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Covid masks may expose users to harmful chemicals

A recent study published in the journal Ecotoxicology and Environmental Safety and on the National Institutes of Health (NIH) website suggests that wearing N95 Covid masks, specifically KF94 medical masks, may expose individuals to a dangerous level of toxic volatile organic compounds (TVOCs). 

Researchers from Jeonbuk National University in South Korea analyzed two types of disposable medical-grade masks and several reusable cotton masks. They found that the chemicals released by these masks had eight times the recommended safety limit of TVOCs.

“An increase in the concentration of environmental particulate matter and the spread of the COVID-19 virus have dramatically increased our time spent wearing masks. If harmful chemicals are released from these masks, there may be harmful effects on human health,” wrote the study authors. 

TVOC exposure 

Exposure to TVOCs has been associated with health issues like headaches and nausea, and prolonged and repeated exposure has been linked to organ damage and even cancer. “It is clear that particular attention must be paid to the VOCs associated with the use of KF94 [medical] masks and their effects on human health,” the researchers stated. 

However, they also noted that “exposure can be significantly reduced if a mask is opened and left to sit for at least 30 minutes,” suggesting that the packaging of these masks could play a role in the chemical levels they contain.


The study did not measure the effects of people actually wearing the masks, leading Dr. Stuart Fischer, an internal medicine physician in New York, to caution against drawing strong conclusions from the study. 

Dr. Fischer told that there is increasing evidence showing the drawbacks of mask-wearing, and “there seems to be diminishing returns on the need for masks.”

Focus of the study

TVOCs are a large group of odorous chemicals released by cleaning and beauty products, burning fuel, cooking, aerosol sprays, disinfectants, moth repellents, air fresheners, automotive products, building materials, office equipment, permanent markers, correction fluids, carbonless copy paper, and craft materials including glues and adhesives. 

These chemicals can irritate the eyes, nose, and throat, cause difficulty breathing and nausea, and damage the central nervous system and organs like the liver, according to the American Lung Association (ALA). Some are even considered human carcinogens.

For the investigation, 14 disposable and cloth masks purchased online were tested for TVOCs. The disposable masks were KFAD and KF94 models made from thermoplastics polypropylene and polyurethane nylon, popular in South Korea, whereas KN95s are more popular in the US. 

The cloth masks were made from cotton, ramie (a vegetable fiber), and polyurethane. 

What the researchers learned

The researchers found that the disposable masks contained up to 14 times the TVOCs contained in cotton masks, exceeding the Environmental Protection Agency (EPA) recommended limit of 0.5 parts per million in indoor air.

The experts specifically flagged the chemicals dimethylacetamide (DMAc) and dimethylformamide (DMF) for being linked to liver and reproductive damage. They acknowledged that the sample size was small and that they did not test several other popular disposable masks like KN95s. 

Study implications 

The study builds off previous research suggesting that mask-wearing could cause more harm than good, including a study by the Cochrane Institute that suggested face masks made “little to no difference” in Covid infections and deaths.

Dr. Fischer told Daily Mail that “it is indeed possible that certain masks have side effects, just as certain helpful medications (anti-histamines, psychotropic drugs, antibiotics) have side effects. Almost everything in healthcare has a benefit/side effect profile.” 

Dr. Fischer emphasized the need for policies that do not fracture society while providing minimal protection as Covid is unlikely to disappear anytime soon.

Covid variant BA.2.86

The study’s findings may have new relevance as the Covid variant BA.2.86 spreads, potentially dodging the body’s immune defenses from prior infections or vaccinations. 

Authorities consider BA.2.86 part of the Omicron variant family, but the World Health Organization (WHO) has indicated this could change if the strain spreads more widely. 

With Covid cases climbing in the US and businesses and schools reinstating mask mandates, the study’s findings could make mask mandates ineffective. 

“I think following the general recommendations might be helpful, but it’s not clear yet if we need the sweeping edicts of three years ago,” Dr. Fischer told Daily Mail.

“Extreme fears about the lethality of Covid may have led to decisions that were counterproductive.”

“Covid won’t be going away for a long time, if ever. We desperately need policies that do not fracture our society while providing minimal protection.”

The NIH said: “Inclusion in an NLM database does not imply endorsement of, or agreement with, the contents by NLM or the National Institutes of Health.”


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