Dryer Vents Blow Hot Air & Microplastics
New research confirms that air vents on tumble dryers – rather than washing machines – may be a leading source of microplastic fibers from clothing in the environment. The findings, presented in a new report by the San Francisco Estuary Institute, provide convincing reason to hang-dry clothes and to use energy-intensive dryers sparingly, if ever.
Microplastics have emerged in recent years as one of the most concerning forms of pollution, with the insidious little particles being found, among other places, in ocean-caught fish, beer, and even placentas of unborn babies.
Kelly Moran, an SFEI senior scientist and the lead author of the report, says emerging science on microplastic fiber sources also creates a significant regional divide between the people of the United States and Canada and those of the much of the rest of the world, including Europe and New Zealand.
“Tumble dryers aren’t widely used there,” she says, explaining that people in these regions tend to hang-dry their clothes or use gentler, less abrasive – and more energy-efficient – ventless dryer machines. Rather than spew out hot – and fiber-laden – air, ventless dryers recirculate heated air inside the system while draining out evaporated water.
“These geographic differences may explain why dryer vents are an under-studied source of microplastic pollution,” Moran and her colleagues suggest in their 137-page analysis. The authors also cite research suggesting that some dryers may cause 3.5 times the shedding of microplastic fibers that some washers do.
Microplastic fibers vented from clothes dryers may be especially problematic in the United States. That’s because Americans’ household wastewater is typically processed in treatment plants which remove most plastic particles, whereas dryer-released fibers exiting buildings can be washed into storm drains that flow directly to creeks. Many European communities, Moran says, have a different system entirely by which storm drains empty into wastewater treatment plants.
The SFEI’s report suggests regulatory action that could help mitigate microplastic pollution. Moran and her colleagues propose stricter standards on apparel fabric quality to reduce shedding. Filtration systems on dryer vents could also be improved to reduce microfiber emissions. They also encourage governments to ease restrictions on using outdoor clotheslines to dry clothes.
Other Recent Posts
Artist Repurposes Shoreline Detritus
Courtney Griffith scours beaches and parks for everything from plastic to charcoal, mangled ropes and burnt wood to use in her work.
After The Fire: Scenes from Chinese Camp
One of California’s oldest Gold Rush settlements takes stock after a devastating fire — a photo essay.
Youth Group Tackles Heat Islands in Santa Rosa
A new youth advisory team convened by the Greenbelt Alliance and Latino Service Providers is exploring heat disparities in southwest Santa Rosa.
ReaderBoard
Once a month we share reader announcements: jobs, events, reports, and more.
CEQA Reforms: Boon or Brake for Adaptation?
California Environmental Quality Act updates may open up more housing, but some are sounding alarms about bypassed environmental regulations.
Repurposing Urban Lots & Waterfronts: Ashland Grove Park, Palo Alto Levee, and India Basin
In this edition of our professional column, we look at how groups are reimagining a lot in Ashland Grove and shorelines in San Francisco and Palo Alto.
Backyard Harvests Reduce Waste
A Cupertino Rotary Club program led by Vidula Aiyer harvests backyard fruit and reduces greenhouse gases.
Digging in the Dirt Got Me Into Student Climate Action
A public garden at El Cerrito High School in the East Bay inspired my love of nature and my decision to study environmental science at UCLA.
King Kong Levee: Two Miles Done, Two To Go
Two miles of levee are now in place as part of the project to protect Alviso and parts of San Jose, but construction will last much longer.
Making Shade a Priority in LA: An Interview with Sam Bloch
After witnessing fire disasters in neighboring counties, Marin formed a unique fire prevention authority and taxpayers funded it. Thirty projects and three years later, the county is clearer of undergrowth.
Moran says voluntary action at the individual level will also be helpful, primarily by avoiding dryer use when possible. “If you don’t have outdoor space, use an indoor folding rack – that’s what I do,” she says.
Though such solutions are seemingly obvious, reducing environmental pollution while improving energy efficiency and climate resilience, significant change will probably not come easily. “It’s difficult to change our lifestyles,” Moran says. “There’s a big gap between knowing what the solution is and doing it.”






