 CDC Cloth Mask Guidelines There is a lot of ignorance, misinformation, and conspiracy theories being spread about wearing masks during the COVID-19 pandemic, and I thought I would devote a post in my blog to set the record straight and provide references. Here I want to clarify that by “masks” I am referring to the regular loose fitting surgical or cloth masks that most people normally wear. For my post, I will describe the things people argue about masks and then reply to each one. When you buy the masks that many people use, it says on the box that they won’t protect the wearer from the coronavirus. Many doctors and scientists say that surgical or cloth masks worn by most people will not prevent them from getting the virus. This is an aspect of mask wearing that is not well understood by the general public and even by quite a few scientists, so I will try to explain. Masks got a bad rap back in 1918 when they were considered to have failed in controlling the spread of influenza, and a lot of this thinking still prevails in the scientific community today. However, it has been understood that the wearing of masks back then was often not performed adequately and was not coupled effectively with other measures. The type of masks most people wear will only provide limited protection from breathing in droplets (inward direction) emitted by unmasked people when they are talking, coughing, or sneezing within a short distance of the wearer (less than 6 feet). But that IS NOT the point of wearing these masks. The point of wearing these masks is to contribute to PROTECT OTHERS from the droplets emitted by the wearer when talking, coughing, or sneezing, in other words, to stop droplets in the outward direction (this is referred to as “source control”). There is abundant evidence that these masks can do this, not perfectly, but fairly well (1, 2, 3, 4, 5, 6, 7). You can find some fun demonstrations of the effectiveness of masks here, here, and here. Additionally, taking into account that we now know that many individuals with COVID-19 can transmit the virus even while they are presymptomatic or asymptomatic, mask wearing by the public is even more important to protect others. However, if others do not wear a mask in your presence, this defeats the purpose of wearing masks. The point of wearing a mask is to minimize the chance that the wearer will contaminate others. Nevertheless, it must be emphasized that the intention is for masks to be worn in addition to social distancing, hand washing, and avoiding or minimizing your exposure to crowded places. Doing ALL these greatly decreases your probability of catching the virus. The virus is tiny, it will not be stopped by face masks with large fabric holes like the ones most people wear. Wearing a cloth mask to stop the virus is like putting up a chain link fence to stop mosquitoes.
Yes it will be stopped, because viral particles are expelled forming part of liquid droplets, and the majority of these droplets are hundreds to thousands of times larger than the virus. The mask stops or deflects a significant proportion of these droplets. Cloth masks will trap all the germs like bacteria, viruses, and fungi you expel and then you will breathe them back in and this is bad for your health. That is kind of the point of wearing masks: to trap the germs! This is why you should wash cloth masks after you use them. You put on clean clothes before you begin your day, right? Well, also put on a clean mask. How hard is that? Wearing a mask will trap carbon dioxide and you will breathe back all that carbon dioxide which will decrease your oxygen levels and harm you. This has been demonstrated by performing carbon dioxide measurements inside the masks while people are wearing them. If you (wrongly) argue that it is impossible to trap the COVID-19 virus with a cloth mask because it is so small, then you can’t argue at the same time that the mask will trap carbon dioxide. Carbon dioxide is a gas. A molecule of carbon dioxide is hundreds of times smaller than the COVID-19 virus and tens of thousands of times smaller than the liquid droplets which contain the virus. The social media notion that masks trap carbon dioxide arose as a result of a video posted by a person who used a measuring device improperly and obtained bogus measurements. This notion is inaccurate as the space between the mask and the face is very small and makes a negligible contribution to the dead volume of the lungs. With each inhalation the gas in this space is replaced by gas from the outside. In any case, the appropriate measurement to perform is whether the oxygen levels in the blood decrease as a result of wearing a mask. A number of health care professionals have done this and posted the results on social media. Masks don’t decrease blood oxygen levels. In many Asian countries huge numbers of people have worn masks during the cold and flu season for decades without any such problem arising. The real purpose of a mask is to serve as a mind control device by a manipulative government that wants to roll back our freedoms and make us afraid and submissive. This is a conspiracy theory, and it is up to their proponents to present evidence that it is true. An alternative explanation is that our elected representatives are just following the best evidence and facts available as relayed to them by science. But the argument portraying masks as a mind control device can be made about virtually anything. Use of seat belts, stopping at traffic lights, following speed limits, using a cross walk to cross the street, and many other safety guidelines or laws can all be interpreted as things or designs dreamed up by the powers that be to control our lives and reduce us to sheep. If we accept this, then any government action that involves requesting a change in the behavior of the population can then be assigned a nefarious motive becoming part of a conspiracy. People have fought against masks before and now they are doing it again. We know to a certain extent why people are fighting face masks and promoting conspiracy theories about them even while coronavirus cases, hospitalizations, and deaths are on the rise. It is a combination of the anxiety and loss of control that a situation like COVID-19 produces, the politicization of the issue, and the distrust of government many individuals profess coupled with the erosion of the trust in science that has taken place in our society. However, as I’ve written before, reality can’t be compromised. The evidence so far indicates that masks, when coupled to social distancing and other measures, contribute to decrease the spread of COVID-19. It is our job as scientists to uphold these facts. Many people will not like this. However the point of science is not to win popularity contests but to discover and convey the truth. And we are going to keep on doing just that. The image from the Centers for Disease Control and Prevention is in the public domain.
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