COVID-19 is as politically-charged as it is infectious. Early in the COVID-19 pandemic, the WHO, the CDC and NIH’s Dr. Anthony Fauci discouraged wearing masks as not useful for non-health care workers. Now they recommend wearing cloth face coverings in public settings where other social distancing measures are hard to do (e.g., grocery stores and pharmacies). The recommendation was published without a single scientific paper or other information provided to support that cloth masks actually provide any respiratory protection. Let’s look at the data.
The theory behind mask wearing:
- Source control: Cloth mask can trap droplets that come out of a person’s mouth when they cough or sneeze.
- Protection: Personal Protective Equipment (PPE) – only N95 masks
Transmission of SARS-CoV-2
Note: A COVID-19 (SARS-CoV-2) particle is 0.125 micrometers/microns (μm); influenza virus size is 0.08 – 0.12 μm; a human hair is about 150 μm.
*1 nm = 0.001 micron; 1000 nm = 1 micron; Micrometer (μm) is the preferred name for micron
*1 meter is = 1,000,000,000 [trillion] nm or 1,000,000 [million] microns
Droplets
- Virus is transmitted through respiratory droplets produced when an infected person coughs, sneezes, or talks.
- Larger respiratory droplets (>5 μm) remain in the air for only a short time and travel only short distances, generally <1 meter. They fall to the ground quickly.https://www.thelancet.com/journals/lanres/article/PIIS2213-2600(20)30245-9/fulltext
- This idea guides the CDC’s advice to maintain at least a 6-foot distance.
- Small (<5 μm) aerosolized droplets can remain in the air for at least 3 hours and travel long distances (up to 27 ft.).
Air currents…
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