Study: Cigarette filters are an underestimated source of microplastic pollution

BUFFALO, N.Y. –  It is well known that discarded cigarette butts release nicotine, heavy metals and other toxins into the environment, including natural water systems. Less understood, however, is what happens to the plastic-based filters that shed these chemicals.

A new study from the University at Buffalo examines this issue, with findings showing that one cigarette filter can release up to two dozen microfibers almost immediately upon contacting water. More than 100 additional microfibers may break free of the filter within 10 days depending on how the water is moving.

This quick release of cellulose acetate fibers – what most cigarette filters are made of – had not been precisely measured before, study authors say. This and other findings from the study build upon the evidence that cigarette butts –the most littered item worldwide – are a direct and underestimated source of microplastic pollution.

“Microfibers in natural waters have been primarily associated with laundry and clothing. This work shows that microfibers from littered cigarette filters cannot be ignored,” says the study’s corresponding author John D. Atkinson, Scott and Coleen Stevens Chair in Engineering Sustainability and associate professor in the UB Department of Civil, Structural and Environmental Engineering.

The findings were published the Journal of Hazardous Materials: Plastics. UB PhD student Ghazal Vasseghi is the study’s first author.

For the study, Atkinson and Vasseghi conducted a series of 10-day lab experiments. They placed cigarette butts in water under three conditions: still water (0 revolutions per minute, or rpm), moderately moving water (80 rpm) and more intense moving water (200 rpm).

The researchers found that when a cigarette filter initially contacts water, it releases about 24 microfibers within 20 seconds, regardless of water movement. After 10 days, they found that a single filter – which contains more than 10,000 microfibers – can release 63 to 144 microfibers, depending on water movement.

Using this data, the researchers estimated the prevalence of microplastic pollution from cigarette filters in New York State – the study was funded by the state Environmental Protection Fund, which is administered by the state Department of Environmental Conservation.

Under conservative estimates, they calculated that anywhere from 71 million to 1.4 billion cigarette butt microfibers are released into New York waters every day. Areas with large populations are hotspots.

“Direct release of pre-contaminated microfibers is unique – we typically consider microplastics problematic because of the chemicals they adsorb in the environment, but these are released with contamination. You get both physical pollution of the fibers and chemical pollution of everything that’s stuck to them,” Atkinson said. “In a way, this is a new ‘bad thing’ associated with cigarettes.”

These fibers are easy for wildlife to ingest and can block their digestion. Microfibers also function as sponges, attracting and carrying heavy metals, pathogens, and other pollutants, including PFAS, or “forever chemicals.”

The researchers point to several interventions and behavior change campaigns that could reduce the number of cigarette butt microfibers released into waters.

“Our work can inform strategic placement of receptacles for cigarette butts. Adding filters to collect cigarette butts in storm sewers could also be beneficial,” Atkinson says.