3 ms·

Do they? Where'd you get that data from? I'm sure actual gas masks would work, hopefully, but if you come up with a definition of "mask" that nobody actually u

Do they? Where'd you get that data from? I'm sure actual gas masks would work, hopefully, but if you come up with a definition of "mask" that nobody actually uses and then claim mask mandates work, or even that masks work, then it's the same as admitting they don't really work.

ls15 5y ago
https://www.pnas.org/content/118/49/e2110117118 https://www.pnas.org/content/118/49/e2110117118 > There is ample evidence that masking and social distancing are effective in reducing severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) transmission. However, due to the complexity of airborne disease transmission, it is difficult to quantify their effectiveness, especially in the case of one-to-one exposure. Here, we introduce the concept of an upper bound for one-to-one exposure to infectious human respiratory particles and apply it to SARS-CoV-2. To calculate exposure and infection risk, we use a comprehensive database on respiratory particle size distribution; exhalation flow physics; leakage from face masks of various types and fits measured on human subjects; consideration of ambient particle shrinkage due to evaporation; and rehydration, inhalability, and deposition in the susceptible airways. We find, for a typical SARS-CoV-2 viral load and infectious dose, that social distancing alone, even at 3.0 m between two speaking individuals, leads to an upper bound of 90% for risk of infection after a few minutes. If only the susceptible wears a face mask with infectious speaking at a distance of 1.5 m, the upper bound drops very significantly; that is, with a surgical mask, the upper bound reaches 90% after 30 min, and, with an FFP2 mask, it remains at about 20% even after 1 h. When both wear a surgical mask, while the infectious is speaking, the very conservative upper bound remains below 30% after 1 h, but, when both wear a well-fitting FFP2 mask, it is 0.4%. We conclude that wearing appropriate masks in the community provides excellent protection for others and oneself, and makes social distancing less important. In Germany FFP2/N95/KN95 masks are mandated in many places and situations. Only few people wear them with a tight fit though.
- native_samples 5y ago
  Germany provides a good counterpoint, because some very nearby places differ only in the type of mask mandate. Some places mandate N95 and others don't. This is the result: https://cdn.substack.com/image/fetch/f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fbucketeer-e05bbc84-baa3-437e-9518-adb32be77984.s3.amazonaws.com%2Fpublic%2Fimages%2F69bea0ce-99d7-4c4e-bff7-67f4d00c7fcb_5289x2979.png https://cdn.substack.com/image/fetch/f_auto,q_auto:good,fl_p... No difference.
  - ls15 5y ago
    I agree that the mandates do not work. However, I think that masks technically work if used in the right way, which literally nobody does.

ls15 5y ago

https://www.pnas.org/content/118/49/e2110117118 https://www.pnas.org/content/118/49/e2110117118 > There is ample evidence that masking and social distancing are effective in reducing severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) transmission. However, due to the complexity of airborne disease transmission, it is difficult to quantify their effectiveness, especially in the case of one-to-one exposure. Here, we introduce the concept of an upper bound for one-to-one exposure to infectious human respiratory particles and apply it to SARS-CoV-2. To calculate exposure and infection risk, we use a comprehensive database on respiratory particle size distribution; exhalation flow physics; leakage from face masks of various types and fits measured on human subjects; consideration of ambient particle shrinkage due to evaporation; and rehydration, inhalability, and deposition in the susceptible airways. We find, for a typical SARS-CoV-2 viral load and infectious dose, that social distancing alone, even at 3.0 m between two speaking individuals, leads to an upper bound of 90% for risk of infection after a few minutes. If only the susceptible wears a face mask with infectious speaking at a distance of 1.5 m, the upper bound drops very significantly; that is, with a surgical mask, the upper bound reaches 90% after 30 min, and, with an FFP2 mask, it remains at about 20% even after 1 h. When both wear a surgical mask, while the infectious is speaking, the very conservative upper bound remains below 30% after 1 h, but, when both wear a well-fitting FFP2 mask, it is 0.4%. We conclude that wearing appropriate masks in the community provides excellent protection for others and oneself, and makes social distancing less important. In Germany FFP2/N95/KN95 masks are mandated in many places and situations. Only few people wear them with a tight fit though.

native_samples 5y ago
Germany provides a good counterpoint, because some very nearby places differ only in the type of mask mandate. Some places mandate N95 and others don't. This is the result: https://cdn.substack.com/image/fetch/f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fbucketeer-e05bbc84-baa3-437e-9518-adb32be77984.s3.amazonaws.com%2Fpublic%2Fimages%2F69bea0ce-99d7-4c4e-bff7-67f4d00c7fcb_5289x2979.png https://cdn.substack.com/image/fetch/f_auto,q_auto:good,fl_p... No difference.
- ls15 5y ago
  I agree that the mandates do not work. However, I think that masks technically work if used in the right way, which literally nobody does.