Does exhaled carbon dioxide in a mask cause any side effects?
Does exhaled carbon dioxide in a mask cause any side effects?
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25 April 2022: Public health authorities such as the U.S. Centers for Disease Control and Prevention (CDC) and the World Health Organization (WHO) continue to recommend the community-wide use of masks as a safe and effective measure to reduce the spread of SARS-CoV-2. Studies have continued to show over the course of the pandemic that under most circumstances, wearing a face mask (whether a cloth mask, surgical mask, or respirator) leads to minimal changes in oxygen and carbon dioxide levels, and has no significant negative health effects.
It takes a very high level of carbon dioxide to cause health problems. These dangerously high levels of carbon dioxide do not build up with these masks when they are worn appropriately and for regular periods of time because the molecules are very tiny and easily pass through the mask materials.
Some data does suggest that certain types of very protective masks worn during very strenuous activity can result in some health challenges. For instance, some studies have found that N95 respirators in particular, when worn over very long time periods and when used during very high intensity work, can produce negative effects like headaches, difficulty breathing, and exhaustion. This situation is very uncommon for most people in day-to-day situations.
We previously reported in 2020 that for people diagnosed with illnesses such as COPD, emphysema, and obesity, and in heavy smokers, the consistent use of N95-like masks over long periods of time could cause some build-up of carbon dioxide levels in the body. This is not the case except in extreme cases such as very strenuous exercise. However, some people with severe respiratory conditions like asthma may not feel they can breathe adequately while wearing a mask. These individuals should try to stay out of public settings as much as possible where masks are needed.
25 April 2022: Public health authorities such as the U.S. Centers for Disease Control and Prevention (CDC) and the World Health Organization (WHO) continue to recommend the community-wide use of masks as a safe and effective measure to reduce the spread of SARS-CoV-2. Studies have continued to show over the course of the pandemic that under most circumstances, wearing a face mask (whether a cloth mask, surgical mask, or respirator) leads to minimal changes in oxygen and carbon dioxide levels, and has no significant negative health effects.
It takes a very high level of carbon dioxide to cause health problems. These dangerously high levels of carbon dioxide do not build up with these masks when they are worn appropriately and for regular periods of time because the molecules are very tiny and easily pass through the mask materials.
Some data does suggest that certain types of very protective masks worn during very strenuous activity can result in some health challenges. For instance, some studies have found that N95 respirators in particular, when worn over very long time periods and when used during very high intensity work, can produce negative effects like headaches, difficulty breathing, and exhaustion. This situation is very uncommon for most people in day-to-day situations.
We previously reported in 2020 that for people diagnosed with illnesses such as COPD, emphysema, and obesity, and in heavy smokers, the consistent use of N95-like masks over long periods of time could cause some build-up of carbon dioxide levels in the body. This is not the case except in extreme cases such as very strenuous exercise. However, some people with severe respiratory conditions like asthma may not feel they can breathe adequately while wearing a mask. These individuals should try to stay out of public settings as much as possible where masks are needed.
Exhaled carbon dioxide caused by the use of face masks, including the N95 mask, has not been shown to cause carbon dioxide toxicity or lack of adequate oxygen in healthy people. Because the masks we make and purchase, and even the airtight medical masks listed above, are designed for constant breathing, the risks of any side effects are low. Again, for people diagnosed with illnesses such as COPD, emphysema, and obesity, and in heavy smokers, the consistent use of N95-like masks over long periods of time could cause some build-up of carbon dioxide levels in the body. If people in this group are experiencing these side effects, they should speak to their doctor.
Exhaled carbon dioxide caused by the use of face masks, including the N95 mask, has not been shown to cause carbon dioxide toxicity or lack of adequate oxygen in healthy people. Because the masks we make and purchase, and even the airtight medical masks listed above, are designed for constant breathing, the risks of any side effects are low. Again, for people diagnosed with illnesses such as COPD, emphysema, and obesity, and in heavy smokers, the consistent use of N95-like masks over long periods of time could cause some build-up of carbon dioxide levels in the body. If people in this group are experiencing these side effects, they should speak to their doctor.
Publication
What our experts say
Exhaled carbon dioxide caused by the use of face masks, including the N95 mask, has not been shown to cause carbon dioxide toxicity or lack of adequate oxygen in healthy people. Because the masks we make and purchase, and even the airtight medical masks, are designed for constant breathing, the risks of any side effects are low. For people diagnosed with illnesses such as COPD, emphysema, and obesity, and in heavy smokers, the consistent use of N95-like masks over long periods of time could cause some build-up of carbon dioxide levels in the body. If people in this group are experiencing these side effects, they should speak to their doctor.
Exhaled carbon dioxide caused by the use of face masks, including the N95 mask, has not been shown to cause carbon dioxide toxicity or lack of adequate oxygen in healthy people. Because the masks we make and purchase, and even the airtight medical masks, are designed for constant breathing, the risks of any side effects are low. For people diagnosed with illnesses such as COPD, emphysema, and obesity, and in heavy smokers, the consistent use of N95-like masks over long periods of time could cause some build-up of carbon dioxide levels in the body. If people in this group are experiencing these side effects, they should speak to their doctor.
Context and background
The claim that the prolonged use of face masks can cause carbon dioxide intoxication, dizziness, or other health challenges is not grounded in science. In fact, healthcare workers often wear masks for long hours in the hospital. There is no evidence that surgical masks or cloth masks cause significant build-up of carbon dioxide. This information has been primarily circulating on social media among individuals or communities resistant to mask-wearing in general. While masks are restrictive and can feel like they impede air flow, properly designed masks do allow air flow by design, and the feeling of inconvenience or minor discomfort does not equate to health risks such as a build-up of carbon dioxide. Inhaling high amounts of carbon dioxide can be dangerous and lead to hypercapnia (carbon dioxide toxicity), but is extremely unlikely to happen as a result of wearing a mask.
There is some evidence that prolonged use of N95 masks in wearers with particularly severe health conditions, such as lung disease, could cause some build-up of carbon dioxide in the body. However, these cases are rare, and the use of N95 masks is not recommended for the general public in order to reserve them for frontline workers who are at higher risk of exposure to the virus.
The claim that the prolonged use of face masks can cause carbon dioxide intoxication, dizziness, or other health challenges is not grounded in science. In fact, healthcare workers often wear masks for long hours in the hospital. There is no evidence that surgical masks or cloth masks cause significant build-up of carbon dioxide. This information has been primarily circulating on social media among individuals or communities resistant to mask-wearing in general. While masks are restrictive and can feel like they impede air flow, properly designed masks do allow air flow by design, and the feeling of inconvenience or minor discomfort does not equate to health risks such as a build-up of carbon dioxide. Inhaling high amounts of carbon dioxide can be dangerous and lead to hypercapnia (carbon dioxide toxicity), but is extremely unlikely to happen as a result of wearing a mask.
There is some evidence that prolonged use of N95 masks in wearers with particularly severe health conditions, such as lung disease, could cause some build-up of carbon dioxide in the body. However, these cases are rare, and the use of N95 masks is not recommended for the general public in order to reserve them for frontline workers who are at higher risk of exposure to the virus.
Resources
- Carbon dioxide increases with face masks but remains below short-term NIOSH limits (BMC Infectious Diseases)
- What do masks mask? A study on transdermal CO2 monitoring (Elsevier Public Health Emergency Collection)
- Is a Mask That Covers the Mouth and Nose Free from Undesirable Side Effects in Everyday Use and Free of Potential Hazards? (International Journal of Environmental Health and Public Health)
- The effects of wearing facemasks on oxygenation and ventilation at rest and during physical activity (PLOS ONE)
- Effect of Face Masks on Gas Exchange in Healthy Persons and Patients with Chronic Obstructive Pulmonary Disease (Annals of the American Thoracic Society)
- Potential Adverse Health Effects of Mask Wearing (Science Brief: Community Use of Masks to Control the Spread of SARS-CoV-2 | CDC)
- Fact Check-COVID-19 face masks do not trap dangerous levels of carbon dioxide (Reuters)
- Fact Check-Masks do not expose children to dangerous levels of carbon dioxide (Reuters)
- When and how to use masks (who.int)
- Partly false claim: Continually wearing a mask causes hypercapnia (Reuters)
- Fact check: Wearing a face mask will not cause hypoxia, hypoxemia or hypercapnia (USA Today)
- This Myth About Carbon Dioxide And Masks Is Similar To A Debunked Claim About Climate Change (Forbes)
- Carbon dioxide increases with face masks but remains below short-term NIOSH limits (BMC Infectious Diseases)
- What do masks mask? A study on transdermal CO2 monitoring (Elsevier Public Health Emergency Collection)
- Is a Mask That Covers the Mouth and Nose Free from Undesirable Side Effects in Everyday Use and Free of Potential Hazards? (International Journal of Environmental Health and Public Health)
- The effects of wearing facemasks on oxygenation and ventilation at rest and during physical activity (PLOS ONE)
- Effect of Face Masks on Gas Exchange in Healthy Persons and Patients with Chronic Obstructive Pulmonary Disease (Annals of the American Thoracic Society)
- Potential Adverse Health Effects of Mask Wearing (Science Brief: Community Use of Masks to Control the Spread of SARS-CoV-2 | CDC)
- Fact Check-COVID-19 face masks do not trap dangerous levels of carbon dioxide (Reuters)
- Fact Check-Masks do not expose children to dangerous levels of carbon dioxide (Reuters)
- When and how to use masks (who.int)
- Partly false claim: Continually wearing a mask causes hypercapnia (Reuters)
- Fact check: Wearing a face mask will not cause hypoxia, hypoxemia or hypercapnia (USA Today)
- This Myth About Carbon Dioxide And Masks Is Similar To A Debunked Claim About Climate Change (Forbes)
