CATER Mask
Decisions
January 5, 2021
Safe Bubble Initiative can be Widely Implemented
in Second Quarter
Combination of CATER and Upgraded Disposable
Masks Supplied Initially
Lots of Sealing Options
Determining Mask Fit and the Amount of
Unfiltered Air
Standard Masks Result in Twice the Leakage When
Worn by Women
An Inefficient Mask can be Worse Than No Mask
_____________________________________________________________________________
Safe Bubble Initiative can be Widely Implemented
in Second Quarter
The
Safe Bubble Initiative can quickly provide the
low COVID risk of lockdowns
but with near normal activity and the use
of tight fitting efficient masks along with
placement of air purifiers and fan filter units
in locations where mask wearing is inconvenient.
Evidence provided in the previous Alerts shows
that the substitution of tight fitting masks for
the average mask being worn today will make a
huge difference.
In this chart the options are rated on the basis
of the most attractive options rated 100% and
the others on a comparative basis. the impact is
the amount of transmission reduced. Cost is the
cost of the product or approach. In the case of
lockdowns the cost is the disruption to the
economy.
Speed rates the ability to quickly
incorporate the product or technology. Fit is
the percentage of air filtered as opposed to
bypassed.
M. Efficiency is the filtration
efficiency of the mask media.
FFU refers to fan filter units.
CATER masks or disposable masks with special
sealing additions can be made available to
everyone within just two months. There are
billions of N95 masks being treated as
disposable. If these are made reusable and tight
fitting with additional straps or seals, they
can provide a temporary solution. Masks are
already being disinfected and reused in hospital
settings. The cleanliness requirements for
public masks are much lower.
The challenge for meeting mask efficiency needs
is the shortage of meltblown media. In the short
term this can be solved by reusing the meltblown
media and using nanofibers and other media
alternatives.
The achievement of a tight fit and efficient
mask media will have maximum impact in the short
term. As shown in the previous alert the
reduction in risk by restricting occupancy to 25
% but allowing ineffective masks results in 25%
of the virus in circulation. When both emitter
and recipient are wearing tight fitting
efficient masks only 1% of the virus is in
circulation.
So a facility in a Safe Bubble
and near normal activity can be up to 25
times less risky than a facility operating with
low occupancy and inefficient masks.
Longer term upgrading HVAC systems with greater
air recirculation and higher efficiency filters
is justifiable.
However, the speed with which this can be
achieved is limited by filter shortages for MERV
13 and higher. However, fan filter units, and
room air purifiers are available in sufficient
quantities to make a real difference in the next
six months.
When the air quality in the safe bubble is
monitored for particulate, CO2, and air flow in
each area assurance of the efficacy of the safe
bubble is affirmed. If entrants to the safe
bubble are screened there is assurance that
safety will not be reduced.
Combination of CATER and Upgraded Disposable
Masks Supplied Initially
Forecasts were previously provided for the mask
needs assuming that everyone wore a reusable
mask for 90 days but that only wealthy people
had access to them until the demand dropped due
to vaccines.
More than nine in 10 U.S. adults (93%) say they
sometimes, often or always wear a mask or face
covering when they leave their home and are
unable to socially distance, including more than
seven in 10 (72%) who said they always do so.
The Philippines have
introduced a new rule forcing everyone in the
country to wear a face shield, as well as a face
mask,
while out in public. Announcing the new rule on
December 15, 2020 , the Philippine government said
that all people would be required to wear both.
Previously, face shields had only been required
in malls and enclosed areas, but now they will
need to be worn at all times outside the house.
Slovakia and Vietnam made face masks compulsory
in many public spaces in the spring of 2000. In
other places, like Hong Kong, masks were
understood to be an effective means to stop the
spread of disease before the coronavirus
emerged. Many businesses mandated them early on,
and many people wore them in public even in the
absence of an official rule. In Japan, where the
government initially faced criticism for not
doing enough to prevent a massive outbreak,
people quickly adapted to everyday mask use,
made easier in part because face coverings were
already in common use.
It is therefore likely that somewhere between 3
billion to 5 billion people will be wearing
masks
through September 2021.
A forecast was compiled based on the assumption
that mask use will be steady
over the 2021-22 period at 3 billion
people wearing masks. Four categories of masks
are plotted. CATER refers to
the comfortable, attractive, tight
fitting, efficient reusable masks which have
been analyzed.
Disposable masks have been divided into
those which are upgraded to provide fit. A
surgical mask with adhesive seals or additional
straps would be an example of an Upgraded
Disposable or Upgrade D masks.
The poor D refers to the typical
inefficient, loose fitting mask now being used.
In the second quarter 500 million people could
be wearing CATER masks. One billion people could
be wearing upgraded disposable masks.
1.5 billion people would still be wearing
the Poor D masks.
The upgraded mask would be a temporary
initiative and would peak in the third quarter.
Volume would then decrease as CATER mask
availability increases.
CATER mask production would grow continuously
and would be worn by 2.8 billion people masks in
the fourth quarter 2022.
At this point in time a significant
portion of the use would be for wildfires, air
pollution, and special health protection.
CATER masks can be worn for up to 90 days. Upgraded disposable masks could be worn for shorter periods. The life of the poor disposable masks is highly variable. In the Alert tomorrow we will convert this forecast of the number of people wearing masks by type to number of masks and revenue.
Lots of Sealing Options
There are lots of sealing options. Subscribers
to the Coronavirus Technology Solutions
can conduct a more complete search than those
with access only to CMD.
Here is an example of a search under both
seal and mask with 60 articles identified
Six pages of results.
Sorted by relevance / Sort
by date
1. McIlvaine
Coronavirus Market Alert
... ,
2020 Dony is a Large Vietnamese Mask Producer
Statistical Studies Showing Advantages of Masks Without ... the
end of the month, we sealed the
first export order from the Middle East ...
Terms matched: 2 - Score: 363 - 7
Jul 2020 - URL:
http://www.mcilvainecompany.com/coronavirus/subscriber/Alerts/2020-07-06/Alert_20200706.html
2. McIlvaine
Coronavirus Market Alert
... 2020
Millions of Lives Saved with Intelligent Mask Program
Millions of Lives at Risk Billions of ... masks can
be fitted for a tight seal but
when worn by general public they are ...
Terms matched: 2 - Score: 360 - 24
Nov 2020 - URL:
http://www.mcilvainecompany.com/coronavirus/subscriber/Alerts/2020-11-24/Alert_20201124.html
3. McIlvaine
Coronavirus Market Alert
... 10,
2020 Overview June 10 Face Mask News
Membrane Mask with
Silver Being Developed by ... resistant
Malleable noseband ensures custom, secure seal Soft
and hypoallergenic Masks feature
three-ply construction for ...
Terms matched: 2 - Score: 350 - 10
Jun 2020 - URL:
http://www.mcilvainecompany.com/coronavirus/subscriber/Alerts/2020-06-10/Alert_20200610.html
4. McIlvaine
Coronavirus Market Alert
... Solutions
October 15, 2020 Experts say Masks are
More Important Now than Vaccines but Fail ... "a
'fit test' tests the seal between
the N95 mask's, or respirator's, ...
Terms matched: 2 - Score: 318 - 16
Oct 2020 - URL:
http://www.mcilvainecompany.com/coronavirus/subscriber/Alerts/2020-10-15/Alert_20201015.html
5. McIlvaine
Coronavirus Market Alert
... is
the Leakage around a Typical N95 Mask Inward
Leakage of Air into Face Masks is ... at
protecting you because they are not sealed.
The main reason surgical masks fail
to ...
Terms matched: 2 - Score: 314 - 6
Nov 2020 - URL:
http://www.mcilvainecompany.com/coronavirus/subscriber/Alerts/2020-11-05/Alert_20201105.html
6. McIlvaine
Coronavirus Market Alert
... Filtration
Resources Needed to Fight COVID Face Masks will
be the Focus on Wednesday at the ... resistance
[?P, cmH2O] across sealed surgical masks (means:
0.1865 and 0.1791 ...
Terms matched: 2 - Score: 306 - 14
Dec 2020 - URL:
http://www.mcilvainecompany.com/coronavirus/subscriber/Alerts/2020-12-14/Alert_20201214.html
7. McIlvaine
Coronavirus Market Alert
... of
COVID Evolving to Resist Vaccines UK Mask Production
Cleanroom Built on Accelerated Schedule Comfort
and ... equipment was being installed the
ceilings were sealed and
the room tested and validated. From ...
Terms matched: 2 - Score: 285 - 12
Nov 2020 - URL:
http://www.mcilvainecompany.com/coronavirus/subscriber/Alerts/2020-11-12/Alert_20201112.html
8. McIlvaine
Coronavirus Market Alert
... has
Delivery Problems Microwave can Sterilize N95 Masks Lots
of Decontamination Investigations Lysol Approved
as a ... is necessary and no matter how
well sealed a
class l cleanroom is it helps if ...
Terms matched: 2 - Score: 284 - 14
Jul 2020 - URL:
http://www.mcilvainecompany.com/coronavirus/subscriber/Alerts/2020-07-13/Alert_20200713.html
9. McIlvaine
Coronavirus Market Alert
... Technology
Solutions August 18, 2020 Some Masks are
Found to Generate Far Reaching Leakage Jets ... .
Only masks that
form a tight seal with
the face were found to prevent the ...
Terms matched: 2 - Score: 278 - 19
Aug 2020 - URL:
http://www.mcilvainecompany.com/coronavirus/subscriber/Alerts/2020-08-18/Alert_20200818.html
10. McIlvaine
Coronavirus Market Alert
... ,
2020 A $450 Billion Attractive Mask Market
Airinum Supplies Masks with
Valves Totobobo Masks ... be
both comfortable to wear and also sealed around
the edges to ensure that air only ...
Terms matched: 2 - Score: 274 - 27
Oct 2020 - URL:
http://www.mcilvainecompany.com/coronavirus/subscriber/Alerts/2020-10-27/Alert_20201027.html
Result Pages: 1 2 3 4 5 6 Next
>>
One of the articles covers the Totobobo
mask which the
manufacturer says can be used for
years because of its filter inserts and
achieves a very tight fit.
A company in Thailand offers a face sealer for
surgical masks which eliminates most of the
leakage.
The Cross Strap Spongy Face Mask Sealer is not
intended to be used alone, it is intended to be
used on top of something else, such as a
surgical mask to seal it.
This may be an awkward solution but as a
temporary option for people in Thailand and
possibly elsewhere in the world it is far better
than a lockdown.
The Banale reusable mask has filter inserts and
emphasizes the tight fit design.
Determining Mask Fit and the Amount of
Unfiltered Air
There has been very extensive testing of filter
media. Fit testing for medical N 95 masks has
been refined and is reliable. Both qualitative
and quantitative tests are being used.
A few companies offering masks to the public
have done fit testing. It is very time consuming
and expensive. There are four variables
·
mask design
·
number of different sizes available
·
individual face shapes
·
activities while using the mask
One company has five different mask sizes and
has conducted fit testing through BSI Group
(British Standards).
Alert November 5 - Surgical Mask Leakage Often
Exceeds 25%
Surgical mask material is fairly good for
trapping viruses, but surgical masks as normally
worn by themselves are not very effective at
protecting you because they are not sealed. The
main reason surgical masks fail to protect
people is air leakage around the mask, whereby
viruses can just easily go around the mask and
into your nose and mouth. The amount of air
going around a mask is known as "total inward
leakage (TIL)" in scientific research.
For example, a study of manikins wearing face
masks showed that typical total inward leakage
often exceeded 25%.
Alert November 16 - University of Tokyo; Net
Efficiency: Cloth 17%, Surgical 47%, N95 79%
Researchers in Japan say they have confirmed
that face masks are effective in both retarding
the spread of viruses and reducing the intake of
them. They used actual coronaviruses and
mannequins to reach that conclusion.
The finding was made by a group led by Professor
Kawaoka Yoshihiro and Project Assistant
Professor Ueki Hiroshi at the University of
Tokyo's Institute of Medical Science.
In their experiments, they placed two mannequins
face-to-face in a laboratory. One was designed
to discharge airborne droplets containing the
coronaviruses. The other had a mechanism
enabling it to take in air, imitating human
breathing.
In one experiment, the researchers put a mask on
the inhaling mannequin. They say the amount of
viruses it absorbed was cut by 17 percent with a
cloth mask and by 47 percent with an ordinary
surgical mask. When they put an N95 medical mask
on the mannequin so it fitted snugly, the amount
declined by 79 percent.
Alert October 15 - University of Chicago -Vogmask
95%, Respro and Totobobo 85%
The 3M masks consistently performed the best in
these tests. The Vogmask performed fairly well,
capturing 95% of pollutants. Big-name masks like
the Respro and Totobobo masks both captured less
than 85% of pollutants.
It’s important to make clear: masks that fit my
face well might not fit other people’s faces
well. However, there is evidence from a broader
population that masks fit most people well. A
scientific study of 3M models on 22 Chinese
people found a median fit score of
99.5%–essentially the same as the top results
from Dr. Saint Cyr and me.
Alert July 28 - 66% Leakage with Chinese Masks
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.
Alert August 14 - With Leaks, Droplets
Temporarily Captured are Later Transmitted
One of the subjects for discussion will be the
measurement of one stop mask efficiency vs
direct flight. An airline passenger can fly from
Seattle to Atlanta where he infects the
recipient. Without a mask the Atlanta recipient
receives the full virus load. But most Seattle
to Atlanta flights stop in Denver. So in this
example with the mask being Denver the full
virus load lands in this hub. But what happens
to it subsequently?
As the millions of deposited viruses start to
evaporate or catch the flight from the hub some
will end up in Atlanta but others will end up in
Chicago and Dallas. In all likelihood an
inefficient mask acts as a hub and distributes
all the virus passengers in a cough in many
different directions.
The original guidance of CDC that masks should
be used primarily to catch the large cough and
sneeze droplets is based on the assumption that
it takes millions of viral particles to infect
someone. Furthermore it was originally presumed
that viruses will not be airborne and if they
are they die quickly. All of these assumptions
have been proven to be inaccurate.
With the one stop or hub and spoke flight
pattern you more than likely have only thousands
or hundreds of virus particles reaching Kansas
City or Albuquerque.
However, if every infected cougher is wearing a
cloth mask there will be many transmitters
generating hundreds or thousands of viral
particles. The recipient may be receiving the
millions of virus particles over time from many
different transmitters.
Some studies in hospitals address the cumulative
effect and conclude that it is significant.
Others establish the long distance travel and
survival of viruses. Other studies show that
some viruses become dormant but are revived by
the moisture in the lungs. This deep penetration
can lead to more serious infection than larger
virus droplets in the nasal passages.
Another way to analyze the problem would be the
example of an infected healthcare worker and an
elderly non infected patient. The worker is with
the patient for an hour and coughs into a mask.
Over the hour the patient may receive as many
virus particles from the worker as he would have
received in the initial cough if the health care
worker had been mask less.
Alert November 25 - Vogmask Shows Inward Leakage
of 2-8% with a Variety of Movements
Fit testing for the public requires a different
system than for healthcare workers. For someone
in a hospital setting there are both qualitative
and quantitative fit testing methods. But they
require tests of individuals.
For masks used by the public the best approach
is to use a panel of people of different sizes,
provide appropriate masks for each and then test
leakage under various conditions. One company
has invested heavily in this approach.
Vogmask has Quantitatively Fit Tested human
subjects to ensure the filtering efficiency is
retained over a series of motions like walking,
head movements, bending over, talking, etc. Here
is a sample of the fit testing on Test Subjects.
The determination of a leakage rating is
therefore more subjective and requires a
different validation approach. An expert
reviewing the Vogmask data would have confidence
that the leakage range is within the 1-8%
range. It is therefore recommended that a
validation group be formed to provide impartial
judgements on data submitted by mask makers
Alert December 3/4 - Face Seal Leakage
Documented for Surgical Masks
The efficiency and face seal leakage
characteristics of two half masks equipped with
particle filters or gas filters, and of two
surgical masks were studied by means of a test
head connected to a breathing machine.
Filtration and leakage were studied as a
function of particle size over a diameter range
of 0.3-10 micron with corn oil aerosol and an
optical particle counter. The filtration
efficiency of the filter materials was good,
over 95%, for particles above 5 micron in
diameter but great variation existed for smaller
particles. The face seal leakage was manifested
as decreased efficiency for large particles and
also for total mass, while the particles in the
micrometer range contained the major part of the
test aerosol mass. The particle number
efficiency diagrams obtained can be used both in
filter material studies and in leak detection of
valves or filter housings
https://pubmed.ncbi.nlm.nih.gov/4014006/
Standard Masks Result in Twice the Leakage
When Worn by Women
Computer modelling by researchers in the US
reveals that standard recommended
face masks have more leaks when used by women.
Photo: Shutterstock
Standard face masks recommended by US health
authorities are not a good fit for women – or
the elderly or thin people, according to a new
study.
Researchers led by Dr Kourosh Shoele at Florida
State University found that masks recommended by
the US Centres for Disease Control and
Prevention to stop the spread of the
coronavirus fit people with masculine
facial features very well.
But “leakage” from the mask of the suggested
size and design doubled when used by women
because the protective equipment was too big.
This was also the case with thin or elderly
users.
“Different mask designs should be recommended
for different categories of people, especially
based on weight, age, and gender,” the team said
in a non-peer-reviewed paper posted on the
preprint site medRxiv.org
Shoele’s team also found that a mask’s fit over
the chin was a problem for people who were
underweight. For the same reason, the elderly
also had a greater gap than the young during
routine daily activities such as talking and
breathing, according to the computer simulation.
Women in the United States are already more
likely than men to wear a face mask, according
to a separate study.
They also do so with greater care. Across the
US, more 55 per cent of women wore masks as
recommended compared with 38 per cent of men,
researchers at New York University and Yale
University said in a paper published in the
journal Behavioural
Science and Policy.
An Inefficient Mask can be Worse Than No Mask
This is a conclusion of an article appearing
last week in the American Institute of
Physics. Air flow patterns when wearing
inefficient masks are such as to cause more
sub-micron particles to penetrate deeper into
the respiratory system.
Pressure and particle motions with and without a
mask. Credit: Jinxiang Xi
In Physics
of Fluids, by AIP Publishing,
researchers from the University of Massachusetts
Lowell and California Baptist University
examined the effect of wearing a three-layer
surgical mask on inspiratory airflows and the
mask’s effects on the inhalation and deposition
of ambient particles in the upper respiratory
airways.
“It is natural to think that wearing a mask, no
matter new or old, should always be better than
nothing. Our results show that this belief is
only true for particles larger than 5
micrometers, but not for fine particles smaller
than 2.5 micrometers,” said author Jinxiang Xi.
(The SARS-CoV-2 virus
that causes COVID-19 is about 0.1 micrometers. —
ed.)
The researchers found that wearing a mask with
low (less than 30%) filtration efficiency can be
worse than wearing none.
They developed a computational face mask model
using a physiologically realistic model of a
person wearing a surgical mask with pleats and
then using numerical methods to track the
particles through the mask. They examined the
behavior and fates of aerosols passing through
the mask, onto the face, into the airway, and,
eventually, where they deposit in the nose,
pharynx, or deep lung.
The model showed a mask changes the airflow
around the face, so that instead of air entering
the mouth and nose through specific paths, air
enters the mouth and nose through the entire
mask surface but at lower speeds.
The lower speed near the face favors the
inhalation of aerosols into the nose, so even
though masks filter out certain numbers of
particles, more particles escaping mask
filtration can enter the respiratory tract.
They found the filtration efficiency of the
three-layer surgical mask can vary from 65%, if
new, to 25%, when used, so wearing a 65% mask
properly will provide good protection but
wearing a 25% filtration mask can be worse than
not wearing one at all.
“We hope public health authorities strengthen
the current preventative measures to curb
COVID-19 transmission, like choosing a more
effective mask, wearing it properly for the
highest protection, and avoid using an
excessively used or expired surgical mask,” said
Xi.
The researchers found the pleats of a surgical
face mask significantly affect airflow patterns,
suggesting that mask shape should also be
considered as an important factor when
estimating mask protection efficiency and
designing new masks. Xi said they will further
study the effects of mask shapes on human airway
protection efficiency.
Reference: “Effects of mask-wearing on the
inhalability and deposition of airborne
SARS-CoV-2 aerosols in human upper airway” by
Jinxiang Xi, Xiuhua April Si and Ramaswamy
Nagarajan, 15 December 2020, Physics
of Fluids.
DOI: 10.1063/5.003458
