A screenshot of a 2022 article about microplastics being found in the lungs has been shared by social media users to suggest facial coverings worn during the COVID-19 pandemic are to blame. Experts told Reuters that while it is true that some masks could shed microplastics, it is unknown whether there is a risk posed to humans. Moreover, the article being cited does not mentioned face masks and one of the studies mentioned began data collection prior to the pandemic. Some face coverings can help reduce the inhalation of non-mask microplastics, and it is widely agreed that the risks outweigh the benefits of protecting people against COVID-19.

One Facebook profile named ‘Don’t Trust Government’ posted a composite image (here) which shows a screenshot of an Amazon listing for “3-ply face masks… made with polypropylene” (here) and another screenshot of an April 6, 2022, The Guardian news article headlined: “Microplastics found deep in lungs of living people for first time” (here). The news article makes no mention of face masks but does address the scale of microplastic pollution and the potential danger this poses to human health.

The Facebook post has been shared more than 400 times and its caption reads: “Probably just a coincidence.”

Similar posts on the platform can be found (here, here, here, here, here and here) and on Twitter (here and here), where together they have been shared more than 20,000 times.

Microplastics are created when bigger pieces of plastic litter break up over time. They are less than five millimeters long and can be found in the air, food, drinking water and Arctic ice. Scientists are increasingly worried they may pose a risk to human health and marine life, though there is no consensus yet on the issue (here and here).

Microplastics found in people’s lungs could come from several sources, according to Dr Miranda Loh of the Institute of Occupational Medicine (IOM) (here).

“Synthetic fabrics, such as clothing and household textiles or other plastic products, can shed similar fibres and all of these can be inhaled by people,” she told Reuters via email.

Dr Loh then noted that the 2022 Jenner et al. study (here) quoted in the article by The Guardian did not make it clear whether the people involved in the research were wearing masks or when their lung tissue samples were taken.

She added: “They could have been taken before mask wearing became the norm. A Brazilian research article, which did a similar study (here) and was also noted in The Guardian, began data collection in 2019 before the COVID-19 pandemic. I am sure that we have been breathing in microplastics long before COVID and mask wearing.”

Polypropylene, the microplastic mentioned in the Facebook post, is a “type of plastic molecule used in many products, including textiles,” Dr Loh told Reuters.

“Non-woven polypropylene is useful for face masks because the arrangement of the fibres is random (unlike a woven material), so this makes it more effective at trapping particles... the material has good filtration properties, and is also breathable,” she explained.

Although there is “a potential for irritation, as with anything you inhale” and “exposure to very high levels could potentially affect respiratory symptoms, there are not many studies on this, especially in people”.

Dr Loh added: “I don’t think we know much about how much people might inhale from wearing masks and whether this is enough to cause any problems.”

Professor Chris Cappa of the University of California, Davis (here), told Reuters via email that “some face coverings can release small particles (of microplastics) when worn” by “rubbing between the face and the mask”. However, this is dependent on the type of mask.

He said: “Our observations show that cotton cloth masks tend to release the most particles. Some fibres do come off polyester cloth masks, although a lot less than those that come off cotton masks. In contrast, essentially no particles are released from surgical masks or N95s, which are made from polypropylene. For surgical masks and N95s, this is true even with vigorous and intentional rubbing, substantially more than occurs during normal wearing.”

However, based on the results of the 2022 Jenner et al. study referenced in the article by The Guardian, Prof. Cappa added that he has “no concerns about microplastics getting into people’s lungs from wearing surgical masks, N95s, or really any mask”.

“I would be more concerned about small cotton fibres, although I’m ultimately more concerned about catching a deadly disease,” he concluded.

DANGERS OF MASK MICROPLASTICS ‘UNKNOWN’

Lastly, Professor Dick Vethaak of independent research institute Deltares and Vrije Universiteit Amsterdam (here), told Reuters via email that it is “unknown how much face mask plastic particles contribute to the total (microplastic) particle exposure and particle load in our body”.

But, he added, a 2021 study by Li et al. (here) indicated that “wearing masks generally leads to lower gross microplastic inhalation risk in the long term” as it “considerably reduces the inhalation risk of particles, even when they are worn continuously for 720 hours”.

Prof. Vethaak also said that masks “generally block the transmission of micro and even nano-sized particles” into people’s lungs, “but not completely”.

He concluded: “The usage of masks reduces the risk of inhaling particles (such as plastic particles, viruses, and other unknown particles). This is critical in the event of a pandemic. Despite the fact that they may contribute to certain microplastics inhalation, it is a minimal issue compared to protecting humans from COVID-19.”

All three experts agreed: that face coverings could shed microplastics into people’s lungs, especially if they are excessively reused; there are numerous sources of microplastics, not just masks; it is unknown whether the quantity of microplastics produced by masks is dangerous; and that some masks can prevent microplastics from getting into people’s lungs.

A similar fact check on the subject can be found here.

Missing context. Microplastics from masks can shed into people’s lungs, but how dangerous this can be is unknown. Masks can also help lower the number of microplastics an individual inhales.

This article was produced by the Reuters Fact Check team. Read more about our fact-checking work here.

Our Standards: The Thomson Reuters Trust Principles.

All quotes delayed a minimum of 15 minutes. See here for a complete list of exchanges and delays.