Plastic pollution: clothes dryers appear to be a main source of microplastic contamination in the environment
According to US Environmental Protection Agency (EPA), microfibers are the most common type of microplastic (pieces of plastic less than 5 mm in diameter) found in the environment. Researchers have detected microfibers in a range of ecosystems, from seashores and seabeds to remote areas in national parks – even in the snow of the Alps and the Arctic.
Scientists estimate that over 8 million tonnes of plastic enter the world’s oceans each year and while bottles, bags and straws are all well-known examples of plastic pollution, another major source is what we wear on our body.
Most garments are made from plastic-based materials such as polyester, rayon, nylon, and acrylic. During washing, friction causes synthetic clothes to shed tiny plastic fragments, or microfibers. Due to their small size, many fibers escape through the dryer vent pipe and are released into the air, both inside and out, which means humans can often directly inhale the particles.
It has been estimated that more than 900 microplastic particles could be ingested by a child each year through dust. In 2019, researchers from the University of Victoria in Canada found that the average person consumes between 74,000 and 120,000 microplastics per year – and double that if they regularly drink bottled water.
The latest research, published in the journal Environmental Science and Technology Letters January 12 will be “essential” to managing microfiber pollution, said Professor Leung, lead author of the study. The Guardian.
“Once we know the source, we can start controlling it using simple methods.”
In the study, polyester and cotton garments were tumble dried in separate cycles of 15 minutes. After measuring the number of microfibers released by the vent, the researchers estimated that between 90 and 120 million microfibers are produced and emitted into the environment by each dryer, each year. The results suggest that dryers are a source of microfiber air contamination, releasing between 433,128 and 561,810 microfibers during 15 minutes of use, depending on dryer capacity.
To date, most published research has focused on the generation of microfibers from washing machines – for example, a pair of jeans can release around 56,000 microfibers per wash. However, the researchers’ findings indicate that drying produces more airborne microfibers than washing.
“The average Canadian household does 219 loads of laundry per year. Here we have estimated that the average Canadian household could free up [90 to 120 million] microfibers from a dryer every year,” the study says.
“That is, a significant number of microfibers are released into the atmosphere, which could potentially be inhaled and ingested by humans and animals. Microfibers released from clothes dryers are therefore likely to represent a substantial contribution to microplastic contamination of the environment on a global scale.
“Microfibers could be ingested by organisms ranging from zooplankton to fish and birds and transferred through food webs.”
The researchers noted that while cotton microfibers released into the environment can be ingested by organisms, they are not as persistent as polyester microfibers. For the same drying time, cotton textiles produced more stable amounts of lint after drying, according to the study, regardless of the amount of textiles in the dryer.
To minimize the release of microfibers into the air, the researchers advised that a simple, technical filtration system could be developed and adopted as an effective means of controlling the pollution generated by household clothes dryers.
“It is possible to minimize the release of microfibers from clothes dryers by installing a simple and technical filtration device at the end of the emission pipeline,” the study states.
Professor Leung and his colleagues have already designed basic filters using 3D printing that prevent microplastics from being emitted from washing machines, and are currently designing a similar system for clothes dryers, The Guardian reports.
“Those [filter systems] effectively removes most microfibers from laundry,” he told the outlet.
However, it is not known where these fibers will end up when the filters are cleaned.
“We suggest that the particles be collected in a bag,” he added.
Whether or not filters become widely used in the near future, the fight against microfibers largely depends on the fashion industry shifting to more environmentally friendly fabrics.
“In China, the Public Environmental Audit Committee has turned its attention to transforming the garment industry to make it prosperous and sustainable. However, it is unrealistic to phase out plastic microfibers in the short term without the substitution of more environmentally friendly textiles,” the study says.
“It is essential to make better textiles and garments with more wear resistance, longer wear time and better environmental friendliness.”
In the meantime, a simple trick to combat microplastic pollution in your home is to wash clothes with fabric softeners. A study by the Italian National Research Council in 2020 found that the number of microfibers emitted can be reduced by almost a third when washing with fabric softener because it reduces friction between fibres.