I don't think that's true. Face masks, especially the kind designed to filter air, reduce how many particles from the air get into your lungs and airways.

IIRC the studies used to make that argument were using data from respiratory diseases other than covid, which are different in that you only get infected when stuff gets deep in your lungs, which is going to be the very smallest particles that will not end up getting filtered before then by landing on the inside of your throat etc. That might mean that masks are less effective, since they don't filter the very smallest water droplets quite as well. But it doesn't apply to covid because with that disease infection isn't as localized.

There isn't a practical case for why masks would not make a difference. You block particles containing the virus, you reduce chance of infection.

Edit: Also, here's a snippet from an article a few clicks away from the OP article:

Epidemiological investigations have helped quantify the benefit of mask wearing to prevent the spread of SARS-CoV-2 (Table; Supplement). At a hair salon in which all staff and clients were required to wear a mask under local ordinance and company policy, 2 symptomatic, infected stylists attended to 139 clients and no infections were observed in the 67 clients who were reached for interviewing and testing. During a COVID-19 outbreak on the USS Theodore Roosevelt, persons who wore masks experienced a 70% lower risk of testing positive for SARS-CoV-2 infection.4 Similar reductions have been reported in case contact investigations when contacts were masked5 and in household clusters in which household members were masked.6

[+] EatYouWell@lemmy.world -7 points 11 months ago (3 children)

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[–] chicken@lemmy.dbzer0.com 20 points 11 months ago* (last edited 11 months ago)

You said they "don't do much", which isn't true. The virus might be smaller, but most of the infectious particles are larger than the size of a single virus. Quantity you're breathing in makes a difference too.

[–] solrize@lemmy.world 17 points 11 months ago* (last edited 11 months ago)

N95 masks have an electrstatic layer that removes particles (such as viruses) that are much smaller than the mask pores. The size of the pores is almost immaterial at that scale.

Also, Covid is an aerosol virus, not droplets. The difference is that droplets are large enough to fall to the ground due to gravity, while aerosols linger in the air like smoke. The idea that it was droplets led to the idea of 6 foot social distancing, which would give the particles time to fall to the ground. But that doesn't work. You really need filtration, such as masks and/or HEPA filters. UVC light is also showing some promise for killing the virus in the air, but N95's are tried and true.

[–] Zaktor@sopuli.xyz 4 points 11 months ago

This is misinformation. Masks are rated based on 0.3 micron particles because that's the size that's hardest to filter. Smaller particles are actually more likely to be filtered due to how they move.

https://www.safetyandhealthmagazine.com/articles/20459-osha-updates-faqs-to-address-particle-sizes-and-n95s

The “N95” classification means respirator filters remove at least 95% of “very small” particles (around 0.3 microns in diameter) from the air, OSHA explains, adding that some people have claimed incorrectly that the virus is about 0.1 microns in size. Further, when the virus becomes airborne via an infected person talking, coughing or sneezing, those particles contain more than the virus – they also include water or mucus. Those larger particles are too big to pass through an N95 respirator filter, while electrostatic charge attracts the particles to the fibers in the filter.

“In addition, the smallest particles constantly move around (called Brownian motion), and are very likely to hit a filter fiber and stick to it,” the agency states.