outside air.

In terms of particle count, that means a single dryer cycle releases millions of microplastic particles.

The research team fitted mesh nets over the external exhaust vents of vented dryers in seven US households for three weeks. Each household used their dryer as normal during that period, and the team analyzed the volume and composition of material collected in the nets to measure microfiber emissions.

Assuming the approximately 82.21 million electric dryers in the United States each run an average of 311 cycles per year, the team estimated that roughly 3,500 metric tons of microfibers are released annually — the equivalent of 700 five-ton trucks.

Microfibers are a type of microplastic. Because most common fabrics are made from petroleum-based synthetic fibers, clothes shed microplastics as they are damaged by the drying process. When hot air is expelled during drying, microplastics spread into the surrounding environment and enter the body through inhalation.

Dryer filters often fail to capture these microfibers, which are far thinner and shorter than ordinary dust particles. Microplastics that slip through the filter are discharged into either the air or water, depending on the type of dryer.

As is widely known, microplastics do not break down or get expelled from the body — they accumulate in tissue. Research into their health effects is still ongoing.

However, a growing body of research shows that microplastics can harm the cardiovascular system and other tissues. Some analyses suggest they can also disrupt the immune system and hormonal function, potentially triggering inflammation and cellular damage.

The problem extends beyond home dryers. The US environmental group 5 Gyres Institute published findings last November on microfiber emissions from coin laundries, collecting samples from the exhaust vents of 10 laundromats around the San Francisco Bay Area.

The results estimated that a single laundromat releases between about 8 million and 47 million microfibers per week. Scaled up to all laundry facilities across San Francisco, the calculations suggest up to 1,100 trillion fibers could be released into the air each year.

While the home-dryer study measured emissions by fitting filters over exhaust vents, this study is notable for confirming that fiber deposits in the air around laundromats actually increase — not just that fibers exit the machines.

The research team said commercial dryers that handle large volumes of clothing should be treated as a major point source of urban microfiber pollution, and called for additional filters and regulatory standards.

The concern goes beyond local air contamination near dryers — these machines may be a significant source of microplastic emissions into the broader atmosphere.

The dryers used in those studies were vented models that expel hot air directly outside. Many households in South Korea use heat-pump dryers, which do not discharge hot air directly into the environment.

Even so, clothes still shed microfibers as they tumble and rub against the drum. Fibers that escape the filter can migrate toward the heat exchanger or condensate water. While they do not fly out into the open air, small plastic fiber fragments can still end up in waterways through drainage.

As consumer awareness of microplastics grows, manufacturers are developing technology aimed at minimizing microfiber release — particularly by improving filter performance to capture finer particles and redesigning drum movement to reduce fabric abrasion.

Of course, it is unrealistic to ask consumers to stop using dryers simply because they emit microplastics. With the rainy season and fine dust recurring year after year, dryers have firmly established themselves as a household necessity. Still, some voices are calling for a shift in habits — making air-drying the default where possible and reducing how often the dryer is used.

The DRI research team said small behavioral changes — such as air-drying clothes — "are ways to reduce microplastic emissions and protect ourselves."

Meanwhile, dryers are also considered among the most carbon-intensive home appliances due to their high energy consumption. Research has found that running a home dryer just once causes environmental harm equivalent to producing and disposing of more than 100 single-use plastic cups.