Science

Dryer Vents Blow Hot Air & Microplastics

by | Nov 18, 2021

clothes flapping on a laundry line in Germany by Michael Gabler

Wind and solar power dry this laundry in Germany. Photo: Michael Gabler

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

Seeking Friends for the End of the World

Could making friends with your neighbors be the secret to climate resilience? “All my homies are locally-sourced, non-GMO and gluten-free,” writes Maylin Tu of Los Angeles.

Refreshing Santa Clara County Rivers

Santa Clara’s National River Cleanup Day brought together 596 volunteers and resulted in over 25,000 pounds of trash collected. “It was one of the first times since the start of the COVID-19 pandemic, when we could actually organize group cleanups,” says Valley Water’s Nick Ingram

Chasing the Fireline

In California, climate change has has left a collection of wildfire hazard zone maps, published 15 years ago, out of date.

Cruising the San Pablo Spine: Video

Hop on a speeding bicycle with photographer Lonny Meyer as he travels the urban artery that is San Pablo Avenue and visits green infrastructure installations.

Overhauling Insurance for the New Normal

In the era of global warming, an invisible force, as primal as atmospheric chemistry, is coming to bear on human pocketbooks. Even if you don’t believe in climate change, insurance companies do.

Tears for Trees

I’ve watched an army of white trucks topped with cranes and chippers remove the oaks, redwoods, bays and manzanitas from around the power lines on our mountain in Napa. PG&E is felling a million trees per year and spending over a billion to do it.

National Toolkit Offers Steps & Metrics

The Resilience Metrics website is like a food-for-thought buffet for project planners. This toolkit offers a set of questions designed to get a project on track and to help participants measure performance.

Coast Leaders Talk Graceful Withdrawal

In two brief audio interviews, KneeDeep Times asks the Coastal Conservancy’s Amy Hutzel and the Coastal Commission’s Mary Matella for their perspective on planned withdrawal from sea level rise and the crumbling coast.

Pricing Climate Risk

To get the basics of pricing the risks of climate change, you could do worse than to talk to Dag Lohmann. He knows just how much creeping climate change is changing insurance arithmetic.

Photo: Ariel Okamoto

Dryer vent in San Francisco home.

Photo: Ariel Rubissow Okamoto

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.”

About The Author

Alastair Bland

a native to San Francisco, is a freelance journalist who writes about California water policy, rivers and salmon, marine conservation and climate change. His work has appeared at NPR.org, Smithsonian.com, Yale Environment 360, The Atlantic and Hakai Magazine, among other outlets.