l was thinking of the possibility of using microfiber cloth as a last resort; seems vacuum cleaner bags work decently as well though. Biggest issue is hole sizes; P2/P3 masks need to filter out...
l was thinking of the possibility of using microfiber cloth as a last resort; seems vacuum cleaner bags work decently as well though. Biggest issue is hole sizes; P2/P3 masks need to filter out >80% of particles up to 0.6 μm, not sure what the hole sizes in vacuum cleaner bags/microfiber cloths are. l've got a microscope with scaled lenses, so l could have a look, if l can get enough magnification of course.
Edit: seems 1000x is enough to see 0.18 μm, should be doable.,
Both [homemade] masks significantly reduced the number of microorganisms expelled by volunteers, although the surgical mask was 3 times more effective in blocking transmission than the homemade mask. Our findings suggest that a homemade mask should only be considered as a last resort to prevent droplet transmission from infected individuals, but it would be better than no protection.
A protective mask may reduce the likelihood of infection, but it will not eliminate the risk, particularly when a disease has more than 1 route of transmission. Thus any mask, no matter how efficient at filtration or how good the seal, will have minimal effect if it is not used in conjunction with other preventative measures, such as isolation of infected cases, immunization, good respiratory etiquette, and regular hand hygiene. An improvised face mask should be viewed as the last possible alternative if a supply of commercial face masks is not available, irrespective of the disease against which it may be required for protection. Improvised homemade face masks may be used to help protect those who could potentially, for example, be at occupational risk from close or frequent contact with symptomatic patients. However, these masks would provide the wearers little protection from microorganisms from others persons who are infected with respiratory diseases. As a result, we would not recommend the use of homemade face masks as a method of reducing transmission of infection from aerosols.
This is kind of a big deal - it's not much help to wear any kind of mask which isn't correctly fitted to exclude air exchange around the edges, or might have been touched with unsanitized hands....
This is kind of a big deal - it's not much help to wear any kind of mask which isn't correctly fitted to exclude air exchange around the edges, or might have been touched with unsanitized hands.
Back in the public health days, we had to patiently explain to bearded auto paint shop workers that they wouldn't be protected by half-face chemical masks, because there's no proper seal over hair. Some didn't believe us, until they flunked their blood and urine screens for nasty things like benzene and lead. Their numbers weren't much different from samples taken before the mask program started.
It's much worse with infective agents, where it may only require inhaling or ingesting a single particle to make you ill.
You're better off avoiding the hazard, than wearing an improvised or badly fitted mask which gives you a false sense of security.
l was thinking of the possibility of using microfiber cloth as a last resort; seems vacuum cleaner bags work decently as well though. Biggest issue is hole sizes; P2/P3 masks need to filter out >80% of particles up to 0.6 μm, not sure what the hole sizes in vacuum cleaner bags/microfiber cloths are. l've got a microscope with scaled lenses, so l could have a look, if l can get enough magnification of course.
Edit: seems 1000x is enough to see 0.18 μm, should be doable.,
From the abstract:
Also worth quoting:
This is kind of a big deal - it's not much help to wear any kind of mask which isn't correctly fitted to exclude air exchange around the edges, or might have been touched with unsanitized hands.
Back in the public health days, we had to patiently explain to bearded auto paint shop workers that they wouldn't be protected by half-face chemical masks, because there's no proper seal over hair. Some didn't believe us, until they flunked their blood and urine screens for nasty things like benzene and lead. Their numbers weren't much different from samples taken before the mask program started.
It's much worse with infective agents, where it may only require inhaling or ingesting a single particle to make you ill.
You're better off avoiding the hazard, than wearing an improvised or badly fitted mask which gives you a false sense of security.