5 ms·
The "95" in N95 represents the filtration effectiveness. So _any_ leakage means the mask fails in it purpose of filtration.
by RobertRoberts 5y ago
The "95" in N95 represents the filtration effectiveness.
So _any_ leakage means the mask fails in it purpose of filtration.
- brianmcc 5y agoHence it gives "only" a 70x boost in protection, not a 100% protection cast iron guarantee.
- RobertRoberts 5y agoFor how long? 10 years of exposure with a leaky mask is not 70% any more, more like .05%.
- rootusrootus 5y agoIt's the minimum standard, really. Most reputable N95s seem to hit over 99% in real tests.
- jve 5y agoThis was lately on HN, so you can check yourself: https://www.armbrustusa.com/pages/mask-testing https://www.armbrustusa.com/pages/mask-testing
- GavinMcG 5y agoThat's not true: leakage decreases protection, but there's a scaling relationship rather than a complete elimination of efficacy: https://pubmed.ncbi.nlm.nih.gov/24275016/ https://pubmed.ncbi.nlm.nih.gov/24275016/
- RobertRoberts 5y agoOver a long enough time the efficacy drops to zero.
- tablespoon 5y ago> Over a long enough time the efficacy drops to zero. And in the long run, we're all dead.
- RobertRoberts 5y agoYes, so why are we stressing about this? Just focus on getting healthy and doing the best we can is our long term limit of capability. Masks won't save us.
- FabHK 5y agoSo, no need to use, buy, sell, or produce sun screen. It just increases the time you can stay outside without getting a sunburn from a few minutes to hours. Totally useless. /s
- RobertRoberts 5y agoAll you need is a moment of infection. A single second, one breath of air through a leak in your mask. Sunburn is not even remotely similar.
- GavinMcG 5y agoThis just isn't true. Viral load matters.
- deleted 5y ago[deleted]
- throwhauser 5y agoHow long?
- RobertRoberts 5y agoGood question, doesn't it depend on environment? If you are alone in the woods, the mask will always work forever. If you are in a small room with a dozen infected people coughing...?
- PaulKeeble 5y agoIts 95% at the worst particle size for filtering which is 2.5 microns. Above and below that size they perform substantially better. The minimum size of a covid19 carrying particle is 4.7 microns, resulting in at least 99.7% effectiveness at worst. [1]https://www.ncbi.nlm.nih.gov/labs/pmc/articles/PMC7579175/# https://www.ncbi.nlm.nih.gov/labs/pmc/articles/PMC7579175/# [2]https://pubmed.ncbi.nlm.nih.gov/9487666/ https://pubmed.ncbi.nlm.nih.gov/9487666/
- WithinReason 5y agoAlmost every single time someone links a paper on HN as evidence of their statement, it shows evidence of the opposite of their statement: 2nd paragraph: In a study by Chia et al. (2020), SARS-CoV-2 genes were detected in sampled aerosol particles with diameters >4 μm and 1–4 μm [20]. In a study by Liu et al. (2020), SARS-CoV-2 was detected in submicrometer aerosol particles ranging between <0.25 and 1 μm in diameter via a droplet-digital-PCR-based detection method [21]. In a study by Liu et al. (2020), the maximum SARS-CoV-2 concentrations of 40 and 9 copies per m3 of air were measured in aerosol samples with diameters of 0.25–0.5 μm and 0.5–1.0 μm, respectively [21].
- swader999 5y agoChainlink fence stop sand?
- tablespoon 5y ago>> In a study by Chia et al. (2020), SARS-CoV-2 genes were detected in sampled aerosol particles with diameters >4 μm and 1–4 μm [20]. In a study by Liu et al. (2020), SARS-CoV-2 was detected in submicrometer aerosol particles ranging between <0.25 and 1 μm in diameter via a droplet-digital-PCR-based detection method [21]. In a study by Liu et al. (2020), the maximum SARS-CoV-2 concentrations of 40 and 9 copies per m3 of air were measured in aerosol samples with diameters of 0.25–0.5 μm and 0.5–1.0 μm, respectively [21]. Are those viable virus particles? Because that's what actually matters, not the mere presence of genes. Also, are the smaller droplets as effective at transmission as the larger ones? Scanning the paper, it looks like they get smaller as they desiccate.
- tablespoon 5y ago> The "95" in N95 represents the filtration effectiveness. > So _any_ leakage means the mask fails in it purpose of filtration. What do you mean by that? The "95" is just a statement of its performance characteristics, which literally every well-engineered thing has quantified (and are always less than "perfect"). Now if you want an N95 to meet its specifications, it has to be tightly fitted. However it's a spectrum of effectiveness, and unless the fit is ridiculously bad, the protection factor is still going to be better than a cloth mask, e.g.: poorly well- cloth or fitted fitted No mask surgical mask N95 N95 Perfect |O-------------------------O---------------------------------------------------O--------------O--------O| Don't let the perfect be the enemy of the good.
- timr 5y ago> Don't let the perfect be the enemy of the good. Show one study in a vaccinated population of humans, that demonstrates any real-world effectiveness of masks. The "good" here is never quantified, nor demonstrated. It's always an inference from some mechanism.
- RobertRoberts 5y agoNow add a time component of exposure to the virus. And your graph shows 100% infection rate with every setup that has any kind of leak at some point in time.