Kara, Thank you for sharing your journey through masking. Very creative. Excellent description of formal fit testing. I was a Chemical Engineer for 40 years, specialising in air filtration and masking. People have little understanding of masks or filtration. I wore masks of all types industrially. Fit testing flexible nasks is difficult. Your solution is excellent. For full and half face respirators formal fit testing is similar to your procedure as part of training. Informal fit testing done with every donning of the masks is easier. It involves using your palms to cover the air path in the cartridges and inhale. With the air path covered and no leak, the mask pulls in against your face. If it doesn't you have to adjust the mask and try again. Repeat as needed. With practice and experience, it is quick and nearly always passes on the first try. Be careful with the P100's (or N, or R). They are excellent, however the pore size is so small that moisture buildup inside the mask becomes quite a problem, quite rapidly. So does heat and CO2. The CO2 buildup can be minimized by learning to breathe differently - long slow deep inhalations and exhalations. This forces the trapped volume inside the mask out more thoroughly. Air pressure resistance is also a problem for a lot of people. Because of the moisture buildup (liquid), it is vital to wipe out and sterilize the masks after every use, and to periodically wipe them down with fungicide. There are lots of kinds of forced air respirators (PAPRs). The same criteria for fit and filtration efficiency apply. There is much more to know to truly understand filtration. One of the key ideas is called "most penetrating particle size". Air filtration works somewhat differently than liquids. There are four major mechanisms involved. These combine in an interesting way. If you plot efficiency versus size you see a particular particle size range that most passes the filter. At lower sizes, nearly everything is removed. At larger sizes the vast majority are removed. By layering two filter media with vastly different MPPSs, the efficiency is better, and flow resistance is less. By choosing different media with different charge and chemical characteristics removal is vastly improved as well. In total I spent the equivalent of about 5 years 24/7 "on mask. Like many of you I will mask for the rest of my life. I have 5 autoimmune diseases. I will not risk reactivating any of those, or adding a new one. As one more layer of protection... I do recommend you check on the recent science about second generation (non-sedating) antihistamines ability to bind to and block the virus. Obviously, talk with the doc about whether those are reasonable for you. Azelastine tested as having the strongest binding to the virus. This is not for everyone, and has risks.
Oh by the way. Your information is orders of magnitude better than CDC's, even though NIOSH is part of CDC. One piece of trivia. If you search through the CDC site, they do note that any N95 mask with an exhaust valve is more protective than a surgical mask. Surgical masks aren't worth anything other than slowing spittle. CDC's recommendations to the general public in regard to masking for SARS-CoV-2 is utter rubbish and should NOT EVER be relied upon for health protection. It is grossly recklessly inadequate and invalid.
P.s.s Your comment about deer is excellent as well, and a failing in understanding for most "experts" talking about the virus. There are dozens of species now that have there own pandemics of the virus running. White Tailed deer and mink and related species are major in this regard. And with deer in particular, the virus is moving back and forth, though for the moment human to deer is the largest risk. Omicron was not a development in humans. It came from a pandemic in some as-yet unidentified mouse-like rodent species. B.1.1 moved into that species. BA.1 through 5 (Omicron) were end points of their pandemic that then jumped back to humans - radically changing the pandemic. There are others. The KP.2.x and KP.3.x series that the current strains are in come from hybridizations of the Omicron strains. There is grave danger in ignoring the pandemic that other wild type cousins (MERS, NeoCoV, and others) can and are likely to hybridize with SARS-CoV-2 creating a monster that may have very high immediate lethality. However, the accumulative immune damage and life shortening of COVID infections may render that moot, as the consequences of allowing the pandemic to run are accumulating and leading to far more death and disability than is realized.
Kara, Thank you for sharing your journey through masking. Very creative. Excellent description of formal fit testing. I was a Chemical Engineer for 40 years, specialising in air filtration and masking. People have little understanding of masks or filtration. I wore masks of all types industrially. Fit testing flexible nasks is difficult. Your solution is excellent.
For full and half face respirators formal fit testing is similar to your procedure as part of training. Informal fit testing done with every donning of the masks is easier. It involves using your palms to cover the air path in the cartridges and inhale. With the air path covered and no leak, the mask pulls in against your face. If it doesn't you have to adjust the mask and try again. Repeat as needed. With practice and experience, it is quick and nearly always passes on the first try.
Be careful with the P100's (or N, or R). They are excellent, however the pore size is so small that moisture buildup inside the mask becomes quite a problem, quite rapidly. So does heat and CO2. The CO2 buildup can be minimized by learning to breathe differently - long slow deep inhalations and exhalations. This forces the trapped volume inside the mask out more thoroughly. Air pressure resistance is also a problem for a lot of people. Because of the moisture buildup (liquid), it is vital to wipe out and sterilize the masks after every use, and to periodically wipe them down with fungicide.
There are lots of kinds of forced air respirators (PAPRs). The same criteria for fit and filtration efficiency apply.
There is much more to know to truly understand filtration. One of the key ideas is called "most penetrating particle size". Air filtration works somewhat differently than liquids. There are four major mechanisms involved. These combine in an interesting way. If you plot efficiency versus size you see a particular particle size range that most passes the filter. At lower sizes, nearly everything is removed. At larger sizes the vast majority are removed. By layering two filter media with vastly different MPPSs, the efficiency is better, and flow resistance is less.
By choosing different media with different charge and chemical characteristics removal is vastly improved as well.
In total I spent the equivalent of about 5 years 24/7 "on mask. Like many of you I will mask for the rest of my life. I have 5 autoimmune diseases. I will not risk reactivating any of those, or adding a new one.
As one more layer of protection... I do recommend you check on the recent science about second generation (non-sedating) antihistamines ability to bind to and block the virus. Obviously, talk with the doc about whether those are reasonable for you. Azelastine tested as having the strongest binding to the virus. This is not for everyone, and has risks.
Oh by the way. Your information is orders of magnitude better than CDC's, even though NIOSH is part of CDC. One piece of trivia. If you search through the CDC site, they do note that any N95 mask with an exhaust valve is more protective than a surgical mask. Surgical masks aren't worth anything other than slowing spittle. CDC's recommendations to the general public in regard to masking for SARS-CoV-2 is utter rubbish and should NOT EVER be relied upon for health protection. It is grossly recklessly inadequate and invalid.
P.s.s Your comment about deer is excellent as well, and a failing in understanding for most "experts" talking about the virus.
There are dozens of species now that have there own pandemics of the virus running. White Tailed deer and mink and related species are major in this regard. And with deer in particular, the virus is moving back and forth, though for the moment human to deer is the largest risk.
Omicron was not a development in humans. It came from a pandemic in some as-yet unidentified mouse-like rodent species. B.1.1 moved into that species. BA.1 through 5 (Omicron) were end points of their pandemic that then jumped back to humans - radically changing the pandemic. There are others. The KP.2.x and KP.3.x series that the current strains are in come from hybridizations of the Omicron strains.
There is grave danger in ignoring the pandemic that other wild type cousins (MERS, NeoCoV, and others) can and are likely to hybridize with SARS-CoV-2 creating a monster that may have very high immediate lethality.
However, the accumulative immune damage and life shortening of COVID infections may render that moot, as the consequences of allowing the pandemic to run are accumulating and leading to far more death and disability than is realized.