locked Re: [ap-ug] To mask or not to mask, that is the question
To add, data from 3M "Respiratory Protection for Airborne Exposures to Biohazards, Technical Data Bulletin Release 5, June 2020 #174" and "Respirators and Surgical Masks: A Comparison Technical Bulletin May, 2020 Revision 4" offers that a standard surgical mask is not considered reliable protection from respiratory infections. They do not filter the virus and they do not fit the face properly with gaps around the nose. Additionally, they are designed to be used in a sterile field like an operating room. They might help with "big chunks" from coughing and sneezing, but not for virus "floating" in the air, or airborne transmission Of course a bandanna or some such is about useless. They do offer than an N95 respirator will filter adequately. Also, OSHA publication "Hospital Respiratory Protection Program Toolkit Resources for Respirator Program Administrators, May 2015" offers the same conclusions in regards to surgical masks and respirators.
Mike J. Shade
Mike J. Shade Photography:
In War: Resolution
In Defeat: Defiance
In Victory: Magnanimity
In Peace: Goodwill
Sir Winston Churchill
Already, in the gathering dusk, a few of the stars are turning on their lights.
Vega, the brightest one, is now dropping towards the west. Can it be half
a year since I watched her April rising in the east? Low in the southwest
Antares blinks a sad farwell to fall...
Leslie Peltier, Starlight Nights
International Dark Sky Association: www.darksky.org
email@example.com [mailto:firstname.lastname@example.org] On Behalf Of uncarollo2
<chris1011@...> via groups.io
Yes, maybe a fine point.
I wear one not for my own protection because breathing in doesn't prevent my getting a lung full of critters. My mask is for the protection of other people so that my phlegm and snot doesn't spray into the air when i sneeze or cough.
Our company was shot down for 2 months because of governor's orders, but now we are all working again. None of our crew has caught the virus, all of us wear our masks here at work when we have to interact or are within 10 ft of each other. Our small operation cannot survive if we get sick, so the mask is a small inconvenience.
Just heard the governor may shut our state down again because of a surge of rising cases. Hope not because right now we are going gang busters and want to produce and ship product. Our competitors overseas have no restrictions now and are eager to put US companies out of business. Is that enough reason to don a mask in public? I hope so.
From: ROBERT WYNNE <robert-wynne@...>
To: email@example.com; Roland Christen via groups.io <chris1011@...>; firstname.lastname@example.org <email@example.com>
Sent: Sat, Aug 1, 2020 5:15 pm
Subject: Re: [ap-ug] To mask or not to mask, that is the question
Maybe this is putting too fine a point on topic without any humor; but from
N95 masks are designed to remove more than 95% of all particles that are at least 0.3 microns (µm) in diameter. In fact, measurements of the particle filtration efficiency of N95 masks show that they are capable of filtering ≈99.8% of particles with a diameter of ≈0.1 μm (Rengasamy et al., 2017). SARS-CoV-2 is an enveloped virus ≈0.1 μm in diameter, so N95 masks are capable of filtering most free virions, but they do more than that. How so? Viruses are often transmitted through respiratory droplets produced by coughing and sneezing. Respiratory droplets are usually divided into two size bins, large droplets (>5 μm in diameter) that fall rapidly to the ground and are thus transmitted only over short distances, and small droplets (≤5 μm in diameter). Small droplets can evaporate into 'droplet nuclei', remain suspended in air for significant periods of time and could be inhaled. Some viruses, such as measles, can be transmitted by droplet nuclei (Tellier et al., 2019). Larger droplets are also known to transmit viruses, usually by settling onto surfaces that are touched and transported by hands onto mucosal membranes such as the eyes, nose and mouth (CDC, 2020). The characteristic diameter of large droplets produced by sneezing is ~100 μm (Han et al., 2013), while the diameter of droplet nuclei produced by coughing is on the order of ~1 μm (Yang et al., 2007). At present, it is unclear whether surfaces or air are the dominant mode of SARS-CoV-2 transmission, but N95 masks should provide some protection against both (Jefferson et al., 2009; Leung et al., 2020).