PROJECT HIGHLIGHT
Electronic clothes dryers may be a primary source of plastic microfiber pollution — the most common form of microplastic pollution globally and the dominant form of microplastic ingested by humans and wildlife. 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 shed from clothes and spread into the environment. Plastic microfibers are now the most ubiquitous form of microplastic pollution reported globally, as well as the dominant form of microplastic ingested by humans and wildlife. While many researchers once assumed that wastewater streams from washing machines were the major source, recent studies suggest that exhaust from clothes dryers may be a bigger culprit.
This project is investigating that hypothesis through residential and commercial sampling in the San Francisco Bay region. The research team has collected 33 dryer exhaust samples from 11 households, which are undergoing laboratory analysis for microplastic counts. Preliminary findings indicate that measurable amounts of lint are being vented outdoors from each laundry load. The team is also working to recruit laundromats to participate in the study, which will provide insights into commercial-scale emissions.
The researchers have tested dryer emissions with and without secondary filter devices. Mass measurements suggest lower emissions with secondary filters installed, although these results are not yet statistically significant. Further analysis using microplastic counts and spectroscopy identification is underway to provide more definitive conclusions. Based on the collected data, the research team will build a model to estimate the plastic loads reaching San Francisco Bay and compare results with previous estimates of total urban stormwater runoff loadings. While focused on the San Francisco Bay, the findings will be widely useful across North American urban settings where vented drying units are common.