1) Speaking loudly for just one minute can generate over 1,000 virus-containing droplets that remain airborne for more than 8 minutes. 2) Researchers found that diners seated next to an infected person are exposed to more than five times the number of exhaled droplets compared to those farther away. 3) Masks with good filtration and fit, such as double-layer cloth masks, surgical masks, or KN95/KF94 respirators can significantly reduce the outward emission of exhaled droplets and better protect the wearer and others compared to single-layer masks or masks with gaps.

1. Is it Time to
Upgrade Masks?
The widely accepted standard of six feet of
social distance may not be enough.
Restaurant diners contracted coronavirus after
five minutes of exposure from more than 20
feet away without speaking to or touching
common surfaces with an infected out-of-
town visitor. 1
1 minute of loud speech is estimated to
generate at least 1,000 virion-containing
airborne droplets that remain airborne for
more than 8 minutes. Test participants
repeatedly spoke the phrase “stay healthy” in
a loud voice for 25 second bursts. 2
Researchers used a supercomputer to simulate
how droplets of Covid-19 travel and people
seated next to an infected person are exposed
to more than five times the number of
exhaled droplets. 3
Don Clark 2/9/2021
1 Journal of Korean Medical Science
The restaurant air conditioner created a valley of
airflow.
2 The airborne lifetime of small speech droplets,
Proceedings of the National Academy of Sciences:
3Nippon TV News 24 Japan

2. How well a mask works depends on two things:
filtration and fit
CDC: Maximizing Fit for Cloth and Medical Procedure Masks to Improve Performance and Reduce SARS-
CoV-2 Transmission and Exposure, 2021
Don Clark 2/9/2021

3. CDC – Improve How Your Mask Protects You
Don Clark 2/9/2021

4. If you want to protect other people–
wear a mask that has been tested for
protection when breathing, talking
and coughing
If you really want to protect yourself
and others, wear double layers and
ensure a good fit
Speech produces the most droplets during
sustained conversation. 1
Surgical masks or unvented KN95 respirators
reduced the outward emission by 90% and
74% on average during speaking and
coughing. 2
The effectiveness of single layer cotton and acrylic
material masks for coughing and talking is
inconclusive but not great. These masks
increase airborne droplets as much as 400%
according to study 2 or reduce droplets as little
as ~10% according to study 3
Don Clark 2/9/2021
1 Size distribution and sites of origin of droplets, Journal of Aerosol
Medicine
2 Efficacy of masks and face coverings in controlling outward aerosol
particle emission, Nature Research Journals
3 Inward and outward effectiveness of cloth masks, a surgical mask, and a
face shield, medRxiv
Surg.: surgical
KN95: unvented KN95
SL-P: single-layer paper towel
U-SL-T: unwashed single-layer cotton t-shirt
U-DL-T: unwashed double-layer cotton t-shirt
Efficacy of masks and face coverings in controlling outward aerosol particle emission
Inward and outward effectiveness of cloth masks, a surgical mask, and a face shield

5. Copyright 2020 American Medical Association. All Rights Reserved.
From: Evaluation of Cloth Masks and Modified Procedure Masks as Personal Protective Equipment for the
Public During the COVID-19 Pandemic
JAMA Intern Med. Published online December 10, 2020. doi:10.1001/jamainternmed.2020.8168
Consumer-Grade Masks and Improvised Face Coverings
(A) 2-layer nylon mask with ear loops (54% recycled nylon, 43% nylon, 3%
spandex), tested with and without an optional aluminum nose bridge and
filter insert in place, (B) Cotton bandana folded diagonally once “bandit”
style, (C) Cotton bandana folded in a multilayer rectangle according to the
instructions presented by the US Surgeon General, (D) Single-layer
polyester/nylon mask (80% polyester, 17% nylon, 3% spandex) with ties,
(E) Polypropylene mask with fixed ear loops, (F) Single-layer gaiter/neck
cover balaclava bandana (92% polyester and 8% spandex), (G) 3-layer
cotton mask (100% cotton) with ear loops

6. Copyright 2020 American Medical Association. All Rights Reserved.
From: Evaluation of Cloth Masks and Modified Procedure Masks as Personal Protective Equipment for the
Public During the COVID-19 Pandemic
JAMA Intern Med. Published online December 10, 2020. doi:10.1001/jamainternmed.2020.8168
Medical Procedure Mask and Modifications Designed to
Enhance Mask Fit or Comfort for the Wearer
(A) Medical procedure mask with ear loops modified by tying
the ear loops and tucking in the side pleats, (B) Attaching
ear loops to a 3-dimensional–printed “ear guard”, (C)
Fastening ear loops with a 23-mm claw-type hair clip placed
behind the wearer’s head, (D) Placing a ring of 3 ganged
rubber bands over the mask and around the wearer’s ear,
(E) Sliding a 10-inch segment of nylon hosiery over the fitted
procedure mask (F).

7. NPR Hacks And Tips To Make Your Face Mask More
Protective
You can boost
filtration efficiency
by wearing a two-
layer mask with a
pocket for a filter.
The outer layers
should be made of a
tight-weave fabric.
Tie the ear loops into a knot as close
to the edges of the mask as possible,
then tuck the side pleats in to
minimize any gaps that appear along
the edges. This boosts the surgical
mask's filtration efficiency to 60%.
Or use a hair clip to hold the ear
loops tightly at the back of the head.
If you're still single-
masking, just make
sure the one you
wear is as
protective as it can
be.
When the
researchers covered
the surgical mask
with a 10-inch
section of nylon
hosiery, filtration
efficiency surged to
an impressive 80%.
Don Clark 2/9/2021
Consider KN95s and KF94s
KN95 respirators are easy to find these days. KN95s are regulated by the Chinese government to filter out at least 95% of small airborne particles. Beware of fake KN95s.
Lately, the KF94 has also gotten a lot of buzz. The KF stands for "Korean Filter" and the 94 means it's designed to block out at least 94% of small particles. It has side flaps that mold
to the contours of your face and an adjustable band around the bridge of your nose.