Aerosols, Anthony Fauci, City Journal, Cloth Masks, Cochrane Library, Dr. Robert Lending, Filtration Efficiency, Influenza, Jeffrey H. Anderson, Joe Biden, KN95, Mask Efficacy, Mask Fit, Mask Leaks, Mask Mandates, N95, Omicron Variant, OSHA, P95, Physics of Fluids, R95, Randomized Control Trial, RCT, Surgical Masks, Teachers Unions, Viral Transmission
Right at the start of the pandemic, Dr. Anthony Fauci insisted that masks were unnecessary, which was in line with the preponderance of earlier evidence. Later, he sowed confusion — and distrust — by claiming he said that to discourage a run on masks, thus preserving supplies for the medical community. That mix-up put a stain on his credibility among those who were paying attention, and the reversal was simply bad policy given what is well established by the evidence on mask efficacy.
No Mas, No Mask!
Despite my own doubts about the efficacy of masks, I went along with masking for a while. It gave me a chuckle to see people wearing them outside, especially runners, or on solo drivers. We knew by then that contracting Covid outside was highly unlikely. I was also amused by the idiotic protocols in place at many restaurants, where it was just fine to remove them once you walked a few feet to sit at your table, as if aerosols indoors were bound within narrow bands of altitude. Finally, I had reservations about the health consequences of frequent masking, which have certainly been borne out. Restricting air flow is generally not good for human health! Neither is trapping bits of sputum and hot, exhaled moisture rich in microbes right up against one’s muzzle. Still, I thought it polite to wear a mask in places of business, and I did so for a number of months.
In time it became apparent that the cloth and paper masks we were all wearing were a waste of effort. Covid is spread via fine aerosols and generally not droplets. That’s important because the masks in common use cannot block a sufficient level of Covid particles from escaping nor from penetrating through gaps and through the fiber itself. Neither can N95s if not fitted properly, as so many are not. And none of these masks can protect your eyeballs! When tens of thousands of tiny beads of aerosol are released with each cough or exhalation, a mask that stops 70% of them will not accomplish much.
The evidence began to accumulate that mask mandates were completely ineffective at “stopping the spread” of Covid. I then became an ardent anti-masker. I generally don’t wear them anywhere except medical buildings, and then only because I refuse to defer normal medical care, the consequences of which have been tragic during the pandemic. I have told clerks “I don’t need a mask”, which is true, and they have backed off. I have turned on my heal at stores that refuse to give on the issue, but like masks themselves, the signs on the doors are usually more for show than anything else. So I walk right past them.
Now, the Biden Administration has decided to provide to the public 400 million N95 masks — on the taxpayer! It’s a waste of time and money. But the timing is incredible, just as the Omicron wave crashes on it’s own. It will be one more worthless act of theatre. But don’t doubt for a moment that Joe Biden, when no one remembers the timing, will claim that this action helped defeat Omicron.
What is the real efficacy of masks in stopping the spread of Covid aerosol emissions? Cloth masks, including bandanas and scarves, are still the most popular masks. Based on casual observation, I suspect most of those masks aren’t washed as frequently as they should be. People hang them from their rear view mirrors for God knows how long. Beyond that, cloth masks tend to fit loosely and protect from aerosols about as well as the disposable medical or surgical masks that are now so common. Which is to say they don’t provide much protection at all.
But can that be? Don’t surgeons think they help? Well yes, because operating rooms can be very splattery places. Besides, it’s rude to sneeze into your patient’s chest cavity. Protection against fine aerosols? Not so much. Oh, but should I double mask? Shut*up!
Face shields are “transparently” useless, offering no barrier against floating aerosols whatsoever except a fleeting moment’s protection against those blown directly into the wearer’s face. Then there are respirator masks: N95 and KN95, which are essentially the same thing. The difference is that KN95s must meet Chinese performance standards rather than U.S. standards. Both must filter and capture 95% of airborne particles as small as 0.3 microns. Covid particles are smaller than that, but the aerosol “beadlets” in which they are swathed may be larger, so the respirators would appear to be a big step up from cloth or surgical masks. R95 and P95 masks are made for protection against oil-based particles. They seem to be better overall due to thicker material and tighter fit with an overhead strap and extra padding.
Measuring Mask Efficacy
A thorough assessment of these mask types is documented in a 2021 paper published in The Physics of Fluids. Here are the baseline filtration efficiencies measured by the authors with an ideal mask fit relative to exhalation of 1 micron aerosols:
These are simply the filtration efficiencies of the respective barrier materials used in each type of mask, as measured by the researcher’s tests. Obviously, cloth and surgical masks don’t do too well. Unfortunately, even the N95 and KN95 masks never fit perfectly:
“It is important to note that, while masks … decrease the forward momentum of the respiratory jet, a significant fraction of aerosol escapes the masks, particularly at the bridge of the nose.”
Next, the authors assess the “apparent” filtration efficiencies of masks measured by relative aerosol concentrations in an enclosed space, measured two meters away from the source, after an extended period. This is a tough test for a mask, but it amounts to what people hope masks can accomplish: trapping aerosols containing bits of crap on material surrounding the nose and mouth, and for many hours. Here are the results:
Cloth and surgical masks don’t do much to reduce the aerosol concentrations. Both the KN95 and R95 masks capture a meaningful share of the aerosols, but the R95 is a bit more effective. Remember, however, that the uncaptured share is a stand-in for the many thousands of virus particles that would remain suspended within the indoor space, so the filtration efficiency, while far superior to cloth or surgical masks, would do little to mitigate the spread of the virus. The KN95-Gap case is a test of a more “loosely fitted” mask with 3 mm gaps, which the authors say is realistic. Under those circumstances, the KN95 is about as good as nothing. Finally, the authors tested a well-fitted KN95 equipped with a one-way discharge valve. While its efficiency was better than cloth or surgical masks, it still performed poorly. The authors also found that various degrees of air filtration were far more effective in reducing aerosol concentrations than masks.
On the subject of mask fit, I quote Dr. Robert Lending, who has regularly chronicled pandemic developments for patients in his practice since the start of the pandemic:
“N95 type masks cannot be worn by men with beards. They must be so tightly fitted that they leave deep creases in your face. Prior to Covid-19, when hospital employees had to wear them for TB exposure prevention, they were told not to wear them for more than 3 hours at a time. They had to be fit-tested and gas leak-tested. … The N95 knockoffs such as the KN95s are not as good. N95 with valves do not protect others from you. There are now many counterfeit N95s for sale. … Obviously, N95s were never meant to be worn for 8-12 hours; and certainly not by youth and school children. If you are wearing an N95 and you can smell anything, such as aroma in a restaurant when you walk in, perfume, cologne, coffee, citrus, foul odors, etc.; then your fit is not correct and that N95 is worthless.”
Another kind of evidence on mask efficacy is offered by randomized control trials (RCTs) in mitigating transmission of the influenza virus across a variety of settings, including hospital wards, schools, and neighborhoods of varying characteristics. A meta-analysis of 44 such RCTs published in the Cochran Library in late 2020 found that surgical masks make little or no difference to the spread of the virus. In a small set of RCTs from health care settings, the authors found that N95 and P95 masks perform about as well as surgical masks in limiting transmission.
An excellent review of research on mask efficacy appeared in City Journal last August. The author, Jeffrey H. Anderson, was fairly awestruck at the uniformity of RCT evidence that masks are ineffective. One well-publicized RCT purporting to show the opposite relied on effects that were negligible. Meanwhile, other research has shown that state-level mask mandates are ineffective at reducing the spread of the virus. Finally, here is a nice “cheat sheet” containing links to a number of mask studies.
Children in many parts of the country are forced to wear masks at school. It’s well-established, however, despite wailing from teachers’ unions, that Covid poses extremely low risks to children. And there is no shortage of evidence that constant masking has extremely negative effects on children. The stupidity has reached grotesque proportions. Now, some school districts are proposing that children wear N95 masks! This is unnecessary and cruel, and it is ineffective precisely because children will be even less likely to use them properly than adults, who are generally not very good at it. From the last link:
“If N95s filter so well, why are respirators an ineffective intervention? Because masking is a behavioral intervention as much as a physical one. For respirators to work, they must be well fitting, must be tested by OSHA, and must be used for only short time windows as their effectiveness diminishes as they get wet from breathing.
“Fit requirements and comfort issues are untenable in children who have small faces and are required to wear masks for six or more hours each day. For these reasons, NIOSH specifically states that children should not use respirators, and there are no respirators that are approved for children. These views are shared by the California Department of public health. Concerns about impaired breathing and improper use outweigh potential benefits. There are no studies on the effectiveness of respirators on children because they are not approved for pediatric use.”
Rip It Off
At this point in the Omicron wave, which appears to have crested, we’re basically dealing with a virus that is less lethal than the flu and, for most people, comparable to the common cold. It’s a good time for the timid to shed their masks, which didn’t help contain the spread of the virus to begin with. And masks do more harm than has generally been acknowledged, especially to children. So stop the bullshit. Take off your mask, and leave it off!