Everything You Always Wanted to Know About Masks, and the Deadly Falsehoods Surrounding Them

Sep 14, 2021 by

“Everything You Always Wanted to Know About Masks, and the Deadly Falsehoods Surrounding Them”

By James D. Agresti



In a terse essay titled “Science and Dictatorship,” Albert Einstein warned that “Science can flourish only in an atmosphere of free speech.” And on his deathbed, Einstein cautioned, “Whoever is careless with the truth in small matters cannot be trusted in important affairs.”

With reckless disregard for both of those principles, powerful government officials and big tech executives have corrupted or suppressed the central scientific facts about face masks. The impacts of this extend far beyond the issue of masks and have caused widespread harm and countless deaths.

Despite the fog of contradictory claims and changing government guidelines, dozens of scientific journals have published consistent data that establish these facts:

  • Covid-19 is mainly spread by microscopic aerosols generated by breathing, talking, sneezing, and coughing. The vast bulk of these infectious aerosols easily penetrate common masks because 90% of the aerosols are less than 1/17th the size of pores in the finest surgical masks, and less than 1/80th the size of pores in the finest cloth masks.
  • Aerosols are light enough to stay airborne for minutes or hours, and hence, they also travel freely through gaps around the edges of cloth and surgical masks.
  • Governments enacted mask mandates based on the false assumption that C-19 is mainly transmitted by large droplets generated by coughing, sneezing, and spittle. These droplets are bigger than the pore sizes of most masks and only remain airborne for a few seconds after they are emitted.
  • For more than a year, the World Health Organization and the U.S. Centers for Disease Control and Prevention denied and downplayed the threat of aerosol transmission while issuing guidelines that don’t amply prevent it. This enabled C-19 to decimate the most vulnerable members of society, like those in hospitals and nursing homes.
  • The CDC and WHO quietly admitted in the spring of 2021 that aerosols pose a major threat of transmission but have still not adequately updated their guidelines to reflect this reality. This has allowed countless preventable deaths to continue.
  • The risk of aerosol transmission can be greatly reduced by disinfecting air with ultraviolent (UV) light, which is part of the energy spectrum emitted by the sun. This simple and safe technology neutralizes airborne microbes and has been successfully used to control the spread of contagious respiratory diseases for more than 80 years.
  • Randomized controlled trials—which are the “gold standard” for clinical research—have repeatedly measured the effects of masks on preventing the spread of contagious respiratory diseases. These trials have found inconsistent benefits from N95 masks in healthcare settings and no statistically significant benefits from any type of mask in community settings.
  • The only randomized controlled trial that evaluated cloth masks found that mandating them causes significant disease transmission in high-risk healthcare settings.
  • Observational studies—which are a weaker form of evidence than randomized controlled trials—find that masking schoolchildren provides negligible or no benefits.
  • Lab studies—which are the weakest form of clinical evidence—don’t support the notion that surgical or cloth masks reduce the transmission of Covid-19.
  • Masks of all types have negative impacts on some people, including headaches, difficulty breathing, increased cardio-pulmonary stress during exercise, marked discomfort, and weakened social bonds.
  • Because humans create carbon dioxide as they breathe, the CO2 concentration of the air they exhale is about 100 times higher than in fresh air. Masks restrict airflow and thus cause the wearers to rebreathe some of the air they exhale.
  • The average CO2 concentrations inhaled by people wearing N95 masks range from 2.6 to 7.0 times OSHA’s work shift limit for CO2. These levels cause headaches and chest pains in some people.
  • The average CO2 concentrations inhaled by people wearing cloth and surgical masks range from 2 to 3 times the government CO2 limits for classrooms in many countries. These levels may impair certain high-level brain functions like initiative, strategic thinking, and complex decision-making.

The leaders of big tech corporations like Facebook, Twitter, and Google/YouTube have empowered government officials who misled the public about every matter above and others. Together, they continue to do so by engaging in actions that resemble common disinformation tactics. These include but are not limited to cherry-picking, censorship, muddying the waterscitation bluffsnon-sequiturs, half-truths, and outright falsehoods.

Opinions Are Not Science

very common and naive talking point about masks is that “experts say” they reduce the spread of Covid-19. Such statements are oblivious to the reality that other experts disagree with that opinion, like these for example:

  • Dr. Erica Shenoy, the Associate Chief of the Infection Control Unit at Massachusetts General Hospital, along with four other medical professionals, wrote in the New England Journal of Medicine that “wearing a mask outside health care facilities offers little, if any, protection from infection.”
  • Dr. Martin Kulldorff, a Professor of Medicine at Harvard Medical School, has stated, “Children should not wear face masks” because “they don’t need it for their own protection and they don’t need it for protecting other people either.”
  • Tamara van Ark, a public minister in The Netherlands, announced the conclusion of the nation’s National Institute for Health as follows: “Because from a medical perspective there is no proven effectiveness of masks, the Cabinet has decided that there will be no national obligation for wearing non-medical masks.”
  • Dr. Joseph Allen, an associate professor and the director of the Healthy Buildings program at Harvard University, wrote, “The truth is, for kids, Covid-19 is like the flu, and we don’t make kids wear masks in school for that.”
  • Dr. Shamez Ladhani, a professor of pediatric infectious diseases and vaccinology at St. George’s University of London, wrote that masking may help reduce Covid-19 transmission when used with other “infection control measures, but I have yet to see any convincing evidence that masking in and of itself significantly contributes to reducing infection and transmission” in schools and other institutional settings.
  • Dr. Jay Bhattacharya, a Professor of Medicine at Stanford University, said, “On net, I think the masks not only have not been effective, but have been harmful.”
  • Dr. Lisa Brosseau and Dr. Margaret Sietsema, researchers specializing in infectious diseases and respiratory protection, wrote, “There is no scientific evidence” that “cloth or surgical masks” are “are effective in reducing the risk of SARS-CoV-2 transmission.”

Regardless of what any experts say or how many say it, their opinions do not constitute scientific facts. Yet, journalistscommentators, and “fact checkers“ often treat the mere opinions of selected experts as “facts” or “science,” and politicians use the phrase “science says“ as if it magically turns claims into facts.

Such misuse of the word “science” has been a longstanding problem. As the renowned physicist Richard Feynman remarked half a century ago, “When someone says, ‘Science teaches such and such,’ he is using the word incorrectly.” People who are actually discussing science, explained Feynman, don’t “say science has shown”—but rather “this experiment, this effect, has shown.”

This article presents actual science, and there is no substitute for it when lives are on the line. Although greatly condensed from more than 500 hours of research, these thoroughly vetted facts will take more than an hour for most people to read. This is the price of being informed instead of indoctrinated.

Easy vs. Hard Measurements

Because masks have been used in operating rooms for more than a century, many studies have been conducted on them dating back to at least 1935. One might assume that these studies quickly found benefits given that the main purpose of surgical masks is simple: to prevent bacteria from the mouths and noses of surgeons from falling into the open wounds of their patients.

Yet more than half a century later, a 2001 paper in the Journal of Hospital Infection reviewed all known studies about “surgical face masks in the operating theatre” and found that their “effectiveness remains unresolved.” A 2016 paper found the same. Such outcomes commonly occur when the effects of something are very minimal or difficult to measure.

Measuring the impact of masks on the spread of infectious diseases in homes and public places is considerably harder than in operating rooms. This is because such settings are far more diverse and less controlled than operating rooms, which are subject to strict infection control protocols.

These facts suggest that cocksure and simple-minded statements like “masks work” should be treated with skepticism.

Strong vs. Weak Studies

In 2019—the year before C-19 pandemic began—the World Health Organization published a lengthy analysis of different strategies to limit the impact of the flu in “community” or “non-healthcare“ settings. The analysis found “there was no evidence that face masks are effective in reducing transmission” of the flu in these situations.

Covid-19 differs from the flu, and one of the main differences is that C-19 is much more transmissible. This raises the question: How can masking reduce the community spread of C-19 when there is “no evidence” that it does so for the flu?

Fortunately, a vital tool to answer that question is provided in WHO’s supplement to the same analysis. In it, WHO correctly notes that the key to sorting out masses of studies is to rank the “quality of evidence” from strongest-to-weakest in the following order:

  1. Randomized controlled trials (RCTs): These are studies in which people are randomly assigned to receive or not receive a certain treatment. Done properly, these are the “gold standard“ for clinical research because they provide “a rigorous tool to examine cause–effect,” which “is not possible with any other study design.” That is why the medical textbook Rutherford’s Vascular Surgery calls RCTs “the pinnacle in clinical design.”
  2. Observational studies: These studies observe the outcomes of people who have not been randomly assigned a certain treatment. Unless their results are mathematically and logically overwhelming, observational studies can “rarely” determine the effects of a treatment because a host of other factors are always at play when it comes to people’s health. For example, measuring the C-19 death rates of nations with and without mask mandates cannot determine the effects of the mandates because many factors impact C-19 death rates. As documented in a 2018 paper in the European Heart Journal, “it is not possible to make reliable therapeutic inferences from” observational studies.
  3. Laboratory and simulation studies. These are experiments conducted under artificial conditions and are typically the weakest form of clinical evidence. As explained by the UK’s Department of Health, such “studies provide only theoretical evidence” because they “are run in controlled environments that may not accurately reflect the behaviours that we observe in real life.” Likewise, a 2020 paper in a German medical journal explains that such studies can “provide important mechanistic insights” about Covid-19 transmission, but they “never approximate real-world conditions,” and thus, they should “not directly inform policy decisions.”

The quality gaps between those types of studies are so great that WHO adopted a “general principle” to “not review simulation studies” if observational studies were available and to “not review observational studies or simulation studies” if RCTs were available.

However, WHO broke that rule for masks while explaining that even though all “ten RCTs” showed “no evidence that face masks are effective in reducing transmission” of the flu, “there is mechanistic plausibility for the potential effectiveness of this measure.” Thus, WHO flouted its own principle and “conditionally recommended” that asymptomatic people wear face masks “in severe epidemics or pandemics, to reduce transmission in the community.”


Beyond the general quality of a study, another important factor to consider is how applicable it is to the issue at hand. Studies on trained nurses who wear N95 masks to reduce the spread of tuberculosis during 10-minute interactions in sanitized hospital wards are less relevant to the present issue than studies on 5-year-olds wearing cloth masks for six hours in poorly ventilated schoolrooms during the C-19 pandemic.

Of great import for understanding the coming facts, the three main types of masks from the highest-to-lowest quality are:

  1. N95 masks or respirators, which are mainly intended to prevent wearers from inhaling fine aerosols and microscopic particles. These are supposed to be used only oncemust meet strict filtration standards, and must be moldable to each user’s face to form a tight seal. Because N95s heavily restrict breathing and “may place a burden on an employee’s health,” OSHA requires employers to conduct a medical evaluation of each employee who wears them.

  1. surgical or medical masks, which are primarily designed to prevent wearers from spraying liquid droplets and large particles on other people. The FDA’s Covid-19 guidance for these masks states that they cannot be labeled “for antimicrobial or antiviral protection” and cannot make “filtration claims” for particles of any size. Per a 2013 paper in the Journal of Occupational and Environmental Hygiene, surgical masks have “poor filtration” and a “poor fit,” and thus, they “cannot be expected to significantly reduce the inhalation of infectious aerosols.” They are supposed to be used only once.

  1. cloth masks, which are made of common fabrics that tend to be highly permeable. These masks were already worn before the C-19 pandemic in developing countries because they are inexpensive and can be used more than once. The CDC says they should be washed at least once a day, and washing them makes the fabrics even more permeable.

In July 2020, the Journal of the American Medical Association published a commentary titled “Universal Masking to Prevent SARS-CoV-2 Transmission—The Time Is Now.” The authors—all of whom were CDC employees—argued that the benefits of using masks during surgery are relevant to the general public. This leap of logic conflates surgical masks with cloth masks, sterilized operating rooms with subways, and open wounds with people’s faces.


The authors also claimed—without citing any research—that it would be “absurd” to conduct surgery without masks “because it is known that use of face coverings under these circumstances reduces the risk of surgical site infection caused by microbes generated during the surgical team’s conversations or breathing.”


That assertion is at direct odds with the strongest, most relevant research on this issue. This was summarized in a 2016 paper published by “the leading journal and database for systematic reviews in health care.” After conducting an extensive search for all available RCTs on the use of surgical masks to prevent wound infections, the authors located three trials and found “there was no statistically significant difference in infection rates between the masked and unmasked group in any of the trials.”


This straightforward example dramatically illustrates how the claims of “experts” published in one of the world’s leading medical journals can be at odds with documented facts. Yet with callous disregard for the facts—and thus the wellbeing of people—Google/YouTubeFacebook, and Twitter have banned factual statements about masks that conflict with the opinion of their chosen experts.


Gold Standard Studies

Like the 2019 analysis of RCTs by the World Health Organization, other comprehensive analyses of gold standard studies have found no evidence that low-quality masks reduce the spread of the flu in community settings. Moreover, such studies have found limited evidence that any type of mask protects against the flu in any setting:

All of those flu RCTs are highly relevant to Covid-19 because:

Broadening the research beyond the flu to other types of infectious respiratory diseases, RCTs have found inconsistent evidence that higher-quality masks may help in healthcare settings but no statistically significant evidence that any type of mask helps in community settings:

The last of those studies is particularly relevant to C-19 mask mandates because:

When the RCT on cloth masks was published in 2015, the lead author of the study, Raina MacIntyre of the University of New South Wales (Australia)—stressed “it is important for global disease control that the use of cloth masks be discouraged in high-risk situations.” However, she and some of her coauthors began backpedaling five years later in 2020 when governments began mandating masks for C-19. MacIntyre and company did this by:

The last of those papers—which was coauthored by MacIntyre and published by the CDC—buries the results of the RCT two-thirds of the way into a lengthy paragraph. There, the authors reveal that the “intent-to-treat analysis”—which is the actual RCT—“showed no significant difference” in outcomes between the people who were assigned to wear masks and not wear masks.


While concealing the gold standard results of their own study, MacIntyre’s team focused their analysis on a subset of people who had the highest “adherence to mask use.” This violates the very essence of RCTs, which are supposed to be “randomized control trials.” Randomization is the linchpin that allows these studies to determine cause and effect.


For that reason and others, Dr. Alyson Haslam of the Oklahoma State University Center for Health Sciences Research publicly criticized MacIntyre and her colleague (Dr. Abrar Ahmad Chughtai) for spreading “incorrect/biased summaries of published articles.”


MacIntyre and Chughtai replied without confronting the central fact of this matter: people who were more diligent about wearing masks may have taken other precautions to avoid getting sick, like social distancing or washing their hands more often. In other words, their conclusion that masks “appeared to be effective” is not based on RCTs, even though their paper claims to be an analysis of “randomised controlled trials.”


Furthering that misleading impression, MacIntyre and Chughtai end their reply to Haslam by declaring that “a WHO-commissioned study has shown that masks reduce the risk of infection with beta-coronaviruses by 85%, and are equally protective in community and healthcare settings.” However, that WHO-commissioned study is not an RCT but an analysis of observational studies. Thus, it cannot prove that “masks reduce the risk” of anything. That is precisely why the authors of the study write that their results have “low certainty.”


Compounding the deceit, the CDC published a study in July 2020 that cites MacIntyre and Chughtai’s paper while claiming that they analyzed “randomized trials and concluded that use of face masks and respirators appeared to be protective in both health care and community settings.” Again, none of those findings are actually based on RCTs.


Beyond the CDC’s false portrayal of non-RCTs as RCTs, the same CDC study ignores the actual RCTs, all of which show no statically significant benefit from community masking. To reiterate, these studies are systematically analyzed in papers and reports published by:

The misinformation spread by MacIntyre, Chughtai, and the CDC cannot fool informed people with time to vet it, but it can muddle the issue enough to prevent all but the most tenacious researchers from finding the facts. Combined with the power of big tech corporations who suppress facts that contradict the CDC’s claims about masks, this is more than enough misinformation and censorship to keep the vast bulk of people in the dark.


In summary, a large array of gold-standard studies have found inconsistent benefits from higher-quality masks in healthcare settings and no statistically significant benefits from any type of mask in community settings. Crucially, the only RCT to evaluate cloth masks found that mandating them causes significant disease transmission in high-risk healthcare settings.


Disregarding RCTs

Faced with a mountain of RCTs that undercut their claims, proponents of community masking ignore or deceitfully dismiss them. For example, the CDC’s “Science Brief” on “Community Use of Cloth Masks” does not rely on a single RCT to support its claim that “universal masking” reduces the spread of C-19.

Instead, the CDC ignores all but two of the RCTs, which it brushes aside in a single paragraph. One of these is the lone RCT on cloth masks, and the manner in which the CDC tries to spin it is a textbook case of junk science:

Bottom line: the manner in which certain people disregard and twist gold-standard studies on masks says little about the studies but reveals a great deal about the people.


Observational Studies

To repeat, observational studies cannot determine the effects of medical treatments except in rare cases. This is because many factors influence people’s health, and without an RCT, it is impossible to isolate the effects of any one factor from all of the others. A simple but vivid example that highlights this reality is the number of C-19 deaths in Texas before, during, and after its mask mandate:



This observational data shows that the rate of C-19 deaths was consistently higher during the mask mandate, but deaths began rising again more than three months after the mandate ended. In isolation, these trends look like the mask mandate did nothing to stem the tide of C-19 deaths and may have even intensified them, but the reality is that countless other factors are involved, like:

Without accounting for those and many other variables, there is no way to objectively measure the effects of masks on C-19 deaths. RCTs naturally do this, but an observational study cannot.


Researchers often use statistical techniques to “control” for such variables in observational studies, but these methods cannot rule out the possibility that other factors are at play. Also, the techniques used to perform such analyses are prone to pitfalls.


All of these realities boil down to one of the most important and neglected facts of science: association does not prove causation. This is commonly taught in high school math, but it is routinely ignored by commentatorsjournalists, and Ph.D.’s.


Because observational studies can only determine associations, they cannot be used to draw firm conclusions about causation unless the results are mathematically and logically overwhelming.


After investing more than 500 hours of research on masks, Just Facts found only one observational study that addresses their necessity and rises to that level of certainty. Published by the New England Journal of Medicine in February 2021, the study was conducted in Sweden from March to June of 2020 when the nation experienced substantial growth in C-19 deaths:




Unlike smaller studies with convenience samples that may not reflect the broader population, this study included all of Sweden’s 1.95 million children aged 1 to 16 years who attended school in the spring of 2020. During this period:

The study found that:

Strengthening those results, the Public Health Agency of Sweden published a study in July 2020 that found “no difference” in the incidence of C-19 infections among school-aged children in Finland and Sweden—even though Finland closed its schools, while Sweden left them open without mandating or encouraging masks.


Likewise, a March 2021 paper in the Proceedings of the National Academy of Sciences:

In combination, those massive observational studies provide fairly strong but not definitive evidence that closing schools or masking schoolchildren provide negligible or no benefits. In combination with the throng of RCTs on masks, this conclusion becomes nearly undeniable.

While ignoring this wealth of strong, comprehensive studies, the CDC’s Covid-19 guidance for K-12 schools declares:

The CDC claims that those policies are “based on current scientific evidence” while linking to a CDC “Science Brief” which cites observational studies that prove nothing of the sort. For example, the brief cites:

After proclaiming that those and other studies demonstrate the “success” of mask mandates, the CDC cites two observational studies that supposedly show “inconsistent mask use may have contributed to school-based outbreaks.” Absurdly, these consist of:

In other words, the CDC blames a handful of C-19 cases on less-than-perfect mask usage in a school district where masks were required, compliance was “high,” and interviews failed to detect even slight non-compliance in four of the nine clusters that caught C-19. Yet, the CDC ignores two million students in Sweden who rarely wore masks, rarely became infected, and not one of whom died from C-19.


After closing out the section on masks, the same CDC “Science Brief” craftily slips the following statement into a section on “Physical Distancing”:

K–5 schools in Norway had minimal child-to-child and child-to-adult transmission with masks only required for adults, one meter between all individuals, and two meters between student cohorts.


In reality, the study mentions masks only once and states: “Use of face masks is not recommended in schools in Norway.” This means that C-19 transmission was minimal in schools that practiced social distancing but did not require or even recommend masks. Put bluntly, the CDC buried and twisted this fact that undermines their central claim.


The CDC makes it very difficult for readers to notice how they distort these studies. They do this by using unclickable footnotes and failing to link to the vast majority of the sources they cite. Thus, readers must note the footnote numbers, scroll down to the bottom of the webpage to locate the source, conduct a separate search for the source, and then scroll back up to the location where they were reading. Compare that runaround to a typical academic journal, where all of this can be done with a few simple clicks.


The CDC’s “Science Brief” on cloth masks is similarly deceitful. It makes its sources inaccessible, distorts the lone RCT on cloth masks, and ignores observational studies that don’t fit the narrative. Perhaps worst of all, it cites more than a dozen observational studies without ever revealing their fatal flaw: an inability to determine the actual effects of masks.


In contrast, the government health agencies of other nations, like Public Health England, are forthright about that reality and bluntly state that observational studies on masks are “highly subject to confounders,” and thus, they constitute “weak evidence.”


The CDC’s record of double-talk, double-standards, and outright falsehoods about masks should give pause to anyone who would blindly trust their pronouncements. Yet, tech giants like Google/YouTube and Facebook promote the CDC’s claims as unquestionable and censor people who challenge them.


Laboratory/Simulation Studies

When assessing the effects of masks and other medical interventions, the weakest form of evidence is laboratory/simulation studies. The World Health Organization, other public health agencies, and medical journals emphasize that such studies should “not directly inform policy decisions” because they are highly uncertain. In the words of Public Health England, this is because they:

Despite providing flimsy clinical evidence, the facts surrounding these studies reveal strong evidence about how false beliefs about masks took root and the deadly consequences of those dogmas.


First, it is critical to understand how respiratory viruses spread because this is at the core of the issue. A 2021 paper in the journal Nature describes four primary ways in which such diseases can be transmitted:

  1. Direct physical contact when people touch one another.
  2. Indirect physical contact when people touch, sneeze, or cough on objects that are later touched by other people who then touch their mouth, nose, or eyes.
  3. Large respiratory droplets generated by talking, coughing, and sneezing that can travel through the air between people but are too heavy to stay airborne for more than a few seconds.
  4. Microscopic respiratory vapors (also called “airborne particles” or “aerosols”) generated by breathing, talking, coughing, and sneezing that are light enough to stay airborne for more than a few seconds.

If a disease is mainly spread by the second and third of those mechanisms, masks of all types can be helpful because they block large droplets created by coughing, sneezing, and “say it don’t spray it” talking.


But if a disease is mainly spread by the fourth and final mechanism, wide-ranging medical sources are clear that surgical and cloth masks are practically useless. This is because the pore sizes of these materials are not small enough—and the fit of such masks are not tight enough—to effectively block the spread of microscopic aerosols:

The facts above apply even more so to cloth masks, most of which have much worse filtration than surgical masks:

Returning to the issue of whether Covid-19 is transmitted by aerosols, big tech’s chosen medical authorities butchered the pivotal facts of the matter. For a prime example, the World Health Organization published a “fact check” in March 2020 insisting that “Covid-19 is NOT airborne” and “is mainly transmitted through droplets” that “are too heavy to hang in the air”:




Similar claims about “droplets” were widely propagated by the likes of the CDC, Holmes Lybrand of CNN, and Paul Krugman of the New York Times.

Exposing the hollowness, prevalence, and deadly potential of such claims, 14 authors of a June 2020 paper in the journal Environment International:

Six months later in November 2020, the journal Clinical Infectious Diseases published a statement signed by 239 scientists documenting “more than enough supporting evidence” that C-19 could be spreading via aerosols. These scientists also:

The failure of certain government agencies and media outlets to embrace those facts is not a case of “science evolving.” A wealth of studies have shown all along that aerosols play a dominant role in the transmission of all infectious respiratory microbes, including the one that causes C-19. In contrast, there is no such evidence for droplets or indirect contact:

After the publication of nearly all of those journal papers—plus others with similar findings like thisthisthisthisthis, and this, and this—the World Health Organization and CDC nonchalantly walked back their longstanding and lethally false assertions about droplets and aerosols:

Instead of candidly announcing that they were wrong about this life-or-death issue, WHO and the CDC made those changes without fanfare.

Moreover, the CDC made a blatant attempt to cover its tracks. On the same day that the CDC changed its webpage on “How COVID-19 Spreads,” it created a “Scientific Brief” titled “SARS-CoV-2 Transmission“ that claims, “Although how we understand transmission occurs has shifted, the ways to prevent infection with this virus have not.” In reality, the implications of this shift are staggering:



The harm caused by such policies is vividly illustrated by a recent New York Times article about nursing home residents who were “trapped indoors under lockdown” orders for nearly a year in Toronto, Canada (“the lockdown capital of North America”). Under government orders, the home forbid residents from leaving their buildings for “even a stroll” during “all but five weeks between March 2020 and June 2021.” Yet, the facility suffered a C-19 outbreak in which 35 staff and 53 residents tested positive, four of whom died.


Beyond the physical, cognitive, and emotional toll of isolating people and locking them indoors for a year, those strict nursing home lockdowns confined residents to indoor areas where aerosols are more likely to spread. Thus, 31% of Canadian nursing homes had C-19 infections among their residents or staff, and 31% of these led to outbreaks of 25 or more cases. As a result, about 80,000 residents were infected, and more than 14,000 of them died. Much of this could have been avoided if government mandates reflected the reality that C-19 is primarily transmitted by aerosols instead of droplets.


Given the abundance of evidence that is how C-19 spreads, and the lethal consequences of failing to recognize it, how could so many government agencies deny this reality for so long? They embraced a naive assumption that diseases commonly transmitted over short distances must be spread by droplets instead of aerosols—even though scientific journals explicitly debunked this fallacy:

Even though the CDC has slyly admitted the truth about aerosols, it continues to overlook the threat in ways that can cause harm. Illustrating the depths of the CDC’s real or feigned blindness, it published a study on August 27, 2021 that:

Unrealistic Lab/Simulation Studies

Despite the multitude of lab studies indicating that surgical and cloth masks are practically useless at reducing disease transmission by airborne viruses, the CDC insists that such studies show just the opposite. They do this by ignoring the more lifelike studies detailed above while cherry picking and misrepresenting unrealistic studies that:

For example, the anonymous authors of the CDC’s “Science Brief” on cloth masks cite two studies to support their claim that “multi-layer cloth masks” can “block up to 50–70%” of “fine droplets and particles (also often referred to as aerosols) smaller than 10 microns.” Neither of these studies come anywhere close to reflecting real-world circumstances.


The first of them, published in 2020 by the journal Aerosol Science and Technology, was a lab “simulation” of “a single cough” in “two consecutive tests.” It found that a 3-ply cotton cloth mask blocked 51% of aerosol particles smaller than 7 microns and 28% of particles smaller than 0.6 microns. Unlike the “50–70%” blockage rate claimed by the CDC, the 28% figure is more relevant to C-19 since greater than 90% of all virus-carrying aerosols exhaled by primates infected with C-19 are less than 1 micron.


Most importantly, the study mimics wearing a brand new face mask for a few seconds and fails to account for the following realities that other studies have addressed:



The other study cited by the CDC was published by the journal mSphere in 2020. This study is more realistic than the first because it was conducted over 20 minutes instead of a few seconds, but this is still well short of the length of a school day or hospital shift. Nor does the study account for:

Another major flaw of the study is that the average size of the aerosol particles generated for the experiment was 5 microns. Again, more than 90% of particles exhaled by primates infected with Covid-19 are less than 1 micron. The study’s authors note that “some” of the larger “droplets likely gradually evaporated and changed to aerosols,” but this does not change the fact that the starting sizes of the particles in the experiment are much larger than the starting sizes of real-world C-19 particles.


The CDC’s “Science Brief” also cites four studies to weave a tale that cloth masks “limit the forward spread” of aerosols “that are not captured.” Yet, one of those same studies destroyed the CDC’s narrative when it found that surgical and cloth masks “generate significant backward leakage jets that have the potential to disperse virus-laden fluid particles by several meters.” Thus, the study concludes that:

the effectiveness of the masks should mostly be considered based on the generation of secondary jets rather than on the ability to mitigate the front throughflow.



And yet again, the CDC makes it hard for readers to discover these vital facts by using unclickable footnotes and not linking to the study.

Also, the CDC’s 4,000+ word “Science Brief” on cloth masks does not contain the word “leak” or any synonym for it. The deceitfulness of that omission is underscored by a 2010 paper in the Annals of Occupational Hygiene which emphasizes that “face seal leakage of aerosol particles” is “a critical component of respiratory protection.”


In sum, a torrent of facts related to lab studies prove that the CDC, WHO, and other agencies that were formed to protect people’s health:

Throughout all of this, massive corporations like Google/YouTube and Facebook helped spread these deadly fictions.


Asymptomatic/Presymptomatic Transmission

Another misleading aspect of the CDC’s case for masks is the claim that people with asymptomatic and presymptomatic C-19 can easily transmit the disease.

The first paragraph of the CDC’s “Science Brief” on cloth masks declares that masks are “especially relevant for asymptomatic or presymptomatic infected wearers who feel well and may be unaware of their infectiousness to others, and who are estimated to account for more than 50% of transmissions.” The facts, however, show that claim has no basis in reality:

So how can the CDC claim just the opposite? By citing two studies that use speculative models, while ignoring every study that uses real-world data. Both of the studies cited by the CDC state that they are based on a “model,” and the second one is explicit that the model uses the “assumption” that asymptomatic people “are 75% as infectious as those who do develop symptoms.”


In other words, the CDC cherry picks studies that rely on an assumption that the CDC misrepresents as a fact. And once again, the CDC makes it hard for readers to discover this by using unclickable footnotes and not linking to the studies.


The Harms of Masks

Facebook has enacted a policy to censor “false health information” that is “widely debunked by leading health organizations such as the World Health Organization and the Centers for Disease Control and Prevention.” This includes any “claims that wearing a face mask can make the wearer sick.”


That policy is self-contradicting because the World Health Organization published “interim guidance“ on masks in 2020 that reveals exactly what Facebook bans everyone from saying. Per the guidance, “The likely disadvantages of the use of masks by healthy people in the general public include”:

Reams of facts from science journals confirm those and other harms of surgical and cloth masks.



A range of studies show that surgical and N95 masks induce headaches in some people.


In 2009, the American Journal of Infection Control published the results of a small RCT of surgical masks involving 32 healthcare workers for 77 consecutive days. It found that workers assigned to wear masks “were significantly more likely to experience headache” than the maskless group. On average, the daily headache rate for maskless workers was 1.3%, while it was 4.9% for mask wearers—a 3.8-fold increase.


Similarly, a study published in 2019 by the journal BMC Infectious Diseases found that 6% of hospital workers who wore a surgical mask for one shift reported a headache.


Because N95 masks have finer filters and tighter fits than surgical masks, they restrict breathing more heavily, cause greater facial pressure, and are more uncomfortable. As such, a study published in 2006 by the journal Acta Neurologica Scandinavica found that 37.3% of 212 frontline healthcare workers in a Chinese hospital “reported headaches when they wore the N95 face-mask.” Among the workers who experienced headaches, 62.7% “had no pre-existing headaches.”


Similarly, a study published in 2020 by the journal Headache evaluated 158 frontline healthcare workers in a Singapore hospital early during the C-19 pandemic and found that:


Though far from universal, a substantial portion of people who wear masks report difficulty breathing:

The studies above lay out several reasons why masks may cause headaches and problems with breathing, such as increased carbon dioxide, excessive heat, and facial pressure. These and other factors are explored next.


Carbon Dioxide

Because humans create carbon dioxide as they breathe, the CO2 concentration of the air they exhale (4% to 5%) is about 100 times higher than in fresh air (0.04%). Although CO2 is generally non-toxic, ingesting too much of any substance will cause harm. Thus, governments throughout the world set maximum indoor CO2 limits for homesschoolssubmarines, and other places where CO2 can accumulate because fresh air does not flow freely.


Similarly, science journals have proven that face masks restrict airflow and cause the wearers to rebreathe some of the air they exhale. This raises the CO2 levels in the air they inhale to well above that of fresh air. These levels are far beyond government CO2 limits for schools and workplaces, and certain people have tried to bury these facts:

All of the studies above were conducted in well-ventilated labs with CO2 levels close to that of fresh air (400 ppm). In the real world, indoor CO2 levels are often much higher, and this may push the CO2 concentrations in the masks to well beyond what lab studies have found. For example, a 2017 paper in the journal Indoor Air summarizes the results of more than 25 CO2 studies in schools across the world as follows:

On the other hand, government exposure limits for CO2 and other substances typically include a margin of safety to address uncertainties and protect people with serious health problems. Thus, the CO2 levels measured in masks don’t necessarily cause harm just because they exceed government limits for workplaces and schools. That said, ample studies show that the CO2 levels in masks do cause harm, especially in N95s.


The 13,000 to 35,000 ppm CO2 concentrations in N95 masks and KN95 masks are in the range of the 28,000 ppm level found to cause chest pain and the 20,000 ppm level found to cause headaches in a range of studies summarized by a 2007 paper in the Proceedings Of The National Academy Of Sciences.


Far below those levels, the 2,000 to 2,900 ppm CO2 concentrations in surgical and cloth masks may impair certain high-level brain functions:

In contrast, a study published by the journal Indoor Air in 2017 found “no statistically significant effects” on the “cognitive performance” of 25 people exposed to 3,000 ppm of CO2 for 255 minutes. However, locked behind a $59 paywall, the paper reveals that there were significant effects on some measures of cognitive performance, even though none of the tests were very demanding:

While ignoring those genuine facts from science journals, Facebook’s “independent fact checkers” like PolitiFact have quoted the mere opinions of cherry-picked “experts” to claim that “using ordinary cloth or surgical masks poses little or no risk from CO2.” Facebook then uses such bogus “fact checks” to suppress actual facts and malign those who share them.


One of the most sophomoric arguments made by Facebook’s enforcers comes from a group called Health Feedback and is parroted by another such group called Lead Stories. They claim that “face mask filters are small enough to keep out infectious droplets containing viruses, but gas molecules such as carbon dioxide and oxygen can still pass through freely.” This is grossly misleading in two respects.


First, the issue is not if CO2 penetrates masks (it obviously does)—but if a significant amount of CO2 is reinhaled because it stays inside the masks between breaths. The facts are overwhelming that this is what happens:

Second, Facebook’s luminaries seem to be ignorant of the fact that C-19 spreads mainly through aerosols, not droplets. They don’t even seem to understand the difference between them, as evidenced by the following sentence where they treat the words as synonyms: “The purpose of these masks is to reduce contact with infectious droplets (aerosols), which can be generated by someone who coughs or sneezes, and thereby minimize the risk of infection transmission.”

Just Facts has communicated with Facebook about the simple-minded falsehoods spread by its so-called “independent third-party” fact checkers, and Facebook has repeatedly dodged these questions:

  1. Given that Facebook has hand-selected these organizations to be the judges of truth on your platform, do you hold them to actionable standards and count quality violations against them?
  2. If so, what exactly are these standards and the repercussions for violating them?
  3. If not, why are you vesting certain people with unchecked authority to use Facebook to censor others, sow misinformation, and slander the reputations of scholars.

Cardio-Pulmonary Stress

An array of science journals have published studies showing that exercising with a mask causes heart and lung stress, negatively impacts performance, and may have caused some deaths:

Continuing its pattern of deceit, the CDC’s “Science Brief” on cloth masks ignores all of the studies above and cherry picks studies that use low exercise intensities, low exposure times, imprecise measurements, or gravely misleading summaries, like these:

In short, the CDC’s risk-free portrayal of exercising while masked is false and dangerous.

Furthermore, people who have acted in accord with the facts of this matter have paid a heavy price. A prime example is Bradley Keyes, a high school track and field coach who was fired by Pembroke Academy in New Hampshire for refusing to make his athletes wear masks.


Heat & Discomfort

The heat, humidity, and other discomforts of wearing a mask are not merely annoyances. This is because “heat and moisture trapping beneath surgical face masks,” as explained in the Journal of Hospital Infection, may cause “decreased mental and physical performance.”


Measured by the heat index, the interiors of masks can be sweltering, even in climate-controlled rooms. A study published in 2012 by the journal Respiratory Physiology & Neurobiology found that when “young, healthy adults” engaged in “low-moderate” intensity exercise with a surgical mask, the air inside the masks averaged 91°F (32.74°C) and 91% relative humidity. This equates to an heat index of 127°F (52.9°C). For comparison, the air in the room where the test was conducted was 71°F (21.47°C) and 23% relative humidity, a heat index of 69°F.


A study published in 2020 by the journal Clinical Research in Cardiology measured effects of surgical and N95 masks on 12 healthy males aged 32–42 as they exercised. It found that the masks “significantly impair the quality of life of their wearer” by causing “breathing resistance, heat, tightness,” and “severe subjective discomfort during exercise.”


A study conducted in 14 Vietnamese hospitals and published in 2015 by the journal BMJ Open found that 40.4% of healthcare workers who wore a cloth or surgical mask reported “adverse events associated with facemask use,” with “general discomfort” and “breathing problems” being “the most frequently reported adverse events.”


In 2021, the Journal of Transport & Health published a covert study of 182 passengers on subways and local trains in the area of Paris, France. It found that during a median observation time of 8 minutes, 48% of people touched their masks, and they did so at an average rate of 15 times per hour. The study also revealed an “increased tendency to touch the face while wearing a face mask” and noted that this “might increase the risk of transmission and self-contamination.”


The implications of mask touching are much broader than transmission and contamination. This is because momentary distractions (like adjusting a mask) can hamper job performance. A series of experiments published by the Journal of Experimental Psychology in 2008 found that “an entirely irrelevant distractor can interfere with task performance” by causing “increased error rates” and “response times.”


For people working in hospitals, factories, and offices where mental sharpness or attention to detail are vital to safety or performance, the discomforts and distractions of masks could make the difference between life and death. This is not a mere hypothetical because the fatal line can be easily crossed in certain environments. Based on a systematic literature review published by the Journal of Patient Safety in 2013, “there are at least 210,000 lethal” errors in U.S. hospitals each year, and “the true number” is “estimated at more than 400,000 per year.”

Social Bonds & Communication

Along with headaches, trouble breathing, cardio-pulmonary stress, discomfort, and cognitive impairment, another significant realm of harms caused by masks is relational:

Human beings, and especially youth, are highly social creatures. Masks stifle that by interfering with bonding and communication, which are essential to people’s mental healthphysical health, and productivity.


Because association does not prove causation, it is impossible to empirically determine if widespread masking has played a role in the accompanying surges of depression and anxiety among youth, suicides among teens and young adults, and drug overdoses among people of all ages. But given the effects of masks on relationships, it would be mindless and irresponsible to ignore or dismiss this possibility.


Ultraviolent Air Disinfection

Beyond ordinary measures like social distancing, the risk of spreading diseases that are transmitted by aerosols can be greatly reduced by disinfecting air with ultraviolent (UV) light, an invisible part of the energy spectrum emitted by the sun. This simple and safe technology proficiently kills airborne microbes and has been successfully used to control the spread of contagious respiratory diseases for more than 80 years.


In 1942, the American Journal of Epidemiology published a series of experiments conducted at two Philadelphia-area schools with students from grades 1 to 12 during 1937–1941. The researchers installed UV lights to disinfect the air above students’ heads in some hallways, common rooms, and classrooms. This is called “upper room” UV.


The authors referred to these areas as “irradiated” even though “only indirect irradiation” was used in the classrooms. This was a vital aspect of the study design because it prevented the UV light from neutralizing microbes near the faces of the students or anywhere below them. Hence, the UV light could not prevent disease transmission via respiratory droplets or contact between the students or objects they touched. In other words, the experiments would only be successful if the diseases were mainly spread by aerosols.


The experiments were seemingly successful and found “no epidemic spread” of measles, chicken pox, or mumps “among the highly susceptible groups of children of the primary schools within irradiated atmospheres, although epidemic spread has occurred among less susceptible groups of older children in the departments of the schools whose atmospheres were not irradiated.” Put simply, students rarely transmitted these diseases to each other in areas with UV lights, while they often did so elsewhere.

The results included a period during “the largest epidemic of measles from which the city of Philadelphia has ever suffered.”

The study was not an RCT, so other factor(s) besides the UV lights could have been at play. However, the authors noted that “the patterns of the epidemics” in these “schools were strikingly different from any previous experience.”

Another limitation is that there were opportunities for students to mingle in areas that were not irradiated (like an auditorium) and outside of school. Hence, the studies found no change in the “total numbers of colds after installation of the lights,” which could be due to “home and random infections.” This kind of transmission is more likely with colds than measles, chicken pox, or mumps because “adults as well as children” often have colds, “lasting immunity is not conferred” by catching a cold, and children are prone to have multiple colds during a winter season.

In 1961, the American Review of Respiratory Disease published a similar study without that limitation. Shortly before the “Asian influenza epidemic” of 1958, researchers equipped an entire wing of a Veterans Administration Hospital in Livermore, California with UV lights to disinfect the air above people’s heads. This time, the results were even more stunning:

This was not an RCT because the patients were not randomly assigned to the irradiated wing of the hospital, but it approximated one because:

Like the experiments in schools, the authors of the hospital study emphasized that the indirect UV light would only control the spread of “air-borne” or “aerosolized” particles. This adds to the mountain of evidence that contagious respiratory diseases are mainly spread by aerosols, not droplets or touching common objects.


In 2015, the American Journal of Respiratory and Critical Care Medicine published the results of a controlled trial of upper room UV disinfection on guinea pigs. For this experiment, air was pumped in from a hospital tuberculosis ward to rooms containing 180 guinea pigs. The study found that UV light reduced the odds of infection by 80%.


Some studies have failed to find benefits from upper room UV, but as explained in a 2010 paper in the journal Public Health Reports, the studies were conducted in situations where there was “a high risk of acquiring the same infection outside the location where” the UV was deployed, such as school buses. This is not an issue for places like hospitals and nursing homes, where UV lights can be installed wherever the patients and residents may be.


In addition to upper room systems, UV light can also be used to disinfect air while it passes through heating, ventilation, and air conditioning (HVAC) systems. This is called “in-duct” or “airstream” disinfection.


As well as can be determined without observational studies and RCTs, it appears that in-duct UV reduces the transmission of diseases that are spread by infectious aerosols. This is because lab and field studies have repeatedly found that these systems kill the vast bulk of airborne microbes that flow through them.


Some of the pros and cons of upper room versus in-duct UV systems are as follows:

Another option for disinfecting air with UV light is portable in-duct units. These commercial and consumer products are relatively inexpensive, and they can be strategically placed between people in close quarters like roommates and dinner guests. However, studies to measure their effectiveness are lacking. With regard to these matters:

The CDC is aware of UV disinfection technology but relegates it to a “supplemental treatment” when “options for increasing room ventilation and filtration are limited.” Meanwhile, a note at the top of the same webpage and others on cdc.gov instructs people to “wear a mask indoors in public if you are in an area of substantial or high transmission.” This is yet another example of how the CDC’s myopic agenda on masks is neglecting real opportunities to save lives.


Building Immunity

Another area of tunnel vision for the CDC and other government agencies is their focus on limiting Covid-19 cases, as opposed to deaths. The ramifications of this are quantified in a study published by the British Medical Journal in 2020, which found these stunning and “counterintuitive results”:

Those outcomes assume a C-19 infection mortality rate of 1% (higher than reality) and that widespread vaccination does not occur for 800 days (slower than reality), but the basic point remains the same: Lockdowns to control the spread of C-19 can actually cause more C-19 deaths by preventing the development of herd immunity among healthy people—the vast majority of whom are very resilient to the virus.


Those avoidable C-19 deaths are in addition to hordes of other deaths caused in the short run and long term by lockdown-induced depression, anxiety, missed medical care, unemployment, and poverty.


Scholarly Reviews

Just Facts asked several scholars who specialize in the disciplines addressed in this research to critically review it. Among those who did so, they assessed it as follows:

“This research is truly impressive, accurate, and important. Every doctor, nurse, parent, policymaker, and public servant should carefully read and act in accord with it. Overconfidence in the effectiveness of masks is dangerous, and it causes people to not recognize when masks are appropriate and how to properly use them. Further, mask mandates that are at odds with scientific facts are leading to widespread distrust that has long-term ramifications for public health.”

– Dr. Rodney Sturdivant, Ph.D. in Biostatistics, Director of the Statistical Consulting Center at Baylor University

“The sections of this research on social bonds and communication, which are among my primary areas of clinical expertise, are spot on and illuminate what I diagnose on an alarmingly regular basis. I look forward to the publication of this article, so I can share it with all of my patients.”

– Dr. Joseph P. Damore, Jr., M.D., Diplomate, American Board of Psychiatry and Neurology in General Psychiatry and Child and Adolescent Psychiatry



With remarkable consistency, the comprehensive facts detailed above prove that:

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