NEWS RELEASE May 2020
Mask Policy Review
Should we Rethink our Whole Mask Policy?
Should task # 1 be to protect individuals rather than keep them from being spreaders?
Mask Webinar on June 18 to Launch Debate on Protecting Wearer as Well as Those at Risk
Cambridge has an Efficient and Comfortable Mask but with Valve
Armbrust American Gearing Up to Manufacture Billions of N95 Masks per Year
Draeger has Long Term Contract to Deliver N95 Masks to HHS
CDC Approves Powered Air Purifying Respirators
IQ Mask Uses HEPA Grade Filtration Media
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Mask Policy Review
Should we Rethink our Whole Mask Policy?
Mask policy to combat COVID is based not on protecting the wearer but on protecting others from being infected by the wearer. There is an argument to be made that the emphasis should be the other way around. If everyone is protected then stopping the virus at its source is not so critical. It is appealing to just focus on stopping the source as you would by just turning off a garden hose. But if the water is already part of a rain storm, source control is too challenging. Virus in big cough droplets can be likened to the garden hose whereas virus aerosols can be likened to the rain storm.
We have mounting evidence that at least some of the COVID transmission is through small droplet aerosols or on virus attached to small particles. The argument can be made that the most important safeguard will be a highly efficient N95 or even N99 mask. Here are some examples
- Medical personnel are exposed to thousands of times more COVID than others but they wear N95 or even more efficient masks and avoid infection
- 60 choir members in Washington State attended a 2 hour choir practice but sanitized everything and kept 6 feet apart. 45 of them became infected. If they had worn surgical masks maybe only 25 would have become infected. If they had all worn N95 masks none of them should have become infected.
- At a Southern China restaurant where the air conditioner spread COVID N95 masks could have prevented the spread.
- If those passengers on the Diamond Princess isolated in their cabins and inhaling viruses through the HVAC system had instead roamed the ship in N95 masks they would have been spared.
Should task # 1 be to protect individuals rather than keep them from being spreaders?
What hospital would want to put efficient masks on COVID patients but leave medical personnel without protection? In theory the concept works well. Just control a few patients and then not have to worry about anyone else. In practice the obvious result would be disaster as COVID leaks would soon fell the medical workers. The takeaway is that it is very difficult to prevent COVID from entering the air. The same could be said for the concept that wearing inefficient masks will efficiently capture any virus generated by the wearer Since these masks are rated at very low efficiency on 0.3 micron particles and since they do not fit tightly most aerosols will pass through or around the mask
There are many arguments to be made for and against this new concept. They all depend on facts which are in dispute or not clearly understood. McIlvaine will be conducting a webinar on June 18 to discuss all of the following factors.
Virus Factors
- The size and proliferation of aerosols
- The percentage of virus in aerosols versus larger droplets
- The viral load
- Minimum infectious dose
- Life of virus
- Virus rejuvenation from dormancy
- Creation of aerosols from viruses leaving surfaces
Mask Factors
- Efficiency of various masks in removing viruses
- Various mask media options
- Wash ability
- Efficiency reduction over time or with washing
- Mask fit
- Comfort
- Breathability and oxygen deprivation
- Valve options
- Killing as well as capturing viruses
Wearer factors
- Age and immune response
- Other medical conditions
- Lung function
- Activities
Environment
- Virus load
- Percentage of aerosols
- Humidity
- Air flow patterns
- Benefits of capturing other contaminants
Virus Factors
Size and proliferation of Aerosols. We breathe in millions of particles per minute but must avoid just 10 viral particles. Small particles such as virus aerosols are invisible. This can provide a false sense of safety. In every cubic meter of air we inhale we also inhale 35 million particles greater than or equal to 0.5 microns in diameter. We inhale even more smaller particles in the 0.1 to 0.2 micron range which is the size of the virus.
The following table is designed to rate cleanrooms.
ISO 14644-1 Cleanroom Standards
BS 5295 Cleanroom Standards
There are some reports that the minimum infectious dose for COVID -19 can be as low as 10 viral particles. This means that if just a tiny fraction of the particles we inhale every minute are COVID we can become infected. For comparison purposes a pharmaceutical cleanroom typically is ISO 5. The cleanest operating theaters in hospitals are ISO 4. The semiconductor industry spends billions of dollars per year to reach ISO 3. The task of keeping small particles such as viruses from occupying space is very difficult.
Many of the particles we inhale are long distance travelers. For example mercury emitted from gold mines in Brazil has been traced to the Artic. When a volcano erupted in Iceland the skies turned dark in Europe for weeks. Italian researchers have found COVOD on air pollution particles in the Lombardy region. Another takeaway is that social distancing has limited effectiveness. Viruses travel on cigarette smoke sized particles. So one way to view the task is to think that everyone you encounter is puffing away and you have to avoid even inhaling a few of his smoke particles.
The percentage of virus in aerosols versus larger droplets: Viruses attach to droplets or particles. They are only 0.1 microns in diameter but may be in droplets 20 microns in diameter or larger. Droplets in the 5 micron range can also be generated or can be the result of evaporation of larger droplets. In medical changing rooms in China higher viral loads have been noted. Viruses are also being aerosolized by cleaning the floor or from other surfaces.
Viral Load: The viral load varies by individual and activity. A lusty super spreader singer was able to generate many thousands of aerosols and infect 45 people in just two hours.
Minimum Infectious Dose: There are reports that only 10 viral particles is enough to cause an infection. Other views are that it generally requires a large number of particles over a period of time. Since large cough or sneeze droplets don’t travel far, social distancing is therefore the best way to avoid infection. However, if small numbers of airborne viruses can cause an infection then a whole different approach is needed.
Life of Virus: The virus is known to remain viable for hours in the air and for days on various surfaces.
Virus Rejuvenation from Dormancy: It has now been documented that viruses are not necessarily dead but just dormant as they travel through the air. They can then penetrate the lungs where the moisture revives them.
Creation of Aerosols from Viruses Leaving Surfaces: There are numerous cases tracking aerosols which were originally on surfaces such as floors or clothing.
Mask Factors
Efficiency of Various Masks in Removing Viruses: Masks vary in efficiency depending on the media and the fit. Viruses average 120 nm in diameter but can be entrained in droplets larger than 300 nm. In general the efficiency improves with more media which means higher pressure drop. The meltblown media used with most N95 masks is electrostatically charged which improves capture efficiency.
The pressure drop impacts breathability. It increases as the square of velocity. So where there is lots of leakage such as the surgical mask with the gap below, the actual pressure drop is much lower than 2.5 Pa. this is because much of the air is bypassing the media. It is clear that surgical masks with gaps do not remove a big percentage of small particles. Most homemade masks are even more inefficient. In some cases a heavy cotton fabric is by itself quite efficient but with high resistance it will cause more air to bypass the mask. The takeaway is that the masks being worn by the public do not protect against virus aerosols.
Table 1. Filtration Efficiencies of Various Test Specimens at a Flow Rate of 1.2 CFM and the Corresponding Differential Pressure (ΔP) across the Specimens
The analogy can be made between a garden house and a rainstorm.
If you only want to remove large cough droplets its as easy as dodging a garden hose wielded by a baby. If you want to stay dry in a major storm that is very challenging.
Various mask media options: Surgical masks are made mostly with meltblown polypropylene. The meltblown is sandwiched between two layers of spun bond media. There is an electrostatic effect which improves on the already high efficiency due to the fine fiber matrix. There are some new meltblown designs with claims of even higher efficiency at a given pressure drop.
There are a number of alternative materials which are now available commercially. They include nanofiber membranes which are claimed to have higher efficiency at a given pressure drop. They are also washable. The media is available in large quantities. In the case of Cummins the offering is based on media originally designed for filtering engine air intakes. In the case of Ahlstrom it is the use of surgical drapes. Berry is another supplier diverting media used from other applications.
Efficiency: Some of the newly available media has efficiencies rated at N99 or better. 3M already offers a range of options higher than N95 using meltblowns. The question of a carbon layer and its impact on efficiency also needs to be addressed.
Wash ability: N95 masks with meltblown media can be decontaminated with UV light, H2O2 , or other means. Battelle reports ten time successful reuse of masks decontaminated with H2O2. Masks made with membrane materials can be washed by various means and reused many times. This reuse ability results in a better tight fitting mask with an affordable cost per use.
Efficiency reduction over time or with washing: The support structure as well as the mask media can deteriorate. The ability to separate the media and support structure means that the structure can provide longer term use.
Mask Fit: The mask fit is critical to providing protection. The more expensive reusable masks can provide that fit.
Comfort: N95 masks without valves but with a tight fit are uncomfortable to wear for long periods. The medical worker can endure the discomfort for a shift but it is unrealistic to think that people will wear N95 tightfitting masks without valves throughout the day without serious negative impacts.
Breathability and oxygen deprivation: With a tight fitting N95 mask the quantity of air inhaled is down as much as 25%. Some CO2 is re-entrained in the new breath. Two Korean 14 year olds who were required to run in 1000 meter tests with their masks on died last month on the track. The government has since suspended the requirement.
Valve options: There is a large industry which has flourished for many years. Masks with valves are purchased by those wanting to protect themselves from air pollutants. In China there are Vogmask stores where all they sell are dozens of varieties of highly efficient designer masks. They are equipped with one way valves which allow the air to be exhaled through the valve.
Millions of people have been wearing these valve masks to protect themselves without concern about their potential contamination of others. Why is this not an important model for us to use going forward?
Killing as well as capturing viruses: A number of media designs incorporate silver or other materials which will kill bacteria and viruses.
Wearer factors
Age and immune response: The use of masks by the elderly is conditioned on the breathability. It is unlikely that anyone with reduced lung function or heart problems could wear an N95 mask without a valve. Shouldn’t the type of mask be dictated by this need? Should the elderly be deprived of efficient masks because valves are prohibited? Sacramento says: Masks with valves are prohibited. Lets consider mask recommendations by segment and not as one.
Other medical conditions: Those with impaired immune systems can probably justify an N99 Mask and tight fit. This will require use of a valve. The tight fit is also a function of the valve. If you are blowing air out around the edges of the mask you tend to expand the opening.
Lung function: The lung functions vary among individuals creating an important variable in mask selection.
Activities: Any job function involving physical labor including many meat processing jobs needs to take into account the importance of wearing a mask which does slow down oxygen intake.
Environment
Virus load: The wearing of masks can be tailored to the viral load and therefore the risk. There is a movement to develop a N-80 mask which would be less efficient than the N95 but more efficient than the typical surgical mask. Individuals could have all three mask options available. They could decide where it is most appropriate to not wear a mask or to wear the N80 or N95.
Percentage of aerosols: The danger at any point in time is a function of the percentage of the total viral load which is in the form of aerosols.
Humidity: In general higher humidity deters the virus when it arrives. The virus travels shorter distances in humid air than in dry air where the droplet size is smaller.
Air Flow Patterns: The viral load is in part determined by air flow. This important subject is dealt with in a separate analysis.
Benefits of capturing other contaminants: The coronavirus pandemic will subside at some point in time. There will be uncertainty about when and if it will return. Wearing an N90 mask may become as much a habit as drinking bottled water. Everyone is subjected to high air pollution levels at some point in time during the year. In some countries this is a daily occurrence. But even in others the mask will be justifiable. St Louis was meeting its particulate ambient emission goals and was assumed to be meeting its toxic metal goals which had been shown to track the total particulate. However, when the city installed monitors to directly measure toxic metals, they found spikes on days when the wind blew from the direction of a lead refinery.
Hospital acquired infections cause 1.7 million illnesses and 99,000 deaths per year in the U.S. Patients would be well served to wear N95 masks
Mask Webinar on June 18 to Launch Debate on Protecting Wearer as Well as Those at Risk
A webinar will be held on January 18 at 10:AM CDT to discuss and debate the proposition:
Mask selection should be based on wearer needs first and then on needs of those at risk.
This proposition is in conflict with certain ordinances which prohibit masks with valves. It challenges conventional wisdom. However, the general premise that all individuals if protected by highly efficient masks could lead near normal lives would be of high importance to world economic recovery. The support or rejection of this proposition rests on determination of the following factors
Virus factors
- The size and proliferation of aerosols
- The percentage of virus in aerosols versus larger droplets
- The viral load
- Minimum infectious dose
- Life of virus
- Virus rejuvenation from dormancy
- Creation of aerosols from viruses leaving surfaces
Mask Factors
- Efficiency of various masks in removing viruses
- Various mask media options
- Wash ability
- Efficiency reduction over time or with washing
- Mask fit
- Comfort
- Breathability and oxygen deprivation
- Valve options
- Killing as well as capturing viruses
Wearer Factors
- Age and immune response
- Other medical conditions
- Lung function
- Activities
Environment
- Virus load
- Percentage of aerosols
- Humidity
- Air flow patterns
- Benefits of capturing other contaminants
Insights are encouraged in advance and will be made available at the time of webinar. These insights should address the factors and what is already said about them in the background document. The session will be in a discussion format with each of the factors reviewed as warranted.
Send your comments to Bob McIlvaine This email address is being protected from spambots. You need JavaScript enabled to view it. 847 226 2391.
To register for the webinar Click here
Cambridge has an Efficient and Comfortable Mask but with Valve
The pro mask uses a unique triple filter system which has been tested by Nelson and reaches N99 efficiency levels.
The first layer of the filter system catches larger pollution particles such as dust and PM10. It’s then backed up by the Three-Ply Micro Particulate which stops nearly 100% of smaller particulate matter such as PM2.5 and PM3.0.
The inner filtration layer is made from 100% pure activated carbon cloth, originally developed by the UK Ministry of Defense for chemical, biological, and nuclear warfare protection.
The carbon filter is treated with silver to ensure 99% of harmful pathogens are removed and killed. The filter material is comprised of a series of activated carbon filaments, each about 2,000 nanometers in diameter. Each filament is many times smaller than the typical grain size in standard carbon materials, making the rate of adsorption of pollutant gas much faster and therefore more powerful. It also means that bacteria and viruses are drawn to the filament surface much more efficiently, because there is so much more available surface than in a granular carbon.
The high number of filaments – spun into a yarn and then woven into cloth – makes the speed of adsorption extremely fast in a material that is still easy to breathe through. Not only are molecules such as pollutant gases and endotoxins quickly adsorbed into the pores from a much wider area, but the Van der Waals forces also attract and immobilize on the filament surface much larger particles including bacteria, which often have a negatively charged membrane. Together with the anti-bacterial silver added to the filament surface, the activated carbon cloth traps the bacteria and draws out the gel-like cytoplasm inside – killing it and preventing infection.
Cambridge uses British military technology developed for chemical, nuclear, and biological warfare in the mask that’s manufactured in the UK. But the masks are assembled in Indonesia and China.
Masks Performance Comparison
Armbrust American Gearing Up to Manufacture Billions of N95 Masks per Year
Last week, Armbrust American, announced the close of a $5 million dollar investment round, and the official opening of their Austin, TX-area manufacturing facility.
The factory is currently ramping to produce 1.2 million masks per day, and Armbrust American has plans to scale production to billions annually if needed.
Armbrust American says it can offer masks cheaper than Chinese suppliers, so that American's don't have to choose between Made-in-America quality and price. Individuals can purchase Austin, TX Made Medical Masks for $0.50 on Armbrust's website, with plans to bring prices down as production increases.
"Our Austin, TX lab uses automation to turn raw materials into quality surgical masks," said Lloyd Armbrust, CEO. "And because we are so space efficient, we are even prepared to install unused assembly lines for the next potential crisis; making sure that America is never without the protection we need."
When you click on the website to purchase you receive this message “This is a pre-order for a TEN (10) pack of our N95 masks that are pending NIOSH approval.
The United States has very high standards for what we sell. Because of this, the approval process can take a very long time. We have spent the last five months designing and building our masks, and only recently received FDA Registration. We can now sell our Medical-Grade Facemasks made in Austin, TX--but we cannot move forward with selling our N95 masks until we receive NIOSH approval from the CDC.
The NIOSH approval process for selling N95 masks in the United States can take up to six months.
This order for a 10 pack for $39 will not ship until we receive NIOSH approval which is expected as early as September 2020.
This order will help us gage public interest and allow us to pre buy automated lines for our N95 masks. This means that as soon as we receive approval, we can ship your mask.”
Draeger has Long Term Contract to Deliver N95 Masks to HHS
The U.S. Department of Health and Human Services (HHS) issued an award to Dräger for the supply of National Institute of Occupational Safety and Health (NIOSH) approved N95 respiratory protection masks at the end of March. The contract is part of the recent government announcements concerning the supply of masks. As part of the contract Dräger plans to increase U.S. domestic production of the masks and expand its manufacturing footprint over the course of the contract. Deliveries will take place over the next 18 months with a focus on accelerated supply wherever possible.
“Respiratory protection has been at the core of our capabilities for over 110 years. Our N95 mask design offers superior comfort and breathability and is certified to the NIOSH standard for particle respiratory protection,” said President and CEO for Dräger in North America, Lothar Thielen. “This contract comes in addition to the ongoing work we are doing to protect frontline personnel in the fight against the pandemic. We are humbled to be able to support healthcare professionals and first responders with our Technology for Life, which spans both healthcare and safety applications. In addition we are proud to further increase our U.S. investments and manufacturing base in support of this contract.”
Dräger is an international leader in the fields of medical and safety technology. Our products protect, support, and save lives. Founded in 1889, Dräger generated revenues of almost EUR 2.8 billion in 2019. The Dräger Group is currently present in over 190 countries and has more than 14,500 employees worldwide
CDC Approves Powered Air Purifying Respirators
NIOSH-approved respirators are available in many types, models, and sizes from many manufacturers for a wide variety of uses in many occupational settings. The most common types of respirators in healthcare are N95 filtering facepiece respirators (FFRs), surgical N95 FFRs, and PAPRs.
Of these three options, many healthcare practitioners are the least familiar with PAPRs. A PAPR is an air-purifying respirator that uses a blower to force air through filter cartridges or canisters and into the breathing zone of the wearer. This process creates an air flow inside either a tight-fitting facepiece or loose-fitting hood or helmet, providing a higher assigned protection factor (APF) than the reusable elastomeric non-powered air-purifying half facepiece (half mask) or N95 FFRs. A PAPR can be used for protection during healthcare procedures in which HCP are exposed to greater risks of aerosolized pathogens causing acute respiratory infections.
A PAPR may have a tight-fitting half or full facepiece or a loose-fitting facepiece, hood, or helmet. It has an OSHA APF of at least 25 for loose-fitting hoods and helmets, 50 for tight-fitting half masks, and 1,000 for full facepiece types and some loose-fitting hoods and helmets where the manufacturer’s testing has demonstrated an APF of 1,000.
CDC has published recommendations for HCP respiratory protection and of commonly used NIOSH-approved, FDA-cleared, single-use filtering facepiece N95 surgical respirators. Properly fitted FFR and half facepiece reusable elastomeric respirators are expected to reduce exposures to one-tenth of the concentration that is in the air, based on OSHA’s APF of 10 for these respirator types. All PAPR APFs exceed the APF of 10 for N95 FFR or elastomeric half facepiece respirators.
PAPRs reduce the aerosol concentration inhaled by the wearer to at least 1/25th of that in the air, compared to a 1/10th reduction for FFRs and elastomeric half facepiece air-purifying respirators. OSHA assigns an APF of 1,000 to some PAPRs with hoods or helmets. However, employers must have evidence provided by the respirator manufacturer that testing of these respirators demonstrates performance at a level of protection of 1,000 to receive an APF of 1,000. Absent such evidence, PAPRs with loose-fitting helmets or hoods have an APF of 25. When used properly, PAPRs provide increased protection and decrease the likelihood of infection transmission to the wearer as compared to FFRs and half face reusable elastomeric respirators.
A variety of NIOSH-approved PAPR designs are available. Examples include those with tight-fitting facepieces and loose-fitting hoods or helmets, blower styles, battery types (e.g., Lithium ion, Nickel-Metal hydride, Nickel Cadmium) or over-the-counter disposable batteries, and high efficiency (HE) filters or filter cartridges. HE filters are 99.97% efficient against 0.3 micron particles. A PAPR may have adjustable air flow rates for added comfort and a range of cartridge protections some of which are solely for particulates (HE filters) and others which also protect against chemical gases and vapors that can be used to help protect against hazards associated with the handling of certain hazardous drugs and cleaning/disinfecting operations. The substantial PAPR product diversity provides flexibility to customize protection needed in a healthcare setting.
IQ Mask Uses HEPA Grade Filtration Media
IQAir Mask features a unique exhaust valve design with an ultra-thin valve membrane for low air resistance and immediate air exchange. Many air pollution masks use ineffective material that wears out quickly due to moisture build-up and high filter material resistance – IQAir Mask ensures an even exchange of inhaled clean air and exhaled breaths while reducing moisture and CO2 build-up inside the mask to prevent drowsiness, headaches, or loss of energy.
