Yes, they do:
Good laymans summary of the science behind mask-wearing:
A second laymans article on the science behind mask-wearing:
https://www.bbc.com/future/article/20200504-coronavirus-what-is-the-best-kind-of-face-mask
Particle sizes stopped by masks:
https://pubs.acs.org/doi/10.1021/acsnano.0c03252
Composition of saliva (the microdroplets generated by coughs and sneezes):
https://www.thejpd.org/article/S0022-3913(01)54032-9/fulltext
Size distribution of microdroplets generated by sneezing:
https://royalsocietypublishing.org/doi/10.1098/rsif.2013.0560
More about droplets and aerosols:
https://first10em.com/aerosols-droplets-and-airborne-spread/
Still more about droplets and aerosols:
https://www.ncbi.nlm.nih.gov/books/NBK143281/
And still more about droplets and aerosols:
https://www.ncbi.nlm.nih.gov/books/NBK143281/
Positive pressure face mask (for hypoxia sufferers):
https://cleanspacetechnology.com/us/cleanspace2/
All of that is hogwash and fear mongering !
Most aren't "fitted" properly and average about 75% effectiveness so they fail at least 25% of the time.
A surgical mask, about 70% of the outside air moves through the mask and about 30% travels around the sides
Fabric masks also allow air in around the sides, but lack non-woven, moisture-repelling layers. They impede only about 2% of airflow in
https://www.livescience.com/are-face-masks-effective-reducing-coronavirus-spread.html
There's just as many references that say they don't work. Unless it's a properly fitted HEPA type filer it's useless so all these folks running around stores with homemade mask are just fooling themselves not to mention unless they have a face shield to protect their eyes then it's even more irrelevant. To be truly protected you'd need a real mask:
Great links. But you are replying incorrectly. Maddog was saying that the masks don’t keep the particles out, and this is also mostly correct.
Worse, the masks actually concentrate the particles that you do aspirate and the mask itself has negative consequences beyond the concentration of CO2 and impairment of breathing for the individuals wearing specific types of masks (Home made mostly) (The lightweight surgical masks have much less impact but this is because they are very thin and very light weight which.. is about them being designed to accomplish the goals laid out in the papers you cite.)
The mask doesn’t protect you, and wearing it for significant periods increases your risk and the complications you will be facing.
The studies you are citing are all about containing the particles that you aspirate so that they are not expelled into the air around you if you are sick.
All fine and good. But, in the wild you get to see in the US what happens when you attempt to force people to wear these things. First, they don’t. Second, they wear them wrong.. mostly around their neck, or with their nostrils out.. and they play with them continuously because the plume of breath is forced up the face into the eyeballs.. fogging glasses or simply causing irritation.
I used to be a huge advocate of masks until I notice that only about 50% of wearers actually used them correctly, and those that did clearly were suffering. When you couple this with a very uncertain cost benefit ratio and increasing harm over time, this rush to masks was wishful thinking.
Surgeons wear these masks to protect the patients from casual exposures to what they brought into the room. They are purposely made exceptionally cheap so they can be disposed frequently during the day, typically at each hand washing session which happens to be the Number One infection control move for hospitals, not face masks but relentless washing.
But, there is a deeper problem and that is turning a whole country into germaphobes and the consequence is that the whole of the society is made more not less vulnerable to the next wave of unknown diseases.
One of the facets of this COVID panic that is only now being discussed is why it didn’t spread like they keep expecting and the answer is starting to become considered that some previous exposure to a Corona virus has already prompted immunity in a large percentage of the population which seems to follow an inverse social distancing pattern with the youngest being the most immune and the least social adults being most vulnerable.
Clearly the regimens of increased requirements for masks is not working or at least having any significant impact, and thus.. even if it is “good” it has downsides that were obvious before KAREN came along to bully everybody into complying.