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Debunked: No, wearing a face mask does not 'disrupt pH levels' and increase cancer risk

A widely shared Facebook post incorrectly claims that wearing a mask causes people to breathe in their own carbon dioxide.


FACE MASKS OR coverings are now mandatory or recommended in various settings as part of efforts to curb the spread of Covid-19.

As the wearing of face masks has become more common, so too have social media posts criticising this fact and questioning the reasoning behind it.

One post being widely shared on social media this month claims claims that wearing a mask causes people to breathe in their own carbon dioxide (CO2), saying this converts into acid in a person’s bloodstream and disrupts their body’s pH levels.

The post states that diseases “cannot survive in an alkaline state; however, in a low oxygen/low pH (acidic) state, viruses, bacteria, yeast, mold, fungus, candida and cancer cells all thrive”.

Screenshot 2020-08-20 at 11.18.15 Facebook Facebook

Similar claims were made in a video that went viral earlier this year. The footage, shared thousands of times on Facebook, featured a woman, Danika Bueno, who identified herself as a nurse warning the public against continuously wearing face masks.

Bueno also states that wearing a mask leads to creating an “acidotic state” or pH imbalance in the blood as “rebreathing” your own CO2 creates “pH imbalance” in your blood.

These claims were discredited by medical experts at the time and debunked by AFP Fact Check back in June. However, the video was already viewed tens of thousands of times at that stage and the claims keep resurfacing.

In relation to the post being shared by Irish Facebook users in recent weeks, asked a doctor to explain why the claims are incorrect.

GP Maitiú Ó Tuathail noted that face coverings block Covid-19 droplets but they do not block either oxygen or carbon dioxide.

“Both oxygen and carbon dioxide molecules are tiny, thousands of times smaller that the droplets containing coronavirus that the face coverings are designed to stop. The oxygen and carbon dioxide won’t be trapped by any breathable material, whether a surgical face mask or cotton face covering.”

Ó Tuathail noted that extensive research has been done on this topic, well before the Covid-19 pandemic. As an example of how safe they are, he noted that surgeons “wear face masks for hours and hours on end, and have done for centuries”.

‘If you don’t like wearing a face covering, you really won’t like a ventilator’

Ó Tuathail said the misinformation being spread online about face masks and coverings is leading to “unnecessary fear amongst the public” and is “very unhelpful in the fight against Covid”.

He told us that he and other GPs are regularly asked by patients to write them letters exempting them from wearing face coverings on medical grounds.

“Face coverings may be uncomfortable to wear, as they do reduce the flow of air around your face, but they are not harmful and won’t reduce your oxygen levels or increase your carbon dioxide levels.

“As such, I have very frank conversations with my patients. Those seeking exemptions on medical grounds are those who stand to gain the most from wearing face coverings, as they are at higher risk of developing Covid, and being very ill from it if they do contract it.

“I keep it simple. If you don’t like wearing a face covering, then you really won’t like wearing a ventilator. I can’t be any more blunt than that.”

shutterstock_1683544594 File photo Shutterstock / kovop58 Shutterstock / kovop58 / kovop58

The HSE also said the claims are inaccurate. A spokesperson told that wearing a face covering reduces the spread of Covid-19 in the community.

“It helps to reduce the spread of respiratory droplets from people infected with coronavirus. This helps to stop people who are not aware they have the virus from spreading.”

The spokesperson noted that face coverings are not recommended for children under the age of 13 “because young children may not follow the advice about wearing a mask correctly”.

“They may also not understand the importance of avoiding touching it. However, children under 13 should wear a mask if their doctor or healthcare worker advises this.

“For example, some children may be advised to do this when attending a hospital clinic. You do not have to wear a face covering if you have an illness or impairment that would make wearing or removing a face covering upsetting or uncomfortable.”

The spokesperson added that the HSE “false or misleading health information is a big problem”.

“It is really important to question where information has come from. Take your time to check it out against reliable sources of information. This will help you decide if you can trust the advice.

“We can help to stop the spread of misinformation by learning how to spot it, not believing it and not sharing it with others.”

More information on face masks can be read here.


There is a lot of false news and scaremongering being spread in Ireland at the moment about coronavirus. Here are some practical ways for you to assess whether the messages that you’re seeing – especially on WhatsApp – are true or not.


Look at where it’s coming from. Is it someone you know? Do they have a source for the information (e.g. the HSE website) or are they just saying that the information comes from someone they know? A lot of the false news being spread right now is from people claiming that messages from ‘a friend’ of theirs. Have a look yourself – do a quick Google search and see if the information is being reported elsewhere. 

Secondly, get the whole story, not just a headline. A lot of these messages have got vague information (“all the doctors at this hospital are panicking”) and don’t mention specific details. This is often – but not always a sign – that it may not be accurate. 

Finally, see how you feel after reading it. A lot of these false messages are designed to make people feel panicked. They’re deliberately manipulating your feelings to make you more likely to share it. If you feel panicked after reading something, check it out and see if it really is true.’s FactCheck is a signatory to the International Fact-Checking Network’s Code of Principles. You can read it here. For information on how FactCheck works, what the verdicts mean, and how you can take part, check out our Reader’s Guide here. You can read about the team of editors and reporters who work on the factchecks here

Have you gotten a message on WhatsApp or Facebook or Twitter about coronavirus that you’re not sure about and want us to check it out? Message or mail us and we’ll look into debunking it. WhatsApp: 085 221 4696 or Email:

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