PROJECT HIGHLIGHT
Electronic clothes dryers may be a primary source of plastic microfiber pollution — which constitutes the most common form of microplastic pollution globally and is the dominant form of microplastic ingested by humans and wildlife. By examining dryers in various settings in the San Francisco Bay Region, this project will provide the first estimates of real-world dryer microplastic emission rates and assess whether secondary filters offer a viable solution for reducing pollution.
PROJECT SUMMARY
Modern textiles often include plastic fibers, which as they're shed from the clothes can spread into the environment. Now plastic microfibers are the most ubiquitous form of microplastic pollution reported globally, as well as the dominant form of microplastic ingested by humans and wildlife. But precisely how these fibers reach the environment is not clear. Many researchers once assumed that wastewater streams from clothes washing machines were the major source, but recent studies suggest that exhaust from clothes dryers may be a bigger culprit.
This ongoing project is investigating that hypothesis through a combination of residential and commercial sampling. To date, the research team has collected 33 dryer exhaust samples from 11 households, which are currently undergoing laboratory analysis for microplastic counts. The team is also in the process of recruiting laundromats to participate in the study, which will provide insights into commercial-scale emissions.
Initial testing of secondary filters on dryer vents has shown lower emissions by mass compared to unfiltered vents, though results are not statistically significant. Further analysis using microplastic counts and spectroscopy identification is underway to better characterize these differences.
Based on the collected data, the research team will build a model to estimate the plastic loads reaching San Francisco Bay. The results will be compared with previous estimates of total urban stormwater runoff loadings of microplastics to the bay so as to reveal the relative importance of dryer emissions. While focused on the San Francisco Bay, the findings will be widely useful across North American urban settings, where vented drying units are common.