Surgical, N95 masks block most particles, homemade cloth masks release their own

Laboratory tests of surgical and N95 masks by researchers at the University of California, Davis, show that they do cut down the amount of aerosolized particles emitted during breathing, talking and coughing. Tests of homemade cloth face coverings, however, show that the fabric itself releases a large amount of fibers into the air, underscoring the importance of washing them. The work is published today (Sept. 24) in Scientific Reports.

Without a mask, talking (reading a passage of text) gave off about 10 times more particles than simple breathing. Forced coughing produced a variable amount of particles. One of the volunteers in the study was a superemitter who consistently produced nearly 100 times as many particles as the others when coughing.

In all the test scenarios, surgical and N95 masks blocked as much as 90 percent of particles, compared to not wearing a mask. Face coverings also reduced airborne particles from the superemitter.

Homemade cotton masks actually produced more particles than not wearing a mask. These appeared to be tiny fibers released from the fabric. Because the cotton masks produced particles themselves, it's difficult to tell if they also blocked exhaled particles. They did seem to at least reduce the number of larger particles.

Someone already had. That study was suppressed back in March 2020. In fact it was retracted and all signs of it disappeared. This is not a new study nor is it a second one but one of many that have been suppressed. Only this instance it got out. Now did you see the Japanese study that said face shields do not work?

Also a study was done on hand sanitizer. Hand sanitizer doesn’t do what most think it does. Unless someone never touches anything ever including themselves, hand sanitizer is useless.

Anti-bacterial soap is useless as well. Unless the soap has iodine in it, it is useless as a anti-bacterial soap.

All have been studied to found useless before COVID.

And to prove my point an article from 2019”

Hand sanitizer shown less effective than hand washing against flu
Filed Under: Influenza, General
Stephanie Soucheray | News Reporter | CIDRAP News | Sep 19, 2019
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Hand sanitizer use
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A new study from Japanese researchers challenges the idea that ethanol-based disinfectants are effective at completely destroying influenza A viruses quickly in all situations. The study was published yesterday in mSphere.

In a series of tests, the researchers from the Kyoto Profectural University of Medicine found that ethanol-based disinfectants, or hand sanitizers, would have be in contact for at least 4 minutes with the influenza A virus before killing it, a much longer duration than typical use. After 2 minutes of use, the virus was still active.

Mucus barrier
The reason ethanol-based disinfectants might not be as useful as previously thought has to do with the mucus that surrounds droplets of the influenza A virus. The mucus acts as a hydrogel and protects the virus from the ethanol, the investigators reported.

“We found that the protective effect of mucus is stronger than expected,” said Ryohei Hirose, MD, PhD, a lead author of the paper. Hirose explained that the mucus provides a protective coating for the virus and cannot be deactivated by ethanol-based disinfectants until the mucus is totally dry.

The finding could be a game-changer for healthcare settings, where nurses and doctors often rely on quick uses of hand sanitizers between patients. Currently, the US Centers for Disease Control and Prevention (CDC) and the World Health Organization recommend hand hygiene practices that include using ethanol-based disinfectants for 15 to 30 seconds.

“In a realistic medical setting, a sufficient time interval cannot be secured between treatments, and the next patient’s treatment is performed immediately after the current patient’s treatment in many cases,” the authors wrote.

Those recommendations likely come from previous studies that found ethanol-based disinfectants effective in killing flu, which simulated dried mucus scenarios. When mucus is dry, influenza is inactivated within 30 seconds. When the virus was contained in saline, ethanol-based sanitizers also worked in 30 seconds.

Hand washing overcomes mucus
Hirose told CIDRAP News that hand washing, even without using soap, was able to deactivate the influenza A virus within 30 seconds, even when mucus was still wet.

“In our study, the hand washing was done without any soap,” Hirose said. “Even hand washing without soap is effective against influenza viruses. Of course, hand washing with soap is also effective, and further increases in disinfection effects are expected.”

That jibes with CDC advice, which states, “Washing hands with soap and water is the best way to reduce the number of microbes on them in most situations. If soap and water are not available, use an alcohol-based hand sanitizer that contains at least 60% alcohol.”

Hirose had no recommendation on the relationship between soap ingredients and virus inactivation.

See also:

Sep 18 mSphere study

Sep 18 American Society for Microbiology press release

CDC Q&A on hand sanitizer use

Nonpharmaceutical Measures for Pandemic Influenza in Nonhealthcare Settings—Personal Protective and Environmental Measures

Abstract: There were 3 influenza pandemics in the 20th century, and there has been 1 so far in the 21st century. Local, national, and international health authorities regularly update their plans for mitigating the next influenza pandemic in light of the latest available evidence on the effectiveness of various control measures in reducing transmission. Here, we review the evidence base on the effectiveness of nonpharmaceutical personal protective measures and environmental hygiene measures in nonhealthcare settings and discuss their potential inclusion in pandemic plans. Although mechanistic studies support the potential effect of hand hygiene or face masks, evidence from 14 randomized controlled trials of these measures did not support a substantial effect on transmission of laboratory-confirmed influenza. We similarly found limited evidence on the effectiveness of improved hygiene and environmental cleaning. We identified several major knowledge gaps requiring further research, most fundamentally an improved characterization of the modes of person-to-person transmission.

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