Unless you around someone coughing and sneezing, they aren't needed.
"...When people do venture out and interact, they’re likely to spew some saliva. “I don’t want to frighten you, but when people speak and breathe and sing—you don’t have to sneeze or cough—these droplets are coming out,” he says.
"... initial evidence suggests people without symptoms may also transmit the coronavirus without knowing they’re infected. Data from contact-tracing efforts—in which researchers monitor the health of people who recently interacted with someone confirmed to have an infection—suggest nearly half of SARS-CoV-2 transmissions occur before the infected person shows symptoms. And some seem to contract and clear the virus without ever feeling sick. “If I knew who was asymptomatic and presymptomatic [for COVID-19], I’d … triage the face masks to those individuals,” Monto says.
https://www.sciencemag.org/news/2020/03/would-everyone-wearing-face-masks-help-us-slow-pandemic
The droplets in the air if someone has been stupid enough to openly cough or sneeze without making any attempt to cover it, will dissipate in most locations where you aren't in close contact with others, but that's not the main way of transmission, anyway.
It has been reported the virus can remain airborne for hours. So when someone sneezes or coughs it into the air, it may be flying around for hours, onto people's lips, into people's mouths, on or in people's noses, around or on people's eyeballs, etc.
"Is coronavirus airborne like measles?"
"Airborne transmission is “plausible,” according to a study published in the print edition in the peer-reviewed The New England Journal of Medicine this week from scientists at Princeton University, UCLA and the National Institutes of Health. The researchers concluded that the virus could remain airborne for “up to 3 hours post aerosolization.”
https://www.marketwatch.com/story/i...s-and-confirming-facts-of-covid-19-2020-03-12
"Tests indicate coronavirus can survive in the air"
"Federally funded tests conducted by scientists from several major institutions indicated that the novel form of coronavirus behind a worldwide outbreak can survive in the air for several hours.
A study awaiting peer review from scientists at Princeton University, the University of California-Los Angeles and the National Institutes of Health (NIH) posted online Wednesday indicated that the COVID-19 virus could remain viable in the air "up to 3 hours post aerosolization," while remaining alive on plastic and other surfaces for up to three days.
"Our results indicate that aerosol and fomite transmission of HCoV-19 is plausible, as the virus can remain viable in aerosols for multiple hours and on surfaces up to days," reads the study's abstract.
The test results suggest that humans could be infected by the disease simply carried through the air or on a solid surface, even if direct contact with an infected person does not occur.
https://thehill.com/policy/healthca...GtkhWYr_G61muSS0RRLgNDVvtA&mod=article_inline
but that's not the main way of transmission, anyway. It's touching your face - eyes, nose mouth with hands that have touched a taiinted surface.
"The exact mode of transmission of COVID‑19 is unknown at present. However, a person with COVID‑19 is thought to be contagious from the day before their symptoms appear. Studies are ongoing. The information in the following two paragraphs concerns human coronaviruses."
"Coronaviruses usually infect the nose, throat and lungs. In most cases, they are spread by droplets from an infected person, when the person coughs or sneezes, for example. They can also be spread by infected hands. This means that you can contract a coronavirus by touching your mouth, nose or eyes after contact with an infected person or surface."
https://www.quebec.ca/en/health/health-issues/a-z/general-information-about-coronavirus/
As for scarves, balaclavas, etc I wonder how often they'd be cleaned.
I'd suggest after you're out buying groceries & returned, throw it in the laundry.
I'm sure a few layers of Saran wrap would work, too. At least until you suffocate.
Maybe it can be wrapped in a manner allowing sufficient continuous air supply? ;
You may have noticed how many people in China use face masks. It's where the CV-19 started, and the masks didn't stop the spread.
Is there any single safety measure that is 100% effective in stopping the spread? But without those in China - and Singapore, Japan, South Korea, Taiwan, Hong Kong, etc - wearing masks, it's reasonable to conclude the spread of COVID-19 would have been significantly worse. Those countries have been more successful in combating the virus than non mask wearing nations such as the USA & at least several in Europe.
Even health care workers using masks sometimes get infected,
Masks are not 100% safe & are not worn 24 hours a day. People can get infected after they take them off.
so rather than protect, it might give a false sense of securrity,
Not if one is informed. Should health care workers stop wearing them because they "might give a false sense of security"? No.
but hey, if you think it will do something for you, or you're forced into a crowded situation, go for it.
Just like wearing a condom, it's common sense that they make the wearer safer. Everyone should be wearing them.