The surge in the use of disposable face masks during the Covid pandemic has left a chemical timebomb that could harm humans, animals and the environment, research suggests.
Millions of tonnes of plastic face masks created to protect people from the spread of the virus are now breaking down, releasing microplastics and chemical additives including endocrine disruptors, the research found.
As a result, the very equipment whose use was intended to protect people during the pandemic now poses a risk to the health of people and planet, potentially for generations.
“This study has underlined the urgent need to rethink how we produce, use and dispose of face masks,” said Anna Bogush of Coventry University’s Centre for Agroecology, Water and Resilience, the lead author of the study.
It has been estimated that during the height of the coronavirus pandemic 129bn disposable face masks, mostly made from polypropylene and other plastics, were being used every month around the world.
With no recycling stream, most ended up either in landfill or littered in streets, parks, beaches, waterways and rural areas, where they have now begun to degrade. Recent research has reported a significant presence of disposable face masks in both terrestrial and aquatic environments.
Bogush and her co-author, Ivan Kourtchev, set out to determine how many microplastic particles were released from face masks simply sitting in water, without moving at all.
They left newly bought masks of several different kinds for 24 hours in flasks containing 150ml of purified water, then filtered the liquid through a membrane to see what came out.
Every mask examined by Bogush and Kourtchev leached microplastics, but it was the FFP2 and FFP3 masks – marketed as the gold-standard protection against the transmission of the virus – that leached the most, releasing four to six times as many.
“The particle sizes of MPs [microplastics] varied greatly, ranging from around 10μm–2,082μm, but microplastic particles below 100μm were predominant in the water leachates,” they wrote in their paper, published in the journal Environmental Pollution.
And they made an even more worrying discovery. Subsequent chemical analysis of the leachate found medical masks also released bisphenol B, an endocrine-disrupting chemical that acts like oestrogen when absorbed into the bodies of humans and animals.
Taking into account the total amount of single-use face masks produced during the height of the pandemic, the researchers estimated they led to the release of 128-214kg of bisphenol B into the environment.
Bogush said: “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. As we move forward, it’s vital that we raise awareness of these risks, support the development of more sustainable alternatives and make informed choices to protect our health and the environment.”
• This article was amended on 9 September 2025. An earlier version said billions of tonnes of plastic face masks were breaking down; this should have said millions of tonnes.
