Study finds disposable Covid masks shed microplastics and chemicals that may persist in people and the environment

A study by researchers in the United Kingdom found that disposable face masks purchased for protection during the Covid‑19 pandemic can release microplastic particles and chemical additives into water even if they have not been worn, raising concerns about a persistent environmental and human health burden from single‑use masks.

Scientists at Coventry University placed newly bought surgical masks and filtering disposable masks in purified water and left them undisturbed for 24 hours, then analyzed the liquid for material and chemical release. The team reported that masks shed polypropylene and other plastics — including polyester, nylon and PVC — and that masks with filters released three to four times more microplastic particles than standard surgical masks.

The Coventry researchers also detected chemical additives leaching from the masks, notably bisphenol B, an endocrine disruptor. Taking into account estimates of the total number of single‑use masks produced during the pandemic, the team estimated that discarded masks could have released roughly 128 to 214 kilograms (282 to 472 pounds) of bisphenol B into the environment.

The findings were published in Environmental Pollution and underscore how a surge in single‑use mask production and disposal may have long‑term consequences for ecosystems and human health. Microplastics are microscopic fragments of plastic that can infiltrate food, water and air, enter the human body, circulate in the bloodstream and accumulate in organs. Studies have linked microplastic exposure and certain plastic‑derived chemicals to respiratory problems, changes in the gut microbiome, blood vessel damage, reduced fertility, and increased risks for cardiovascular disease and neurological disorders.

The scale of mask disposal during the pandemic was immense. One widely cited estimate, based on population and assumed mask acceptance rates, suggested about 1.2 trillion disposable masks were introduced to the environment globally between December 2019 and May 2021. Other estimates put monthly global usage at the pandemic’s height at roughly 129 billion masks. Regionally, a 2021 analysis found Asia used an estimated 1.8 billion masks at the height of the pandemic compared with 244 million in the United States; some reports at the time estimated China discarded more than 500 million masks and shields a day. In the United States, federal distribution programs supplied hundreds of millions of masks early in the response.

The Coventry team warned that most single‑use masks have ended up in landfills or as litter on streets, parks and beaches, where mechanical and environmental degradation can produce and release microplastics and associated chemicals into soils, waterways and marine systems. A 2024 study in the Journal of Hazardous Materials estimated that microplastics released from face masks could account for about 3 percent of marine microplastic emissions, while also noting that masks remained an important protective tool during viral outbreaks.

Dr. Anna Bogush, an associate professor at Coventry’s Centre for Agroecology, Water and Resilience and a co‑author of the study, said the research highlights an urgent need to rethink how masks are produced, used and disposed of. "We can't ignore the environmental cost of single‑use masks, especially when we know that the microplastics and chemicals they release can negatively affect both people and ecosystems," she said.

Laboratory methods used in the study involved immersing each mask sample in 150 milliliters (about five fluid ounces) of purified water for 24 hours and then analyzing the water for fibers and chemical residues. The authors cautioned that while laboratory conditions cannot capture every environmental pathway and degradation process, the experiments demonstrate that even new masks can be sources of microplastic and chemical release when exposed to water.

Researchers and public health authorities have emphasized that masks played a critical role in reducing virus transmission during the pandemic, and the Coventry authors stopped short of recommending that individuals forgo masks when they are indicated for infection control. Instead, the study calls for greater awareness of disposal impacts, promotion of proper waste management, and the development and adoption of more sustainable alternatives to conventional single‑use masks.

Governments, manufacturers and waste managers face a policy challenge balancing immediate public health protections and longer‑term environmental risks, the researchers said. Possible responses include increased collection and safe disposal programs for personal protective equipment, standards for biodegradable or less chemically loaded mask materials, and guidance for safe reuse where feasible. The authors also urged further research to quantify how much microplastic and chemical exposure from masks contributes to human body burdens relative to other sources such as packaging, textiles and tires.

The study adds to a growing body of evidence that microplastics are pervasive in modern environments and human bodies. Investigators continue to examine pathways and health impacts, and to evaluate mitigation strategies that preserve infection control benefits while reducing persistent contamination from single‑use products.