Coronavirus
Technology Solutions
Three-Layered
Masks Most
Effective
Against Large
Respiratory
Droplets
Large Droplets
Do Split and
Penetrate
Inefficient
Masks
School District
of Lancaster PA
will Buy 1300
IsokClean HEPA
Filters.
West Virginia
K-12 Schools
Will Receive
$800 Million
Under Stimulus
Pack
London School
Children Will
Wear Masks
Air Purification
Should a be Part
of an Effective
School Hygiene
Strategy
Students Likely
to Experience
Flu and Cold
Outbreaks
Mask May Become
Standard in the
Future
Pueblo Colorado
Contracts with
Willdan for $76
Million Upgrade
______________________________________________________________________________
Three-Layered
Masks Most
Effective
Against Large
Respiratory
Droplets
The droplet
impacting on the
mask surface is
recorded at
20,000 frames
per second.
These time
sequence images
of droplet
impingement on a
single-,
double-, and
triple-layer
masks show the
total number
count of
atomized
droplets is
significantly
higher for the
single-layer
mask in
comparison with
the double-layer
mask, while only
a single droplet
penetrates
through the
triple-layer
mask. Credit:
Basu et al,
Science
Advances, March
5, 2021
If you are going
to buy a face
mask to protect
yourself and
others from
COVID-19, make
sure it’s a
three-layered
mask. You might
have already
heard this
recommendation,
but researchers
have now found
an additional
reason why
three-layered
masks are safer
than single or
double-layered
alternatives.
While this
advice was
originally based
on studies that
showed three
layers prevented
small particles
from passing
through the mask
pores,
researchers have
now shown that
three-layered
surgical masks
are also most
effective at
stopping large
droplets from a
cough or sneeze
from getting
atomized into
smaller
droplets. These
large cough
droplets can
penetrate
through the
single- and
double-layer
masks and
atomize to much
smaller
droplets, which
is particularly
crucial since
these smaller
droplets (often
called aerosols)
are able to
linger in the
air for longer
periods of time.
Researchers
studied surgical
masks with one,
two and three
layers to
demonstrate this
behavior.
The researchers
reported their
results in Science
Advances on
March 5.
The team notes
that single and
double-layer
masks do provide
protection in
blocking some of
the liquid
volume of the
original droplet
and are
significantly
better than
wearing no mask
at all. They
hope their
findings on
ideal mask pore
size, material
thickness, and
layering could
be used by
manufacturers to
produce the most
effective masks
designs.
Large Droplets
Do Split and
Penetrate
Inefficient
Masks
We have
previously
interviewed
Abhishek
Saha
of UCSD
and learned of
the work they
have been doing
on droplet
evaporation and
conclusions that
viruses in
droplets may
only temporarily
rest on a mask
interior before
proceeding. More
research has now
been completed.
Using a droplet
generator and a
high-speed
time-lapse
camera, the team
of engineers
from the
University of
California San
Diego, Indian
Institute of
Science and
University of
Toronto found
that,
counterintuitively,
large
respiratory
droplets
containing virus
emulating
particles (VEPs)
actually get
atomized when
they hit a
single-layer
mask, and many
of these VEPs
pass through
that
layer. Think of
it like a water
droplet breaking
into smaller
droplets as it’s
being squeezed
through a sieve.
For a 620 micron
droplet—the size
of a large
droplet from a
cough or
sneeze—a
single-layer
surgical mask
only restricts
about 30 percent
of the droplet
volume; a
double-layer
mask performs
better,
restricting
about 91 percent
of the droplet
volume; while a
three layer mask
has negligible,
nearly zero
droplet
ejection. This
video illustrates
the research as
well.
“While it is
expected that
large solid
particles in the
500–600-micron
range should be
stopped by a
single-layer
mask with
average pore
size of 30
micron, we are
showing that
this is not the
case for liquid
droplets,” said
Abhishek Saha,
professor of
mechanical and
aerospace
engineering at
UC San Diego and
a co-author of
the paper. “If
these larger
respiratory
droplets have
enough velocity,
which happens
for coughs or
sneezes, when
they land on a
single-layer of
this material it
gets dispersed
and squeezed
through the
smaller pores in
the mask.”
Schematic
diagram of viral
load getting
trapped inside
the mask layer.
Droplets and
virus are not
drawn to scale.
Basu et al,
Science
Advances, March
5, 2021
This is a
problem. Droplet
physics models
have shown that
while these
large droplets
are expected to
fall to the
ground very
quickly due to
gravity, these
now smaller,
50-80
micron-sized
droplets coming
through the
first and second
layer of a mask
will linger in
the air, where
they can spread
to people at
larger
distances.
The team of
engineers— which
also includes
Professors
Swetaprovo
Chaudhuri from
University of
Toronto, and
Saptarshi Basu
of the Indian
Institute of
Science— were
well-versed in
this type of
experiment and
analysis, though
they were used
to studying the
aerodynamics and
physics of
droplets for
applications
including
propulsion
systems,
combustion, or
thermal sprays.
They turned
their attention
to respiratory
droplet physics
last year when
the COVID-19
pandemic broke
out, and since
then, have been
studying the transport
of these
respiratory
droplets and
their roles in
transmission of
Covid-19 type
diseases.
“We do droplet
impact
experiments a
lot in our
labs,” said Saha.
“For this study,
a special
generator was
used to produce
a relatively
fast-moving
droplet. The
droplet was then
allowed to land
on a piece of
mask
material—that
could be a
single layer,
double, or
triple layer,
depending on
which we’re
testing.
Simultaneously,
we use a
high-speed
camera to see
what happens to
the droplet.”
Using the
droplet
generator,
they’re able to
alter the size
and speed of the
droplet to see
how that affects
the flow of the
particle.
Going forward,
the team plans
to investigate
the role of
different mask
materials, as
well as the
effect of damp
or wet masks, on
particle
attrition.
The district is
fighting the
COVID-19
pandemic by
improving
ventilation in
schools, said
facilities
director Dennis
LaPorte during
the board’s
committee
meeting.
Quote:
“What we have
learned since
the start of
this pandemic is
that the focus
is now on
airborne
transmission,”
he said to the
board. “HVAC
systems can
contribute to
the spread of
the virus.”
What it means:
So far, district
staff is keeping
the air systems
flowing in
buildings at all
times, is
changing filters
regularly, and
is instructing
staff on
strategies to
increase air
movement. The
district is in
the process of
buying 1,300
IsoClean
filtration units
(portable HEPA
filtration
systems that
create negative
pressure
environments by
cleaning 99.9%
of air
particles) and
60 Bi-Polar
Ionization units
for larger
spaces (to kill
pathogens,
viruses and
mold); and of
providing fans
for nonrenovated
buildings.
Federal
Elementary and
Secondary School
Emergency
Relief, or
ESSER, funding —
to counteract
the COVID-19
pandemic — will
cover the
estimated $7
million expense.
Now that
President Joe
Biden has signed
the stimulus
package into
law, millions of
dollars of
funding is
expected to flow
into West
Virginia's
education to
help deal with
the pandemic's
impact.
Roughly $800
million of the
relief funding
are earmarked
K-12 schools in
the Mountain
State. There's
just under $200
million to be
dedicated for
West Virginia's
colleges and
universities as
well.
WVVA spoke with
the State School
Superintendent
W. Clayton Burch
about what this
money will mean
for the
education system
in the Mountain
State.
"We now know
that the new
normal may
include upgrades
to HVAC systems.
We know the new
normal is going
to be more
support for
mental health
and more social
and emotional
(health). We
know that
thousands upon
thousands of
children (have)
found themselves
behind
academically
during the
pandemic and
those supports
are going to be
essential. So
these dollars
are very much
needed for the
state of West
Virginia."
W. Clayton
Burch, State
Superintendent
of West Virginia
Schools
As children
return to
classrooms next
week, official
government
guidance
recommends
primary school
pupils need
not don face
coverings.
However, a London
council has
advised the 56
primaries under
its control that
masks should be
worn by children
as young as
four. The
government says:
“The Department
for Education
are in contact
with the local
council on that
matter.”
In general, data
suggests that
children up to
the age of 18
experience lower
rates of
Covid-19-related
hospitalization
and death
compared with
all other age
groups. While
all children are
susceptible to
and can transmit
the virus that
causes Covid-19,
younger children
appear to be
less susceptible
to infection and
when infected
less likely to
spread the
disease than
older children
and adults.
Last week, the
government
announced plans
for the full
reopening of
schools on March
8th alongside a
suite of
measures
designed to
enhance Covid
safety –
including
twice-weekly
testing and a
recommendation
to wear face
coverings in
classrooms for
secondary pupils.
The World Health
Organization
also recommends
that only
children aged 12
and over should
wear a face
covering under
the same
conditions as
adults.
Air purifiers
provide maximum
protection all
year long—not
just when it’s
too cold to open
the windows.
A new report
published by Harvard
T.H. Chan School
of Public Health recommends
using air
purifiers to
scrub
viral
droplets out of
the air.
Harvard’s
guidance states,
“For improving
indoor air
quality in the
classroom, we
recommend
prioritizing
control
strategies —
ventilation,
filtration,
supplemental air
cleaning — and
targeting a
combined 4-6 air
changes per hour
(ACH) for
classrooms
through any
combination of
these
approaches.”
However, not all
purifiers are
the same. You’ll
want a filter
that either
meets or exceeds
ratings by the
American Society
of Heating,
Refrigerating
and
Air-Conditioning
Engineers
(ASHRAE).
MERV-13 filters
meet the bare
minimum.
However, HEPA
filters come
with an
exceptional
filtration
quality that
beats what most
school systems
currently have
in place.
For instance, AeraMax
Pro commercial
grade air
purifiers use a
four-stage
filtration
process and have
True HEPA
filters that
capture 99.97%
of all airborne
contaminants,
including
airborne
viruses. These
air purifiers
for schools also
prove effective
in reducing
airborne
concentrations
of influenza A
(H1N1) aerosol.
In lab tests,
the virus
reduced by 99.9%
within only 35
minutes of
turning on the
AeraMax Pro
unit.
When many
students in the
United States go
back to
in-person
learning this
fall, parents
and school
administrators
may have to
contend with an
unexpected
infectious
disease problem:
more colds than
usual.
That’s at least
the caution coming
from researchers
in Hong Kong,
who published a
study last week
detailing a
spike in common
colds after
students
returned to
classrooms in
the fall,
following nearly
a year of remote
learning.
Specifically,
the researchers
reported almost
seven times more
large outbreaks
of acute upper
respiratory
infections
(involving 20
people or more)
compared with
those recorded
in 2017, 2018
and 2019
combined.
“Normally, we
don’t think of
them as a real
public health
challenge,”
Benjamin
Cowling, one of
the study’s
authors and an
epidemiologist
and
biostatistician
at the
University of
Hong Kong School
of Public
Health, said of
common colds.
But it can be tough
to distinguish
the symptoms of
a cold from
those of
Covid-19,
especially in
kids. And if
colds start
spreading
through schools
in the United
States, children
may be sent home
until they have
been tested for
the coronavirus.
They may even
have to return
to remote
learning.
Here’s what
happened to
students abroad,
and what it
might mean for
kids in the
United States.
In late January
2020, as the
spread of the
coronavirus
increased,
schools in Hong
Kong closed and
began teaching
students
remotely.
Schools reopened
in late May, but
then closed
again in July
through late
September
because of a
surge of cases
of Covid-19.
During the last
week of October,
after schools
reopened once
more, the Hong
Kong Centre for
Health
Protection
received reports
of a surge in
respiratory
infections in
kindergartens,
child care
centers, nursery
schools, primary
schools and
secondary
schools.
By the end of
November,
schools had
reported 482
outbreaks of the
common cold,
mostly in
children up to
and including
primary school
age. Researchers
defined these
types of
outbreaks (which
were classified
differently from
the 81 larger
ones) as at
least three
students in a
class developing
two or more
symptoms —
cough, runny
nose, fever or
sore throat —
within the span
of four days.
Some experts
think that the
spike in cases
may have simply
been a result of
more people
paying attention
to every cough,
sniffle and
runny nose last
fall. “These
children were
likely being
tested at a far
higher rate than
would normally
occur outside of
a pandemic,”
said Dr. Ilan
Schwartz, an
infectious
disease
physician at the
University of
Alberta in
Canada.
But Dr. Cowling
said that the
spike in colds
that occurred in
Hong Kong in the
fall seemed much
higher than the
increase that
was seen in
years past. “It
did seem like
there were an
unusual number
of children in
hospital with
rhinoviruses,”
he said,
referring to the
viruses that
cause most
common colds.
And the doctors
he has spoken
with have told
him the
infections
“seemed to be a
bit more severe”
than usual, too.
In a
correspondence published
in The Lancet in
December,
researchers from
the United
Kingdom noted
something
similar — cold
viruses spiked
in adults in the
two weeks after
children
returned to
school last
fall,
emphasizing that
children are the
primary drivers
of transmission
of cold viruses
to adults.
What could have
been going on.
At this point,
immunologists
can only
speculate as to
why colds surged
after schools
reopened in Hong
Kong.
What really
surprised Dr.
Cowling was that
colds spread
despite the
strict
virus-prevention
measures at
schools. In Hong
Kong, students
spend only half
a day at school,
and they avoid
eating lunch
together. They
also wear masks
all day and sit
at distanced
desks. “Somehow,
the common colds
were breaking
through those
measures,” he
said.
What a
difference a
year makes.
Prior to March
of 2020, if you
didn’t work in a
hospital setting
or on a
construction
site, it’s
unlikely you had
ever worn a face
mask. Now, we
own them by the
dozens—a grab
bag of KN95s and
bandanas,
surgical masks,
and
floral-printed
fabric
coverings. Such
is life during a
global pandemic.
But when the
grip of COVID-19
eases, will
these shields
leave with it?
While experts
urge caution, a
lucky few are
finding their
pandemic
protocols
already easing.
On March 8, the
US Centers for
Disease Control
and Prevention
published new
guidelines that
say those who
have been fully
vaccinated
(that’s two
weeks after the
second Moderna
or Pfizer shot,
or two weeks
after the
one-shot Johnson
& Johnson
vaccine) can see
other
fully-vaccinated
people unmasked
and indoors.
Only 32 million
Americans—or
roughly 9.7
percent of
the
population—were
fully vaccinated
as of March 10.
But that number
will continue to
grow in the
coming months,
especially if
the Biden
administration
fulfills its
promise to
prepare enough
vaccines for
every adult by
the end of May.
From there,
reaching that
coveted herd
immunity will be
a matter of
distribution
(and public
acceptance).
Despite these
hopeful
scenarios, risks
remain. New
COVID-19
variants
continue to pop
up in every
corner of the
globe, which
could render
current vaccines
less effective
in fighting off
infection.
Epidemiologists
expect case
numbers
to continue
rising through
the spring. And
while Anthony
Fauci says he
will give his
daughter “a big
hug” when she
too is
vaccinated, the
world-famous
immunologist has
also made it a
point that
Americans may
need to wear
masks until
2022 in order to
stay truly safe.
Wearing a mask
might have been
a novelty for
Americans to get
used to this
past year, but
their
large-scale use
isn’t new. Face
coverings have
been a popular
public health
measure in East
Asia for more
than a
century. According
to MIT historian
Emma J. Teng,
“[masks seem] to
have arisen with
the 1918
influenza
pandemic,
becoming
commonplace
first in Japan.”
But their use
accelerated
after a 2002
outbreak of
another
coronavirus
known as SARS.
Now,
they’re commonplace in
countries like
China and Korea,
too—something
people wear as a
courtesy to
others if they
feel sick, or
even as a
defense against
environmental
pollution.
Perhaps because
SARS never made
its way to
America on a
population-scale,
face masks never
made their way
into American
popular culture.
It didn’t help
that early in
the COVID-19
pandemic, many
public health
officials in the
US advised
against wearing
masks. Only on
April 3, 2020,
did the CDC
recommend cloth
face masks as a
way to protect
other people, if
not the wearer
themselves.
There were many
reasons for not
recommending
universal mask
wearing. At
least one was
scientifically
sound: At the
time, there was
little evidence
to definitively
say masks could
stop COVID-19
transmission,
says Monica
Gandhi of the
University of
California, San
Francisco,
School of
Medicine. In
fact, most of
what we knew at
that point came
from research on
mannequins—not
real live
humans.
Willdan Group,
Inc. announced
that Pueblo
County School
District 70
(Pueblo D70) has
selected Willdan
as the
design-build
lead for
facility
improvements
totaling up to
$76 million.
This is a
progressive
design-build
contract that
will be paid as
a series of fees
and executed
amendments.
Pueblo D70 has
committed a
first fee of
$1.4 million to
pay for design
and
pre-construction
work up until
the execution of
the first
amendment.
Willdan will
provide
engineering and
construction
management to
update 19
schools and four
district
buildings.
Willdan helped
the Pueblo D70
secure a BEST
grant and a
voter-approved
bond measure
which will be
used to fund
these latest
upgrades. A
majority of the
funds will go
toward major
mechanical,
electrical, and
plumbing
upgrades, and
$6.3 million
will be devoted
to infection
control,
COVID-19
mitigation
measures, and
districtwide
security
upgrades.
These projects
are scheduled to
begin in the
summer of 2021.
Scopes of work
include minor to
major sitework
on parking lots,
sidewalks, and
drainage; roof
replacements and
repairs; new
windows and
doors; and
classroom
remodels and
improvements
such as new
ceilings or
flooring.
“The District
took an
important step
when we created
a facility
master plan
together,” said
Tom Brisbin,
Willdan’s CEO
and Chairman.
“We’re pleased
to be here now,
turning that
plan into real
projects that
will benefit
local students
and teachers for
years to come.”
Willdan began
working with
Pueblo D70 in
2016 to support
the development
of a
district-wide,
15-year master
plan. In 2018,
Willdan
delivered
energy-efficient
upgrades to fund
core
infrastructure
needs for the
district through
an energy
performance
contract.
Pueblo County
School District
70 is located in
Pueblo,
Colorado. It was
consolidated
from 34 smaller
school districts
in 1950 and is
the second
largest (by
geographical
size) school
district in the
state of
Colorado. Pueblo
D70 educates
over 8,000
students from
all over Pueblo
County.
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