In reading the comments here I see mention of both N95 and N99. It might not make any difference which is used other than the expected filtration rate (95% versus 99%)
But those filter materials may be something of a bottle neck too (and clearly do compete with providing masks to the medical workers.
We here that X distance between people is the acceptable social distance to be safe from spreading the infection. Current X is 6 feet but I think some have said 10 to 12 feet is still possible for the virus travel.
Anyone know of any studies or models that would allow some form of conversion between X feet and mask rating? The X distances has to be largely about gravity (but these are not parabolic paths but like leaves and feathers). Based on that we should be able to say something like at 6 feet we expect y% of the virus to reach you. At 4 feet y1 and at 10 feet y2%. My expectation would be y2 < y1 < y <<< Origin.
The interpretation I have for the mask is that we say y at any distance = mask rating (95 or 99).
So the mask filtration we could use would be the equivalent of 6 feet (or 8 or 10 or 12 -- whatever the number might be). Or is the potential problem that at X feet the expected exposure is so close to 0 we can call it that so even N99 would not be seen as a good trade off/alternative?
Alternatively, we might find that at X feet the expectation is that we’re looking at 80% of the exposure to be reduces so an N80 mask filter would be equivalent. Then any filtration above that would be acceptable.
It might not make any difference which is used other than the expected filtration rate (95% versus 99%)
It’s harder to breath in a N99 mask then in a N95 mask. It seems that this concern is enough to get hospitals to use N95 masks over N99 masks in health care settings where health care workers are constantly exposed to symptomatic ill patients.
I do think we need to get front line people taken care of first—and that will include both medical and other industries with dangerous environments we need to keep open.
That said, unless we’re claiming the 6 foot (or pick your number) limit is equivalent or better than the preferred mask ratings for the industry don’t we want to consider just what the mask rating equivalent to the social distance rule might be. We may well find that we have a lot of other alternatives that are just as good as 6 feet. That would pretty much free up all the N95 and above materials for those that really need them.
I really have to wonder if we don’t have some really low hanging fruit that for some reason no one wants to pick. The world has already conceded that any mask is better than none but we keep making the comparison of masks to the “gold standard” mask rather than the social distance standard. The latter seems more appropriate to me.
I am starting to look for the source analysis from Lydia Bourouiba’s research to see if that might shed some light.
The interpretation I have for the mask is that we say y at any distance = mask rating (95 or 99).
This simple conversion does not work, since the drop of particle concentration over a certain distance is not fixed and drop size is not fixed. Under very favorable conditions you may get an infectious dose over 60 feet though that is quite unlikely.
But those filter materials may be something of a bottle neck too (and clearly do compete with providing masks to the medical workers.
That is my point. We should start manufacturing masks and filter material en masse NOW so we can provide everyone with a high quality mask in 2 to 3 months. Noone does this at the moment and what is produced is wasted on crappy one way products even most professionals do not use correctly.
In reading the comments here I see mention of both N95 and N99. It might not make any difference which is used other than the expected filtration rate (95% versus 99%)
But those filter materials may be something of a bottle neck too (and clearly do compete with providing masks to the medical workers.
We here that X distance between people is the acceptable social distance to be safe from spreading the infection. Current X is 6 feet but I think some have said 10 to 12 feet is still possible for the virus travel.
Anyone know of any studies or models that would allow some form of conversion between X feet and mask rating? The X distances has to be largely about gravity (but these are not parabolic paths but like leaves and feathers). Based on that we should be able to say something like at 6 feet we expect y% of the virus to reach you. At 4 feet y1 and at 10 feet y2%. My expectation would be y2 < y1 < y <<< Origin.
The interpretation I have for the mask is that we say y at any distance = mask rating (95 or 99).
So the mask filtration we could use would be the equivalent of 6 feet (or 8 or 10 or 12 -- whatever the number might be). Or is the potential problem that at X feet the expected exposure is so close to 0 we can call it that so even N99 would not be seen as a good trade off/alternative?
Alternatively, we might find that at X feet the expectation is that we’re looking at 80% of the exposure to be reduces so an N80 mask filter would be equivalent. Then any filtration above that would be acceptable.
It’s harder to breath in a N99 mask then in a N95 mask. It seems that this concern is enough to get hospitals to use N95 masks over N99 masks in health care settings where health care workers are constantly exposed to symptomatic ill patients.
I think it has more to do with N99 not being available in the filtering facepiece form which are the medical standard with very few exceptions.
I do think we need to get front line people taken care of first—and that will include both medical and other industries with dangerous environments we need to keep open.
That said, unless we’re claiming the 6 foot (or pick your number) limit is equivalent or better than the preferred mask ratings for the industry don’t we want to consider just what the mask rating equivalent to the social distance rule might be. We may well find that we have a lot of other alternatives that are just as good as 6 feet. That would pretty much free up all the N95 and above materials for those that really need them.
I really have to wonder if we don’t have some really low hanging fruit that for some reason no one wants to pick. The world has already conceded that any mask is better than none but we keep making the comparison of masks to the “gold standard” mask rather than the social distance standard. The latter seems more appropriate to me.
I am starting to look for the source analysis from Lydia Bourouiba’s research to see if that might shed some light.
This simple conversion does not work, since the drop of particle concentration over a certain distance is not fixed and drop size is not fixed. Under very favorable conditions you may get an infectious dose over 60 feet though that is quite unlikely.
That is my point. We should start manufacturing masks and filter material en masse NOW so we can provide everyone with a high quality mask in 2 to 3 months. Noone does this at the moment and what is produced is wasted on crappy one way products even most professionals do not use correctly.