McIlvaine Coronavirus Market Ale

BTL N95 Masks Meet All Required Test Protocols

Surgical Mask Leakage is a Major Hurdle to Besting COVID

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Researchers at the University of Nicosia have added insights on aerosol generation of droplets from mask surfaces.

Face mask filters—textile, surgical, or respiratory—are widely used in an effort to limit the spread of airborne viral infections. Our understanding of the droplet dynamics around a face mask filter, including the droplet containment and leakage from and passing through the cover, is incomplete. We present a fluid dynamics study of the transmission of respiratory droplets through and around a face mask filter. By employing multiphase computational fluid dynamics in a fully coupled Eulerian–Lagrangian framework, we investigate the droplet dynamics induced by a mild coughing incident and examine the fluid dynamics phenomena affecting the mask efficiency. The model takes into account turbulent dispersion forces, droplet phase-change, evaporation, and breakup in addition to the droplet–droplet and droplet–air interactions. The model mimics real events by using data, which closely resemble cough experiments.

The paper does touch on the potential for drop penetration but more detail will be requested. However it does show large droplets are aerosolized and penetrate the mask. Others rebound and in the case of surgical masks or cloth masks can then escape through the openings around the mask.

The study shows that the criteria employed for assessing the face mask performance must be modified to take into account the penetration dynamics of airborne droplet transmission, the fluid dynamics leakage around the filter, and reduction of efficiency during cough cycles. A new criterion for calculating more accurately the mask efficiency by taking into account the penetration dynamics is proposed. We show that the use of masks will reduce the airborne droplet transmission and will also protect the wearer from the droplets expelled from other subjects.

However, many droplets still spread around and away from the cover, cumulatively, during cough cycles. Therefore, the use of a mask does not provide complete protection, and social distancing remains important during a pandemic. The implications of the reduced mask efficiency and respiratory droplet transmission away from the mask are even more critical for healthcare workers. The results of this study provide evidence of droplet transmission prevention by face masks, which can guide their use and further improvement.

A recent study focusing on the habits of personal face mask use in Israel found that "most of the public exposes itself to infection with COVID-19 due to wrong use of face masks."

Health experts recommend changing a mask once every two hours. When a mask is used for too long it can be the perfect environment for bacterial growth, especially if after use the mask is put on a table – another great surface for bacteria. Doing so sets up a never ending cycle, perfect for bacteria to thrive in.

The survey found that 90% of the population does not follow the creed of changing their masks every two hours. More than 25% reported changing their mask less than once a day, meaning a good portion of Israelis use the same mask for days at a time, and fewer than 10% of disposable-mask users report using three or more masks daily. Some 20% report changing their mask once a day.

Continuing on disposable masks, over 75% of the population are using surgical masks while the remainder use reusable washable masks.

As it can be seen around the world, not just in Israel, many wearers tend to place the masks on their neck or below their nose when not in "use," whether by force of habit or just flouting regulations. The survey authors note that the neck is a place where germs and viruses tend to accumulate throughout the day in the life of a normal person.

The McIlvaine observation is that if 75% of the population is wearing surgical masks that is considerably more protection than the cloth masks worn by most Americans. On the other hand even surgical masks are poor protection because of leakage. Wearing an N95 mask for longer periods would be much safer. The newest evidence places less transmission from surfaces than from the air.

A Utah company has garnered a lot of attention online for their “microclimate” face masks, which provide protection from the coronavirus by surrounding a person’s head inside a filtered bubble.

“It’s been fun to see people’s reactions,” said inventor Michael Hall. “I will say, you have to be comfortable in your own skin.”

“I think a few people were asking you know, ‘When’s he going to Mars,’ and things like that,” he said.

HEPA filters in the helmet clean the air coming in and going out. Hall came up with the idea while skiing with his family.

“We have the goggles and so I couldn’t see them,” he said. “It really was about that expression, of wanting to be able to look people in the eye and talk to them.”

When the pandemic hit earlier in the year, Hall’s team found another purpose. They’ve run tests, showing how particulate matter gets through cloth masks, then N95s, and finally, through the microclimate’s filters.

“I see people who have got to wear a mask all day, and they’re usually the ones looking at it saying, ‘how do I get that?'” said Hall.

“Kind of like eyeglasses or hats or other wearables,” he said. “Once you have this on for a few minutes, it just kind of disappears into the background.”

Still, when you wear a space-helmet with those fans running, it can have some drawbacks.

Hall said they’ve already had sales in the thousands, with very little marketing.

Slate Magazine Says Airline Case Studies are not a Worry If People Wear Masks.

Air travel has long provoked anxiety in passengers, but even more so after SARS-CoV-2 has taken hold worldwide. In the past several months, scientists and public health experts have emphasized that the risk of contracting the virus is greatest in small, enclosed spaces with many people—and where do people feel more claustrophobic and crammed than an airplane?

So recently, two new case studies of potential coronavirus transmission aboard airplanes immediately made the rounds online, creating buzz about the “dangers” of in-flight COVID transmission. Several outlets uncritically reported the authors’ findings, both published in the U.S. Centers for Disease Control’s journal Emerging Infectious Diseases, which looked at two clusters of suspected coronavirus transmission on flights. While the possibility of plane transmission may sound alarming, neither of these studies tell us much about COVID-19 risks that we didn’t already know.

The first thing to note is that both cases took place on long flights in early March. One case study, led by researchers at Vietnam’s National Institute of Hygiene and Epidemiology, found a cluster of cases on a 10-hour flight from London to Hanoi, which landed March 2. A 27-year-old woman had a fever and was coughing during the flight, and the researchers later found 15 other people on the flight who tested positive for COVID-19. The other study, led by researchers in London and Hong Kong, found that on a 15-hour March 9 flight from Boston to Hong Kong, a couple sitting in business class infected two flight attendants.

The length and timing of these flights introduced potential risks that may not apply to current air travelers. Scientists have long emphasized exposure time as a risk factor; the longer you’re in close proximity to an infected person, the more likely you are to encounter the virus particles they’re shedding. But unlike the passengers in these clusters, most air travelers are not taking 10- to 15-hour flights.

And the timing of these flights —early March—means that they occurred before mask-wearing on planes was compulsory. That’s no longer the case; all major airlines now require passengers to mask up. (A colleague who flew recently told me that on her flight last week, the pilot did not mince words about “blacklisting” any uncooperative passengers.) “Wearing masks makes a huge difference,” says Qingyan Chen, professor of mechanical engineering at Purdue University and a former director of the FAA’s Airliner Cabin Environment Research Center. Lab studies have shown that masks of all materials can be effective at filtering virus particles and decrease the number of particles people expel into the air—all important factors to consider when breathing and talking in close proximity to other plane passengers. Hopefully, the adoption of mask-wearing has prevented more of these clusters from popping up.

While it’s likely these two case studies identified cases in which COVID-19 was transmitted aboard planes, the exact mechanisms of transmissions are not crystal clear. In the Boston-to-Hong Kong case, researchers performed genetic analyses of samples from all four infected people and found a 100 percent match, suggesting that the couple in business class passed on the same strain to their flight attendants. The genome sequencing is convincing, says Lin Chen, director of the Harvard-affiliated Mount Auburn Hospital and president of the International Society of Travel Medicine. But even so, there’s still the possibility that the crew could’ve happened to be exposed to the same strain somewhere besides the flight. With the London-to-Hanoi study, Chen says she also suspects plane transmission was likely, but the causality is even harder to discern, because the researchers did not sequence samples. “Until genome sequencing is done on a lot of these suspected in-flight transmission cases, it’s hard to say for sure.”

Joseph Allen, a researcher at the Harvard T.H. Chan School of Public Health, laid out his doubts about the case study’s causality in a Twitter thread. He points out that based on the timing of some passengers’ symptom onset and what they did immediately after the flight (a few went on cruises!), it’s possible—or even likely—that some of these “flight-associated” cases actually contracted the coronavirus elsewhere, not necessarily on the flight itself.

That’s not to downplay the risks of getting COVID-19 on a plane; it can certainly happen. But the airplane itself is not particularly dangerous, says Purdue’s Chen. In most large airplanes, air circulates through the cabin in five to seven minutes, and then is filtered through a HEPA filter that is 99.97 percent effective at filtering small particles. “The air supply into the cabin is super clean, but that doesn’t mean you have zero risks there,” he says. The biggest risk, as he sees it, is in the moments when passengers might take masks off—like while eating. Chen recommends staggering snack times so that passengers don’t all have their masks off at the same time. “The risk occurs during this period because I talk, I generate droplets, and that goes directly to the people sitting next to me,” he says.

Harvard’s Chen says these studies are helpful confirmation that flight transmission can happen, but agrees that overall, the risk is generally low. First, she points to the number of infected people on these planes: Both carried more than 200 passengers, and the number of potentially infected passengers made up just a small portion of people aboard. And, she says, the fact that few clusters have been reported should be heartening, as well as the reports of cases in which infected people have boarded an airplane without infecting anyone.

BTL N95 Masks Meet All Required Test Protocols

BTL revamped several of their manufacturing facilities to start producing medical-grade respirators. As of September 2020, BTL’s European manufacturing facilities have been producing FFP2 (European equivalent to N-95) flat-fit respirator masks, for both medical professionals and consumers. The respirator masks received both CE marking and FDA EU.

The FLAT-FIT medical respirator is specially designed to provide maximum safety without compromising comfort. The filtration efficiency of an FFP2 respirator is achieved by electrostatically charged microfibers that attract and trap airborne particles. The optimum density of the filter membrane provides reliable protection and low breathing resistance.

• High filtration efficiency

• Approved for use as an FFP2 respirator

• Approved for use against SARS-CoV-2 according to PPE-R / 02.075 version 1

• Bacterial and Viral filtration efficiency ≥ 99.9%

• Average NaCl Filtration Efficiency > 99% according to 42 CFR part 84

• Tested for splash resistance according to EN 14683

MODEL	FLAT-FIT Healthcare Respirator
Filter category	FFP2
EN 14683:2019 + AC:2019	Splash resistance tested
EN 14683:2019 + AC:2019	Bacterial and Viral filtration efficiency ≥ 99.9%
42 CFR part 84	Average NaCl Filtration Efficiency > 99%
PPE-R/02.075 1 version	Approved for protection against SARS-CoV-2
Valve	No

We will be placing special emphasis on assessing the importance of leaks around the edges of surgical masks. We will also be weighing the alternatives from different mask designs to just modifications and additional components.

All the latest evidence shows that much of the COVID transmission is through small aerosols. This means that that any leakage of air around the mask will be dangerous. think of perfume or cigarette smoke.

In terms of the mask preventing the escape of virus the problem is compounded by the temporary capture of large droplets on the mask interior. These droplets evaporate and will create aerosols which will penetrate or escape around the mask periphery. So transmission can take place by four different routes.

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There is a technical difference between a “mask” and a “respirator”. In day to day language we often say mask, when referring to what are technically called respirators.

§ Example – worn during surgery to prevent coughing, sneezing, etc. on the vulnerable patient

§ The vast majority of masks do not have a safety rating assigned to them (e.g. NIOSH or EN)

§ Non-valved respirators provide good two way protection, by filtering both inflow and outflow of air

§ These are designed to protect the wearer (when worn properly), up to the safety rating of the mask

§ The most commonly discussed respirator type is N95. This is an American standard managed by NIOSH – part of the Center for Disease Control (CDC).

§ Europe uses two different standards. The “filtering face piece” score (FFP) comes from EN standard 149:2001. Then EN 143 standard covers P1/P2/P3 ratings. Both standards are maintained by CEN (European Committee for Standardization).

Let’s see how all the different standards compare:

Respirator Standard	Filter Capacity (removes x% of all particles that are 0.3 microns in diameter or larger)
FFP1 & P1	At least 80%
FFP2 & P2	At least 94%
N95	At least 95%
N99 & FFP3	At least 99%
P3	At least 99.95%
N100	At least 99.97%

In our July 28 article we covered an article on Chinese masks which showed that even if the efficiency rating was high, the leakage during normal activity could be 66%. Researchers first tested each mask’s filtration efficiency by drawing airborne diesel exhaust through a section of the material for 30 minutes and measuring the particulate matter and black carbon concentrations on both sides. They also tested four masks on 10 volunteers who were exposed to diesel exhaust in a lab while performing tasks such as talking, sitting, standing, bending over and walking in place.

In the filtration tests, the average particle and carbon penetration ranged from 0.26 percent to 29 percent, depending on the mask material. In the volunteers, the average leakage around mask edges ranged from 3 percent to 68 percent during sedentary tasks and 7 percent to 66 percent in active tasks. Only one mask had an average leakage below 10 percent in both active and sedentary tests.

In our August 4 Alert it was shown that surgical masks were only slightly less efficient than N95 but the study did not take into account leakage.

Comparing no protection (baseline) for 20-min and 30-s exposures, it was predicted that the mean risk of infection was reduced by 24–94% and 44–99% depending on the mask. Risk reductions decreased as exposure durations increased. The greatest reduction in estimated mean risk of infection was for FFP3 masks, which reduced baseline mean risks by 94% and 99% for 20-min and 30-s exposures, respectively (Figure 1). Of non-traditional materials, the vacuum cleaner bag resulted in the greatest reduction in mean risk of infection (20-min exposure 58%, 30-s exposure 83%), while scarves offered the lowest reduction (20-min exposure 24%, 30-s exposure 44%) (Figure 1). However, large variability in filtration,

There is a direct correlation between mask efficiency and infection risk This leads to the conclusion that mask choice can be as important as social distancing and other safety measures. People should be advised not to just wear a mask but to wear the most efficient mask available.

In our September 14 Alert we report on use of masks due to wildfires on the west coast. N95 masks were effective but surgical masks allowed particles to be inhaled through openings around the periphery.