Can face masks cause harmful levels of reduced oxygen?

CLAIM: Wearing face masks can cause harmful levels of reduced oxygen.

CONCLUSION: INACCURATE. Face masks have no impact on oxygen levels.

On social media, a posting repeats a claim that wearing a face mask led to a lack of sufficient oxygen and contributed to hospitalisation. The post is titled ‘FROM A HAIRDRESSER IN IRELAND’ and has been shared widely across Facebook. It does not specify the type of mask worn. 

Do face masks reduce oxygen?

The claim that face masks reduce oxygen has been circulating around the world since the beginning of the COVID-19 pandemic.

A search of the CoronaVirusFacts Alliance database for oxygen or hypoxia (a condition caused by lack of oxygen) shows over 40 scientifically fact-checked articles rebutting the claim that face masks reduce oxygen.

The WHO is categorical in their public advice, stating that the prolonged use of face masks does not lead to oxygen deficiency.

Doctors and nurses have also responded to the claims with practical demonstrations.

Irish GP, Dr Maitiú Ó Tuathail explains that oxygen can permeate through both cotton face coverings and surgical grade masks. Prof Keith Neal, an infectious disease expert, underlines that “[t]hin paper or cloth masks will not lead to hypoxia. Surgeons operate for hours wearing them. They don’t get these problems.”

Ó Tuathail made a video where he put six surgical masks on, one on top of the other, while he monitored his blood oxygen levels. The monitor showed that his oxygen levels stayed at 99% throughout the test. A Leeds doctor, Dr Hannah Barham-Brown, repeated the exercise wearing four face coverings (three fabric and one surgical mask), with the same result.

FactCheckNI has explained previously the important distinction between medical respirator masks and face coverings.

It is recommended by governments in the UK and Ireland, and the Northern Ireland Executive, that people wear face coverings—not respirator masks—in enclosed public spaces. Most commonly, fabric face coverings are recommended. In practice, many people have opted to wear light surgical style masks.

The CDC has indicated that N-95 respirator masks may sometimes result in a decrease in frequency and depth of breathing if worn for too long. However, these masks are only for use by medical professionals, and are not recommended for use by the general public

What about people with lung conditions?

The British Lung Foundation advises that “[w]earing a mask does not reduce a person’s oxygen supply,” even for those with lung conditions.

An American Thoracic Society study, which compared veterans with the lung disease COPD to healthy individuals, found that the effects of wearing a surgical mask “are minimal at most even in people with very severe lung impairment.”

Both sources suggest that although wearing a mask will be fine for most people with lung conditions, it may be uncomfortable for some, and can contribute to breathlessness, especially during exercise. But they underline that it is not medically dangerous to wear a mask. 

Despite there being no medical risk to oxygen levels from wearing a face mask, if wearing one causes severe distress to someone, under Northern Ireland guidelines, they are exempt. This could include people with asthma, COPD, emphysema and bronchitis.

What about hair salons?

On 10 August 2020 in Ireland, public health regulations made wearing face coverings mandatory in retail settings. This included customers in hair salons, and staff who were not behind a screen or more than 2m away from others. 

In Northern Ireland, wearing face coverings has been mandatory in enclosed public spaces where social distancing cannot be maintained since 10 August 2020. On 29 September 2020, detailed guidance for close contact services in Northern Ireland was issued, specifying that hairdressers must wear visors (or goggles) and a Type II face mask at work (not an N-95 or other respirator mask). A Type II face mask is typically a 3 layer pleated mask with ear loops or ties, such as a surgical mask. The Northern Ireland guidance says that while “Type II face masks are not PPE,” they will provide a barrier to minimise contamination when used properly.

In summary, there is no evidence that wearing a face mask reduces oxygen, or that a hairdresser in Ireland was hospitalised for this reason.


FactCheckNI is Northern Ireland’s first and only dedicated independent fact-checking service and a verified signatory to the International Fact-Checking Network’s Code of Principles. You can learn more about about FactCheckNI, our personnel, what our article verdicts mean, and how to submit a claim.