Which appliance emits more fibers into the atmosphere? A washer or dryer? Previous research has shown that washer agitation loosens fibers from clothing that ultimately ends up in the environment. Now a study published in the journal Environmental Science & Technology Letters in early January 2022, and referenced by Treehugger in a recent post, shows that tumble dryers are even more guilty of releasing microfibers into the environment, particularly when clothes are dried at high temperatures. The authors of the study, “Microfibers Released into the Air from a Household Tumble Dryer,” wrote that because vented air is usually not treated, microfibers are emitted directly through a ventilation pipe connected to the dryer to ambient air, either indoor or outdoor…If dryers are not connected to a ventilation system, the released microfibers could be inhaled directly from the indoor air by humans.”
For the study, the researchers used 12 clothing items made from 100 percent polyester fabric and 10 items made from pure cotton. These were dried separately in several 15-minute cycles in a standard household tumble dryer. A “high-volume, total suspended particle air sampler” was placed at the end of the duct to collect all airborne particles, regardless of size. The collected fibers were transferred to sealed Petri dishes for subsequent examination.
The researchers estimated that over 110,000 microfibers are released from just one kilogram (2.2 pounds) of polyester clothing in a 15-minute dryer cycle. Since a dryer’s average capacity is 6 to 7 kilograms (13 to 15 pounds), the total number of polyester microfibers released in 15 minutes of drying a full load could be around 561,810 ± 102,156. That number is only slightly lower for cotton clothes, at 433,128 ± 70,878 microfibers per full load.
Dryers Worse Than Washing Machines
These high numbers reveal that dryers are worse than washing machines: “Regardless of whether the textiles are cotton or polyester, for 1 kg of textiles, a dryer can generate more microfibers than that generated by a washing machine.”
What does this study mean for hoteliers who primarily wash towels and linen? Researchers found that cotton material does not produce as many fibers as those items made from polyester. What if your towels or linens have blends of both polyester and cotton? Well, then you have more of a problem.
Researchers believe a filtration system, with filters of various mesh sizes, could be effective at removing microfibers from tumble dryers. If implemented, the key would be cleaning the filters regularly.
Do you go the extra mile to filter the water and air coming out of your washers and dryers? If so, I would love to learn more about it. I can be reached at firstname.lastname@example.org.