A participatory science approach to quantify microfiber emissions from clothes dryers

Studies have shown that washing and drying clothes contribute microfiber contamination to the environment. However, there is a lack of data from clothes dryers under normal household use. To begin to address this data gap, we recruited participatory volunteer scientists to install a mesh on their dryer vents for 3 weeks. During that time, the volunteers used a mobile phone application to record information about what was dried. The material accumulated on the mesh was analyzed for material composition. The results showed that the items dried were primarily composed of cotton, followed by polyester. The textile-derived microfibers on the mesh were primarily cellulose, followed by polyethylene terephthalate/polyester and other plastics. When we compared the microfibers on the mesh with the textiles dried, we found that the relative percentage of cellulosic microfibers on the mesh was higher than the percentage of cellulosic textiles dried. This suggests cellulosic textiles potentially released more microfibers than synthetic textiles. On average, 138 mg of material was emitted per dryer load. When scaled to the number of electric clothes dryers in the United States and the average number of dryer loads per household per year, we estimated dryers release approximately 3543.6 metric tons of microfibers per year in the United States. The results indicate that clothes dryers are potentially a significant source of cellulosic and synthetic microfibers being released into the air, and steps should be taken to reduce these emissions. The methods outlined here can be applied to other studies to assess microfiber emissions from dryers under normal household use.